Trioctahedral Smectite in 

the Green River Formation, 

Duchesne County, Utah 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 967 

Trioctahedral Smectite in 

the Green River Formation, 

Duchesne County, Utah 

By JOHN R. DYNI 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 967 

An X-ray-diffraction study of clay minerals 

in some lacustrine rocks of Eocene age exposed 

in the southwestern part of the Uinta Basin 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1976 
UNITED STATES DEPARTMENT OF THE INTERIOR 

THOMAS S. KLEPPE, Secretary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Director 

Library of Congress Cataloging in Publication Data 

Dyni, John R. 

Trioctahedral smectite in the Green River Formation, Duchesne County, Utah. 

(Geological Survey Professional Paper 967} 

Includes bibliographical references. 

Supt. of Docs. No.: I 19.16:967 

1. Smectite-Utah-Duchesne Co. 2. Rocks, Sedimentary-Analysis. 3. Geology, Stratigraphic-Eocene. 4. X-rays-Diffraction. 

I. Title. II. Series. United States Geological Survey Professional Paper 967. 

QE391.S6D95 552'.5 76-43 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 

Stock Number 024-001-02821-2 
CONTENTS 

Page 

Abstract ............................................. . 1 Mineralogy-Continued 

Introduction .......................................... . 1 Other minerals ................................... . Geologic setting ....................................... . 1 Origin of smectite .................................... . Method of investigation ................................ . 4 Stratigraphic mineralogy .............................. . Mineralogy ........................................... . 5 Basin lithofacies ...................................... . Clay minerals ..................................... . 5 References cited ..................................... . 

ILLUSTRATIONS 

Page 

10 

10 

11 

13 

13 

Page 

FIGURE 1. Map showing locations of composite measured section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

2. Composite measured section of part ofthe Green River Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

3. Photograph showing units 3 - 18 exposed in roadcut along Utah Highway 33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

4. Photograph showing exposures of units 24- 71 near South Fork Avintaquin Creek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

5. Photograph showing exposures of units 54-118 near South Fork Avintaquin Creek . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

6. X-ray diffraction patterns of oil shale sample 49................................... . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

7. X-ray diffraction patterns of claystone sample 64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

8. X-ray diffraction patterns of purified clay fractions of several oil-shale samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

9. Distribution of structural charge for some trioctahedral smectites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

10. Diagram showing the eastward increase in resistivity of some Green River rocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

11. Schematic cross section of rock types and clay minerals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 

TABLES 

Page 

TABLE 1. Qualitative mineralogy of 17 samples of oil shale and claystone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

2. Chemical analysis of oil-shale sample 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

3. Semiquantitative spectrographic analysis of oil-shale sample 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

4. Semiquantitative determination of zinc in 17 whole-rock samples of oil shale and claystone . . . . . . . . . . . . . . . . . . . . . . . . . 12 

III 

TRIOCTAHEDRAL SMECTITE IN THE GREEN RIVER FORMATION, 

DUCHESNE COUNTY, UTAH 

By JOHNR. DYNI 

ABSTRACT 

Abundant trioctahedral smectite of probable authigenic origin 

and smaller amounts of discrete illite comprise a simple assemblage 

of clay minerals in a basin-edge sequence of lacustrine claystones 

and oil shales in the Eocene Green River Formation, southwest 

Uinta Basin, Duchesne County, Utah. Small amounts of chlorite 

and mixed-layer clay are present in a few samples; kaolinite is 

absent. 

The smectite is well crystallized and has a high expandable-layer 

content. Chemical analysis of partly purified material suggests an 

iron-bearing hectorite which contains notable quantities of zinc (740 

ppm (parts per million)), lithium (670 ppm), copper (175 ppm), and 

fluorine (0 .85 percent). 

No significant differences were noted in the clay-mineral content 

of the claystones and oil shales. However, of the associated 

carbonate minerals, calcite predominates in the oil shales, whereas 

dolomite strongly predominates in the claystones. This relationship 

suggests that the interstitial waters of the claystones during 

deposition and (or) lithification were more saline than those of the 

oil shales. The trioctahedral smectite evidently formed in a 

magnesium-rich lacustrine environment and appears to be part of a 

basin edge-to-center series of clay mineral facies-mixed detrital 

clay minerals to smectite to illite. 

INTRODUCTION 

This report presents the results of an X-ray-diffraction study of 17 samples of oil shale and claystone 

collected from a sequence of lacustrine rocks in the 

Eocene Green River Formation, which is exposed on 

the southwest side of the Uinta Basin, Duchesne 

County, Utah. The objective of this study was to 

identify the clay and associated minerals in some 

claystones and oil shales, and to determine the 

differences, if any, in the mineralogy of the two rock 

types. 

Earlier studies (Hite and Dyni, 1967; Hosterman 

and Dyni, 1972) suggest that several major lithofacies 

of the Green River Formation and associated 

Tertiary rocks in Colorado and Utah have 

characteristic assemblages of clay minerals. For 

example, in the deeper part of the Piceance Creek 

basin, east of the Uinta Basin, in western Colorado, 

the oil-shale facies of the Green River Formation 

contains moderate to sparse amounts of illite, 

abundant dolomite, and sodium carbonate minerals, 

whereas an underlying lithofacies composed of dark 

kerogenaceous shale contains abundant illite and 

lesser amounts of carbonate minerals. Older fluvial 

mudstones and associated rocks of the Wasatch 

Formation on the margins of the basin contain a mixed 

assemblage of kaolinite, illite, and mixed-layer clay. 

Overlying the oil-shale facies, a thick sequence of 

chiefly fine-grained clastic rocks contains smectite and 

illite. These data suggest the possibility that clay 

mineral assemblages in a time-stratigraphic sequence 

of rocks of the Green River Formation change 

progressively from a shoreward fluvial environment 

to a saline lacustrine environment at basin center. 

With this idea in mind, a sequence of lacustrine rocks 

was picked for study that was thought to represent 

shallow-water basin-margin sediments (claystones) 

that alternate with deeper water anoxic lacustrine 

sediments (oil shales). 

Acknowledgment. -The capable assistance of 

Robert W. Brown and Jerry D. Tucker in the sample 

preparation and X-ray work is gratefully acknowledged. 

GEOLOGIC SETTING 

The sequence of rocks studied includes most of the 

Parachute Creek Member of the Eocene Green River 

Formation as used by Dane (1955) in the southwestern 

part of the Uinta Basin, Utah. These rocks were 

described and sampled by the author and W. B. 

Cashion in 1969 (unpub. data) at two localities (fig. 1) 

near Utah Highway 33 in the vicinity of the divide 

between the Price River drainage to the southeast and 

the Strawberry River drainage to the north, about 25 

miles (40 km) southwest of the village of Duchesne. In 

this area, the Parachute Creek Member forms a belt of 

outcropping rocks several miles wide that dip 2° - 4 ° 

NE. beneath younger Eocene rocks into the Uinta 

Basin. The member forms a moderately rugged 

topography of steep shaly slopes and thin laterally 

persistent ledges of resistant oil shale. 

