Susan H. - dggs.alaska.govdggs.alaska.gov/webpubs/usgs/of/text/of89-0527.pdf · UNITED STATES DEPARTMENT OF INTERIOR GEoL0eK;ALsURVEY Major-element chemistry, radiometric ages, and

UNITED STATES DEPARTMENT OF INTERIOR

GEoL0eK;ALsURVEY

Major-element chemistry, radiometric ages, and locations

of samples from the Petersburg and parts of

the Part Alexander and Sumdum quadrangles,

southeastern Alaska

BY

Susan L. ~ o u g l a s s l . John H. webster2 , Peter D. ~ u r r e l l ~ ,

Marvin L. ~anphere l , and David A. ~ r e w l

Open-File Report 89-527

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial

standards or with the North American Stratigraphic Code. Any use of trade, firm, or product names is for descriptive

purposes only and does not imply endorsement by the U.S. Government.

1 Menlo Park, California

Deceased

3 Present address: 1465A Big Basin Way, Saratoga, CA 95070

Contents

Page

I n t r o d u c t i o n .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , , . , . . . . . . . . , . . . . . . . . , . . . , . . . . l Refe rences c i t e d .......................................~....,.............66

Tables

1 . XRF chemical a n a l y s e s , CIPW norms, and s e l e c t e d modes of r o c k samples from t h e P e t e r s b u r g and p a r t s of t h e P o r t Alexander and Sumdum q u a d r a n g l e s , s o u t h e a s t e r n Alaska... . . . . ................ 3

2. P e t r o g r a p h i o d e s c r i p t i o n s of sample l o c a l i t i e s . . . . . . .................. 32

3. Potass ium-argon d e t e r m i n a t i o n s i n t h e P e t e r s b u r g and p a r t s of t h e P o r t Alexander and Sumdum 1 :250,000 q u a d r a n g l e s , s o u t h e a s t e r n Alaska ............................................................6 3

Plate

1. Map showing l o c a t i o n s of major-element geochemical and r a d i o m e t r i c age samples i n the P e t e r s b u r g and p a r t s of t h e a d j a c e n t P o r t Alexander and Sumdum q u a d r a n g l e s , s o u t h e a s t e r n Alaska.

INTRODUCTION

T h i s r e p o r t is a c o m p i l a t i o n of major-element geochemical , p e t r o g r a p h i c , and geochrono log ic d a t a o n r o c k samples from t h e P e t e r s b u r g and p a r t s of t h e a d j a c e n t P o r t Alexander and Sumdum q u a d r a n g l e s , Alaska. C o l l e c t i o n of t h e 341 samples was pa r t of t h e r e c o n n a i s s a n c e mapping e f f o r t which produced t h e p r e v i o u s l y p u b l i s h e d U. S.Geologica1 Survey g e o l o g i c map of t h e a r e a (Brew and o t h e r s , 1984). Although t h e r o c k u n i t t e r m s used o n t h a t map a g r e e w i t h t h o s e i n t h i s r e p o r t , one u n i t , i n c o r r e c t l y l a b e l e d "TmdW o n t h e 1984 g e o l o g i c map, is h e r e r e l a b e l e d "QTdW.

The f o l l o w i n g i t e m s are i n c l u d e d i n t h i s r e p o r t : ( 1 ) a t a b l e o f major- e lement chemical a n a l y s e s , CIPW (Cross and o t h e r s , 1902) normat ive m i n e r a l s , and s e l e c t e d modes (Tab le 1 ) ; ( 2 ) b r i e f p e t r o g r a p h i c d e s c r i p t i o n s of each ana lyzed sample ( T a b l e 2) ; ( 3 ) potassium-argon d e t e r m i n a t i o n s f o r selected samples (Tab le 3 ) ; and ( 4 ) a 1 :250,000-scale s a m p l e - l o c a t i o n map ( p l a t e 1 ) .

Samples are l i s ted i n T a b l e 1 by map u n i t and by d e c r e a s i n g weight p e r c e n t s i l i c a d i o x i d e . Corresponding f i e l d numbers and map numbers ( s e e p l a t e 1 of t h i s r e p o r t ) are a l s o given. The major-element chemical a n a l y s e s were performed a t t h e USGS Denver and Menlo Park f a c i l i t i e s u s i n g t h e X-ray f l u o r e s c e n c e spec tomet ry (XRF) t e c h n i q u e s as d e s c r i b e d by Taggar t and o t h e r s (1987) . Rapid r o c k a n a l y s e s a r e by t h e method of S h a p i r o (1975) . Lab v a l u e s a r e l i s t e d a s r e p o r t e d ; normal ized o x i d e and CIPW normat ive m i n e r a l p e r c e n t a g e s have been rounded t o r e t a i n t h e c o r r e c t number of s i g n i f i c a n t f i g u r e s . Thus t h e sums of t h e normal ized o x i d e and normat ive v a l u e s may a c t u a l l y be p l u s o r minus 0.01 p e r c e n t from 100. Those rock samples ana lyzed by r a p i d r o c k , o r a n o n - s p e c i f i e d method ( v a l u e s t a k e n from Buddington and F a i r c h i l d (1 932)), are i n d i c a t e d i n T a b l e 2.

T a b l e 2 p r o v i d e s a d d i t i o n a l i n f o r m a t i o n o n t h e pe t rography ( i n c l u d i n g a l t e r a t i o n m i n e r a l s ) , l a t i t u d e / l o n g i t u d e , and 1 :63,360-scale quadrang le l o c a t i o n s f o r e a c h of t h e samples l i s t e d i n T a b l e 1. I n t r u s i v e rock names are based on modal d a t a and a r e c l a s s i f i e d a c c o r d i n g t o S t r e c k e i s e n (1973) ( a l t h o u g h i n some c a s e s , chemical a n a l y s e s show abnormal ly low S i02) .

The potassium-argon d e t e r m i n a t i o n s i n T a b l e 3 a r e p r e v i o u s l y unpubl ished. Here , t h e y are l i s t ed by i n c r e a s i n g g e o l o g i c age and a l s o by g e o l o g i c map u n i t of B r e w and o t h e r s (1984) . A l l a g e s have been c a l c u l a t e d u s i n g t h e abundance and decay c o n s t a n t s o f S t e i g e r and J a g e r (1977) .

T a b l e 1--XRF chemical and lyses , CIPW norus. and s e l e c t e d modes o f r o c k samples from the P e t e r s b u r g and p a r t s of

P o r t A lexander and Sumdurn quadrangles , southeastern Alaska

(Major e lements by q u a n t i t a t i v e x - r a y spectroscopy; a n a l y s t s : J. Baker . A. B a r t e l . L. Espos, T. Holmes, G. Kawakita. R. Lerner . J.

T a g p a r t . J.S. Y a h l t e r g . FeO by chemical method; a n a l y s t s : L. A r t i s , E . Brandt . Z.A. Harnlin, P . K lock , 0. K o b i l i s . G. &son, V .

M c 0 a n i e l . F. N e w a n . J. Pastore. J . R i v e l l o . J. Ryder, D. Shepard. N. S k i n n e r )

U n i t Qb Qtr

Hap No. 1 ** 2 3" 4 ** 5 ** 6 7 ** 8 9 l o f Z 11 12 F i e l d No. BUDD-006 78SH054A 71ABg179 71ABgl78 80-3 79AF031A 71ABg189 79AF029A 82RK8520 BUOD-002 82SK167A 80080568

XRF chemical a n a l y s e s ( w e i g h t p e r c e n t )

Si02 52.05 50,45 49.7 48.8 48.66 48.24 47.9 47.89 47.7 46.60 76.8 76.6

A' 2O3 15.03 14.38 15.4 14.9 13.40 16.45 14.6 15.09 16.2 14.55 11.2 12.1

Fe203 2.78 4.29 2.8 1.5 1,29 2.34 2.4 4.34 4.2 2.49 0.88 0.20

FeO 5.54 8.50 9.5 10.6 11.58 7.07 9.9 7.77 7.98 9.70 1.02 0.92

CaO 9.27 7.87 8.9 8.7 8.92 9.24 9.5 8.85 9.00 8.59 <0.02 0.28

K2° 1.01 1.39 0.51 0.55 0.80 1.01 0.38 0.52 0.85 1.28 4.89 4.24 f iOz 1.42 2.58 0.77 0.89 2.77 1.58 0.70 1.67 2.74 2.73 0.13 0.10

P2°5 0.28 0.74 0.26 0.27 0.35 0.44 0.20 0.23 0.50 0.54 <0.05 <0.05 HnO 0.07 0.19 0.14 0.17 0.12 0.16 0.17 0.16 0.21 0.19 <0.02 <0.02

LO I 5.70 0.40 0.59 0.27 1 1 1.59 1.26 0.16 0.95 0 4 4

T o t a l 100.42 97.25 100.38 98.97 100.22 97.25 99.24 99.33 98.82 99.95 98.69 98-50

Oxides n o r m a l i z e d t o 100%

CaO 9.79 8.09 8.9 8.8 8.92 9.50 9.7 8.91 9.22 8.61 0.02 0.29

P2Q5 0.30 0.76 0.26 0.27 0.35 0.45 0.20 0.23 0.51 0.54 0.05 0.05 HnO 0,07 0.16 0.14 0.17 0.12 0.16 0.17 0.16 0.22 0.19 0.02 0.02

CIPU n o r m a t i v e m i n e r a l s

Q 9.72 4.73 0.1 43.2 39.8 C 1.6 1.5

Or 6.30 8.45 3.0 3.3 4.73 6.14 2.3 3.09 5.1 7.58 29.6 25.5

Ab 20.81 30.10 24.5 24.9 28.27 29.93 26.0 27.60 20.7 22.27 22.8 29.8

LO1 - Loss on i g n i t i o n . lio LO1 s p e c i f i e d i n l a b r e p o r t +* = Non-XRF a n a l y s i s - sec T a b l e 2

t a b l e I--XRF chemical analyses. CIPU norms. and se lected modes o f rock sanples from the Petersburg and par ts o f t he

Por t Alexander and Sumdum quadracgles. southeastern Alaska--Continued

----- ~ n i t PT r

Hap 40. 13 14 15 16** 17 18 19 20 21** 22 2 3 24 F i e l d Ho. 80SK537A 8ZOB180A 79SK178A 86-44 8206199A 82SKl80A 83SK414C 83311601 BUDD-003 82SK178A 82SK179A 7433036d

XRF chemical analyses (weight percent)

S i02 76.3 76.2 76.19 76.18 76.1 75.8 75.7 75.6 75.47 75.3 75.0 73.91

A1203 12.3 11.6 11.48 12.95 12.6 12.0 12.3 12.8 9.39 12.1 11.9 13.25

Fe203 0.47 1.71 0.46 0.01 0.83 1.09 1.53 1.00 1.21 1.00 1.33 1.03

Mgo 0.14 0.10 0.19 Trace 0.11 c0.10 0.18 0.13 0.10 <0.10 <O.lO 0.3

'2O5 c0.05 <0.05 0.02 Trace <0.05 <0.05 x0.05 <O.05 0.05 cO.05 c0.05 0.04

MnO cO.02 <0.02 0.038 Trace c0.02 x0.02 <0.02 c0.02 0.00 <0.02 <0.02 0,06

-- -- - - - -- -

Total 99.40 99.21 97.99 99.30 99.62 98.91 99.67 99.55 98.47 98.48 98.68 97.61

Oxides normal ired to 100%

Si02 77.5 77.1 77.75 76.68 77.0 77.4 77.0 76.5 77.62 77.1 76.8 75.72 *' 2O3 12.5 11.7 11.71 13.04 12.7 12.3 12.5 12.9 9.66 12.4 12.2 13.57

Fe203 0.48 1.65 0.47 0.01 0.84 1.11 1.56 1.01 1.24 1.03 1.36 1.06 FeO 0.70 0.54 1.33 2.64 0.12 0.63 0.12 0.20 3.40 0.33 1.20 1.21

CaO 0.52 0.02 0.20 0.05 0.49 0.02 0.38 0.52 0.10 0.02 0.02 0.31

T i02 0.08 0.13 0.14 0.15 0.19 0.13 0.23 0.19 0.67 0.13 0.14 0.21

'2O5 0.05 0.05 0.02 0 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.04 HnO 0.02 0.02 0.04 0.01 0.02 0.02 0.02 0.02 0.00 0.02 0.02 0.06

CIPV normative minera ls

Q 38.3 35.5 40.65 37.79 37.5 39.3 39.5 36.2 43.07 39.7 38.4 35.78

C 1.1 0.0 1.33 2.45 1.1 1.5 1.6 1.1 0.42 1.9 1.5 2.24

Or 28.0 27.2 34.86 27.30 30.9 29.2 27.8 29.8 27.11 28.7 27.4 15.56

Ab 28.2 34.6 18.91 28.36 26.9 27.8 27.0 28.8 21.67 27.2 29.4 41.26

An 2.2 0 . a 0.18 2.1 1.5 2.2 0.17 1.26

- -

* - No LO1 spec i f i ed i n l a b r e p o r t .* = Non-XRF ana lys i s - see f a b l e 2

Table 1--XRF chemical analyses. ClPW norms. and se lected modps of rock samples from the Petersburg and pa r t s o f th:

Por t Alexander and Surdur quadrangles. southeastern A1 sska--Continued

Map No. 25 26 2 7 28 2 9 30 31 32 33 34 35+* 36 F i e l d No. 83SK467A 83SK422A 79DB133R 82KR114A 835K4228 83DB142A 83DB151A 83SK418A 80SK536A 83SK436A B113G-008 83SK415A

X R f chemical analyses (weight percent)

Si02

2O3

Fe203 FeO

nao CrO

Na20

K2O Ti02

"205 nno

LO 1

To ta l 99.71 99.32 97.46 98.37 99.43 99.29 99.87 99.12 99.41 99.35 100.36 99.48

Oxides normal i zed t o 100%

CIPW normative minera ls

0 34.0 42.0 36.86 37.4 35.1 26.9 36.0 35.9 26.5 27.1 17.87 21.4 C 1.0 2.6 2.08 3.5 1.2 1.4 0.4 0.0

Or 36.7 41.0 19.22 26.0 14.7 29.00 18.1 24.4 24.9 37.5 17.81 27.0

Ab 24.1 9.3 27.78 25.2 43.4 37.9 38.7 23.6 34.9 17.5 49.17 33.8

An 1.9 2.9 8.73 3.3 3.6 7.6 6.9 4.27 10.6 Ne

Ac 1.4 7.3

R = No LO1 s p e c i f i e d i n l a b r e p o r t s+ = Non-XRF ana lys i s - see Table 2

Table 1--XRF chemical analyses, CIP'k' norms. 2 :d selected modes of rock samples from the Petersdurg and par ts o f the

Port Alexander and Surrdun quadrangles, southeastern Alaska--Continued

Map No. 37 38 39 40 4 1 42** 43 4 4 45 46 47 46 F i e l d l o . 8ZPE067A 8300139A 82SK175A 82RK64;A 83D87216 7a9GOS9C 8DDB056A 745k001i aZKROlSA 82KXLLGA 6 l S k J i 5 A 74DY~ll iA


S i 0, 58.6 55.4 49.6 49.1 48.8 45.6 44.2 55.49 68.0 66.7 63.i 52.44

CaO 4.85 6.70 7,W 7.70 9.49 10.01 8.17 6.99 1.87 2.41 1.68 7.57

HnO 0.13 0.13 0.23 0.24 0.15 0.3 0.17 0.11 0.11 0.11 0.17 0.18

LO1 1.32 4.38 0.10 1.22 2.58 5.80 6.70 1.84 2.26 1.63 n

Total 98.84 99.35 98.44 98.90 99.26 99.09 97.26 55.97 98.65 98.83 94.16 98.31

Oxjdes nomal lzed t o lOUL

Sf02 60.1 58.4 50.8 50.3 50.5 48.9 48.8 57.82 70.L 69.2 64.9 53.93

2'3 17.4 16.0 14.1 14.3 19.4 19.1 18.2 18.1 13.6 13.5 14.6 15.91

Fe203 2.30 2.8 4.2 4.8 2.7 4.0 1.7 2 . U 4.5 3.37 4.40 0.67

FeO 4.23 5.1 9.60 10.11 6.6 5.4 9.11 3.20 4.55 4.22 3.8 7.06

HgO 2.30 3.59 4.04 3.64 5.30 4.9 6.99 2.2 0.25 0.34 0.31 3.7 CaO 4.97 7.06 8.08 7.88 9.82 10.8 9.02 7.28 1.93 2.50 1.72 7.71 Ha20 4.82 3.65 3.17 3.46 3.66 3.9 2.88 4.44 3.89 3.83 4.26 4.60

K2O 2.C2 1.90 1.73 1.13 0.15 0.63 1.10 0.87 4.26 3.63 4.95 1.29

T i Q 1.24 1-15 3.44 3.31 1,39 1.7 1.77 1.33 0.40 0.52 9.66 1.84

"205 0.47 0.28 0.64 0.56 0.29 0.4 0.25 0.21 0.05 0.08 0.12 0.43

Hn3 0.13 0.14 0.24 0.25 0.15 0.3 0.19 0.11 0.11 0.11 0.17 0.18

CIPW nonnative minerals

He

+ * No LO1 speci f ied i n l a b report .. - kon-XRF analysis - see Tdble 2

Table 1--XU: chemical analyses, CIPY norms. and selected modes o f rock simples fm the Pctersburg and parts o f tne Port Alexander and Sumdus quadrangles. southeastern ~l aska--Conti nued

Unit QTa QTb - -

Map No. 49 50 51 52 53 54 55 56 57 58 54 60 Field No. 79060371 79SH002A 79SHWA 850B209A 83SK469A 82KR009 85DB170A MDB277A BODBl84A WDBlYbA 82KH117A 780bZJL~

XRF chemlcsl analyses (weight percent)

Total 93.83 93.61 98.35 99.11 99.56 99.21 99.31 98.87 100.28 99.56 98.50 97.11

Oxides nonnal i r e d t o 10W

Si02 55.61 54.61 49.85 49.4 49.6 73.4 1 57.6 56.9 55.2 63.4 53.ri

A] z03 16.65 15.52 16.00 15.8 16.2 14.2 15.4 17.9 18.4 16.1 17.3 17.65

Fe203 1.93 3.60 4.36 5.1 6.6 0 . a 4.2 2.96 2.81 2.3 4.5 3.74

FeO 7.49 6.49 8.22 9.2 7.3 1.70 5.6 4.91 4.40 7.72 5.84 5 . 7 ~

4 0 3.3 3.7 4.5 4.16 3.96 0.13 2.85 2.88 3.22 3.49 3.W 5.ui CaO 7-41 8.45 8.86 8.05 7.79 0.70 6.38 5.44 7.56 7.40 6.64 6.17


No LO1 speci f ied i n l ab report

fab le 1--XRF chemical analyses, ClPU norms, and selected modes o f rock samples f rom the Petersburg and p a r t s o f the

Por t Alexander and Sumdum quadrangles, southeastern Alaska--Continued

-- --- Unit PT b QT c

Map No, 61 62 63 64 65 66 67 68 69 70 71f* 72 F i e l d No. 83SK413A 79DG041A 82RK719A 79DB029A 830B196A 82PB132A 82Pa1390 82SH013A 82SK168A 83DB200A BUOD-007 79DG040A


Si02

A' 2O3

Fe203 FeO

n90 CaO

NaZO

K20 T i02

'z05 MnO

LO1

Tota l 98.87 98.09 99.18 98.33 98.99 99.00 99.45 99.07 99.03 99.05 100.01 95.81

Oxides normalized to 100%

s t02

*' 2'3 Fe203 FeO

nil0 CaO

Wa20

K20 Ti02

P2"5 HnO

-. - -- - - - -.

C l P U nonnative minera ls

He 5.93

- No LO1 s p e c i f i e d i n l a b report - Non-XRF analys is - see Table 2

Table 1--YRF chemical analyses, ClPU norms, and selected modes o f rock samples from the Pettrsburg and parts o f the Port Alexander and Sumdum quadrangles, southeastern Alaska--Continued

- Uni t QTc QTd

Hap No. 73 74 75 76 77 78 79 80 E l * * 82 83** 83 F i e l d No. 8006175A 80RS084A 79DB1216 82SH009C 780V040A 793G035A 82SH009A 80SK472A BUDD-005 82SH061A BUDD-004 82PB064A


S io2

A' 2O3

Fez03 FeO

- - -

Total 99.71 99.02 98.66 98.92 96.25 93.45 98.51 98.96 100.35 98.36 99.62 99.25

Oxides normalized t o 100%

Sio2

A' 2'3

Fez03 FeO

HgO CaO

Na20

K20 Ti02

'2O5 HnO

---

CIPU normative minerals

- --

* No LO1 spec i f i ed i n l a b repor t *+ Non-XRF analysis - see Table 2

Table 1--XRF chemical analyses. CIPU norms, and selected modes o f rock samples from the Petersburg and parts o f the Port I lexander and Sumdum quadrangles, southeastern Alaska--Continued

Unl t QT 6 Tmae Trnge I

Map No. 85 86 87 88 89 90 91 92 93 94 95 96 F fe ld No. 82PB065A 825H0098 79DB139A 80DB057A 79SK088A 81RK266A 79DG114A 81RK268A 8ltM063C 79SK15lA 81RK271A 81TM062B


Si02 49.1 44.9 77.01 76.5 73.60 66.8 61.55 76.9 76.5 76.34 76.2 76.0

A1203 16.8 18.1 12.30 11.4 13.17 15.5 14.84 12.5 12.8 12.89 12.8 12.8

Fezof 2.33 2.3 0.92 1.06 1.03 1.66 1.34 0.37 0.89 0.48 0.88 0.51

Fa0 6.82 7.39 -0.73 0.89 1.36 2.46 6.75 0.57 0.19 0.62 0.32 0.51

ngo 4.38 7.84 0.17 <0.10 0.40 0.33 0.67 0.11 <0.10 0.13 <0.10 <0.10

CaO 10.0 10.2 0 0.03 0.71 1.11 2.92 0.37 0.12 0.28 0.20 0.39

Na20 2.60 2.26 3.90 4.04 3.98 4.97 4.40 3.47 3.91 3.53 3.86 3.91

-

Total 99.30 99.06 99.99 98.81 98.94 98.85 98-34 99.39 99-30 99.44 99.63 99-42


Si02 51.6 47.3 77.02 77.5 74-39 67.7 62.59 77.6 77.0 76.77 76.7 76.6

2O 3 11.7 19.1 12.30 11.7 13.31 15.7 15.09 12.6 12.9 12.96 12.9 12.9

Fe203 2.45 2.4 0.92 1.07 1.04 1.68 1.36 0.37 0.90 0.48 0.89 0.51

FeO 7.17 7.79 0.73 0.90 1.37 2.49 6.86 0.58 0.19 0.62 0.32 0.51

HgO 4.61 8.27 0.17 0.10 0.40 0.33 0.68 0.11 0.10 0.13 0.10 0.10

CaO 10.5 10.8 0.34 0.03 0.72 0.12 2.97 0.37 0.12 0.27 0.20 0.39

Na20 2.73 2.38 3.90 4.09 4.02 5.03 4.47 3.50 3.94 3.55 3.89 3.94

K2° 0.80 0.25 4.44 4.48 4.39 5.21 4.80 4.67 4.69 5.04 4.83 4.84

Ti02 1.79 1.35 0.12 0.06 0.23 0.55 0.72 0.06 0.06 0.11 0.06 0.07

'2O5 0.46 0.21 0.03 0.05 0.07 0.07 0.14 0.05 0.05 0.03 0.05 0.05 MnO 0.17 0.16 0.03 0.02 0.05 0.15 0.31 0.02 0.02 0.03 0.02 0.02

- -

CIPU nonnative minerals

He 0.55 0.24

Modal calculat ions (percent volume)

K-feldspar

Plagioclase

Quartz '

M a f i c minerals

To ta l -- -. ~. - -.

No 101 specif ied i n lab report

Table 1--XRF chemical analyses. ClPU norms. and selected aodes of rock samples from the Petersburg and parts of the Port Alexander and Surndum quadrangles, southeastern Alaska--Cont$nued

Un i t Tmge

llrp No. 97 98 99 100 101 102 103 104 105 106 107 108 F i e l d No. 81R1064A 81tW065A 81SH043C 81TH0618 78RS121B 820B097A 82DB2634 82Sd107A 82RK703A 12SK149A 82DB095A 79SH059A


S102 75.2 75.2 75.0 74.3 74.20 72.7 72.6 72.2 72.2 71.9 70.6 70.24

*'2O3 13.1 13.3 13.4 13.5 13.51 13.8 13.9 14.1 14.1 13.9 14.2 14.33 Fe203 0.71 0.92 0.82 0.81 0.89 0.78 0.26 0.79 0.96 0.91 0.44 1.03

FeO 0.43 0.36 0.52 0.51 0.95 1.03 1.29 0.91 0.96 0.97 1.90 1.94

<0.10 <0.10 <0.10 0.16 0.23 0.22 0.33 0.18 0.19 0.14 0.60 0.38

CaO 0.30 0.19 0.27 0.40 0.60 0.72 1.05 0.80 0.69 0.72 1.42 1.56

Ha20 3.92 3.78 4.08 3.76 3.92 4.09 3.53 3.93 4.14 4-11 3.82 4.09

K2° 4.78 4.76 4.74 5.01 5.05 5.02 4.92 5.04 5.09 4.83 4.82 4.25

TiOZ 0.06 0.07 0.08 0.11 0.20 0.17 0.23 0.17 0.19 0.14 0.28 0.34

P2°5 <0.05 <0.05 <0.05 <0.05 0.03 e0.05 <0.05 <0.05 <0.05 0.06 <0.05 0.06

MnO <0.02 C0.02 CO.02 <0.02 0.04 0.02 <0.02 <0.02 0.03 0.03 0.04 0.05

LO1 0.30 0.70 0.30 0.26 t 0.39 0.31 0.15 0.44 0.89 0.75 n

Total 98.97 99.45 99.38 98.89 99.62 99.07 98.49 98.34 99.04 98.59 98.93 98.27

Oxides normallzed t o 100%

SiOZ

*'2O3

Fe203 FeO

"go CaO

Na20

K20 Ti02

P2°5 MnO

ClPW normative minerals

q 33.8 35.0 32.8 32.7 30.30 27.9 30.4 28.4 27.1 28.2 25.4 25.87 C 1.1 1.7 1.2 1.3 0.58 0.5 1.0 0.9 0.7 0.7 0.3 0.31

Or 28.6 28.5 28.3 30.0 29.96 30.1 29.6 30.3 30.5 29.2 29.0 25.56 Ab 33.6 32.4 34.8 32.3 33.29 35.1 30.4 33.9 35.5 25.6 32.9 35.22

An 1.2 0.6 1.0 1.7 2.79 3.3 4 .9 3.7 3.1 3.3 6.8 7.48

Il e

W 0 En 0.3 0.3 0.3 0.4 0.57 0.6 0.8 0.5 0.5 0.4 1.5 0.96 Fs 0.1 0.2 0.1 0.76 1.0 1.8 0.8 0.7 0.9 2.8 2.28

Fo

Fa

M t 1.04 1.03 1.20 1.19 1.30 1.15 0.38 1.17 1.41 1.35 0.65 1.52 11 0.11 0.13 0.15 0.21 0.38 0.33 0.45 0.33 0.37 0.27 0.54 0.66

AP 0.12 0.12 0.12 0.12 0.07 0.12 0.12 0.12 0.12 0.12 0,14 0.14 He 0.22

Modal calculations (percent volume)

K-feldspar 64.0 59.5 56.4 59.4 59.0 44.4 52.4 Plrgioclrse 12.0 8.7 15.1 12.2 10.7 26.4 21.9 Quartz 20.0 28.7 26.1 24.3 28.7 23.0 20.7 Mafic 3.0 3.2 2.4 4.1 1.6 6.2 5.0

minerals

Total 99.0 100.1 100 100 100 100 100

No LO1 spec i f i t ' ;, l;b report 11

Table 1--XRF chemicsl analyses. ClPW norms, and selected modes o f rock samples from the Petersburg and parts o f the Port Alexander and Sumdum quadrangles, southeastern Alaska--Continued

Un i t Tmne .- -

Map No. 109 110 111 112 113 114 115 116 117 118 119 120 F i e l d No. 7AAll4 8208260A 82TM0598 79AF020A 82KRO90A 79SK083A 81SK169C 81TM061A 82RK8368 82KR089A 8208254A 79RS131A


Si02 74.6 68.8 63.56 63.1 61.47 60.5 59.2 58.5 57.4 57.0 56.70

At203 13.2 15.3 16.33 16.1 16.75 1 6 7 17.5 17.3 16.3 17.6 15.42

F e ~ 0 3 0.18 1.53 1.45 0.99 1.51 0.56 1.51 1.19 0.71 0.52 0.64 FeO * 1.03 .1.95 3.01 3.95 3.69 4.28 4.20 5.29 6.42 6.16 7.65

Mso r 0.14 0.37 1.71 1.70 2.92 2.58 2.63 1.96 3.16 3.23 3.25 0

CaO I 0.57 1.38 3.31 3.62 4.91 5.17 5.76 4.73 6.35 6.41 6.16 + Na2O I v 3.62 4.51 4.W 3.77 4.42 4.02 4.05 4.51 3.67 3.25 3.75

K20 01

P 4.90 4.88 3.64 3.67 2.52 2.31 2.55 1.93 1.90 2.11 1.93

Ti02 0.12 0.40 0.81 0.91 0.87 0.91 0.84 1.09 1.65 0.86 1.81

'205 <0.05 0.07 0.23 0.29 0.26 0.31 0.33 0.44 0.44 0.28 0.43 HnO <0.02 0.08 0.096 0.09 0.11 0.08 0.12 0.14 0.12 0.15 0.14

LO1 0.34 0.17 t 0.43 1 1.67 0.68 1.25 0.28 0.89 e

Total 98.77 99.44 98.69 98.62 99.43 99.09 99.37 98.33 98.40 98.46 97.88

Oxldes normalized t o 100%

Si02 75.8 69.3 64.40 64.3 61.82 62.1 60.0 60.3 58.5 58.4 57.93

*I 2O3 13.4 15.4 16.55 16.4 16.85 17.1 17.7 17.8 16.6 18.0 15.75

re203 0.18 1.54 1.47 1.01 1.52 0.57 1.53 1.23 0.72 0.53 0.65

FeO 1.05 1.96 3.05 4.02 3.71 4.39 4.26 5.45 6.54 6.31 7.82

M go 0.14 0.37 1.73 1.73 2.94 2.65 2.67 2.02 3.22 3.31 3.32 CPO 0.58 1.39 3.35 3.69 4.94 5.31 5.84 4.87 6.47 6.57 6.29

Ha20 3.68 4.54 4.60 3.84 4.44 4.13 4.10 4.65 3.74 3.33 3.83

K2° 4.98 4.92 3.69 3.74 2.53 2.37 2.58 1.99 1.94 2.16 1.97 Ti02 0.12 0.40 0.62 0.93 0.88 0.93 0.85 1.12 1.68 0.88 1.85

P2°5 0.05 0.07 0.23 0.29 0.26 0.32 0.33 0.45 0.45 0.28 0.44 MnO 0.02 0.08 0.10 0.09 0.11 0.08 0.12 0.14 0.12 0.15 0.14

CIPW normative minerals

Hodal calculations (percent volume)

K-feldspar 58.9 38.9 20.5 10.8 5.9

Plagioclase 17.5 41.4 40.4 58.4 73.5

Quartz 18.1 6.6 13.9 8.4 1.6

M a f i c minerals

Total 100 99.8 100 100 100

No LO1 specified i n l a b report

Table l--SF chemical analyses, CIPW norms. and selected modes of rock Samples from the Petersburg and par ts o f the Por t Alexander and Sumdum quadrangles, southeastern Alaska--Continued

U n i t Tame Tmn z Tmqk ------- - - - - Hap No. 121 1.22 123 124 125 126** 127 128 129 130 r 31 132*= F i e l d No. 82SK157A 79RS068A 820B262C 82SK154A 82KRO86A 78BG016A 82SK004A 79DB121A 79DG098A 82RK700A 79SK130A BUDD-009

XRF chemical analyses (ueight percent)

Si02

2O3

Fc203 FeO

"90 CaO Na20

K20 f i02

P2°5 HnO

LO1

72.62

10.17

4.50

1.88

0.10

0.10

4.53

4.78

0.35

t r a c e

t r a c e

0.45

Tota l 98.64 99.36 98.54 98.67 98.99 98.07 99.30 99.67 98.90 98.92 97.30 99.58


-- -

CIP2 normative minera ls

nodal ca lcu la t ions (percent volume)

Plagioc lase 60.9 16.2 11.8 3.9 6.7

Quartz 2.1 33.9 34.9 32.6 21.7 20.1 Naf ic 37.0 0.9 3.4 3.0 3.5 4.2

minerals

To ta l 1 00 100 100 100 100 100

* No LO1 s p e c i f i e d i n l a b repor t .* Nan-XRF ana lys i s - see Tab le 2

Table 1--XRF chemical analyses. CIPU norms, and selected modes o f rock samples from the Petersburg and parts of the Port Alexander and Sumdum quadrangles, southeastern Alaskr--Continued

U n i t Tmqk -- -- -. -

Hap No. 133 134 135 136 137 138 139 140 141 142 143 144 F l e l d No. 82KR014A 83KR017A 82KR015A 81KRO16A 79RS155A 82SH052A 780B223A 800B069A 83SK476A 82SH060A 8500202A 790G039A -. - - -

XRF cheml cal analyses (weight percent)

A1203 10.0 9.54 9.92 10.0 14.47 14.4 15.26 16.1 15.1 15.1 14.9 16,75

Fe203 4.88 5.98 6.00 6.37 1-15 1.88 1.67 1.64 2.7 0.81 3.6 2.55 FeO 0.34 0.51 0.62 0.61 1.53 1.62 1 . 9 2.69 2.5 3.78 5.6 7.24

CaO 0.07 0.16 0.12 0.12 1.13 0.11 2.17 2.77 2.09 2.65 5.47 10.98

'(20 4.43 4.03 4.37 4.19 4.80 3.66 3.10 2.74 3.72 2.91 2.41 0.87

T i02 0.23 0.28 0.27 0.31 0.40 0.42 0.63 0.74 0.63 0.70 1.62 0.75

P ~ 0 5 €0.05 ~ 0 . 0 5 €0.05 <0.05 0.07 0.07 0.15 0.20 0.15 0.21 0.40 0.24 MnO 0.04 0.08 0.07 0.11 0.06 0.08 0.08 0.09 0.1 0.14 0.19 0.17

LOI 0.51 0.28 0.42 0.64 0.25 0.56 0.86 3.39 1.39

Tota l 99.35 99.15 99.00 99.06 98.68 98.82 97.43 99.70 98.94 98.93 99.44 98.06


SiOz 74.9 73.9 73.1 72.6 70.84 70.9 68.37 66.6 66.8 66.8 57.8 50.88

A1 2O3 10.1 9.69 10.11 10.2 14.66 14.6 15.66 16.2 15.4 15.8 15.2 17.08

4.94 1.81 1.80 1.85 1.47 1.91 1.71 1.65 2.7 0.85 3.6 2.29

FeO 0.34 4.36 4.51 4.81 1.55 1.64 1.99 2.71 2.5 3.96 5.7 7.66

Milo 0.10 0.10 0.10 0.10 0.55 0.42 1.02 1.19 0.69 1.10 2.76 5.7

CaO 0.07 0.16 0.12 0.12 1.14 1.13 2.23 2.79 2.13 2.77 5.58 11.20

NaZO 4.75 5.42 5.36 5.57 4.38 5.09 4.96 5.03 5.01 4.59 4.54 3.11

K2° 4.48 4.09 4.45 4.28 4.86 3.71 3.18 2.76 3.79 3.05 2.46 0.89 Ti02 0.23 0.28 0.27 0.32 0.41 0.43 0.65 0.75 0.64 0.73 1.65 0.77

'2'5 0.05 0.05 0.05 0.05 0.07 0.07 0.15 0.20 0.15 0.22 0.41 0.24 HnO 0.04 0.08 0.07 0.11 0.06 0.08 0.08 0.09 0.1 0.15 0.19 0,17


Q 32.9 31.7 29.5 28.2 23.21 23.9 20.90 18.4 17.6 18.9 7.2 C 0.28 0.3 0.38 0.4 0.4

0 r 26.5 24.2 26.3 25.3 28.74 21.9 18.80 16.3 22.4 18.0 14.5 5.24

Ab 27.1 27.1 27.2 28.7 37.04 13.1 41.94 42.6 42.4 38.9 38.4 26.32

An 5.22 5.1 10.04 12.5 8.3 13.3 13.8 30.03

Me

U o 0.2 0.1 0.1 0.5 4.7 9.99

En 0.2 0.2 0.2 0.2 1.36 1.0 2.53 3.0 1.7 2.7 6.9 8.3 Fs 7.7 8.0 8.5 1.08 0.9 1.33 2.6 1.5 5.6 5.1 7.32

FO 3.5 Fa 3.01

M t 0.56 2.13 2.76 2.49 2.40 4.0 1.23 5.3 3.33 I 1 0.44 0.54 0.52 0.60 0.77 0.81 1.23 1.42 1.2 1.39 3.1 1.45

AP 2 0.12 0.12 0.12 0.16 0.16 0.36 0.47 0.35 0.51 0.94 0.57 . He 0.54 D i 0.0

AC 11.6

Modal crlcul at ions (percent volume

Plagioclase 34.4 41.7

Quartz 14.2 10.1 Ha f ic 7.5 6.9

minerals ,. , * .,.

