Uranium and Diagenesis in Evaporitic Lacustrine 

Mudstone of the Oligocene White River Group, 

Dawes County, Nebraska 

U.S. GEOLOGICAL SURVEY BULLETIN 1956 
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Uranium and Diagenesis in Evaporitic Lacustrine 

Mudstone of the Oli ocene White River Group, 

Dawes County, Neb aska 

By KEN DELL A. DICKI NSO 

U.S. GEOLOGICAL SURVEY BULLE IN 1956 
U.S. DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, JR., Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

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Library of Congress Cataloging-in-Publication Data 

Dickinson, Kendell A., 1931-

Uranium and diagenesis in evaporitic lacustrine mudstone of the Oligocene 

White River Group, Dawes County, Nebraska I by Kendell A. Dickinson. 

p. em. - (U.S. Geological Survey bulletin ; 1956) 

Includes bibliographical references. 

Supt. of Docs. no.: I 19.3:1956 

1. Uranium ores-Nebraska-Dawes County. 2. Geology, 

Stratigraphic-Oligocene. 3. Geology-Nebraska-Dawes 

County. 4. Diagenesis-Nebraska-Dawes County. 5. White River 

Group. I. Title. II. Series. 

QE75.B9 no. 1956 

[QE390.2.U7] 

557.3 s-dc20 90-14109 

[553.4'932'0978293] CIP 
CONTENTS 

Abstract 1 

Introduction 1 

Acknowledgments 1 

Methods 2 

Geology 3 

Chadron Formation 3 

Brule Formation 4 

Facies and depositional environments 6 

Mineralogy 7 

Statistical analysis 7 

Diagenesis 8 

Uranium 12 

Summary 15 

References cited 16 

Appendix. Chemical and mineralogic data for samples of the White River Group, 

Dawes County, Nebr. 19 

FIGURES 

1. Geologic map of study area showing sample localities 2 

2. Chart of stratigraphy of the White River Group near Chadron, northwestern 

Nebraska 3 

3. Generalized stratigraphic section of the White River G~oup at Trunk Butte 3 

4. Photograph of the Chadron and Btule Formations at Trunk Butte 4 

5. Generalized stratigraphic section of the White River Gtoup at Noddings 

ridge 5 

6. Scanning electron micrograph of rounded clay clast in ~pper purplish white layer 

at Noddings ridge 6 

7. Photomicrograph of pelletal mudstone of the Orella M¢mber at Trunk Butte 6 

8. Generalized stratigraphic section of playa facies of the :Orella Member near 

Isinglass Buttes 7 · 

9. Photograph of bedded granular gypsum in evaporite fa¢ies of the Orella Member 

at Noddings ridge 7 

10. Photograph of mudcrack impressions in shallow-water ~acustrine limestone at 

Trunk Butte 8 · 

11. Photomicrographs of a thin section of limestone from t~e uppermost limestone 

bed in the Orella Member, south end of Noddings ridge 9 

12. Scanning electron micrographs of volcanic ash altered to montmorillonite in 

channel facies of Orella Member at Noddings ridge 13 

13. Scanning electron micrograph of detrital clay from upper purplish white layer at 

Noddings ridge 13 

14. Scatterplots showing relation between illite and smectite X-ray diffraction 

data 14 

Contents Ill 
15. Photomicrograph showing fibrous gypsum and chalcedony in vein in the Orella 

Member at Noddings ridge 15 

16. Photomicrograph of thin section of fibrous gypsum 15 

17. Photomicrograph of thin section of calcareous mudstone from Noddings 

ridge area 16 

18. Scanning electron micrographs of siliceous veins in limestone in uppermost part 

of the Orella Member 17 

19. Scanning electron micrograph of air-fall volcanic ash (upper Whitney ash) from 

Round Top area 18 

TABLES 

1. Location of X-ray diffractogram peaks measured for the White River Group 

samples 2 

2. Correlation coefficient matrix of log10-transformed data 10 

3. Varimax factor analysis for five factors: rotated factor loadings 12 

IV Contents 
Uranium and Diagenesis in Evapori~ic Lacustrin.e 

Mudstone of the Oligocene White ~iver Group, 

Dawes County, Nebraska 

By Kendell A. Dickinson 

Abstract 

The Oligocene White River Group consists of the Chadron and the overlying Brule Formations in northwestern 

Nebraska. The Chadron Formation consists of alluvial and 

colluvial vitric mudstone beds, but in addition contains white 

persistent layers (purplish-white layers) that probably resulted 

from soil formation on vitric parent material. West of the 

current study area a basal sandstone facies of the Chadron is 

host rock for the Crow Butte uranium deposit. The Brule, 

which consists mostly of pedogenically altered alluvial and 

fluvial vitric mudstone deposits, contains a uraniferous lacustrine facies northwest of Chadron, Nebraska. 

Detrital minerals in rocks of the White River Group 

include quartz, feldspar, volcanic glass, smectite, and illite. 

Chemical precipitate minerals in the lacustrine facies are 

calcite, dolomite, and gypsum. Authigenic minerals include 

calcite, dolomite, gypsum, smectite, opal, chalcedony, 

together with oxidized uranium minerals. 

An R-mode factor analysis and a correlation coefficient 

matrix were calculated for a chemical and mineralogical data 

base from White River samples. A five-factor grouping is 

summarized as follows: Factor 1 contained a large group of 

variables with negative factor loadings that are believed to 

represent a predominantly detrital suite. This group contained 

AI, Fe, K, Ti, Na, Li, feldspar, smectite, Ba, Cu, Mg, and illite. 

Included in the same factor but opposite in sign are opal, Ca, 

and U. Uranium and silica were probably released during 

alteration of the ash. The silica apparently formed opal and 

eventually chalcedony. Factor 2 included gypsum, Sr, and 

dolomite representing the evaporitic facies of the lacustrine 

beds. Quartz and Si02 make up factor 3. Factor 4 contained 

Mg and V, and factor 5 contained P. 

Although vitric material in the mudstones partially 

altered to smectite, most of the clay material is believed to be 

detrital because it is included in factor 1 with the group of 

minerals and elements interpreted to be detrital and because 

most of the clay has a detrital texture. The purplish-white 

Manuscript approved for publication August 6, 1990. 

layers are high in smectite relative to illite, perhaps resulting 

from pedoger1tic diagenesis. 

INTRODijCTION 

A uratiium occurrence is present in a playa facies of 

the Brule F~rmation about 12 mi northeast of Chadron, 

Nebr. The $rule together with the underlying Chadron 

Formation c~nstitutes part of the Oligocene White River 

Group. The troup primarily comprises a nonmarine clastic 

sequence deposited by fluvial and pedogenic processes, but 

it also contailj1s lacustrine beds. The objectives of the present 

report are to $tudy the stratigraphic and diagenetic setting of 

the uranium i deposit at Noddings ridge, which was first 

reported by i Dunham (1955), about 12 mi northeast of 

Chadron, Ne~r. Noddings ridge is an informal name applied 

to the topographic ridge that extends southward from the 

White River through sees. 3, 10, and 15, T. 34 N., R. 47 W. 

Uranium is produced at an in-situ leaching pilot plant 

from the Orow Butte deposit in the basal Chadron 

Formation n~ar Crawford, in western Dawes County, Nebr., 

about 20 mi iwest of Chadron, Nebr. (Collings and Knode, 

1984; Gjels~een and Collings, 1988). The Crow Butte 

deposit is wqst of the areas studied in this report. 

Sampl~s of the White River Group were collected 

from three areas: Trunk Butte, Isinglass Buttes, and Noddings ridge (ng. 1). A chemical-mineralogical data base was 

assembled frbm these samples. 

ACKNOWLEDGMENTS 

Help f~r this report was received from several people 

and is grat¢fully acknowledged. Gary Skipp prepared 

oriented clay mineral mounts for the X-ray diffraction 

studies and o~erated the XRD machine. James Nishi helped 

with the sc~ning electron microscope. The chemical 

Acknowledgments 1 
43° 

K 

R 50 W 

Area of fig. 1 

NEBRASKA 

R 4B W 

5 

Ta 

R 47 W 

10 MILES 

R 45 W 

T 

34 

N 

T 

32 

N 

Figure 1. Geologic map of study area showing sample 

localities (x), Arikaree Group (Ta), White River Group (Tw), 

and Cretaceous (K). Geology from Burchett (1986). 

analyses were done in the analytical laboratories of the U.S. 

Geological Survey at Denver, Colo. D.M. McKown 

supervised the radiochemical analyses; J.E. Taggart 

supervised the X-ray spectroscopy; and D.E. Detra and L.R. 

Layman supervised optical spectroscopy. 

