Deep Sea Drilling Project Initial Reports Volume 67 · DEEP SEA DRILLING PROJECT LEG 671 ... and rare Creta-ceous and Eocene forms in Cores 28 and 29. ... assemblage on the strewn

11. RADIOLARIANS FROM THE MIDDLE AMERICA TRENCH OFF GUATEMALA,DEEP SEA DRILLING PROJECT LEG 671

M. J. Westberg and W. R. Riedel, Geological Research Division, Scripps Institution of Oceanography,University of California, San Diego, La Jolla, California

ABSTRACT

Radiolarians were found at all Leg 67 sites. At oceanic reference Site 495 and Trench floor Sites 499 and 500, radio-larian sequences from the lower Miocene Stichocorys delmontensis Zone through the Quaternary were recovered. Foursites were located on the inner Trench slope: at Sites 496 and 498, drilling penetrated to the Calocycletta costata Zone ofthe early Miocene, at Site 497 only Quaternary and Pliocene material was recovered, and at Site 494, the Cretaceous wasreached. An index of reliability is described and used to resolve conflicts in radiolarian correlations of the seven sites.The composition of assemblages is described in terms of relative abundances of radiolarian families, and these data areused as a basis for comparing margin and open-ocean sites.

INTRODUCTION

Radiolarians were recovered at all seven Leg 67 siteslocated on a transect of the Middle America Trench offGuatemala. Oceanic reference Site 495 is on the CocosPlate, 22 km seaward of the Trench axis; Sites 499 and500 are on the Trench floor; and Sites 494, 496, 497, and498 are on the inner Trench wall. The localities andwater depths of the sites are:

Site 494, 12°43.01'N, 90°55.97'W, 5529 metersSite 495, 12°29.78'N, 91°02.26'W, 4150 metersSite 496, 13°O3.82'N, 90°47.71'W, 2064 metersSite 497, 12°59.23'N, 90°49.68'W, 2358 metersSite 498, 12°42.68'N, 90°54.94'W, 5497 metersSite 499, 12°40.23'N, 90°56.65'W, 6127 metersSite 500, 12°41.16'N, 90°56.58'W, 6127 metersRadiolarian assemblages range from lower Miocene

to Quaternary at Sites 495, 496, 498, 499, and 500 andfrom Pliocene to Quaternary at Site 497. Site 494 con-tains a Pliocene to Quaternary sequence from Cores 1 to20, rare lower Miocene forms in Cores 20 to 22, a mid-dle Eocene assemblage in Cores 23 to 27, and rare Creta-ceous and Eocene forms in Cores 28 and 29. Figure 1 isa synopsis of radiolarian zones represented in Leg 67sites.

In many of the Quaternary and Pliocene samples,and in Miocene slope sediments, radiolarian assem-blages are diluted by clay aggregates, ash, diatoms, orterrigenous minerals.

PROCEDURESGenerally, we took two or three samples per core, but rapidly ac-

cumulated sediments were sampled at longer intervals. Sediments weresieved at 44 µm and strewn slides prepared in our standard manner.

Relative abundances of species are recorded in two ways. First, inthe main part of ranges and at most morphotypic limits, five grades ofabundance indicate the percentage that a taxon represents of the totalassemblage on the strewn slide. These abundance grades are explained

Aubouin, J., von Huene, R., et al., Init. Repts. DSDP, 67: Washington (U.S. Govt.Printing Office).

in the note to Table 1. Second, near evolutionary transitions, "con-stant-numerator" percentage estimates were used. The density of ra-diolarians on a slide having been estimated, this density is then used toestimate the number of radiolarians in a counted number of fields thatmust be searched to find 10 specimens of a taxon (Riedel and San-filippo, 1978a).

Relative abundance data for radiolarian families are recorded in athird way. At least 300 radiolarians per slide were categorized in 15families, and percentages calculated and rounded to the nearest wholenumber. The family abundance tables also include an estimate of theproportion of each field covered by diluting components such as dia-toms, volcanic ash, or terrigenous debris.

The radiolarian zones used in this paper for the Tertiary are thechronozones defined by Riedel and Sanfilippo (1978b). The Quater-nary zones are those defined by Nigrini (1971).

SITE 494

Site 494 was drilled on a small terrace of the lowerTrench slope. The Holocene to Pliocene, dark gray, dia-tomaceous mud of Cores 494-1 through 494A-20 con-tains radiolarian assemblages of moderate preservation,but often highly diluted by clay aggregates, diatoms, orash. Because of the sparseness of the fauna and missingindex species, the Quaternary zones cannot be deter-mined. The latest occurrence of Axoprunum angelinumis between Samples 494A-2-6, 29-31 cm and 494A-4-1,1-3 cm. According to Hays et al. {Stylatractus sp., 1969)and Johnson and Knoll (1975), this species became ex-tinct about 320,000 to 400,000 years ago. The top of theSpongaster pentas Zone, indicated by the morphotypictop of Stichocorys peregrina, is between Samples 494A-17-2, 64-66 cm and 494A-18-1, 90-92 cm. Blue clastswith middle Miocene species occur throughout the sec-tion. Occasionally, Eocene species are reworked intothese younger sediments. Relative abundances of Plio-cene and younger taxa found in these cores are recordedin Table 1.

The blue gray hemipelagic clays of Sections 494A-20-4 to 494A-22-3 contain radiolarians in two differentpreservational states. There are moderately well-pre-served specimens of Calocycletta virginis, Eucyrtidiumdiaphanes, Stichocorys delmontensis, Theocorys spon-

401

M. J. WESTBERG, W. R. RIEDEL

Epoch

Qua

tern

ary

Plio

cene

late

Mio

cene

mid

dle

Mio

cene

earl

y M

ioce

ne

Oligo-cene

Eocene

Creta-ceous

Radiolarian Zone

C. tuberosa

A. ypsilon

A. angulare

P. prismatium

S. pentas

S. peregrina

D. penultima

D. antepenultima

D. petterssoni

D. alata

C. costata

S. wolffii

S. delmontensis

C. tetrapera

L. elongate

P. mitra

495

3-13-6

4-17-1

7-39-3

9-615-5

16-216-6

17-117-6

18-219-6

20-123-6

24-129-5

30-132-2

32-537-3

499

2-2

3-4

17-5

18-119-3

19-622-6

23-1 &B1,CC

23-123,CCB1 CC24-125-3B1.CC25-4 &B3-4

B4-1B6-1

5 0 0

1-110-2A1,CCA2,CC

10-210-3

11-311-4

12-3

13-314-4

498

1-11-32-1

A2,CCA3,CC

7A8-7?A9,CC

A7-17A12-1

A7-4

A10-17A13-1A15-2

Gas

494

1-14-4&A MA17-2

A18-1A20-3

A20-4A22-3

A23-1A27-2

A28-1A29-2

497

1-3

2-313-4

15-418-5

19-225-4

26-342-7

Gas

496

1-1

1-521-6

22-423-6

24-326-4

27-428-3

28-428-5

29-3

30-2

35-240-1

Gas

Figure 1. Radiolarian zones represented in Leg 67 sites. (Sites are ordered from westto east. Cores and sections from each hole are shown.)

goconus, and Cαrpocαnopsis cingulαtα. Occurring withthese are poorly preserved, probably calcitized speci-mens of C. virginis, Artophormis grαcilis, and Theo-cyrtis αnnosα. These latter could be reworked from thelate Oligocene or early Miocene. Samples 494A-22-3,91-93 cm and 102-104 cm contain none of the alteredforms, but have an assemblage made up largely of frag-mented spongodiscids with rare occurrences of Sticho-corys wolffii, S. peregrina, and Phormostichoartus cor-bula.

Dark gray mudstones in Cores 494A-23 through 494A-27 contain rare to common middle Eocene radiolarians,poorly preserved due to dissolution and fragmentation.The assemblage is probably from the Podocyrtis mitraZone, and includes Lithocyclia ocellus, Calocyclas his-pida, Eusyringium fistuligerum, Lithochytris vesperti-lio, Sethochytris triconiscus, Theocotyle cryptocephala,Thyrsocyrtis {Thyrsocyrtis) rhizodon, T. (Pentalocorys)triacantha, Podocyrtis papa I is, P. mitra, Dictyoproraamphora, D. mongolfieri, and D. urceolus.

The mudstones of Cores 494A-28 and 494A-29 con-tain both Eocene and Cretaceous forms. The dark olivegray sediment of Sample 494A-29-1, 14-16 cm includes

many of the Eocene forms just listed. The light graymud of Sample 494-29-1, 100-102 cm contains com-mon, poorly preserved, altered radiolarians deposited inthe Late Cretaceous: Amphipyndax stocki, Dictyomitrakoslovae, Dictyomitra spp., Eucyrtis micropora, andAlievium superbum. Very rare occurrences of the Eo-cene species Dictyoprora mongolfieri and Lophocyrtisbiaurita are from small dark chips of Eocene mudstonemixed by the drilling operation into the lighter Creta-ceous sediments. Sample 494A-29-1, 135-137 cm con-tains several fragments of what appear to be the Eocenegenus Podocyrtis, and rare, very poorly preserved Up-per Cretaceous Dictyomitra spp. Sample 494A-29-2,30-32 cm repeats this same mixture of predominantlyUpper Cretaceous radiolarians with a minor componentof Eocene forms.

No radiolarians were found below Core 494A-29.

SITE 495

Site 495 was drilled for an oceanic reference site onthe oceanic crust seaward of the Trench axis. Tertiarymovements of the Cocos Plate apparently caused thetransitions from early Miocene carbonate-rich sedi-

402

RADIOLARIANS FROM THE MIDDLE AMERICA TRENCH

Table 1. Abundances of some radiolarians at Site 494.E

po

chs

>

<o

σ

V/λ

Y//λ

VÁv/λi

<u<uuo

Zones

yyyyyyyyyy/vyyyyyyy///

yyyyyyyyy/'yyyyyyyyyhyyyyy//y///

/yyyyyyy////yyyyyyyyys>'yyyyyyyy//'

(Vf/f/fY///

v//0/Zv///

S. pentas

Hole 494 andHole 494A

(core-section,interval in cm)

1-1,

1-2,

1-4,

1-5,

1-6,

2-2,

2-3,

2-5,

2-6,

3-2,

3-5,

4-2,

4-4,

A l - 2 ,

A2-6,

A4-1,

A5-1,

A5-2,

A7-3,

A8-1,

A9-1,

A10-1,

A l l - 1 ,

A14-3,

A16-1,

A17-2,

A18-1,

A18-4,

A19-1,

A20-2

A20-3,

32-34

32-34

58-60

59-61

59-61

32-34

32-34

32-34

32-34

32-34

32-34

32-34

32-34

28-30

29-31

1-3

60-62

60-62

60-62

70-72

22-24

133-135

70-72

12-14

89-91

64-66

90-92

64-66

7-8

110-112

76-78

ide)

Ra

dio

lari

an

De

nsi

ty

(th

ou

san

ds

per

s

2.5

0.3

1.2

1.2

1.2

1.2

2.5

0.3

6.2

2.5

6.2

2.5

6.2

6.2

2.5

6.2

2.5

0.2

2.5

6.2

2,5

0.3

0.3

6.2

2.5

0.3

2.5

0.3

0.3

6 2

2.5

Pre

serv

ati

on

(p

oo

r, m

od

era

te,

go

od

)M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

MP

MM

M

M

M

MM

M

M

M

M

Mp

P

Bu

ccin

osp

ha

era

in

vag

ina

ta

-

-

-

-

-

Co

llosp

ha

era

tu

be

rosa

r

-

-

+

-

-

-

So

len

osp

ha

era

om

nit

ub

us

-

-

-

Axo

pru

nu

m a

ng

elin

um

-

-

-

-

-

-

-

-

-

-

-

-

-

_

R

r

R

r

R

R

F

F

r

-

R

R

R

R

R

Did

ymo

cyr

tis

avi

ta

-

-

-

Did

ymo

cyr

tis

pe

nu

ltim

a

-

-

Did

ymo

cyr

tis

tetr

ath

ala

mu

s

R

R

F

R

F

F

F

F

F

F

R

F

R

R

R

R

r

-

r

-

-

-

-

r

-

-

R

R

-

r

Am

ph

irh

op

alu

m

ypsi

lon

r

R

R

r

r

-

R

-

R

R

R

R

F

F

F

R

- .

-

-

-

R

-

-

-

-

-

-

R

-

-

Sp

on

gas

ter

be

rmin

gh

am

i

-

-

-

Sp

on

gas

ter

pe

nta

s

-

-

-

-

-

.60

.10

.30

.30

OS

.30

Sp

on

gas

ter

tetr

as

R

-

-

-

R

-

-

-

R

-

-

R

rr

r

r

r

r

r

r

r

R

F

r

.40

1.7

.20

-

.30

.04

Sp

on

go

dis

cus

am

bu

s

-

Lyc

hn

od

icty

um

au

da

x

-

Pte

roc

an

ium

p

rism

ati

um

-

-

-

-

-

-

-

-

-

-

-

-

-

-

_

-

-

-

-

-

-

-

-

-

-

-

-

-

Sti

ch

oc

ory

s p

ere

gri

na

r!

rl

-

-

-

-

-

-

-

-

r

r

D

R

An

tho

cy

rtid

ium

an

gu

iare

-

-

-

-

-

-

-

-

-

-

-

-

-

-

_

-

-

-

-

-

-

-

-

-

-

-

-

-

Ca

loc

ycle

tta

ro

bu

sta

gro

up

-

Lam

pro

cyr

tis

he

tero

po

ros

-

-

-

-

-

-

-

-

-

-

-

-

-

-

_

-

-

-

-

-

-

-

-

-

-

-

-

La

mp

roc

yrti

s n

eo

he

tero

po

ros

-

-

-

-

-

-

-

-

-

-

-

-

-

-

_

-

-

-

-

-

-

-

-

-

-

-

-

Lam

pro

cyr

tis

nig

rin

iae

F

R

F

R

R

R

F

R

R

F

F

r

R

r

R

R

r

r

-

r

-

-

r

-

-

-

r

Th

eo

co

ryth

ium

tr

ac

he

lium

F

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

r

Th

eo

co

ryth

ium

ve

tulu

m

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Ph

orm

ost

ich

oa

rtu

s c

orb

ula

R

R

F

F

R

F

F

R

R

R

F

F

F

F

R

R

R

R

F

F

R

R

R

R

R

R

R

R

R

R

Ph

orm

ost

ich

oa

rtu

s d

olio

lum

-

-

Ph

orm

ost

ich

oa

rtu

s fi

stu

la

-

-

Sp

iro

cyr

tis

gyr

osc

ala

ris

r

R

-

-

-

r

-

-

-

-

r

r

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Sp

iro

cyr

tis

scai

aris

r

-

r

R

-

r

r

r

-

-

-

-

-

_

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Note: In the body of the table — indicates that the species was sought but not found; + indicates < 0.01% of the radiolarians on the slide; r, very rare, 0.01-0.1%,R, rare, 0.1 — 1%; F, few, 1 — 10%; ! indicates reworking; < and > are used to indicate the dominant ta×on when an ancestors and descendants abundance falls inthe same percentage range. At critical parts of ranges, numbers indicate abundances in percentage of total radiolarians on the slide as determined by constant num-erator counts (see text).

ments with high accumulation rates to middle Mioceneradiolarian-rich red clays to hemipelagic muds of thePliocene and Pleistocene.