Tota l 100 il;C ..... -

No LO1 spec i f i ed i n l a b report 14

Table 1--XRF chemical analyses. CIPW norms. and selected modes o f rock samples from the Peterrburg and parts of the Port Alexander and Sumdurn quadrangles, southeastern Alaska--Continued

Uni t Tmqk Tmgk Tmd k Tmgb I

Map No. 145 146 147 148 149 150 151 152 153 154 155 156 F i e l d NO. 79DG038A 800B043B 82SH0548 8ODBlllA 80RS051A 80DB049A 82SH053A 825H049A 80SK541A 82KR018A 80SK532A 800B190A

XRF chemical rna l yses (welght percent)

SiO2 48.59 47.5 73.8 73.2 72.2 71.6 68.9 51.8 57.8 56.2 54.6 49.7

A' 2O3 18.46 18.0 13.4 14.1 14.5 14.1 14.1 17.2 14.6 14.3 15.3 14.0

Fezof 2.25 2.23 0.96 1.51 1.13 1.18 1.32 2.0 4.62 3.65 3.99 2.1

FeO 7.51 6.83 0.97 1.26 1.52 1.51 3.03 7.3 3.61 5.40 7.21 9.87

'2O5 0.35 0.38 d0.05 <0.05 0.05 <0.05 0.11 0.18 0.15 0.16 0.87 0.35

MnO 0.19 0.29 C0.02 0.04 0.05 0.05 0.09 0.14 0.15 0.17 0.19 0.17

- --

Total 98.94 97.16 98.74 100.15 99.80 98.75 98.89 99.30 99-91 99.30 99.68 99-09

Oxides normal ired t o 100%

$to2 49.11 50.9 74.9 73.3 72.6 73.1 69.9 52.4 59.2 57.93 55.2 51.8

2'3 18.66 19.3 13.6 14.1 14.6 14.4 14.3 17.4 15.0 14.74 15.5 14.6

Fe203 2.27 2.39 0.97 1.51 1.14 1.20 1.34 2.0 2.61 3.76 3.49 2.2

FeO 7.59 7.32 0.98 1.26 1.53 1.54 3.07 7.5 5.61 5.57 7.79 10.28

CaO 11.84 6.08 0.51 1.10 1.55 1.08 1.M 9.19 6.32 6.37 6.49 8.06

- -

ClPU normative minerals

P 31.8 30.5 29.4 30.2 22.3 2.9 9.5 6.8 7.7 C 0.4 1.1 1.0 0.9 1.4

Or 6.57 9.6 24.3 21.5 19.4 20.6 18.4 2.8 10.8 9.7 9.6 3.7 Ab 24.07 36.4 37.5 37.6 38.1 38.0 43.1 28.9 34.0 38.7 33.8 34.1

An 33.06 27.5 2.2 5.1 7.4 5.0 7.0 30.7 17.4 14.8 19.5 19.9

Ne 1.83

Uo 9.75 0.7 5.7 5.4 6.6 2.9 7.4

En 4.9 1.7 0.4 0.0 1.0 0.9 1.6 12.7 10.2 9.9 7.1 11.0 Fs 4.63 1.1 0.5 0.8 1.5 1.5 3.9 8.7 6.6 5.6 8.5 10.4

f o 4.3 9.9 3.0

Fa 4.51 7.2 3.1

hit 3.30 3.47 1.41 2.19 1.65 1.75 1.94 2.9 3.79 5.46 5.06 3.2

I I 2.25 1.94 0.33 0.42 0.52 0.46 0.98 4.2 2.04 2.09 3.75 3.32

AP 0.82 0.94 0.12 0.12 0.12 0.12 0.26 0.42 0.36 0.38 2.04 0.84 He

Modal cat eulations (percent volume)

K-feldspar 3.4 31.0 33.0 Plagloclase 61.2 34.8 35.7 Quartz 28.0 25.6

Ha f ic 35.4 6.2 5.7 minerals

Total 100 100 100

+ No LO1 specified i n l a b report

Table 1--XRF chemtcal analyses. CIPU norms, and selected m!der of rock samples from the Petersburg and parts of the Port Alexander and Surndum puadrangles, southeastern Alaska--Continued

I

U n i t K*W

I h p No. 157 158 159 160 161 162 163 164 165 166 167 168 F i e l d No. 80SK443A 790B108A 79SK022A 79RS018A 7BOB2WA 79SK072A 80RS015A B0RS019A 800B077A 82SH0568 790B097A 82SH057A

XRF chemical rnalyses (wejght percent)

$to2 69.0 68.62 68.58 68.24 67.68 67.25 67.0 66.5 66.0 65.2 64.95 61.5

2O3 15.8 15.44 16.36 17.21 15.37 16.15 16.3 16-6 16.5 16.3 17.66 16.3

Fe203 1.45 1.52 1.05 0.76 1.77 1.81 1.90 2.06 1.94 1.84 1.66 2.33 FcO 1.40 0.94 1-10 0.90 4 1.25 1.66 1.36 1.87 2.02 1-45 3.29

ngo 1.20 0.71 1.2 0.51 1.29 1.01 1.51 0.91 1.65 1.65 1.39 2.20 CaO 3.99 2.83 4.14 4.16 3.61 3.48 4.60 3.67 4.93 4.85 5.44 5.93 Na20 3.85 4.62 4.0 4.81 3.19 4.79 3.56 3.72 3.58 3.80 4.33 3.42

K2° 2.28 2.75 2.46 1.31 3.49 2.62 2.50 4.27 2.56 2.35 1.32 2.70

Tota l 99.87 97.91 99.27 98.21 98.33 98.94 99.83 99.97 99.79 99-23 98.71 99.14


SiO2

A' 203

Fe203 f cO

HgO CaO

Na20

K20 Ti02

P205 MnO

ClPY normative minerals

- -.

Modal ca lcu l r t ions (percent volume)

Quartz 22.7 18.8 24.6 24.6 24.5 16.2 17.8 16.8 16.6 18.6 Maf ic 7.4 2.1 5.2 4.5 8.1 5.9 11.3 6.6 11.1

mi neral s - - --- -. . ---

Tota l 100 100 100 100 100 1 DO 100 100 100 - - .- .. --

No LO1 spec i f i ed i n l a b repor t .. +-

Table 1--XRF chemical analyses. CIPW norms, and selected modes of rock samples from the Petersburg and parts of the Port Alexander and Sundum quadrangles, southeastern Alaska--Continued

-- Unit Kwqo Ksm R hh -- Hap No. 169 170 171 172 173 174 175 176 177 178 179 180 F i e l d No. 79DB031C 82SH055A 79DB017A 7908033A 79DBO32A 79RS021A 79SH035A 800B086A 79DB091A 80SK447A 82SK046A 82SKO51A

XRF chemical anal yser (wef ght percent)

Si02 61.17 60.1 60.04 57.5 53.75 53.45 53.1 52.9 52.11 42.6 45.4 51.5

2% 17.75 17.0 17.39 18.08 17.87 16.07 17.72 18.9 19.69 17.8 18.0 17.9

Fe203 1.34 2.21 '2.97 3.75 3.29 4.51 0.40 4.54 3.50 7.92 1.65 1.76

FeO 1.81 3.63 2.53 3.03 4.83 5.17 7.77 3.85 3.64 5.65 7.44 5.56

- . -- --- - --

Total 99.80 99.26 99.40 99.56 99.29 99.27 96.79 100.33 98.75 100.20 99.03 98.94

Oxides normal l zed t o 100%

5102 61.29 60.8 60.40 57.8 54.13 53.84 54.9 52.9 52.77 42.7 49.3 53.7

*'z03 17.79 17.2 17.49 18.16 18.00 16.19 18.31 18.9 19.94 17.8 19.5 18.7 3 1.34 2.24 2.99 3.77 3.31 4.54 0.41 4.54 3.54 7.93 1.79 1.84

FeO 1 -81 3.67 2.54 3.04 4.87 5.21 8.03 3.85 3.69 5.66 8.08 5.80

Mgo 2.18 2.74 2.2 2.34 3.96 4.6 4.4 2.85 3.38 5.66 4.34 5.28 C ~ O 7.15 6.62 6.67 7.20 9.14 8.52 9.3 9.70 9.64 17.3 9.25 5.81

Na20 4.32 3.57 4.02 4.47 3.54 4.36 3.67 4.07 3.69 1.08 4.58 4.70

K20 3.17 2.23 2.75 2.02 1.74 0.87 0.46 1.59 2.25 0.22 0.33 2.47

T102 0.62 0.64 0.57 0.78 0.89 1.41 0.12 1.05 0.68 1.37 2.14 1.20

P2°5 0.22 0.16 0.22 0.27 0.27 0.23 0.26 0.38 0.27 0.09 0.50 0.35 HnO 0.10 0.13 0.12 0.19 0.15 0.19 0.13 0.21 0.15 0.19 0.14 0.13


H t 1.95 3.24 4.33 5.46 4.80 6.59 0.60 6.58 5.14 11.50 2.60 2.66

I 1 1.18 1.21 1.09 1.49 1.68 2.68 0.24 1.99 0.29 2.60 4.06 2.28

AP 0.51 0.38 0.51 0.63 0.63 0.54 0.6 0.88 0.63 0.2 1.16 0.82 He


K-feldspar 24.1 18.7 14.9 5.4 1.0 7.4 9.1 Plagioclase 49.7 55.4 66.2 55.6 60.6 55.2 58.2 62.0 53.6

Quartz 13.6 10.6 6.4 2.9 6.7 5.7 13.5 3.3 2.7 M a f i c 12.6 15.3 12.5 36.1 31.7 39.1 20.9 25.6 43.7

minerals

Total 100 100 100 100 100 100 100 100 100 -. -

No LO1 speci f led i n l a b report

Table 1--XRF chemical analyses, C I P W norms. and se lected modes o f rock samples from the Petersburg and par ts of the

Por t A l ~ x a n d e r and Sumdum quadrangles, southeastern Alaska--Continued

- Uni: R hh & k K t c f

Map No. 181 182** 183 184- 185 186 187 1Sa 189 190 191 192 F i e l d No. 78Aag127A 635192a-2 89SK599A EZA192a-1 78ABg129A 784891288 82SH009A 82SK038A 78ABg130A 78ABg131A 82DS099A 8ZPB087A

XXF chemical analyses (weight percent)

S i02

2O3

fe203 FeO

MgO CaO

na20

K20 Ti02

P2°5 HnO LO I

Tota l 91.35 97.72 99.66 99.73 94.92 89.74 86.99 98.57 97.17 95.72 99.12 98.61

Oxides normalized to 1002

FeO 2.54 4.80 7.52 9.54 9.13 2.65 4.66 8.22 0.53 0.72 2.51 3.76

CaO 4.67 4.36 8.82 11.30 4.39 12.26 16.17 14.9 0.12 1.51 3.59 4.69

MnO 0.07 0.07 0.13 0.17 0.33 0.13 0.16 0.16 0.04 0.16 0.07 0.09

CIPU n o m a t i we minera ls

Q 12.34 43.44 40.27 24.9 22.6

Modal ca lcu la t ions (percent ~ 0 l u m e )

Quartz 22.6 27.5

H a f i c 24.3 19.3 minerals

Tota l 100 100

. No LOI spec i f i ed i n l a b repor t .. Non-XRF ana lys i s - see Table 2

Table 1--XRf chemlcal analyses. ClPW norms, end se lected modes o f rock samples from the Petersburg and pa r t s o f the Por t Alexander and Suadum quadrangles, southeastern Alaska--Continued

K t e f U n i t -

b p No. 193 194 195 196 197 198 199 200 201 202 203 204 F i e l d No. 82SKlOOB 82RK777A 81PB032A 81RK319A 82KROOZA 8208205A 82PB106A 82D8198A 82PB0864 78flS097A 82SKO90A 81DBllaA

XRF chemical analyses (weight percent )

CaO 5.07 5.63 4.79 5.23 5.42 6.29 5.33 5.38 5.53 5.22 5.80 5.87

'2O5 0.25 0.30 0.24 0.25 0.31 0.33 0.22 0.26 0.27 0.23 0.31 0.33 HnO 0.08 0.09 0.11 0.12 0.11 0.10 0.11 0.11 0.11 0.14 0.14 0.14 LO1 0.44 0.62 0.70 0.50 0.45 0.31 0.41 0.59 0.46 t 0.34 0.29

To ta l 98.79 98.99 98.81 99.55 98.70 98.85 98.29 98.70 98.30 98.17 98.27 99.15


Si02 65.6 64.8 64.82 63.6 63.7 62.9 63.3 63.1 62.8 62.47 62.5 61.9

*l2O3 15.6 17.6 15.70 16.8 17.0 16.7 17,3 17.2 16.5 17.72 16.5 17.5

Fe203 0.39 0.45 1.47 0.90 0.88 0.54 0.47 0.68 0.61 1.11 0.62 0.93

FeO 3.83 3.36 3.70 4.20 4.27 4.30 4.25 5.10 5.05 4.08 5.38 5.07

HgO 2.67 1.69 2.46 2.42 1.72 2.88 2.37 2.41 3.04 1.95 2.82 2.20 Call 5.15 5.72 4.88 5.28 5.52 6.38 5.15 5.48 5.65 5.32 5.92 5.94

P2°5 0.25 0.30 0.24 0.25 0.32 0.34 0.22 0.27 0.28 0.23 0.32 0.33

HnO 0.08 0.09 0.11 0.12 0.11 0.10 0.11 0.11 0.11 0.14 0.14 0.14 - --

ClPSl nonnative minera ls

Fa

Mt 0.56 0.65 2.1 1.30 1.27 0.78 0.68 0.99 0.89 1.61 0,90 1.35

11 0.91 0.77 1.0 1.03 1.22 1.08 0.95 1.24 1.16 1.12 1.26 1.17

AP 0.59 0.71 0.6 0.58 0.73 0.78 0.52 0.61 0.64 0.54 0.73 0.77 He

Modal ca l cu la t i ons (percent volume)

K-feldspar 4.5 13.2 7.4 5.0 8.3 3.4 7.5

Plag ioc lase 42.9 38.6 42.3 44.0 47.8 41.7 48.3 56.5 51.8 Quar tz 27.8 22.7 24.1 26.0 20.9 16.8 23.0 14.7 22.8 Ma f i c 24.8 25.5 26.2 25.0 31.3 33.2 25.3 21.3 25.4

minera ls

To ta l 100 100 100 100 100 100 100 100 100

+ No LO1 spec i f i ed i n l a b r e p o r t

Table 1--XRF chemical analyses. CIPU norms. and selected *odds of rock samples from the Peterrburg and parts of the Port Alexander and Sumdum quadrangles, southeastern Alaska--Continued

Unt t Ktef I

Hap No. 205 206 207 208 209 210 211 212 213 214 215 216 F i e l d No. 82SH134A 82SK089A 82SK096A 82RK781A 82SK142A 82SK124A 81TM002A 76RS132A 82RK779A 78DB113A 82PB072A 82KR065A


S102 61.1 60.9 60.8 60.6 60.5 60.4 60.4 60.18 60.0 59.36 58.3 57.5

- 7

FeO 3.65 4.47 4.76 5.23 4.99 3.67 5.53 5.11 5.60 5.33 5.39 5.87

CaO 7.07 5.80 5.47 5.78 5.70 7.07 6.06 5.85 6.18 6.25 6.80 6.69

LOI 1.60 0.41 0.84 0.33 0.51 0.69 0.47 0.33 0.40 0.41

Total 99.05 98.66 98.26 98.23 98.24 99.32 98.86 97.88 98.23 98.26 98-54 98.02

Oxt des normalized to 100%

Si02 62.7 62.0 62.4 61.9 61.9 61.2 61.4 61.48 61.3 60.41 59.4 58.9

2O3 17.8 18.1 17.7 15.6 17.7 18.1 17.6 16.65 16.3 17.53 17.2 17.5

Fe203 0.64 0.95 0.80 0.50 0.74 0.88 0.35 1.18 0.66 1.05 1.20 0.92

FeO 3.75 4.55 4.89 5.34 5.11 3.72 5.62 5.22 5.72 5.42 5.49 6.01

MgO 1.48 1.79 2.40 3.21 2.71 1.95 2.73 3.08 3.70 2.96 3.44 3.42 CaO 7.25 5.90 5.61 5.90 5.83 7.17 6.18 5.98 6.31 6.36 6.93 6.85 Na2O 3.83 3.35 2.98 3.14 2.87 3.40 3.18 2.94 2.82 2.96 3.02 3.04

K2° 1.39 2.34 2.16 2.30 2.11 1.94 1.83 2.33 2.01 2.04 2.08 2.08

T i02 0.66 0.59 0.70 0.65 0.65 0.98 0.71 0.70 0.72 0.82 0.74 0.78

'2O5 0.44 0.26 0.27 0.30 0.23 0.47 0.28 0.31 0.30 0.31 0.30 0.33

MnO 0.12 0.16 0.13 0.11 0.14 0.11 0.14 0.13 0.13 0.14 0.17 0.13

CIPW normative mlnerals

Uo 2.5 0.0 1.2 1.7 0.2 0.96 1.4 0.44 2.1 1.6

En 3.7 4.5 6.0 8.0 6.8 4.8 6.8 7.68 9.2 7.37 8.6 8.5

Fs 5.5 6.9 7.4 8.5 8.0 4.7 9.1 7.72 9.0 8.00 8.2 9.2

Fo

Fa

M t 0.92 1.37 1.16 0.73 1.07 1.28 0.50 1.70 0.96 1.52 1.74 1.34 11 1.25 1.12 1.33 1.24 1.24 1.87 1.35 1.32 1.36 1.57 1.41 1.48

AP 1.02 0.61 0.62 0.69 0.52 1.08 0.66 0.71 0.69 0.71 0.68 0.76 He


K-feldspar 0.2 0.6 0.9 1.2 4.1 Plagtoclase 54.0 50.5 42.9 53.4 55.9 50.2 55.1 49.1 45.4

Quartz 16.0 23.9 24.0 14.9 24.3 20.1 15.3 10.2 12.0 Mafic 30.0 25.6 32.9 31.1 19.8 29.7 28.7 39.5 38.5

mt nerals .. - . -. - -- -- --

Total 100 100 100 100 100 100 100 100

No LO1 Specified I n l a b report

Table 1--XRF chemical analyses, C l P Y norms. and se lected modes *of rock samples froin the Petersburg and p a r t s of the

Por t Alexander and Sumdum quadrangles, southeastern Alaska--Continued

---- U n i t K t e f K t i f

Map No. 217 218 219 220 221 222 223 224 225** 226 227 228 F i e l d No. 82DB206A 78RM295A 82SK145A 82PB124A 82KR064A 830B189A 82PB12ZA 8ZPB003A 788G030A 78RSllBA 81DB129A 7938192A

XRF chemical analyses (weight percent )

Si02 57.4 56.72 55.2 54.7 53.7 53.2 48.9 61.7 61.4 61.32 60.9 60.90

A1 2O3 16.9 17.25 16.7 18.4 17.3 17.8 18.1 16.4 16.6 16.39 16.5 16.96

Fc203 0.65 2.59 0.69 1.11 0.81 1.09 4.3 1.89 1.4 1.23 1.09 1.46

FeO 6.11 4.82 6.40 6.85 7.18 7.54 5.59 3.19 4,5 4.62 4.62 4.61

3.98 2.92 3.51 3.29 4.88 3.90 4.12 1.79 2.2 2.26 2.83 2.44

CaO 7.85 6.53 6.44 7.78 8.03 8.71 9.99 5.28 5.2 5.07 5.78 K.19

Ha20 3.26 3.09 2.67 2.83 3.15 3.09 3.15 3.16 3.7 3.22 3.25 3.58

K2° 1.15 2.21 1.96 1.50 1.28 1.18 1.68 3.26 2.6 2.82 2.28 2.30

T i 0 2 0.66 0.65 0.77 0.89 0.79 1.04 0.83 0.50 0.61 0.62 0.58 0.59

P2°5 0.37 0.33 0.26 0.37 0.34 0.52 0.47 0.25 0.28 0.23 0.25 0.25

MnO 0.16 0.17 0.16 0.20 0.17 0.20 0.21 0.14 0.15 0.13 0.13 0.14

LO1 0.43 3.27 0.72 0.51 0.53 0.59 1.11 1.06 0.32 * - - - -- - -- -- -

Total 98.92 97.28 98.03 98.54 98.14 98.80 97.92 98.67 99.70 97.91 98.53 99.43

Oxides normal i r e d t o 100% -- -- . - -- -- .. - - -

S102 58.3 58.31 58.3 55.9 55-0 54.1 50.2 63.2 62.3 62.63 62.0 61-26

*' 2'3 17.2 17.73 17.6 18.8 17.7 18.1 18.6 16.8 16.8 16.74 16.8 17.06

Fe203 C.66 2.66 0.73 1.13 0.83 1.11 4.4 1.94 ;.4 1.26 1.11 1.47

FeO 6.20 4.96 6.75 7.00 7.35 7.67 5.74 3.27 4.6 4.72 4.70 4.64

90 4.04 3.00 3.70 3.36 5.00 3.97 4.23 1.84 2.2 2.31 2.88 2.45 CaO 7.97 6.71 6.80 7.94 8.23 8.86 10.26 5.41 5.3 5.18 5.89 6.23

P2°5 0.38 0.34 0.27 0.38 0.35 0.53 0.48 0.26 0.28 0.23 0.26 0.25

MnO 0.i6 0.17 0.17 0.20 0.17 0.20 0.22 0.14 0.15 0.13 0.13 0.14

CIPY normative mlnera ls

Q 9.8 11.24 10.3 8.0 3.6 4.4 17.1 14.2 15.87 15.2 13.40 C

Or 6.9 13.42 12.2 9.1 7.7 7.1 10.2 19.7 15.6 17.02 13.7 13.67

Ab 28.0 26.88 23.8 24.5 27.3 26.6 27.4 27.4 31.7 27.83 28.0 30.47

An 28.5 27.42 29.3 33.8 30.0 31.8 31.1 21.5 21.3 22.41 24.1 23.55

Ne Yo 3.6 1.52 1.1 1.3 3.6 3.7 7.0 1.6 1.3 0.73 1.4 2.38

En 10.1 7.48 9.2 8.4 12.4 9.9 7.7 4.6 5.6 5.75 7.2 6.11

FS 10.0 6.12 10.8 10.8 11.8 11.8 4.3 3.8 6.5 6.83 7.0 6.60

Fo 2.0

Fa 1.2

Mt 0.96 3.86 1.06 1.64 1.20 1.61 6.4 2.80 2.1 1.82 1.61 2.13

I 1 1.27 1.27 1.54 1.73 1.54 2.01 1.6 0.97 1.2 1.20 1.12 1.13

AP 0.87 0.78 0.64 0.87 0.81 1.22 1.12 0,59 0.7 0.54 0.59 0.58 He

Modal ca l cu la t i ons (percent vo luae)

K- fe ldspar 0.2 17.0 5.2 7.0 5.1 5.5

P lag ioc la re 44.2 48.8 47.2 43.1 46..0 34.7 48.6 52.0 49.0 51.0

Quar tz 12-4 6.2 10.8 14.8 6.0 28.0 18.6 17.0 20.5 15.5

Maf ic 43.4 44.8 42.0 42.1 48.0 20.3 27.6 24.0 25.4 28.0 minera ls .

To ta l 100 109 100 100 100 100 100 100 109 100

No LO1 spec i f i ed i n l a b repor t .. Non-XXF ana lys i s - see Table 2

Table 1--XRF chemical analyses. CIPU norms, and selected modes of rock samples from the Petersburg and parts of the Port Alexander and Sumdum quadrangles, southeastern Alaska--Continued

Untt K t i f Ktop I

Hap NO. 229 230 231 232 233 2 34 235 236 237 238 239 240 F i e l d No. 79RS174A 79RS188A 78BG039A 7906191A 82SH005A 82SH004A 78RH378A 78RH376A 82SH006A 82RK727A 82KR096A 82KR074A

XRF chemical analyses (wolght percent)

Si02 60.08 60.01 59.4 59.39 59.3 59.0 58.40 57.11 5 6 6 48.6 66.3 58.7

2O3 18.33 17-04 17.0 15.60 17.5 17.1 17.95 18.87 17.5 18.2 17.1 17.6

Fe203 1.86 1.23 2.4 1.57 2.21 2.32 2.37 3.05 1.92 3.4 0.27 1.01 FeO 3.68 5.15 3.3 5.23 3.61 3.86 4.23 3.24 5.01 6.69 2.66 4.79

- .

HnO 0.17 0.14 0.16 0.14 0.15 0.20 0.16 0.21 0.19 0.23 0.08 0.14

LO1 1.47 1.00 1.75 * 2.13 0.47 0.39 0.65

Total 99.38 99.14 98.70 98.12 99.22 98.94 99.21 98.00 99.03 98.36 98.49 98.97

Oxides normal i r e d to 100%

SiOZ 60.46 60.53 61.1 60.53 60.4 60.7 58.87 58.28 58.4 49.6 67.6 59.7

A1 2O3 18.44 17.19 17.5 15.90 17.8 17.6 18.09 19.26 18.1 18.6 17.4 17.9

Fe203 1.87 1.24 2.5 1.60 2.25 2.39 2.39 3.11 1.98 3.4 0.27 1.03 FeD 3.70 5.19 3.4 5.33 3.68 3.97 4.26 3.31 5.17 6.83 2.71 4.87

MgO 2.08 2.91 2.1 3.69 2.15 2.24 2.61 2.02 2.58 4.50 1.25 2.46

CaO 6.63 5.91 5.8 6.24 6.38 5.74 6.67 7.40 6.52 9.86 5.16 7.49

Ma20 3.57 3.31 4.2 3.11 3.31 3.71 3.91 3.70 3.70 3.52 3.65 3.15

%a 2.33 2.66 2.5 2.59 2.95 2.44 2.08 1.73 2.31 1.66 1.28 2.03 T i02 0.56 0.65 0.61 0.68 0.64 0.71 0.69 0.67 0.70 1.11 0.43 0.76

P2°5 0.17 0.26 0.29 0.19 0.29 0.29 0.27 0.31 0.36 0.58 0.14 0.46 MnO 0.17 0.14 0.16 0.14 0.15 0.21 0.16 0.21 0.20 0.24 0.08 0.14


nt 2.71 1.80 3.6 2.32 3.26 3.46 3.46 4.51 2.87 5.0 0.40 1.49

I 1 1.07 1.23 1.2 1.30 1.22 1.35 1.30 1.28 1.33 2.12 0.81 1.45

AP 0.40 0.61 0.7 0.45 0.66 0.67 0.84 1.35 0.33 1.06 0.63 0.71 He

Modal calculat ions (percent volume)

K-feldspar 5.3 5.5 9.6 11.6 10.1 3.5 7.4 4.6

P l a g i o ~ l a s e 54.8 50.7 39.7 45.1 50.6 57.3 58.9 53.6 47.8 59.5 53.1 Quartz ' 15.8 15.8 16.9 14.5 18.2 18.0 11.0 15.0 2.4 22.8 14.4

Mafic 24.1 28.0 33.8 28.8 21.1 24.7 26.6 24.0 49.8 17.7 27.9 mi nerr 1 s

Total 100 100 100 100 100 100 100 100 100 100 100

No LO1 speci f ied i n l a b report

Table 1--XRF chemical analyses, CIPV norms. and selected modes of rock samples from the Pctersburg and par ts of the Port Alexander and Sumdum quadrangles, southeastern Alaska--Continued

Unit top Ktoc Kqo P I

Map No. 241 242 243 244 245 246 247 248 249 250 251 252 F i e l d No. 820B103A 82PB125A 820B222A 82KA074C 8208236C 82PB098A 81SK135A 82PB100A 82RK806A 82SK129A 79AF141A 8 2 ~ ~ 7 1 0 ~ - -

~


5 i 0 2 58.0 49.5 65.8 62.5 61.4 61.0 60.9 60.1 55.3 63.1 62.39 61.6

2O3 17.3 17.6 17.5 19.5 17.3 15.3 17.5 17.9 17.2 17-4 16.01 18.2

Fez03 0.83 1.3 0.34 0.71 0.01 0.92 1.06 0.74 1.20 1.80 2.00 1.77

f eO 6.12 8.72 2.22 2.65 4.46 5.02 4.47 4.74 6.20 2.39 2.79 2.65

n9O 2.57 5.77 0.94 0.61 1.97 2.96 1.93 2.12 3.16 1.57 1.93 1.48 CaO 7.64 9.05 4.48 6.30 5.19 5.84 5.17 5.92 8.79 5.32 4.98 5.98

Ha20 3.24 2.41 3.66 3.81 2.93 2.69 3.32 3.08 2.95 3.76 4.04 3.69

K2° 1.34 1.49 2.87 1.87 2.67 2.61 2.36 2.32 1.15 2.38 3.12 2.08 T i02 0.93 1.15 0.47 0.38 0.68 0.86 0.52 0.71 1.22 0.39 0.56 0.41

'2O5 0.50 0.38 0.24 0.25 0.30 0.41 0.29 0.29 0.74 0-20 0.21 0.22

HnO 0.16 0.26 0.05 0.06 0.12 0.13 0.15 0.13 0.21 0.13 0.14 0.16

LO1 0.46 0.80 0.44 0.39 0.48 0.93 1.00 0.43 0.81 0.73 0.76

T o t a l 99.09 98.44 99.01 99.03 98.51 98.67 98.67 98.48 98.93 99.17 98.18 99.00

Oxides normal i r e d t o 100%

$102 58.8 50.7 66.8 63.4 62.6 62.4 62.4 61.3 56.4 64.1 63.55 62.7

A1203 17.5 18.0 17.8 19.8 17.6 15.7 17.9 18.3 17.5 17.7 16.31 18.5

Fe203 1.84 1.3 0.34 0.72 1.03 0.94 1.08 0.75 1.22 1.83 2.04 1.80

FeO 6.21 8.93 2.25 2.69 4.55 5.14 4.58 4.83 6.32 2.43 2.84 2.70

n!40 2.61 5.91 0.95 0.62 2.01 3.03 1.98 2.16 3.22 1.59 1.97 1.51 CaO 7.75 9.27 4.54 6.39 5.29 5.97 5.29 6-04 8.96 5.40 5.07 6.09 Na20 3.29 2.47 3.71 3.86 2.99 2.75 3.40 3.14 3.01 3.82 4.11 3.76

K2° 1.36 1.53 2.91 1.90 2.72 2.67 2.42 2.37 1.17 2.42 3.18 2.12 Ti02 0.94 1.18 0.48 0.38 0.69 0.88 0.53 0.72 1.24 0.40 0.57 0.42

'2O5 0.51 0.39 0.24 0.25 0.31 0.42 0.30 0.30 0.75 0.20 0.21 0.22 MnO 0.16 0.27 0.05 0.06 0.12 0.13 0.15 0.13 0.21 0.13 0.14 0.16

-- -- . - .. ...