METHODS 

The data used for this report are given in an appendix 

(p. 19), which comprises analyses of 16 elements and 8 

minerals for 46 samples. Uranium and thorium contents 

were determined by the delayed-neutron method (Millard, 

1976). Oxides were determined by X-ray fluorescence, and 

other elemental values were determined by inductively 

coupled plasma spectroscopy (ICP) (Crock and others, 

1983). Mineralogical determinations were by X-ray 

diffraction of whole-rock cell mounts and oriented clay 

mineral mounts (XRD). Two sets of XRD data for smectite 

and illite are included in the appendix. One set, for the 

factor analysis and correlation coefficient matrix, was 

measured from the whole-rock X-ray diffractograms also 

used for dolomite, calcite, feldspar, quartz, opal, and 

gypsum. These data values are the areas in square inches of 

the appropriate XRD peaks (table 1). The whole-rock XRD 

data was obtained under conditions made as uniform as 

possible for all the XRD runs. The same mount preparation 

procedures, the same instrument, and the same instrument 

settings were used for all samples, and all the runs were 

Table 1. Location of X-ray diffractogram peaks (Cu, Ka 

radiation) measured for the White River Group samples 

(Dickinson, 1988) 

Mineral X-ray diffraction Crystallographic 

peak (degrees 28) indices 

Dolomite 31.0 104 

Calcite 29.4 104 

Feldspar 26.9-27.9 002 

Quartz 26.7 101 

Opal (C-T) 1 21.6 111 

Gypsum 11.7 020 

Illite2 8.8 001 

Smectite 5.9 001 

1

0pal that displays a cristobalite-tridymite pattern (Jones and 

Segnit, 1971). 

~e term "illite" is used for all minerals that contribute to the 

10 A (angstrom) XRD peal<. It probably represents a mixture of 

fine-grained mica and illite. 

made continuously from start to finish insofar as the length 

of the work day allowed. The second set of XRD data for 

smectite and illite was obtained from oriented glycolated 

mounts of the <2 J.Lm (micrometer) clay size. The values for 

this data are the number of counts from each XRD peak. 

The data base used here is the same as was used by 

Dickinson ( 1988) except that vanadium was substituted for 

LOI (loss on ignition) and the oriented clay mount data was 

included. Because of the close correlation between elements 

determined by ICP and XRF, only Si02 from the XRF data 

was included in the present statistical analysis. 

Correlation coefficient matrices and R-mode factor 

analyses (Harmon, 1960) were calculated from the data base 

using commercially available software (Number Cruncher 

Statistical System, Hintze, 1987) and a personal computer. 

Three-fourths of the lower detection limit was substituted 

for ICP values reported as less-than values. For calculations 

made on log transformations of original values of XRD 

data, 0.00001 was substituted for zero because the log of 

zero is infinity. The factor analyses were performed to 

reduce the number of variables to be interpreted by 

grouping them into related sets. Correlation coefficients 

were also calculated and scatter diagrams were prepared for 

both sets of smectite and illite data. 

Individual statistics were performed on untransformed units for the chemical data (Dickinson, 1988). 

Factor analysis and correlation coefficients were calculated 

for both untransformed units and for log-transformed data. 

Only the results for the log-transformed data are presented 

here because the communality (the proportion that could be 

accounted for by the factor analysis) is higher for uranium. 

2 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
In general only minor differences were found between 

analysis of the original data (Dickinson, 1988) and the 

log-transformed data presented here. 

The results of these studies suggest many interesting 

relationships, and the data can be interpreted to reflect 

sedimentologic and diagenetic processes. Some of the 

results, however, seem to defy interpretation, which may 

reflect lack of randomness in sample collection, too few 

samples, or various degrees of departure from normality of 

data distribution. 

GEOLOGY 

The Chadron and Brule Formations, which constitute 

the Oligocene White River Group, consist mostly of colluvial and alluvial claystone, and mudstone (figs. 2-5). Some 

lacustrine gypsum and limestone are also present. Paleosols 

were developed on some of the flood-plain surfaces 

(Schultz and others, 1955). The ultimate detrital source for 

the White River Group was rocks in the mountains far to the 

west. These rocks included volcanic material from the same 

sources that provided material for air-fall beds found at 

various stratigraphic intervals in the group in the study area. 

The Chadron unconformably overlies the Cretaceous Pierre 

STRATIGRAPHY 

AGE 

FORMA- MEMBER LITHOLOGY-THICKNESS TION 

a.. 

:·.·- .· ~ :~ J_Concretions MIOCENE 0 

::::> 

a: MONR~ CREEK- ~ HARRISON ::.·.c:;:; ~ P w SANDSTONE w 

a: .. 0-400 feet <t .. . ~GERING 

a: .. -' <t ... Brown ·-v - ·-· siltstone XXX XX SILTSTONE 

beds -;-....:___ _ _:_. 

~.x_x x ASH BEDS 

a.. WHITNEY XX XXX ::::> BRULE ·-·- 0 -·-· 0-400 feet a: 

OLIGOCENE ~ E a: EVAPORITES w ORELLA AND > CLASTICS a: 

w UPPER PURPLISH 

t: . - · WHITE LAYER r ·- . --1 1-4 feet s . -.-. 

-. -. MUDSTONE 

CHADRON --·l . ·-· - · 200-600 feet 

-:- __:_-;--~ 

·-· _.....,, .....__ 

EOCENE -- o-oy Interior Paleosol - -- 0• 0-10 feet 

---

-=-----_-) SHALE 

CRETACEOUS PIERRE ---

SHALE -- -1 

--- 1,500 feet ---

- --

VV' 

Figure 2. Stratigraphy of the White River Group near Chadron, northwestern Nebraska. 

z 

0 a: (/) f= w w co a: <t ~ w ~ w (/) a: 

0 ~ u.. 

w <t _J _J 

::::> _J 

a: w 

a: co 0 

w 

z 

w 

u 

0 

~ 

:::::i 

0 

z 

0 

a: 

0 

<t 

r 

u 

(/) 

::::> 

0 w w a: u a: <t w 1- a: w 

a: 

u 

'--- -- --

1 50 

1 00 

50 

Claystone, light-brown, soft, flaky 

Limestone, light-brownish-gray, ostracoda!; 

contains mud crack impressions 

Claystone, light-grayish-brown, crumbly; some 

resistant layers contain abundant clay 

clasts 

1--t---Sample Number 72686-3 

Claystone, light-grayish-brown; contains scattered rounded clay clasts 

Caliche layers 1-2 inches thick 

Claystone, light-grayish-brown, thick-bedded; 

contains scattered rounded clay clasts 

(upper PWL) 

Caliche veins 1-2 inches thick 

Claystone, light-brown, medium- to thickbedded; some layers contain clay clasts 

and are hard 

Claystone, light-grayish-brown, hard (lower 

PWL) 

Claystone; light-grayish-brown, thick-bedded; 

contains clay clasts 

Cal iche and chalcedony layers 

Claystone, light-brown, light-gray-weathering 

Shale, gray to reddish-brown; iron oxide coats 

fractures and calcareous concretions 

Clay, orange-brown 

Figure 3. Generalized stratigraphic section of the White River 

Group at Trunk Butte. 

Shale, although in some areas they are separated by an 

Eocene paleosol, the Interior Paleosol, or by younger 

Cretaceous sedimentary rocks. The Brule, above the Chadron, is in turn overlain by the Miocene Gering Formation of 

the Arikaree Group. 

Chadron Formation 

In northwestern Nebraska the Chadron Formation 

consists mostly of light-gray, green, and nearly white 

claystone and mudstone. It contains prominent beds known 

as "purplish-whiLe beds" (Schultz and Stout, 1955). The top 

of the upper "purplish-white bed" is used as the top of the 

Chadron in this report as was done by Vondra (1958). The 

Chadron contains a basal sandstone facies that was 

Geology 3 
Figure 4. The Chadron and Brule Formations at Trunk Butte. The contact between the Chadron (below) and the Brule (above) 

is top of the prominent bed (A), which is the upper purplish white layer (PWL). Stratigraphic thickness from top of the upper PWL 

to top of the limestone bed (dark layer at top) is 45 feet. 

deposited in channels scoured into the Pierre Shale. This 

facies consists of arkosic, vitric conglomeratic sandstone. It 

is the host rock for the Crow Butte uranium deposit 

(Gjelsteen and Collings, 1988), but it does not extend into 

the present study area and so is not shown in figure 2. 