The composite section of rocks exposed at the two 

localities is 416 feet (126.8 m) thick (fig. 2). At the base 

is an asphaltic sandstone which forms the uppermost 

part of the delta facies of Bradley (1931). The top of 

1 
2 TRIOCTAHEDRAL SMECTITE IN THE GREEN RIVER FORMATION, UTAH 

R.10 E. 

FIGURE !.- Localities of composite measured section in southwest Duchesne County, Utah. Localities photographed in 

figures 3, 4, and 5 are shown by <. Base from U.S. Geological Survey Gray Head Park and Jones Hollow topographic quadrangles, scale 1:24,000, 1969 and 1968. 
GEOLOGIC SETTING 

Se- Fm. Member 

Cum_ulative thickness, Thickness 

ries in feet (and metres) Feet Metres 

Lithologic descr iption 

i!) 1. 7 0.52 Tuff Q) -". L!) 6.6 2 .01 Oil sh ale 

'5 Q) Ol 400 Q) 2 .0 0.61 Limest one 

0 u Q)- (121.9 2) 4 .3 1.31 Clayst one 

Q) Q) c 11.5 3 .51 Limestone and c laystone, interbedded "' c .., 0 6.0 1.83 Claystone 0 ::J 

N .<::: 1.6 0.49 Limestone u ~ 

... ~ Q) 13.3 4.05 Clay stone ... .0 ::J "' E 1.2 0 .37 Oil shale I- c.. Q) 12.0 3 .66 Claystone 

~ 3.4 1.04 Oil shale and c laystone 

350 0 .8 0 .24 Oil shale 

(1 06.68) 8 .4 2 .56 Dolomite, silt stone, and claystone 

5.4 1.65 Mostly c laystone 

8.4 2.56 Siltstone and c laystone 

9 .0 2 .74 Claystone 

1.0 0 .30 Dolomite 

17.0 5.18 Claystone 

5.2 1.59 Mostly oil shale; several thin t uffs 

18.6 5.67 Siltstone and claystone, interbedded 

300 12.8 3.90 Claystone and marlstone 

(91.44) 4.8 1.46 Oil sh ale 

4.9 1 .49 Claystone and marlstone 

4.8 1.46 Oil shale 

0 .2 0 .06 Tuff 

5.3 1.62 Marlstone and claystone 

0.5 0.15 Oil shale T 10.0 3.05 Marlstone 

4.9 1.49 Oil shale@ 

i!) 2.4 0 . 73 Marlst one L!) 250 4.0 1.22 Claystone Ol (76.20) 0 . 7 0 .21 Oil sh ale 

Q)- 8.4 2 .56 Claystone c c 0.02 0.006 Tuff .Q "' .., 12.0 3.66 Claystone 0 "' 3 .8 1.16 Claystone, marlstone, and oil shale UJ E ~ 6 .6 2 .01 Siltstone; 0.3 f t (9.1 em) tuff in middle 0 Q) 

z .0 4.3 1.31 Claystone UJ u.. E 5.9 1.80 Sil t st one, claystone and oil shale ~ Q) 

u Q) 

~ 8.6 2.62 Claystone .2: 200 0 a: -". (60.96) 0 .8 0 .24 Oil shale 

UJ Q) 2.3 0.70 Marlstone c Q) 

Q) u 2.0 0.61 Claystone 

~ 0.8 0.24 Tuff (.9 e 10.7 3.26 Claystone ::J 

.<::: 2.5 0 .76 Limestone u 2 .5 0.76 Con cealed ~ 

"' 10.9 3.32 Siltst one c.. 5.1 1.55 Si lt stone, dolomite, and clay stone 

150 7.0 2 .13 Claystone 

(45.72) 0 .2 0.061 Tuff 

7.0 2.13 Claystone 

0. 1 0.031 T u ff 

3 .3 1.01 Clayst one 

4 .8 1.46 Dolomite and limestone 

9.4 2.87 Claystone 

0 .8 0.24 Oil sh ale 

0.1 0 .. 031 Tuff 

100 20.0 6 .10 Claystone 

0.6 0 . 18 Tuff 

(30.48) 0 .3 0 .091 Oil shale 

5. 0 1.52 Dolomite, crayey 

8 .6 2.62 Claystone 

0.3 0.091 Tuff 

6.2 1.89 Claystone, marlstone, and oil shale 

1.3 0.40 Claystone and oil shale 

5 .5 1.68 Siltstone 

16.0 4 .8 8 Dolomite, clayey 

50 0 .7 0.21 Oil shale 

(15.24) 2 .2 0 .67 Dolomite and marlstone 

4 .6 1.40 Claystone 

1.0 0.30 O i l shale 

4.1 1.25 Dolomite; 0 .1 ft (3.0 em) tuff in middle 

2 .0 0.61 C laystone 

5.7 1.74 Limestone, clayey 

0.1 0 .031 Oil shale 

16.8 5.12 Dolomit e 

2.0 0.61 Siltstone, asph altic 

0 Delta faci es 6 .7+ 2.04 + Sandstone, asphaltic 

of Bradley 

(1931) 

FIGURE 2.-Composite measured section of part of the Green River Formation. Units 1-28 were measured in a roadcut along 

Utah Highway 33 near the top of the divide between the drainages of Willow Creek and Left Fork Indian Canyon in the 

NE1/4SW1/4 sec. 12, T. 11 S., R. 10 E., Duchesne County, Utah. Units 29-118 were measured near South Fork Avintaquin 

Creek in sec. 27, T. 6 S., R. 8 W., Duchesne County. The section was measured and described by J. R. Dyni and W. B. 

Cashion in 1969 (unpub. data). The circled numbers indicate the units that were studied during the present investigation. 

3 
4 TRIOCTAHEDRAL SMECTITE IN THE; GREEN RIVER FORMATION, UTAH 

the section is a bed of volcanic tuff, 1.7 feet (0.52 m) 

thick, which is the basal unit of the tuff zone of the 

Parachute Creek Member (Dane, 1955). The 

composite section of rocks consists of claystone and 

marlstone in beds commonly 2-20 feet (0.6-6.1 m) 

thick; scattered siltstone beds of similar thickness; 

limestone and dolomite, especially in the lower 55 feet 

(16.8 m) of the section; and scattered thin ledge-forming beds of dark oil shale commonly a few tenths of a 

foot to a few feet thick. Throughout the section are 

many thin beds of orange-weathering tuff. The rocks 

exposed at the two localities are shown in figures 3-5. 