The first 37 of 49 cores drilled contain typical low-latitude radiolarian assemblages. The upper 171 meters,Cores 495-1 through -18, are a hemipelagic, green andolive gray mud. Assemblages are occasionally diluted by

terrigenous components or diatoms, but for the mostpart, radiolarians are common and well to moderatelywell preserved.

Species indicative of the upper two Quaternary zonesare absent at Site 495, and the first samples containAxoprunum angelinum, indicating an age of at least320,000 to 400,000 years. Gore 495-3 is placed in the

403


Amphirhopalum ypsilon Zone by the absence of Antho-cyrtidium angulare. Very rare occurrences of A. angu-lare in Cores 495-4 through -6 indicate the lowest Qua-ternary A. angulare Zone. The Pliocene/Pleistoceneboundary, and the top of the Pterocanium prismatiumZone, is placed between Samples 495-7-1, 70-72 cm and495-7-3, 70-72 cm by the latest occurrence of P. pris-matium. This designation, however, is tenuous becauseof the extreme rarity of P. prismatium and A. angulare.

The latest occurrence of Stichocorys peregrina be-tween Samples 495-9-3, 75-77 cm and 495-9-6, 26-28 cmmarks the bottom of the P. prismatium Zone.

The events indicating the bottoms of the Spongasterpentas and Stichocorys peregrina Zones, namely theevolutionary transitions between Spongaster berming-hami and S. pentas and between Stichocorys delmont-ensis and S. peregrina, respectively, occur in the sameinterval between Samples 495-16-2, 30-32 cm and 495-15-5, 30-32 cm, suggesting that the S. peregrina Zone iscompressed and not sampled. This conclusion is sup-ported by the latest occurrence of the Calocycletta ro-busta group in that same interval, an event known to oc-cur in the S. peregrina Zone.

The bottom of the Didymocyrtis penultima Zone isindicated by the latest occurrence of Diartus hughesibetween Samples 495-16-6, 30-32 cm and 495-17-1, 30-32 cm. The Didymocyrtis antepenultima Zone extendsfrom that interval down to the transition of Diartus pet-terssoni to D. hughesi between Samples 495-18-2, 90-92cm and 495-17-6, 30-32 cm. Relative abundances of lateMiocene to Quaternary radiolarians at Site 495 are re-corded in Table 2.

The muds of Core 495-18 and the carbonate-poor redclay of Core 495-19 belong to the middle Miocene D.petterssoni Zone. The earliest occurrence of D. petters-soni marks the bottom of this zone, between Samples495-19-6, 8-10 cm and 495-20-1, 60-62 cm.

Cores 495-20 through -37 are chalky carbonate oozewith chert in the lower section, and they continue a com-plete record of middle and lower Miocene radiolarianzones. The transition of Dorcadospyris dentata to D.alata, between Samples 495-23-6, 40-42 cm and 495-24-1, 15-17 cm, indicates the bottom of the D. alata Zone.The earliest occurrence of Calocycletta costata, betweenSamples 495-29-5, 19-21 cm and 495-30-1, 30-32 cm,marks the bottom of the C. costata Zone. The morpho-typic bottom of Stichocorys wolffii marks the bottomof the S. wolffii Zone, between Samples 495-32-2, 39-41 cm and 495-32-5, 39-41 cm. The remaining coresthrough 495-37-3 belong to the Stichocorys delmont-ensis Zone. Unusually low occurrences of Lithoperarenzae, S. wolfii, Phormostichoartus corbula, and Si-phostichoartus corona in abundances of < 0.1 °7o suggestdownworking between Cores 495-26 through -36. Sam-ples taken from Cores 495-38 through -43 and -46 wereall barren of radiolarians. Table 3 records abundancesof early to middle Miocene radiolarians at Site 495.

SITE 496At midslope Site 496, the objective was to penetrate a

landward-dipping seismic reflector, but drilling was ter-

minated short of this goal because of recovery of gase-ous hydrocarbons. The upper 226 meters of Hole 496are biogenic mud, but the well-preserved Quaternary ra-diolarians are diluted by 50 to 90% terrigenous debris inthe sand-size fraction.

Sample 496-1-1, 50-52 cm is assigned to the Collo-sphaera tuberosa Zone on the basis of the presence ofthat species. Between Sections 496-1-5 and 496-21-6,radiolarian assemblages belong to the Amphirhopalumypsilon Zone. Samples 496-22-4, 65-67 cm and 496-23-6, 32-34 cm are assigned to the Anthocyrtidium angu-lare Zone on the basis of very rare occurrences of A. an-gulare. The top of the Spongaster pentas Zone is placedbetween Samples 496-27-1, 70-72 cm and 496-27-4,29-31 cm by the latest occurrence of Stichocorys pere-grina. All of these zonal assignments are tenuous be-cause of the very low numbers of index species. Relativeabundances of Quaternary and Pliocene radiolarians atSite 496 are recorded in Table 4.

Samples 496-28-4, 87-89 cm and 496-28-5, 140-142cm are assigned to the 5. peregrina Zone because S. del-montensis is present, but in smaller numbers than S.peregrina. The upper Miocene Didymocyrtis penultimaand D. antepenultima Zones were not observed at thissite.

Samples 496-29-1, 90-92 cm and 496-29-3, 40-42 cmbelong to the middle Miocene Diartus petterssoni Zone.The Dorcadospyris alata Zone is indicated in Sample496-30-2, 45-47 cm by the presence of D. alata withoutD. dentata. Equal numbers of those two species in Core31, and their absence from samples from Cores 33 and34, prevent zonal assignments. However, all the samplestaken between Sections 496-35-2 and 496-40-1 appearto be in the Calocycletta costata Zone. Relative abun-dances of middle Miocene radiolarians at Site 496 arerecorded in Table 5.

SITE 497Site 497 was drilled on the midslope 8 km seaward of

Site 496 and was also terminated early because of re-covery of gaseous hydrocarbons. The sediments are pre-dominantly dark olive gray muds containing moderatelywell-preserved Quaternary to Pliocene radiolarian as-semblages highly diluted with terrigenous components.Relative abundances of radiolarians and zonations areshown in Table 6.

SITE 498Site 498 was drilled 1 km east of Site 494 on the lower

slope to avoid a transverse fault and improve corerecovery. Again, the hole was abandoned because of gasrecovery. Most of the poorly recovered cores are drillingbreccia composed of dark olive gray mudstone, withchips of blue gray Miocene mudstone. Many of the sam-ples from Site 498 yielded too few radiolarians for strati-graphic interpretation. Reworking of Miocene and some-times Eocene species into younger sediments is frequentthroughout the entire section.

Samples 498-1-1, 28-30 cm, 498-1-3, 128-130 cm,498-2-1, 30-32 cm, 498A-2,CC (14-16 cm), and 498A-3,CC (25-27 cm) contain Quaternary radiolarians. The

404


Table 2. Late Miocene to Quaternary radiolarians at Site 495.

Zones

Site 495

(core section,interval in cm)

c S £ •So ε S S

.5 ^

I Ilia ε 1 8 I i 1

1118 S S

3 S

i i

I ! 11 ! !oo ^ O

i, S

A. ypsilon

2 "watercore"

3-1, 1-3

3-3, 60-62

3-6, >O-22

4-1, 75-77

6.3

2.5

12.6

12.6

6.3 .005

- R- R

- R

- F

A. angulare

4-3, 75-77

4-5, 75-77

5-2, 40-42

5-5, 40-42

5,CC

6 . 3

6 . 3

2 . 5

6 . 3

1.3

.04

.03

.02

- .01

- .03

- .03

.63 .08 .01 F

.50 .04.01 F

,03 .16.03

.13 .06.59 R

6-1, 92-94

6-4, 10-12

6,CC 3-4

7-1, 70-72

7-3, 70-72

1.3

12.6

2.5

12.6

12.6

.008

.16

.03

.05

.04 - -

.008 .07.03

. 0 3 - 1.7

.006 - F R

- F

+ F R

- R

P. prismatium

7-4, 55-57

7,CC, 55-57

8-1, 16-18

9-3, 75-77

9-6, 26-28

12.6

12.6

12.6

12.6

6.3

F F

R

R F

R

+ F

10-4, 30-32

10-6, 30-32

10.CC

11-1, 60-62

11-3, 60-62

18.8

18.8

18.8

13.3

12.6

R>r

R r

< rR

R

R R

F -

R -

S. pentas

{S. peregrins

Zone probablymissing)

ll,CC,4-6

12-1, 80-82

12-3, 30-32

12-5, 31-33

12-7, 31-33

12.6

13.8

12.6

- .001!

- .06

.02 .08

R r

R F

R R

R

R R

13-5, 54-55

14-1, 30-32

14-3, 30-32

14-5, 30-32

15-1, 30-32

12.6

18.8

12.6

18.8

2.0

.02 .008

.03

.03

.04 .005

.30 .05 R .15

R R

R R

R R

F

R R

D. penultima

15-3, 30-32

15-5, 30-32

16-2, 30-32

16-4, 30-32

16-6, 30-32

18.8

18.8

18.8

18.8

18.8

1.6

0.8

0.9

.005

.005

.07

.02

.05

- r 1 . 0 2 1 . 0 2

+ r 1 . 5 1 . 5

- r 5 . 0 1 . 1

3 . 3 . 1

- + F r

r r

r +

r r

r -

r - -

r - -

R -

R r

R +

R -

r -

r

D. antepenultima

17-1, 30-32

17-2, 30-32

17-3, 29-31

17-4, 30-32

17-5, 30-32

17-6, 30-32

18.8

18.8

18.8

25.2

18.8

18.8

r F

F

F

r F

1.2

1.3

1.3

1.9

1.3

1.5

r

R R

R R

Note: Symbols as for Table 1.

first two samples are from the uppermost Quaternary, onthe basis of the presence of Buccinosphaera invaginataand Collosphaera tuberosa; and the remaining three areprobably older than 320,000 yrs., based on the presenceof Axoprunum angelinum. Sample 498A-5-1, 80-82 cmcontains about 500 specimens from the middle MioceneDiartuspetterssoni and Dorcadospyris alata Zones. Sam-

ple 498A-5-6, 135-137 cm contains a sparse assemblagefrom the Calocycletta costata Zone.

Radiolarians from Sample 498A-7-1, 40-42 cm,though sparse and poorly preserved, appear to be young-er, probably from the upper Miocene Stichocorys pere-grina Zone. Very rare specimens from the D. petterssoniZone were found in Sample 498A-7-4, 30-32 cm. The

405

Table 3. Early to middle Miocene radiolarians at Site 495.jo

ch

s

LU

α>cα>u0

üα>

idd

ε

ene

ioc

>

ea

rl

Zones

D. pettersoni

D. alata

C. costata

S. wolffii

S. delmontensis

Site 495

(core -section,

interval in cm)

18-2,

18-5,

18-6,

19-1,

19-4,

19-6,

20-1,

20-4,

20-6,

21-2,

21-4,

21-6,

22-2,

22-5,

23-2,

23-4,

23-6,

24-1,

24-3,

24-7,

25-1,

25-3,

25-5,

26-1,

26-3,

26-5,

27-2,

27-5,

28-2,

28-6,

29-2,

29-5,

30-1,

30-2,

31-2,

31-5,

32-2,

32-5,

33-2,

33-5,

34-2,

34-6,

35-1,

35-3,

36-1,

36-3,

37-1,

37-3,

90-92

90-93

100-102

119-121

8-10

8-10

60-62

60-62

60-62

70-72

70-72

70-72

30-32

41-43

35-37

42-44

42-44

15-17

40-42

40-42

30-32

30-32

30-32

30-32

30-32

30-32

55-57

39-41

59-61

59-61

19-21

19-21

30-32

30-32

30-32

30-32

39-41

39-41

20-22

30-32

26-28

2-4

78-80

78-80

45-47

71-73

21-23

21-23

slid

e)

en

sity

(t

ho

usa

nd

s p

er:

ad

iola

ria

n D

cr

12.6

25.2

18.9

25.2

6.3

18.9

25.2

25.2

25.2

25.2

25.2

12.6

18.9

25.2

25.2

18.9

18.9

18.9

6.3

12.6

18.9

18.9

18.9

18.9

18.9

25.2

18.9

25.2

25.2

25.2

25.2

18.9

18.9

18.9

18.9

25.2

25.2

12.6

12.6

12.6

12.6

12.6

12.6

12.6

12.6

12.6

12.6

12.6

ao

or,

mo

de

rate

, g

oo

d)

ese

rva

tio

n (

α.