Purplish-white layers (PWL) are widespread resistant 

white beds of altered calcareous mudstone 1-3 ft thick in 

the Chadron Formation (fig. 4 ). They apparently formed 

from soil development on alluvial or fluvial sediment. They 

have been used as a correlation tool but they are difficult to 

tell apart. Mudstones overlying the purplish-white layers 

typically contain subhorizontal caliche veins, whereas those 

in underlying beds are vertical or nearly vertical. This 

suggests that during caliche formation in the upper mudstones, the purplish-white layers were barriers to vertical 

ground-water circulation. Pellets (rounded clay clasts) are 

common in but not restricted to the purplish-white layers 

(fig. 6). Along Noddings ridge the upper(?) purplish-white 

layer changes from pelletal mudstone on the south through 

an ashy facies to gypsiferous dolomite on the north. The 

gypsiferous dolomite underlies the thickest part of the 

evaporitic facies in the overlying Brule Formation and may 

have been altered diagenetically to gypsum and dolomite by 

brines percolating downward from the overlying playa lake 

(figs. 1, 5). Schultz and Stout (1955), however, reported 

gypsum crusts in PWL' s along the margins of the paleovalleys. The purplish-white samples studied in this report 

contain abundant smectite and a dearth of illite relative to 

the other samples, as will be discussed in the section, 

"Diagenesis." 

Brule Formation 

In northwestern Nebraska the Brule Formation 

contains the Orella and Whitney Members in ascending 

order. An additional informal member called the brown 

siltstone was recognized above the Whitney by Swinehart 

and others (1985). The brown siltstone and the Whitney are 

soft siltstone and fine-grained sandstone that are partly 

eolian in origin. The Orella consists mostly of light-pink to 

brown pelletal mudstone (fig. 7), but in the area of this study 

it contains a playa facies characterized by gypsum, 

dolomite, and limestone of lacustrine origin (figs. 8, 9, 10). 

Swinehart and others (1985) described a regional 

4 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
C'l 

I'!) 

0 

0 

~ 

Vt 

1 MILE___,.. 

3 c 

10 

B 

A 

15 

R 47 W 

T 

34 

N 

NORTH 

c 

-Gypsum, lightyellow-brown; 

uranium mineralization at top 

Claystone, gray to 

yellow-brown, silty; 

many selenite 

veins 

Gypsum, gray to pink, 

hard, clayey 

Claystone, light-gray 

to brown 

Claystone, lightgray to brown 

gypsiferous; 

contains rounded 

clay clasts 

B 

;---;:;-\!sample 7 30866 

_ _ Limestone, light-brown, 

sili/us 

C!,9ystone 

Chalcedony 

Claystone, light-brown, 

crumbly, calcareous 

facies 

"' Cll 

u 

2 

Cll 

c 

c 

ro 

..r:::. 

u 

facies 

Upper? purplish white layer 

FEET 

50 

Figure 5. Generalized stratigraphic section of the White River Group at Noddings ridge. 

/ / 

/ / 

SOUTH 

A 

Sample 81 584-8 

Limestone, gray, siliceous, ostracoda! 

Mudstone and siltstone, pink to buff; ashy in 

places 

Sample 72986-5 

Claystone, light-brown to light-green; silty in 

places; contains rounded clay clasts 

Caliche layers 

Siltstone, grayish-white, ashy; contains clay 

clasts 

Caliche veins 

Claystone, light-grayish-to light-greenish-white; 

silty in places; contains veins and nodules of 

chalcedony 

Sample 72586-1 

o . 0\ Conglomerate, brown, sandy 
Figure 6. Scanning electron micrograph of rounded clay clast in upper purplish white 

layer (PWL) at Noddings ridge (sample 72586-1, locality on fig. 5). 

unconformity within the Brule. Of the samples for this 

study, most were collected from the Orella Member of the 

Brule Formation (Dickinson, 1988, p. 29). 

Facies and Depositional Environments 

Dunham (1955) described two facies, a gypsum 

facies and a clastic facies, in the Orella Member in the 

vicinity of the uranium deposit at Noddings ridge. In this 

report, which covers a somewhat wider area, the Orella 

Member is generally divided into lacustrine and alluvial 

facies. The lacustrine facies contains a gypsum-dolomite 

subfacies, which is mostly gypsum (fig. 9), and a 

widespread, but thin, limestone subfacies (fig. 1 0). The 

alluvial facies can be generally divided into channel and 

flood-plain subfacies (figs. 3, 5). Most of the flood-plain 

rocks have been altered by pedogenesis. The gypsumdolomite subfacies represents deposition from the more 

concentrated brines in the center of the lake basin, and the 

limestone from more dilute water at higher lake levels. The 

ancient lake was more widespread during later, fresher 

water phases. The shallow-water lacustrine limestone 

representing the fresher water phase (fig. 10) extends from 

Noddings ridge to Trunk Butte, a distance of about 15 mi. 

Erosion has removed much of the original playa deposit 

northwest of Isinglass Buttes and Noddings ridge. 

Figure 7. Photomicrograph of pelletal mudstone of the Orella 

Member at Trunk Butte (sample 72683-3). Plane-polarized 

light. 

6 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
Claystone, light-grayish-brown, crumbly 

Gypsum and chalcedony veins 

Claystone, light-brownish-gray; and 

interbeds of light-brownish-gray 

coarse-grained gypsum 

Claystone, light-gray to pink; and 

interbeds of light-brownish-gray 

coarse-grained gypsum 

Gypsum and chalcedony veins 

Claystone, brown, crumbly 

Gypsum 

Sandstone, light-brown, gypsiferous 

Figure 8. Generalized stratigraphic section of 

playa facies of the Orella Member near 

Isinglass Buttes. 

Mineralogy 

The mineral components of the White River Group 

can be classified as detritals, orthochemical precipitates, or 

diagenetic minerals. The detrital minerals, which 

predominate in the clastic rocks, are mainly quartz, feldspar, 

illite, and smectite. The chemical precipitate minerals, 

which predominate in the lacustrine rocks, are gypsum, 

calcite, and dolomite. Much of the calcite, however, is of 

pedogenic (caliche) origin. The predominant diagenetic 

minerals are calcite, gypsum, opal, and chalcedony. 

STATISTICAL ANALYSIS 

A correlation coefficient matrix and a R-mode factor 

analysis based on original units of the data base were 

presented by Dickinson (1988). A correlation coefficient 

matrix (table 2) and a five-factor model (table 3) presented 

herein were calculated from a log-transformed data base. 

The communality (proportion of total variance explained by 

the model for each variable) is higher for uranium here than 

for the original model (Dickinson, 1988). The interpretations of the factor analysis are based on primary factor 

Figure 9. Bedded granular gypsum in evaporite facies of 

the Orella Member at Noddings ridge. 

loadings for each variable, ignoring the fact that secondary 

loadings (where factor loadings are less than the highest for 

a given variable) may also be important in explaining the 

distributions. 

Factor one.-Factor one contains both positive and 

negative groups of loadings. The variables with negative 

factor loadings in order of decreasing factor score are AI, K, 

Fe, Ti, Na, Li, feldspar, smectite, Ba, Cu, Mg, and illite. The 

association of these elements and minerals is believed to be 

controlled by their distribution in the source sediments. 

Volcanic glass was not measured, but any fluvially 

reworked glass would correlate with the detrital group. 

Opal, Ca, and U are the three most strongly loaded positive 

elements in factor one. The association of these elements 

with factor one, but opposite in sign to the preceding group, 

suggests that they are related to the detrital minerals as 

alteration products or as constituents of alteration products. 

Silica and uranium were apparently derived from 

alteration of the volcanic ash. The silica probably formed 

opal and ultimately chalcedony. The explanation for Ca is 

Statistical Analysis 7 
Figure 10. Mudcrack impressions in shallow-water lacustrine 

limestone at Trunk Butte. 

more complex. Its source is the stream and ground water 

and its manner of deposition is varied. 

Factor two.-Factor two contains only gypsum, 

strontium, and dolomite as negative elements and calcite 

and manganese as positive elements. The occurrence of 

gypsum and dolomite represents the evaporitic phase of the 

playa lake. Strontium remained in solution until the gypsum 

was deposited and apparently substituted for Ca in the 

gypsum structure because of their similar charge and size 

2 0 0 

(Ca+ =0.99 A, Sr+2=1.12 A). 

Factor three.-Factor three loads primarily on quartz 

and Si02• The relation between the two is obvious, but parts 

of both the quartz and the Si02 are detrital and parts are 

authigenic. The Si02 also has fairly high factor loadings in 

factors one and two reflecting its occurrence in other 

silicates. 

Factor four.-Factor four exhibits high negative 

loadings for Mg, V, Cu, and Mn. This association is not 

easily explained. The secondary loading for Mg, however, 

associates it with the detrital group, factor one, but it is 

weakly loaded in factor two which contains dolomite. 

Factor five.-In factor five phosphorus loads at one 

pole and illite at the other. Phosphorus is generally related 

to biological activity, which was high during the more 

evaporative stages of the lake. The negative loading of illite 

probably represents the detrital fraction, which is diluted in 

this facies by the lacustrine chemical deposits. Its secondary 

factor loading is with the detrital fraction in factor one. 

In summary, factor one represents detrital materials 

and their alteration products; factors two, three, and four 

represent introduced materials or alteration products from 

detrital materials. Factor two represents playa lake facies. 

Factor four is enigmatic. Factor five may in part reflect 

biological activity. 