METHOD OF INVESTIGATION 

Seventeen fist-size samples of selected beds of oil 

shale and claystone collected at the two localities 

shown in figure 1 were prepared for X-ray-diffraction 

analysis as follows: One-half of the sample was ground 

to minus-60 mesh in a hammermill. A 5-g (gram) 

portion of this material was pelletized at 20,000 lbjin2 

(pounds per square inch) in a hydraulic press and 

analyzed by conventional X-ray-diffraction methods. 

Another 15-g portion was prepared for clay-mineral 

analysis of the <2-pm (micrometre) fraction by the 

methods of Jackson (1973), which were modified as 

necessary to shorten sample preparation time. The 

<2-~Am fraction of each sample was treated in several 

ways to obtain specimens that were (1) magnesium 

saturated, (2) magnesium saturated and glycolated, 

(3) potassium saturated, and (4) potassium saturated 

and heated at 525°C. X-ray-diffraction traces were 

made of these specimens oriented on glass slides and 

of randomly oriented magnesium-saturated speciFIGURE 3.-Units 3-18 exposed in roadcut along the south side of 

Utah Highway 33 in sec. 12, T. 11 S., R. 10 E., Duchesne County, 

Utah. Units measured here but not shown in the photograph are 

equally well exposed in the same roadcut. 

FIGURE 4.-Exposures of units 24-71 on the north side of an 

unnamed valley tributary to South Fork Avintaquin Creek in 

sec. 27, T. 6 S., R. 8 W., Duchesne County, Utah. Most of the 

thin laterally persistent dark ledges are oil shale. 

FIGURE 5.-Exposures of units 54-118 on the north side of an 

unnamed valley tributary to South Fork A vintaquin Creek in 

sec. 27, T. 6 S., R. 8 W., Duchesne County, Utah. Most of the 

thin laterally persistent dark ledges are oil shale. 

mens. The <2-~-tm fraction of sample 17 was 

additionally tested for trioctahedral smectite by the 

method of Greene-Kelly (described by MacEwan, in 

Brown, 1961, p. 190) and was semiquantitatively 

analyzed for major elements by X-ray spectrometer. 

The instrumental conditions for X-ray diffraction 

were nickel-filtered CuKa radiation generated at 34 

kilovolts and 18 milliamperes with 1° scatter and 

divergence slits, 0.010-inch receiving slit, a 20 scan 

speed of 2° per minute, scintillation detector, and a 

counting rate of 3,000 counts per second. 
MINERALOGY 5 

TABLE !.-Qualitative mineralogy of oil-shale and claystone samples from Duchesne County, Utah 

[A, abundant; X, moderate to small amount; Tr., trace;?, doubtfully present; ... , absent) 

Sample 

No. 

Clay minerals 

(determined in 2-~m fraction) 

Smectite-to-illite 

ratio 

Method A Method B 

Chlorite 

Mixed 

layer Quartz 

Other minerals 

(determined in whole-rock fraction) 

Potassium 

feldspar 

Sodium 

feldspar Analcime 

Dolomite-to-calcite 

ratio 

Oil shale 

7 ..... 85 15 86 

13 ..... 89 11 92 

17 ..... 80 20 96 

27 ..... 84 16 87 

49 ..... 91 9 91 

63 ..... 79 21 79 

68 ..... 80 20 74 

80 ..... 82 18 80 

104 ..... 86 14 76 

14 A X 

8 

4 xi A X 

A X 

13 A X 

9 A X 

21 A X 

26 A X 

20 A X 

24 A X 

? 

X 

X 

X 

X 

80 

50 

55 

21 

28 

14 

21 

22 

62 

20 

50 

45 

79 

72 

86 

79 

78 

38 

Claystone 

9 ..... 77 23 92 8 

15 ..... 96 4 96 4 

25 ..... 79 21 90 10 

37 ..... 87 13 88 12 

60 ..... 89 11 90 10 

64 ..... 79 21 92 8 

95A .... 95 5 92 8 

109 ..... 81 19 90 10 

1 Mixed-layer clay computed with smectite and illite. 

2 Chlorite computed with smectite. 

MINERALOGY 

X' x' 

? 

The X-ray mineralogy of the 17 samples of oil shale 

and claystone is summarized in table 1. The clay 

minerals were determined in the < 2-~Jm fraction, 

whereas the remaining minerals were determined 

from X-ray-diffraction analyses of the whole-rock 

sample. 

CLAY MINERALS 

Trioctahedral smectite and illite are the principal 

clay minerals found in both rock types. Figures 6 and 7 

show X-ray -diffraction patterns of the < 2-I-'m fraction 

of typical samples of oil shale and claystone which 

were magnesium saturated, magnesium saturated and 

glycolated, potassium saturated, and potassium 

saturated and heated to 525°C. The smectites in both 

rock types behave similarly with various treatments; 

the basal 001 reflection of magnesium-saturated 

specimens expands from 14 A to 17 A on glycolation, 

and the potassium-saturated specimens show a 001 

reflection at 12.1-12.6 A, which collapses to about 10 

A on heating to 525°C. 

Applying the method of Reynolds and Hower (1970), 

the smectite was found to contain expandable 17 A 

layers ranging from 70 percent to usually in excess of 

A X 

A 

A X 

A X 

A Tr. 

A Tr. 

A X 

A X 

X 

Tr. 

X 

X 

Tr. 

Tr. 

Tr. 

X 

X 27 73 

100 0 

80 20 

89 f1 

73 27 

72 28 

100 0 

72 28 

85 percent. 1 The smectite in most samples shows 

good crystallinity, judging from the sharpness of the 

001 reflection. 

The smectite was determined to be trioctahedral by 

its 060 reflection, which is close to 1.53 A in most 

samples (figs. 6, 7, and lower pattern of fig. 8), and by 

reexpansion of the basal 001 spacing to 17 A after 

heating and glycolation of a lithium-saturated 

specimen (fig. 8, upper pattern). This technique 

(Greene-Kelly, 1953) shows that lithium-saturated 

trioctahedral smectites and beidellite will reexpand to 

17 A on glycolation after they have been heated 

between 200° and 300°C; lithium-saturated dioctahedral montmorillonites collapse irreversibly on 

heating and will not reexpand on glycolation. The 

trioctahedral smectites of this study are distinguished 

from beidellite by the 060 reflection; for beidellite, this 

reflection has a spacing of about 1.49 -1.50 A. 

