T.50 N.

DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY

W. E. WRATHER, DIRECTOR

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Kbc

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28

MINERAL INVESTIGATIONS

FIELD STUDIES MAP MF 28

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APP~OxLM>T [ r-l[AN D£C L1 NAl1 0N, 19'50

PREPARED fN COOPERATION WITH THE

U. S. ATOMIC ENERGY COMMISSION COLORADO GEOLOGICAL SURVEY BOARD

AND COLORADO METAL MINING FUND BOARD

1mc limrn 1

PRELIMINARY GEOLOGIC NlAP OF THE

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JUANITA ARCH QUADRANGLE, COLORADO By

E. M, Shoemaker Sca le 1 :24-CXXI

E=<=="====i=3.~':=::::E=3:=:::E=cr:==0'===================31 Mile 1955

Jee

Jk

Jms Js

1c 1m o 1mm 1

MINERAL INVESTIGATJONS

FIELD STUDIES MAP MF 28

38°30" 108°52'30'

Geology by E. M. Shoema ker, F. W. Cater, Jr., and E. J. McKay, 1949.

J,

SECTION ALONG LINE A-A'

~Cd~~ Je-gC/04(,±a 11A.rJ.3,.._o.J) ~

llllillli 1'_111 illlilllllii~ill_lillll~lliili l1lll ll1II IIII IIII 3 1818 00178410 5

Qal

EXPLANATION

Qal

Alluvium Light-red wind-deposited sand and silt on

benches and mesa tops; Recent valley fill and stream deposits.

Qg

Terrace gravels

Qls

Landslide deposits

UNCONFORMITY

Kd

Dakota sandstone Red and brown thin-bedded conglomeratic sand­

stone and minor amounts of carbonaceous shale. ·

Kbc

Burro Canyon formation White, gray, and red sandstone and conglom­

erate with interbedded green and purplish shale.

Jmb

Jms

Morrison formation Variegated shale and white and gray sandstone

and conglomerllte (Jmb); white and buff sand• stone with minor amounts of mudstone ( Jms ),

Js

Summerville formation Predominantly red and brown. thin-bedded mud­

stone; thin beds of chert and limestone.

Jee

Entrada sandstone and Carmel formation un­divided

Orange, buff, and white fine-grained sandstone at the top; red sandstone and mudstone at the base.

UNCONFORMITY

Jn

Navajo sandstone Gray to buff crossbedded fine-grained quartz

sandstone.

Jk

Kayenta formation Red, buff, gray, and lavender shale, siltstone,

and fine- to coarse-grained sandstone.

Jw

Wingate sandstone Fine-grained reddish-brown sandstone, thick­

bedded, massive, and crossbedded.

Chinle formation Bright red and red-brown mudstone, siltstone,

sandstone, and pebble conglomerate.

UNCONFORMITY

1mm

1ml

Moenkopi formation Sandy mudstone ( Rrn u ): conglomerate and con~

glomeratic sandstone (limm); and fine-grained sandstone and shale ( Rm l ),

Pc

Cutler formation Maroon and purple conglomerate and arkose and

red-brown sandy mudstone.

Pc

Rico formation Red arkose, red-brown mudstone, and gray

limestone.

Php

Phi

Hermosa formation Largely salt and gypsum (Php); limestone and

thin beds of shale, [not exposed in quad rangle] (Phi)

ec Qal Qg Qa\ Q Qa/ 1 ml

l'JSS.

Since the preparation of this mc;ip the age designa• tion c;if the Glen Cc;inyon group hc;is been changed in U. S. Geological Survey usage to Triassic and Ju• rassic; the age designation of the Wingate sandstone has been changed to Triossic; c;ind the age designation of the Navajo sandstone has been changed to Jurc;issic,

For sale Cy U.S. Geological Su Ney, price 50 cents

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Jw

Jn

Contact

Dashed where approximately located.

Indefinite contact Includes inferred contacts and indefinite bound­

aries of surficial deposits.

" -s--------Fault

Dashed where approximately located; dotted where concealed. U, upthrown side; D, downthroum side.

Strike and dip of beds

'x._ 90

Strike of vertical beds

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Horizontal beds

/0 (\N\

Generalized strike and dip of crumpled beds

vyv

Generalized strike of crumpled beds showing direction of dip

Anticline Showing trace of axial plane and bearing and

plunge of axis. Dashed where approximately located.

····-···+-····· Concealed anticline

Syncline Showing trace of axial plane and bearing and

plunge of axis. Dashed where approximately located.

······+······ Concealed syncline

...,,,---6000-.. -·

Structure contour Draum on top of Entrada sandstone. Short dashes

indicate projection above surface. Contour interoal 100 feet. Datum is mean sea level.

Structure depression contour

A' 8000'

7000'

Jee Js · 6000'

5000'

4000'

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