DIAGENESIS 

Diagenesis in the lacustrine beds and related mudstones consisted mostly of dissolution and reprecipitation of 

siliceous minerals, carbonates, and sulfates. Some clay 

mineral alteration also occurred. The diagenetic minerals in 

the White River lacustrine and pedogenic sedimentary rocks 

include smectite, calcite, opal, chalcedony, and gypsum. No 

clinoptilolite or kaolinite was found. According to Stanley 

and Benson (1979), diagenetic alteration of Tertiary 

sandstones in the high plains has not been strong, and 

unaltered volcanic shards and feldspar still persist in the 

sediment. Their paragenesis in the sandstone is calcite, first, 

then smectite, kaolinite, and a silica-phase mineral. 

Clinoptilolite is rare in Tertiary high plains sandstones 

(Stanley and Benson, 1979). Paragenesis in the fine-grained 

fluvial and lacustrine rocks of this study is difficult to 

determine using present methods, because the diagenetic 

minerals, except for opal and chalcedony, have also been 

supplied to the sediment both as detrital minerals and as 

precipitates. In addition, the order of formation of some 

diagenetic minerals alternated. For example, figure 11 

shows that calcite was followed by chalcedony in one fossil 

cavity and that calcite followed chalcedony in another 

cavity in the same sample. Another example is that fibrous 

gypsum and a chalcedony alternated in some of the vein 

fillings. These examples are presumably results of the 

fluctuation of the pore-water chemistry. 

The only clay minerals in the samples are smectite 

and illite. Of the two, smectite is more abundant and more 

widespread. In the correlation coefficient matrix the two are 

related (r=+0.39, table 2), probably because of their 

predominantly detrital origin. Small amounts of authigenic 

smectite formed on shards in some of the mudstones (fig. 

12). Smectite formed chiefly as an alteration product of the 

volcanic ash (Zielinski, 1983; also fig. 12). Much of the 

alteration probably took place in the sediment source area, 

and diagenetically produced smectite was transported in 

streams to depositional areas where it became a detrital 

sediment (fig. 13). Some of the alteration could have 

8 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
Figure 11. Photomicrographs of a thin section of limestone under crossed polarizers from the uppermost limestone bed in the 

Orella Member, south end of Noddings ridge (sample 81584-8, fig. 5). A, Fossil cavity with early deposition of chalcedony (outer 

layer) and later calcite in the center. 8, Cavity in ostracode carapace is lined with early calcite, and later chalcedony filled the 

center and replaced parts of the earlier calcite and the limestone matrix. 

occurred diagenetically after the volcanic ash was 

transported, via water or air, to the depositional site (fig. 8). 

The combination of the strong loading of smectite with 

detrital variables (factor 1, table 3) and the detrital texture of 

most of the clay in the mudstone suggests, however, that 

most of the smectite was deposited in a fluvial environment. 

Illite is the other common mineral in the clay mineral 

suite of the samples (Dickinson, 1988); it is less abundant 

than smectite, but like smectite is associated (although 

somewhat less strongly) with the detrital group of elements 

and minerals. If the relative amounts of smectite and illite 

are compared from the oriented clay-mount XRD data (as 

opposed to the whole-rock data), they are negatively 

associated (r=-0.26, significant at 90 percent confidence 

level for normal populations; fig. 14 ). This latter statistic 

may suggest that smectite formed from the illite (Borchardt, 

1977, p. 306, 309; Fanning and Keramidas, 1977, p. 206). 

Authigenic illite was not recognized in the samples studied 

in this report. Little or no interlayered smectite-illite, which 

would have suggested an intermediate stage, was found. 

The illite could be a detrital product of the Mesozoic and 

older crystalline source areas to the west. In PWL's the clay 

is predominantly smectite (fig. 14); illite originally in these 

beds may have been altered to smectite. Such alteration 

would explain the weaker correlation between illite and the 

detrital group of chemicals and minerals (table 3). 

The major carbonate mineral in the study area rocks is 

calcite. Its major occurrences are in the limestone subfacies 

as an orthochemical precipitate and in the alluvial mudstone 

facies as diagenetic caliche and cement deposited during 

pedogenesis. A sparry variety also was deposited in minor 

amounts as cavity filling in the limestone (fig. 11). 

Dolomite is interbedded with gypsum and closely 

associated with it in the statistical analysis (tables 2, 3). 

Gypsum is present only in the lacustrine facies, where 

it occurs in two forms, in fibrous veins and in granular beds 

(figs. 9, 15). The vein-filling gypsum is authigenic and 

alternates with chalcedony in some of the veins. Judging 

from the coarse grain size, the gypsum appears to be 

recrystallized. 

Diagenetic silica phases in the rocks of the study area 

are opal and chalcedony (figs. 16--17). Opal is widespread 

in the limestone subfacies and in some of the calcareous 

mudstones, but is absent from the gypsum-dolomite subfacies. The absence of opal in the gypsum-dolomite subfacies probably results from a higher Mg+ content, which 

has been shown to hasten the alteration from opal to 

microcrystalline quartz (Leeder, 1982; Kastner and others, 

Diagenesis 9 
Table 2. Correlation coefficient matrix of log10-transformed data 

u Al Ca Fe K Mg 

u 1.00 

Al -0.42 1.00 

Ca 0.26 -0.67 1.00 

Fe -0.49 0.96 -0.67 1.00 

K -0.43 0.97 -0.65 0.93 1.00 

Mg -0.29 0.52 -0.24 0.59 0.54 1.00 

Na -0.36 0.95 -0.65 0.88 0.93 0.50 

Mn 0.29 0.01 0.31 -0.07 -0.02 0.25 

p -0.05 0.31 -0.00 0.27 0.27 0.23 

Ti -0.47 0.94 -0.68 0.98 0.91 0.58 

Ba -0.30 0.70 -0.43 0.66 0.67 0.35 

Cu -0.25 0.64 -0.58 0.69 0.62 0.52 

Li -0.51 0.89 -0.62 0.95 0.88 0.66 

Sr -0.00 -0.40 0.33 -0.28 -0.33 -0.04 

Si02 0.04 0.60 -0.66 0.54 0.56 -0.05 

v 0.13 0.40 -0.37 0.34 0.37 0.39 

Dolomite -0.04 -0.36 0.34 -0.28 -0.25 0.22 

Calcite 0.20 0.05 0.23 -0.07 -0.03 -0.29 

Feldspar -0.35 0.72 -0.63 0.74 0.72 0.55 

Quartz -0.00 0.16 -0.37 0.25 0.15 0.08 

Opal 0.49 -0.51 0.35 -0.50 -0.58 -0.45 

Gypsum -0.06 -0.35 0.28 -0.27 -0.25 0.12 

Illite -0.32 0.43 -0.46 0.50 0.39 0.27 

Smectite -0.40 0.69 -0.46 0.60 0.67 0.11 

Li Sr Si02 v Dolomite Calcite 

u 

Al 

Ca 

Fe 

K 

Mg 

Na 

Mn 

p 

Ti 

Ba 

Cu 

Li 1.00 

Sr -0.23 1.00 

Si02 0.46 -0.51 1.00 

v 0.36 -0.46 0.43 1.00 

Dolomite -0.20 0.80 -0.54 -0.35 1.00 

Calcite -0.13 -0.67 0.27 0.24 -0.72 1.00 

Feldspar 0.71 -0.13 0.34 0.28 -0.02 -0.23 

Quartz 0.26 0.11 0.42 0.24 0.11 -0.26 

Opal -0.47 -0.28 0.08 0.05 -0.28 0.44 

Gypsum -0.21 0.84 -0.52 -0.40 0.93 -0.79 

Illite 0.45 -0.14 0.29 0.22 -0.14 -0.16 

Smectite 0.51 -0.07 0.34 0.16 -0.17 -0.05 

10 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
Table 2. Correlation coefficient matrix of log10-transformed data-Continued 

Na Mn p Ti Ba Cu 

u 

Al 

Ca 

Fe 

K 

Mg 

Na 1.00 

Mn 0.18 1.00 

p 0.36 0.42 1.00 

Ti 0.86 -0.08 0.21 1.00 

Ba 0.73 0.29 0.25 0.67 1.00 

Cu 0.61 0.02 0.21 0.69 0.53 1.00 

Li 0.81 -0.05 0.22 0.92 0.66 0.73 

Sr -0.56 -0.59 -0.38 -0.29 -0.52 -0.30 

Si02 0.60 0.01 0.21 0.53 0.50 0.39 

v 0.43 0.32 0.32 0.40 0.45 0.51 

Dolomite -0.46 -0.40 -0.31 -0.26 -0.50 0.20 

Calcite 0.19 0.67 0.39 -0.10 0.29 -0.07 

Feldspar 0.72 -0.20 0.10 0.72 0.39 0.47 

Quartz 0.06 -0.34 -0.06 0.23 0.04 0.29 

Opal -0.45 0.33 -0.01 -0.48 -0.27 -0.21 

Gypsum -0.48 -0.58 -0.33 -0.24 -0.52 -0.24 

Illite 0.38 -0.23 -0.05 0.54 0.28 0.33 

Smectite 0.60 -0.36 -0.01 0.59 0.37 0.28 

Feldspar Quartz Opal Gypsum Illite Smectite 

u 

Al 

Ca 

Fe 

K 

Mg 

Na 

Mn 

p 

Ti 

Ba 

Cu 

Li 

Sr 

Si02 

v 

Dolomite 

Calcite 

Feldspar 1.00 

Quartz 0.34 1.00 

Opal -0.59 0.06 1.00 

Gypsum -0.03 0.14 -0.31 1.00 

Illite 0.47 0.19 -0.28 -0.05 1.00 

Smectite 0.58 0.20 -0.61 -0.08 0.39 1.00 

Diagenesis 11 
Table 3. Varimax factor analysis for five factors: rotated factor loadings 