The species of trioctahedral smectite in the samples 

studied could not be determined from the X-ray data 

alone. The diffraction pattern of an unoriented 

composite specimen of the < 2-~Jm fraction free of 

nonclay impurities, which was prepared from oil-shale 

lin table 3 of Reynolds and Hower (1970, p. 34), the d spacing for the 003 reflection for 

100-percent expandable 17 A layers in the randomly stratified in the 1M-ordered 

columns should read 5.67 A instead of 5.61 A, according to J. B. Hayes, Marathon Oil 

Co. (oral commun., 1973). 
6 

70 

TRIOCTAHEDRAL SMECTITE IN THE GREEN RIVER FORMATION, UTAH 

EXPLANATION 

S, smectite 

I, illite 

Q, quartz 

F, feldspar 

Intensity 

(counts per second) 

[600 

l300 

Potassium saturated and 

heated at 525° C; oriented 

Magnesium saturated, 

glycolated; oriented 

Magnesium saturated; oriented 

0 Magnesium saturated; 

random orientation 

s 06,33 

1.53 A 

\Q 

60 40 

Degrees 2(J 

Q 

Q 

Q 

s 003 

Q 

20 

FIGURE 6.-X-ray diffraction patterns of 2-~J.m fraction of oil-shale sample 49 treated in several ways. 

10.0A 

14.5 A 

s 001 

14.3A 

2 
70 

EXPLANATION 

S, smectite 

I, illite 

Q, quartz 

D, dolomite 

F, feldspar 

Intensity 

(counts per second) 

MINERALOGY 

S003/1003 

-3.29 A'. 

Potassium saturated and 

heated at 525°C; oriented 

s 005/1005 

1.99 A 

Q 

Q 

S003 

3.1 A± 

Potassium saturated; oriented 

Magnesium saturated, 

glycolated; oriented 

s 006? 

2.79A 

D? 

s 005 

Q 

Q 

Q 

[600 

[ 300 

0 Magnesium saturated; 

random orientation 

60 40 

Degrees 28 

S002/1002 

1002 

s 003 

s 004 

S003 

20 

-17.0 A 

S002 

8.4A 

1001 

I 001 

soov 14.2A 

s 001 

14.2 A 

FIGURE 7.- X-ray diffraction patterns of <2-J..tm fraction of claystone sample 64 treated in several ways. 

7 

2 
8 TRIOCTAHEDRAL SMECTITE IN THE GREEN RIVER FORMATION, UTAH 

Sample 17 

s 001 

17.0 A 

EXPLANATION 

S, smectite 

I, illite 

Lithium saturated, glycolated, and 

heated at 250°C; oriented 

Intensity 

(counts per second) 

Intensity measured on 

log scale (not shown) 

S005/1003 

S006 

[ 

600 

300 

0 

Composite of samples 13, 17, 27, and 49 

Sodium saturated; random orientation 

27.6A 

001 23.2 A\ 

12.6 A._30.5 \\ 

06,33 

15,24,31 

70 60 40 20 2 

Degrees 2(} 

FIGURE 8.-X-ray diffraction patterns of purified <2-jJm clay fractions of several oil-shale samples. 

samples 13, 17, 27, and 49, is shown in figure 8 (lower 

pattern). Several low-angle reflections at 3°-5° 26 

suggest some mixed-layer clay. The X-ray pattern 

resembles in a general way some patterns for highmagnesium- and low-aluminum-bearing trioctahedral 

smectites (hectorite and stevensite) reported by 

Faust, Hathaway, and Millot (1959). The low-angle 

reflections just mentioned suggest the possible 

presence of stevensite; however, the d spacings for 

the 060 reflections published by the aforementioned 

authors are consistently lower (1.52 A) than for the 

smectites reported here (1.53 A). According to X-ray 

data given by MacEwan (in Brown, 1961, p. 192) for 

some trioctahedral smectites, other possibilities 

include aluminous and iron-rich saponite. The 

possibility of more than one species of trioctahedral 

smectite cannot be ruled out as suggested by the 

broadness (multiple peaks?) of the 02 reflection in 

many X-ray patterns. (See the patterns for the 

unoriented magnesium-saturated specimens in figs. 6 

and 7.) 

A chemical analysis of a partly purified 

sodium-saturated specimen of the <2-J.tm fraction of 

oil-shale sample 17 is given in table 2, and an emission 

spectrographic analysis of a portion of the same 

specimen is given in table 3. 

Assuming that all of the K20 (potassium oxide) in 

the chemical analysis of sample 17 is in mixed-layer 

and discrete illite, and assuming an average 

composition of illite as determined by Weaver and 

Pollard (1973, table 3, p. 9), about 20 percent of the 

chemically analyzed specimen is illite and the 

remainder is trioctahedral smectite and probably 

some silicate impurities. (See ratios of smectite to 

illite for sample 17 in table 1.) 

The amounts of silica, lithium oxide, and fluoride in 

the calculated chemical composition of the illite-free 

smectite (table 2, rightmost col.) are close to the 

values reported for these constituents in stevensite by 

Bradley and Fahey (1962, table 1). However, the 

amounts of iron oxide and alumina reported here are 

considerably higher than the amounts found by 

Bradley and Fahey. 

A structural formula for the smectite calculated 

from the data in table 2 (rightmost col.) gave 

~.43 -0.04 -0.47 +0.47 

[(Alo.21Fe!.~1 Mg2.oaZno.o1Lio.o6HSia.96Alo.04 )010 (0H,F)2] (Nao.45Cao.ol) • 

2.57 
MINERALOGY 9 

TABLE 2.-Chemical analysis of a partly purified sodiumsaturated specimen of the< 2- JAm fraction of oil-shale sample 17 

[Chemical analysis by Wayne Mountjoy, Violet Merritt, Johnnie Gardner, and G.T. 

Oxide 

Si02 ............ . AhOa ........... . Total Fe as Fe 20 a .. MgO ............. . CaO ............. . 

Na20 ............ . K20 ............. . F ................ . ZnO ............. . 

Li20 ............. . CuO ............. . 

Loss on ignition ... . 

Burrow) 

Percent 

53.4 

7.5 

5.00 

15.5 

.17 

2.55 

1.38 

.85 

.09 

.14 

.02 

13.2 

Oxides fro~ first Calculated composition 

column assignable of smectite free of 

to illitel illite (percent) 

(percent) 

9.79 

5.18 

.98 

.54 

.06 

1.38 

1.69 

54.4 

2.9 

4.99 

18.7 

.14 

3.18 

1.06 

.11 

.17 

.02 

14.4 

Total........ 99.8 100.1 

lcomposition of illite is based on the average of chemical analyses of 24 illites 

calculated by Weaver and Pollard (1973, table 3, p. 9). 