C I P Y normative mfneral s

Q 12.4 22.1 18.0 18.4 17.6 16.7 15-3 10.3 18.4 14-50 17.0 C 0.8 0.4 0.9 0.8 0.3

0 r 8.0 9.0 17.2 11.2 16.1 15.8 14.3 14.0 6.9 14.3 18.78 12.5

Ab 27.8 20.9 31.4 32.7 25.3 23.3 28.8 26.6 25.4 32.3 34.82 31.8

An 29.1 33.6 21.0 30.3 24.3 22.5 24.3 28.0 30.9 23.9 16.64 27.4

Ne

M t 1.22 1.9 0.50 1.04 1.49 1.37 1.57 1.09 1.77 2.65 2.95 2.61

11 1.79 2.24 0.91 0.73 1.32 1.67 1.01 1.37 2.36 0.75 1.08 0.79

AP 1.17 0.90 0.56 0.59 0.71 0.07 0.69 0.68 1.75 0.47 0.50 0.52 He


K-feldspar 6.8 1.7 0.6 0.3 9.1 13.8 8.8 Plagioclase 44.7 49.8 59.9 52.2 55.9 52.0 55.8 43.9 52.3 Quartz 20.6 28.0 22.6 26.1 31.5 26.4 17.6 22.5 18.4 Haf ic 34.7 15.4 15.8 21.7 12.0 21.3 17.5 19.8 20.5

minerals

Total 100 100 100 100 100 100 100 100 100

NO LO1 Specjfied i n l a b report

Table 1--XRF chemical analyses, CIPW norms, and selected mode& of rock samples from the Petersburg and parts o f the Port Alexander and Sumdum quadrangles, southeastern Alaska--Continued

Un i t K ~ O V K t g ~ . -

Map No. 253 254 255 256 257 258 259 260 26 1 262 263 2 64 F i e l d No. 80SK148A 7BRH254A 81SH056A 80SK594A 82PB014A 78SH053A 82PB023A 78AF142C 78RS082A 7BRH258A 810B161A 82SK146A

XRF chemlcal analyses (welght percent)

Si02 58.9 58.58 58.2 57.3 57.2 57.15 54.1 50.8 66.08 64.33 53.3 51.4

A1203 18.2 17.73 16.8 20.0 18.1 17.99 18.2 18.44 16.45 17.41 15.4 16.6

Fe203 2.26 2.56 2.55 2.87 2.54 2.39 3.34 2.85 1.52 -0.67 3.3 1.4

FeO 3.40 3.41 . 4.22 2.93 4.18 4.07 4.95 6.47 2.04 2.46 7.37 8.36

n9O 1.90 2.30 2.58 1.75 2.47 2.57 3.52 4.11 1.35 1.32 4.01 3.90

CaO 6.76 6.62 6.48 7.61 7.48 6.98 8.53 8.06 4.49 4.27 7.28 8.50

Na20 3.54 3.68 3.44 4.11 3.53 3.51 3.36 3.09 3.18 3.51 3.89 3.59

K2° 2.31 1.82 3.22 1.81 2.04 1.52 1.54 2.80 1.88 2.80 1.55 1.07

Ti02 0.55 0.56 0.79 0.60 0.72 0.62 0.73 1.05 0.41 0 . 4 2.01 2.15

P2°5 0.24 0.26 0.39 0.29 0.34 0.28 0.27 0.45 0.16 0.19 0.46 0.83 HnO 0.20 0.15 0.18 0.22 0.22 0.19 0.21 0.16 0.08 0.07 0.19 0.16

LO1 0.81 0.56 0.63 0.50 0.58 0.49 0.41

Total 99.07 97.67 99.41 100.12 99.32 97.27 99.33 98.28 97.64 97.47 99.25 98.37

Oxjdes normal i zed t o 100%

CaO 6.88 6.78 6.55 7.65 7.57 7.18 8.64 8.20 4.60 4.38 7.37 8.68

Na20 3.60 3.77 3.48 4.13 3.57 3.61 3.40 3.14 3.26 3.60 3.94 3.66

K2° 2.35 1.86 3.26 1.82 2.06 1.56 1.56 2.85 1.92 2.87 1.57 1.09

T i02 0.56 0.57 0.80 0.60 0.73 0.64 0.74 1.07 0.42 0.45 2.03 2.20

'2'5 0.24 0.27 0.39 0.29 0.34 0.29 0.27 0.46 0.16 0.20 0.47 0.85

HnO 0.20 0.15 0.18 0.22 0.22 0.20 0.21 0.16 0.08 0.07 0.19 0.16

CIPU normative mineral s

0 12.4 13.05 9.1 8.4 9.6 11.90 5.7 29.00 21.63 3.8 2.1 C 1.44 1.33

0 r 13.9 11.01 19.2 10.8 12.2 9.23 9.2 16.8 11.38 16.97 9.3 6.5 Ab 30.5 31.88 29.4 35.0 30.2 30.53 28.8 26.6 27.56 30.47 33.3 31.0

An 27.4 27.12 21.1 30.9 27.8 29.65 30.4 28.7 21.74 20.46 20.2 26.6

AP 0.57 0.62 0.91 0.68 0.80 0.67 0.63 1.06 0.38 0.45 1.08 1.96 He

Modal cr lculat ions (percent volume)

K-feldspar 9.3 10.8 5.1 6.4 2.2 4.5 8.8 3.5

Plagloclase 53.6 47.7 56.4 52.5 46.2 58.0 49.0 48.6 44.8

Quartz 10.7 13.4 10.6 13.1 34.0 21.0 33.6 5.8 4.2 M a f i c , 26.4 28.1 27.9 28.0 48.2 21.0 12.9 36.8 47.5

minerals

Total 100 100 100 100 100 100 100 100 100

+ NO LO1 specified i n 1 . . :sport

24

Table 1--XRF chemical analyses. ClPU norms, and selected modes o f rock samples from the Petersburg and par ts o f the

Por t Alexander and Sumdurn quadrangles, southeastern Alaska--Continued

-- U n i t KqO Kdi Kmgf KS s -- Ks g --- -- -- Hap No. 265 266 267 268 269 270 271 272** 273+* 274 275 276 F i e l d No. 82RK712A 8ZRK725A 8DRS145A 8DSKS87A 805K128A 79SH113A 82SK144A 71ABqZ47 78AF127B 78AF127A 82KR055A 81SK1374

XRF chemical analyses (wel g h t percent)

Fd)

ngo CaO

Ha20

KzO Ti02

'2'5 MnO

LO1

Tota l 98.37 98.79 99.37 99.71 99.57 98.40 97.99 98.09 99.99 97.08 97.06 98.65


5 i 0 2

*'2'3

Fe203 FeO

n@ CaO

l a 2 0

KP Ti02

P2°5 HnO

CIPY nonnative minera ls

Modal ca l cu l a t ions (percent volume)

K-feldspar 3.5 12.1 6.9 3.7 8.0 8.9

Plagioc lase 44.8 36.7 48.6 48.1 38.3 39.5

Quartz 4.2 5.2 4.5 6.7 2.6 2.6

i4afic 47-5 46.0 40*0 41.5 51.1 48.8 minerals

Tota l 100 100 100 100 100 100 . = No LO1 spec i f i ed i n l a b repor t .. = Non-XRF analys is - see f a b l e 2

Table 1--XRF chemical analyses, ClPW norms, and selected modes of rock samples from the Petersburg and parts o f the Por t Alexander and Suadum quadrangles. southeastern Alaska--Continue:

- Vnl t Ks s Ks P Ku k Khb - Map. No. 277 278 279 280 2811* 282 283 284 285 286 287 288 F i e l d No. B2KR064B 83KR053B 82KR051A 78RM290A 7lABg260 80SKl50A 80SK58OA 78AF1976 81SK170A 7BAF146G BZRK708B 78CH308D

XRF chemical anaiyses (weight percent)

CaO 7.52 2.06 1.73 10.40 10.9 6.63 14.9 6.92 8.66 14.34 12.10 10.34

K# 0.21 1.09 1.90 1.98 0.64 1.41 0.28 1.19 1.86 0.29 0.75 1.10

Ti02 0.55 0.69 0.81 0.72 0.76 0.97 0.21 1-00 1.16 0.44 1.27 1.70

p205 0.24 0.15 0.16 0.34 0.29 0.25 c0.05 0.27 0.60 0.09 0.63 0.23

HnO 0.20 0.05 0.08 0.17 0.22 0.15 0.18 0.12 0.22 0.19 0.24 0.17

LO1 0.65 1.54 2.97 1.83 3.47 0.85 0.77 0.48 t

Tota l 98.52 98.58 98.61 97-16 100.00 97.59 100.11 98.00 98.61 95.51 99.00 97.37


Si02 68.0 64.2 64.4 50.05 51.6 51.4 48.6 56.57 49.2 50.22 44.9 44.52

A'203 12.8 18.3 18.2 15.50 13.4 16.6 1.70 16.35 16.1 5.03 19.9 14.96

re203 0.74 0.35 0.91 0.00 3.9 1.6 2.7 1.20 2.3 2.51 2.99 2.72

FtO 4.01 5.38 6.08 11.17 6.5 8.50 6.71 7.86 10.94 6.97 9.36 10.50

lgo 3.35 2.78 2.97 6.02 8.7 8.18 24.1 4.89 6.39 18.39 4.74 11.45

CaO 7.68 2.12 1.81 10.70 11.1 7.04 15.2 7.06 8.85 15.01 12.28 10.62

WaZO 2.18 4.78 2.54 3.25 2.8 3.73 0.28 3.44 2.34 0.82 2.93 1.94

K20 0.22 1.12 1.99 2.04 0.65 1.50 3-23 1.21 1.91 0.30 0.76 1.13

Ti02 0.56 0.71 0.85 0.74 0.77 1.03 0.21 1.02 1.19 0.46 1.29 1.75

P2c'5 0.25 0.16 0.17 0.35 0.30 0.27 0.05 0.28 0.61 0.09 0.64 0.24 WnO 0.20 0.05 0.08 0.18 0.22 0.16 0.18 0.12 0.22 0.20 0.24 0.17

Cf P;I normative minerals

+ = No LO1 spec i f i ed i n l a b repor t ++ - Non-XRF analysis - see Table 2

Table 1--XRF chemical analyses, ClPU noras, and selected modes o f rock samples from the Pctersburg and parts o f the Port Alexander and Sumdum guadrangl es. southeastern A1 a s ka--Continued

U n i t Khb ~ J s v Wss

nap No. 289 290 291 292** 293 294** 2 95 ** 296** 297** 298 299" 3 0 0 ~ ~ f i e l d No. 8ODBO35A 8106242C 821K708A 71ABg232 79081154 71ABg231 71ABg256 BUDD-001 71ABg230 79RS115A 71ABg229 71ABg242

XRF ~ h e m i c a l analyses (wei sht percent)

SiO2

2O3 Fezof FeO

Moo

CaO Wa20

K20 T i 0 2

p205 MnO

LO1

To ta l 98.01 98.06 97.87 99.88 96.16 100.23 100.00 100.14 100.00 92.77 100.24 99.58


CaO 13.2 13.3 13.1 8.0 8.47 30.1 11.0 12.07 11.1 10.21 13.1 8.9

Ya20 1.61 1.52 1.47 4.0 3.74 2.9 3.1 2.04 3.0 3.36 2.2 3.8

K2° 0.95 1.47 0.99 1.5 1.45 1.1 1.9 0.65 2.0 0.58 0.23 1.1

T402 1.51 2,25 2.24 0.6 0.91 0.78 0.85 0.77 1.00 0.82 0.49 1.7

P2°5 0.07 1.50 ' 0.05 0.2 0.10 0.12 0.43 0.23 0.33 0.08 0.08 0.53 HnO 0.22 0.38 0.18 0.2 0.18 0.22 0.21 0.21 0.21 0.22 0.22 0.21

CIW normative minerals

Q 4.5 0.99

* = No LO1 spec i f i ed i n l a b repor t ** - Non-XRF analysis - see Table 2

Table 1--XRF chemical analyses. CIPW norms, and selected modes Of rock samples from the Petersburg and parts o f the Port Alexander and Smdum quadrangles, southeastern Alaska--Continued

-- Unit nzgb k hv Tdr Tag fgdb I -. - - Map No. 301 302 303 304 305 306 307 308 309 310 31 1 31 2 F i e l d No. 825H008A 82SK00ZA 80SK153A 82KR070A A33125 82DB199A BZKR071A A52716 81DB215A 81SH066A 81SK235A 81fK243A

XRF chemlcrl rnal yses (ralght percent)

SiOZ 41.5 47.5 48.5 74.6 74.7 72.8 73.9 70.9 69.1 66.9

A1 203 14.5 16.8 13.4 13.1 13.5 15.6 14.1 15.2 15.5 16.2

Fe203 6.6 3.0 2.7 0.55 0.07 0.01 0.68 1 1 8 1.49 1.66

FeO 8.38 8.04 10.34 0.59 0.76 0.34 0.48 0.93 1.17 1.54

HgO 8.06 5.38 5.89 0.11 c0.10 0.25 h C 5

0.27 0.62 0.78 0.99

C10 11.7 10.6 10.50 0.19 rn 0.42 2.58 1.66 3.01 3.44 3.06 0

Na20 U 1.46 2.69 1.83 3.95 rn 4.28 4.78 3.43 3.42 3.50 3.40

K20 0.38 1.74 0.16 4.44 u 4.51 1.50 4.29 3.49 3.22 3.16

Tf02 1.68 0.83 1.87 0.02 <0.02 0.06 5 0.12 0.23 0.35 0.39

P2°5 0.15 0.60 0.18 (0.05 <0.05 C0.05 e0.05 0.10 0.15 0.17

MnO 0.24 0.23 0.17 cO.02 0.03 <0.02 0.04 0.05 0.06 0.07

LO1 3.48 1.33 2.35 0.71 0.35 0.31 0.18 0.34 0.38 0.23

Total 98.13 98.74 97.89 98.33 98.79 98.30 99.20 99.47 99.14 99.57

Oxi das normalized to 100%

s1o2

A1203

Fe203 FeO

HgO CaO

Nr20

K20 TiOZ

p205 nn0

CIPU nornative minerals

Modal c r l culat ions (pcrcent vo l we)

K-feldspar

Plagtoclase

Quartz

na f i c minerals

T o t a l 100 100 100 100

Table 1--XRF chemlcal analyses. ClPY norms, and selected modes of rock samples from the Petersburp and parts of the Port Alexander and Sumdun quadrangles, southeastern Alaska--Continued

. -

Uni t Tgdb TgdP Ttos

Map No. 313 314 315 316 317 318 319 320 32 1 322 32 3 324 F i e l d No. 81DB107A 81DB210A 81RK210A 78RM241A 78AF141C 810B106A 780B137A 780B248A 82RK796A 800B072A 8008242A 82SK107A


$102 63.1 70.7 66.0 66.13 61.17 61.1 60.56 58.97 58.6 58.5 58.5 58.5

A1203 17.3 15.0 16.4 16.36 16.78 17.4 17.33 17.27 17.7 18.2 17.6 17.7

Fe203 1.68 1.08 1.21 1.35 2.34 2.22 2.25 2.43 2.16 2.51 2.60 1.98

FeO 2.77 1.17 2.59 1.96 3.42 3.09 3.58 4.09 4.01 4.23 4.44 4.44

1.77 0.73 1.51 1.54 2.46 1.96 2.74 2.93 2.89 2.97 3.26 2.86

CaO 5.24 2.73 3.89 4.45 5.29 5.55 5.81 6.14 6.58 6.75 6.12 6.13

Na20 3.69 3.35 3.77 3.56 3.74 4.14 3.55 3.32 3.29 3.64 3.31 3.28

K20 2.10 3.59 2.54 2.04 1,59 1.98 1.77 1.70 1.77 1.56 1.87 1.91

Ti02 0.65 0.28 0.51 0.54 0.70 0.63 0.66 0.71 0.71 0.74 0.73 0.81

p205 0.26 0.11 0.20 0.18 0.34 0.33 0.23 0.27 0.26 0.29 0.24 0.25

MnO 0.08 0.05 0.1 0.04 0.01 0.12 0.11 0.11 0.11 0.12 0.13 0.11

LO1 0.46 0.22 0.26 0.59 t 0.40 0.26 0.70 0.51

Total 99.10 99.01 98.98 98.15 97.94 99.11 98.59 97.94 98.48 99.77 99.50 98.48

Oxldes normali2ed t o 100%

SiOz 64.0 71.6 66.9 67.38 62.46 62.02 61.43 60.21 59.7 58.8 59.2 59.7

A1203 17.5 15.2 16.6 16.67 17.13 17.66 17.58 17.63 18.0 18.3 17.8 18.1

Fe203 1.70 1.09 1.23 1.37 2.39 2.25 2.28 2.48 2.20 2.52 2.63 2.02

FeO 2.81 1.18 2.62 2.0 3.49 3.14 3.63 4.18 4.09 4.25 4.49 0.53

CaO 5.31 2.76 3.94 4.53 5.40 5.63 5.89 6.27 6.71 6.78 6.19 6.26

'2% 0.26 0.11 0.20 0.18 0.35 0.33 0.23 0.28 0.27 0.29 0.24 0.25

MnO 0.08 0.05 0.1 0.04 0.11 0.12 0.12 0.12 0.11 0.12 0.13 0.11

Cf PW normative minerals

Q 19.5 30.8 23.2 26.02 18.12 14.9 16.00 14.96 13.8 11.8 12.9 13.4

C 0.1 0.9 0.9 0.65 0.10 Or 12.6 21.5 15.2 12.28 9.59 11.9 10.61 10.26 10.7 9.3 11.2 11.5

Ab 31.7 28.7 32.3 30.69 32.31 35.6 30.47 28.68 28.4 31.0 28.3 28.3

An 24.6 13.0 18.2 21.29 24.53 23.4 26.50 27.77 28.9 28.9 28.0 28.5

nodal calculat ions ( w r c e n t vol me

Plagioclase 40.6 40.6 50.8 50.5 45.7 52.7 55.5 54.6 57.0 52.3

Quartz 24.5 30.8 24.2 28.2 20.3 22.2 17.8 13.0 12.0 21.7 Mafic 16.5 10.1 18.1 15.7 25.2 17.3 24.3 31.6 29.0 25.7

minerals

Total 100 100 100 100 100 100 100 99.9 100 100 - No LO1 specified tn l a b report

Table 1--XRF chemical analyses, CIPW norms, and selected modes o f rock Samples from the Petersburg and parts o f the Port Alexander and Sumdun quadrangles, southeastern Alaska--Contlnusd

- .. .

Map No. 325 326 327 328 329 330 331 332 333 334 335 336 F i e l d No. 81SK239A 81SK248A 810B253A 82SK216A 81SK123A 815K236A 79RS203A 8200195A 82KR066A 78RS092A 82SK122A 80SK609A


Si02 58.3 58.2 58.0 57.9 57.3 57.2 56.83 56.8 56.8 56.31 56.2 55.5

z03 17.7 17.0 18.2 17.8 18.3 18.1 17.71 18.4 18.2 17.92 17.1 18.4

Fe203 2.08 2.26 2.65 1.74 2.08 2.70 2.68 2.55 1.76 2.12 2.05 3.26

FeO 4.38 4.89 '3.91 5.24 4.46 4.38 4.44 4.50 5.20 5.13 4.99 4.76

LO1 0.56 0.55 0.36 0.49 0.27 0.40 t 0.33 0.46 0.35 0.29

Total 99.24 99.32 99.02 99.16 99.04 99.42 98.63 98.59 98.34 98.00 98.80 99.61

Ox$ des nomalt zed to 100%

Si02 59.1 58.9 58.8 58.7 58.0 57.8 57.62 57.8 58.0 57.46 57.1 55.9

A1203 17.9 17.2 18.4 18.0 18.5 18.3 17.96 18.7 18.6 18.29 17.4 18.5

Fe203 2.11 2.29 2.69 1.76 2.11 2.73 2.72 2.59 1.80 2.16 2.08 3.28

FeO 4.44 4.95 3.96 5.31 4.52 4.42 4.50 4.58 5.31 5.23 5.07 4.79

Milo 3.42 3.70 3.05 3.14 3.14 3.45 3.35 3.10 3.12 3.37 1 5 3.78

CrO 6.83 6.72 7.16 6.98 7.65 7.28 7.46 7.15 7.02 7.09 7.78 7.78

HnO 0.11 0.13 0.11 0.12 0.11 0.12 0.13 0.13 0.12 0.12 0.12 0.14

CIPW normative minerals

'I 12.2 12.9 13.3 11.8 11.2 11.3 9.0 11.4 10.9 8.91 8.0 8.9 C

H t 3.06 3.32 3.89 2.56 3.05 3.95 3.9 3-76 2.61 3.14 3.02 4.76

I 1 1.44 1.61 1.37 1.44 1.44 1.53 1.5 1.39 1.51 1.49 1.56 1.61

AP 0.56 0.63 0.61 0.66 0.89 0.68 0.6 0.66 0.66 0.66 0.82 0.72 He

nodal calculations (percent volume)

K-feldspar 1.5 0.41 0.7

~ l s ~ i o c l r s e 48.4 53.5 27.1 38.2 53.2

Quartz, 17.8 18.1 39.1 34.7 14.3

b f i c 32.3 28.0 33.8 26.4 32.5 mlnerals

Total 100 100 100 100 100

= No LO1 specified i n l a b report

Table 1--XRF chemical analysel, CIPU nnms. and selected modes o f rock samples from the Petersburg and par ts o f the Port Alexander anr3umdum quadrangles, southeastern Alaska--Continued

- Unit Ttos Todg TKbs TKhs

Hap NO. 337 3 38 339 340 34 1 Fie1 d No. 78RS066A 79D8225A 81SK159A 82UR0684 82KR071B

XRF cheml cal anal yres (we3 ght percent)

A1 2O 3 17.43 19.12 17.5 13.1 17.3

Fe203 3.55 1.49 1.91 1.9 1.02

FeO 4.26 1.95 4.06 12.10 6.74

Moo 3.04 1.18 ' 1.62 6.14 3.87

CrO 7.79 6.06 5.21 9.53 7.57

LO1 0.44 1.06 0.60

Total 98.09 99.33 99.50 98.13 98.49


Si02 54.01 62.53 62.2 52.6 57.1

A1203 17.77 19.25 17.7 13.5 17.67

Fe203 3.62 1.50 1.93 2.0 1. W FeO 4.34 1.96 4.10 12.46 6.89

HgO 3.10 1.89 1.63 6.32 3.95

CaO 7.94 6.10 5.26 9.81 7.73

NaZO 3.46 4.35 3.84 1.38 3.38

K2° 4.27 2.46 2.11 0.79 1.23

Ti02 0.79 0.41 0.76 0.79 0.72

"2% 0.51 0.13 0.32 0.09 0.12

HnO 0.18 0.12 0.20 0.24 0.26

CIPY nornative minerals

An 20.36 25.75 24.0 28.3 29.4

Ne U o 6.56 1.53 8.3 3.4

En 5.16 2.96 4.1 15.7 9.8 Fs 2.68 1.91 5.1 20.3 10.9

Fo 1.79

Fa 1.03

M t 5.25 2.17 2.80 2.9 1.51

11 1.51 0.78 1.44 1.51 1.36

AP 1.18 0.30 0.75 0.22 0.28 He


K-fel dspar 8.0

Plagiocl ase 65.0

puartz 14.0

Mafic 13.0 minerals

Total 100

* = No LO1 speci f ied i n l a b report

Table 2.--Petrographic d e s c - l p t l c ~ s cf am3le l o c a l l t i e s .

mp Sample Latitude nap Nmber Nuuber LondLude Pdadrangle :nit Sample d e ~ c r l p t i c n

--

Qb - Extrwive bara l t i c rocks and Imderlylng sedimentary rock? expored along scuthern shore of Kupreancf Ir land and cr! Hist!

C&-tle IFland i n Duncan Canal-Qllvine b - a t ; minor pymiene b w a l t . Fresh. ccmmonly in columnar jointed f lcus l e s s

th?L? 1 m thlck. Locally underlain by aa f l m . rnafic volcanlc breccia, cocglmerate. sandstone. and s l l t s t c n e .

Eqdvalent roe& be Included i n unlt P n .

1 BUDD-006 56°26*17w Pstwsburg Qb LabraZorlte Basalt--Consists of a m e h or p l a g l c c l ~ e l a t h with i n t w s e r t a l g r ~ ? d e r

1 33O34'25" 8-5 or grfmular a g ~ e g s t e or monoclinic pyroxene, p l a t e of ilmenlte. m a p e t i t e . s ? d

i n t e r z t i t l a l v y p t o v y a t a l l i n e areM. Pyroxene is much a l te red t o ch lor i te n d

c s r b n a t e . Hinor nmber of v e s i c l e ul th c a l c i t e , ch lor i te and quartz. nethod cf

chemical a n a l p i - not speclf led.

2 7 6 ~ ~ 0 5 4 4 ~ 6 ~ 3 1 * 3 5 " Petersbwp Qb Basalt--Hypocrystalline; rparrely plagloc1a.e p v p h y r i t i c . Croundmwr c o r ~ i s t s cf urr

1 33°05*56w C-4 oriented plaglocla*e l a t h s , r c s p k o w n intergranular augite. wlth i n t c r s e r t a l M N n

volcanic glass (up t o 12 percent). I n t e r s t i t i a l opaque-.. Mint? chlori te . Pyr i te

noted I n f i e l d .

3 71hBg179 ~ 6 ~ 2 8 ' 0 0 " Peterrburg Qb Olivine Bh-alt--Porphyrltlc with interlg.anular t o subophltic grom&=s. F w s t w i t i c

1 3 3 0 0 8 ~ 4 0 ~ 8-4 olivine f o m s L d d l n g s l t r r h a d g l m e r o c r p b . IntWgrcvn pa l rbrovn clinopyrcxrnt

and plagiocl&=e latL=,.. o l iv ine . cpaques. and llmenite make up tha moundaass. C W i d

analysis by rapid rock metmd.

4 71hBg178 56°28q48w Paterrburg ~b ol iv ine % ~ d t - - C l ~ e r ~ p ~ r p h ~ i t i ~ with i n t e r p a n u l u grounchass. ~ o r s t e r i t i c c l i v i n a

133007'42~ 8-4 f w a = g l m e r o c r p t a . Andeeine plagiocl&*e l a t b . i n t e r s t i t i a l greerrbrclm c l i n c p y .

roxene. ilmenlte. and r a n u l a r o l iv ine make up t t m groundmass. Milwr i d a i n E i t e altw- ation. Chemical analysis by rapid rock method.

56°27*04n Petmeburg ~b Olivine & s a l t - - ~ o l o t r y s t a l ~ l n e ; porphyritic. ~ o r m i r t s a mat OT l abrador i te p l a g i r

133'1 1 '30" B-4 c l a m laths. gram of clinopyroxene and ol iviee. 8nd minor i n t e r t t l t l a l palagorl te .

Accessmy m a p e t l t e and ilmenlte. hock i r f resh and i n outcrop exhib i t s f i s s i l e p la ty

r t r u c t w e para l le l t o flm. Hottmd of chemical analysis not specif ied.

6 79AF03lA 56°27'26m Petersburg Qb Olivine BP3alt--PorphyrltLc; sparsely g l c m e r o ~ r p h y r i t i c , wlth a p i l o t a x i t i c pclmd-

133'13*33" B-4 m&*s. Phenovysts of plaglocla-• and f o r s t e r i t i c ol ivine with iddingolte a l t e r a t i o n .

Groun6mass of andesine plagloclase and intergranular clincpyroxene alcng with accessory

opaque , secondary c a l c i t e , wangebrrrvn mica. and ChlOPlte.

7 71ABgl89 56'26'50~ P e t e r r w g PO Olivine ~ a s a l t - - ~ o r p h y r i t l c with l n t e r p m u l a r r o u n b w s . Anhedral t c subhe&-a1 for-

1 3??06q40' 8-4 r t e r l t l c o l iv ine p h e m w p t z i n a matt of c a l c i c andeslne plagloclase lathq. granular

climpyrcxene and o l iv ine , opaques, and minor vvlcanlc gla-s. Ulmr secondary

ca lc l te . Chemlcal analycls by rapid rock method.

8 79AF029A 56O26.34" Pe te rs twg ~b o l iv ine ~ s s a l t - - ~ o r p t t y ~ i t i c with ophl t ic t o s u m p h i t i c pomamms. F m t e r l t i c o l i v i n e

1 3P1o124" 8-4 forms phenovp%s and rparre glwerocrysts: c l f nopyroxene i s pol k i l l t i c . Grclxr.5a~=s

is or andesine t o labrador i te plsgioc1a.c la t - and i n t e r a t i t l a l cpawes. Uincr

idding?lte a l te ra t ion . S m p l e is fron volcanlc flow; contaiw up t o 5 percent vesicle!?.

9 82RK852B 56O27'09" Peterrburg Qb -salt--Porphyrltlc wlth p i l o t a x l t l c e~orrr.dm3zt. Andeslne plagloclaoe phenocryPtr w i t h

133°39'31" B-5 concentrlc zonlng; a l b l t e t u i m have clear rim.: and ra re ly include climpyrcxefle. M r t

cllmpyroxene is a l te red t c green m i c a and a c l t e . Grcundm-s ~ f i t a i n e up t c 10

percent opaques; seeendary ch lor i te and c s l c l t e in patch-. Masslve i f cutcrcp.

10 BUDD-002 . ~ 6 ~ 8 0 ' 3 0 ' Peterpbwg Qb Olivine Ba~alt--HclccryztaIllne; mmpoeed cf a groundm-: of s m a l latbz cf plrg:ccl-e

1 33c10'00* C-4 and mcnocllnic pyroxene wlth abundant accesscry minute grains of x a a e t ! t e and

i l aen i te . A crsJe flow s t ruc ture 1: prerent. N s z e r s , ~ phenccrygt? cf c l i v i r e xp t c

O.U mm. No a l te ra t ion . M e t h o d cf chemical wt.l?).?i? net cpe-if ied.

Table 2.--Patro@raphlc deac r lp t lons O r sample looalltlea--Continued.

- - -- - -- - -

M3p Sample Let l t ude nap Number llunber LonglLude Quadrangle Unlt Sample deao r lp t lon

QT r - Volcanlcs of mouthwest and sou th c e n t r a l Kupreanof I a l m d , rou thues t Zarembo I s l a n d rnd northwest E t o l i n Island--

Rhyol l te , rhyodac l t e and r e l a t e d a l l l c e o u s ex t rua lve and l n t r u a l v e rooks. Aphanltlo t o o r y a t r l l l n e , qua r t z and f e ldspa r

po rphyr l t l c , l o c a l l y layered. P y r l t e and z e o l l t e oommon. Stratigraphy includes l ava t lows, obsldlan f l o u s , a sh t u f f s

and dlklng. Local a r e a s of e x t r m e a l t e r a t l o n and brecola t lon.

11 82SK167A 56O32'27* Peteraburg QTr Welded Rhyol l te Tuff--Approximately 30 porcent dev l t r l f lmd # l a l a f l a m e In a matr lx of

133O31'47" C-5 c r y p t o c r y s t a l l l n a m a l e r l a l , d e v l t r l f l o d g l a a s , and dus t particles. Lenticular snaped f l m m e a r e l l n e d wl th psrpendloular alkali fe ldapa r growth, a p h e r u l i t e s , and qua r t z .

12 80080S6B 56°20'50* Pateraburg QTr Felalte--Very a t rong ly a l t e r e d . Approximately one-half of t h o t h l n s e c t l o n found

132°55'41n 8-3 t o c o n s i s t of reeondary c a l c i t e , chlorite, ep ldo te . and z e o l l t e s ( 7 ) . Re l i c t f e ld spa r

phenocrysts and a l t e r e d m l c r o l l t e s , l l n o r qua r t z , and opaques present . Sample from

d lke o r Tlow.

13 80SK537A 5b048'34* Peteraburg Qtr nlorogranlte--Very f l n e gra ined. Embayed quar tz : aubhedral t o rnhedrel p lagloclaae 1 33°45'19" D-6 phenocrysts In a matr lx of a l k a l i f e ld spa r - r l ch p s r t h l t e , mlcrOpWthl te , and QlCrO-

graphic t o granophyrlc qua r t z l n t s rg rou ths . Sparae rod-brown b l o t l t e p re sen t ; moder-

a t e amount of dus t and c l ay a l t e r a t l o n of p l ag loc l aae .

14 82DB18OA 5b027'39" Peteraburg QTr ~ n y o l i t e - - ~ i ~ r o u a Sphe ru l l t lC b l k a l l f e ld spa r -qua r t z m i c r o l l t s s with approximately 7

133O29*30" 8-5 percent annedral qua r t z patohes. Very f lne-gralned aparae blue-green mphlbole . Two

percent opaques and d w t . Outcrop of c o l m n a r f l o u s .

15 79SK178A 56O32*23* Petersburg QTr low-banded ~ h y o l l t e - - ~ r y p t o c r y s t a l l i n s t e x t u r e with t n i n veins of secondary qua r t z

1 33°29'06" C-5 p a r a l l e l t o t h e flow s t r u c t u r e . L l t t l e a e r l c l t l c a l t e r a t i o n . On an outcrop s c a l e t h e

rock e x h l b l t s a l t e r n a t l n g t h l n u h l t e and l l g h t green bands.

16 BB-uu 56'27'52" Peteraburg ~ f r ~ n y o l l t e - - ~ r y p t o e r y s t a l l l n e wi th t h i n aemndary qua r t z velna p a r a l l e l t o f l u x i o n a t ruc -

133O05'35" 8-4 t u r e . n ino r a e r i c i t l c alteration. Outcrop i a flow-banded u l t h alternating

t h i n u n i t e and l l g n t green banda. Method of cnemloal ana lya l a not a p e c l f i e d .

17 83DB199A 56°31'05" Petersburg 9Tr Welded tu f f - - I r r egu la r ml l l imeter-acale s t r e a k y lamlnat lons a r e deflned by brown g la s s -

133~33 '53" C-5 rlCh rlamme, c l e a r qua r t z , o r dust - r ich l a y e r s . Anhedral, a p h e r u l l t l c a t ruc -

t u r r s of qua r t z and f e ldspa r a r e ccinmon. Mlnor red-Drown b l o t l t e and very f lne-gralned

opaques. Most g l a s s l a d e v l t r l f i e d .

18 82SK180A 5b032'15" Peteraburg Qtr Rnyol l te tuff - -Eutaxl t i c . Banded. welded t u f f uonta lnlng p0 lyo ry5 ta l l lne qua r t z

133O32'05" C-5 a t r l n g e r s i n an a l k a l l f e l d s p a r , anhedral t o mlcrographlo dusty matr lx . ~ e s s tnan 1

percent c a l c l t e present a s l r r e g u l a r patches end r a r e l y e s l a n t l c u l a r q u a r t z cav l ty

l l n l n g .

19 83SKUl SC 5 ~ ~ 2 9 ' 2 0 " Peteraburg QTr Welded Turf--No t h l n s s c t l o n . F i e ld no te s lndl c a t e "sulphlae-bear lng, b recc l a t ed and 1 33°30'40v' 8-5 a p h e r u l l t l c welded t u f f . "

20 8308160 56O36'45" Peteraburg Q t r Welded t u f f - - I r r e g u l a r n l l l l m e t e r - a c a l t l a y e r s a r e def lned by brown d e v l t r l f l e d g l a s s ,

1 3 3 ~ 3 2 ' 34" C-5 dus t - r i ch , and qua r t z - r i ch l aye r s . Abundant qua r t z - r i ch aphe ru l l t aa i spa r se b l o t l t e :

ocinmon opaque dust..

21 BUDD-00) 5 ~ ~ 2 7 ' 0 8 " Peteraburg Q t r Rhyoll t e Porphyry--Groundmass m n s l r t ~ of m i c r o g r a p h l ~ ma a lc rog ran l t l c l n t ergrout hs

133O27'45" B-5 of qua r t z and f e ldspa r u l t h corroded phenocrysta of qua r t z and euhedral c r y s t a l s of

f e ld5pa r s . Mlnute g ra lns of magnat l te s c a t t e r e d t l rou#hout rook. Mlnor Seconddry i ron

a t a l n l n g . S m b a l l e r a t l o n l o c l ay minerals. Uelhod of chemical a n a l y s i s not

epeclf la t l .

33

Table 2.--Petrographic descrlpl lons of a m p l e localltles--Continued.

~ l e p Sample Lat l tuae nap Number Nunber Longitude Quadrangle Unlt, Smpl e deacr 1 pt 1 on

22 82Sl(l?8A 56°32115" Petmrlburg QTr Rhyollto Tuff--Uicroscoplc t s x t u r e uhlcn borders on flow-hnded r h y o l l t e t u f f and a

133O32'05" C-5 t r a c h y t l c microcrystal l ine turfaceous rhyolite. cannon quartz; l e s s common p o ~ y -

c r y s t r l l l n e quartz a t r lngers . Sparue, euhedral p lag loc l r s s phenocrysts occur amongst

rhnedral patcher or microcryatal l lne n lka l l fe ldspar . Abundant volcanlc ash; mlnor

i ron s ta in ing , and nemndary c a l c l t e present.

82SKll9A 56°32114* Petersburg QTr Rhyollte Tuff--Non-welded, Quartz and a l k a l i fe ldspar-r ich u l th mlnor secondary ca l -

133'31 '49" C-5 o l t e a s cavl ty l ln lng . Dtalnant t ex tu re l s s p h e r u l l t l c , Pyr l t e noted In outcrop.