Variable Factor 1 Factor 2 Factor 3 

u 0.61 0.12 -0.36 

AI -0.93 -0.16 0.24 

Ca 0.62 -0.16 0.49 

Fe -0.91 0.14 -0.17 

K -0.93 0.15 -0.14 

Mg -0.52 -0.23 0.10 

Na -0.87 0.39 -0.09 

Mn 0.19 0.60 0.29 

p -0.23 0.31 0.00 

Ti -0.88 0.13 -0.18 

Ba -0.61 0.49 -0.01 

Cu -0.54 0.14 -0.31 

Li -0.86 0.07 -0.15 

Sr 0.17 -0.88 0.05 

Si02 -0.40 0.51 -0.65 

v -0.20 0.36 -0.43 

Dolomite 0.15 -0.93 0.08 

Calcite 0.14 0.85 0.13 

Feldspar -0.78 -0.12 -0.24 

Quartz -0.11 -0.22 -0.82 

Opal 0.75 0.43 -0.23 

Gypsum 0.12 -0.95 0.04 

Illite -0.44 0.06 -0.12 

Smectite -0.78 0.00 -0.13 

1977). Opal exhibits a poorly ordered cristobalite-tridymite 

(C-T) XRD pattern (Jones and Segnit, 1971) in most of the 

samples. Lepispheres of opal result from diagenetic 

alteration of volcanic ash (fig. 19). In the ash, opal probably 

formed from excess silica released in the formation of 

smectite, and opal is a precursor of chalcedony. The 

distribution of chalcedony is difficult to characterize in this 

study because of the reliance on XRD, with which one does 

not differentiate between the authigenic quartz, chalcedony, 

and the detrital quartz. Some of the silica may have passed 

through an organic phase where it was incorporated in 

diatom frustules in the lacustrine environment, but no 

evidence for the existence of diatoms was found. The 

character of the detrital clays based on X-ray analysis is, 

however, closely similar to that of the authigenic clays 

found in the ash beds, and it is likely that the clays were 

mostly derived from authigenesis of volcanic ash in the 

sediment source area. 

URANIUM 

The Noddings ridge uranium deposit, which as 

presently known is below commercial size, was described in 

detail by Dunham (1955). He found enrichment as high as 

Factor 4 Factor 5 Comm. 

-0.06 0.30 0.61 

-0.13 0.03 0.97 

0.24 0.35 0.78 

-0.22 -0.08 0.94 

-0.14 0.06 0.94 

-0.77 0.08 0.94 

-0.17 0.07 0.95 

-0.50 0.40 0.89 

-0.24 0.64 0.62 

-0.26 -0.14 0.92 

-0.25 -0.03 0.67 

-0.52 -0.16 0.69 

-0.35 -0.12 0.89 

0.19 -0.01 0.84 

0.09 -0.30 0.85 

-0.54 0.12 0.65 

-0.10 0.06 0.91 

0.08 0.31 0.87 

-0.14 -0.05 0.71 

-0.05 -0.07 0.75 

-0.09 -0.05 0.82 

0.40 -0.03 0.93 

-0.15 -0.62 0.61 

0.39 -0.03 0.77 

0.43 percent U30 8 in a lacustrine gypsum facies of the 

Orella Member at that locality (fig. 1). Dunham identified 

three oxidized uranium minerals: carnotite [K20(U02)V 20 5 · 

2H20], sabugulite [HAl(U02)iP04) 4·16H20], and autunite 

[Ca(U02)P20 8 ·8H20]. The uranium deposit was probably 

originally syngenetic [Evaporative precipitates (Class 220), 

Mickle and Mathews (1978)], but subsequent diagenesis 

enriched the deposit locally. 

The statistical analysis of the data base presented 

here, which did not contain uranium-enriched samples, fails 

to show a strong correlation between uranium and any 

element or mineral, but uranium is most closely allied with 

calcium, and opal. Opal and limestone, a major source of 

calcium, occur together in the fresh-water subfacies of the 

lacustrine deposits and may link the uranium with the 

deposition in the lake. In the factor analysis uranium occurs 

with the detritals but is opposite in sign. This association 

suggests that the uranium formed from alteration of the 

detrital materials. It also suggests that the uranium was 

derived from detritally deposited volcanic ash, considering 

that the primary source of the uranium is believed to be 

volcanic material (Zielinski, 1983), which makes up a 

significant proportion of some of the sedimentary beds, not 

only in the vicinity of the occurrence, but also for hundreds 

12 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
Figure 12. Scanning electron micrographs of volcanic ash altered to montmorillonite 

in channel facies of Orella Member at Noddings ridge. Bar scale is for left view, outlined 

portion in left view is magnified three times in right view (sample 72986-5, fig. 5). 

Figure 13. Scanning electron micrograph of detrital clay in upper purplish white 

layer from Noddings ridge (sample 72586-1, fig. 5). 

of miles to the west. Crystalline rocks of the mountains to 

the west probably also contributed part of the uranium 

(Gjelsteen and Collings, 1988). Oxidized uranium dissolved 

in stream and ground water made its way eastward and 

entered the playa lake during deposition of the Brule 

Formation. The uranium was deposited with gypsum from 

the most dense brine when the solubility product was 

exceeded through evaporation or by chemical reduction. 

Dunham (1955) asserted that the uranium minerals were 

associated with carbonaceous material, which indicates 

Uranium 13 
0·08 .----,--I---,--1---..,...I-----,I-------,T---------rl----,---l----, 

(J) 

w 

:I: 

u 

z 

w 

a: 

<( 

::;) 

0.07 ~ 

0.06 1-

0.05 1-

g 0.04 fz 

0 

0 0.03 f- w 

!::: 

...J 

...J 

0.02 f0.01 1-

A 

0 0 

0 0 

0 -

-

0 0 r=+0.39 -

0 -

-

EXPLANATION 

• PWL samples 0 -

o All other samples 

-

O~r&~--~~--~~1-&--~~----~~-~l_.~~l~~.-----~11-~&-----~1------~ 

(J) 

1-

z 

::;) 

0 

u 

~ 

<( 

a: 

<.:) 

0 

1-

u 

<( 

a: 

LL 

LL 

a 

~ 

<( 

a: 

x 

0 

0 

w 

1-

::::i 

...J 

0 0 .05 0.1 0 .1 5 0.2 0.25 0.3 0.35 0.4 

SMECTITE 001 , IN SQUARE INCHES 

160~---------~~-------------~~------------,l-------------l,--------------

1401-

1201-

100 f80 f601-

0 

40 'o 

0 ~ 

0 

B 

0 

0 

0 

0 

0 0 

• 

0 

0 

0 

0 0 

I 

500 

0 

0 

0 

0 

0 

0 0 

0 

0 

I 

• 

1000 

0 

I 

1500 

SMECTITE 001 , X-RAY DIFFRACTOGRAM COUNTS 

· -

-

r=-0.26 -

-

EXPLANATION -

• PWL samples 

o All other samples -

• -

- I 

-2000 2500 

Figure 14. Scatterplots showing relation between illite and smectite X-ray diffraction data from purplish-white layers (PWL) and 

other samples. A, From whole-rock XRD data (based on areas in square inches of basal XRD peaks); 8, From oriented <2 J..Lm 

glycolated claymount data (based on XRD counts). 

14 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
Figure 15. Vein in the Orella Member at Noddings ridge. The 

center is fibrous gypsum, and marginal layers are chalcedony. 

Scintillometer is 2.5 in. wide. 

precipitation by reduction. Little evidence for carbonaceous 

material was noted in these rocks, but in either case, the 

uranium minerals were later altered (and concentrated?) 

during diagenesis. 