M

M

M

M-P

P

P

M

M

M

M

M

M

M

M

M

M

M

M

M-P

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

iart

us

hu

gh

e:

Q

2.9

1.5

13

-

\son

iia

rtu

s p

ett

en

Q

3.3

l.S

2.2

F

R

R

-

-

an

tep

en

ult

ima

idym

oc

yrti

s

Q

.67

.15

-la

tic

on

us

idym

oc

yrti

s

Q

1.7

1.0

1.0

R

F

R

F

F

F

to

>£

1

1

•d

ymo

cyrt

is

Q

F

F

F

.95

.95

2.0

1.0

1.8

2.2

.25

R

R

r

r

r

r

r

pri

sma

tic

aid

ymo

cyr

tis

Q

r

r

r

r

r

r

r

r

r

.22

.06

.05

r

r

r

.10

.09

,10

.12

.16

.15

.12

.15

tub

ari

aid

ymo

cyr

tis

Q

-t-

+

+

r

r

.11

.16

.56

.56

.53

.33

.71

.67

.91

.56

.70

.67

.63

.30

.83

.43

R

R

F

.16

.12

.12

.38

.29

.30

.27

.21

vio

lina

idym

oc

yrti

s

Q

.86

.71

1.0

.50

.90

1.9

2.9

F

F

3.3

2.9

1.3

1.4

2.0

1.1

2.5

.83

1.0

.77

1.6

.33

.12

+

on

ton

ge

nsi

sic

tyo

co

ryn

e

Q

R

R

R

-

-

-

ala

tao

rca

do

spyr

is

Q

-

-

-

-

+

r

+

r

R

R

R

r

R

r

.05

-

.02

r

-

-

i ate

uc

hu

so

rca

do

spyr

ii

Q

-

-

-

-

-

-

-

+

-

-

-

-

-

-

de

nta

tao

rca

do

spyr

is

Q

-

-

-

-

-

.01

.09

R

R

R

r

r

R

r

r

r

r

r

r

-

-

-

-

~ker

aeir

iosp

yris

pai

-

-

+

r

-

-

-

R

R

R

F

F

.78

.08

r

R

R

R

-

-

-

uro

po

rair

iosp

yris

sta

•~j

-

-

-

-

-

-

-

-

-

-

r

r

-

r

.95

1.9

F

F

F

F

F

R

R

r

R

r

r

+

r

-

-

-

co

rnu

tayr

toc

ap

seila

ü

-

-_

-

-

-

R

R

R

R

r

R

r

R

R

R

R

R

R

F

R

R

F

r

R

R

R

R

R

R

R

R

R

R

R

F

F

F

F

F

R

F

F

F

tetr

aper

ayr

toca

psei

la

+

-

_

+

-

r

F

F

F

F

F

F

F

F

F

R

F

F

F

F

R

F

F

F

F

F

-

r

F

F

R

F

F

F

F

F

F

C

ccF

F

C

C

C

'tho

pe

ra b

aα

-

-

tera

ith

op

era

ne

o

r

r

r

+

r

r

-

+

-

+

+

-

-

-

-

tbto

'th

op

era

re

n.

-

-

r

r

R

R

r

r

+

-

r

r

r

r

r

r

+

R

R

R

R

r

r

r

r

r

r

-

-

-

a e

lon

ga

tayc

hn

oc

an

om

-

-

+

-

r

R

R

-

-

+

+

-

-

-

-

-

-

r

F

F

R

R

R

R

R

m a

uda×

vch

no

dic

tyu

-

-

RR

R

r

r

r

r

r

r

r

r

r

+

+

r

+

r

R

r

r

r

r

r

r

r

R

r

r

r

r

R

R

R

r

r

r

r

r

r

r

2to

|

CO

oo

ito-

-

_

-

-

+

-

-

-

R

r

r

R

-

-

-

r

r

-

-

-

R

r

r

r

r

r

r

R

R

R

R

R

R

F

R

R

r

R

r

R

r

r

r

i/mon

tens

is'ic

hoco

rys

di

to

F

F

F

FF

R

R

F

F

R

R

R

F

F

F

F

F

F

F

F

F

F

F

F

F

F

F

C

cc

F

F

F

F

F

F

C

C

ccF

F

F

F

F

oiff

ii'ic

hoco

rys

w

CO

R

R

R

RF

F

F

R

R

-

r

r

r

R

R

R

R

R

F

R

R

R

F

F

F

F

R

F

F

F

C

F

F

F

F

r

-

-

+

-

-

-

-

bra

mle

ttei

irpoc

anop

sis

-

-r

-

r

r

R

r

r

r

R

F

R

R

R

-

F

R

R

R

R

r

R

r

r

r

r

R

R

R

R

R

R

F

F

R

r

r

r

r

r

r

r

cinguia

ta

11g.

------r

r

+

r

R

R

F

F

F

F

F

F

F

R

F

F

F

F

F

F

R

R

R

R

R

R

R

R

: fa

vosa

arpo

cano

psis

o

-

-

+

-

-

-

-

-

-

-

-

-

-

-

-

+

-

-

r

+

r

r

r

r

r

r

r

r

r

r

r

r

r

R

R

R

R

R

R

r

r

R

osta

taC

alo

cycl

etta c

r

-

-

-+

+

-

-

-

r

r

-

-

F

F

F

F

F

F

F

F

F

R

R

r

R

r

r

r

r

r

-

-

-

•irgi

nis

alo

cycl

ett

a u

R

-_

FR

R

F

F

F

F

F

F

F

C

C

ccccccccF

F

F

F

F

C

c

F

F

C

F

F

F

F

F

F

F

F

F

F

F

artu

s co

rbula

o

εa.

R

R

R

RR

R

R

R

+

-

-

-

-

+

+

r

+

+

+

+

+

art

us

do

liolu

mh

orm

ost

ich

o

-

r

r

r

-

-

tus

co

ron

aip

ho

stic

ho

ar

-

-

r

-

-

R

r

R

+

-

-

r

r

r

-

-

-

R

R

R

R

r

r

+

r

-

r

r

r

r

r

r

r

r

r

r

r

-

-

-

-

r

r

r

r

r


406



Table 4. Pliocene to Quaternary radiolarians at Site 496.E

po

chs

>roc

α>

ua

t

σ

cen

Plio

Zones

C. tuberosa

A. ypsiion

A. angulare

P. prismatium

S. pentas

Site 496

(core section,interval in cm)

1-1,

1-5,

2-2,

2-4,

3-4,

5-6,

6-4,

7-2,

8-2,

9 - 1 ,

10-2,

11-2,

12-2,

13-1,

14-2,

15-4,

1 6 - 1 ,

17-2,

19-4,

20-2,

21-6,

22-4,

23-6,

24-3,

25-4,

26-4,

27-4,

28-3,

50-52

50-52

70-72

70-72

60-62

50-52

117-119

50-52

34-36

99-101

98-100

60-62

6-8

6-8

6-8

110-112

30-32

91-93

41-42

60-61

86-88

65-67

30-32

121-126

40-42

5-7

29-31

90-92

Iide)

ds p

er s

c

Ra

dio

lari

an

De

ns

ity

(th

ou

sa

6.2

1.3

1.3

1.3

12.5

6.2

1.3

1.3

2.5

6.3

2.5

6.2

.3

6.2

2.5

.3

6.2

6.2

2.5

6.2

6.2

.3

2.5

2.5

1.3

1.3

6.2

1.3

, g

oo

d)

O)

Pre

serv

ati

on

(p

oo

r, m

od

era

tG

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

M

M

M

M

M

G

G

Bu

ccin

osp

ha

era

inva

gin

ata

-

Co

llosp

ha

era

tu

be

rosa

r

-

-

-

-

-

So

len

osp

ha

era

om

nit

ub

us

-

-

Axo

pru

nu

m a

ng

elin

um

-

-

-

-

-

_

-

-

-

-

-

r

F

R

F

R

R

R

r

R

R

R

F

Did

ymo

cyr

tis

avi

ta

-

-

r

r

Did

ymo

cyr

tis

pe

nu

ltim

a

-

-

-

R

R

R

Did

ymo

cyr

tis

tetr

ath

aia

mu

s

F

F

R

F

F

R

R

F

R

F

R

r

r

F

R

r

R

R

R

R

r

r

R

-

-

-

Am

ph

irh

op

aiu

m

ypsi

ion

R

R

R

R

r

R

R

R

R

R

F

F

F

F

F

R

R

r

r

-

-

-

-

-

-

-

Sp

on

gas

ter b

erm

ing

ha

mi

-

-

Sp

on

gas

ter

pe

nta

s

-

-

-

-

Sp

on

gas

ter

tetr

as

R

R

r

r

r

r

r

r

r

R

R

R

R

r

r

R

R

R

r

r

r

R

-

-

Sp

on

go

dis

cus

am

bu

s

-

-

Lyc

hn

od

icty

um

a

ud

ax

-

-

F

F

Pte

roc

an

ium

pri

sma

tiu

m

-

-

-

-

-

Sti

ch

oc

ory

s p

ere

gri

na

-

-

V

R

An

tho

cy

rtid

ium

an

gu

lare

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

r

r

-

-

Ca

loc

ycle

tta

ro

bu

sta

gro

up

-

-

La

mp

roc

yrti

s h

ete

rop

oro

s

-

-

-

La

mp

roc

yrti

s n

eo

he

tero

po

ro

-

-

-

-

-

-

-

-

R

-

-

La

mp

roc

yrti

s n

igri

nia

e

F

R

R

R

F

F

R

R

R

R

F

F

R

R

R

F

R

R

r

r

-

r

-

R?

-

-

Th

eo

co

ryth

ium

tra

ch

eliu

m

r

r

-

-

r

-

-

-

_

-

-

-

-

r

r

-

-

r

-

.04

.08

-

-

-

Th

eo

co

ryth

ium

ve

tulu

m

-

-

-

-

-

_

-

-

-

-

-

-

-

-

-

-

-

.15

-

F

R

Ph

orm

ost

ich

oa

rtu

s c

orb

uia

F

F

F

R

F

F

R

R

F

F

F

F

F

F

F

R

F

F

F

F

F

F

F

R

R

R

R

F

Ph

orm

ost

ich

oa

rtu

s d

olio

lum

-

-

-

r

r

Ph

orm

ost

ich

oa

rtu

s fi

stu

la

-

-

-

-

rS

pir

oc

yrti

s g

yro

sca

lari

s

r

-

r

r

r

-

r

-

RS

pir

oc

yrti

s sc

alar

is

R

r

r

r

r

r

r

r

-

F


presence of Didymocyrtis αvitα, Spongaster tetras, Sti-chocorys peregrina, Lamprocyrtis nigriniae, and Theo-corythium trachelium in Samples 498A-8-7, 24-26 cmand 498A-9,CC suggest the Pliocene or Quaternary, al-though these are single occurrences in very sparse as-semblages. Cores 498A-10 through -15 are highly dis-turbed drilling breccia with very little recovery. Radio-larians are extremely rare, and early Miocene throughPliocene forms are mixed.

SITE 499

Site 499 is on the Trench floor, just seaward of theTrench axis. It consists of trench-fill turbidites overlying

a lithologic sequence similar to Site 495, the oceanic ref-erence site.

The first fourteen cores are all trench-fill turbidites,and are probably younger than 320,000 to 400,000 yrs.,based on the latest occurrence of Axoprunum angelinumbetween Samples 499-14-3, 37-39 cm and 499-15-3, 102-103 cm. It is not possible to place the Pliocene/Pleisto-cene boundary with certainty because of the absence ofPterocanium prismatium and the extremely low num-bers of Lamprocyrtis heteroporos, L. neoheteroporos,Theocorythium vetulum, and T. trachelium. However,Anthocyrtidium angulare occurs in Cores 18 and 19,and the lower boundary of that zone is therefore tenta-

407


Table 5. Middle Miocene radiolarians at Site 496.

uo

LU

cuoi

idle

ε

i/l ioc

ene

>α>

Zones

D. petterssoni

D. aiata

^ ^ ^ ^ ^ ^

C. costata

Site 496


29-3,

30-3

31-3,

33-5,

34-2,

34-5,

35-2,

35-5,

36-2,

36-4,

37-1,

39-1,

40-1,

40-7,

40-42

45-47

12-14

9-11

25-27

20-22

60-62

80-81

90-92

50-52

72-74

10-12

15-17

18-20

slid

e)d

iola

rian

Den

sity

(th

ousa

nd

oc

1.0

18 5

6.3

1.0

2.5

.30

2.5

6.3

12.6

6.3

.50

.50

.50

2.5

8oσ>

eser

vatio

n (p

oor,

mod

erat

e,α_

P

M

M

M

M

M

M

M

M

M

M-P

M-P

M-P

M

artu

s hu

ghes

i

Q

.97

_ar

tus

pett

erss

oni

Q

5.0

-dy

moc

yrtis

an

tepe

nulti

ma

Q

2.3

_

dym

ocyr

tis

Iatic

onus

Q

4.3p

idym

ocyr

tis

mam

mife

ra

Q

-

.06

dym

ocyr

tis

pris

mat

ica

Q

r

.20

.20

.12

dym

ocyr

tis

tuba

ria

Q

-

.08

.20

.36

.44

.16

.67

.51

.20

.60

1.0

2.2

idym

ocyr

tis

vio

lina

Q

.97

.60

1.3

.44

.21

.85

.57

.40

1.0

1.4

3.9

ctyo

cory

ne o

nton

gens

is

Q

_

orca

dosp

yris

aia

ta

Q

.02

-

-

-

-

orca

dosp

yris

den

tata

Q

.02

-

-

-

R

r

r

-

-

-

-

-rio

spyr

is p

arke

rae

_

-

-

riosp

yris

sta

urop

ora

- j

r

R

R

R

r

R

R

R

F

R

R

/rto

caps

eiia

cor

nuta

-

-

r

-_

Cyr

toca

psel

la t

etra

pera

-

-

-

-

-_

thop

era

neot

era

-

-

-

-

thop

era

renz

ae

- j

r

-

-

-

-

r

-

R

r

/chn

ocan

oma

eion

gata

-

-

-

-

-

-_

-

-

-

-

-

ychn

odic

tyum

aud

a×

-1

r-

-

r

icho

cory

s ar

mat

a

CO

-

-

R

-rFRFR

R

F

icho

cory

s de

lmon

tens

is

CO

Rp

C

C

ccccccF

ccc

icho

cory

s w

oiffi

i

CO

F

CC

ccFFFF

C

cc

irpoc

anop

sis

bram

lette

i

cj

rrr

RRrR

R

R

irpoc

anop

sis

cing

ulat

a

0

rFR

R

rR

F

RR

irpoc

anop

sis

favo

sa

cj

-

rr

Rr

-r

rR

Rr

ilocy

clet

ta v

irgin

is

Cj G

-

-

-

-

RP

rr

P

R

R

F

CCC

C

cFFF

CC

c

^orm

ostic

hoar

tus

corb

ula

p

-

-

norm

ostic

hoar

tus

dolio

lum

-

-

-

phos

ticho

artu

s co

rona

CO

R

-r

-

--RR

---

-


tively drawn between Samples 499-19-3, 110-112 cmand 499-19-6, 10-12 cm (Table 7).