79D6036A 56'35'47" Petersburg QTr Rhyollte Crystal Tuff--Soalc plagloclase occurs as glanerocrysts and broken indl-

133O42'26" C-6 vldual 6ralna. Matrix contr lns abundant mlcro- t o c ryp tocrys ta l l lna 8 l k a l l feldspar

and quartz alone wlth m a l l plaeloclase l a t b , accessory opaquas, and ausr , Less than

' 3 percent secondary o a l c l t o and a e r l c l t e .

83SKU67A 5 ~ ~ 3 3 ' 4 2 " P ~ t o r r b u r # QTr Rhyolite--Porphyrltlo wlth apnanlt lc d e v l t r l f l e d glassy matrlx. Flf teen percent PhenO-

133'27'44" C-s c r y s t s c o n a ~ s t of euhedral a l k a l i fe ldspar , scme a l b i t e , and mlnor quartz c r y l t a l s .

Small velns and pookets of secondary chalcedony, t r a c e of u h l t e mlca, and l eas than 1

percent opaques present i n rock. Sample from core of a l t e red zone.

83SK422A 56°35q13m Peteraburg mr ~ h y o d a c l t e ( 7 ) - - ~ o r p h y r l t l c w ~ t h euhedral t o anhedral plagioclase phanocrysts in a

1 33°32119w C-5 d e v l l r l f l e d glassy matrlx. Feu angular glassy fragments; a m e broken pnenocrysts;

rock looks fragmental. Sample from a dlke.

79DB133B 56°18'15n Peteraburg QTr Rhyolite--Plagioclaae porphyrl t lc with I r regu la r ly ahaped quar tz -ca lc l t e - f i l l ed amyg-

1 32°57t09n B - 3 dules. Groundmass of mlcrocrystal l ine a l k a l l f e ldspar , mlnor plagloclase, dus t , and

sparse d e v l t r l f l e d g lass . Approximately 5 percent secondary c a l c l t e , c h l o r l t r , and

wnl te mlca. Few secondary quartz ve ln le t s ; mlnor opaques.

82LRll JIA 56'33'31 " PetersbUrg Q f r Rhyodacl te--Porphyrl t l c r hyaloopll l t l c . Poor1 y twinned pleglocla3e forms phenocrysts:

133°1~0v18" C-6 m a l l l a th* In groundmass. Groundmass a l s o contains aburidant anhedral a l k a l l fe ldspar ,

cwmon quartz , and ween-brown d a v l t r l f l e d g lass . Trace of pyr l t e . Falr ly f resh .

83SKC22B 5b035'13" Peteraburg W r Obaldlan--Black-colored. banded and lpherul l t l c . Contalns aneular frapnents of brown

133O32'19" C-5 v o ~ c a n i c rock and unuelded g lass aharar .

83DBlu2A 56°311'37" Patarsburg QTr Rhyollte--Sanldlne pnenocrysts i n an anhedral mlcrocrystal l lne feldspar-quartz bearlng

1 33°34'46n C-5 ~rounltnass . Mlnor very flne-firrlned green-blue ampnlbole and common yellow-hroun Ilmo-

n l t e uealherlng.

03DB15lA 56O34'4En PotsPSbur@ QTr Obsldlen--Holohyallne pl tohstone wlth p e r l l t l c cracks. C r y a t a l l l t e s de l lne a flow

1 3 3 ~ 3 1 '43" c-5 Btru~LWe. Tan-colorad In t h l n sect lon; flve-meter-thlck rlow In Lhe f l e l d .

83SK410A 5b030'33" Petersburg PTr Dac l t l c (? ) Tuff--Dark green-gray hypocrystal l ine t u f f . Class matrlx encloses plag!o-

1 33O37 32" C-5 c lase and quartz pt~enocrysts , p l a g l o c l a ~ e n l c r o l l t e s . and 31n3ll rad ta t lng qusrr z-

feldspar gralns . Phenocrysts a r e Broken. No marlcs present.

8OSK536A 56°49112n Peteraburg QTr Rhyodaclts--Glmeroporphyrlt lc wlth ol lgoclase t o andsalnr plngloclase and nornblende

133°45'32n D-6 g l ~ e r 0 ~ r y ~ t 3 and phenocrysts along u l l h anal l e r Isolated blot l t e f l akes . Croundmrrr*

oans l s t s of mlcrocrystal l lne anhearal a l k a l l fe ldspar . scn t t e red quartz g r a l n 3 , and

mccesaory opeques. Thln secrlon 1s modarataly uenlhared.

83SKlrJbA 5 ~ ~ 4 4 ' 2 8 " Peteraburg QTr S l l i c l c Ye1 ded TurT--Contrl ns 40 percent feldspar ml crol 1 t es, 15 percant flow-rot at r d

1 33°34148" C-5 p ~ a g ~ o c l a s a phenOCry3ts. ano 10 percent o re u l t h i n I ~ghr-brown g 1 3 s r . C a v l t ies cun-

t a l n chalcudony.

Table 2.--Petrcgsphlc d ~ c r l p t l o n * of sample localltiel.--Contlrued.

mp Swple Latitude nap Wmwr Nmber Longitude Qmdrm.gle U n i t Sample deswiptlon

35 BUDD-008 56°32'05" Pctarburg QTr Quartz Klratcwyre--Hyalocrystalli~!e groundm~s w i t h a h y a l ~ p i l i t i c t ex twe traversed

1 33052'20w C-6 by a few I rac twer raced w i t h epldote. Euhedral phenoc-pts c m p r i l z g a b ~ t 5

percent by voluue. Crornbmass cah~lst-• of mlc ro l l t e w i t h a pronounmd rlou s t r u e

in a glass matrix. Pyroxene wmlderably altered t o calclte and to a slight extent

t c chlorite. Method of chemieal ana lp l a not specified.

36 835~415A 56'29-22* Petersburg QTr ~ a c i t e - - ~ y p o c ~ ~ t a l l ~ n e . Devitrlfied 81-r matrix swroun& rresorbed anheeal t o 1 33030'5'fw 0-5 subhedral plagloclam phenocryrtr 130%). ore (101). l r r e r i l s r mygdde f l l l l n w .

cllncpyroxene (5%). and rparse subhedral epidote. Outcrop it banded.

37 82PB067~ ~ 6 ~ 3 3 * 0 0 " Petarcburg Ptr AnOesltc-Porphyritic with a trachytlc woundms*. Fttecocrpts are andosine plagi- 1 33°42*44" C-6 oclase, hornblende. and sparse clinopyroxme. Groundmws contaiw mcstly a l lwed

plaglocliwe l a t b along with mmmon opaques and dwt. Minor zmo~mt cf remadsry

ca lc i te f r m plagloclase and ween mIca from pyroxene.

38 83DB139A 56w34'35" Petssburg QTr Andeslte(?)--Palcrtaxltlc with i n t c r a n u l a r t o $ubopnitle m.d glmercp2rphyritic 1 jp34 '08" c-5 climpyroxme. Plagloclme l a t h w e andeslne in cmposltion. Minor mount of

m i c r o ~ a p h l t i c p tasa i im fel&par. olive-brown biot i te , z u t t e r e d opaqes *.d re-

\ andary carbonate present i n th in section.

39 82SK175A ~ 6 ~ 3 0 ' 5 9 " Peterobufg QTr ~asalt--very tine- pained to cryptocrptall lne. Spsrrdy plagioclape p o r p h ~ i t i c 133040~11~ C-6 with an i n t c s ~ n n u l a r . but glare-baring. womdmas. Plaglocl=c m i c r o l l t r a r e

crudely orlcnted; opapucs we very abundant; clincpyrcxtne i s p reen t . ROuWy 10

percent dcvitrlf ied glasr, dust. and c r y p t o c r ~ t a l l i n e alteration.

40 82RK849A ~6~2'1 '24" Petmsburg QTr Baralt--Porphyritic with interwnnular and in temcr ta l grormQPas,.c. Fnemryl.tz 02

1 33°27'10" 8-5 calclc andesine plagioclme. t i t a c i w r i c h cllnopyroxene. and wall graim of

ollvlne. Grcunhaas of mn-oriented plagioclk-e miu -o l i t e . granular clincpy'rcxene.

cimmon opaquss, and devltrif ied glass.

21 83DB22lB 56O35*07* Petweburg Pfr Altered ~ a l t l A n ~ s l t e ( ? ) - - S t r o n g l y rl tcred. Abundant ealcic anbesine plagioclase

133O18*48" C-4 forms phenoctpts in an in terser ta l grcrmdmma. Both phenomyrts and p a u ' ~ ~ * s

contain zewndsry ptmpellyite. cnlorite. and cpidote.

42 78BM89C 56°16*15* Petcrebwg QTr Altered Basalt(?)--Strongly altored. Pwphyritic w i t h in terser ta l gro~Y1d6us. O r i -

132°56110m 8-3 ginal phenocrptr have t e n replaced by a plwchroic green-gcld mica. c h l w i t e . and

calcite. O t h s phenocrpb are sparse plagioclase. and altered olivine(?). Gromd-

m a 3 s of andesine microlltlrc, i n t s s t i t i a l wenullr palm of the above wem-gvld

ate-, clllorite al teration. and appoximately 7 percent opeque. Cha ica l analysis by

rapid rock method.

43 80DBO56A ~6~20'50m Petcrsbvg QTr Rhwdacitc(7)--Aphanltlc anhedral gsnular t o anhedral spharull t lc i n textwe. IF

132O55'47" 6-3 regular and spherull t lc patches of feldspar, quartz, and bevitrif ied g l s s . m e e

percent annedral polycrystalllne calcite patch-. Accrscry opaquep. Cryptowys-

t a l l i n e d w t common.

UTf - Vclcanlc e x t r u s l v r of ea-tern Kuiu and wc*terr: Kupreanof Islandr--Altered quartz l a t i t e . medim t o l!&?t g a y .

Contains microphenocrystic clinopyrcxene in plagioclwe poundma~s, with qusrtz. K-feldzpr, green b l c t i t e and

myrmekite. Intercalated with basalt and sanmtcne.

a4 79SK001E 56'31 '23" Petersburg QTf Ande~l t ~ - P c r m y i t i c with a pllotax: t i c pcmme. r . Ab-ndnnt sndec i~e pheT.CCCY?tr

1 33O53'1 8' C-6 alcng w i t h le? canmon orthopyroxene phenocry~b. RandcPly criented ~ ? d e I l r ! e miCrc-

l l t e ? , abuncant fine-gralned opaque?, and a p v s e gransular pyrcxene occ~," i n t h e

grOMaTkQP. S e ~ n d a r y mlnerale ( t c t d 5 percent) are l imcrlte, carX"3te rep1aeir.g

plagioclase, 3rd green-gold mica rep!scirg pyrcxene.

Table 2 . - -Pst rogaphl c desc r lp t lona of rample loca l 1 t i e s .

- S w p l e Let 1 tude nap Nukr Long1 tude Quadranglo Unit Sample dasc r l p t lon

8 2 ~ ~ 0 1 9 ~ 56°~8'09w Petersburg QTf Rhyodaclte(?)--Sparse p l ag loc l aae phenocrysts and c a l c l t e pseudornorphs of hornblende

133°45*59* D-6 ( ? ) a r e surrounded by anhedral t o aubhedral Intergrowtha O f p l8g loc l a s s , a l k a l l f e ld -

spar, and qua r t z . Trace of f lne-grained brown b l o t i t a I n p a r t a l t e r e d t o Ereen blo-

t lLe. Approxlmately 6 percent aecondary c a l o l t r , puupe l ly l t e , green b l o t l t e , and

c l ay mlnerals .

82KR020A 56°~8105w Petersburg QTf Rhyodacl te(?) - -Pwphyr i t lc , wlth a mlc roc rya ta l l l ne grom&nass of mlcroeraphlc and

133°45'54" D-6 granophyrlc a l k a l l f e ld spa r -qua r t z in tergrowths; t a b u l a r p l8g loc l aae , and minor

amounts of subequant cllnopyroxene and green-broun hornblende. Secondary c a l c i t e

and 1 lmonlte occur In mlnor m o u n t s .

QT a - Extruslve volcanica a t aOuth c e n t r a l Kupreanol I s l a n d , aouthwsstern hrernbo I s l a n d and t h e southern Rocky Paas area--

Ander l te . pyroxene and f e ldspa r po rphyr l t l c , masslve t o ves i cu la r and mygda lo lda l flows 10-50 cm t h i c k .

83SK475A 56°35140" Pateraburg QTa Andeslte--Porpnyrltlc; layered. Phenocrysts of 41 t e r ed p l ag loc l a se and qua r t z ,

133024*51n C-5 Contalns 1 percent py r i t e .

79DB027A 56°37'01n Petersburg QTa Andesl te-Pwphyrl t lc u l t h hya looph i t i c grounmass . P l ag loc l a se , c l l no - and or tno-

133°41 l25" C-6 pyroxene phenocrysts. Groundmaas w n t a l n s aubaligned andeslne and o l l g o c l a s e

m i c r o l l l e s , l n t e rg ranu la r cllnopyroxene, i n t e r s t l t l a l opaques, and up t o 4 percent

green-brown d e v i t r i f l e d g l a s s .

79DGO37A 56O36'2.6" Peteraburg QTa

1 33°43'U5vt C-6

79SH00bA 56°35'16" Peteraburg QTa

133°12q35w C-6

83D6209A ~ 6 ~ 3 2 ' 2 4 ~ Petersburg QTa

1 33'2ht1 3" C-5

83SK469A 56'35'27" Petersburg W a

133'24'52" C-5

Andeslte--Strongly a l t e r e d I n t h i n sec t lon . Po rpnyr i t l c wl th p i l 0 t a x l t l C groundmass.

R e l i c t p l ag loc l a se phenocrysts replaced by CalCl te , s e r l c l t e , and c h l o r l t e . Cround-

mass of n u b a l i g n e d p l ag ioc l e se m l c r o l l t e s a long wl th f ine-grained opaquea and r a r e

quar tz . Secondary mlnerals t o t a l t o 35 percent .

Andeslte(?)--Amygdaloldal; r t rong ly a l t e r e d . Approxlmately 3 percent c h l a r l t e / c a l -

o l t c - f l l l e d amy~du lea i n r groundmass c o n s l s t l n g of a l l e r e d u n a l i gned p l ag loc l a se

l a t h s , abundant opaques, s p a r s e qua r t z , and up t o 25 percent c a l c l t e and c h l o r l t e .

Basal t - -Porphyr l t lc u l t h l n t e rg ranu la r groundmass. Sparse p l ag loc l a se phenocrysts a r e

up t o 3 mra i n l eng th . Abundant l n t e r a t l t l a l olinopyroxsne and opaquer wl thln t h e

rndealne t o l a b r a d o r i t e p l ag loo la se groundmass. Co lo r l e s l t o pale green a c l c u l a r

amphlbole appears ascondary a long wi th approximately 5 percent green-broun cllnopyrox-

ene a l t e r a t l o n mlneral.

Baaa l t - -Pwphyr i t l c wlth nya looph l t l c rnd In t e rg ranu la r g r o u n h a s s . P l ag loc l a se pheno-

s r y s t s up t o l cm In l eng th wlth groundmass o r andeslne t o l a b r a d o r l t e p l ag loc l a se , in-

t e rg ranu la r cllnopyroxene, s p a r s e o l l v l n e , and common opaques. Minor amount of

d e v l t r l f l e d g l a s s .

Basalt--Holocrystalllne; porphyr l t i c u l t h a p l l o t a x l t l c p-oundmasa, Broken p l ag loc l a se

phenocrysts. Groundmass m l c r o l l l e s ln tergroun u l t h amphlbole and opaques. Rock 1 s

f r e s h ; D ~ J s ~ v ~ i n outcrop.

gfb H a l l c eXLru9lve rock3 or nar theas t e rn Kulu I a l and extendlng t o western Kupreanof I s l and . Also exposed on northwestern

Zlrmt-3 IalanO--Basalt . p l a t y , Dlocky o r Qnlmnar Jo ln t ed f lows 50 cm t o s eve ra l meters t h i ck . Cmmonly vesicular and

Imygdaloldal; amygdule f l l l l n g a Include c a l c l t e , ep ldo te . chalcedony, c h l o r l t e and zmol i tes .

82KR005A 56O30'57~ Peterabur@ QTb Obsldian--Dmlnantly p e r l l t l c a l a a s wlth partially d e v l t r l f l e d pale-broun s p h e r u l l t e s

133~33 '36" C-5 ' and a c l c u l a r m l c r o l l t e s . One plagloclaae phsnocryst and few q u a r t z - r l l l e d , spheru-

l l t l c - r lnmed cavl t l e ~ In t h l n s e c t Ion. Accessory opaques. Black and buf l - co lo red ;

banded i n outcrop.

Tabla 2.--Potrographlc deacrlpt lons of aample looalltles--Continued.

Map Smple Latl tude nap Nwnber Nunber Long1 tude Quadrangle Unl t Sample deacrl pt 1 on

55 83DB170A 56°42'00u Peteraburg QTb Anderlte--Andrslnn plagloclaae and ol lnopyroxenb pOrphyrltlC u l t h a pl lotaxi t l c

1 33'36 '00" C-5 groundmass of plagioclase a l c r o l l t e s and flne-gralned cllnopyroxene and opaqucs.

Phenocrysts form r a r e glomarocryata. Few ohlorlte/celrdonlte-filled a m y @ ~ ~ ~ l e s present.

56 62DB277A 56°36'48" Peteraburg 0Tb Andeslte--Porphyritic wlth t r achy t lc groundmass. Phrnwoyato a r e ol lgoclase t o ande-

133"40'29~~ C-6 r l n e plagloclrse ( r i m e d by l eas c a l c l c plagloolase) , c l l n o p y r o x ~ n r , r e l l c t htrrn-

blonde( 71, m a opques . a l igned aroundrnasr omposed most1 y of plaglocl ase alone wlth

l n t e r a t i t l a l granular cllnopyroxene, fine-gralned opaques, and dkvl t r l f l e d glass .

Moderate amount of secondary green mlca, l imoni t t , and ( 7 ) punpellylte (up t o 10

percent.

6 0 ~ ~ 1 8 4 ~ ~ 6 ~ 3 4 ~ 0 8 ~ Petereburg g to ~ n d e s ~ t e - - ~ o r p h y r l t ~ c . Phenocrysts or andeslne t o l abrador l t e plaeioclase along w ~ t n

133O4ow44" C-6 l e s s tnen 2 percent cllnopyroxene. Par t l a l ly glassy; h y a l o p l l l t l c wnundmars dominated

by non-wlented plagloclrse l a t h s . Interstices f l l l e d u l t h opaque3 (up t c 10 perccn:).

a l t e red g lass , and granular clinopyroxene. Up t o 2 percent c a l c l t e a l t e r a t l o n .

8 0 ~ ~ 1 9 8 ~ 56°37'56u PeterlDurg QTD ~asalt-~ndes~te--sparsel y plagioclase and clinopyroxene porphyrl t lc with a p1lotax:tic

1 33°46'51n C-6 poundmass of ruborlented mlcrocrystal l lne plagloclase uhlch l a subophlt lc wltn

granular cllnopyroxene. I n t e r s t l t l a l opaques up t o 10 percent. Flowbanded I n

outcrop.

82KR117A 56'34122" Petersburg QTb Basalt--Hyalopllltlc. Won- al igned p a r t l o l l y a l t e r e d p l a ~ l o c l a r e mlc ro l l t e s a r e aep-

133'41 *09" C-6 aratad by abundant very fine-gralned cllnopyroxene, abundant Opaque3 (up t o 10 per-

cent ), and a t r a c e of orange-brown secondary mica. Dwt, d e v i t r l f l e d g lass , and a

t r a c e of c a l c l t e a re present.

780523911 56°30'48" Petersburg Otb Basalt--Fine-gralned andesine plaglocla,e l a t h 3 a r e dwlnan t ly subophlt lc ; l e9s con-

133'54 '51" C-6 monl y intergranular u l th clinopyroxene. Approximately I percent l n t e r s e r t a l

dev l t r l f lud g lass . Accessory opaques; t r ace of calclLe present . Sample from

3-mete r - th lc~ amygdaloldal flow.

8JSKu13A 56°29'19N Peteraburg QTD Basalt--Hypocrystalline porphyrl t lc . Phenocrysts wnslst of 6 percent subhedral t o

1 33°30q00'1 B-5 anhedral plaeloclasu u l th reac t lon rims, 1 percent euhedral clinopyroxene. and 1 per-

cent o l l v l n e ( ? ) . CrounOnass Includes aligned, f e l t e d plaeloclase m l c r o l l L e ~ , up t o

3 percent ore. and 30 percent l n t e r s t l t l a l glass .

79DC041A 56°35s3~* Peteraburs 070 Basalt--Hyp~cry9ta11Ine u l t h t r achy t lc t ex tu re . Approximately 50 percent c rys ta l -

1 33°49'30w C-6 l l n e u l th 2 s l z e populatloru of plagloclase, l e s s tnan 5 percent clinopyroxene; 10

percent opaq~res. Volcanlc glaa3 i s p a r t l a l l y d e v l t r l f l e d and contalns In te r s t l t l a l

crypLocryatalllne maler lal . Trace of carbonate present.

82RK719A 56°42'18" Petsrsburg QTb Basalt--HypocryslallIne: t r achy t lc . Clinopyroxene and plagloclase form sparae pheno-

133°24t~91p C-5 crys t s in 811 Rncn mairlx or small andeslne p l a g ~ o c l a s e l a t h s and l n t e r s t l t l a l glays.

Opaque3, and cllnopyroxene aggreglteu. Up Lo 10 percent d r v l t r l f l e d glass and a l l e ra -

t ion .

19DB029A 56°38'16' Petersburg QTb Basalt--Porphyrltlc u l t n an Intergranular and I n t e r s e r t a l g rounhass . Sparse labra-

1 3 3 ~ 4 1 '59" C - 6 dor l l e p l a g l o c l a ~ e and r e l l c t o l l v l n c ( ? ) phenocrysts In A groundmass o t labradcrlr t . l o

andeslne pla#loclass l a t m , flne-gralned cllnopyrorene, and opequea. Approxl-

melely 5 percent a e v l l r l l l e d glass .

E3DB196A 5b031'48" Pett.r.burg OTo Basalt--Trachytlc u l t h ml nor amount of d e v l t r l f led g lnss , Plagloclese l a ths rengc I n

133°37'32" C-5 cmpus l t lon from sodlc andcslne t o labradorl le . Intergranular cllnopyroxene I s Of

moder~att abundance a:, a re opdqueo. Flou lamlnat Ions a r e dullned by Iron atainlnrr.

t a b l e 2.--Petrogaphlc d s ~ c r l p t l o n s of a m p l e localltles--Contlnuad.

Map Sample Lat i tude Hap Nunber Ntunbcr Longitude Quadrangle Unlt S m p l e daacrl pt 1 on

6 t 82PB132A 56°35n53* Petersburg Q T ~ Altered ~ a r a l t - - ~ o r p h y r l t l c with a p l l o t a x l t l c grounmass. Sparse plagloclase phen-

133O38'16" C-5 ocrysta up t o Z mm In length a r e rurrounded by partially orlenled andeslne t o labra-

d n r l t e plagloclase l a t h s and abundant granular opaquoo. Rellct cllnopyroxene and

o l lv lne(7) replaced by green-gold mlea (ch1orophmolt~)r chlorlLb, and c l lnozo la l t e

form over 20 percent of t h i n rec t lon .

82PB139D 56O33'43" Petersburg QTb Altered Basalt (7)--Porphyrl t i c u l th flne-gralned p l l o t s x l t i c woundmass. Pheno-

1 3 3 ~ 5 1 'OS* C-6 c r y s t s t o t r l l y replaced by recondary c a l c l t e and r e r l c l t e . Posslble amygdulesi up

t o 3 percent recondary quartz present. Secondary mlnerala t o t a l up t o 40 percent.

82SHOl3A 56°311'06* Peterrburg QTb Basalt--Subhsdral plegloclase phenocrysts occur withln a very fine-gralned t rach-

r 33°22q10w C-5 y t ~ c groundmass. I n t e r s t 1 t l a l clinopyroxene, abundant opaque3 , and rparse ol lvfne

present In groundmaas as a r e eh lo r l t e . d e v l t r l t l e d g lasa , and r a r e c a l c l t e - f i l l e d

IvnygduleS.

82SK168A 56°33915n Petersburg QTD Altered Basalt-- ~ o r p h y r i t i a with p l l a t a x l t l c groundrpasa, Phenocrysts a r e l a t r a -

133'39' 19w C-5 d o r l t e t o andeslna plegloclrse up t o 4 ma In length along wlth r a r e cllnopyroxene.

Crudely or lented flne-gralned plagloclase l a t h s d m l n a t e the grouncha9s. Abundant

opaques. Seoonaary c a l c l t e and oh lor l t e a re abundant.

83D8200A ~ 6 ~ 3 8 ' 5 4 " Peteraburs PTD Basalt--Amygdaloldal; sparsely plagloclase porpnyrl t le wlth an l n t e r a e r t a l ground-

133°32'3~* C-5 mass. C s l c l t e - f l l l e d my@dulea comprlse up to 15 peroent Of t h l n sect lon. S e r l r t e

andeslne plagloclaae l a t h s , abundant opaques and abundant l n t e r s t l t l a l d e v l t r l f l e d

g lass make up rmalnder of rock.

QT c - Volcanlclaat le Deposits--Pyroclastlc deposits, t e l s l c t o mafic tu f f and l ahars , ash deposits, and ol lgomlet lc

c o n g l a e r a t e s . Deposlts l a p onto volcanlc centers, a r e intercalated with extruslve rocks. and range frcm th lck ,

masslve, matrlx s u p p r t e d t o well-bedded m.-acale graded and upuard-flnlng beds.

BUDD-007 ~ 6 ~ j 6 ~ 3 0 ~ Patersburg OTc Andesi te--Pl lotaxl t lc t ex tu re with mlnor i n t e r s t i t i a l glass . PlaglOClase occurs

133~52'26" C-6 mostly a s mlc ro l i t e s , but l a t h s up t o .5 mm a r e common. Alao common a r e mlcroscoplc

gralna of mono~l ln lo pyroxene and magnetite. Method of chemlcal analysls not

sptrclfied.

7 2 79DGO4OA 56°36152" Petersburg PTC Altered b s a l t - - s t r o n g l y a l t e r e d , porphyrl t lc , and amygdaloldal. Groundmass of pllo-

133°4~143n C-6 t a x i t l c plagloclase mlcrol l tes . approximately 5 percent opaques, and up t o 25 percent

secondary oh lor l t e . c r l c l t e , epldote, and p w p e l l y i t e ( 7 ) .

73 8 0 ~ 0 1 7 5 ~ ~ 6 ~ 3 9 ' 4 7 " Petersburg PTC Altered ~o lcan la - - s t rong ly a l t e red . One phenocryst replaced by mlcrocrystal l lne

1 33P53140v1 C-6 quartz and c a l c l t e . Flne-grained plagloclase-rlch groundmass I s p l l o t a x l t i c .

Seven percent opaques; 50 percent aecondary c a l c l l e and I n l e r s t l t l a l quartz present.

7 4 BORSOAlrA ~ 6 ~ 1 5 ' 2 2 " Peteraburg QTc Besalt--Porphyrltlc wlth i n t e r s e r t a l groun4nass. Plagloclase phenocrysts u p t o 1

133O54'52" D-6 mm In length occur as sparse g lmerocrys ta In a groundrnass of l abradcr l t e plagio-

a lase l a t h s and l n t e r s t l t l a l green-brorn d e v l t r i f l e d gla33. Seven percent opaques.

€1 ght percent recondary c a l c l t e .

mo - Dikes, ~ 1 1 1 8 and extrualve rocks west of Trrreemlle Arm on Kulu Ialand and on Conclwlon and Zarembo Island9--Extremely

c a p l l e a t e d , heterogenous dlke3, flows, a l l l a and brecclas ranging i n cmpos l t lon f r m baar l t t o rhyo l l t e . Some

xanollths of matmorphlc country rock.

15 79D81211 5 ~ ~ 2 0 ' 5 3 " Petersburg 'PTP ~ h y o l i t e - - ~ o r p h y r l t ~ c . Euhedral a l b l t e t o ol lgoclase plagloclase phenOCrySt3 along

132°48109" 8 - 3 ui tn a few r e l i c t nornblende(7) phenocryst-s in a microcrystal l lne anhedral ground-

mas3 or potasslum fe ldspar , plagloclase. and small I rregular patchrr and vein3 o l

quartz. Moderate c a l c l t e and mlnor a e r l c l t a a l t e r a t l o n of phenocrysts.

Table 2.--Petrographic descrlpt lons of s m p l e localltles--Continued,

Sample Lat 1 tude nap Nunbsr Lonsltude P u a d r ~ n g l e Unit Sample descrlpt lon

- -

82sn009c 56°27'~8n Potarsburg QTd Rhyolite--Spt#erulltloi porphyrl t lc . Abundant phenoorysts of potasslum fe ld rps r an0

1 32°56"35n 8-3 p l s ~ l o c l a s e ; oommon ~ l k a l l faldspar-qudrlz spharu l l t ea In a maLrIX of d w t y al kal l

f e ldspar , quar tz , and few Opaquba. Secondary a l t e r a t l o n , up t o 7 percent. lncludes

white mloa, c s l o l t e , and Dhlarlta. Sample Worn 6-meter-wlbe Olke.

780V040A ~ 6 ~ 3 1 ' 5 3 " Peteraburg Otd Rnyodaclte(7)--Pwphyrltlc u l t n a p l l o t a x l t l c grounaPasa. Phenocrysts of ol lgoclass

133O52'05~ C-6 plagloclase, aanldlne, ollrwrpyroxent, and Iron-rlch 01 1 r lne. Grour~dmass l a a mlcro-

d r y a t a l l l n e Oomblnatlon of feldspars and quartz . con ta lm elongate and granular

cllnopyroxene, and sparse opaques. Sparse aeoondary c a l c i t e present.

79DG035A 56°35'10n Poterrburg QTd Altered Andeslte(7)--Porphyrltlc with p l l o t a x l t l c groundrnass of ol lgoclase t o mdc-

133O05' 30" C-6 s lne plagloclaae l a t h s , I n t e r a t l t l a l quartz , and flne-gralned Bubhedral opaques.

Plagloclaae phenocrysta contaln secondary o a l c l t e and mlnor s e r l c l t b . Small quartz

phenocryats a re polycrystal l lna. Chlorl te occurs along u l th c a l c l t e as mygdula

fillings, In the grounanass, and aa small c l o t s .

82SH009A 56°27'08" Petersburg P7d Altered volcanic--Pwphyrl t l c u i th p l l o t a x l t l c groundmass. Phenocrysts of a1 bl t l zed

132O56'35*@ 8-3 plagioclese; poaslbl y 1 re1 ~ c t aug i te g r s ln In t h l n sect lon. Grounclmass of unorlented

plagloclase l a t h s , roughly 5 peroent opaquea. and mlnor l n t e r s t l t l a l quartz. Strongly

altered--over 15 percent secondary c a l c l t e and c h l w l t e present. Part of dlke complex.

BOSKu72A ~ 6 ~ 3 5 ' 0 7 " Port Alexander QTd Greenstone--Reurystall!zed mIcrodlorl te(?) . Subophltlc a lb l t l zed plagloclase u l th

1 3 ~ ~ 0 5 ' 0 3 ~ C-1 p a r t ~ a l l y rec rya ta l l l zed hornblende, ~ n t e r s t i t ~ a l quartz , and accessory magnetite.

Secondary ec lcu la r amphibole occurs throughout along u l th c h l o r l t e , c a l c l t e , and mlnor

o l lnozo l s l t e .

BUDD-005 56°28'26" Petersburg QTd Andeslte--HyalocrystallIne u l t h nya l0p l l I t l0 t ex tu re and a pronounced flow s t ruc tu re .

1 3 3 ~ ~ 9 ~ 0 9 ~ 0-6 Consists of mlcroscoplc l a t h s of plagloclase, And numerous grains and rods of mono-

c l l n i c pyroxene In a glass grounhaas. Skeletal rnagnetlte and I lmenltc plates occur

i n the glaaa. Method of chcmlcal an3lysls not spuclf lad.

82SH061A 5b031*YbW Peteraburg Qtd Altered volcanic--Pllota%ltla. Subheoral, dusty plaeloclese l a t h s and r o s e t t e s and

133~46'37" C-6 prlmary quartz occur wtth l n t e r a t l t l a l secondary ch lo r l t e and c a l c i t e . hccessory

opaques. Pyr l t e noted In tne f i e l d . Over 30 percent aecondary mlncrals.

BU0D-004 5P31198" Petersburg QTd Basalt--HOlocrystallIne t ex tu re ; m n s l s t s of plagloclase l a t h 3 in a groundmlss cf

1 3 3 ~ 4 0 ' 10" C-6 a l t e r e d ferrmagnesian mlnerals with abundant mlnute gralns of neenet l t e and plat cs

of i lmenltr . Alteral lon products consls l of c h l o r l t e , epldote. and a l l t t l e

carbonate. Plagloclaae 1s In part a l t e red t o epldote and carbonate. Green hue

of rock 1s dub t o a l t e r a t l o n products. Metnod of ctremlcal anelysls not spec l f l ed .

8 2 ~ t 1 0 6 4 ~ 56'31 '50'' Petersburg PTd Basalt--Plagloclase and c l lnopyroxene porphyrl t lc ul t h well developed t racnyt l c

133O50 '20" C-6 t ex tu re . F l w al lgned andealne mlcrol l t e s occur u l th minor Inters11 t l a l rre3h end

d e v l t r l f l e d g lass , and Intergranular cllnopyroxene. One percent c d l c l r e - r l l l r d and

feuer quar tz - l t l l ed amygdules. Abundant lntergranular opaques. Fa i r ly f resh .

82PB065A ~ 6 ~ 3 2 ' 2 6 " Pctsrsbura PTd Altered Basalt--Plagloclase And cllnopyroxene porphyrl t lc u l t n 4 a u w p h l t l c r o u n d -

1 3 3 ~ 4 1 '37" C-6 mass. Euhedral L O aubhbdrdl zoned and twlnned labradorltm ana smaller l e s s abunndnl

clInopyroxcne phenocrysts. Groundrnass of rndeslne l l t h a , a trongly a l t e r e d cllnapy-

roxenb l a l h a , and I n L r r ~ r a n u l a r opaques. t h l n sec t lon ahous up t o 25 percent

aecondary c h l o r l l e and c a l c t l e .

62SH0098 ~ 6 ~ 2 7 ' 0 8 " POtaPsburg PTd Altered Basalt--Subopnltlc And porphyrltlc. Sparse l abrador l t e plagloclase pheno-

132~56'35" 8-3 c ryn t s up t o 5 mm i n l e n ~ t h occur ,J'ong wlth smaller cd lc lc andeslne l a t h s . Sub-

oph l t l c cllnopyroxene is uul l i . . Iec.. t o green mlca, c a l c l t e , and ch lo r l t e .

Approxlmal el y 4 percant opdque* prcs-I~L. Oulcrop I s 10-meter-thlck flow. >-. -

39

Table 2.--Petrographic deacrlpt lons of aample 1 0 ~ 4 l I t l ~ 3 - - C 0 n t l n ~ b d .