Despite Dunham's (1955) reported occurrence of the 

uranium-vanadium mineral carnotite in the lacustrine facies, 

a valid correlation between uranium and vanadium could 

not be established using the data presented in this report 

(table 2). This lack of correlation, however, does not reflect 

an association that would probably have occurred in a data 

set containing only enriched samples. Among the chemical 

elements, vanadium is most closely allied with copper 

(r =+0.51, table 2), and among the minerals it is most closely 

related to feldspar (r =+0.28, table 2). The significance of its 

relation to copper is not understood, but its association with 

feldspar suggests a detrital link. 

Figure 16. Photomicrograph of thin section of fibrous 

gypsum (sample 72183-7, fig. 5) with one prismatic crystal 

replaced by chalcedony. Plane-polarized li-ght. 

SUMMARY 

1. The diagenetic minerals in the White River 

Group are mainly smectite, gypsum, opal, calcite, dolomite, 

quartz, and uranium minerals. 

2. Electron micrographs of the White River mudstone and clay show both authigenic and detrital types, but 

statistical comparison of the clays to detrital minerals and 

chemical elements related to them indicate that the clays are 

predominantly of detrital origin. 

3. Purplish-white layers in the Chadron Formation 

lack illite relative to smectite, suggesting that illite was 

destroyed or altered to smectite, probably during pedogenesis. 

4. Enriched uranium at the Noddings ridge deposit 

is associated with the most evaporitic phases of the lacustrine deposition, but has been oxidized and does not 

correlate with any of the variables related to the lacustrine 

evaporitic stage. 

5. In the White River Group in the Dawes County, 

Nebr., area, uranium is correlated with opal, which occurs 

primarily in the lacustrine limestone subfacies. This 

uranium has not been enriched. 

Summary 15 
Figure 17. Photomicrograph of thin section of calcareous 

mudstone from the Chadron Formation(?) about 2 mi southeast 

of the south end of Noddings ridge, in which interstitial 

prismatic gypsum crystals have been replaced by opal (sample 

81484-1 ). Plane-polarized light. Sample locality is near center 

of sec. 24, T. 34 N., R. 47 W. 

REFERENCES CITED 

Borchardt, G.A., 1977, Smectite and other smectite minerals, 

chapter 9 in Dixon, J.B., and Weed, S.B., eds., Minerals in 

soil environments: Madison, Wis., Soil Science Society of 

America, p. 293-330. 

Burchett, R.R., 1986, Geologic bedrock map of Nebraska: 

Nebraska Geological Survey, scale 1:1,000,000. 

Collings, S.P., and Knode, R.H., 1984, Geology and discovery of 

the Crow Butte uranium deposit, Dawes County, Nebraska: 

American Institute of Mining Engineers, Practical 

Hydromet'83, 7th Annual Symposium on Uranium and 

Precious Metals, p. 5-14. 

Crock, J.G., Lichte, F.E., and Briggs, P.H., 1983, Determination of 

elements in National Bureau of Standards' geological 

reference materials SRM 278 obsidian and SRM 688 basalt 

by inductively coupled argon plasma-atomic emission 

spectrometry: Geostandards Newsletter, v. 7, no. 2, 

p. 335-340. 

Dickinson, K.A., 1988, A preliminary statistical analysis of some 

chemical and mineralogic data from lacustrine beds in the 

Oligocene White River Group in Dawes County, Nebraska: 

U.S. Geological Survey Open-File Report 88-449, 35 p. 

Dunham, R.J., 1955, Uranium minerals in the Oligocene gypsum 

near Chadron, Dawes County, Nebraska: U.S. Atomic 

Energy Commission, Trace Elements Investigations Report 

525, 31 p. 

Fanning, D.S., and Keramidas, V.Z., 1977, Micas, chapter 7 in 

Dixon, J.B., and Weed, S.B., eds., Minerals in soil 

environments: Madison, Wis., Soil Science Society of 

America, p. 195-258. 

Gjelsteen, T.W., and Collings, S.P., 1988, Relationship between 

ground water flow and uranium mineralization in the 

Chadron Formation, northwest Nebraska: Wyoming 

Geological Association Guidebook, Thirty-ninth Field 

Conference, p. 271-284. 

Harmon, H.H., 1960, Modern factor analysis: Chicago, Ill., 

University of Chicago Press, 2nd revised ed., 471 p. 

Hintze, J.L., 1987, Number Cruncher Statistical System, version 

5.01, reference manual: Kaysville, Utah, Jerry L. Hintze, 

286 p. 

Jones, J.B., and Segnit, E.R., 1971, The nature of opal, 

!-Nomenclature and constituent phases: Journal of the 

Geological Society of Australia, v. 18(1), p. 57-68. 

Kastner, M., Keene, J.B., and Gieskes, M., 1977, Diagenesis of 

siliceous oozes, !-Chemical controls on the rate of opal-A 

to opal-CT transformation-An experimental study: 

Geochimica et Cosmochimica Acta, v. 41, p. 1041-1054. 

Leeder, M.R., 1982, Sedimentology, process and product: London, 

Allen and Unwin, 344 p. 

Mickle, D.G., and Mathews, G.W., 1978, Geologic characteristics 

of environments favorable for uranium deposits: Bendix 

Field Engineering Corporation, GJBX-67(78), 250 p. 

Millard, D.J., Jr., 1976, Determinations of uranium and thorium in 

USGS Standard rocks by the delayed-neutron technique: 

U.S. Geological Survey Professional Paper 840, p. 61-65. 

Schultz, C.B., and Stout, T.M., 1955, Classification of Oligocene 

sediments in Nebraska: University of Nebraska State 

Museum Bulletin, v. 4, no. 2, p. 17-52. 

Schultz, C.B., Tanner, L.G., and Harvey, Cyril, 1955, Paleosols of 

the Oligocene of Nebraska: University of Nebraska State 

Museum Bulletin, v. 4, no. 1, 15 p. 

Stanley, K.O., and Benson, L.V., 1979, Early diagenesis of high 

plains Tertiary vitric and arkosic sandstone, Wyoming and 

Nebraska: Society of Economic Paleontologists and 

Mineralogists Special Publication 26, p. 401-423. 

Swinehart, J.B., Souders, V.L., DeGraw, H.M., and Diffendal, R.F., 

Jr., 1985, Cenozoic paleogeography of Western Nebraska, 

in Flores, R.M., and Kaplan, S.S., eds., Cenozoic paleogeography of West-Central United States: Society of 

Economic Paleontologists and Mineralogists, Rocky 

Mountain Section, 1985, p. 209-229. 

Vondra, C. F., 1958, The stratigraphy of the Chadron Formation in 

northwestern Nebraska: Lincoln, Nebr., University of 

Nebraska M.S. thesis, 138 p. 

Zielinski, R.A., 1983, Tuffaceous sediments as source rocks for 

uranium-A case study of the White River Formation, 

Wyoming: Journal of Geochemical Exploration, v. 18, 

p. 285-306. 

16 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
Figure 18. Scanning electron micrographs of siliceous veins in limestone from 

uppermost part of the Orella (sample 730866, fig. 5). A, Texture of opal or chalcedony 

surface. B, Opal or chalcedony in fracture. Bar scale is for left view; outlined portion in 

left view is magnified three times in right view. 

References Cited 17 
Figure 19. Scanning electron micrograph of air-fall volcanic ash (upper Whitney ash) 

from Round Top area, about 10 mi west of study area. Reticulated material is authigenic 

smectite; circular crystalline clusters are opal lepispheres (sample 82885-2). 

18 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
Appendix. Chemical and Mineralogic Data for Samples of the White River Group, Dawes 

County, Nebr. 

Chemicals are given in ppm (parts per million) or percent as indicated at the top of each column. Minerals are given as XRD peak areas in square inches 

except for the first set of smectite and illite data, the oriented-mount data, which is given in XRD counts. Asterisks are used where estimated values are 

substituted for less-than values. 

Lab No. Field No. Formation Locality 

D-260774 F71683-3 Brule S29-R48W-T34N Isinglass Buttes. 

D-260775 F71683-4 Brule S29-R48W-T34N Do. 

D-260776 F71683-5 Brule S29-R48W-T34N Do. 

D-260777 F71683-6 Brule S29-R48W-T34N Do. 

D-260778 F71883-1 Brule S 15-R48W-T34N Do. 

D-260779 F71883-3 Brule S 15-R48W-T34N Do. 

D-260780 F71883-5 Brule S15-R48W-T34N Do. 

D-260781 F71883-7 Brule S 15-R48W-T34N Do. 

D-260782 F71883-9 Brule S15-R48W-T34N Do. 

D-260783 F71883-11 Brule S15-R48W-T34N Do. 

D-260784 F71983-3 Brule S23-R48W-T34N Do. 

D-260785 F72183-7 Chadron S3-R47W-T34N Noddings ridge. 

D-260786 F72183-8 Brule S3-R47W-T34N Do. 

D-260787 F72183-9 Brule S3-R47W-T34N Do. 

D-260788 F72183-10 Brule S3-R47W-T34N Do. 

D-260789 F81584-4 Brule S3-R47W-T34N Do. 