In Sample 499-23-1, 30-83 cm, there is a red-streaked,gray siliceous mud that stratigraphically comprises theentire upper Miocene. Three samples from this unit aretabulated in Table 8. Percentage abundances clearly showthe morphotypic top of Diαrtus petterssoni, the mor-photypic top of Didymocyrtis Iaticonus, the transitionof Didymocyrtis antepenultima to D. penultima, anddecreasing numbers of Stichocorys delmontensis whileS. peregrina increases in preparation for that transition.

Lower in that section, Samples 499-23-1, 102-104 cmand 499-23,CC (10-12 cm) are clearly from the Dor-cadospyris aiata Zone, based on the relative abundanceof D. aiata and D. dentata. That transition marks thetop of the Calocycletta costata Zone between Samples499-23,CC (10-12 cm) and 499-24-1, 16-18 cm. Theearliest occurrence of C. costata, between Samples 499-25-3, 100-102 cm and 499-25-4, 102-104 cm indicatesthe bottom of that zone and the top of the Stichocoryswoiffii Zone. Relative abundances for these and otherMiocene radiolarians are recorded in Table 9.

Hole 499B was washed to a sub-bottom depth of 201meters, the level of Core 499-23. The first core catchershowed three lithologies. The uppermost, a light-col-ored coarse layer, contains a mixed assemblage of about25% upper Miocene Didymocyrtis antepenultima Zoneand about 75% middle Miocene Dorcadospyris aiataZone. A sample from the dark green gray mud at 9 to 11cm has a good assemblage from the D. antepenultima

Zone, with a very small number of middle or lowerMiocene species. The light nannofossil ooze at the bot-tom contains an assemblage from the D. aiata Zone.Samples 499B-2-1, 80-82 cm and 499B-3-1, 0-1 cm areassigned to the Calocycletta costata Zone on the pres-ence of Dorcadospyris dentata, Eucyrtidium diaphanes,and greater numbers of Liriospyris stauropora than itsdescendant L. parkerae. In Sample 499B-3-4, 48-50 cm,the absence of C. costata, D. dentata, and L. stauro-pora, and the presence of Lychnocanoma eiongata andabundance of Stichocorys woiffii, indicate the lowerMiocene S. woiffii Zone. Samples 499B-4-1, 67-69 cmand 499B-6-1, 58-60 cm are evidently below the lowestoccurrence of S. woiffii and contain greater numbers ofDidymocyrtis tubaria than D. violina, so they are as-signed to the Stichocorys delmontensis Zone. No sam-ples from Cores 499B-5 or -7 were examined, and Cores499B-8 and -9 are barren of radiolarians. This termina-tion of radiolarian occurrences in the S. delmontensisZone, followed by a barren interval and then basalt,corresponds to the oceanic reference Site 495.

SITE 500

Site 500 is at the base of the Middle America Trenchlandward slope, at the junction of the slope and theTrench floor. The lithology and radiolarian stratigraphyis similar to that of Sites 499 and 495.

Radiolarians are moderately well preserved and di-luted with terrigenous debris in Quaternary Cores 500-1

408


Table 6. Pliocene to Quaternary radiolarians at Site 497.E

po

chs

> •

<oc

atei

α

<L>

Plio

cen

Zones

C. tuberosa

A. ypsilon

A. anguiare

P. prismatium

S. pentas

Site 497


1-3,

2-3,

3-4,

4 - 1 ,

5-3,

6 - 1 ,

7-2,

9-4,

10-4,

11-3,

12-3,

13-4,

15-4,

16-4,

17-3,

18-5,

19-2,

19-5,

20-2,

20-5,

23-6,

25-4,

26-3,

28-2,

29-7,

30-6,

31-2,

33CC,

34-3,

35-2,

36-8,

37-6,

38-5,

39-2,

41-2,

42-7,

80-82

80-82

10-12

74-76

81-83

12-14

80-82

23-25

51-53

13-15

57-59

14-16

70-72

30-32

26-28

10-12

120-122

91-93

8-10

90-92

30-34

40-42

16-18

81-83

43-45

13-15

43-45

14-16

24-26

41-43

35-37

44-46

90-95

52-55

53-55

36-37

sity

ide)

Ra

dio

lari

an

De

n(t

hous

and

s p

er

si0.3

2.5

2.5

2.5

6.3

2.5

6.3

6.3

2.5

12.6

6.3

2.5

6.3

6.3

12.6

6.3

2.5

2.5

2.5

2.5

2.5

2.5

2.5

12.6

2.5

2.5

2.5

6.3

12.6

1.3

12.6

0.5

0.5

2.5

18.9

12.6

| (P

oo

22CO

or,

mo

de

rP

rese

rvat

ion

(p

o

G

G

M

G

G

G

G

G

G

G

G

G

G

G

G

M

M

M

M

MP

M

M

M

M

M

M

M

M

M

M

M

M

M

M

P

nvag

inat

aB

ucci

nosp

haer

a /

-

-

eros

a

1to

-c

S•o

δ

R

-

-

-

-

-

3•o

a1

Soi

enos

pha

era

oi

----

?lin

umA

×op

runu

m a

ngt

--r

R

R

R

R

R

R

R

r

r

r

R

FF

F

F

F

F

R

F

R

R

R

R

R

F

R

R

itaD

idym

ocyr

tis a

v,

-

-

.12

.02

-

-

.08

.03

.02

.15

.34

.40

.40

.08

.01

.008

nulti

ma

Did

ymoc

yrtis

pe

-

-

.02

-

-

.50

.60

2.6

.24

1.

.02

rath

alam

uD

idym

ocyr

tis t

et

R

R

R

R

R

R

R

R

R

R

R

R

r

r

R.08

.04

.04

.01

-

r

r

ypsi

lon

Am

phirh

opal

um

R

R

R

R

R

r

F

F

R

r

r

-

r

r

-

r

-

-

-

-

<ngh

ami

Spo

ngas

ter

berm

,

-

-

-

is

Spo

ngas

ter

pent

i

-

.08

.16-

.32

.36

.10

.08

.12

.09

.17

.76

.13

2.6

2.8

.04

.47

.09

Spo

ngas

ter

tetr

a

R

R

F

R

F

R

R

r

R

R

r

r

r

.32

.44

.32

.24-

.76

.84

.25

R

.28

.80

.23

.18

.23

.08

2.6

1.2

.08

.04

.04

3

Spo

ngod

iscu

s a

n

-

-

-

-

-

-

-

auda

×Ly

chno

dict

yum

-

-

-

-

-

-

-

-

-

-

-

-

-

-

'<m

atiu

m

Q.

.3

11

-----------------------

grin

a1

Stic

hoco

rys

pere

----.24

.63

R

F

F

R

F

F

F

F

R

R

R

angu

iare

An th

ocy

rtid

ium

-

-

-

-

R

r

-

r

-

-

-

-

-us

ta g

roup

Cal

ocyc

letta

rob

-

-

-

-

lero

poro

sLa

mpr

ocyr

tis h

e,

.008

-

.04

.04

-

.12

.08

-

.16

.08

.08

-

-

-

-

-

r

-

-

-

-

-

o

ohet

erop

oiLa

mpr

ocyr

tis n

e

-

-

.03

.06

.15

.12

.12

.08

-.08

-

.08

.02

-

.04

-

-

.04

-

-

-

-

-

-

-

irini

aeLa

mpr

ocyr

tis n

ic,

F

R

FR

F

F

R

R

r

.30

.56

.03

.04

.02

.04

-

-

-.04

-

.28

.07

.20

.36

.40

.04

.03

-

-

-

-

-

+

trac

heliu

m1

The

ocor

ythi

um ;

-

-

-

-

-

-

r

r

-

-

-

.21

-.02

.04

-

-

r

--

-

ε.3

Th

eo

cory

thiu

m i

-

-

-

-

.05

.06

.06

4.

F

F

F

R

F

R

R

r

R

R

R

R

F

R

R

R

R

R

R

"us

corb

ula

| P

ho

rmo

stic

ho

an

F

F

R

F

F

F

F

F

F

F

F

F

F

F

F

F

F

F

F

F

F

F

F

F

R

F

R

F

F

F

F

F

R

R

r

ε

'us

do

liolu

Ph

orm

ost

ich

oan

-----R

r

F

R

-

-

R

R

'us

fistu

laP

ho

rmo

stic

ho

an

-

-

-

-

r

r

r

r

r

r

scal

aris

Sp

iro

cyrt

is g

yro,

r

r

r

r

r

r

r

r

r

ris

Sp

iro

cyrt

is s

cala

R

R

R

R

R

r

r

r

r

r

r

r

r

r

r


through -10, and in core catchers from Cores 500A-1and -2. Relative abundances are tabulated in Table 10.

There is a contact between Quaternary trench tur-bidites and middle Miocene foraminifer-nannofossilooze in Section 500-10-2, and the sediments below thatcontain radiolarian assemblages corresponding to thoseof the early and middle Miocene of Site 499 (Table 11).Samples from Cores 500-13 and -14 are placed in theStichocorys delmontensis Zone. These assemblages ap-pear better-preserved than those of the corresponding

cores at Sites 499 and 495, and diatoms are far moreabundant in strewn slides. However, just as at Sites 499and 495, the remaining cores above basalt are barren ofradiolarians.

INTERPRETATIONS

Reliability of Events

The correlation of sequences by means of microfos-sils is commonly plagued by contradictions in the data,

409


lableE

poc

hsQ

uat

ern

ary

Plio

cene

7. Pliocene to Quaternary radiolaπans

Zones

C. tuberosa

A. ypsilon

A. angulare

P. prismatium

Site 499


1-1, 106-108

2-2, 109-111

3_4, 144-146

5-3, 72-74

6-2, 131-136

7-1, 37-39

9CC, 16-18

10-8, 8-10

11-3, 41-43

12-3, 141-143

13-4, 48-50

14-3, 37-39

15-3, 102-103

16-1, 0-3

17-3, 58-60

17-5, 58-60

18-1, 100-102

19-3, 110-112

19-6, 10-12

21-1, 45-47

22-1, 50-52

22-6, 100-102

at Site 499

Ra

dio

lari

an

De

nsi

ty (

thou

sand

s p

er s

lide)

2.5

6.3

.25

.25

.25

.25

.25

2.5

.25

6.3

1.3

6.3

18.9

12.6

18.9

25.2

6.3

12.6

18.9

6.3

18.9

12.6

Pre

serv

atio

n (m

od

era

te, g

oo

d)

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

M

M

M

Buc

cino

spha

era

in v

agin

a ta

Col

losp

haer

a tu

bero

sa

A×

opru

num

ang

eiin

um

Did

ymoc

yrtis

a vi

ta

Did

ymoc

yrtis

pen

ultim

a

i i

i

1 1

1 -s

1

1 1

1

- r\ r\

rr r!rR r!

F

F

F

F

F r

R r r !

Did

ymoc

yrtis

te

trat

hala

mus

Am

phirh

opal

um

ypsi

lon

Spo

ngas

ter

pent

as

Spo

ngas

ter

tetra

s

Lych

nodi

ctyu

m a

uda×

R R r +!

R r r

F F F •

F F

F F

R

R R

R R

F F

F R r

R

F F R

R R R

R R r +:

R R r

R F R

R r R

R r - R

r + - R

r - . 02 .05 -

r - .04 .05 -

r - .02 .08 -

Pte

roca

nium

pris

mat

ium

Stic

hoco

rys

pere

grin

a

Anth

ocy

rtid

ium

ang

ular

e

Lam

proc

yrtis

het

erop

oros

Lam

proc

yrtis

neo

hete

ropo

ros

-

r!

rl -

rl -

R : -rl -

r . 0 3

r

- - - . 03 .02

- - - .01 .005

- - - .008 .008

Lam

proc

yrtis

nig

rinia

e

The

ocor

ythi

um

trac

heiiu

m

The

ocor

ythi

um v

etul

um

Pho

rmos

ticho

artu

s co

rbui

a

Spi

rocy

rtis

gyr

osca

laris

Spi

rocy

rtis

sca

iaris

F r F - r

R r F - R

F F - R

F F - R

F F

R R

F R

R r R

R F

F r r ! F r

.38 - - F - r

.02 - - F - r

.05 .01 - R r r

.008 .008 - R

.02 - .005 R r

.04 .01 .02 R r r

.02 .05 .02 R

.06 - - F r r

.03 .02 - F r

.02 .02 .80 F

.04 .005 .11 F

- .06 F r r


manifested by the crossing of lines connecting the sameseries of events in several sequences. It becomes neces-sary, therefore, to judge which of the contradicting linesmost likely approximates an isochron. In earlier investi-gations of DSDP materials, we have routinely used arather poorly defined scheme of classifying each eventin each sequence as stratigraphically "poor," "moder-ate," or "good" on the basis of the abundance andpreservation of each taxon (Riedel and Sanfilippo,1971, p. 1545). Authors working on non-DSDP mate-rials (Brower et al., 1978; Millendorf et al., 1978) havemodified the "relative biostratigraphic value" devisedby McCammon (1970), which is based on the propor-tion of investigated assemblages that contain the speciesbeing evaluated, taking account of vertical range, lateralpersistence, and facies independence. The first of theseprocedures (the earlier DSDP investigations) is unsat-

isfactory in that the factors involved in evaluating thestratigraphic reliability are too few and not clearly de-fined; the second (the modified "relative biostratigraph-ic value" method) also suffers from being oversimplis-tic. The probabilistic procedures for determining the mostlikely order of biostratigraphic events (Hay, 1972; Hayand Steinmetz, 1973; Worsley et al., 1973) do not takeaccount of differences in the levels of reliability of par-ticular events at particular sites.

In an attempt to overcome some of these inadequa-cies, we have elaborated on a concept initiated by aJOIDES panel in order to develop an index of reliabilityof events that takes account of abundance of the taxonconcerned, the extent of our understanding of the evolu-tion of the taxon, the ease of distinguishing it from co-occurring forms, the preservation of the assemblagerelative to the susceptibility to solution of the taxon con-

410


Table 8. Late Miocene radiolarians at Site 499.

en.CooQ.

LLJ

Φ

2 8to O

Zones

D. antepen-ultima

Site 499

(core-section.interval in cm)

23-1, 20-22

23-1, 40-42

23-1, 69-71

α>

lids

pe

r s

sand

3O

4-1

>

an D

en

sit

CO

O

CO

25.2

18.9

18.9

goo

d)

rate

,

α>^ 3O

E

ion

(p

oor

CO

0 )

α_

M

N

M

ughe

si

|."3

Q

.67

.76

2.9

ette

rsso

ni

|CO

Q

-

.06

.19

11&

1Q

.29

.70

1.4

o

yrti

s la

tic

O

ε

-.09

.63

CO

timyr

tis p

ern

1O

O

4.4

1.5

.19

a ba

cca

1

thi

.25

.25

.03

3 ne

ote

ra

1•c

-

-

.02

ten:

co

1QGO

"SCO

.95

1.0

1.4

CD

rys

pere

gr

o6

"SCO

.80

.38

.19

rys

wo

lffi

oCJ

O,O

CO

-

-

.01


Table 9. Early to middle radiolarians at Site 499.