Hap N m ber

Sample Lat l tude nap Nmber Long1 tude Quadrangle Unl t Sample descrlpt lon

Taao Cranl te of Central and Northern Etol ln Ialand--Amphlbolc mlkali g ran l te , granlttl and @ l k r l l quarto oyeni te wlth mlnor - mounts of quartz ayen l te t o syeni le . HilsslVe, nonfollhted, 1aOks mlaro l l t l c Covl t l l s , hcmogeneow a t outcrop sca le .

Petropraphlc fea tu res Include: Ooarae graphlc t ex tu re , d l s t l n c t maflc mineralogy of rodlc amphiboles, dark b row t o

rrddlsh-broun b l o t l t e . and abundant i ron-r lch pyroxene. Acoerawy mlnorala include Iphenl. a l l a n l t e , r a r e f l u o r i t e and

magnetlta.

tgDB139A ~ j 6 ~ 0 7 ~ 4 6 ~ Petersburg t m e B i o t l t e Alkall Cranl te--Healm-palnod, mla ro l l t l c . 8 0 r l a t e wl t h Accessory magnetlte;

132°35'01m A-2 C.I. 03; b l o t l t e a l t e red t o oh lor i t e i p e r t h l t l c and graphlc 1ntergrOUthS. S ta t ion near

contact wl t h hornfelaed grayuacke and a r g l l l i t e .

80DBO5lA 56°10'13" Petersburg Tmae Blotlte-Ampnl bole Alkall Granltr--Medlru-gralned, mlaro l l t l c . l e r l s t e u l th acceaJory

132"23'39" A-2 aphene; C.I. 03; graphlc an5 p e r t h l t l c l n t e r g r w t h s .

79SKOBEA ~ 6 ~ 0 9 ' 0 1 Petersburg Tmae Blotlte-Hornblende Alkall Granlte--Fine- t o medlm-grained, massive, s e r l a t e wlth

1 32'22'35 A-2 accessory opaque minerals; C.I. 03; p e r t h l t l c faldspar . Small basal t dike present.

8 1 8 ~ 2 6 6 ~ 56'01 @5Ow Petersburg Tmae Blotlte-Hornblende Alkali-Quartz Syenlte--Medium-gralned, masalve, equ lqanu la r wlth

132°16132n A-1 mimr cllnopyroxene and acceaaory aphene and magnetlte . P e r t h l t l c feldspar . In aharp

oontact wlth Tmme. Small basal t dlke present.

79DCllllA 56°07715" Peteraburg Tmae Blot l tcPyroxene Quartz Syenlte--Medim- t o coarse-palned, maaslve, a e r i a t e

1 32°34'10" A-2 with aoceaswy o l lv lns . opaque minerals 4nd a l l a n l t e . C.I. 08. Uafic minerals a l t e r e d

t o c h l o r l t e ,

Granlte o r Central and Northern Etol in Island--Massive, nonfol iatea; weathers a l a t l n c t l v e pale orange t o whlte: mlaro-

l l t l c c a v l t l e s common; hunogeneous a t outcrop sca le . Petrograpnic fea tu res ; Rraphlc and mlcrographlc lntergrowthsi

well developed mlcroperthl l e : dark brown t o Ereeni ah brown b l o t i t e and s u b r d l n a t e green t o blue-green hornblende,

uhlch a re of ten p a r t l a l l y a l t e red t o ch lo r l t e ; accessory mlnerels lnclude aphene, a l l a n l t e , and magnetlte; l o c a l l y ,

enldote l l l l s m l a r o l l t l c cav l t i ea .

81 RK268L 56°05'05m Peterabura Tmge Bioti t e Granite--Flne- t o medlm-grained, lnequlgranular wl t h aoceasory opaque mlnerals

1 32°11*00" A - 1 and aphene. C.I. 03; mlnor pe r th l t e . epldote in v u p . Minor alteration La Chlorite.

8iTn063C 56O06'56" Petersburg Tmee B l o t l t e Alkall Granlte--Fine- t o medlm-gralned, m l a r o l l t l c , a e r l a t e wlth accessory

1 3 2 ~ 2 1 ~ 3 1 ~ A-2 aphene and magnetite. C.I . 02. B lo t l t e a l t e red t o cn lo r i t e ,

79SK151A 56°06159" Petersburg Tmge B l o t l t e Granlte--Epidote bearing, f ine - t o aedlm-gralned, equlgranular ~ r a n l t e wlth

r 32°28*2811 1 - 2 minor alteration. C.I. 02; outcrop oontslrcl rounded, t ~ n e - g r a ~ n e d h o r n b l e n d e - b ~ o t ~ t e

Incluslons wlth C.I. 15.

BlRK271A 56°05q03n Petersburg Tmge Blotlte-Amphlbole Aluall Grrnlte--Medium-gralned, equigranular; extreme1 y a l t e red .

132°21'41" 1-2 Aphanltlc r h y o l l t e dike exposed i n outcrop.

a imo62s 56°07*\8n Potsrsburg Tmge nornb:enc~e-~lot i te Alkali ~ranlte--nedlum-gralned. s e r i a t e , C. I . 03. na r ic minerals

i 3z021 '33" A-2 a l t e r e d t o c h l o r i t e . Sample col lected near contact u l t h quartz manzodlorlte.

Nunerous a lka l i g ran i te dlkes and apophyses Into quartz monzodiorltu.

8lTM6hA 56'06~32~ Pateraburg Tmge Cllnopyroxene-Blotlte-*nphlbolc Alkali Grani te--Hedlu-gained, a e r i a t e . C.I. 03.

, 1 3 P 2 2 * 0 2 ~ A-2 Alterat lon of maflc mlnerala t o c h l o r l t e and plagloclase, epidote r i l l s vugs.

81fn065A 56O05'53" Petersburg Tmgr Blo t l t e Alkall CrenltelGrnnlte--Medim-gralned, s e r i a t e . C.1. 05. Blo t l t e ex-

132'21 '33" A-2 t r m e l y a l t e red t o oh lor l t e .

a i snor jc ~ 6 ~ 0 3 ~ 5 0 ~ Petersourg tmpe B i o t i t e Alkall ~ran~te/~ranlte--nedlun-grained, inequigranular, C.I. 03. Bio t l t e

132°181221' A - 1 allrrred Lo ch lor l re . Cut by quartz and K-spar cr:.pnyry rhyo l i t e dlkas.

Table 2.--Petrowaphl c deao r lp t 1 ons of simple loca l 1 tles-Cont 1 nued.

Map Sample La t i t ude Map Nmber Nlnber Long1 tude Quadrangle Unl t Sample Oeocr lpt lon

100 B l W 6 1 B 56°07*27m Petersburg tmge B l o t l t e A lka l i Granlte--Mtrdlun-gralned, a e r i a t e . C . L . 04. Srmple 1 s from a dike In

132'21 q47n A-2 qua r t z monzodlor l ts of unl t Tmme.

101 78RS1218 5 ~ ~ 1 6 ' ~ 6 ~ Pateraburg Tmge B l o t l t e Granlte--Plne- t o ooarae-gralnad, Inaqu lg rmula r , And l o c a l l y po rphyr l t l c ;

1 3 ~ % 0 * 3 9 ~ B-2 m l r r o l l t l o wlth aocesawy hornblende. sphrrne and Opaque mlnarala . C.1. 03. Per-

t h l t l c and graphlc l n t e rg rou ths . K-spar has p l ag loc l a se cores . B l o t l t e a l t e r e d t o

o h l o r l t e .

lo2 B2DB097A 56°16*27" Peteraburg Tmge Hornblende-Blotlte Granite--Fine- t o medlm-gralned, masalvr. mqulgranular u l t h acces-

1 32030826* 8-2 so ry aphene and opaque mlnerals . C.I. 03. P e r t h l t l c with K-apar rlmmine acme plaelo-

c l a s e . Mlnor c h l w l t e a l t e r a t l o n of b l o t l t e and hornblende.

103 82DB263A 5 ~ ~ 0 2 ' 2 5 * Peteraburg Tmge Hornblende-Blotlte Grani te--Ser la te , d m l n a n t l y medium-gralned, ma3aive. C . T . 08 .

1 32°06q00n 4-1 Porphyr l t lC wi tn mlnor inclualona up t o 5 mm. Accessory opaque3 and mlnor a p a t l t a .

Sane c h l o r i t e a l t e r a t i o n f r m hornblende.

104 82SH107A 56O02~56" Pateraburg fmge Amphl bo lo -B io t l t e Cranl te--Flne- t o medi urn-grrl ned, equl g ranu la r , C . I . 02. Zoned

132°11'19n A-1 p l ag ioc l a se .

105 B2RK703A 56°15 '30~ Petersburg Tmge Hwnblende-Biot i te Granl te--Medlm- t o coarse-grained, mla ro l l t l c , inequlgranular

132°32102w 0-2 with accessory sphene and opaques. C . I . 04 . Graphic with K-spar rlmmlng PlaEiO*

c l a s e . Marlo mlnerala a r e Intergrown.

106 82$1(149A S ~ ~ O O @ I O * Pctersburg fmge B i o t i t e G r a n l t e - - ~ i n e - t o medium-gralnea, rpa rae ly pOPphyrlt10 w ~ t h p l a g i o c l a l e

1 3 2 ~ 1 1 150n A-1 phenocryats rluunea by K-spar . C.I. 02.

107 82DB095A 56'1 3' 14" Petersburg Tmge Hornblende-Biotite Granite--Medlm- t o coarse-grained, masslve. ~ c r i a t e wl t h

1 3 2 ~ 2 6 ~ 4 7 " A-2 accessory opaque3 and npnene. C.I. 06. Mlnor p r t h l t e , tu lnned plaglocla3e

rimmed by K-spar. Mlnor c h l o r l t s md carbonate a l t e r a t l o n .

lOB 79StlO59A 5 ~ ~ 0 5 1 3 4 " Petersnurg Tmge Hornblende- l lo t l te Granite--Medlm-gralned, s e r i a t e , C.I. 05. Magnet1 t e 1 s abundant

1 3 2 ~ 2 5 ' 4 9 " A-2 Mario mlnerals a r e f r e s h .

105 7AA114 56°16'55w Peteraburg Tmge M l a r o l i t l c Granite--(Amax sample--Age da t a only . Other deac r lp t ive inlOrOIatlOn

l3z03l 1451t 8-2 mnd gwchomlcal values not lncluded i n t h l s r e p o r t .

Tame Ml@nat l t lc Granl t l o Rocks of Centra l and Northern E t o l l n I s l a n d - - M l p a t l t l c na tu re l o c a l l y r e f l e c t e d by eUt en3lVe dlklng

and abundant incluJlOna. M a ~ s l v e and e x t r m e l y heterogeneous. Pet rographlc f e a t u r e s Include zoned p l a g l ~ c l a a e l o c a l l y

rlmmed by K-apar, o l o t a of l n t e r a t l t l a l K-apar. and r a r e mlcrographic l n t e rg rou ths . Mafic mlnarals a r e commonly

Intergrown; lnclude abundant cllnopyrvxene and s p a r a e orthopyroxene. uhlch ccmmonly occur a s co re s In hornblende.

B l o t l t e , r a r e o l lvbne and secondary Clorouu bmptil w l e . Accessory mlnerals lncluae spncne, apat l t e , mapnr:iLe and

a l l m l t e .

110 8208260A 56O03'1 6" Peteraburg T m e Hornblende-Blot i t e Cranl te--Medlun-gralned. po rphyr l t l o , C . I . 10.

132O07'04" A-1 Accessory a l ~ a n l t e . Gran l t e In oontact w ~ t h a p a t l t s .

111 lltnD59B 56'00~29" Pateraburg T n e ~ l o t i t e - ~ w n b l e n d e Quar t z ~ y e n l t e - - ~ l n e - t o n e d l u - w a l n e d , lnequlgranular . C . I . 06.

i 32°16108n A-1 occu r s as d ikes i n r lno-gralnud monzodlorlte. Fresh rock.

112 79AF020A 56°09'18" Peteraburg T m s Blotlte-llornblende Quar t z Monzonlts--Hedlm-gralne4, a e r l r t e t o vary spa r se ly por-

132"28'08" A-2 p h y r l t l c , C,I. 1 3 . Moderate a l t e r a t l o n of marl@ mlnerals t o chlorite. Cul by basal t

dlktr.

4 1

Table 2.--Petrographic descrlptlona of sample 1ooalItles--Continued.

h p Nun ber

113

Sanpl. Latltude Hap Nunber Longltude Quadrangle Unit Sample deaorlptlon

82KR090). 56004*3qn Patwsburg TuDe Hornblende-Blot1 t e Quartz Monzodlorl te--Flne- t o medlm-gralned. equlgranular . C . I . 25.

Plagloclase has K-spar rlms and ser lo l te alteration; alnor pyroxene. Very mal l

blotl te-rich tonal l te inclusions present. Fresh maflor.

T9SKO83A 56°09'39" Peteraburg Tme Pyroxene-bearlng Blotl te Monzonlte--Very rlne-gralned m d f e l s i e matrix wlth pheno-

132°29'51 ,, A-2 crystn or zoned plagloclase, c l lnopyroxene, blot1 t e , potaaalu feldspar and blur-green mphlbole. Hypldlunorphlc, C.I. approximately 40. Rock I s altered and I s probably

hypabyasal or n border zone.

81SKl69C 56'1 1'02" Peteraburg T u e Blotl ie Syenlte--Medim-gralned, Inaqul@rmular. C. I. 10, nlghly altered, zoned

132°12'41n A - 1 plagloclase. Rock Intrudes a f lner gralned quartz syenite. Accessory opaques.

Plagloclase high1 y s e r i l l zed.

81 TMO61A 56°01'21n Petersburg Tmne Hornblende-Biotite Quartz Honzodlorlte--Flne- t o medlm-gralned, porphyrltlc. C.I.

132'21 '47" A-2 22. ~ l o t i t s phsnocrysts, K-spar clots and ml nor cllnopyroxene. Some maflc mineral

al teratlon t o chlorlte, Cut by dlka of alkall granlte.

62RK836B ~ 6 ~ 0 2 ' 0 4 " Petersburg Tme Blotitelici-nblende Quartz Mnzodiorite--Fine-gralnea, microporphyry. C.I. 20.

1 32°12'38' A-1 Chlwlto and epldote f l l l vugs.

82KR089A 56O03'25" Peteraburg Tmme Pyroxene-Biotite Granodlorlte--Flne-grrlned, aqcigranular. C . I . 17. Mlnor hornblende,

1 3 ~ ~ 1 ~ * 9 0 ~ A - 1 zoned plagloclaae, irregular K-spar *clotsn. Thln random fe l s l c segregation layera.

Sme alteratlon to chlorlte.

82DB25qA 56'01 '51 " Pctsrsburg Tme Blot1 t e Cranlte--1nequlgranular C.I. 08. Disamlnated rolybdenl te , accessory aphene.

1 32'04 I 01 rn A- 1 mnd r l lanl te . Chlorlte alteration. Cranlte la leucoaane of mlgmatlte u ~ t h a quartz

monzoni t e nelaame.

79RS131A 56O05'48'~ Petersburg Tme Hornblende-Pyroxene-Blotlte Quartz Dlorlte--Medium-gralned, equlgranular. C.I. 19 .

132~28' 10' A-2 Quartz monzonlte dlkus preaent . 82SK157A 56°01n49n Peteraburg Trme Pyroxene-~ornblende-~lotlte Quartz Monrodlorl te--~edlum-~ralnsd, equigranular , C. I. 30.

132°10118w A-1 Local ag~la t l te with monzodlorlte, also irregular quartz velna.

79~SO68A ~ 6 ~ 0 4 ~ 1 8 ~ Petersburg Tme Pyroxene-Hornblende-l3lotite Dlorlte--nedlw-gralned. equlgranulw. C . I . 37. Zoned

132'25'1 5" A-2 plagloclase; hornblende ulth Ellnopyroxene cores. Secondary b lo t i te , hctlnoll te. and

chlorlte.

62DB262C 5b003'lln Peteraburg Tme Blotlte Quartz Diorlte--Equigrmu)rr, C.1. 30. Quartz d ior i te l a oldest unlt In r p a -

13P05*4lqt A-1 t l t e zone, cut by Irregular porpnyrltic granite dl kes and crosscutting granite apl i te

dl kes .

82SK154A 56°02'1 3" Petersburg T a e Pyroxene-Blotlte-Hwnblends Cabbro--Medlm-gralned. aubophl t l c , inequlgranular . C.I.

1 32°12128w A-1 35. Zoned plagloclase a l t s r lng t o s e r l c l t e , mafic mlnerals al tering t o chlorlts .

82KRO86A 5 ~ ~ 0 4 ' 0 0 ~ Peteraburg Tme Cabbro--Fine- t o medl um-gral nedi subophltic in texture. C .I. 35, Uagnesl an 01 lvlne

132001 '94" 4-1 wlth Iddlngslte, red-wwn biot i te , pale mphlbole, and opapues M reactlon rimy.

LabradorlLcr plagloclase I s partly encloned by cllnopyroxane. Mlnor cnlorit lzatlon.

Alkali Cranlte of Northwastern Etolln and Southeantern Zaranbo Islands--Homogeneous, n4Sllvbl nonfollated, medlum- to

coarae-gralned, wlth mlaroll t lc cavlt les ana local hornfels Incluslons. Petrograpnlo reaturea Include psrthlt l c alkal l

feldspar, graphlc and ~LCrOgrlphlC textures, Matlo minerals are altered to chlorlte; they include green, blue-green

end blue mphl bole, dark brown Lo reddl sh-broun blotl te. local green pyroxene; accessory olnerals Include magnet l t a .

nphena, a l l rn l t a , and apati te; locally cpldota f I l l s mlarolltlc CaVltleS. Inaludes mlnor subophl t l c hornblende-blotlte

pyroxene d lor l te almllar t o those or unlt Tame.

Table 2.--Petrographic deso r lp t ions of a m p l e looal l t lea--Cont inued.

Slap1 e Lat I t ude nap Umber Long1 Lude Ouaarangle Unlt

-- - .

788COl6A 5C016'43" Peteraburg Tmaz B l o t l t e Granite--Medlm-gralned, equlgranular . C.1, 04. B l o t l t b extremely a l t e r e d t o

1 32O39'25" 8-2 c n l o r l t e . Chmlea l ana lys l a Dy r r p l d rock method.

~ Z S K O O U A 56°17'50" Peteraburg tmaz ~ o r n b l e n a e - ~ l o t ~ t e ~ r a n i t e - - ~ e a ~ m - p a l n e d . e q u i g r m u l a r , C.I. 02. Abundant maric

1 32°39'00* 0-2 r l t e r a t l o n t o c h l o r i t e .

79081 21 A 56°20v53m Peteraburg Tmaz Amphl bo le -B lo t l t e Granlte--Fine- t o medlrm-gralned, C.I. 03. Annedral t o

1 32°48*~9m 8-3 mubhedral p l r g l o c l a s e I s weakly zoned. Cut by rhyodaol te and basa l t a lkes .

79DGO98A 56°20'53" Peteraburg Tmaz Amphl bole-Blot1 tr Alkal i Granite--Meaim-grained, inequl g ranu la r , C . I . 03. Cut by

1 3 P 4 8 1 0 9 ~ 8-3 a l t e r e d basa l t d lka .

82RK70Ob 56'1 2'16- Petersburg Taaz Biotitc-Hornblende Alkal i Granlte--Medl m-g ra ined , lnequlgranular , C . I . 04. Small

132°34*32w 1-2 ho rn fe l a l nc lus lons . Marlo minerals t r l r l y f r e sh .

79SK130A 56°19'26" Peteraburg Tmbz Biotite-Hornblende Alkali Granlte--Flne- t o medlrm-pralned. g l aoe roporphyr l t l c , C.I..

132°46q16m 0-3 04. Mlnor maflc a l t e r a t l o n t o o h l o r l t e . Fine-grained I ~ C ~ U S ~ O M of ln termedlate

oonporl t ion.

Heterogeneous C r a n i t l c Rocks of Centra l Kuweanof ana Northeastern Kuiu Islands--Poorly expoaed, nonfo l l a t ed , Inequl-

granular 16 pOPphyrltiC, f l n e - t o medlum-gralned. M l a r o l l t l o wlth mlo rope r th l t l c K-spar and mleregrapnio

In t e rg rov ths . Ha l l c mlne ra l s m n s l a t o r brown b l o t l t e , green-Wown t o blue-green hornblende and r a r e pyroxene;

accessory mlnerala Include rphene, mbgnetlte and a l l r n l t e i e p l d o t e f l l l s m l a r o l l t l ~ cavl t i e s . Inc ludes mlnor pyroxene-

r l c h qua r t z monzod lwi t e and pyroxene-blot l te d l a l t e a l m l l a ~ t o rocks rosoc ia t ed u l t n un l t Tmgk.

BUDD-009 56°47*11m Petersburg Tmqk Rlebeok l t e - a lb l t s miorogranite--forms r sill o r l a c c o l l t h I n Eooene sandstone and

1 33°44'01n D-6 c o n g l m e r a t e . Flne-gralned aggregate w m i s t a of r l e b e o k l t e , qua r t z and f e ldspa r .

Feldspar ohowr no d l a t l n c t twlnnlng and Is clouded by a l i g h t weather lng.

Rlebeckl te makes up about 15 percent or t h e rock. Method of chemlcal ana lys l a not

spec l f led .

62KHOlVA 56°~61b7" Petersburg Tmqk Alkal i Granite--Flne-grained; subequlgranular . C.I. 6. Poorly developed grano-

1 33°43106w 0-6 phyr lc t e x t u r e . Angular l n t e r g o u t h a of a l k a l i f e l d s p a r wi thin equant m h e d r a l

qua r t z g ra ins . Minor p l ag ioc l r se ; s e g l r l n e ; accessory opaques p re sen t , Maaslve

and hmogeneous I n outcrop.

8?KR017A ~ 6 ~ 4 8 ' 0 1 " Petersburg Tmqk Aeglrlne M l c r o g r a n l t r - f i n e - t o very f lne-pralned. C.I. 10. Hypldlanorphlc granular .

133O47'59" D-6 Anhedral qua r t z -only intergrown wlth # l k a l l f e ld spa r . Subhedral p l ag loc l a se .

Aeglrlne and r a r e r l k a l l f e ld spa r pnenocrysts p re sen l . Minor i r o n s t a l n l n g .

82bR015A 56°4711 3" Petersburg Tmqk Aeglr lne Mlc ropan l t e - - f in s - t o very f ine-gralned. C . I . b. Hypldlanorphlc subequl-

i 33°43'48tt 0-6 granular with g r rpn lo qua r t z , a l k a l i f e ld spa r i n l e rg rou tha . Common a e g l r l n e and

spa r se aeglrlne-rlmmad green-blue mph lbo le present . Q u a r t z - l l l l e d m l a r o l l t l c

cavl t lwa ccrmnon.

82KROI6A ~ 6 ~ 4 7 ' 3 6 " Petersburp Tmqk Aeglr lne Mlcrogranlte--Flne- t o very f ine-gralned; hypidlaaorphic Inequlgranular .

133°43107" D-6 C . 1 . 6 . General ly subhedral a l k a l i t e ldapa r l a t M up t o 1 ul i n l eng th l n t e r g r w n

wlth o l c rog raph lc q u a r t z l a l k a l l f e ld spa r g r a l m . p l a # l o c l u e , and a e g i r l n e pyroxene.

Accessory a l l a n l t s and s p a r s e green-blue amphlWl0 p m s e n t . Ulnor i r o n s t a l n l n g .

79RSlSSA 56°37m56w Pblersbura Tmqk Blot l te-Hwnblende Quar t z Mnzonl to--Fine- t o med lu -g ra ined , lnequlgranular , C . I . 08.

133O24'49" C-5 Plag loc l a se l a thu a r e r l m e a by K-spar . Moderate c n l o r l t e a l t e r a t i o n . l nc lus lons Of

more maflc qua r t z monzonlre LO qua r t z d l o r l t e presenl .

82SH052~ 56'36'06~ Por t Taqk Blot I te-Hornblmae Quar t z Syenlte--Medlrm-grained, lnequlgranular , C . I . 07.

13q001 '50" Alexander Twlnnrd P l a g l 0 ~ l a 9 e l a t h s rimed by K-spar. Abundant mafic mlneral a l t e r a l l o n t o

C- 1 c n l o r l t e . Inhomogeneo~ outcrop wi th v a r l a b l e t e x t u r e s and c o m p s l t l o n s ,

4 3

nap h p l e Lhtitude nap NmOer Nmber Long1 tude Puadrmgle Unit S m p l e deacrl ptlon

139 TBDB223A 5 ~ ~ 3 5 ~ 1 7 " Potersburg Tmqk Hornblende Qusr tz Honzonlte--Flne- t o medltbn-gralned, pOrphyPltlC, C.I. 15.

1 33°59'~0n C-6 P l ~ g l o c l a s e phenocryats wlth a e r l c l t e a l t e r a t l o n and K-spar rlms. Abundant ch lo r l t e

a l t e r a t l o n . Apl l l s dlkes present.

140 LIODBO69A 56°35146n Port tmqk Blotlte-Hwnblende Quartz Monzodlwlte--Fine-grained. p a p h y r i t i c , C.I. 08. Twinned

1 34°00'21 Alexander and zoned plagioclase phenncrysts u l t n n e r i c l t s r l t t r a t i o n . Abundant c h l o r i t e a l t e r -

C- 1 r t lon . Very f i n e gralned quartz d l o r l t e lncluslorrp.

1111 B3SKllt6A 5 6 ' 3 6 ' ~ 5 ~ Peteraburg Tmqk Quartz Monzonlte--Flne-gralnedi Insqulgranular with crowded plagloclase phenocrysts

133°22'31n C-5 m d 20 percent l n t e r r t l t l a l quartz , 10 percent ore, 5 percent chlorite. C.1. 25.

Strong1 y a1 tered.

142 B2SHO6OA 56°32100" Peteraburp Tmqk Chlor i t e Quartz Honzonite--Uedlum-grained, lnequlgranular, C . I . 12, Tulnncd plaglo-

1 3 3 ~ 4 5 ' 5 7 ~ C-6 a laae with a e r l o l t e a l t s r a t l o n . M a f i a mlnerals completely a l t e r e d t c ch lor l l e .

143 83DBZ02A 56O37'55" Petersburg Tmqk Quartz Honzndlorlto--Qlne- t o medlum-gralnedi s e r l a t e textured. C.I. 20. Ollaoclase

133O36'37" C-5 t o andeslne plagloclase commonly r l m e d by myrmykltlc intergroutha. Subophltlc clino-

pyroxene; hornblende replaced by c h l o r l t e ; 5 percent opaques; acce3sory a p a t l t e . 7

percent secondary c h l o r l t e , epldote, and a c t l n o l l t e .

144 79DG039A 56°36'211n Peteraburg Tmqk Pyroxene-Amphibole Dlorlte--Fine-pralned. sparsely porphyrl t lc , C.I. UO. ScaLLered;

1 33O45'42" C-6 zoned plagloclase pnenocryrts. Moderate c h l o r l t e alteration.

145 79DB038A 56°36*09n Potersburg Tmqk Amphibole ~lorlte--~edium-gra~nea, a t r i a t e , C.I. 08. Zoned plagioclass laLhs. Pyrox-

1 3 3 ~ 4 5 ' 4 1 ~ C-6 ene occurs as cores In hnrnblendb. Abundant Chlorl te r l t e r a t l o n .

146 80DBO438 56O32'24~ Petersburg Tmqk Quartz Latlte--Aphanltle, hunogsneous, somewhat pOrphyrltlc. Phenocrysts a re plaglo-

133O10'39" C-4 c l a s s rlmmed by pyroxene. OrounmaaA m n s l s t s of 10 percent potasslum feldspar . quartz

plagloclase, Accesswy pyr l t e , a p a t l t e , and epldote. Normative ol lvlne. Posslblt.

dlke.

Granlte of Nmthwestern Kuiu Island--Mas$ive, homogeneous, equlgranular t o s e r l a t e , loca l ly porphyrl t lc ; f ine- t o

medlm gralned. n l a r o l l t l c cavl t l e s end flne-gralned mafic i n c l u ~ l o n s . Petrographic fea tu res Include mlcroperthl t lc

K-spar and local a l t e r a t l o n of plagloclase. Haflc mlnerals Include dark brown t o red-brown b l o t l t e and brownlsh-green

t o blue-ween hornblende. Accessory mlnerala ae aphene. magnetite and al lanlLe. n a f l c minerals a l t e r t o ch lo r l t e .

147 82SH054B 56°44'39n Port fmgk Hornblende-Biotlte Cranlte--Fine- t o medlun-gralned, equigranular , C.1, 05. Cranl te

134°20118" Alexander has cn l l l ed margln agalnat a gabbro f l e l d contact .

C-2

148 BODBlllA 56O42'25" Port Tmgk Blot1 te-Hwnblende Cranl t e--Medlwn-gralned, equl granular . C . I . 06. Flne-gralned

134°18v1fu Alexander d l o r l t o i n c ~ u s l o r u .

C- 1

149 bORS051A 56°42'~1" Port Tmgk Hornblende-Blotlte Granlte--Flne- t o mealum-gralned. lnequlgranular. C.1. 06. Minor

134°18'52n Alexander c h l o r l t e alteration.

C- 1

Tmdk Hstcrogeneaur D l o r l t l c Rocks of Northern Kulu Island--Masalve, merlate. medlm- t o oo~rme-gralned extensively dlked and - loca l ly mlgnat l t lc . Petrograpnlc fea tu res Include zoned plagloclase, K-spar e l o t r , intorgrown subopnll lc marlc mlnerals

, OOn8lSting of ollnopyroxene, green-brown hrrrnlrlende, mlnor b l o l l t e , local ortnopyroxene and o l lv lne ; accessory mlner3lS

lnclude aphane, a p a t l t e , r agne t l tu , and a l l a n l l e .

150 80DB049A 56°42'16w Pwt Tmdk B i o t l t s Cranlte--Fine- t o medlun-gralned, porphyrl t lc . C.1, 08. Plagloclarre ptieno-

1 34°16'17" Alexander c rys t s a l lured t o s e r i c l t e . Mlaro l l t i c c a v l t l s s local ly f l l l a d ul th carbonate.

c- 1 Abundant a l t e r a t l o n of b l o t l t e t o ch lo r i t e . Crdnlle I s In st1.4rp contact ul lh d l n r l l a .

Table 2.--Pet rographl c dasc r lp t l o w of a ~ l p l o l a c a l l tlea--Continued.

.--

Sample Latltude nap Nunher Long1 t uds: QuadranRle Unlt S m p l e Ceacrlption

82SH053A 56'41 108" Port Tmdk Blot l~o-t lwnblende Quartz Monzodlorite--Fine- t o medlm-gralned, porphyrl t lc , C.I. 12.

134°18t2:' Alexander Plngloclase phenoarysts a r e rlmmed by K-apar. Mlnw pyroxene cores In hornblende.

82S~Olr9A 5 ~ ~ 4 3 ~ 3 0 ~ ~ port ~mdw ~iot~te-pyroxene-~ornblende ~ i m i t e - - ~ e d i m - w a l n e d , merlate, C.I. 35. Intergrown

134'21 17- Alexander maflc mlnerals u l t h abundant alteration t o chlorite.

C-2

Gabbros of K U I U Is land and Kewu Islets--Medim-grelnea, dark gray f m J h ana weathered, o l l v l n e and ollnpyroxane-bearlng.

loca l ly deu t r r l ca l ly a l t e red . Forms gently dlpplng s l l l a up t o 500 m thlck.

BOSK54lA 56'48'23" Petersburg Tmgb ~lcrogabbro--Very flne-gralneai r r r l a t e texture. C.I. 30. Abundant lntergranular

133~42'53" D-6 cllnopyroxene and sparse hypersthene ooour u glmerocrysta and m a t t e r e d gralns along

wlth l n t e r s t l t l a l quartz , green-brown mica. accessory opaque* and sphene.

82~ROl8A 56°48'20" Petersburg Tmgb ~lcrod~orite--Holocrystalline; fine-grained. C.1. 35. P w p h y r l t l c with intergranular

133 '4~~52 ' D-6 grounmasa. S l igh t ly a l t e r e d , Zoned plagloclase phenocrysta r l t n graundrnass of pla-

c lase l a t h s , granular ollnopyrorene, l n t e r ~ t l t l a l quartz and ac lcu la r mphlbole.

Accessory magnet1 t e ; secondary ca lc l t e and(?) devi t r l f l e d glass . Maaslve outcrop.

80SK532A 56°48159n Peteraburg fmgb Quartz ~onzod~or~ts--~lne-grelned. C.1. 30. Intergranular t ex tu re with cllnopy-

1 33°45'48" D-6 roxene, hornblende. magnetite, and l e s s common a l t e red g l a ~ a patches. In te r -

s t l t i a l mlcrographlc and wanopnyrlc potassium feldspar and quartz. Trace of

a p a t l t e . nlnor secondary green mica and ch lor i t e .

80D9190A 56°51859" Peteraburg Tmgb ~ ~ c r o d i o r ~ t e - - ~ ~ n e - g r a ~ n e d . C.I. 40. S u b o p h ~ t ~ c diebase texture. n a t i c s a re

133"3lv11" 0-5 cllnopyroxena, hornblende, and opaquea ( p y r l t e noted In the field). Interstices

and mygdulea a r e f l l l e d wlth aecondary oe ladont te (? ) , aphene, and c a l c l t e .

Intruslvb rocks of the Chllkat-Prlnce of Wales plutonlc provlnce expaaed on Prlnce of Wales, Koacluako and Kuiu I3land.

Hornblende quartz monzodlorlte wlth minor t o n a l l t e , granodlorl te , quartz d l o r l t e , d l o r l t e , quartz monzonlte and

monzodlorlte. Masslve t o r o l l a t s d , equlgranular t o loca l ly p ~ r p h y r l t l c . medlum grained, loca l ly hornblende porphy-

r l t l c local mafic l n c l u ~ l o n s . Petrographic feature* a r e s e r l a t e plagloclase, l n t e r s t i t i a l K-*par, occasional pol-

k l l l t t c U-spar c l o t s . local pyroxene.

8 0 ~ ~ 4 4 3 ~ 56°05q00" Port Alexander Kwqo Blot1 t e Cranodlorlte--Medim-walned, hypldlmorphic-granular , inequlgranul ar , C . I . 07.

134"12'20w 1-1 l n t e r s t l t l a l material is very f lne -gra~ned quartz and potassium feldspar . tllnnr

amount of acce~sc+-y opaques, sphene and epldote. Plagloclaae 18 hlgtll y s e r l cl t l zed.

7 9 ~ ~ 1 0 8 ~ 56'12'36~ Peteraburg ~ u q o Hornblende Quartz ~ o n z o d ~ o r i t e - - ~ o t a s s ~ m feldspar porphyri t ic , a e r l a t e but dominantly

133'26'38" A - 5 medlua-gralned. C.I. 02. Accessory mlncrals include opaques and sphene. Plagloclase

1s a l t e r e d , hornblende I s chl0rl t iZed.