TABLE 3.-Emission spectrographic analysis of a portion of the 

< 2- JAm fraction of oil-shale sample 17 

[Semiquantitative six-step spectrographic analysis by Nancy M. Conklin) 

Element Percent 

Si .......... 10 

AI .......... 5 

Fe ......... 3 

Mg ......... 10 

Ca......... .15 

Na ......... 3 

K .......... 3 

Ti.......... .1 

Element 

Parts per 

million 

Zn ........... 700 

Li .......... 1,500 

Cu ........... 150 

Mn .......... 70 

Ag.. .. .. .. . . . 1 

B ............ 150 

Ba ........... 70 

Be........... 1 

Co ........... 10 

Cr ........... 70 

Element 

Parts per 

million 

Ni ........... 20 

Pb ........... 70 

Sc........... 7 

Sr ........... 70 

v ............ 150 

Y ............ 10 

Zr ........... 30 

Ga ........... 20 

Yb........... 1 

NOTE.-Looked for, but not found: As, Au, Bi Cd, La, Mo, Nb, Pd, Pt. Sb, Sn, Te, 

U, W, P, Ce, Ge, Hf, In, Re, Ta, Th, Tl, Eu. 

Because of the likelihood of impurities in the 

smectite and because of the lack of data for ferric and 

ferrous iron, the preceding formula should be treated 

circumspectly. Despite these limitations, the formula 

shows that the amount of aluminum substitution in the 

tetrahedral sheet is small and that occupancy of cation 

sites in the octahedral sheet is low. If these 

relationships are true, they indicate a stevensitehectorite smectite rather than a saponite, which has 

considerably more aluminum substituting for silicon in 

the tetrahedral sheet and, consequently, also has a 

higher negative tetrahedral charge of about 0.25 to 

0.85 (fig. 9). Saponite also differs from stevensite and 

hectorite by generally having a positive octahedral 

charge and a cation occupancy of the octahedral sheet 

close to 3.00. The occupancy of the octahedral sites as 

shown by the formula seems unusually low, although -a 

value as low as 2.30 for a zincian trioctahedral 

smectite (sauconite) was reported by Weaver and 

Pollard (1973, table 40, analysis 3). 

.:7' 

&o.7 

q;.; 

~ 

J'o.s 

.....,; 

"< Q~ 0.5 

:t 

~o..."< 0.4 

ou 

0.3 

• 

Q 0.3 • 

().A 

-y~ 0.4 

~ ~ 0.5 

(" 

~ 0.6 

"9~ 

~ 0.7 

s 

0 

.. 

• 

• 

" <Y 

.... 

• 

EXPLANATION 

• Stevensite 

o Hectorite 

• Saponite 

't' Sauconite 

FIGURE 9.-Distribution of structural charge for some trioctahedral smectites. The data were compiled from published 

analyses. 1, Stevensite of Bradley and Fahey (1962); 2, 

smectite of this report. 

Faust, Hathaway, and Millot (1959) have shown that 

stevensite and hectorite are closely related species of 

trioctahedral smectite but that they differ in chemical 

composition, in structural charge, and in other 

properties. Stevensite is essentially a magnesium 

silicate and has a low negative layer charge owing to a 

small deficiency of divalent octahedral cations. 

Hectorite is similar in composition to stevensite, but it 

also contains essential amounts of lithium, aluminum, 

and fluorine. Hectorite has a larger negative layer 

charge than stevensite because of substitution of 

lithium for divalent octahedral cations and because of 

a deficiency of octahedral cations as in stevensite (fig. 

9). The distinction between the two minerals becomes 

less clear when the occurrence of stevensite in the 
10 TRIOCTAHEDRAL SMECTITE IN THE GREEN RIVER FORMATION, UTAH 

Green River Formation reported by Bradley and 

Fahey (1962) is considered. This smectite contains 

appreciable aluminum, lithium, and fluorine, like 

hectorite, but it has a structural layer charge of only 

-0.06, which is typical of stevensite. The relatively 

high layer charge (-0.47) for the smectite of this 

study, as well as the presence of lithium, aluminum, 

and fluorine, suggest closer affinities to hectorite than 

to stevensite. It is concluded, therefore, that the 

smectite of this study is probably a hectorite. 

The nonexpandable layer clay mineral having a 

basal 001 spacing of 10 A is identified here as illite. 

The few broad reflections suggest that most of this 

material is illite in the sense of Hower and Mowatt 

( 1966), but some of it may be a true mica, possibly 

biotite, which is commonly found in many of the thin 

beds of volcanic tuff scattered through the composite 

measured section ( J. R. Dyni, unpub. data, 1972). 

The relative abundance of illite to smectite was 

determined in two ways. In the first method (table 1, 

method A) the ratio of the relative intensity of the 001 

reflection of 100-percent illite to 100-percent smectite 

in the glycolated magnesium -saturated specimens was 

assumed to be 1:4.5. A similar ratio was used 

indirectly by Schultz (1964, p. C11) to calculate the 

proportions of aluminous illite and aluminous montmorillonite in the Pierre Shale. A similar 001 

peak-height ratio was found in X-ray-diffraction 

analysis of some synthetic mixtures of illite, montmorillonite, and kaolinite by Jarvis, Dragsdorf, and 

Ellis (1957, fig. 1). In the second method (table 1, 

method B), adopted from Droste (1961, p. 13, 15), the 

intensity of the 001 reflection of illite at 10 A is 

assumed to remain unchanged after heating to 525°C. 

(Droste heated his samples to 400°C.) The intensity of 

the reflection at 10 A is assumed to increase in 

proportion to the amount of smectite present when its 

crystal structure collapses to a basal spacing of about 

10 A on heating. The percentage of illite is calculated 

from the ratio of the area of the 10 A reflection of the 

glycolated specimen (which provides maximum 

separation of the 001 reflections of illite and smectite) 

to the area of the same reflection after heating to 

525°C multiplied by 100. In both methods smectite 

was calculated as the difference between 100 percent 

and the calculated percentage of illite. The results 

(table 1) show the preponderance of smectite, 

commonly 80 percent or more, in the clay mineral 

fraction in most samples. 

Mixed-layer clay was detected in a few samples. 

Because the mixed-layer clay collapsed to 10 A on 

heating to 525°C, all of it can be assumed to be 

mixed-layer illite-smectite. Chlorite was noted in one 

sample. Kaolinite was not detected in any of the 

samples. 

OTHER MINERALS 

Quartz is relatively abundant in all of the samples. 

Potassium feldspar and, in lesser amounts, sodium 

feldspar are present in small to trace amounts in many 

of the samples. Analcime was detected in two 

samples. 

Dolomite and calcite are major mineral components 

of the oil shales and claystones. Their relative 

abundance to each other was calculated by the method 

of Royse, Wadell, and Petersen (1971) by using peak 

heights as measured on the diffraction trace rather 

than by fixed time. Calcite is relatively more abundant 

in the oil shales than in the claystones; in five of nine 

samples of oil shale, calcite exceeds dolomite in 

abundance. Conversely, dolomite is more abundant in 

the claystones than in the oil shales; in all but one 

sample of claystone, dolomite greatly exceeds calcite 

in abundance. 

ORIGIN OF SMECTITE 

Trioctahedral smectite, which is considered to be 

sparse in sedimentary rocks (Weaver, 1967, p. 43), 

may be more abundant in sediments of continental 

closed basins than has been previously suspected. 