Zones

Site 499

(core-section,interval in cm) cc Q Q Q Q. Q

O D O

ε ε εQ Q Q Q Q

!° !« !C >; £ £ &11

IIIco Co ò

δ •S

+rJ •K. 4-J " S

II 1

D. alata

C. costata

S. wolffii

23-1, 102-10423,CC,10-1224-1, 16-1824-3, 84-8625-3, 100-10225-4, 102-104

18.9

12.6

25.2

25.2

18.9

12.6

.05!* - .05* ?/ ?/

- - - ?/ n2.2

.59

.25

r 1.1

r .41

.18 .63

.36 .42

- R

- R

R .02

r -

.50 R

F F

F R

R R

r R -

R R -

- r R- R R

R R R

F R R -

C F R R

C R R

C F r

F C - -

F C - -

F F + -

R C -

R C -

R R - F

Note: Symbols as for Table 1. * = probable downworking (this chalky sample had some dark in i t ) , •f• = relative abundances indeterminate, only cortical shells are preserved.

cerned, low abundances due to dilution, intermittenceor constancy of occurrence of the taxon in the sequence,the relation of the locality to the periphery of the area ofdistribution of the taxon, and the effects of reworking.Some of these factors are numerical, and all are placedarbitrarily on a numerical scale of values 0.1, 0.25, 0.5,0.75, and 1 (Table 12).

In applying this procedure here for the first time, wefind the following explanations of the factors necessary.

A) Abundance of taxσn is divided into three ranges,as indicated in Table 12. This refers not to relative abun-dance but to the absolute number of specimens of thetaxon found in the samples near the limits of the strati-graphic range. The purpose is to reflect the greater like-lihood of having found the true stratigraphic limit if

more than five specimens have been observed in eachsample.

B) Average relative abundances of ancestor and de-scendant above and below evolutionary transitions. Forexample, if the descendant is 6 times as abundant as theancestor above the event, and the ancestor is 1.5 timesas abundant as the descendant below the event, theaverage is slightly less than 4, and would score 0.75.

C) Type of event, reflecting whether or not the an-cestor or descendant of the taxon concerned is known,and the type of evolutionary interpretation. "Crypto-genetic origin" refers to the earliest occurrence of a tax-on for which there are several or no candidate ancestors.An extinction is regarded as "cryptogenetic" when thetaxon left no known evolutionary descendant, and "evo-

411


Table 10. Quaternary radiolarians at Site 500.

Epo

chs

Qua

tern

ary

Hole 500 andHole 500A


1-3, 4-6

2 - 1 , 50-52

3-4, 70-72

4-2, 6-8

5-2, 34-36

7-7, 90-92

8-2, 116-118

9-2, 130-132

9-4, 77_79

10-2, 21-23

A 1, CC, 11-13

A 2,CC

Rad

iola

rian

Den

sity

(tho

usan

ds p

er s

lide)

6.3

6.3

1.3

1.3

1.3

1.3

0.5

1.3

0.3

0.3

1.3

1.3

Pre

serv

atio

n (m

od

era

te,

good

)

G

G

G

G

G

G

G

M

M

M

M

M

Buc

cino

spha

era

inva

gina

ta

Col

losp

haer

a tu

bero

sa

A×

op

run

um

ang

elin

um

Did

ymocy

rtis

avi

ta

Did

ymoc

yrtis

penulti

ma

- r -

- r -

r R -

R R:

R R:

R R

R R

Did

ymocy

rtis

te

trat

haia

mus

Am

ph

irh

op

aiu

m y

psilo

n

Spo

ngas

ter p

enta

s

Spo

ngas

ter

tetr

as

Lyc

hn

od

icty

um

aud

a×

R R r

F R r

F R R

R F R

R R

R R R

F - R

F R R

F R R

F R R

R R R

R R R

Pte

roca

nium

pr

ism

atiu

m

Stic

hoco

rys

pere

grin

a

Anth

ocy

rtid

ium

ang

uiar

e

Lam

proc

yrtis

het

erop

oros

Lam

proc

yrtis

neo

hete

ropo

ros

- + '. -

Rl - .33

R.' -

R

R

Lam

proc

yrtis

ni

grin

iae

The

ocor

ythi

um

trac

heliu

m

The

ocor

ythi

um

vetu

lum

Pho

rmos

ticho

artu

s co

rbia

Spi

rocy

rtis

gy

rosc

alar

is

Spi

rocy

rtis

sc

alar

is

F .03 F r r

F .02 F - R

R - F - -

R - F - -

R - F - -

R - F - -

.20 - - F - -

.38 - - F R -

.67 - - F - -

1.0 .33 - F - -

.07 - - F - -

. . . F - -


Table 11. Early to middle Miocene radiolarians at Site 500.

Epo

chs

early

Mio

cene

j m

iddl

eM

ioce

ne

Zones

D. alata

C. costata

S. woiffii

S. deimontensis

Site 500


10-2, 127-129

10-3, 127-129

11-3, 73-75

11-4, 32-34

12-3, 127-129

13-2, 50-52

13-3, 60-62

14-2, 10-12

14-4, 30-32

Rad

iola

rian

Den

sity

(tho

usan

ds

per

slid

e)

6.3

12.6

2.5

6.3

18.9

18.9

18.9

18.9

6.3

Pre

serv

atio

n (p

oor,

mod

erat

e)

P

M

M

M

M

M

M

M

M

Dia

rtus

hug

hesi

Dia

rtus

pet

ters

soni

Did

ymoc

yrtis

ant

epen

ultim

a

Did

ymoc

yrtis

lat

icon

us

Did

ymoc

yrtis

mam

mife

ra

- - - - 1.9

- - - - 1.7

1.3

.95

Did

ymoc

yrtis

pris

mat

ica

Did

ymoc

yrtis

tub

aria

Did

ymoc

yrtis

vio

iina

Dic

tyoc

oryn

e on

tong

ensi

s

Dor

cado

spyr

is a

lata

r .91 - r

r .57 - r

r .80

r r 1.1

r 4.4 8.3

r .52 .35

r .25 .25

.11 .07 -

.13 .06

Dor

cado

spyr

is d

enta

ta

Lirio

spyr

is p

arke

rae

Lirio

spyr

is s

taur

opor

a

Cyr

toca

psei

ia c

ornu

ta

Cyr

toca

psei

ia t

etra

pera

- R r r F

- R - R F

r .30 .70 F

r .02 .13 F F

- - - F C

- - - R C

F C

R F

R F

Lith

oper

a ne

oter

a

Lith

oper

a re

nzae

Lych

noca

nom

a el

onga

ta

Lych

nodi

ctyu

m a

uda×

Sitc

hoco

rys

arm

ata

- r R -

r -

R - R R

r - F

- R r F

- R R -

R

R

F

Stic

hoco

rys

deim

onte

nsis

Stic

hoco

rys

woi

ffii

Car

poca

nops

is b

ram

iette

i

Car

poca

nops

is c

ingu

iata

Car

poca

nops

is

favo

sa

C R r r

F F R r -

F F r • -

C C r R -

C C r F R

C - - R R

F - - R R

C R R

F R R

Cal

ocyc

letta

cos

tata

Cal

ocyc

letta

virg

inis

Pho

rmos

ticho

artu

s co

rbui

a

Pho

rmos

ticho

artu

s do

lioiu

m

Sip

host

icho

artu

s co

rona

F C r - -

F F - - -

R F r - r

F C -

- C -

- F r r

R -

C -

R -


lutionary" when it is confidently interpreted as havingterminating its lineage. As with evolutionary extinc-tions, a score of 0.75 is assigned to morphotypic limitsthat bracket known evolutionary transitions, as well asto earliest morphotypic occurrences of an evolutionaryoffshoot from a persistent lineage, because in both ofthese cases the limit would be extended by searching

through much larger samples (Fig. 2). By "evolutionarytransition" is meant the level at which the numericaldominance changes from ancestor to descendant.

D) Ease of distinguishing the taxon from co-occur-ring fossils. The reliability of species distinctions is wellknown to vary widely, and the scoring of this factortherefore ranges from the minimum value to the max-

412


Table 12. Scoring of the value of a particular biostratigraphic event at a particular locality.

______̂ MultiplierFactor " —^__^^^

A) Abundance of taxon (numbers of speci-mens observed in each sample)

B) Average relative abundances ofancestor and descendant above andbelow the event (applies only to evolu-tionary transitions)

C) Type of event

D) Ease of distinguishing the taxon fromco-occurring fossils

E) Is the assemblage well preserved,relative to the preservation threshold ofthe taxon concerned, or are samplesimmediately above or below the eventpoorly preserved or highly diluted?

F) Constancy of occurrence in thesequence, above or below the event(not applicable to evolutionarytransitions)

G) Relation of locality to periphery ofarea of distribution of taxon

H) Effects of reworking

0.10

Difficult

No

0.25

1

Near periphery

0.50

2-5

< 2 ×

Cryptogenetic originor extinction

Moderately easy

Uncertain, or somedifficulty dueto preservation

Unknown

The limit as here interpreted may be unreliabledue to reworking

0.75

2-5 ×

Evolutionary extinction, ormorphotypic limit, orevolutionary offshoot

Interrupted

Occurrences outside thisrange are certain to bedue to reworking

1.00

>5

> 5 ×

Evolutionary transition

Very easy

Yes

Constant

Well within

No reworking

Morphotypicupper limitof ancestor

Morphotypiclower limit of -an evolutionaryoffshoot

Evolutionary transition

Morphotypic lower limitof descendant

MORPHOLOGY

Figure 2. Diagram illustrating the use of terms describing stratigraphicevents associated with lineages and evolutionary offshoots.

imum. This is a less objective factor than some otherslisted.

E) Assemblage preservation relative to the preserva-tion threshold of the taxon concerned. This is clearly amore pertinent factor than an evaluation of the overallpreservation of the assemblage. A median score is givenwhen one is uncertain whether an absence or low abun-dance is due to solution or when solution has removedfeatures necessary for identification from some speci-mens in the sample.

This category is also used to downgrade the score ofan upper morphotypic limit above which (or a lowermorphotypic limit below which) absence of the taxon issuspected to be due to dilution or dissolution.

F) Constancy of occurrence in the sequence, withinthe stratigraphic range of the taxon. This is not appli-cable to evolutionary transitions because these are lo-cated by the changing proportions of ancestor and de-scendant, not by the limit of range of a morphotype.The need to consider intermittence of occurrence is clear-ly demonstrated by the highly variable abundances ofsome rather common species throughout their ranges, asdescribed by Westberg and Riedel (1978).

G) Relation of locality to area of distribution of thetaxon. It seems obvious that the earliest and latest rec-ords of a taxon near the periphery of its area of distribu-tion will be less reliable stratigraphically than those wellwithin the boundaries. Also, for localities whose rela-tion to biogeographic distributions have changed throughtime (because of seafloor spreading or changes in oce-anic conditions), this factor may be evaluated differ-ently for the upper and lower limits of the same taxon.

H) Effects of reworking. The index of reliability ofan event is downgraded slightly if the investigator isconfident of having recognized that an extension ofstratigraphic range was due to reworking, and is down-graded more if he is less confident. This downgrading isdone on the assumption that the reworking is taken intoconsideration in interpreting the upper or lower limit,and the reworked occurrences are excluded from therange. This is clearly an area of subjective judgment, inwhich the investigation must take account of sedimento-logical evidences of disturbance, the abruptness of ap-pearances and disappearances of the taxon in other se-quences, evidence of reworking of other taxa into theassemblage, and so on.

As an example of the application of this index, theupper limit of Anthocyrtidium angulare scored 0.5 oneach factor A, C, D, E, and G, 0.75 on factor F, and

413


1.0 on factor H. Multiplying these together yields 0.02,which converts to 2°7o (the first entry for Site 495 inTable 13).

In designing this index of stratigraphic reliability, wehave attempted to formulate a procedure that will be ap-plicable not only to radiolarians but to all microfossilgroups. Thus it should be as useful for resolving con-flicts between various groups used for stratigraphic cor-relation, as it is for the various taxa of a single group(see the following section and Riedel and Westberg, inpress).

Correlations

Figure 3 shows the correlations among all of the siteson this Leg. Most of the correlation lines present noproblem, but there are two conflicts that the reliabilityindex scores shown in Table 13 help to resolve.

The order of the evolutionary transition from Didy-mocyrtis violina to D. mammifera, and the morpho-typic top of the Carpocanopsis favosa (Events 37 and38) is reversed at Site 499 as compared to Sites 495 and500, and although the reliability index for Event 37 isequally low at all three sites, the index for Event 38 atSite 500 is higher than that at Site 499, indicating thatthe order at Site 500 is more likely correct.

The morphotypic top of Carpocanopsis cingulata(Event 36) at Site 500 occurs above the evolutionarytransition from Dorcadospyris dentata to D. alata (Event34); however, the reliability index for Event 36 at thatsite is lower than the indices at Sites 495, 499, and 496.Therefore the sequence at these sites is considered thecorrect one.

Relative Abundances of Families

Because Sites 494 and 496 are located on the Guate-malan margin and Site 495 is on the Cocos Plate, it is ofinterest to investigate whether the radiolarian assem-blages on the continental side of the Trench differ sig-nificantly from those on the oceanic side.

The radiolarian species treated in the main body ofthis paper were selected (from the much larger totalpresent) because of their known stratigraphic useful-ness. It seems appropriate, however, to approach thegeographic-environmental question by examining dif-ferences in the assemblages at the family level, becausethis provides a practical means of recording the entireassemblages.

We selected approximately time-equivalent portionsof the sequences at the three sites (S. pentas Zonethrough Quaternary), and assigned 300 specimens fromeach sample to 14 family categories and the suborderSpyrida. Because we were working at the same time onmaterial from DSDP Leg 68, we gathered the same dataon samples from Hole 503A (4°03'N, 95°38'W) for anadditional oceanic reference site. Relative percentagesare shown in Tables 14 through 17, together with indica-tions of the preservations and the degree of dilution byvolcanic ash, diatoms, or other terrigenous materials.