79SK022A 56°10'30" Petersburg Kuqo Hornblende Cranodlorlte--Medlm-gralned, hypldlunorphlc-granular, C.I. 05. Mlnor

133°22*51n A-5 opaque3 and euhedral sphene a re acoeJoory minerals, Minor plagloclase and horn-

blende a l t e r a t i o n . VlslDle pyr i t e , chalcopyrl te . Dornlte and c l o t 3 of molybdenl t e t o

1 as a t outcrop sca le .

79RS018A 5 ~ ~ 0 9 ' 4 8 " Peterabur8 Kuqo Hornblende Tonal lte--Fol l a ted , porphyrl t lc quartz , medlm-g.ained, C.I. 05. Mlnor

133°24v15" A-5 sphene and opaques. B l o t l t e t o t a l l y ch lo r l t l zed , hornblende r l l g h t l y a l t e red .

Vlslble pyr l l e a t outcrop acale .

78DB204A 5 ~ ~ 1 6 ~ 0 1 Port Kuqo Biotlte-Hornblende Granodlorlte--Medium-grained, hypldlmorphlc-granular, C.I. 08.

1 34°10t43n Alexander Euhedral sphena and opaques a r e accessory mlnerals. Plaglnclase l a hlghly

11- 1 s e r l c l t l z e d . hornblende i s domlnently engulfud by c h l o r l t l z a t l o n , and biotite I s only

l l l g h t l y a l l e rad .

t a b l e 2,--Petrographic descrlpt lons nf sample 1oaalitle~--Continued.

... --

Map Sample Lat i tude nap Nmber Umber Lone1 tude Quadrangle Unlt Sample descrlpt lnn

162 19SKO72A 56°13*20m Peteraburg Kwqo Hornblende Quartz Honzodlorltc--Pledlrm-gralnad, hypldlunnrphie, epulgranular. C.I. 06.

133°25'35w A-5 Subhedral rphene m d opaque3 a r e accessory mlnerala. Plaglocl lue I s SerlCit lzad;

hornblende I s largely unal tered.

163 QRS015A fr6°06'13n Port Alexander Kwqo Blotlte-Hornblende Cranodlorltc--Flne- t o medlum-qalned. Hypldlcmwphlc granular,

1 3 4 ~ 1 1 ' 1 8 ~ ~ A-i C . I . 12. Andeslne t o 011goclsse plagioclase 1 s o s c l l l r t w y zoned and s l l ah t ly s w l -

c l t l zed . Thlr ty percent enhedral quartz along u l t h anhedral t o subhedral l n t e r z t l t i a l

a l u a l l fe ldspar present . Hwnblende and b l o t l t e contaln minor c h l o r l t e . Accessory

aphene end megnetlto.

164 80RSO19A 56°01*01m Peteraburg Kupo Hornblende Puartz Monzonlte--Potasslum feldapar porphyrl t lo , medlrm-gralned, hypidlo-

1 33°23*50m A-5 mwphlc. c.1. 07. Accessay magnetltr. Hornblende s l l g h l l y a l t e r e d , plagloclase I s

r l t e r e d . Very mlnor nyrmeklte Intergrouths.

165 80DBO77A 56O05'~7* Port Alexander Kwqo Blotlte-Hornblende Quartz Honzoalorlte--Medlum-gralned, Inequlgranular, serloporphy-

i3r0io*33w A-1 r i t i o . C.I. 1 1 . Dlasemlnated magnetite and aphrne up t o 2 mm. Hlnor c h l o r i t e

a l t e r e t l o n i n hornblende and b l o t l t e . Occaslonal myrneklte Intergrouths.

166 82SH056B 56°07'49" Port Alexander Kwqo Blotlte-Hornblende Cranodiorlte--Foliated, equigranular , coarse-grained, C.I.

1 34°10'00' 1-1 15. S e r l a t e , u e l l wned plagioclase u l th mlnor s l t e r a t l o n of the cares. Accessory

mineral8 lnclude opaques, a p a t i t e and dlmond-anaped eunedral sphene.

161 79DB097A 56°05159n Petersburg Kuqo Blotlte-Hornblende Quartz Monzodlorltc--Slightly f o l i a t e d . medlunrgralned. C.1. 09.

133°29'20" A-5 We11 zoned, r e r i a t e plagioclase, wlth minor s e r i c l t r a l t e r a t Ion. Accessory mlnerals

lnolude aphene and opaques. B l o t l t e 13 camonly a l t e red t o ChlOrlte.

168 82SH051A 56"08~25" P o r t Alexander Kwqo Hwnblende Quartz Diwl te--Maaal ve, plagloclase porphyrl t l c . f lne- t o medl m-

1 3 ~ ~ 0 9 ' 5 8 " 4-1 gralned. C . 1 , 20. S e r l a l e , uol l zoned plagloclaJe u l th c m o n s e r l c l t e , Accessory

opaques. aphene, and a p a t l t e . Rounded, flne-gralned maflc lncluslon present.

169 7906031C 56°09'03" Peteraburg Kwqo Quartz lonzodlorlte--Flnr gralned, equigranular. C . 1 . 13. No b l o t l t e . abundant

133'26153" A-5 pyroxene. mlnor hornblende. Accessory a p a t l t e and sphene. Sample 1s a 10-m-t hlck

9111.

170 &SHOSSA 56°08'07'1 Port Alexander Kwqo Blotlte-Hornblende Cranodlorlte--Medlrra-gralned, equlgranular , masslve. C . I . 17.

134°09'05" A-1 Aocessory mineral9 Include opaquea. r p a t l t c and sphene. Ser la te . well zoned plaglo-

c l a s e wlth mlnor e e r l c i t e a l t e r a t l o n , Pllnor myrmeklle Intergrouths.

171 7QRS017A 56°05140n Pateraburg Kvqo Hornblende Quartz Plonzodlorlte--Foliated. I n e q u l g r a n u l ~ , hypldlmorphlc. C . I . 15.

133'21 ' 3 U " A h 5 Scat tered magnetlte and sphene. No b l o t l t e . Hornblende par t ly a1 tered t o chlorl t e .

Some myrmeulte Intergrouths. Ylslble pyr l t e a t outcrop.

172 79DB033A 56°07123n Petersburg Kuqo Hornblende Quartz Mnnzodlorlte--Hedlm-gralned, equl granular , C . I . 13. MlnOr

133'25'43~ A-5 pyroxene and b i o t i t e . Accersory a p a t l t e , aphene and opaquas. Chlorl te alteration In

hornblende.

173 19DB032A 56'08'42* Petersburg Kwqo Hornblende Quartz Dlorl te--Serlate , lnequlgranular . hypldimorphic. C .I. 36. Hlnor

i 33°26121n A-5 roceasory sphene and opaques. Abundant subnedral plaflloclase u l th common myrmeklte

Intergrouths.

174 79RS02lA 56°11'08w Petarsburg K w c p Hornblende-Biotite Quartz Dlorite--Foliated, coarse-grained, e q u l ~ r a n u l a r , C.1 . 32.

133°25'55* A-5 Accessory mlnerals a r e magnetite, seen largely a s Inclusions. and mlnor amounts of

sphene and cllnopyroxene. B lo t l t e c l o t s of f resh unaltered f l akes t o 1.5 cm.

Hornblende a l t e red t o c h l o r l l e , plagloclase shrrrs mlnor a l t e r a t l o n I o serlClLe.

Table 2.--=rphlc deacrlpt lons of a m p l e localltles--Continued.

Sample Latltucle Map Nunber Long1 tuds Quadrangle Unl t Sample deacrlpt lon

79SH03SA 56°00q35w Paterrburg Kwpo Blotlte-Pyroxene Dlml te--Madl un-gralned, equlgranular . hypldlmorphlc, C . 1. 39.

1 32°99*51w A-3 Minor hornblende and acceaswy magnetite and pyri te . Al ta r r t lon of pyroxene t o

green amphibole. PlagloolaJe l a t h s a r e a l t e red t o a e r l c l t o .

MDBOWA 56°14100" Peteraburg Kucp Biotite-Hwnblmde Quartz ~onzodlorlte--nedlm-grrlned, Lnept I lg ranu l~ , C.I. 21.

133°26*09n A-5 Unaltered b l o t i t e , ch ln r l t l zed Mrnblende, and pyroxene e r a accessory mlnerala.

nlnor mount of myrmttwlte.

f9DB091A 56°0~*04" Petersburg Kuq~ Hwnblende Monzodlort te--Foliated. s e r l a t e , aomlnantly medlun-gralnsd. hypldlo-.

1 33°24*40* A-5 mwphlc. C.1. 26. nlnor pyroxene, aphene, and opaqurs, Mlnor ch lo r i t l za t lbn

of nornblende: plagloclase a l t e red .

8OSKIIU7A 56°06'31n Petersburg Kwqo Hornblende-Pyroxene Cabbro--Slight to1 t a t l o n of maflca, a m a t l t l c , peematltlc,

133'21 '59" A-5 medium- t o w a r s e - g r a l n e ~ . c . I . 44. Accessory pyr l t e , mafnet l te and $phone.

Mlnw mount of b l o t l t e . Pyroxene ahouz acme alteration t o ch lo r l t e .

K a m - Stephens Pasaage Group Rook. exposed near P t . Hml l ton on Kupreanof Is land and north of Kadake Bay on Kulu laland.

Caloareous l i t h i c Wacke and w e n l t e , t h i n Wdded, f ine- t o very tine-gralned wlth mudstone l n t e r k d a . Orlginal texturea

and structures general1 y preserved.

82SK04bA 56'49'110~ Port Alexander Kbm Altwed Basal t (?)--Cmon plagloclase and sparse r e l i c t pyroxene phenocrysts In a hya-

1 3U000'02" D- 1 l o p i l l t l c groundmass. Plagloclase mlcrol l tes a r e surrounded by a l t e red pyroxene(?),

d e v l t r l f l e d g laas , c h l o r l t e , sphene and c a l c l t e . Contalns pyr l t e . Outcrop descrlbsd

a s agglunerate; volcanlc breccla.

R h h Hound Is land Voloanlcs--Basaltic pillow breccla and plllow lava f l w s , andes l t l c volcanlc breccla. aquagene t u f f , t u f f - breccia and mlnor thln-bedded limestone. Baaal t lc flows a r e messlve and are polygonally jolnted u l th v r s lcu la r tops.

Unit thickness ranEea f r m a rew 100's of m t o more than 650 a.

82SK051A 56'52'18" Port Alexander R h h Altered Volcanlc--Porphyrltlc. Abundant andealne pnehncrysts up t o 2.5 mm In lerieth

134°00'~8" D-1 I n s grounhass oontalnlng p l a g l w l a s e l a t h s , granular t o subophlt lc cllnopyroxene and

up t o 1 3 percent secondary c n l o r l t e , c a l c l t e , p m p e l l y l t e ( l ) , and clay mlnerals.

Forma masslve flows In the f i e l d .

78~B&127A 56O52'53' Petersburg ' lihh Ne t h i n aect lon. Field notea ind ica te "pl l lou basal t?" .

133O56'02" 0-6

63S192a-2 56°52'28" Petersburg I hh Baaal t l c Volcanlc Glass--Green; undevltr l r led. Sample frrm central port lons nf glas!,

133O55' 32" D-6 f ra f l en t s In an aquaerne t u f f . Glass f r a e e n t s are angular* sand alzed; velned and

rlraed by w r t l a l l y devl t r l f l e d brown #la$$ (sample 184, t h i s rspnrt ). S m p l e con-

t a l n s 1 percent c a l c l t e cement. Informatlon from Brru and nurr l er ( 1 966) and Yuffler

and o thers (1969). Chmlcal anal ysl J by grrvlmetr lc method.

80SK599A 57%5*07" 31 tka X h h Altered Ba3alt--Amygdaloldal. Contalns a t l eas t 25 percent secondary mlnerals.

134°00'29n A-1 Dmlnantly sutmpnl t l c ul t h sane lntergranular c l lnopyroxrne and Int ersrl-1 al

d e v l t r l f l e d g l a a ~ . Secondary mlnerdls lnclude c h l o r l t r , punpel lyt t r , z r o l l l e , and

crypt .ocrystal l lne materlal . Sample f r m plllow-flou outcrop.

6351 92.3-1 56°52r28w Peteraburg K hh Basal t ~ c ~ o ~ c a n i c laa as--8rown; pert I a l l y devl t r i f l e d ria. of p e e n g l a s s f rament 3

133'55'32" D-6 (sample 182, t h l s r epor t ) and brown g lass fravnents In an aquagenr t u f f . Sample 13 95

percbnt brown g lass ; 40 percenl of whlch contalns c r y a t a l l l t r a a110 dev l t r l f l ed p l a 3 3 .

Rmalnlng 5 percent of a m p l e contains calcl t r , plagloclast. , and c r y s l a l l l t s s from the

glaaslcmbnt boundaries. Informatlon frmn Brau and Muff1 er (1 966) and Murfler and

otnerv (1969). Cnemlcal ana lys l s by gravlmelr lc method.

Table 2.--Patragraphla descriptions of sample l o c a l I tles--Cant lnued.

nap Sample L a t l t u a e Map Nuinbur Nuptwr Long1 tude Quadrangle Unl t S m p l e dasa r l pt 1 on

1 8 78AHg129A 56°53'07n Per a r sbu rg 7r hh No t h l n s e c t l o n . Sample frCnn "masalvb b a s a l t flow".

186 78AB8126A 56O52'57* Peteraburg l r h h No t h l n aec t lon . 11016 notea l n d l o a t e * u l a e ~ l t e ( ? ) b reoo l rn .

133056*49" D-6

1117 18ABg128B 5 ~ ~ 5 3 ~ 0 6 n Peteraburg w h t ~ N O t h l n aec l ion . F i e ld note* i n a i c a t e *pi l low baJalt ' lH.

1 33°56'50* D-6

82SK038A 56°51155* P o t n n b u r g R h h Altered Basal t (?)- -Strongly a l t e r e d ; anygdaloldal . Hya l loph l t l c wi th l n t e r s t l t l a l

133°55'25* D-6 green d e v l t r l f l e d g l a s s and abundant c a l c l t e - f l l l e d mygdules . Contalna c a l c l t e

pseudomnrphs d (71 pyroxene and a c l c u l a r p l ag loc l a se r o s e t t e s . Sample I r a 1

meter t h i c k p l l l o u f lcu .

x k - Keku volcanlcs expoaed on t h e Cornua l l l a Penlnaula and adJacent Koku I s l e t s . Al tered f e l a l c f lows and flow breccia :

flow-banded. rphana t l c , feldspar-m~croporphyrltic. Minor mafia f l o u s and flow b recc l a , volcanic wacke, volcanic 38

conglomerate, aandstone, p o l p l c t l c pebble conglomerate. green aquagene t u f f , and thlak-bedded o o l l t l c l imestone.

18ABg\3OA ~ 6 ~ 5 3 ' 4 6 " P o r t Alexander ?Ah No t h l n s e c t l o n . F i e l d no te s l n d l c o t e m r h y o l l t e n .

134°05'1 9' D-1

78ABgl3lA ~ 6 ~ 5 3 ' 5 6 " P w t Alexander l r k No t h l n aec t lon . P l e l d no te s l n a i c r t s "rhyolite t u f f " .

1 3 4 ° 0 6 ' ~ ~ 0-1

Ktef - I n t r w l v e rocks of Admlralty-Revlllaglgedo p lu ton lo b e l t exposea on E t o l l n , Yrange l l , Dry, Farm, m d Se rg le f Is lands--

Hornblende-Dlotite t o n a l l t e , g ranod lo r l t e , qua r t z monzodlorlte and qua r t z d l o r l t e . Fo l i a t ed t o massive e q u i p a n u l W ,

dnmlnantly medlun-gralned. Hlneralogy Includes complexly twlnned, wel l toned plagioClaJe , aubhedr l l ep ido te and loclll

gdrnct and pyroxene.

82DB099A 56°17802u Peteraburg Kter B i o t i t e Quartz Honzodlwlte--Fol ia ted, med lm-pa lned , C.I. 15. Hlghly a l t e r e d and

132O29'29" 8-2 weathered sample. C n l o r l t e abundant, aaoeaacrry a p a t l t e , opaques m d secondary ep ldo te .

Plagl oc l a se cloudy, a l t s r o d , a o r l c l Cl zed.

8 2 ~ 8 0 8 7 ~ 56°15146n Petersburg ~ t e f ~ i o t i t e - ~ ( l r n b l e n d e ~onrllts--nad~um-grrined, l nequ lg ranu l r r , C.I. 19. outcrop 1s cu t

1 32O08'58" 8-1 by minor qua r t z v e i w .

E2S~loOa 56°20105n Peteraburg Ktef Hornblende-Blotlte Tonallte--foliated, f i n e - t o medlum-walned, Inequ lwanu la r , C . I . 25,

1 32°01'08n 8-1 Sample c o l l e c t e d a t contact between Ktef and TKbs.

82RK77'lA 56°17q06n Petersburg Ktef Hornblende-Blotlte Granodlorlte--Foliated, f i n e - t o medium-grrlnea, apu lg ranu la r , C.I.

132°06'23" 8-1 10. Mlnor primary t p l d o t e . ~ p h e n e m d a p a t l t e . C m o n mvmekl te l n t e r ~ r w t h s .

81 PB032A 56°16'12n Peteraburg Ktef Hornblende-Blotlte Granodlorlte--Well foliated. Inequ lg r#nu lw , medlum-gralned. C . I .

1 3 2 ~ 2 3 ' 1 8. B-2 25. Euhedral, prlmary ep ldo te , n lno r c l l n o z o l s i t e , and a c c e ~ s o r y aphene and apatite.

Mlnor s e r l c l t e a l t e r a t l o n , ox tens lve b l o t l t e a l t e r a t l o n t o c h l o r i t e .

lllRK319A ~ 6 ~ 1 8 ' 2 8 " Petersburg Ktef Hornblende-Blotlte Granodlwlte--nedlm-palned, a e r l o p o r p h y r l t l c p l ag loc l a se . C.1.

132019'58" 8-1 26, u l t h accessory mineral* of ep ldo te . apatite, and mphene. Outcrop cut by very

minor pelgnat 1 t e dl re.

82KR002A 56'29'52" Pe te r sbu rg Ktel Hornblende-Blot1 t e Tonal l te- -Flne- t o medl w-g ra lned , hypldlrmorphlc-granular . C . 1. 25,

132°33'25" B-2 wl th accessory mlnerala of c l l n o z o l s l r e and sphene. P l ag loc l a se wlth a e r l c l t e a l t e r -

a t i o n ,

48

Table 2.--Petro#raphlc descrlptlons of ample 1oaaJltles--Contlnuad.

.- . -- - - - . .

Map Smple Latitude nap Number Nunhr Long1 tuda Quadrangle Unl t Sample descrl pt 1 on

190 82DD205A 5b019123" Peteraburg KteT Blotl tr-Hornblende Tonalltu--Medlm-gralned, porphyrltlc nerlate, C.1 . 31, ulth mlnor

13P10*01* 0-1 eccesswy sphene. Blotl te la partially altered to ohlorlte.

199 82Pel06A 56°15114m Peteraburg Ktef Hornblende-Blot1 t e Cranodlorlte--Follatrd. medlm-gralned, parphyrltlc, C.I. 33 , ulth

132°15145n 8-1 minor epldote and pyroxene. Outorop 1s cut by mlnw quartz velns.

200 1208198A 56°35804n Petaroburg Ktef Hornblende-Blotlte Tonnllte--Foliated. ser la te , inequlgranular . C.1, 25. Secondary

132°19'10" C-1 mphene, epldote and ollnozolalte. Mlnw mount of garnet and apatl te. Swe

localized ser lo l te alteratlon.

201 82P0086A 56O18'22" Peteraburg Ktef ~ l o t ~ t e - ~ o r n b l e n d e ~ o n a l ~ t e - - ~ o ~ l a t e d , tine- t o medlurn-grained, porphyrltlc, C.I. 27.

1 32°09*09" 6-1 ulth minor epidote.

20: 78RS097A 56°25v47n Peteraburg Ktef Biotite-Hornblende Quartz Dlorlte--Foliated, medium- to coarse-grained, polltllltlc

132'01 ' 34" B-1 garnet phenocrysts, C . I . 20, wlth mlnor epldote and aphene. nlnor b io t i te

~ h l o r l t l z a t l o n and cmmon myneklte Intergroutha.

203 82SK090A 56°18'2611 Peterrburg Ktef Blotlte-Hornblende Tonal lte--foliated, lnequlgranular , osrioporphyrl t l c plagloclirse,

132°14q41n B-1 C.I . 25. Accessory rpat l te , aphene and minor secondary epldote. Ulnor amount cT

aerlcite.

2011 BlDBl lBA 56O38126. Petersburg Ktef Blotlts-Hornblende Tonal lte--Foliated, ser la te , lnequlgranular, C.I. 20. Worm-like

132°28'120 C - 2 al tera t ion(?) t o epldote and cllnozolslte. Cmmon myrmeklte intergrowth end minor ser i -

c i te .

20: 82SH134A 56°20157n Petersburg Ktef Blotire Tonal ite--nasslve. equlgrrmular . med~un-grained. c .I. 30. Cmon cuhedral

132°20'19* 0-2 garnet, abundant cllnozolmlte, minor epldote. Accessory aphene and apatl tr . Plaglo-

clase highly nltered t o ser lc l te .

206 82SK089A 56°19v04* Peteraburg Ktef ~ornblendtr -~iot l te Tonallte--Fol~ated, medlum-gralned, inequigranular, aerioporphy-

132°14'90h B-1 r i t l c plagloelase, C.I. 26, with 8ocessory garnet, epidote, and opaques.

231 82SK096A 56°3~110u Petarsburg Ktef Hornblende-Blotlte Grahodlorlte--Foliated, inequlgranular, fine-grained, C.I. 12.

132°19'21" C-1 Accessory sphene. Secondary spldote and c l l n ~ z ~ l a i t ~ r lming hornblende and blo t l te ,

nlnor prlmary epldote. Pla@loclase highly altered t o ser lc l te .

20e 82RK781A 56°18'29" Peteraburg Ktef Hornblende-Blotlte Tonallte--Follated, medlm-gralned, equlgranular, aeriate plaglo-

132O08'39" 8-1 clasr ulth accessory eplaoto. pyroxene and aphene, Outcrop contains 1 percent

elongate maTlc Incluslons and mlnor Eranodlorite dlkes.

2b9 82SK142A 56°04138" Peterabur$ t t e f Hornblende-Biotite Tonallts--Follatod, Tlne- t o medlum-gralned, lnequlgranular , C. I .

13?008v50w A - 1 31, wlth acCsSsOry garnet, cllnozololts and apatl te. Plagloclase has mlnor s e r l c l t e

alteratlon.

210 82SK124A 5t027'1 3" Prtorsburg KteT Hornblende-Btotlte Tonallte--Hedlm-grained, lnequlgranular, C.I. 20, ulth prlmary

1 3 2 ~ 1 9 ' 5 3 ~ 8-1 epldote and accessory sphene.

21 1 8 1 ~ ~ 0 0 2 ~ 56°35107w Pereraburg Ktet ~ o r n a ~ e n d e - ~ i o t l t e Tonal l te - -~edlm- t o coarse-grr~ned, amloporphyrl t l c . C . I . 30, wl th

\ ~ z O U U * ~ B ~ C-2 epidote a s inclusions in b lo t l te . Plagloclase shous mInw alteration t o s s r l c l t e .

21 2 7bRS132A 5 ~ ~ 1 5 ' k 5 ~ Petersburg Ktef Blotl te-Hornblende Tonal 1 te--Fol fated. lnequlgranular , plagloclase porphyrl t l c , hypl d-

132°20133w 8-2 lmorphlc. Accessory Sphene. epatl te, opaques, secondary epldote, and c l l n o z ~ i ~ l t e .

nyrmakltr lntergrowtha common. nlnor mount of serlcitt..

Table 2.--Petrographlo descrlptlons or sample localltles--Continuad.

Map Sample Latitude nap Number UUnb6r Longitude Ouadrangle Unlt Sample duscrlpt Ion

21 3 82RK779A 5 ~ ~ 1 6 ' 5 5 " Patarsburg Ktsf Hornblende-Blotlte Oranodlorl te--Weak 1 lneatlon, rquleranular , Tlne- to nrdlum-grained.

1 32'07 '50" 8-1 C.I . 25. Mlnor accessory mtnerala or aphene, rpatl te. secondary apldote and opaques.

No a1 torat lon or lntergrowths.

214 78DB113A 5 ~ ~ 3 1 ' 5 1 ~ Pstlrsburg Ktef Hornblende-Blotlte Quartz Dlorite--Slightly follalea. medlm Eralnod, hypldlomcrphlc-

133°19112" C-1 granular, C.I. 40. Sphene, cllnozolslto, apat l te ma aparse garnet are acces~ory mln-

erala. Plagloclaae occurs as phenocrysts, mostly as nubheoral laths.

Serlelt lzation common, b l4 t l te and hornblende lntargroun.

215 82PBOTZA 56°16'43w Peteraburg Ktef Hornblende-Rlotlte Quartz Dlorlte--Foliated, medlum- t o coarse-gralned, pOrphyrlt l~,

1 32°0011 4" 8-1 C.I. 39, wlth prlmary epldote and accsssory sphenu and apatl te.

216 B2KRO65A 56O16'36" Peteraburg Ktef Blotlte-Hornblende Tonallte--3llghtly follated, equlgranular, C.1. 30. Accessory

1 32°18'23n 6-1 aphene, mlnor opaques, rpa t l t e snd aeconoary epldute. Mlnor a1 teratlon; feu

myrmaklte Inter~rowths.

21 I 82D8206A 56°16'~6n Petersburg Ktef Hornblende-Blot l t e Tonal 1 te--Fol lated, equlgranulur , medlm-gralned, C . I . 35. Acceg-

1 32°09*23n B- 1 sory sphene and opaques. nlnor bioti te alteratlot1 to chlorite.

218 78RM295A 56°12125n Petersburg Ktef Garnet-Bearlng Blotlte tonallte--Foliated, lnequl#ranular, hypldlmorphlc-granular,

132O20' 32" A-2 C.I. 25, Abundant accessory minerals; aubhc3rrl garnet, well zoned, prlmary and

seconaary epldote. zancrd cllnozolalte, a l m r apatl te and secondarb twinned calcite.

No alteratlon.

21 9 82SK145A 56°04*34* Peteraburg ~ t e r ~ l o t l te-tiornblende Quartz ~ i o r l t c - - F O ~ irted, fine- to medium-gra~ned, inequigranular

132°11'11w A - 1 to porphyrltlc. C , I , 45. wlth fiarnet, cllnozolslte and accrsaory apatl te and sphene.

n lmr mount3 or seri t lzatlon and blo t l te al terlng t o chlorlte. Outcrop contalns

schlleren and xenolltha or country rock.

220 82PB124A 56'07'58" Petersburg Ktel Biotite-Hornblende Quartz Dlorlte--Foliated, medium- t o coarle-malned, serloporphy-

13t014'44" 1-1 r l t l c , C. I. 42, ulth garnet, eplaote and cl lnozolslte. Abundant p l a g l o ~ l a 5 ~ ulth

nerlclte alteratlon. Hornblende and blo t l te al terlng t o chlorlte.

221 82KR064A 5 6 D ~ 6 ' 2 ~ " Peteraburg Kter Blotite-Hornblende Tonallte--Well follatsd, medlum-gralned. lncqulgranular, C . I .

132°14q00n 8-1 42, ulth epldota, aphene and opaque*. Occasional blotl te-rlch areas up t o 8 cm long.

222 62DB189A 56°21*35M PeterlBwg Ktel Biotlte-Hornblende Quartz Dlorite--Hedlum-grained, nerlate, C. I . 48. Minor sphene.

1 32°09154w 0-1 epldote and cllnozolalte. Very altered plagloclase.

223 B2PB122A 56°05'54" Peteraburg Kter Blotlte-Hornblende Monzodlorlte--Fol lated, llne- t o medlurn-grained. C. I . 50, accessory

132°13*12' A-1 sphene and opaques. Abundant eplaote occur3 mostly as l n c ~ u s ~ o n s in plag~ocla$e,

blotl te and hornblende. Blotlte and hornblende lntergroun and seen a3 clumps. Blotlte

al terlng t o chlorlte.

Xtlf fntruslve rocks of Admlrrlty-Revlllagl@o plutonlc belt expoaed on HltkOl. tarmbo and Woronkofakl Islands--Hornblende- - Biotite tonall te, granodlorlte. quartz monzodlorlte and quart2 diorite; equlgranular to sparsely porphyrltlc, ueakly

foliated, medlm-gralned. Local ul tramallc Inclusions. Mineralo$lc features lnclude Zoned, aerlata p l a~ loc l a re , marlc

clwnp, aubhedral epldote and cllnozolslte and rare garnet.

224 8ZPB003~ 56°25*36* Peteraburg Ktll Blot1 te-Hornblende Cranodlorl te--Fol lated, medlm-grrlned, inequlgranular. C.I.

133~38'28" 0-2 20, wlth accessory a l lanl te , end apatl te. Mlnor OpldOte as lncluslons In b lo t l t r .

Potasslum feldspar 13 commonly polkl l l t lc .

Table 2.--PetrowaphlO deaerlpt lons of ample local l tlea--Cnntlnued.

Sample Lmtitude Hap Nunber Longitude Ouedrrngle Unlt Sample descr l pt 1 on

78BC030A 56°22'26w Peteroburg K t l t Hornblende-Blotlte Tonellte--Medlwn- t o coarse-gralnaa, aer loporphyri t ic , C.I. 18, vlLh

1 3 ~ ~ 3 8 ' 5 3 ~ 0-2 primary and aecnndary tp ldo te and acceaaory sphene, magnetite and a p a t i t e . Hlnor

mount or plnglaalase a l t e r l n g t o a e r l c l t e . Chemlcal analyals by rapld rock method.

'IlJRS118A 56O22'51" Peteraburg Ktlf BIotlte-Hornblende Tonalite--Foliated, e q u l p a n u l ~ , aedlm-gralned, C. I . 25. Cmmon

132'33'35" 8-2 a p t l t r lncluslons; epldote and c l l n o x o ~ a l t e a l t e r a t l o n of hornblende, along with mlnor

opaquea. Plagloclase hlghly a l t e r e d wlth cmmon myrmeklLe Intsrgrouths.

81DB129A 56°35859u Petersburg Ktif Hwnblends-Blotite Tonal lte--Col l a tea , Inequlgranular , medlwn- t o coarse-gralnhd, C .I .

132°36'33" C-2 25. Crarded plagloclase porphyrltlc. Euhedral t o aubhedral eplaote a s l n c l u ~ l n n ~ In

b l o t l t e .

19DB192A ~ 6 ~ 3 9 ' 3 0 " Peteraburg Kt11 Garnet-Beerlng Hornblende-Blotlte Tonallte--Foliated, fine-gralned, C.I. 28. wlth

13p45'16" C-3 accessory sphene and ragged prlmary epidote. Plagloclase shows minor a l t e r a t l o n t o

muscovite and clay.

79RS174A 56°33'18w Petersburg Kt11 Blot l te- t lwnblende Tonallte--Foliated, r l l g h t l y porphyrl t lc p l a g l o c l u e , medium- t o

1 3 ~ ~ 5 4 ~ 5 9 ~ C-3 ooarae-gralned, C.I. 24. Hornblende with s i eve t ex tu re , prlmary epldote; accessory

a p a t i t e w d sphene.

79RSl BBA 56°40'09n Peteraburg Ktlf Sphene-Bearing Hornblende-Hiotite tonal Ire--Foliated, equigranular , medl un gralned,

132%2*55" C-3 C.1. 28. Illnor hornblende wlth aleve texture. Acoesaory garnet , opaques. end

prlmary and aecandary epldote. Uyrmeklte In te rg ra r ths .

78BC039A 56°27'00* Petersourg Ktlf Biotite-Hornblende Quartz Monzonite--Porphyritic Inequlgranular.

132~47'28" 8-3 C.1. 15. Andeslnr plagloclase ranges rrcm mostly a e r i a t e t o sparse 1.5 cm. pheno-

crysta . Hlcrocllne forms la rge ( 2 m.) anhudral olkocryata. I n t e r s t l t l a l quartz .

hornblende, and p a r t i a l l y c h l o r l t l z e a b l o t l t e present. Accessory mapnetlte, a p a t l t e .

and aphene.

79D3191 A 56°38'39" Petersburg Ktlf Blotlte-Hmnblende Grenndiorlte--Fa1 l a ted , Inequlpranular, medlm-malnad, C .I. 110.

1 3 2 0 ~ ~ 0 7 " C-3 Hlghl y a l t e red , l r ac tu red rock. Clwnmon secondary epldota, mlnw am0unl.s Of sphens,

opaquea, and cl lnozolsl t e . P l a g l o c l a ~ e hlghl y a1 tered t o s e r l c l t t . Common myrmekl t e

Intergrouths.

B2SH005A ~ 6 ~ 2 7 ' 2 5 " Petersburg Kt11 Hornblende Grmodlorlte--Foliated. lnequlgranular, s e r l a t e , C.I. 29. Minor blot1 re .

1 32°45q04" B-3 Euhedral aphene, mlnw a p a t l t e and opaques. c m o n secondary epldote. Plaelc-

c l a s e hlgnly a l t e red . Myrmeklte I n t e r p c u t b common.

B2SHOO4A 56°26'47n Peteraburg ~ t i r Hwnblende ~ r a n o d ~ o r ~ t e - - ~ a s s ~ v e , aer loporphyrl t lc . C.I. 21. Accea3ory minerals are

132'41 '04' 0-3 euhedral sphene, epat l t e , opaques and prlmary epldote. P l a ~ l a c l a b e 1s hi ghl y a l t e red

t o a e r l c l t e , and contalna minor epldote I n c l u a l o n ~ . Hornblende I s a l t e red t o chlorlLe.

78RM378A 56'25'27" Petersburg Ktlf Hornblende-Biotite Tonal Ite--Hedl wn-grained, s e r l a t e , lnepuleranular. C . I . 25. Eu-

1 32°bj*00n 0-3 hedral rphene, c m o n epidote and cl lnozols1te . Plagloclase 1s hlghl y s e r l c l t l t e j . . Uyrmtklte oommon.

fERM376A 5t025'27m Peterrburp Ktlf Epldote-Hornblende Quartz Dlorlte--Mealum-gralnrd, hypldlmorphlc-granular. Hlnor

132~49'44" 8-3 h l ~ h l y n l t e red b l o t l t e ; mrnblende hlghl y ch l0 r f t l zed . Abundant primary and

aecondury epldote. Plagloclaae hlghly a e r l c l tlzmd. Mlnor ayrnvklte I nteryrouths.

82SHOOLA 5 ~ ~ 2 7 ' 2 3 " Petersburg Ktl 1 Epldote-Hornblende Quartz Monmdlorl te--Serl a te . mass1 ve , hypl dlrm~lrphl c-granular , 132O52'1 3" 8-3 C.I. 24. Accessory mlnerals include aubhadral aphene, and eplaore, P l a ~ l n c l a s r hi#hlv

81 t t red , hornblende and blot1 t o botn a1 tered Lo chlorl L a .

Trblr 2.--Petregraphlc aescrlptions or sample localltias--Continued.