D-260790 F81584-5 Brule S3-R47W-T34N Do. 

D-260791 F81584-6 Brule S3-R47W-T34N Do. 

D-260792 F81584-7 Brule S3-R47W-T34N Do. 

D-260793 F81584-8 Brule S3-R47W-T34N Do. 

D-278830 F72586-1 Brule S3-R47W-T34N Do. 

D-278831 F72586-2 Brule S3-R47W-T34N Do. 

D-278832 F72586-3 Brule S3-R47W-T34N Do. 

D-278833 F72586-4 Brule S3-R47W-T34N Do. 

D-278834 F72586-5 Brule S3-R47W-T34N Do. 

D-278835 F72586-6 Brule S3-R47W-T34N Do. 

D-278836 F72686-1 Chadron S36-R50W-T33N Trunk Butte. 

D-278837 F72686-2 Chadron S36-R50W-T33N Do. 

D-278838 F72686-3 Brule S36-R50W-T33N Do. 

D-278839 F72686-4 Brule S36-R50W-T33N Do. 

D-278840 F72686-5 Brule S36-R50W-T33N Do. 

D-278843 F72886-1 Chadron S36-R50W-T33N Do. 

D-278844 F72886-2 Chadron S36-R50W-T33N Do. 

D-279945 F72886-3 Chadron S36-R50W-T33N Do. 

D-278855 F72886-4 Brule S36-R50W-T33N Do. 

D-278856 F72886-5 Brule S36-R50W-T33N Do. 

D-278857 F72886-6 Brule S36-R50W-T33N Do. 

D-278846 F72886-7 Brule S36-R50W-T33N Do. 

D-278847 F72886-8 Chadron S36-R50W-T33N Do. 

D-278848 F72886-9 Chadron S36-R50W-T33N Do. 

D-278849 F72986-1 Chadron S 15-R47W-T34N Noddings ridge. 

D-278850 F72986-2 Chadron S15-R47W-T34N Do. 

D-278851 F72986-3 Brule S15-R47W-T34N Do. 

D-278852 F72986-12 Brule S10-R47W-T34N Do. 

D-278853 F72986-13 Chadron S 1 O-R47W-T34N Do. 

D-278854 F72986-14 Chadron S10-R47W-T34N Do. 

Appendix 19 
Field No. Lithology 

F71683-3 Limestone, gray, siliceous 

F71683-4 Limestone, gray, pure 

F71683-5 Clay, pink, pelletal 

F71683-6 Sandstone, It. yellow to gray 

F71883-1 Gypsum, lt. brown to gray 

F71883-3 Gypsum, It. yellow to brown 

F71883-5 Clay, pink to lt. gray 

F71883-7 Gypsum, It. brown, crystalline 

F71883-9 Gypsum, gray, crystalline 

F71883-11 Gypsum, gray, crumbly, clayey 

F71883-3 Mudstone, gray, noncalcareous 

F72183-7 Dolomite, gray, hard (PWL) 

F72183-8 Gypsum, gray, hard, clayey 

F72183-9 Mudstone, lt. yellow brown 

F72183-10 Gypsum, lt. brown, thin-bedded 

F81584-4 Siltstone, It. gray, laminated 

F81584-5 Sandstone, lt. brown, fine 

F81584-6 Mudstone, lt. yellow-brown 

F81584-7 Limestone, It. brown 

F81584-8 Limestone, It. brown-gray 

F72586-1 Mudstone, white, pelletal 

F72586-2 Limestone, white, sandy 

F72586-3 Mudstone, white, pelletal 

F72586-4 Limestone, white to It. gray 

F72586-5 Limestone, white, Mn on fract. 

F72586-6 Limestone, white, ashy 

F72686-l Mudstone, buff, pelletal 

F72686-2 Mudstone, buff, pelletal 

F72686-3 Mudstone, buff, thin-bedded 

F72686-4 Limestone, lt. brown, siliceous 

F72686-5 Limestone, lt. brown, laminated 

F72886-l Mudstone, white (PWL) 

F72886-2 Mudstone, white (PWL) 

F72886-3 Mudstone, white (PWL) 

F72886-4 Mudstone, brown, pelletal 

F72886-5 Mudstone, lt. gray (blue ash) 

F72886-6 Mudstone, brown, massive 

F72886-7 Mudstone, lt. gray (PWL) 

F72886-8 Mudstone, lt. gray, calcareous 

F72886-9 Mudstone, lt. gray, calichified 

F72986-1 Mudstone, white, pelletal (PWL) 

F72986-2 Mudstone, white, pelletal (PWL) 

F72986-3 Mudstone, white, crumbly 

F72986-12 Mudstone, gray, pelletal (PWL) 

F72986-13 Chalcedony, replaced limestone 

F72986-14 Mudstone, white (PWL) 

20 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 
Field No. Uranium 

(ppm) 

F71683-3 32 

F71683-4 22 

F71683-5 15 

F71683-6 47 

F71883-1 5.8 

F71883-3 4.1 

F71883-5 19 

F71883-7 6.7 

F71883-9 .94 

F71883-11 4.6 

F71983-3 5.5 

F72183-7 7.5 

F72183-8 8.8 

F72183-9 3.5 

F72183-10 41 

F81584-4 5.1 

F81584-5 4.3 

F81584-6 5.9 

F81584-7 11 

F81584-8 9.6 

F72586-1 2.6 

F72586-2 10 

F72586-3 6.3 

F72586-4 8.3 

F72586-5 2.9 

F72586-6 9.1 

F72686-1 3.9 

F72686-2 7.0 

F72686-3 7.1 

F72686-4 16 

F72686-5 5.9 

F72886-1 4.2 

F72886-2 6.2 

F72886-3 7.3 

F72886-4 2.4 

F72886-5 4.1 

F72886-6 3.2 

F72886-7 5.2 

F72886-8 8.1 

F72886-9 4.6 

F72986-1 3.5 

F72986-2 6.0 

F72986-3 3.7 

F72986-12 7.7 

F72986-13 15 

F72986-14 6.4 

Average 9.27 

Std. Dev. 9.29 

Aluminum Calcium 

(pet) (pet) 

0.33 15 

2.1 26 

2.6 24 

.59 34 

1.4 18 

.65 21 

.45 23 

.90 20 

.60 23 

1.6 19 

7.3 1.4 

3.5 

.70 

4.8 

.31 

6.8 

5.3 

7.0 

1.8 

.30 

3.8 

2.4 

5.5 

.37 

.25 

5.0 

6.6 

5.6 

2.1 

.79 

.58 

6.0 

6.6 

6.7 

6.5 

7.6 

6.9 

6.9 

6.4 

7.7 

7.7 

5.7 

6.2 

6.3 

.41 

5.0 

3.80 

2.73 

13 

23 

11 

13 

3.2 

4.5 

1.5 

19 

24 

22 

19 

13 

27 

40 

14 

5.4 

8.5 

14 

16 

33 

11 

3.7 

3.6 

8.4 

5.6 

1.3 

1.7 

3.3 

1.0 

1.3 

8.5 

7.3 

5.1 

2.4 

9.1 

13.5 

9.85 

Iron 

(pet) 

0.10 

.73 

.74 

.21 

.66 

.33 

.18 

.41 

.26 

.80 

2.6 

1.4 

.29 

1.3 

.12 

2.8 

2.0 

3.3 

.89 

.13 

1.3 

1.2 

1.2 

.15 

.13 

.39 

2.2 

1.3 

.72 

.32 

.22 

1.8 

1.6 

2.0 

2.5 

1.8 

2.9 

1.9 

1.9 

2.8 

2.6 

1.3 

1.9 

1.4 

.12 

.84 

1.21 

.915 

Potassium Magnesium Sodium 

(pet) (pet) (pet) 

0.15 0.13 0.05 

.61 .69 .23 

.46 .89 .16 

.20 .39 .08 

.67 5.1 .16 

.45 1.5 .05 

.25 9.0 .11 

.39 .41 .07 

.32 .21 .03 

.89 .55 .08 

1.9 1.8 .96 

1.4 

.27 

1.2 

.12 

1.9 

1.8 

2.2 

.68 

.10 

1.1 

.94 

2.0 

.15 

.07 

2.7 

2.1 

2.0 

.45 

.27 

.22 

1.7 

2.2 

2.3 

1.8 

1.7 

2.2 

2.0 

2.0 

2.3 

2.2 

2.1 

1.8 

2.7 

.16 

1.5 

1.23 

.853 

5.9 

.19 

1.2 

.09 

1.5 

.67 

1.5 

.67 

.29 

.89 

.82 

1.2 

.35 

.38 

.42 

.95 

.60 

.48 

.26 

.36 

.98 

.81 

.87 

1.3 

1.1 

1.2 

.99 

.99 

1.3 

1.3 

.79 

1.1 

.60 

.09 

.80 

1.17 

1.57 

.60 

.06 

.65 

.02 

.95 

1.2 

.77 

.21 

.05 

.50 

.23 

.77 

.05 

.05 

1.3 

1.4 

1.5 

.36 

.16 

.17 

1.0 

1.5 

1.6 

1.0 

1.7 

1.1 

1.4 

1.3 

1.2 

1.1 

1.2 

1.1 

1.7 

.06 

.85 

.669 

.565 

Appendix 21 
Field No. 