We also compared a data set from a previous publica-tion (Riedel and Sanfilippo, 1978a) as a third exampleof a non-open-ocean environment. These data are con-

stant-numerator percentage estimates of the same 15family categories in samples from the Pliocene CapoRossello section in southern Sicily.

These constant-numerator percentage estimates showmore details of the contributions of rare taxa to theassemblages but are too time-consuming to apply rou-tinely in preliminary studies such as most of those forDSDP Initial Reports.

After eliminating two families whose abundanceswere almost always less than 1%, the data from eachsite were transformed to an M × M matrix of correla-tion coefficients between pairs of families, as a first stepin the cluster analysis program of Davis (1973, p. 467).The dendrograms of the margin sites show a cluster offour families, spyrids, plagoniids, theoperids, and pter-ocorythids (Fig. 4). The same families are clustered inthe samples from the Sicilian Pliocene, with the additionof cannobotryids and artostrobiids, but no such struc-ture is seen in the dendrograms of the oceanic sites.

Table 18 shows correlation coefficients for some fam-ily pairs in all of the sites examined. Nine of the four-teen pairs (rows 1-9, Table 18) have high positive ornegative correlation in the margin sites and at CapoRossello, but insignificant correlations at the open oceansites. Three pairs (rows 10-12, Table 18) correlate sig-nificantly at the margin sites, Capo Rossello, and at Site495, but not at Site 503. Two family pairs (rows 13 and14, Table 18) have significant negative correlations at allsites investigated.

These findings represent a substantial advance be-yond the tentative indications of covariances resultingfrom previous work on the Capo Rossello assemblages(Riedel and Sanfilippo, 1978a) and augur well for thepossibility of using the relative proportions of high-lev-el radiolarian taxa in order to recognize restrictedpaleoenvironments.

SPECIES LIST

The purpose of this list is to provide bibliographic references to thetaxa mentioned in this chapter. The only literature references given areto the original description, and to our present concept of the species, ifdifferent from or more detailed than the original one.

Alievium supβrbum (Squinabol)Theodiscus superbus Squinabol, 1914, p. 271, pi. XX(I), fig. 4.Alievium superbus (Squinabol), Pessagno, 1972, p. 302, pi. 24,figs. 5, 6, pi. 25, fig. 1.

Amphipyndax stocki (Campbell and Clark)StichocapsaiP.) stocki Campbell and Clark, 1944b, p. 44, pi. 8,figs. 31-33.Amphipyndaxstocki (Campbell and Clark), Foreman, 1968, p. 78,pi. 8, figs. 12a-c.

Amphirhopalum ypsilon HaeckelAmphirhopalum ypsilon Haeckel, 1887, p. 522; Nigrini, 1971, p.447, pi. 34.1, figs. 7a-c.

Anthocyrtidium angulare NigriniAnthocyrtidium angulare Nigrini, 1971, p. 445, pi. 34.1, figs.3a, b.

Artophormis gracilis RiedelArtophormis gracilis Riedel, 1959, p. 300, pi. 2, figs. 12, 13.

Axoprunum angelinum (Campbell and Clark)Stylosphaera angelina Campbell and Clark, 1944a, p. 12, pi. 1,figs. 14-20.Stylatractus universus Hays, 1970, p. 215, pi. 1, figs. 1, 2.Axoprunum angelinum (Campbell and Clark), Kling, 1973, p. 634,pi. 1, figs. 13-16, pi. 6, figs. 14-18.

414


Table 13. Radiolarian events at Leg 67 sites.

Zones

C. tuberosa

A. ypsilon

A. angulare

P.prismatium

S. pent as

S. peregrina

D.penultima

D. ante-penultima

D.petterssoni

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

Events

Bm C. tuberosa

Tm A. angelinum

Tm A. angulare

Tm L. neoheteroporos

T. vetulum —T. trachelium

Bm A. angulare

Tm P. prismatium

Tm S. peregrina

D. avita —D. tetrathalamus

Tm. L. audax

Tm P. doliolum

Bm P. prismatium

D. penultima —D. avita

S. pent as —S. tetras

Tm S. ambus

S. berminghami —S. pentas

Tm C. robusta grp.

Bm S. ambus

S. delmontensis -S. peregrina

Tm D. hughesi

Tm D. ontongensis

D. petterssoni —D. hughesi

Bm D. hughesi

Bm D. ontongensis

495

—

3-6, 20-224-1, 75-77

24-1, 75-774-3, 75-77

145-2, 40-425-5, 40-42

256-4, 10-126,CC (3-4)

27-1, 70-727-3, 70-72

99-3, 75-779-6, 26-28

756-1, 92-9411-1, 60-62

311-1, 60-6211-3, 60-62

3711-3, 60-62ll,CC(4-6)

1911-3, 60-62ll,CC(4-6)

1411-3,60-6212-3, 30-32

412-7, 31-3313-5, 54-55

1812-7, 31-3313-5, 54-55

y15-5, 30-3216-2, 30-32

3815-5, 30-3216-2, 30-32

5015-5, 30-3216-2, 30-32

Q

y15-1, 30-3216-2, 30-32

3716-6, 30-3217-1, 30-32

7517-6, 30-3218-2, 90-92

5017-6, 30-3218-2, 90-92

2518-6, 101-10219-1, 119-121

3818-6, 101-10219-1, 119-121

25

2-2,3-4,

14-315-3

17-518-1

17-518-1

16-121-1

19-319-6

499

109-111144 146

7, 37-39, 102-103

75, 58-60, 100-102

6, 58-60, 100-102

7,0-3, 45-47

38, 110-112, 10-12

6

Holes

500 494

3-4, 70-72 1-5, 59-614-2, 6 8 1-6, 59 61

59-2, 130-132 A2-6,9-4,77-79 A4-1,

7510-2, 21-23Al.CC (11-13)

3

A17-2A18-1

A18-1A20-2

729-311-375—

—

—

—

—

, 64-66, 90-92

7_

—

—

—

, 90-92, 110-11212

497

1-3, 80-822-3, 80-82

127-2, 80-829-4, 23-25

7513-4, 14-1615-4, 70-72

516-4, 30-3217-3, 26-28

1415-4, 70-7217-3, 26-28

618-5, 10-1219-2, 120-122

5—

25-4, 40-4226-3, 16-18

7525-4, 40-4226-3, 16-18

3—

33,CC (14-16)34-3, 24-26

56—

35-2, 41-4336-8, 35-37

934-3, 24-2635-2, 41-43

9—

496

1-1, 50-521-5, 50-52

1915-4, 110-11216-1, 30-32

7521-6, 86-8822-4, 65-67

3—

23-6, 30-3224-3, 121-126

923-6, 30-3224-3, 121-126

3

26-4, 5-727-4, 29-31

7525-4, 40-4227-4, 29-31

326-4, 5-727-4, 29-31

5026-4, 5-727-4, 29-31

19—

—

—

415


Table 13. (Continued).

Zones

D.petterssoni

D. alata

C. costata

S. wolffii

S. delmont-ensis

Events

25 Bm P. doliolum

26 Tm C. bramlettei

27 Bm D. petterssoni

28 Tm D. alata

29 Tm C. cornuta

30 Tm L. renzae

31 L. renzae —L. neotera

32 Bm P. corbula

33 Tm C. costata

34 D. dentata —D. alata

35 L. stauropora -~L. parkerae

36 Tm C. cingulata

37 D. violina —D. mammifera

38 Tm C. favosa

39 Tm L. elongata

40 Bm C. costata

41 Bm D. dentata

42 £>. tubaria —Zλ violina

43 Bm L. stauropora

44 Bm 5. wo/#i7

45 Zλ prismatka —D. tubarius

495

19-1, 119-12119-4, 8-10

319-1, 119-12110-4 fl-if)l7"*T, O I v

3819-6, 8-1020-1, 60-62

7519-6, 8-1020-1, 60-62

3819-6, 8-1020-1, 60-62

5019-6, 8-1020-1, 60-62

3819-6, 8-1020-1, 60-62

5020-6, 60-6221-2, 70-72

3822-5, 30-3223-2, 41-43

3823-6, 41-4324-1, 15-17

5023-6, 41-4324-1, 15-17

5024-1, 15-1724-3, 40-42

5024-1, 15-1724-3, 40-42

524-7, 40-4225-1, 30-32

1926-3, 30-3226-5, 30-32

1929-5, 19-2130-1, 30-32

7529-5, 19-2130-1, 30-32

3829-5, 19-2130-1, 30-32

3830-2, 30-3231-2, 30-32

1333-5, 30-3234-2, 26-28

56—

499

23.CC (10-12)24-1, 16-18

10023,CC (10-12)24-1, 16-18

10024-1, 16-1824-3, 84-86

5024-3, 84-8625-3, 100-102

524-1, 16-1824-3, 84-86

2524-3, 84-8625-3, 100-102

2524-3, 84-8625-3, 100-102

50B3-1.0-1B3-4, 48-50

75B3-1, 0-1B3-4, 48-50

38B3-1, 0-1B3-4, 48-50

75B3-4, 48-50B4-1, 67-69

75

Holes

500 494

10-3, 127-12911-3, 73-75

5010-3, 127-12911-3, 73-75

10010-2, 21-2310-2, 127-129

2511-3,73-7511-4, 32-34

511-4, 32-3412-3, 127-129

5011-4, 32-3412-3, 127-129

5011-4, 32-3412-3, 127-129

5011-4, 32-3412-3, 127-129

3812-3, 127-12913-2, 50-52

3811-4, 32-3412-3, 127-129

1912-3, 127-12913-2, 50-52

7513-3, 60-6214-2, 10-12

50

497 496

29-3, 40-4230-3, 45-47

7529-3, 40-4230-3, 45-47

9—

30-3, 45-4731-3, 12-14

730-3, 45-4731-3, 12-14

1330-3, 45-4731-3, 12-14

2834-5, 20-2235-2, 60-62

2530-3, 45-4735-2, 60-62

13—

30-3, 45-4731-3, 12-14

50—

31-3, 12-1433-5, 9-11

25

Note: Presented are core-section and intervals in cm of the samples bracketing the event. The number below the sample numbers indicates the index ofreliability (see text). Tm and Bm indicate the morphotypic top or bottom of a species; arrows indicate evolutionary transitions.

416


Epoch Zone

C. tu-beroseA. yp•silonA. an-

oulare

P. pris•matium

Events495 499 500

Holes

494 497 496

,Bm C. tuberosa 1

Tm A. angelinum 2

Tm A. angulare 3 ,

T m L neoheteroporos 4,

T. vetulum —*-T. trachelium

Bm A. angulare

~Tm P. prismatium

.TmS. peregrina

D. avita — * -D. tetrathalamus

Tm L. audax

Tm A. doliolum

Bm P. prismatium

D. penultima — * •D. avita

S. pentas—*~S. tetras

Tm S. ambus

S. berminghami—S. pentas

Tm C. robusta grp.

Bm S. ambus

- S. delmontensis — *S. peregrina

. hughesi

Tm D. ontongensis

s D. petterssoni — » -D. hughesi

Bm D. hughesi

BmD, ontongensis

Bm P. doliolum

Tm C. bramlettei

Bm D. petterssoni

Tm D. alata

Tm C. cornuta

Tm L. renzae

L. renzae — * -L. neotera

Bm P. corbula

Tm C. costata

^ D. dentata — * -D. alata

L. stauropora — » -L. parkerae

Tm C. cingulata

D. violina •-

D. mammifera

Tm C. favosa

Tm L. elongate

Bm C. costata

BmD. dentata

D. tubaria *•

D. violina

Bm L. stauropora

Bm S. wolffii

43

44

25

100

125

150 ?

175 I

200

225

250

275

300

325

350

Figure 3. Correlation of radiolarian events in Leg 67 sites. (Each rectangular box represents a core with its numbershown inside. Numbers labeling correlation lines correspond to the radiolarian events listed on the left. Tm in-dicates the morphotypic top of a species and Bm the morphotypic bottom of a species; an arrow denotes evolu-tionary transitions. Sample intervals bracketing events, and a reliability index for each event, are given in Table13.)

417


Table 14. Percent estimate of radiolarian families and the suborder Spyrida at Site 494.

Site 494


1-1, 32-34

2-3, 32-34

3-2, 32-34

4-4, 32-34

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

A

2-6, 29-31

4-1, 1-3

5-1, 60-62

7-3, 60-62

8-1, 70-72

9-1, 20-24

10-1, 133-135

11-1, 70-72

14-3, 12-14

16-1, 87-91

17-2, 64-68

18-1, 90-92

18-4, 64-66

19-1, 7-9

20-2, 110-112

20-3, 76-78

1Io§3

1

3

2

5

2

1

1

1

1

1

1

1

0

0

0

2

2

0

0

1εso

5

10

6

8

6

8

9

3

6

7

21

10

4

9

8

12

10

13

6

15

oto

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1§a5

1

1

2

1

1

0

1

0

1

0

2

0

0

0

0

1

0

0

1

1I&33

36

33

35

52

47

36

41

46

52

56

42

31

59

47

52

42

42

62

65

1C

8

5

8

14

13

12

9

9

11

9

9

15

11

7

13

10

9

11

15

4

1£.o0fS

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

1

11

12

11

11

11

11

7

5

13

11

5

11

13

9

16

16

9

8

14

10

«

5

3

5

4

4

5

3

4

3

1

0

2

6

0

0

1

2

2

0

0

I1Q ,

5

6

4

2

2

2

6

6

5

3

0

4

7

1

1

0

4

3

0

0

11110

9

10

10

3

5

13

13

5

3

1

4

8

4

1

1

6

6

1

1

cu

11s•<3

l

l

l

i

0

i

3

2

3

2

1

1

1

2

2

1

2

1

0

0

8

19

8

9

2

2

1

3

8

4

3

2

2

7

1

2

0

3

3

0

0

1

|6

5

9

8

2

4

8

6

2

4

5

4

10

7

9

5

10

8

2

3

o

0

1

1

0

1

0

2

2

1

1

0

2

1

0

1

0

1

1

1

1

gcα>

£

M

M

M

M

M

P

P

P

P

P

P

P

M

M

M

M

M

M

M

M

CΛ

Eou.αi

CO

o

Q

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

IOu_co

m

r

r

r

r

R

R

R

R

R

R

R

R

R

R

R

R

F

R

R

R

co

Q

50X

60A

50X

-

75X

75X

75X

50X

80X

90X

99X

95X

60DX

50X

95A

50DA

99X

99X

95X

95X

Note: In the Preservation column G indicates good, M moderate and P poor. In the next two columns,— indicates none, r, 0.01—0.1%, and R, 0.1 — 1%. The Dilution column indicates the percentage of non-radiolarian components in an average field: D for diatoms, A for volcanic ash, and X for other terrigenousmaterial.