Sample Lat 1 tude nap Nmbur Lon~ltude Prudrmele Unit

82RK727A 56°56'39C Poteraburg Ktif lot^ te-llornb~ende ~onzodlorlte--to1 Iated, intrquigranu~ar , asaim- to coarse-gra~ned,

1 33°1!i141C D-4 C.I. 50. Serlste plagloclane wlth minor mymeklte intsrgrowths. Abundant prlmary and

secondary epldotei a~oeaaory Ophene. opaques and apatltm. -- -- - -

Rtop Intrusive POQkS of Aamlralty-Aevlllaglgeoo plutonlc belt e x p e d on Lindenberg Penlnlula, MitKOr, Rynda, Kadln, Woron-

kolskl, and Yrangtrll Islands. Hwnblende-blotlte tOnallt0 l a porpnyritlc, locally foliatbdl msdiun- t o warse-gralned.

Raru nornrels inclusions. Petrographic tenturea lnolude nerlate plagloclase, epldote md zoned Iarnet, mnd clunped

maflcs.

82KRONA 56°00'47n Petersburg Ktop Hwnblende-llotlte Tonallts--hanlve, aeriporphyrltic, hypldimorphic-granular, C.I.

132O03'2~' 4-1 18. Garnet, apati te and prlmary epldote are accessory mlnerala.

82KR074A 56°29q40" Petersburg Ktop Hornblende-Blotlte Quartz Dlwlte- -Ssrloporphyri t lc plagloclsse, medlm-grained, C.I.

1 32°22110w B-2 28. Accessory aphene, opaques, and c-n clinozololte. Plagi0Cla3e highly altered to

s e r l c l t e . Some myrmeklte inttrgrouths.

82DB103A 56°32'00" Petersburg Ktop Hornblende-Blotite Tonallte--Scrloporphyrltlc. medium- t o coarse-grained, C.I. 35. 132O26'29" C-2 Subhedral sphene, a l lani te with b lo t i te and hornblende inclusions, subhedral garnet,

and cllnozolsite w e accessory minerals. Plagloclase grains are aubnedral laths wlth

epldote inclusions.

82PB125A ~ 6 ~ 0 0 ' 1 8 " Peteraburg Ktop Biotite-Hornblende Diorite--Porphyritic Earnet, inequlgrsnular. flne- to coarse-

1 3 ~ ~ 0 5 ~ 2 9 " A-1 gralned. C.I. 60. Minor accessory minerals or opaquea, nphene and apatl te.

Plagloclase highly altered t o ser lc i te .

Ktoc Intrusive rocks of Adniralty-Revlllagigedo plutonlc belt expored on northern Wrangell, nitkof, Woronkorakl and Etolin - Islands--Garnet-biotite tonall te and mlnor granodlorlte; nonfollrted crwded plagloclase rock, lnequlgranular t o porphy-

r l t l c , flne- to medlm-gralned. Hlneralogy lncludea garnet, el lnoroialte and local muscovlte.

B2DB222A 56'28'24" Petarsourg Ktoc Garnet-Bearing Blot i t s Granodiorlte--Equigranular, rlne-gralned. C. I . 15. Sphene,

132O21 '76" R-2 ~ a r n e t , mostly as inc~uslona, and primary epldots ara aocea9ory mlnerala. Plagloclase

i s suohedral and partly altered t o s t r i c i t s . Ulnor mount or musoovlte aeen a3

lncluslons in plagloclase.

82KR074C 56°29'40w Peteraburg K t 0 0 Garnet-karlng Bloti te Tonallte--Crowded plagioclase porphyry, lnequlgranular. C.I. 16.

1 32'22'1 0" 8-2 Eunedral, lnequlgranular aarnet. Accessory clinozoisite, and apatl te. Plagloclase

well altered.

820e236c 56°24'26c Peteraburg Ktoc Garnet-Bearing Biotl t e Tonal i t6--Equigranular, f ine-grrlned, C.I. 22. Less than - 5

132°14t11" 0-1 percent opaques, euhedral garnet, and epldote conJtltute the accessory minerals.

Epldote occurs as Inclusions in plagloclase md garnet. Prlmary muscovite.

82PB098A 56O~7~43" Poternbure Ktoc Hornblende-Biotite tonal ite--Serioporphyrl t i c plrgloclase, lnequlgranular . flne- to

132"1?*30" a-1 medlm-gralnud, C.I. 12. Both prlmary rna secondary epldote and cllnotoisl te, local

secondary muscovite, and minor amounts of apatl te. sphene and garnet. Plagloclase

highly altered t o aerlclte.

8lSM135A 56°4~157n Peternburg Ktoc Garnet-Bearing Blot l t s Tonalltt--Crowded pla&loclase porphyry, lnequlgranular, C. I. 21.

132°29155n C-2 Dlssemlnated garnet t o 2 m. Accesawy cllnozoialte, rpnene ma secondary muscovite.

Mlnor blotl te alteration t o chlorite.

Trblr 2.--Petrographic deacrlptlona of #ample local Itlss--Continued.

Sample Lat l tude MOP Umber Longltude Qwdrangle Unit S m p l e deacrlpt lon

BZPBlOOA 56'26'39" Peteraburg KtOc B l o t i t s Tonallte--Serloporphyritlc plagloclase, lnaqulgrenular, f lne- t o nediun-grained.

13914'49" 8-1 C.I. 20. Abundant o l l n o ~ o l s l t e ; mlnw epldote present. Apatite and sphene caninon

I S in01 wlOn3. Euhedral snrnet occurs as lncluslona In Blot1 t e . Hlnor myrmekl t e

intergrowths present.

82RK806A 56°25'52* Peternburg K t 0 0 Garnet-Bearing Blot i tkHornblsnde Puartz Dlml te--Porphyrl t l o garnet. lnequlgranular , 1 3 ~ 1 2 ' 0 0 " 8-1 f ine- t o medlua-grained, C.1. 25. Crwded plagIoalase u l th BlnOr a s r l c l t e a l t e ra t ion .

Accasswy aphend, opaques and cl inozoIs1te .

NJOJ In t rus ive roovo of Adalralty-Revllla~lgeOo plutonlo be l t expoaed on Lindenberg Penlnaulr , Kupreanof Ialand, southwestern

n l tkof . Yoronofarl and northern Z a r ~ D 0 Ir land. Blotlte-epldote-hornblende quartz monzodlorlte; loca l ly fo l i a ted .

plagloolrso porphyrl t lo with f lne- t o medium-gralned grounO.rss. Hlnrraloglcal f ea tu res Include prlrnary and aecondary

epldote. a e r i o l t a a l t w a t l o n of plagloclase oores, and euhedral hornblende.

BOSK129A 56°48'41 " Petersburg ~ q o p nwnblenae-81otlte Granodlorlte--~qulgranular , hypldlmorph~c-granular , medium-pained,

1 33°06'48" D-4 C.I. 18. Crowded plagloclaae with minor r l t e r a t l o n . Ulnor epldote and acorsswy

a p a t l t e and opnques.

79AF141 A 56°50'53* Peteraburg Kqop Blotlte-Hwnblende Granodiorlte-Serioporphyrltlc plagloclase, Inedlm-grained, C.I. 25.

1 32°16'37" 0-3 Aoceosory a p a t l t a , aphene, euhedral garnet , and epldote. Plsgloclase l a well a l t a rad

t o o e r i c l t e ,

82RK710A 56'23'09" Peteraburg KqDp Hwnblenae-Biotite Cranodlarite--3erloporphyrltlo plaaloclese up t o 9 mm, mesalve, C . 1 .

1 3P46'40w 0-3 Z l . Accessory mlnerala include opaques. euhedral aphene. zoned a l l r n l t e , and euhedral t o

aubhedral epldote seen large1 y a s lncluslons In plagloclase. Plagloclase contalro mlnor

s e r l c l t e a l t a ra t lon . B l o t l t e pa r t ly a l t e red t o ohlorl te .

80SKl48A 56O42*36* Peteraburg Kqop Blotlte-Hwnblende Quartz Dlorlte--Foliated, tabular t o equant porphyrl t lc plagloclase.

1 32°51'21* C-3 medim-Brained, C.I. 26. Dlssemlnated pyr l t e and cnalcopyrlte. Secondary and prlrnary

mpldote, accessory a p a t l t s and aphene,

78RM254A 56°46*~8n Petersburg ~ q o p ~ l o t i t t - ~ o r n b l e n d e Quartz lo rite--~ollated, porphyrl t lc , medium-grelned, C.1. 20.

1 3 3 9 3'47" 0-4 Prlaary and secondary epldote, accesswy aphene, n p a t l t e and opaquea. Hyrrneklte in te r -

growth3 and plagloclase Ulth s e r l c l t e r l t e r a t l o n .

81SHO56A 56°47'26" Peteraburg Kqop Blotlte-Hornblende Granodlwi te--Slightly f o l l a t e d , a e r l a t e , medirun-gralned, C.I. 25.

1 3 2 % ~ * Z O * 0-3 Accessory aphene, a p a t l t e . opaque3 and secondary epldole. Mymekite Intergrouths.

Plagioclase a l t a r l n g t o clay and muscovite.

8OSK594A 56°52'27" Petersburg Kqop Blotlte-tlwnblende Quartz Dlori te--Pwphyrl t lc plaeloclaae. medlurn-grained. C.I. 28.

1 33°02'23* D-4 Mlnor amounts of garnet , aphene, and epldoLe. Plagloclase a l t e r l n g Lo rnuscovlte and

clay.

828801 41 56'44 '02" Peteraburg Kqop Blot1 ta-Hornblende Quartz Dlorl te--Serloporphyrl t lc plagloclase, medium-gralned, C.I.

1 3 3 ~ 0 1 '54" C-4 28. Zoned plagloclase. Accessory sphbns and a l l a n l t s ; mlnor epldote occurs a s

Incluslonu.

fBSH053A 56'31 '06" Peteraburg Kpop Hornblende Quartz Dlwl te--Porphyrl t i c . Inequlgranulmr, C.I. 30. Large, zoned pheno-

l 33°0~145" C-4 a y s t s of plaeloclase up t o 1.5 n. Flne-gralned quartz. potrlalum fe ldspar ,

and plagloclase. Hlnor amounts of epldote, aphene m d opaquea.

82PB023A 56'42'55" Petersburg Kqop Blotlto-Hornblende Quartz Dlorl tc--Serlopyrl t lc plagloclase. very f lne - r o flne-gralnad

1 33O01 '45" C-4 ~ r o u n 4 ~ 1 a 3 s of maflca, quartz end potassium feldspar , C.1, 18. Prlmary epldnt a , accru-

aory aphene, a p a t l t e and opdques. Plagloclase ahouv mlnor Lo moderat e a l l e ra1 lc.11.

Table 2.--Petrogrrpnlc descrlpt lona or a m p l e laoalltles--Continued.

Sample Lal l tude Map Yunber Long1 lude Quadrangle Unl t Sample deacrl pt l on

78AF142~ ~ 6 ~ 2 3 ' 2 0 ~ Peteroburg ~ q o p Bio t i t e Quartz ~ i o r l t e - - ~ w p h y r i t i o plagioclase, medlua-grained, C . I . 40. Zoned pri-

13i?2h8 32' 8-2 mary epldole and abundant o l l m z o l a i t e . P l a ~ l o c l a a e oental M abundant

lnclrulons and l a a l t e red . Fmi l a rge ruhedral npaquer present.

In t rus ive rocks of A-lralty-Revlllaglgeda plutonlc be l t cxpmed on Etol ln I l l and . B l o t i t e t o n l l l t e , quartz d l o r l t e and Il.e @-anndlorlte a r e f o l l a t e d . porphyrl t le . and n o d l u - t o m v s r p & l n e d . laaturn include tmplex ly tulnneo plaglocIase,

ch lo r l t l zed b l o t l t e , absence or hornblende. and the presence of #Wnet.

18RS082A ~ 6 ~ 2 7 ' 4 2 " Petersburg Ktgp Garnet-marlng Blot1 t o Tonal lte--Fol l a ted , porphyri t ic , medl un- t o c o a r s e r a l n e d , C.1.

1 3 P 0 3 ~ 0 3 " B-1 10. Cllmzo1sltcr, aphena, I w n e t m d opaques a r e the accesscry mlnerala. Plagloolaae

-only a l t e r e d t o s e r l c l t e . b i o t i t e pa r t ly a l t e r e d t o ch lo r i t e .

78un258~ 56°26v41n Petrrsburg Ktgp Garnet-bearlng Blo t l t e tonallte--foliated, porphyrl t lc , lnequlwanular , C.I. 13.

132°04'26' 8-1 Anhedral c l lnozo la l t e , sphene ha lncluslona. garnet , and a p a t l t e a r e the accessory mln-

e ra l s . Plagloclase 1s Eenerally f resh with mlnor myrmeklte intergroutha. b l o t l t e

shous mlnor cn lo r l t l za t lon .

81DB161A ~ 6 ~ 0 0 ' 0 0 ~ Petersburg Ktgp Blotlte-Hornblende Quartz hnzodlorlte--Foliated. graphic intergrouths common, feu

132°15*27" A-1 a l e r o l l t i c cav l t l eo , r e r l a t e , C.I. 37. n a t l c mlnerala include clinopyroxene and

alnor amounts of arcondary and primary epldote. Accessory a p a t l t e , aphene, zircon

and opaquos. Mlnor c h l o r i t e a l t e r a t l o n . napped lnoorrcct ly a s Tmme In Brew and

o thers ( 1 984).

82SK146A 56°00 '0~n Petersburg Ktgp Blotlte-Hwnblende Quartz Dlorlte--Medlm-grained, hypldlomorphlc. inequlgranular,

132°12'12w A-1 C.I. 47. Accessory a p a t l t e , aphene, magnetite and pyrl te . Plagioolase has a m b

secondary a l t e r a t l o n t o a e r l c l t c . Mapped incorrectly aa Tme In Breu and o thers

(1984).

!92 Intrueive rocka of ~ a m l r a l t y - ~ e v l l l a g l g e d o plutonla be l t exposed on northern Lindenbet-$ P e n i ~ u l a and o e n t r a ~ nl tkof

Is land. Pyrexene-blotlte-hornblende quartz monzodlorlte, quartz d l o r l t e , monzodiorlte and d l o r l t e . Locally f o l l a t e d ,

equlgranular, medlun-gralned. Maflc Inclusions, pe@matltla velru m a dlabase dlkes present. Petrographic f e a t w a s

Include p n l k l l l t i c hornblende, twlnned. zoned and crwded p lag loc lwe , and hornblende as the domlnant marlc n lnera l .

82RK712A 56'41 *2Bn Petersburg Kqo Pyroxene-Blot1 te-Hornblende Quartz Monzodlorlte--Fol l a ted , equlgranular t o blot1 t e

132047'20~ C-3 pwphyr i t l c , C . I . 46. Aocesaory aphene, opaques and sparse epidote. Pyroxene l a

p e r t l a l l y a l t e red .

82RK725~ 56°58'40" Peteraburg Kqo Blotlte-pyroxene Quartz Monzodlorlte--Maaslve, f lne - t o very f ine-gralned, equlgran-

1 33°09'42" D-4 u l a r . C.I. 10. Accessory opaquea lntergraun wlth pyroxene. Myrmeklte lntergrouths.

8ORSl 95A ~ 6 ~ 5 9 ' 3 8 ~ Patarsburg Kpo Blotlte-Hornblende Quartz Dlorlte--Foliated, porphyrl t la plaglocl&le, Ocrlate , C.I. 42.

1 3 3 ~ 0 1 '12" 0-4 Prlmary and aeoondary epldote, minOP pyroxene and accesswy a p a t i t e , opaques m d zol-

a l t e .

bOSKS87A 56'53'59" Petarsburg Kqn Hornblende Quartz Uonzodlorl te--Medlm-gralned, hypldlmorphlc. lnequlgranular, C.I.

133"02'52" D-4 51. Prlmary and secondary mpldote, a lnor pyroxene. and acceaaay sphene, a p a t i t e

and garnet. Moat plagloolaae contalna clay and muaoovlte a l t e r a t l o n .

80SKlZBA 56'55' 13" Petersburg Kqo Hornblende-Blot1 t e Quartz Monzodlori te--Foliated, aerloporphyrl t l c p l a g l o c l u e , 1neqUl-

133O01 ' 1 2" D-4 granular , C.1. 49. Otner mlnerals we pyroxene, rphenm. opaque8 and epldote. Minor

a l t e r a t l o n of plagloclasr .

Kdl - I n t r w l v e rocks of Admlral ty-~evl l laglgbdo plutonic be l t exposed on Woeuodskl Ialand. Hornblende d l o r l t e , quartz di0-

r l t e , and mlnor t o n a l l t e . Cledlum- t o very coaratr-grained, e q u l p a n u l a r ; weathers l l g h t t o dark green; hlghly a l t e red t o

epldote- and ch lo r l t e - r i ch rocks.

Table 2.--Petrographic descrlpt lona of a m p l e local it lea--Cont lnued.

-- -

Smpl e Lat 1 tude nap Nunber Long1 tuds Quadranale Unl t Sample descript ion

-- - - . . - . -- -

79SH113A ~ 6 ~ 3 3 ' 2 5 " Petersbur J Kdi Ueta Quartz Dlorl te--Greonschlst fbc les nlneralogy; non-fol la ted; re1 l c l [email protected]

133O04'26" C-4 texture. Approxlmatsly 95 percent reorys ta l l l zed . Ac t lno l l t e , b l o t l t e , and ch lo r l t e

have replaced hornblende; plagloclrse has rec ry3 ta l l l eea t o epidote and ch lo r l t e ;

aagne t l t e has laucoxunu rlms,

Varled ml@natitlo rocks. malnly bgna t l t e and irregular banded gnelss. Exposed In mnes between hornblende-blotlte

t o n a l l t e and granodlorl te unl t (Kts f ) . and t h e metamorphosed Stephens Passage Group. Gr rn l t io leucosomex resemble main

rock types In uni t Ktef; ths metamwpnlc melasomes a r e f lne- t o medlun-gralned b l o t l t e hornf r l s , s c h l s t ~ and

oemlsChlst3.

82SKlU4A 56'04 '19" Peteraburg Kmgf Blot1 te-Hornblende Quartz Dlorlte--Fine- t o medlm-gralned. Inequleranular a e r l a t e .

132°t0103n A-1 C.I . 55, Two perlods of mlneral g o u t h indicated: zones of opaque lnclualons ul thln

hornblende; two s i z e populations of blot 1 t e . Anhedral t o subhedral plagloclase, Inter-

a t l t l a l quartz , and accessory a p a t l t e and spnene,

Kie netamorphosea Stephens Paarage Group RoCka exposed on Llndenburg Penlnaula md Kupreanof laland-la re en atone and green-

s c h i s t ; aubgreenschlst t o greenacnist f a a i e s rocks, domlnently f lne- t o mudlum-grained, poorly ro l l a ted . S m e r e l i c t

pyroxene-phlrnocryJt-bearing epldote-albi te-chlori te greenstone.

71A8g247 56°12'22n Petersburg ~ s g netavolcanic--semiscnlst t ex tu re ; ~ e e n m c n i a t - ~ a c i e s metamorphosed. netamorphlc mpni-

132°25'35" A-2 bole pseudomorpha a f t e r volaanlc hornblende and(?) cllnopyroxene; brown b l o t l t e and

epldote Secondary f r m hornblende. Qlne-gralned a c t l n o l l t e , c l lnozo l s l t e , parches of

plagloclase, and sparse quartz make up p a r t l a l l y sheared groundmass. Chcmlcal analysls

by rapld rock method.

78AF127B 56°44'21 " Petersburg Kag Re1 lct-Auglte Greenstone--Massive, with greenschist f a c l e s secondary mlneralogy.

1 33°05'00tu C-4 Rel lct aug l te phenocryata (av. 2.5 mm.) have been replaced by aggregates of a c t l n o l l t e

and green b l o t l t e . Matrlx contalns c l lnozo l s l t e . b l o t l t e , a c t l n o l l t c , an4 xenomorphlc

plagloclase. Accessory sphene. Outcrop shows local tuff-breccla I rementa l t ex tu re .

Chemlcal ana lys l s by rapld rock metnod.

78~F127A 56°~4121n Petersburg ~ a g ~ e l i c t - ~ u g l t e ree ens tone--30 percent r e l i c t phenocrysts nou replaced by act inolf r e .

1 33°05'00" C-4 b l o t l t e , and c a l c l t e . Ac t ino l l t e , b i o t l t e , and epldote fwrn glomeroblasts wlthln a

flne-grained granular matrlx of the lame mlnerals. Acceasury sphrne.

Ks3 - Metamorphosed Stopnena Passage Group Rocks-~Schlst and nornrels; greenschlst and a lb l t e -ep ldo te t o hornblende-hornfcla

facloa rocks, derived f r m t u r b l d l t e s and re la ted rocks. Orlglnal t ex tu res and s t ruc tu res general1 y pre3rrvrd. Locally

f o l i a t e d , common omposl t lonal layerlng and a m e clearcut thermal aureoles.

82KR055A 56'21'23" Petrrsburg Kss Blotlte-Quartz-Feldspar Semlschlst--Very f l n e - g a l n e d ; ro l l a ted . Porphyroclaata of

1 3 2 ~ 1 7 ' 5 3 ~ 8-1 plbaloclase and quartz a r e urapwd by a f o l l a t l o n of elongate Clots or a l o t l t r , chlor-

i t e , and allenad quartz. l d l o b l a s t l c garnet present. Inferred graywdcna p ro to l l th .

81S~137A 5 P 4 1 '30" Peteraburg ~ s s ~lotlte- el as par-~uartz ~ e m l 9 c n l s t - - ~ l n e - t o medlm-pal nee; hornfels lc an0 fo l i a ted In

132~41 '08" C-3 t ex tu re , Creenscnlst r ac les metamorphlc r l n e r a l a Include: a l b l t s , quartz , Dlot l ta .

c l inoxolsl t e , ch lo r l t e . an4 uh l le mlca along u l t h carbonaceous maller .

82KR064B 56°16'20" Peteraburg Kss Hornblende-Quartz-Feldspar Hornfala--Flne-grained; laymred, with granoblast lc leuc-2-

132°14'00v 8-1 o r a t l c mlnerala. Craenschist/mphl Do1 I t e f ac les metmorphlc mlnerals Incl uor: Pla-

g loc laa r , quartz , hornblende, po lk l lob las t i c garnet , o l l m z o l s l t e and sphrne. Thln

rec t lon contains 0.6 mm. vcln of c a l c i t e , c h l o r l t e , bnd quartz . Sample f r m 0.25-

' meter-tnlck inclusion In a pluton.

Table 2.--Petrographic deaerlptlons of ample localltles--Continued.

nap Nmber - 278

Sample Latl tude Map r m b r Long1 tude Quadrangle Uni t Sample deswlption

82KR0538 5 ~ ~ 2 2 ' 1 3 ~ Poteraburg Kos Felaaprr-Calclte-Quertz Semlschlst--Fine- to medlm-gralned, polklloblastlc blotl te;

i 3Pl6'29* B-1 moderatel y we11 foliated. Quartz and oalcito dominant with very tlne-gralned unite

mica laths p4rallel t o follat lon. Aeceaaory rpheno andopaquea.

8 2 ~ ~ 0 5 1 A ~ 6 ~ 2 2 - 5 5 " Petersburg ~ s s Carnetiferoua. Quartz-rloh phyllits--very fine- t o tine-erained~ we11 fol latrd; por-

13:O15'23* 0-1 phyroblastlc. Common 1 mu. garnet porphyroblrsta In r chlorite-auaeovl te-quartz-

r lch matrix. Contains elongate quartz-ch~orl te-pyr i te(?) ga ina orlented at nngls t o

fol latlon. Acceaawy c l lnozolsl t e , aphene, and tourmal lne. Carttonaee~us layurs may

deflne aedlmentary layering.

78RM290A 5b020105* Petersburg ~ s s Re1 let-bug1 t e ~etavolcanl c--Very fine-gained matrl x of granular t o tabular epidote , 1 3'c02~'05' B-2 quartz, aubldloblastlc b lo t l te , ac t lnol l te , chlorite, and aphene. Pyroxene pheno-

oryats have been replaced by ac t lnol l te , b lo t l te , quartz and cpldote. Claclte patcnes

and atrlngers m a n . Crude1 y tollatad.

El! Metanorphesed Stephens Passage Croup Rocks--Subgreenschlst and greanschlst faclea phyllltes and grayuackes. Dmlnantly

vary f lne-grained, dark-gray weathering, carbonaceous c h l o r I t e - q u ~ r t z - ~ ~ l d ~ p W phylltto; rune lnterlayered grayuacke;

local layers and lenses of l lght- t o dark-green ueatherlng chlorite-rich phylllte.

71 ABg260 56°38e04* Petersburg ~ s p etav volcanic--very flne-grained foliated matrix with actlnol i t e pseudmorpha of vol-

132056'50n C-3 canlc pyroxene(?). Dreenschlst taclea retamorphlo mlnerala Include: actlnoll te, epl-

dote, plagloclase, green b lo t l te , chlorlte, and minor quartz. Chemlcal analysls by

rapld rQCk method.

80SK150A fr6Ou1 33- Peteraburg Krp Epldote-Chlorlte Phylllte--Flne- t o coarre-gralned, follated, md bandea. Approxl-

1 3j001 '01 C-4 mately 5 percent dlssemlnated euhedral pyrite llneatea along follatlon. Ulnor

pyroxene.

Kuk - Intrusive rocks of Klukwan-~uke plutonic belt expoJed a t Kane Peak, northern Lindenberg Penlnaulr. Ultramaflc complex

or a ) wehrllte - masslve t o locally layered. mealum-gralnea, part lal ly aerpentlnlzed, scattered lncluslons ot cllnopy-

oxenr; b) dunite - grades from wehrllte, part lal ly serpentlnlzed, medlm gralned. usually gray t o dark gray; c) ollvlne

pyroxenlte - masslve t o locally layered. medium-grained. Forms narrou discontinuous zone around margln.

8OS~580~ 56°59'40w Petersburg Kuk Ollvlne Pyroxenlte--Hedlm-palned, hypldtmorphlc-wsnular, lnequl@ranular, C.1. 90.

1 ~ 3 ° ~ ~ ~ 5 7 ~ a 0-4 Domlnont pyroxene 1s cllnopyrorene. Dlsssalnated acceaswy p y ~ l t e . Ulnor blotl te.

moderate1 y altered plagioclase and aeoondary eplmte . Clusters of phlogopl t e unevenly

dlstrlbuted. Hlghly magnrtlc in hand ample. . -- -

Kht, lnrrvslve Pocks of Klultuan-Duke plutonlc Delt exposed on parts ot Woronkofakl, Mltkot md Kupreanof Islands. Horn-

blendlte-hornblende gabbro; locally composlt10nally layered, tine- t o medlun-grained, grayloh-green to black In color.

78AF197C 56°12*50m Peteraburg Khb Blotlte-Hornblende Meta Quartz Dlorlte--Flne- t o medium-gralned; hypldlwnorphlc lnequi-

1 32°18'00" A-1 granular. C. I . 70. Hornblende polklll t lca l ly Includtrs biotl te and contalns oriented

opaque lncluslons. Brwn blot l te rluned by Ilmenlte, aerlclt lzed plagloclase wlth

clear ovrrgrouth rlms, and anhedral quartz present. Accessory garnet, apatl te. and

magnetlta.

8lSK170A 56°11*11" Peteraburg Khb Blotlte-Hornblende Quartz Diorlte--Flne- to nedlu-pr lnod; porphyrltlc. PlagloCla~e

1 3 ~ ~ 1 2 * 3 3 " A-1 phenocrydts with ~ 1 l n o ~ 0 l a l t e md aerlplte centers have olou ovwgrouth rim. Horn-

blende has actlnol l t e rlms and allgnrd opaque l n c l w l o ~ . Aooeoowy magnetite and

aphene .

78AFl u6C 56'23'17" Pmtersburg Khb Hornblendl te--No thin sactlon. Fleld notes lnalcate "dark green, very rlne-grained

1 32°26“18u 0-2 hornblcndlte." Other thln aectlona t r m ama outcrop also contaln cllnopyroxene.

ollvlna, and orthopyroxene.

table 2.--Pstropaphlo deacrlptlcns of ample local Itles--Continued.

Map Nmber

. -- - - - -- .-.

Sample Latl tude nap Nmber Longitude Quadrangle Unlt Sample deawiptlon

82F1~708~ 5 ~ ~ 2 4 ' 3 9 " Peteraburg Khb Harnblende Gabbro--Flne- t o medlun-gralned; poorly foliated; inequlgranular . Elongate labradorlte plagloclaae laths contain secondary c l lmzola l te and sar lc l te ,

are partly recrystalllzed. Hornblende i s ~onmonly tvlnned, has brown centera, and

lncluslons of apati te and opmques.

78MOO8D 5 ~ ~ 2 2 ' 5 5 ' Peteraburg Khb H~nb lend l te--Pine- to medlm-gralned; hypldimorphlc ~ubequigranular . C .I. 99.

1 3 ~ ~ ' / ~ 0 0 ~ 8-2 Hornblende lo omon ly twinned and has opaque lncluslorm. Blotlte, ap r t l t e , and

aphene are l n t e r a t l t l a l . H l ~ r aeoclndary ch lwl t e and c l lnomls l te .

80DBO35A 57°03'35n Sundun Khb Plagl8clase-Hornblenae Pspatlte--Coarse- t o medlum-gralned; hypldlmwphlc lnequl-

133O51 l17" A-6 ~ ranu la r i hornblende polkl l l t lc . C . 1 . 70. Hanblonde subophltloslly encloses plagl-

oclase, magnetlte. and cllnopyroxene. Anaeslne t o labt-adorlte plagloclase wlth

secondary ae r l c l t e and epldole alteration. aubophl t i c cllnopyroxene, b io t i te , and

aphene also present. Hinw chlorlt l tat lan.

81DB242C ~ 6 ~ 5 3 ' 1 6 ~ Petersburg Khb Hanblendlte--Fine- t o medlm-grained; equlgranular. C.I. 98. Subhedral hornblende

132'55'43" D-3 I s ccmmonly tulnned and contalna nunerow apat l te lnoluslons. In t e r a t l t l a l nlagnetltb

and apat l te , and sparse aewndary chlWlte. aphene, and epldote arc present. Rock

appara relatively unaltered and fresh In thln oectlon.

82RK70BA 5b024'39* Petersbur~ Knb Hornblendlte--Plne- t o mediun-prlned; hypldlmwphlc granular wlth a poorly developed

1 3 ~ ~ 3 7 ' 4 9 " 0-2 follatlon. C.I. 99. Poorly rllgned mubhedral hornblende contalru very flne-gralned

magnetlte Incluslona, and i s part ial ly recrystalllzed t o pale amphibole. Cllnopyroxene

altered t8 calcite. Sparse chlorlte and ophene present. -- . - -

K J S V Brothera VolcanlcslDouglas Island Volcanlos--Augi te-bearing f l w s , volcanlo becc l a, and lnteroelated tu f f , volcanlc - grayuacke, pnylllte and slate. Andeslte t o probably basaltlc cmpoaitlon, r e l i c t augite phenocrysta, probably 8 feu

thousand meters thlck. Indlvldual flou w breccla unlts as much as r feu hundred meters thlck.

71Aagz32 56011 ,12" Petersburg Usv Andealte Brecclr--1nhanogeneous In graln alze, percent phenoorysts, and amount of

1 3 ~ ~ 4 2 ~ 1 0 " A-3 devltrlf lsd glass. Andeslne t o ollgoolsse plagloclaae l a ser la te and cllnopyroxene

foms phenocrysts. Devltrlfled glass and oryptocrystalllne aa ter la l make up

20 percent of thln sectlon. Vory altered. Chemlcal analysla by rapid rock method.

79DB115A 56°05'46" Petersburg KJgv Basalt(?)--Pwphyrltlc wlth an lnteraertal poundmass. Phenocrysts are cllnopyroxene

1 3 2 ~ 3 5 ' 4 6 ~ A-2 md altered plagloclaae. Growithaas of plagloclase ~ICPOlites, feu amall cllnopy-

roxene glcmerocrysta, and opaques. Secondary celedonlte(?), zeoli te. and prtthnlte

f l l l lrregularly ahaped amygdules.

71ABg231 56°07t30v Petersburg KJav Llthlc tuff--Volcanic claats (90 percent) are pwphyrltic, pllolaxlt lc. and hyaloo-

I 32O42.00~ A-3 pnlt lc, u l th -on phenocrysts of ellnopyroxene, al tered plagloclase, and hornblende.

Clast groundmass la of mlcrolltes ma cryptocrystalllne materlal. Secondary mln-

era ls (15 peraent of tnln section) lnclude chlorlte, ca lc i te . and ( 7 ) pumpellylte.

Chemlcal analyala by rapld rook method.

71ABg256 56°27'30" Petersburg KJsv Metatuff--Frapental trxture wlth pyroxene(?) pheno0ryeto replaoed by pseudomwpns or

1 3 ~ ~ 3 ~ ~ 3 5 " 8-2 pale mphlbole. Plagloclaae laths are sunedral; r a t r l x dwlnantly very rlne-gralned

epldote. Secondary green b lo t l te , chlorlte, an0 #parse ca lc l ta present along ulth

accessory opaques. Chemical rnalyslr by rapid rock methed.

BUDD-001 56°08'2bn Peteraburg KJsv Baaalt--Pwphyrltlc ulth abundant phenooryats af dlopsldla auglte, 3 t o 5 mm In

1 32°43'30m A-3 dlmeter , and 2- t o 3-m labradorite laths. Groundraass of amall labradorltr

la ths , cllnopyroxene wanules. md magnetite gralns. Mlnor chlorlte alteratlon.

Method of chemical W~llYsls not apeclfled.

Table 2.--Petrogaphlo desarlptloru of ample l m a l Itlc3--Continued,

sample ~ a t l t u d e map l u b r Long1 tude Quadrangle Unlt Smplo Cesorl pt Ion

71Mg230 56°07'00" Petersburg KJsv Altered Llthlc tuff--Altered voloanlc fragnents and orystals In an altered crypto-

1 32°22t00n A-3 crystall ine matrlx. Volcanlc lralg~ents contain phenomy$tr ot patchy recrystallized

hornblende, cloudy plagloclaae, and pyroxene. Seoondary apldote, chlorlte, calclte.

red-brwn alca. and sparse devltrlf led glass present. Chemlerl malysla by rapld rock

tgRSll5A 56°09t18u Petwaburg KJBV Volcanic ~reccla- -~ngular t o mubromded l i t h l c volcanlc olasts average 2 nun In size

13940 '52~ A-3 and are olmllar In cmpoaltlon. Frements are pwphyrltlc hyaloopllltlc with altered

plagloolrse, oalolt@-altered cllmpyroxene, and anhedral opaques. Matrlx 1s danlnantly

wyptocrystalllne wlth very line-gralned opaques, mlcrollter, chlorlte, and altered

glass In patohes. Greater than 7 peroent calcl t e a1 terallon.

- .-

KJss SepOur Canal Fomatlon--Craywacke, s la te and mlnor oonglaerate. Cmposed mostly of volcanic debrls. ConElmerates - w e pDlymlctlc and oontsln grml t l c clasts. Moat are tutbldl tes wlth wfnmon sedimentary atructures b u t Teu dlractlonal

features. Probably a teu thousand meters thlok.