Papke (1970, 1972) described playa deposits of 

saponite at Ash Meadows, Nev., and sepiolite and 

associated saponite in Amargosa Desert, southern 

Nevada. Droste (1961) found smectite and illite to be 

the principal clay minerals in sediments from many 

playa lakes in the Mojave Desert, southern California. 

Although Droste (1961, p. 15) noted the presence of 

both dioctahedral and trioctahedral smectite, he did 

not distinguish between them but inferred that the 

latter type comprised a substantial part of the clay 

fraction at least in a few playas. Saponite in dry-lake 

sediments in western Australia was reported by 

Graham (1953), and hectorite from some Tertiary lake 

beds in eastern Morocco was described by Millot 

(1949) and Jeanette (1952). (Also see Faust, and 

others, 1959, p. 343.) 

In the Green River Formation, stevensite, first 

reported by Bradley and Fahey (1962), occurs in 

widely spaced thin layers through the saline facies of 

the Wilkins Peak Member in southwest Wyoming 

(Bradley and Eugster, 1969, p. B16). Tank (1969) 

reported abundant smectite and illite in oil shales and 

shales of the underlying Tipton Shale Member of the 

Green River Formation in the same area, but he did 

not distinguish between types of smectite. 

Considering these occurrences and the occurrences 

described in this report, trioctahedral smectite may be 

much more abundant in the formation than has been 

recognized. 

The trioctahedral smectite in the rocks studied may 
STRATIGRAPHIC MINERALOGY 11 

be authigenic. Magnesium-rich interstitial water, as 

evidenced by the presence of abundant (and probably 

authigenic) dolomite, may be an important factor in 

the origin of the smectite, as it seems to be for 

sepiolite and probably for associated saponites in a 

playa deposit described by Papke (1972, p. 213- 214). 

The simple clay-mineral assemblage of smectite and 

illite, with the virtual exclusion of other clay minerals, 

might suggest an authigenic origin, although lack of 

clay minerals can be explained several ways. 

Therefore, it would be of value to know whether the 

discrete illite is also trioctahedral, which, if it is, 

would suggest a common origin or precursor. 

If the smectite is allogenic, its origin is problematic 

inasmuch as large quantities of trioctahedral smectite 

in probable source rocks are not known. Cretaceous 

marine shales and younger rocks on the San Rafael 

Swell are likely source rocks, but these probably 

contained dioctahedral smectite and other clay 

minerals, as they do elsewhere in the Rocky Mountain 

region (Schultz, 1964, p. C6; Weaver, 1961). Volcanic 

ash is a probable source for some of the smectite; 

however, the ash beds present in the composite 

section amount to only 1 or 2 percent of the total 

sequence. Even if the entire hydrographic basin of the 

Tertiary lake occupying the Uintah Basin is 

considered, the total amount of ash that could have 

been contributed to the lake by streams, plus that 

deposited directly in the lake, probably would not 

amount to more than two or three times the amount of 

ash now present in the composite section. 

Unless a source area which contained unusually 

large amounts of trioctahedral smectite is found, it 

becomes necessary to consider the formation of the 

smectite by reactions with other minerals or possibly 

by transformation of dioctahedral to trioctahedral 

smectite. 

Levinson and Vian (1966) synthesized probable 

trioctahedral smectite by reacting dolomite, quartz, 

kaolinite, and water at moderate temperatures, and 

Graham (1967) subsequently proposed that saponite in 

a surficial playa deposit near Marchagee, Western 

Australia, was formed by this method at ambient 

temperature and pressure. Transformation of 

dioctahedral to trioctahedral smectite has not, to the 

author's knowledge, been demonstrated experimentally, but it would be worth trying. 

STRATIGRAPHIC MINERALOGY 

In Indian Canyon in the Uinta Basin, the sequence of 

rocks overlying unit 118 of the measured section in 

figure 2 to the base of the Horse Bench Sandstone Bed 

in the upper part of the Green River Formation is 324 

feet (98.8 m) thick and consists predominantly of 

lacustrine claystones, thin beds of oil shale, and 

associated rock types similar to those of the 

measured section. The X-ray mineralogy of the rocks 

in this 324-foot-thick (98.8-m-thick) sequence, similar 

to that of the measured section, consists of dolomite, 

calcite, feldspars, quartz, illite, and abundant 

smectite. The smectite is probably trioctahedral, but 

this was not confirmed by X-ray analysis. Minor 

amounts of other clay minerals are also present. 

The smectite in the entire 7 40-foot-thick 

(225.6-m-thick) sequence of rocks from the base of the 

measured section to the base of the Horse Bench 

Sandstone Bed can be divided, with few exceptions, 

into five distinct units, on based on the spacing of the 

001 reflection of the smectite, as follows: 

Feet (metres in parentheses) above 

base of total sequence 

Base of Horse Bench Sandstone Bed. 

Average spacing (A) 

of 001 reflection of 

smectite 

721--740(219.8--225.6) ................... 14.7 

540--721(164.6--219.8) ................... 12.6 

299--540 (91.1--164.6) ................... 14.7 

173--299 (52.7-- 91.1) ................... 12.6 

0--173 (0 -- 52.7) ................... 14.7 

The change in spacing in the basal reflection of 

smectite, if real, may reflect several episodic changes 

in the major interlayer cation vertically through the 

above sequence of rocks-that is, from calcium (?) 

smectite with a basal spacing of 14.7 A to sodium 

smectite with a spacing of 12.6 A. Possibly, this 

alternation in spacing may have been in response to 

changes in the salinity of the lake waters. As salinity 

increased, the dominant exchangeable cation became 

sodium, and as salinity decreased, calcium became the 

dominant cation. 

The sequence of rocks between the probable 

Mahogany oil-shale bed (units 80-81 of the measured 

section in fig. 2, according to W. B. Cashion, oral 

commun., 1971) and the base of the Horse Bench 

Sandstone Bed is 484 feet (147.5 m) thick in Indian 

Canyon and can be traced in the subsurface in oil and 

gas test wells eastward to the vicinity of Ouray, 

Utah. This sequence of rocks, which contains 

abundant smectite and illite in Indian Canyon, thins 

and grades laterally into a lithofacies composed 

entirely of oil shale that contains no smectite, little or 

no illite, and, locally, abundant nahcolite and shortite. 

The Horse Bench Sandstone Bed thins eastward and is 

absent in the Ouray area; however, its approximate 

position in wells can be determined from geophysical 

well logs. 

The same sequence of rocks in the Western Oil 

Shale Corp. core hole EX -1, in the SW1

/4SE1/4 sec. 