Buccinosphaera invaginata HaeckelBuccinosphaera invaginata Haeckel, 1887, p. 99, pi. 5, fig. 11;Strelkov and Reshetnyak, 1962, p. 129 and 137, fig. 12; Nigrini,1971, p. 445, pi. 34.1, fig. 2; Knoll and Johnson, 1975, p. 63, pi. 1,figs. 3-6.

Calocyclas hispida (Ehrenberg)Anthocyrtis hispida Ehrenberg, 1873, p. 216.Calocyclas hispida (Ehrenberg), Riedel and Sanfilippo, 1978b, p.65, pi. 3, fig. 6.

Calocycletta costàta (Riedel)Calocyclas costata Riedel, 1959, p. 296, pi. 2, fig. 9; Riedel andSanfilippo, 1978b, p. 66, pi. 3, fig. 9.

Calocycletta robusta Moore groupCalocycletta robusta Moore, 1971, p. 743, pi. 10, figs. 5, 6.Calocycletta caepa Moore, 1972, p. 150, pi. 2, figs. 4-7.Calocycletta robusta Moore group Riedel and Sanfilippo, 1978b,p. 66, pi. 3, figs. 10, 11.

Calocycletta virginis HaeckelCalocyclas {Calocycletta) virginis Haeckel, 1887, p. 1381, pi. 74,fig. 4.Calocycletta virginis (Haeckel), Riedel and Sanfilippo, 1978b, p.66, pi. 3, figs. 13, 14.

Carpocanopsis bramlettei Riedel and SanfilippoCarpocanopsis bramlettei Riedel and Sanfilippo, 1971, p. 1597, pi.2G, figs. 8-14, pi. 8, fig. 7; 1978b, p. 67, pi. 4, fig. 6.

Carpocanopsis cingulata Riedel and SanfilippoCarpocanopsis cingulata Riedel and Sanfilippo, 1971, p. 1597, pi.2G, figs. 17-21, pi. 8, fig. 8; 1978b, p. 67, pi. 4, fig. 4.

Carpocanopsis favosa (Haeckel)Cycladophora favosa Haeckel, 1887, p. 1380, pi. 62, figs. 5, 6.Carpocanopsis favosa (Haeckel), Sanfilippo and Riedel, 1973, p.531.

Collosphaera tuberosa HaeckelCollosphaera tuberosa Haeckel, 1887, p. 97; Nigrini, 1971, p. 445,pi. 34.1, fig. 1; Strelkov and Reshetnyak, 1971, p. 336-337, pi. 4,figs. 24, 25; Knoll and Johnson, 1975, p. 63, pi. 2, figs. 1-3.

Cyrtocapsella cornuta HaeckeiCyrtocapsa {Cyrtocapsella) cornuta Haeckel, 1887, p. 1513, pi. 78;fig. 9.Cyrtocapsella cornuta Haeckel, Riedel and Sanfilippo, 1978b, p.68, pi. 4, fig. 17.

Cyrtocapsella tetrapera HaeckelCyrtocapsa {Cyrtocapsella) tetrapera Haeckel, 1887, p. 1512, pi.78, fig. 5.Cyrtocapsella tetrapera Haeckel, Riedel and Sanfilippo, 1978b, p.68, pi. 4, fig. 18.

Diartus hughesi (Campbell and Clark)Ommatocampe hughesi Campbell and Clark, 1944a, p. 23, pi. 3,fig. 12.Ommatartus hughesi (Campbell and Clark), Riedel and San-filippo, 1978b, p. 71, pi. 7, fig. 7.Diartus hughesi (Campbell and Clark), Sanfilippo and Riedel,1980, p. 1010, text-fig. 1, i.

Diartus petterssoni (Riedel and Sanfilippo)Cannartus{1) petterssoni Riedel and Sanfilippo, 1970, p. 520, pi.14, fig. 3; 1978b, p . 67, pi. 4, fig. 2.

418


Table 15. Percent estimates of radiolarian families and the suborder Spyrida at Site 496.

Site 496


1-1,

3-4,

5-6,

7-2,

9-1,

11-2,

13-1,

14-2,

15-4,

16-1,

19-4,

21-6,

22-4,

23-6,

24-3,

25-4,

26-4,

27-4,

28-3,

50-52

60-62

117-119

50-52

99-101

60-62

6-8

6-8

110-112

30-32

41-42

86-88

65-67

30-32

124-126

40-42

5-7

29-31

90-92

<llo

spha

erid

ae

<S

7

1

0

3

0

2

6

3

3

6

2

0

1

1

1

3

7

2

4

^.tin

omm

idae

8

7

5

6

5

5

13

16

7

6

11

8

10

11

16

24

48

17

17

11

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

1

0

>cco

disc

idae

ö5

3

1

3

0

1

0

0

3

1

1

3

1

1

0

0

4

3

3

G

1£22

18

37

33

20

35

25

45

46

29

34

50

50

43

48

48

19

44

18

'loni

idae

<c8

6

7

18

14

13

7

4

10

11

8

8

8

6

3

7

5

5

1

<olo

niid

ae

fc0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

1

thel

iidae

•Z

12

20

16

11

14

12

11

11

16

12

10

15

12

10

9

6

11

14

>yrid

a

5

7

3

5

7

6

6

1

2

7

6

3

2

3

3

1

1

1

3

agon

iidae

S:

7

7

4

L.

1

4

5

0

1

6

5

1

1

2

1

1

0

0

6

iβo

pe

rid

ae

9

10

6

5

12

7

8

4

3

7

10

4

3

6

4

L.

4

8

14

'rp

oca

niid

ae

<3

i

0

0

2

1

0

0

1

0

1

0

2

0

1

1

1

0

1

0

tero

co

ry th

ida

e

12

12

o

9

8

6

5

6

4

7

3

3

1

3

3

1

2

4

4-t

ost

rob

iida

e

7

9

11

4

11

7

13

8

6

6

7

6

4

11

9

4

4

5

14

inn

ob

otr

yid

ae

Q

0

0

1

0

1

2

0

0

0

1

1

1

3

0

0

0

0

0

0

ese

rva

tio

n

G

G

G

M

M

M

M

M

M

M

M

M

M

M

M

M

P

M

P

jlic

ate

Fo

rms

α

-------------------

oke

n F

orm

s

CO

r

r

r

r

r

r

r

r

r

r

r

r

r

r

r

r

R

r

R

iluti

on

Q

80X

60XD

50X

50X

50X

SOX

50X

50X

70X

40X

70X

80X

90X

90X

90X

95X

99X

99X

85X

Note: See Table 14 for explanations of symbols.

Diαrtuspetterssoni (Riedel and Sanfilippo), Sanfilippo and Riedel,1980, p. 1010, text-fig. 1, h.

Dictyocoryne ontongensis Riedel and SanfilippoDictyocoryne ontongensis Riedel and Sanfilippo, 1971, p. 1588,pi. IE, figs. 1, 2, pi. 4, figs. 9-11; 1978b, p. 68, pi. 5, fig. 1.

Dictyomitrα koslovαe ForemanDictyomitrα koslovαe Foreman, 1975, p. 614, pi. 7, fig. 4.

Dictyoprorα αmphorα (Haeckel) groupDictyocephαlus αmphorα Haeckel, 1887, p. 1305, pi. 62, fig. 4.Dictyoprorα αmphorα (Haeckel) group Nigrini, 1977, p. 250, pi. 4,figs. 1, 2.

Dictyoprorα mongolfieri (Ehrenberg)Eucyrtidium mongolfieri Ehrenberg, 1854, pi. 36, fig. 18, B lower.Dictyoprorα mongolfieri (Ehrenberg), Nigrini, 1977, p. 250, pi. 4,fig. 7.

Dictyoprorα urceolus (Haeckel)Dictyocephαlus urceolus Haeckel, 1887, p. 1305.Dictyoprorα urceolus (Haeckel), Nigrini, 1977, p. 251, pi. 4, figs.9, 10.

Didymocyrtis antepenultima (Riedel and Sanfilippo)Ommatartus antepenultimus Riedel and Sanfilippo, 1970, p. 521,pi. 14, fig. 4; Westberg and Riedel, 1978, p. 22, pi. 2, figs. 4, 5.Didymocyrtis antepenultima (Riedel and Sanfilippo), Sanfilippoand Riedel, 1980, p. 1010.

Didymocyrtis avita (Riedel)Panartus avitus Riedel, 1953, p. 808, pi. 84, fig. 7.Didymocyrtis avita (Riedel), Sanfilippo and Riedel, 1980, p. 1010.

Didymocyrtis laticonus (Riedel)

Cannartus laticonus Riedel, 1959, p. 291, pi. 1, fig. 5; Westbergand Riedel, 1978, p. 20, pi. 2, figs. 1-3.Didymocyrtis laticonus (Riedel), Sanfilippo and Riedel, 1980, p.1010, text-fig. 1, e.

Didymocyrtis mammifera (Haeckel)Cannartidium mammiferum Haeckel, 1887, p. 375, pi. 39, fig. 16.

Cannartus mammiferus (Haeckel), Riedel, 1959, p. 291, pi. 1,

fig. 4.Didymocyrtis mammifera (Haeckel), Sanfilippo and Riedel, 1980,p. 1010.

Didymocyrtis penultima (Riedel)Panarium penultimum Riedel, 1957, p. 76, pi. 1, fig. 1.Ommatartus penuttimus (Riedel), Westberg and Riedel, 1978, p.22, pi. 2, figs. 6-8.Didymocyrtis penultima (Riedel), Sanfilippo and Riedel, 1980, p.1010, text-fig. 1, f.

Didymocyrtis prismatica (Haeckel)Pipettella prismatica Haeckel, 1887, p. 305, pi. 39, fig. 6.Didymocyrtis prismatica (Haeckel), Sanfilippo and Riedel, 1980,p. 1010, text-fig. 1, c.

Didymocyrtis tetrathalamus (Haeckel)Panartus tetrathalamus Haeckel, 1887, p. 378, pi. 40, fig. 3.Didymocyrtis tetrathalamus (Haeckel), Sanfilippo and Riedel,1980, p. 1010, text-fig. 1, g.

Didymocyrtis tubaria (Haeckel)Pipettaria tubaria Haeekel, 1887, p. 339, pi. 39, fig. 15; Riedel,1959, p. 289, pi. 1, fig. 2.Didymocyrtis tubaria (Haeckel), Sanfilippo and Riedel, 1980, p.1010.

Didymocyrtis violina (Haeckel)Cannartus violina Haeckel, 1887, p. 358, pi. 39, fig. 10; Riedel,1959, p. 290, pi. 1, fig. 3.Didymocyrtis violina (Haeckel), Sanfilippo and Riedel, 1980, p.1010, text-fig. 1, d.

Dorcadospyris alata (Riedel)Brachiospyris alata Riedel, 1959, p. 293, pi. 1, figs. 11, 12.Dorcadospyris alata (Riedel), Riedel and Sanfilippo, 1978b, p. 68,pi. 5, fig. 2.

Dorcadospyris ateuchus (Ehrenberg)Ceratospyris ateuchus Ehrenberg, 1873, p. 218.

419



Site 495


3-1,

3-3,

4 -1 ,

4-3,

5-2,

5-5,

6-4,

7-1,

7-3,

8-1,

9-3,

9-6,

10-4,

10-6,

11-3,

12-1,

12-5,

13-5,

14-3,

14-5,

15-3,

15-5,

16-4,

1-3

60-62

75-77

75-77

40-42

40-42

10-12

70-72

70-72

16-18

75-77

26-28

30-32

30-32

60-62

30-32

30-32

54-55

30-32

30-32

30-32

30-32

30-32

llosp

haer

idae

2

5

4

2

1

0

8

1

1

0

5

2

0

0

3

0

0

2

6

2

1

0

8

-.tin

omm

idae

-̂

15

10

10

6

12

13

29

17

26

17

15

11

19

22

25

29

32

26

18

18

20

19

10

^aco

disc

idae

*-

0

0

0

0

0

0

0

3

0

0

0

0

0

0

1

0

0

0

0

1

1

1

2

ccod

isci

dae

<35

2

0

2

2

1

1

1

0

0

1

1

1

1

2

5

1

3

1

3

3

2

6

ongo

disc

idae

%

33

26

35

34

37

55

33

23

34

40

27

27

30

24

32

16

27

29

31

25

30

21

18

'loni

idae

<C8

8

11

4

7

4

4

10

8

7

6

6

10

9

9

8

4

6

3

6

7

4

4

<olo

niid

ae

fc0

0

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

{hel

iidae

6

7

5

10

11

8

4

7

5

7

6

9

6

14

7

11

5

4

4

9

10

14

11

<yrid

a

6

5

5

7

6

3

2

7

4

5

6

8

3

2

5

1

1

3

4

8

3

2

7

agon

iidae

S:

5

3

8

10

5

3

1

5

1

1

3

5

1

3

1

1

0

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3

3

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3

6

1Iß5

7

10

8

6

4

5

6

6

4

8

7

8

8

6

9

7

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8

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16

14

15

rpoc

aniid

ae

a2

1

2

2

2

1

1

3

1

3

2

3

1

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0

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0

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0

1

0

ero

cory

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ae

7

14

4

6

1

3

3

4

3

4

9

4

5

2

3

5

3

6

5

4

4

4

3

tost

robi

idae

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5

12

4

7

8

6

8

13

10

11

8

15

14

13

6

15

19

11

16

13

4

16

9

'nno

botr

yida

e

c3l

1

l

2

1

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1

1

0

2

5

2

1

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1

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0

0

0

1es

erva

tion

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

M

Mili

cate

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Dorcαdospyris αteuchus (Ehrenberg), Riedel and Sanfilippo,1978b, p. 68, pi. 5, fig. 3.

Dorcαdospyris dentαtα HaeckelDorcαdospyris dentαtα Haeckel, 1887, p. 1040, pi. 85, fig. 6;Riedel and Sanfilippo, 1978b, p. 68, pi. 5, fig. 4.