71Mg229 56°06'28h Peteraburg KJas Baaalt--Holoorystalline; porpnyrltle wlth Intergranular @oundnasa. Twenty percent

13~42 '00" A-3 euhedral mncentrlcally-zoned auglte and altered plagloolase. Feu ma l l e r ollvlns(7)

phenocrysts replaced By owpentine, chlorlte, pumpellyl t e , and chlwophacl t e ( ? ) . Rock

la altered; lncludes up t o 7 percent secondary chlorlte. Accessury opaques. Chemlcal

analysls by rapld rock method.

7lABg242 ~ 6 ~ 0 6 ~ 0 0 ~ ~ Petersbwg U s 8 Hornblende-Cllmpyroxene Andeslte--Porphyrltle wlth p l la tsx l t lc groundmass. Labrador-

132O41 '40" A - 3 l t e plagloclase phcnocrysts. along wlth a feu cllnopyroxene glmerooryats make up 17

percent of rock. Grouncbnaas lncludel plagloclsse letns, Worn hornblende. sparse

c11nopyroxune and quartz, and magnetlte. Moderate cnlorlte al teratlon: few calclte-

f l l l e d mygdules present. Chemlcal analysls by rapld rock method.

nzv - Greenscnlst. greenstone, phyll i te, and minor semlschlst aetmorpho3ed f r a volcanlca located along Ouncan Canal and on

Woeuodakl ~d Znrmbo Islands. Locally plllov breccla. sgglmerate f l o n and poaslble tuf fs . Locally abundant r e l l c t

pyroxene phenocrysts. Probably several thousand meters thl ck.

81SHOOBA 56°27'25h Peteraburg Mzv Metavolcanlc--Poorly follated. Actinolite and chlorlte pseudanorphs replace igneous

132O55'42" 0-3 hornblende. Matrlx 1s very rlne-gralnsdi granular wltn epldote, abundant ch lwl t e ,

rewystall lzed plagloolase, and 5 percent nagnetlte wlth leucoxene. Sparse calclte.

I nhogrneorcl outcrop. ~~-

Hornblende gabbro md pyroxene gabbro of northeast Zarembo Island. Uedlum- t o very coarse-gralned ulth s a e lnter-

a t i t l a l aultldel cut by d l ~ e s of quartz d l w l t e .

82SK002A 56°19'1 9" Peternburg Uzgb Metadl w l te--Re1 let lgnmus texture. Very tlne- to medl m-grrlned. Creenschlst tacies

i 32"39'3rw a-2 netmorphlc mlnerala lnclude rc t lnol l te pseudanorphs af ter lgneuus hornblende, reurys-

ta l l tzed plagloclase, epldote, quartz, and b lo t l te u l th r u t l l e needles. Contains

acaeaaury magnatitu.

I h v Hyd goup volcanlcs exposed near Duncan Canal, on Castle Islands, Woeuodskl Island and on Zarmbo Ialand, Felalc and - lnternedlate voloanlc flows and breccla, llmeatone and argt l l l te . Doralnantly very-flne t o Cine-gralncd, chlorlte-

quartz-muacovlte-feldspar pnylllte. Also uune rssoclated dark gray thln-bedaed oarbonaceaua mudstone, s l l t s tone , and

llmertone. Thlckneas probably several hundred meLera.

60SK153A 56°32'46* Petersburg k nv Greenatone--Greenschiat faclea ml nerrl assmblaga includes actlnol l re , as abundant

133~02'23" C-4 anhedral clota. a lb l te , el lnozolslte, cnlrrrlte, calcite. quartz, and spncne. N~ln-

follated In thln aectlon.

58

TnWe 2.-Petrograpnlo dercrlptlons of sample localltles--Continued.

Hap Sample Latltude nap Nunber NmMr Longl t uda Quadrang1 e Unl t Sampla descrlptlon

Tdr - Intrusive Rock3 O r BehPl Canal Plutonlc Bolt--Rhyolite and related rocks; generally rlw-banded, locally quartz por-

pwphyrltlc; occurs In broad rwarn or dlkes fran 0.5 Lo a few meters wlde wlth l l t t l e lneluded wuntry rOck. Feu

plugs occur along atrlke.

301 RZKR07OA 56'32'55- Ptrlersburg Tdr Mlcrogranlte--Quartz porphyrltlc with common mlcroprphlo and panopnyrlc quartz-alkali

1 3.2'05 1 33" C- 1 relaapar lntergroutm. Alkall relaspar also colnraon na aloaerocrysts which leas

ooaronl y enoloae plagloclaso (aodla andealne). Sparse primary b lo t l te and muacovite~

apherulltesi 15-muteP-thl~k 0111 In outcrop.

305 A33125 56°30'35* Petersburg Tdr Rhyollts Porphyry (Amax sample--Age data only). Other descrlptlve lnfwcatlon and

132°03'l~n C-1 geochemical values not lncluded In t h i s report 1. (appro*.

Intruslvv rocks of Behn Canal Plutonlc Belt expoaed only on north ride of Groundhog Ba~ln--Chlorite wanltsr hwogenous,

flne- t o mealum-gralnbd, chlorlte replaces b lo t l te , generally ser la te texture. Sane ample3 are dl8tlnctly blmodal wlth

e very flns-gralned mosalc i n l e r s t i t l a l t o larger blotl te/chlerl te, quartz, plegloclase, and K-feldspar grains.

306 82DB199A 56'31 '26" Petersburg Tag Blotl tc Granite--Fine- t o mealum-grained, lnequlgrenular. hypldlmorphlo granular, c.1.

132°04'31n C-1 04. Very alnor mount of accessory apatl te, opaques and sphene. Blotlte partly

altered to chlorlte, minor alteratlon or plagloolase. Core ample.

307 8ZKR071 A 5h032'55' Petersburg Tag Blot1 t e Granodlwlte--Pine- t o nedlra-walned, lnequlgranular , C.I. 04. Sllght b io t i te

1 32O06 I 02" C- 1 follat lon, ameuhat p l a g l o f l ~ e porphyrltlc. nlnor accessory opaquos. Mlnor plaglo-

olaae alteratlon.

308 ~52716 56'31 105n Poteraburs Tag Blotl te Cranlte (Amax rample--Age data only. Other Oeaeriptlve information and

1 33°03437* C-1 geochemical values not lncluded in t h l r report) .

(approx.)

Tgdb Granodlorlte of central Coast Metmwphic-Plutonic Complex, axpoamd adJacent t o the International Boundary. Sphene-

bearlng blotlte-hornblende ganodiorlte: nonfoliated, hanoaeneoua, medlw- t o ooarse-grained. Petrographic features

include zoned, rubhearal plagloclsae, myrmekl t e lntergrorths and chlwl tlzsd blot1 t e and hornblende.

309 81 DB215A 56'47 #25" Peteraburg Tgdb Blotl te Grrnlte--Coarse-grained. aer la te , lnaqulgranular , C. I. 04 wlth aoceasay

i 32°02v45m D-i magnetite. ~ l o t l t e has minor on lwi t e alteration. Piagloclase at~ous oxtenalve

serlclt lzetlon.

310 81SH066A 56°49*50" Peteraburg Tmdb Hwnblende-Blot1 t e Cranodlorl te--Foliated, medlm- to aoarsw-gralned, equlgrenular,

1 32'06' 32" D-1 C.I. 06. Blotlte and hornblende altered t o chlorite. Plagloclase cores altered to

4erlclte. Accessory lphene and magnetite. Outcrop l a hwogrneous.

31 1 81SK235A 56°50*16* Peteraburg TRab liwnblsnds-glotlte ~ranodlorlte--c.I . 08. mealum- t o coarse-grained. equlganular,

1 32°00'02" 0-1 wltn acoesaory uphene t o 5 am. Blotlte and hornblende altered t o chlorite, plagl0-

Claae shows some altsretion t o aerlcite. Outcrop 1s hanogeneoua.

312 81SK2113A 56°~8'27" Petwaburg TWb Hornblende-Blotlte Cranadlwlte--Foliated, medlun- t o ooarse-gained, epulmanular with

132°03'la" D-1 accessmy Dphene and magnetite, C.I. 08. ~ l o t i t a MO hornblende ahor alterallon to

ch lwl t e . Plrgloclase showa alteratlon t o r e r l c l t s . Outcrop l a homogeneous

31 3 81D8107A ' 56'57'28" Peteraburg Tgdb Hornblendo-Blotlte Cranodlorlte--Uedlum- t o coarse-aralned. lnoqulgranular , C. I. 15.

1 32°08135" D-1 Blotl te and hornblende show alteratlon t o chlorlte. P l a~ loc l a se I s stronaly zoned.

Aoceaaory aphene and magnetlte.

Table 2.--Petrographic descrlptiona or sample localltles--Contlnuad,

nap Sulple Latltude nap Nunber Umber Longltude Quadrangle Unit Sample descrlpt lon

TJ~J [rmodlwl to of the Central Conat Metmwphic-Plutonlc ocwplex--Exposed aouthuest of the Intarnatlonal Boundary. Por-

phyrltlc blotlte-hornblende pamdlo r l t e , ulth falnt marlc follat lon. Potraeaphic features Include hypldlmorphlc-

gronu1.r texture. auhedral t o aubhedrol K-feldspar phenocrysts t o 3.5 cm and ublqultow myrmeklte.

314 81OB2lOh 56'51 '17" PetaPSbWg Tgdp Blotlte Cranodlorlte--Sllghtl y To1 lated, coarse-gralnad, equlgranulu, K-spar t o 2 n.

1 32'07'25" 0-1 C.I. 10. w ~ t h acceasmy sphene and opaques. Plaploclasa l a aerlci tized and myrmeuitt.

l a abundant. Outcrop aut by mlnw blotlte-hwnblende granodlorlte dl kes, uhlcn are

looally achlleren, t o 10 rn thlck.

315 61RKZ\Oh 56O52'53" Petersbwg T ~ d p Hornblende-Biotlte Cranodlorlte--Slightly to l la t rd . medlum-walnad K-*par porphyry,

132'08'1 5" D-1 C.I. 15, wlth acoessory ophene and rpat l te . Biotlte and hornblende show alteratlon t o

chlorite. Plagloclase anous minor alteratlon t o rer lc i te . Outcrop cut by maflc,

f e l s l c , and p e p a t l t l c dlwas.

Ttos Intrurlve rocks or Coaat Plutonic Cauplex S i l l Belt located northeast of Coa3t Ranae megallnement--Biotite-nornblwnde - md hornblende-blotlte t ena l l t e , quartz d l w i t e and minor ganodlarl ta. Hmogeneo~. to l la ted , medlun- t o coarse-

gralned, locally hornblende porphyrltlc, c m o n lnclusloru ana rchlleren of d lor l t lc Oanposltlon. Texture varles from

equlgranular t o ror la te , po lk l l l t l c hornblende common and epldote minerals are rare.

316 78RH241A 56Ou3'30" Petersburg Ttos Blotl te Tonallte--Gnelsaoae texture, fo l l r ted , medlum-gralned. C.I. 16, ulth accessory

1 32Ol2'33" C-1 aphene and apati te. BlOtlte ahoua alteration t o chlorite. Plagloclaae has oommon

a l tera t lon t o ser lc l te md myrmeklte intergrouths.

317 78AFl41C 56°33'0?n Petersburg Ttm Hornblende-Blotlte Cranodiwlte--?oliatlon aeflned by mallcs, medlun-gralned, C.1. 25.

1 3 f 01 158n C-1 Feu hornblende phenocryats u ~ t h abundant inclusions. rccesswy apat l te , sphene, and

opaques. Mlnor b lo t i te al teratlon t o chlorlte.

BlDB1061 56°58'56n Peterabur8 Ttes Hornblende-Biotlte Gramdlorlte--Gneias05(1, medium-grained, lnequlgranular , with

1 32°12t08" D-1 accesaory aphene, C.I. 35. Hwnblenda and blo t l ta abw mlnor alteratlon t o

onlorlte. Plagloclase l a s l ight ly aerlcit lred. Outcrop out by blotl te apl l te velm.

31 9 t8D6137A 56031t55" P0tW8burg T t w Blotlte-Hwnblende Tonallte--Foliated, ooorae-grained, equlgranular, C.I. 24, with

1 32'00 ' 30" C- 1 accessory sphene, apatl te and opaques. Plagloclase hlgnly altered t o s e r l c l t a , mlnor

myrmeklte lntergrowths. Outcrop contain8 mlnor lncluslona or blotlte-hornblende

gnelss and And schlelren whlch we parallel t o t n b follet lon.

78D82118A 56O33'45" Peteraburg Ttoa Blotlte-Hwnblende Quartz Dlwite--Foliated. coarse-gralned, ser la te texture wlth

132'03 I 51 " C- 1 acce~aory aphene, apati te ma opnquel. Blotlte and hornblwnde snow rnlnor alteration

t o chlwl te .

82RK796A 56°35'46n Peteroburg Ttos Blot1 te-Hanblende Quartz Dlorl te--Slight to1 latlon of malics . Inequl granular, doml-

132001 '19" C-1 nantly coarse-gralned ulth aeriate phenocrysts of hornblende and plagloclase. C.1. 18,

Accessory sphene and opaques. Sane b io t i te al teratlon t o chlorlte, and s e r l ~ l t l ~ a t l ~ n .

60080721 56O35'08" Peterrburg Ttas Blotlte-Hwnblende Quartz Dlorlte--Foliated, medium-gralned, lnequlgranular, C.I. 29.

1 32'02 * 1 0" C- 1 ul th accessmy apatl ta, opaqutta end zlrcon. Hornblende and blo t l te lncer~rorn .

BODB242A 56°4811?w Peteraburg Ttoa Hornblende-Rlotlte Tonallte--Gnelsaoae texture, medlwgrrlned, hornblende porphyrltlc,

1 33°25'57" D-2 C.I. 26, rccessory spnene, epldote and zlrmn. Plagloclrse ohors a1 teratlon t o

aerici te.

82SK10lA 56O39'1 8" Peteraburg Ttoa Blotlte-Hornblende Tonal lta--Fol lat Ion defined by mar lcs , serlopnrphyrl t l c plagl oCla9e

13p09'59" C-1 and hornblende, lnequlgranular, C. 1. 22. Accessory opaque8 and aphene. Blotl te

unaltered: Mrnblende shows mlnor chlorlte al teratlon. nlnor achlleren,

. - 60

Table 2.--Petroeaphlo deaerlptlona of eample looalltlea--Continued.

- . . . - - Sample Lntltude nap Nmber Longitude Quadrangle Unlt Smple descrlptlon

BlSK239A 56'45'55" Petersburg Ttoa Blotlte-Hwnblende Tonalltle Gnelss--Umdlm-palned, follated, banded, C . I . 35. Out-

132°~6a17m D-1 erop o u t by minor p e ~ a t l t l e dlkes.

BlSK248A 56°44'28w Petersburg Ttoa Blotlte-Hornblende Quartz Dlbrlte--Pollatedi l n e q u l ~ ~ u l ~ ~ asdlun-grslned. C.I. 30.

1 3 ~ ~ 0 0 * 0 6 " C-1 Hornblende up t o 4 lorn. In length polkl l l t ica l ly molmer p l rg lo~laae md quartz. Blo-

t l t e l a ragged and cnlorltizsd. Sphene l a aeoondmryi magnetlte present.

81 DB253A 56°54110n Petersburg Ttor Blotltotlornblende Tonal1 t l o Cnelss--Foliated, llneated, lnequlgranular , serlopwphy-

1 32°30806" D-2 r l t l c hornblende, C.I. 28. Mlnor b lo t l te altmratlon t o ch lwl to and secondary

epldote. Scnlleren at outcrop scale.

81SK216A 56°j~t20w Peteraburg Ttol Blotlte-Hornblende Tonalite--Inequlgranular, hypidlmorphlc-gmular, aerloporphyrltic

1 3 P 0 8 ~ 2 5 ~ C- 1 hornblende, C.I. IS. Plagloolase has Mderate amount or sericlt ization. out-

crop I s hmogenctous and masslve.

82SK123A ~6'42139~ Petersburg Ttos Blotl te Tona l l tm- - lnepu l~anu lar , medlum- t o marae-Calned, llneated; C.I. 20.

132O18*08" C-1 Acceasay aphene, rpa t l t e and opaques. nyrmeklte in t t rgrowtb, feu plagloclane gralm

gralns hlghly aerlclt lzed. Crudely follated In outcrop.

81 SK236A 56°46*09" Petersburg Ttoa Blotl te-Hornblende tonali ts-Coarse-ralned, lnequl granular, C.I. 34. M d l O achlerm

132~16~17" D-1 with accesswy magnetite.

79RS203A 56°52'44" Peteraburg Ttos Hornblende-Blatlte Tonallte--Follrtad. hornblsnde porpllyrltlc, lnepulgranular, C.1. 20.

132O28' 43" D-2 Acceas~~y sphene, ragnetlte m d aeoondary epldote, nlnor amount of plagloclanm alter-

ation.

82DB195A 56°30*27n Petersburg ~ t o a ~lot l te -nornblmae tonal lte--well foliated, coarse-pralned, lnequigrmular, C.I. 30.

132000q44" C-1 Accessory sphene, opaque3 and apatite. L l t t l e Or no alteration of maflcs w plaglw

clase.

82KR066A 56'32'56" Peterbburg T t w Biotite-Hornblende Tonallte--Well to l la tea , hornblende porphyritic, inequlwanular,

1 32°03$09" C-1 C.1. 30. hcceaawy spheno, opaque3 and apatlte. Follatlan Oeflned by hornblende.

78RS092A ~ 6 ~ 3 3 ' 3 3 ~ Petersburg Ttos Blotl te-Hanblende Tonal its--Foliated, medl m-ooarae gralned, hornblende p rphyr l t l c ,

1 32003' 42- C- 1 C . I . 26, accesscry opaques. naflc minerals lntergroun; minor mount or onlorlte and

aphene a1 teratlon f r m blot1 te.

82SK122A 56°~0'32* Pmtersbur@ Ttoa Blotl tet lanblende Tonallte--Medium-gralned. lnequlpanulu , hornblende porphyrltlc,

132°08127n C-1 C.I. 25. Minor accessory apat l te and opaques. Myrmeklte lntergrouLh3 are wmmon;

alnerals appsar fresh. Hwnblsnds I s allgned but found In awlrls at outcrop scale.

BOSK609A 56°48'49" Pateraburg Ttos Blotlte-Hwnblmnde Tonallte--Slightly toliated, medlm-grained, C.1. 23. wlth acces-

13P22122" D-2 n a y zircon and magnetite.

TBRSO66A 56"49'27" Peteraburs T tw Hwnnlende-Gnel solo Tonal 1 te--Fol lated, meal un-era1 ned, C. I . 35, wlth acoeasory

132013'06" 0-1 sphene and magnetite. Hornblende cmon ly altered t o chlorite: plagloclase

hlghly ser ic l t lzed .

fntrualve roclts of Cou t Plutonic Cmplex $111 Belt, oxposed a t Thoma9 Bay and psnlbly r l on l the Stlklne RlVer,

Gnelrrlc b lo t l te ~ a m d l o r l t e and quartz monzodlorlte. Hanogeneolw, Tollated, local K-frldspar augen md K-feldspar

Phanocrysts t o 2.5 a. looally banded. Inequigranular texture, local dlssenlnatmd p r n e t , and local myrmekite.

7 9 ~ 8 2 2 5 ~ 56°5f1121m Petersnurg Tgag Hornblende bnd ~ i o t l t s - m a r i n g orthognelaa--~oliated, inequigranular, C. I . 1 B.

132°46n41n D-3 Cmpoaltlon 1s quartz monzoalwlte. Accesswy apnsne, apat i te end secondary ep1dot.e.

Euhedral chalcopyrlta md opaques. Felslc %re1 rw show camon s l i e r atlon, f ractur ing,

and myrrnekl t e Interwartha. >-,.

61

Tabla 2 . - -Pe t rop rph lc deso r lp t Ion3 of a m p l e loca l I t 1 es--Cont lnued.

- nap S w p l s La t i t ude flap

NmDer Nmbor Longltude Q w d r m g l e Uni t Sample d e s a r l p t l o n

TKba H e t m w p h l o rook$ of Coast Metworphlo-Plutonlo Ccmplex, exposed a long e a s t e r n r k r o r of Frederick Sound. B l o t l t c - s c h i s t , well f o l l a t e d and l l n e a t o d , f l n e - t o mealum-painea. Typlcal @reemohlyt mlneral aascnblages are garnet-quartz-

b l o t l t e - r l b l t e . Hlgher grade a s s m b l ~ g e s lnolude garnet-q~art~-bl~tlts-plagl wlM0, garnet-mtawol l t e -qua r t z -b lo t1 t e -

p l rg loo laae . Md ga rne t - a l l1 lmanlte-blotlte-plagloclue. Unl t .ay racord m u l t i p l e m o t v w p h l a eploodea.

339 8lSKl59A 5605q159" Peteraburg TKbs B io t l to-Quartz-Feldspar Gnelas--f Ine- t o very f lne -g r8 i nod, moderately uell-To1 l a t e a

132°49'22n D-3 o r thogne l s s . C.I. 5. O l l g o o l m e fo ldspa r l a m h e d r r l . q u a r t z l a a t r s l n e d and In

J t r l n g e r s , green-brwn b l o t l t o is poorly segregated. Accessory a p a t l t e , musmvlte .

and opaques. Sparse a e r l o l t e , o h l o r l t e , ep ldo te , and c a l c l t e .

340 82KRO68A ~ 6 ~ 3 2 ' 5 5 " Peternburg TKba Garnet-Hornblende Sohlst--Fine- t o medlm-gralned, moacrr te ly we l l - fo l l a t ed . CignLy 132%4101n C-1 percent hornblende; 5 peroent l a r g e garnet p o l k l l o b l a s t s l nc luae qua r t z . Quar t z

s t r l n g e r a w e p a r a l l e l t o the f o l l a t l o n i p l ag loc l a se is i n t e r s t l t l a l and a t r a l n e d .

Accessory b l o t l t e . magnet i te , and apa t l t e . n lnur c h l o r l t e f r m garnet . .- - - - - -

TKhs W t m w p h l o rooks of Coast Me twwphlc -P lu ton ic Cmplex exposed on e l t n e r o lde of t he Coast Range megallneament. - Hwnblenda d c h l s t and aemiachla t ; poorly- t o u s l l - f o l i a t e d , l o c a l l y l i n e a t e a In t e r l aye rea hornblende s c h l s t , s emlsen l s t ,

m d l e s s e r m o u n t s of b l o t l t o ~ c h l s t . Fine- t o mar se -g r r lned , t yp loa l mlneral n3semDlage l a quartz-garnet-hornalenao-

p l a g l o c l u e .

341 82KR071B ~ 6 ~ 3 2 ' 5 5 ~ Poteraburg TKM H W n D l m d ~ P lag loo l sae ~ n e l s s - - ~ e d l m - p e l n e d . poor t o maderate f o l l a t l o n , nma to - 1 32'06 02" C- 1 b l a s t l o . C.I . 25. Xenoblas t lc ho rnb lende~ o l igoo laae t o rndes lne f e l d s p a r ; stringers

and l e n s e s of qua r t z p re sen t . Other minerals a r e red-broun b l o t l t e , r p a t l t e , and

aparaa secondary Ch lo r l t e and aphene.

f a b l e 3.--P@tassiw-a-ga1? determinations i n the Petersburg ar.d par t s of the Pert L lexa~der and S s d m 1:250.000 qsad-a-gles.

southeastere Alaska.

(Argon analyses by A. Berry, S. Kollman, 8. Myers. J. Sa3uromacu, and J. vcr. Esser.: and potassi.& analyses by L. Es333.

p. Klock, L. Schlocker. and D. Vivi t )

Lat i tude Map F ie ld and Arrad_ :p r rad Age

PO

No. NO. Quadrangle Unit Longitude ROCK type Material ~ ~ 3 ' Moles/, Ar to ta l (na)

3. 7lABgl79A Petersburg QP 56'28'00" Basalt Vhole rock 0.511 2.006xl0-~ 0.03 0.269fp.087

B-4 1 3P08*40m o.51l: 0.511

0.520

(0.511)

4. 7lABgl78A Petersburg Qb 56°28'48* $malt 8-4 133O07'42~

7. 7lABg189A Pe te r sbwg Qb 56'26-50" Basal t 8-4 1 33O06'40"

25. 83SK467A Pe te r sbwg QTr ~ 6 ~ 3 3 ' 4 2 " ~ h y o l i t e C-5 1 3 3 ~ 2 7 ~ 4 4 "

Whole rock 0.577 2.325xl0-l3 0.m 0.279f0.065 0 . 5 3 0.575 0.579

(0.578)

Whole r o c k 0.461 2 .863~10"~ 0.01 4.15~6.95 0.521 0.P71 0. P6P

(0.479)

h o l e rock 5.66 1.675xl0-~O 0.36 20.420.6 5.67

48, 79DB027A PetePSbmg UTA 56°~7'01" Andesite whole rock 1.255 3.893~10"~ 0.86 21.59.6 C-6 133 41'25" 1.241

1.243 1.247

(1.248)

53. 83SK469A Pe te r sbwg QTm 56°2*27* Basalt Whole rook 1 . 2 1 ~ 3 . 7 3 3 ~ 1 0 - ~ ~ 0.73 21.29.6 C-5 133 24.52- 1.215

1.217 1.223

(1.217)

88. 80DB057A Pe te r sbwg tmae ~ 6 ~ 1 0 ' 1 3 " Biotite-hornblende Hornblmde 1.301 3.490x10"' 0.28 18.5+0.6 A-2 132°23*39" mmi t e 1.308

(1 .30~)

108. 79SHO59A Pe te r sbwg Tmge 56°05'34" Hornblende- B i o t i t e 7.48 2.173x10-~O 0.45 19.9'0.6 1-2 1 3 ~ ~ 2 5 ' 4 9 ~ Biotf t e Grani te 7.5fc

(7.525)

Hornblende 1.065 3.144~10-~' 0.51 20.3f0.6 7.57

(7.5231

109. 7M114 Pe te r sbwg Tmge 56O16'55" Miaro l i t i c B i o t i t e 6.017 0.009073 ppn 0.442 21.520.9 8-2 1 32°31'45" & m i t e 5.976 0.009Q12 ppm 0.31 9

(5.955) (0.0092~3)

110. 82DB260~ Petersburg Tme 56'03'1 6" Porphyri t ic B i o t i t e 8.01 2.254~10-~O 0.42 19 .39 .6 A- 1 132°07'04w B i o t i t e Granite 8.11

(6.09)

113. 8ZKR090A Petersburg Tme 56°04'39" Biotite-Hornblende Hornblende 2.22; 6 . 9 5 8 ~ 1 0 - ~ ~ 0.42 21.49.6 A-1 132°1~'46w Quartz 2.257

noctodiorl t e (2.2t:)

149. 8ORS051A Port Alex- TmgK 56°42141w Horflblende- ~ i o t l te 6.76 2 . 3 3 8 ~ 1 0 - ' ~ 0.35 23.5'0.7 ander C-1 134~18'52' B i o t i t e Granite 6.93

(6 .E :

151. 8ZSH053A Por t Alex- T ~ d k 56°~1m08* Biotite-Hornblende Hornblende 1.026 2 .930~10-~ 0.31 1 9 . 5 ~ 0 . 6 ander C- 1 134°18'~2n Quartz Dior- te A 1.043

(1.Cj6;

Table 3.--Potassim-wgon determinations in the Petersburg and parts of the Po?: Alexander and S m 3 m 't;230.000 quad-ar.~!es,

aa~%heasterr! Alaska--(Continued)

Latitude ,. - ,. - nsp Field and quArrad "Ar Age No. NO. Quadrangle Unit Longitude Rock type Material K ~ O * n o l e s / p u ~ ~ r r a d t o t a l (Ma'

. . 158. 79DB108A Petersbwg Kvgo 56O12'36" Biotite-hornblende Hornblende 0.526 8.000xl0-" 0.60 100.0-3.0

A-5 1 33°26'38" Granodiori t e 0.554

167. 79DB097A Peternburg Kwqa 56°05'59w Bictlte-Hornblende Bioti te I . 53 1.204xl0-~ 0.91 108.013.5 A-5 1 33°29'20" Uranodiorite 7.55

(7.5'1)

Hornblende 0.372 5.425110~ 0.72 98.7'3.0 0.371

(0.371 5)

170. 82SH055A Port Alex- Kwpo 56°08q07n Biotite-Hornblende Bioti te 8. 03 1.3114~10-~ 0.82 112.023.U ander A-1 1 3h009*05* Cranoaiorite 8.07

(8.05)

212. 78RSlpA Peteraburg Ktef 56°15'45w FoliatedTonali ts Bioti te 9.41 1 . 5 6 ~ 1 0 " ~ 0.89 83.2~2.5 0-2 1 32'20'33" 9. b4

(9.425)

Hornblende 1.155 1.569~10-~O 0.80 91.6~2.7 1.163

(1.159)

211. 78DB113 Petersbwg Ktef 56O 1'51" Porphyritic Garnet- Biot i te 9.27 1.099%10*~ 0.77 79.9~2.4 C- 1 13$19'12" Hornblende-Biotite 9.42

Quartz Diorite (9.3455)

Hwnblcnde 1.102 1 . ~ S S X I O - ' ~ 0.77 88,6+2.7 1.125

(1.114)

225. 78BG030A Petersburg Ktif 56°22'56w Biotite-hornblende Biot i te 8.99 l,200*10-~ b.53 90.45.7 8-2 132O38'53" panodier i te 8.99

(8.99)

Hwnblende 1.368 1.844~10-~' 0.88 93.0+2.5 1.375

( 1.372)

228. 79081 92A Petersburg Ktif 56°$9'30" Hwnblendebioti to Bioti te 9-54 1.264xl0-~ 0.92 89.622.7 C-3 132 45'16" quartz d i w i t e 9.58

(9.56)

Hornblende

239. 82KR096A Petersbwg Ktop ~ 6 ~ 0 0 ' 4 7 " Porphyritic horn- Bioti te A-1 132~03'22" b lendebio t i te

quartz d ior i te

254. 78RM25hA Peteraburg Kqop 56°46'08w Hornblende-Biotite Biot i te D-4 13P13 '47~ Tonalite

Hornblende

259. 82PB023A Petersburg Kqop ~ 6 ~ 4 2 ' 5 5 ~ Porphyritic Bioti te Bioti te C-3 133O01 '45" H~rnblende Quartz

Diorite

Hornblende

267. 8ORS145A Petersburg Kpo 56'5~~38" Foliated Porphyritic Biot i te D-4 133°01'1 2" Biotite-Hcrcblende

D i o r ~ t e

Hornblende

Table 3.--Potusim-arpn determinations in tM Peteraburg and parts of the Port Alexa?der k?d Sumdm 1:250.000 q u a d r m ~ l e s .

sou'heatern Alaska-- (Contir.ue6).

Latitude . - b - Map ~ i u l d and Arrad 4UArrad ~ g e

9u

No. No. Quadrangle Unit Longitude Rock type Hater i a1 K,O* Moles/@ "Artntll (Y.1

305. A33125 Petersburg T 56°~0'35" Rhyolite Mrumvite 5.577 0.006028 ppm 0.302 15.OfO.6 C- 1 132 03'10" Porphyry 5.354 0.00571P ppm 0.285

(5.465) (0.005871)

308. A52716 Petersbwg Tag 56°j1'05" Bioti te Bioti te 6.984 0.008305 p p 0.293 16,3=0.6 C- 1 132 03'37" Cranlte 7.041 0.008047 ppm 0.507

(7.012) (0.008176)

313. 81DBlO7A Petersburg ~ g d b ~ 6 ~ 5 7 ' 2 8 ~ Biotitt-tlornblende ~ i o t i t e 9.10 6.832~10- '~ 0.65 51.321.5 D-1 1 ~ ~ 0 8 ~ 3 5 ~ Csmdio r i t e 9.1 P

(9.12)

Hornblende 1 .I20 8,078x10-~~ 0.74 49.321.5 1.126

(1.123)

31 4. 81DB210A Pstersburg TgPp 56'51 '17" Bioti te hornblende Bioti te 8.82 6.639x10-~~ 0.69 51.2y.5 0- 1 132°07v25* r a n o d i w i te 8.94

(B.88)

331. 79RS203A Petcrsburg T t a 56°52144w Foliated Porphyritic Bioti te 8.77 6.573~10-'~ 0.40 51.2.1.5 D-2 132°28*43n Biotiteturnblende 8.81

Quartz Diorite (8.79)

Uwnblende 0.978 7.357x10-" 0.26 51.621.5 0.975

(0.9765)

334. 7BRS092A Petersburg Ttoa 5 6 ° ~ 3 v 3 ~ " Foliated Pwphyri- Bioti te 9.24 6 . 8 1 2 ~ 1 0 - ~ ~ 0.84 50.4y.5 C- 1 132 02'42" t i c Tenalfte 9.29

(9.265)

Hornblende 1.130 8,126~ro-'' 0.45 49.1:l.s 1.136

(1,133)

References c i t e d

Brew, D.A., Ovenshine, A.T., Karl, S.M., and Hunt, S.J., 1984, Preliminary reconnaissance geologic map of the Petersburg and parts of the Port Alexander and Sumdun 1 :250,000 quadranglee, southeastern Alaska: U .S. Geological Survey Open-File Report 84-405, 43 p., 2 sheets.

Buddington, A.F., and Fairchild, J.G., 1932, Some Eocene volcanica in southeastern Alaska: American Journal of Science, v. 23, no. 138, p. 490- 496.

Crass, Whitman, id ding^, J . P . , Pirsson, L.V., and Washington, H.S. , 1902, A quantitative chemico-mineralogical clasaif ication and nomenclature of igneous rocka: Journal of Geology, v . 10, p . 555-690.

Muffler, L. J.P., Short, J.M., Keith, T.E.C., and Smith, V.C. , 1969, Chemistry of fresh and al tered basal t ic g l a ~ s from t h e upper Triassic Hound Island Volcanics, southeastern Alaska: American Journal of Science, v. 267, p. 196-209.

Shapiro, Leonard, 1975, Rapid analysis of s i l i c a t e , carbonate, and phosphate rocks--revised edition: U.S. Geological Survey Bulletin 1401, 76 p.

Steiger, R.H., and Jager, E., 1977, Subcommi~zion on geochronology: Convention on the use of decay constants in geo- and cosmochronology: Earth and Planetary Science Letters, v. 36, p. 359-362.

Streckeiaen, A. L. , and others, 1973, Plutonic rocka: Classification and nomenclature recommended by the IUGS ~ubcommi~ai on on the systematics of igneous rocks: Geotimea, v. 18, no. 10, p. 26-30.

Taggart, J .E . , Jr., Lindsay, J.R., Scott , B.A., Vivit, D.V., Bartel, A . J . , and Stewart, K .C., 1987, Analysis of geologic materials by wavelength- dispersive x-ray fluorescence spectrometry, 9 Baedecker, P.A., ed . , Methods for geochemical analysis: U. S. Geological Survey Bulletin 1770, p. E l - E 1 9 .

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Susan H. - dggs.alaska.govdggs.alaska.gov/webpubs/usgs/of/text/of89-0527.pdf · UNITED STATES DEPARTMENT OF INTERIOR GEoL0eK;ALsURVEY Major-element chemistry, radiometric ages, and