36, T. 9 S., R. 20 E., Uintah County, about 57 miles (92 

km) east of Indian Canyon, has thinned to 448 feet 
12 TRIOCTAHEDRAL SMECTITE IN THE GREEN RIVER FORMATION, UTAH 

(136.6 m) and lies between the depths of about 1,854 

and 2,302 feet (565.1 and 701.6 m). Smith, Trudell, and 

Robb (1972), who studied in detail the lithology and 

mineralogy of the core from this well, found that the 

sequence consists entirely of oil shale. They reported 

that throughout the sequence, as at Indian Canyon, 

dolomite, calcite, potassium feldspar, sodium feldspar, 

and quartz are abundant but, significantly, that 

smectite is absent and illite evidently is present only 

in the lower 250 feet (76.2 m) of the sequence. The last 

reported occurrence of illite upward in the sequence 

coincides roughly with the first appearance of 

nahcolite as in the Piceance Creek basin in Colorado 

(Hite and Dyni, 1967, fig. 4). Nahcolite becomes locally 

abundant in the nodules, masses, and thin beds in the 

upper 120 feet (36.6 m) of the sequence. Some shortite 

(Na2COa-2CaC03) and sparse neighborite NaMgF3) 

and searlesite (N aBSi 206 · H20) are also found in the 

nahcolite-bearing part of the sequence. The top of the 

nahcolite- and shortite-bearing oil shale extends 

several tens of feet higher than the sequence of rocks 

considered here. 

The eastward change from claystones and 

associated rocks to oil shale is reflected by increasing 

resistivities on electric logs of wells that penetrate 

these rocks (fig. 10). The predominantly claystone 

sequence in the vicinity of Indian Canyon shows a 

shale-like response on electric logs (Gulf 1 Indian 

Canyon well, in fig. 10), averaging about 20 ohms or 

less. The resistivity increases gradually eastward 

toward the Western Oil Shale Corp. core hole EX-1, 

and in the Sun 1 South Ouray weli, a few miles to the 

northwest, the average apparent resistivity of these 

rocks has increased to about 156 ohms. This increase 

in resistivity is attributed to decreasing clay mineral 

content with a corresponding increase in kerogen and 

carbonate minerals. 

The area of the oil shale and associated sodium 

minerals marks a chemical depocenter of Lake Uinta 

during Green River time, which is younger than 

nahcolite-bearing oil-shale deposits in the Piceance 

Creek basin in Colorado and older than another saline 

sequence of lacustrine rocks at the base of the Uinta 

Formation near Duchesne, Utah. 

Cook (1973) and Vine and Tourtelot (1969) have 

noted that the amounts of many of the trace elements 

found in oil shale from the Green River Formation are 

less than would be expected for an organic-rich 

sedimentary rock. On the other hand, a few elements, 

including lithium, beryllium, and fluorine, show a 

twofold to tenfold increase over crustal abundance. 

The distribution and abundance of some trace 

elements found in oil shale may be controlled in part 

by basin lithofacies and the geochemical conditions of 

>-

1-

w 

160 

> 120 

1-

(J)(J) 

(J)2 

~ 6 80 

1-z 

zw 

a: 

<( 

a.. 

a.. 

<( 

~ .:,t.<:t 0 . lL a: ... 

.r: en .~ 1.0 

a: . .... I-

..... a' ::J .... 

(.9 u 

Ql 

en 

10 20 30 40 

60 

50 Ml 

20 40 80 KM 

FIGURE 10.-Diagram showing the eastward increase of the 

averaged resistivity determined from the 16-inch normal curve 

for the sequence of Green River rocks between the Mahogany oilshale bed and the Horse Bench Sandstone Bed in 10 wells 

between Indian Canyon and Ouray, Utah. 

their depositional environments. As noted earlier, 

trioctahedral smectite contains notably large amounts 

of lithium, zinc, and copper. These elements, and 

others, may have been trapped during the formation 

and deposition of the smectite before they could 

migrate basinward into the oil-shale facies. This could 

explain why copper and zinc are found in quantities 

less than anticipated in the oil shale. For example, zinc 

in the whole-rock fraction of the 17 samples listed in 

table 1 ranges from 32 to 121 ppm (table 4), a threefold 

to ninefold increase in abundance over that of 

pyrolyzed Green River oil shale analyzed by Cook 

(1973). If smectite served as a chemical trap for 

selected metals, perhaps such elements could be 

TABLE 4.-Semiquantitative X-ray fluorescence analysis of zinc 

in whole-rock samples of oil shale and claystone 

[Analyses by J. R. Dyni) 

Oil Shale Claystone 

Zinc Zinc 

Sample No. (ppm) Sample No. (ppm) 

7 ................... 102 9 ................... 108 

13 ................... 38 15 ................... 32 

17 ................... 88 25 ................... 36 

27 ................... 75 37 ................... 55 

49 ................... 43 60 ................... 42 

63 ................... 71 64 ................... 54 

68 ................... 121 95A ................. 41 

80 ................... 59 109 ................... 76 

104 ................... 74 
REFERENCES CITED 13 

Environment Fluvial Near-shore lacustrine Offshore lacustrine Chemical depocenter 

Salinity of Fresh Fresh to moderately saline Saline Hypersaline sediment waters 

Eh Oxidizing Mildly reducing Moderately to Strongly reducing strongly reducing 

Rock type Variegated mudstone, Green claystone, some marlstone, Kerogenaceous marlstone Oil shale and 

siltstone, and drab sandstone and thin beds of oil shale and oil shale evaporites 

Clay minerals Various smectite, illite, mixed- Smectite (trioctahedrall Illite Little illite or 

layer chlorite and kaolinite and illite no clay minerals 

---

Principal authigenic Calcite(?) 

Mixed dolomite 

Dolomite Dolomite, dawsonite 

matrix minerals and calcite and quartz 

FIGURE 11.-Schematic cross section of rock types and associated clay and authigenic matrix minerals found in the Green River 

Formation and related rocks, Uinta and Piceance Creek basins, Utah and Colorado. 

concentrated in economic amounts. In this regard, 

there are a number of units of high electrical 

conductivity in rocks above and below the Mahogany 

bed in several wells between Indian Canyon and 

Ouray. For example, in the Shamrock 2 Walton well, 

in the NW1

/4NE1/4 sec. 14, T. 9 S., R. 16 E., Duchesne 

County, several such conductive zones are present 

between the depths of 2,420 and 3,130 feet (737 .6 and 

954.0 m). The top of the Mahogany bed in this well is 

at a depth of 2, 769 feet (844.0 m). Perhaps these high 

conductivities are attributable to metal-bearing 

smectites or possibly to sulfide minerals, although 

sulfide minerals did not seem especially abundant in a 

few samples of rotary cuttings of one conductive unit 

that were examined. 