Eucyrtidium diαphαnes Sanfilippo and RiedelEucyrtidium diαphαnes Sanfilippo and Riedel, in Sanfilippo et al.,1973, p. 221, pi. 5, figs. 12-14.

Eucyrtis microporα (Squinabol)Archicαpsα microporα Squinabol, 1903, p. 129, pi. 9, fig. 14.Eucyrtis microporα (Squinabol), Foreman, 1975, p. 615, pi. 21,figs. 2-5.

Lαmprocyrtis heteroporos (Hays)Lαmprocyclαs heteroporos Hays, 1965, p. 179, pi. 3, fig. 1.Lαmprocyrtis heteroporos (Hays), Kling, 1973, p. 639, pi. 5, figs.19-21, pi. 15, fig. 6.

Lαmprocyrtis neoheteroporos KlingLαmprocyrtis neoheteroporos Kling, 1973, p. 639, pi. 5, figs. 17,18, pi. 15, figs. 4, 5.

Lαmprocyrtis nigriniαe (Caulet)Conαrαchnium nigriniαe Caulet, 1971, p. 3, pi. 3, figs. 1-4, pi. 4,figs. 1-4.Lαmprocyrtis hαysi Kling, 1973, p. 639, pi. 5, figs. 15, 16, pi. 15,figs. 1-3.Lαmprocyrtis nigriniαe (Caulet), Kling, 1977, p. 217, pi. 1, fig. 17.

Eusyringium fistuligerum (Ehrenberg)Eucyrtidium fistuligerum Ehrenberg, 1873, p. 229.Eusyringium fistuligerum (Ehrenberg), Riedel and Sanfilippo,1978b, p. 68, pi. 5, figs. 6, 7.

Liriospyhs pαrkerαe Riedel and SanfilippoLiriospyris pαrkerαe Riedel and Sanfilippo, 1971, p. 1590, pi. 2C,fig. 15, pi. 5, fig. 4.

Liriospyris stαuroporα (Haeckel)Trissocyclus stαuroporus Haeckel, 1887, p. 987, pi. 83, fig. 5.Liriospyris stαuroporα (Haeckel), Riedel and Sanfilippo, 1971, p.1590, pi. 2C, figs. 16-19.

Lithochytris vespertilio EhrenbergLithochytris vespertilio Ehrenberg, 1873, p. 239; Riedel and San-filippo, 1978b, p. 69, pi. 6, fig. 4.

Lithocyclia ocellus Ehrenberg groupLithocyclia ocellus Ehrenberg, 1854, pi. 36, fig. 30.Lithocyclia ocellus Ehrenberg group Riedel and Sanfilippo, 1978b,p. 70, pi. 6, fig. 8.

Lithopera bacca EhrenbergLithopera bacca Ehrenberg, 1872, p. 314; Riedei and Sanfilippo,1978b, p. 70, pi. 6, fig. 9.

Lithopera neotera Sanfilippo and RiedelLithopera neotera Sanfilippo and Riedel, 1970, p. 454, pi. 1, figs.24-26, 28; Riedel and Sanfilippo, 1978b, p. 70, pi. 6, fig. 10.

Lithopera renzae Sanfilippo and RiedelLithopera renzae Sanfilippo and Riedel, 1970, p. 454, pi. 1, figs.21-23, 27; Riedel and Sanfilippo, 1978b, p. 70, pi. 6, fig. 11.

Lophocyrtis biaurita (Ehrenberg)Eucyrtidium biauritum Ehrenberg, 1873, p. 226.Lophocyrtis biaurita (Ehrenberg), Haeckel, 1887, p. 1411; Cita etal., 1970, p. 404, pi. 2, I, J, K.

Lychnocanoma elongata (Vinassa)Tetrahedrina elongata Vinassa, 1900, p. 243, pi. 2, fig. 31.

420



Hole 503A


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37-2, 50-54

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43-2, 50-54

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Lychnocanoma elongata (Vinassa), Riedel and Sanfilippo, 1978b,p. 70, pi. 7, fig. 4.

Lychnodictyum audax RiedelLychnodictyum audax Riedel, 1953, p. 810, pi. 85, fig. 9.

Phormostichoartus corbula (Harting)Lithocampe corbula Harting, 1863, p. 12, pi. 1, fig. 21.Phormostichoartus corbula (Harting), Nigrini, 1977, p. 252, pi. 1,fig. 10.

Phormostichoartus doliolum (Riedel and Sanfilippo)Artostrobium doliolum Riedel and Sanfilippo, 1971, p. 1599, pi.1H, figs. 1-3, pi. 8, figs. 14, 15; Westberg and Riedel, 1978, p. 20,pi. 3, figs. 10, 11.Phormostichoartus doliolum (Riedel and Sanfilippo), Nigrini,1977, p. 252, 253, pi. 1, fig. 14.

Phormostichoartus fistula NigriniPhormostichoartus fistula Nigrini, 1977, p. 253, pi. 1, figs. 11-13.

Podocyrtis mitra EhrenbergPodocyrtis mitra Ehrenberg, 1854, pi. 36, fig. B20; Riedel andSanfilippo, 1978b, p. 72, pi. 8, fig. 7.

Podocyrtis papalis EhrenbergPodocyrtis paplis Ehrenberg, 1847, fig. 2; Riedel and Sanfilippo,1970, p. 532, pi. 11, fig. 1.

Pterocanium prismatium RiedelPterocanium prismatium Riedel, 1957, p. 87, pi. 3, figs. 4, 5;Riedel and Sanfilippo, 1978b, p. 72, pi. 9, fig. 1.

Sethochytris triconiscus HaeckelSethochytris triconiscus Haeckel, 1887, p. 1239, pi. 57, fig. 13;Riedel and Sanfilippo, 1978b, p. 73, pi. 9, fig. 6.

Siphostichoartus corona (Haeckel)Cyrtophormis (Acanthocyrtis) corona Haeckel, 1887, p. 1462, pi.77, fig. 15.Phormostichoartus corona (Haeckel), Riedel and Sanfilippo, 1978b,p. 71, pi. 7, fig. 12.Siphostichoartus corona (Haeckel), Nigrini, 1977, p. 257, pi. 2,figs. 5-7.

Solenosphaera omnitubus Riedel and SanfilippoSolenosphaera omnitubus omnitubus Riedel and Sanfilippo, 1971,p. 1586, pi. 1A, fig. 24, pi. 4, figs. 1, 2; 1978b, p. 73, pi. 9, figs.8, 9.

Spirocyrtis gyroscalaris NigriniSpirocyrtis gyroscalaris Nigrini, 1977, p. 258, pi. 2, figs. 10, 11.

Spirocyrtis scalaris HaeckelSpirocyrtisscalaris Haeckel, 1887, p. 1509, pi. 76, fig. 14; Nigrini,1977, p. 259, pi. 2, figs. 12, 13.

421


Site 494COLLOSCOCCODSPYRIDPLAGONPTEROCTHEOPECARPOCCANNOBARTOSTPYLONILITHELACTINOSPONGO

.30 -.20 .11 .01 .08 .18 .27 .36 .46 .55 .65 .74 .84

Site 496COLLOSACTINOCOCCODLITHELSPYRIDPLAGONTHEOPEPTEROCARTOSTSPONGOCARPOCPYLONICANNOB

-.25 -.15 -.06 .03 .13 .22 .32 .41 .50 .60 .69 .79

Capo Rossello

r

COLLOSACTINOSPONGOLITHELPYLONICOCCODSPYRIDCANNOBPLAGONARTOSTTHEOPEPTEROCCARPOC

-.28-.17 -.07-.04 .15 .25 .36 .47 .58 .68 .79 .90 1.00

Site 495COLLOSPTEROCSPYRIDPLAGONCARPOCCANNOBPYLONISPONGOACTINOARTOSTCOCCODLITHELTHEOPE

.30.22- .14 -.06 .02 .10 .18 .27 .35 .43 .51 .59 .68

Site 503COLLOSPLAGONTHEOPECANNOBSPYRIDACTINOCARPOCPYLONIPTEROCCOCCODARTOSTSPONGOLITHEL

.20.14 - .07.01 .06 .12 .19 .25 .32 .38 .45 .51 .58

Figure 4. Dendrograms showing family clusters at margin Sites 494 and 496, Capo Rossello, and at oceanic Sites 495 and 503. (Values onthe horizontal axis are similarities.)

Spongaster berminghami (Campbell and Clark)Spongasteriscus berminghami Campbell and Clark, 1944a, p. 30,pi. 5, figs. 1, 2.Spongaster berminghami (Campbell and Clark), Riedel and San-filippo, 1978b, p. 73, pi. 2, figs. 14-16.

Spongaster pentas Riedel and SanfilippoSpongasterpentas Riedel and Sanfilippo, 1970, p. 523, pi. 15, fig.3; 1978b, p. 74, pi. 2, figs. 5-8.

Spongaster tetras EhrenbergSpongaster tetras Ehrenberg, 1860, p. 833; Riedel and Sanfilippo,1978b, p. 74, pi. 2, figs. 2, 3.

Spongodiscus ambus Sanfilippo and RiedelSpongodiscus ambus Sanfilippo and Riedel, 1974, p. 1024, pi. 1,figs. 12-14.

Stichocorys armata (Haeckel)Cyrtophormis armata Haeckel, 1887, p. 1460, pi. 78, fig. 17.Stichocorys armata (Haeckel), Riedel and Sanfilippo, 1971, p.1595, pi. 2E, figs. 13-15.

Stichocorys delmontensis (Campbell and Clark)Eucyrtidium delmontense Campbell and Clark, 1944a, p. 56, pi. 7,figs. 19, 20.Stichocorys delmontensis (Campbell and Clark), Westberg andRiedel, 1978, p. 22, pi. 3, figs. 1-5.

Stichocorys peregrina (Riedel)Eucyrtidium elongatum peregrinum Riedel, 1953, p. 812, pi. 85,fig. 2.Stichocorys peregrina (Riedel), Westberg and Riedel, 1978, p. 22,pi. 3, figs. 6-9.

Stichocorys wolffii HaeckelStichocorys wolffii Haeckel, 1887, p. 1479, pi. 80, fig. 10; Riedeland Sanfilippo, 1978b, p. 74, pi. 9, fig. 12.

Theocorys spongoconus KlingTheocorys spongoconus Kling, 1971, p. 1087, pi. 5, fig. 6.

Theocorythium trachelium (Ehrenberg)Eucyrtidium trachelius Ehrenberg, 1872, p. 312.Theocorythium trachelium (Ehrenberg), Nigrini, 1967, pp. 77-81,

422


Table 18. Correlation coefficients of some family pairs in the Neogeneof the eastern tropical Pacific and Sicily.

1. Plagoniids/theoperids2. Plagoniids/pterocorythids3. Theoperids/pterocorythids4. Theoperids/spyrids5. Spyrids/pterocorythids6. Theoperids/artostrobiids7. Spongodiscids/spyrids8. Spongodiscids/plagoniids9. Spongodiscids/pterocorythids

10. Plagioniids/spyrids11. Spongodiscids/artostrobiids12. Actinommids/spyrids13. Spongodiscids/theoperids14. Actinommids/plagoniids

GuatemalanMargin

494

+ 0.8+ 0.8+ 0.8+ 0.7+ 0.7+ 0.5-0.8-0.8-0.8+ 0.7-0.6-0.6-0.8-0.5

496

+ 0.8+ 0.7+ 0.5+ 0.6+ 0.6+ 0.6-0.6-0.7-0.6+ 0.8-0.4-0.5-0.7-0.5

CapoRossello

+ 0.6+ 0.6+ 0.5+ 0.5+ 0.5+ 0.7-0.8-0.9-0.6+ 0.8-0.8-0.4-0.9-0.5

Open Ocean

CocosPlate495

+ 0.2+ 0.06-0.04-0.06+ 0.1+ 0.02-0.03+ 0.02-0.2+ 0.6-0.5-0.7-0.5-0.8

East PacificRise503

+ 0.5-0.2-0.5+ 0.09+ 0.2-0.3-0.2-0.5+ 0.04+ 0.2+ 0.06-0.4-0.6-0.6

pi. 8, figs. 1, 2, pi. 9, figs. 1, 2 [including subspecies T. t. dianaβ];Riedel and Sanfilippo, 1978b, p. 76, pi. 9, fig. 17.

Theocorythium vβtulum NigriniTheocorythium vetulum Nigrini, 1971, p. 447, pi. 34.1, figs. 6a, b.

Theocotyle cryptocephala (Ehrenberg)Eucyrtidium cryptocephalum Ehrenberg, 1873, p. 227.Theocotyle cryptocephala cryptocephala (Ehrenberg), Riedel andSanfilippo, 1978b, p. 78, pi. 9, fig. 19.Theocotyle cryptocephala (Ehrenberg), Sanfilippo and Riedel, inpress.

Theocyrtis annosa (Riedel)Phormocyrtis annosa Riedel, 1959, p. 295, pi. 2, fig. 7.Theocyrtis annosa (Riedel), Riedel and Sanfilippo, 1978b, p. 78,pi. 10, fig. 3.

Thyrsocyrtis (Thyrsocyrtis) bromia EhrenbergThyrsocyrtis bromia Ehrenberg, 1873, p. 260; Riedel and San-filippo, 1978b, p. 78, pi. 10, figs. 4, 5.Thyrsocyrtis {Thyrsocyrtis) bromia Ehrenberg, Sanfilippo andRiedel, in press.

Thyrsocyrtis (Thyrsocyrtis) rhizodon EhrenbergThyrsocyrtis rhizodon Ehrenberg, 1873, p. 262.Thyrsocyrtis (Thyrsocyrtis) rhizodon Ehrenberg, Sanfilippo andRiedel, in press.

Thyrsocyrtis (Pentalacorys) triacantha (Ehrenberg)Podocyrtis triacantha Ehrenberg, 1873, p. 254.Thyrsocyrtis triacantha (Ehrenberg), Riedel and Sanfilippo, 1978b,p. 82, pi. 10, figs. 10, 11.Thyrsocyrtis (Pentalacorys) triacantha (Ehrenberg), Sanfilippoand Riedel, in press.

ACKNOWLEDGMENTS

This study was supported by National Science Foundation GrantNo. OCE79-20265. We are grateful to K. J. McMillen and AnnikaSanfilippo for reviewing the manuscript. M. A. Hanger competentlytyped the manuscript and assisted with the proofreading. Evelyn Por-tillo drafted the figures. Alexis Budai and W. Coulbourn advised us onthe statistical analysis of the data on abundances of families.

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