BASIN LITHOFACIES 

Regardless of the process responsible for the large 

quantities of trioctahedral smectite in the Green River 

Formation, the fact remains that this study, together 

with other published data, suggests a zonation of clay 

minerals from basin edge to center (fig. 11). The clay 

facies shown in figure 11 are not necessarily 

synchronous; the cross section simply shows their 

relative positions in the basin as they are now known. 

REFERENCES CITED 

Bradley, W. H., 1931, Origin and microfossils of the oil shale of the 

Green River formation of Colorado and Utah: U.S. Geol. 

Survey Prof. Paper 168, 58 p. 

Bradley, W. H., and Eugster, H. P., 1969, Geochemistry and paleolimnology of the trona deposits and associated authigenic 

minerals of the Green River Formation of Wyoming: U.S. 

Geol. Survey Prof. Paper 496-B, 71 p. 

Bradley, W. H., and Fahey, J. J., 1962, Occurrence of stevensite in 

the Green River Formation of Wyoming: Am. Mineralogist, 

v. 47, nos. 7-8, p. 996-998. 

Brown, G., 1961, The X-ray identification and crystal structures of 

clay minerals [2d ed.]: London, Mineralog. Soc. 544 p. 

Cook, E. W ., 1973, Elemental abundances in Green River oil shale: 

Chemical Geology, v. 11, p. 321-324. 

Dane, C. H., 1955, Stratigraphic and facies relationships of the 

upper part of the Green River Formation and the lower part of 

the Uinta Formation in Duchesne, Uintah, and Wasatch 

Counties, Utah: U.S. Geol. Survey Oil and Gas Inv. Chart 

OC-52. 

Droste, J. B., 1961, Clay minerals in the playa sediments of the 

Mojave Desert, California: California Div. Mines Spec. Rept. 

69, 19 p. 

Faust, G. T., Hathaway, J. C., and Millot, Georges, 1959, A 

restudy of stevensite and allied minerals: Am. Mineralogist, v. 

44, nos. 3-4, p. 342-370. 

Graham, J ., 1953, An examination of clays from Marchagee and 

Cardabia, Western Australia: Royal Soc. Western Australia 

Joun., v. 37, p 91-95. 

Graham, J., 1967, Formation of saponite from kaolinite, quartz and 

dolomite: Am. Mineralogist, v. 52, p. 1560-1561. 

Greene-Kelly, R., 1953, The identification of montmorillonoids in 

clays: Soil Sci. Jour. (London), p. 233-237. 

Hite, R. J., and Dyni, J. R., 1967, Potential resources of dawsonite 

and nahcolite in the Piceance Creek basin, northwest 

Colorado: Colorado School Mines Quart., v. 62, no. 3, p. 25-38. 

Hosterman, J. W., and Dyni, J. R., 1972, Clay mineralogy of the 

Green River Formation, Piceance Creek basin- A preliminary study, in Geological Survey research 1972: U.S. Geol. 

Survey Prof. Paper 800-D, p. D159-D163. 

Hower, John, and Mowatt, T. C., 1966, The mineralogy of illites 

and mixed-layer illite/montmorillonites: Am. Mineralogist, v. 

51, nos. 5-6, p. 825-854. 

Jackson, M. L., 1973, Soil chemical analysis-Advanced course 

[2d ed.]: pub. by the author, Madison, Wisconsin Univ., Dept. 

Soil Sci., 894 p. 

Jarvis, N. L., Dragsdorf, R. D., and Ellis, Roscoe, Jr., 1957, 

Quantitative determination of clay mineral mixtures by X-ray 

diffraction: Soil Sci. Soc. America Proc., v. 21, p. 257- 260. 
14 TRIOCTAHEDRAL SMECTITE IN THE GREEN RIVER FORMATION, UTAH 

Jeanette, Andrew-Pierre, 1952, Argiles smectiques et Rhassoul, in 

Geologies des Gites Mineraux Monocains: Internat. Geol. 

Cong., 19th, Algiers, 1952, Regional Mon. Ser. 3, Monoc no. 1, 

p. 371-382. 

Levinson, A. A., and Vian, R. W., 1966, The hydrothermal 

synthesis of montmorillonite group minerals from kaolinite, 

quartz, and various carbonates: Am. Mineralogist, v. 51, no. 

3- 4, p. 495-498. 

Millot, Georges, 1949, Relations entre la constitution et Ia genese 

des roches sedimentaires argileuse: Geol. app. et prospection 

miniere, Nancy, v. 11, p. 199-201. 

Papke, K. G., 1970, Montmorillonite, bentonite, and fuller's earth 

deposits in Nevada: Nevada Bur. Mines Bull. 76, 47 p. 

__ 1972, A sepiolite-rich playa deposit in southern Nevada: 

Clays and Clay Minerals, v. 20, no. 4, p. 211-215. 

Reynolds, R. C., Jr., and Hower, John, 1970, The nature of interlayering in mixed-layer illite-montmorillonites: Clays and Clay 

Minerals, v. 18, no. 1, p. 25-36. 

Royse, C. F., Jr., Wadell, J. S., and Petersen, L. E., 1971, X-ray 

determination of calcite-dolomite-An evaluation: Jour. Sed. 

Petrology, v. 41, no. 2, p. 483-488. 

Schultz, L. G., 1964, Quantitative interpretation of mineralogical 

composition from X-ray and chemical data for the Pierre 

Shale: U.S. Geol. Survey Prof. Paper 391-C, 31 p. 

Smith, J. W ., Trudell, L. G., and Robb, W. A., 1972, Oil yields and 

characteristics of Green River Formation oil shales at WOSCO 

EX -1, Uintah County, Utah: U.S. Bur. Mines Rept. lnv. 

7693, 145 p. 

Tank, Ronald, 1969, Clay mineral composition of the Tipton Shale 

Member of the Green River Formation (Eocene) of Wyoming: 

Jour. Sed. Petrology, v. 39, no. 4, p. 1593-1595. 

Vine, J.D., and Tourtelot, E. B., 1969, Geochemical investigations 

of some black shales and associated rocks: U.S. Geol. Survey 

Bull. 1314 -A, 34 p. 

Weaver, C. E.,1961, Clay mineralogy of the Late Cretaceous rocks 

of the Washakie Basin, in Wyoming Geol. Assoc. 16th Ann. 

Field Conf. Guidebook, Symposium on Late Cretaceous rocks 

of Wyoming: p. 148- 154. 

__ 1967, The significance of clay minerals in sediments, Chap. 

2, in Nagy, B., and Columbo, U., eds., Fundamental aspects of 

petroleum geochemistry: Amsterdam and New York, Elsevier 

Publishing Co., p. 37- 75. 

Weaver, C. E., and Pollard, L. D., 1973, The chemistry of clay 

minerals-Developments in sedimentology 15: New York, 

Elsevier Sci. Publishing Co., 213 p. 

,;,u.s. GOVERNMENT PRINTING OFFICE, 1976-677-340/77