F71683-3 

F71683-4 

F71683-5 

F71683-6 

F71883-1 

F71883-3 

F71883-5 

F71883-7 

F71883-9 

F71883-11 

F71983-3 

F72183-7 

F72183-8 

F72183-9 

F72183-10 

F81584-4 

F81584-5 

F81584-6 

F81584-7 

F81584-8 

F72586-1 

F72586-2 

F72586-3 

F72586-4 

F72586-5 

F72586-6 

F72686-1 

F72686-2 

F72686-3 

F72686-4 

F72686-5 

F72886-1 

F72886-2 

F72886-3 

F72886-4 

F72886-5 

F72886-6 

Manganese 

(ppm) 

2,100 

2,900 

2,000 

2,800 

1,200 

330 

3,000 

63 

39 

120 

150 

3,300 

45 

93 

71 

420 

630 

340 

1,300 

940 

3,200 

1,300 

1,300 

1,400 

2,300 

1,900 

690 

1,100 

1,300 

1,200 

2,300 

1,100 

590 

630 

990 

920 

270 

F72886-7 360 

F72886-8 450 

F72886-9 310 

F72986-1 340 

F72986-2 1 ,500 

F72986-3 1 ,200 

F72986-12 1,100 

F72986-13 380 

F72986-14 1,600 

Average 

Std. Dev. 

1,120 

911 

Phosph. 

(pet) 

0.06 

.34 

.04 

.03 

.04 

.03 

.08 

.01 

.05 

.03 

.08 

.05 

.01 

.05 

.01 

.07 

.08 

.04 

.05 

.04 

.11 

.05 

.06 

.05 

.03 

.02 

.03 

.26 

.37 

.03 

.03 

.08 

.02 

.07 

.06 

.08 

.08 

.02 

.37 

.01 

.02 

.07 

.07 

.19 

.03 

.28 

.080 

.092 

Titanium 

(pet) 

0.01 

.08 

.08 

.03 

.07 

.03 

.02 

.04 

.03 

.08 

.31 

.15 

.03 

.18 

.01 

.29 

.27 

.36 

.10 

.01 

.13 

.11 

.12 

.02 

.01 

.06 

.27 

.09 

.06 

.03 

.02 

.15 

.15 

.13 

.20 

.34 

.29 

.16 

.11 

.29 

.31 

.10 

.15 

.13 

.02 

.08 

.124 

.102 

Barium 

(ppm) 

55 

410 

110 

95 

140 

67 

82 

65 

59 

76 

630 

350 

54 

210 

41 

610 

790 

560 

220 

130 

3,300 

360 

5,100 

170 

130 

750 

790 

370 

140 

1,900 

79 

460 

380 

340 

430 

830 

750 

340 

350 

660 

590 

650 

330 

360 

110 

190 

535 

868 

Copper 

(ppm) 

2.0 

8.0 

9.0 

4.0 

13 

4.0 

15 

5.0 

2.0 

7.0 

19 

7.0 

4.0 

7.0 

.75* 

21 

11.0 

22.0 

3.0 

1.0 

15.0 

12 

12 

13 

.75* 

6.0 

15 

6.0 

27 

7.0 

2.0 

16 

35 

8.0 

20 

7.0 

30 

15 

56 

23 

22 

9.0 

14 

8.0 

10 

1.0 

12.1 

10.4 

22 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 

Lithium 

(ppm) 

2.0 

12 

12 

4.0 

19 

7.0 

9.0 

14 

7.0 

21 

47 

32 

5.0 

22 

3.0 

49 

22 

45 

23 

4.0 

28 

31 

43 

6.0 

4.0 

10 

29 

17 

18 

9.0 

6.0 

39 

27 

33 

53 

15 

50 

31 

33 

54 

62 

22 

35 

21 

4.0 

15 

22.9 

16.1 

Strontium 

(ppm) 

160 

550 

420 

410 

1,500 

2,200 

1,200 

4,100 

1,900 

2,600 

310 

430 

1,900 

620 

7,100 

410 

350 

340 

390 

340 

420 

400 

340 

290 

340 

150 

390 

280 

280 

320 

400 

380 

260 

280 

340 

350 

570 

280 

300 

340 

340 

280 

320 

260 

210 

320 

775 

1,210 
Field No. Si02 

(pet) 

F71683-3 64 

F71683-4 28 

F71683-5 31 

F71683-6 14 

F71883-1 21 

F71883-3 13 

F71883-5 3.7 

F71883-7 19 

F71883-9 7.5 

F71883-ll 20 

F71983-3 64 

F72183-7 30 

F72183-8 8.6 

F72183-9 40 

F72183-10 48 

F81584-4 62 

F81584-5 68 

F81584-6 63 

F81584-7 47 

F81584-8 42 

F72586--l 29 

F72586--2 43 

F72586--3 44 

F72586-4 33 

F72586--5 2.9 

F72586-6 47 

F72686--1 59 

F72686--2 56 

F72686--3 56 

F72686-4 59 

F72686--5 19 

F72886--1 48 

F72886--2 63 

F72886--3 62 

F72886-4 51 

F72886--5 54 

F72886-6 65 

F72886--7 66 

F72886-8 62 

F72886--9 63 

F72986--l 64 

F72986--2 56 

F72986--3 55 

F72986--12 61 

F72986--13 90 

F72986--14 57 

Average 44.7 

Std. Dev. 20.6 

0.73 

3.9 

4.8 

1.1 

2.5 

1.1 

.78 

17 

.98 

2.7 

14 

6.2 

1.2 

8.8 

13 

10 

14 

.64 

3.3 

.63 

6.4 

4.1 

9.3 

.74 

.47 

8.6 

12 

9.4 

3.7 

1.6 

1.0 

10 

12 

12 

11 

14 

12 

12 

12 

14 

14 

9.8 

11 

11 

1.5 

8.6 

6.84 

4.92 

0.08 

.95 

.95 

.21 

.85 

.39 

.19 

.50 

.28 

.96 

3.6 

1.9 

.31 

1.7 

.13 

3.8 

2.7 

4.7 

1.1 

.12 

1.7 

1.6 

1.7 

.13 

.10 

.49 

3.2 

1.8 

.93 

.36 

.22 

2.6 

2.3 

2.7 

3.6 

2.6 

4.1 

2.7 

2.9 

3.9 

3.7 

1.7 

2.6 

2.0 

.09 

1.1 

1.66 

1.32 

MgO 

(pet) 

0.26 

1.2 

1.4 

.69 

8.1 

2.3 

16 

.65 

.40 

.82 

3.0 

10 

.35 

1.9 

.18 

2.5 

1.1 

2.6 

1.1 

.51 

1.4 

1.3 

1.9 

.59 

.67 

.70 

1.6 

1.0 

.77 

.43 

.61 

1.6 

1.3 

1.4 

2.0 

1.8 

1.9 

1.7 

1.6 

2.1 

2.2 

1.3 

1.8 

.98 

.02 

1.3 

1.94 

2.76 

CaO 

(pet) 

19 

35 

33 

47 

24 

29 

31 

26 

31 

25 

1.8 

18 

30 

14 

17 

4.3 

5.9 

2.0 

25 

31 

30 

25 

17 

36 

54 

19 

7.3 

12 

18 

20 

44 

15 

5.0 

4.9 

11 

7.6 

1.7 

2.2 

4.5 

1.3 

1.6 

11 

9.7 

6.8 

3.1 

12 

18.0 

13.2 

0.11 

.35 

.25 

.11 

.22 

.11 

.20 

.11 

.11 

.15 

1.4 

.78 

.11 

.89 

.11 

1.3 

1.7 

1.1 

.29 

.11 

.62 

.35 

.91 

.11 

.11 

1.5 

1.6 

1.8 

.40 

.11 

.21 

1.1 

1.9 

1.9 

1.2 

2.2 

1.4 

1.8 

1.4 

1.5 

1.4 

1.4 

1.4 

2.1 

.11 

.95 

.844 

.680 

0.15 

.68 

.51 

.21 

.72 

.51 

.26 

.44 

.33 

.94 

2.4 

1.5 

.28 

1.5 

.13 

2.4 

2.2 

2.8 

.74 

.10 

1.2 

1.0 

2.2 

.15 

.08 

3.1 

2.5 

2.4 

.48 

.28 

.20 

2.0 

2.7 

2.8 

2.1 

2.0 

2.6 

2.4 

2.6 

2.8 

2.6 

2.4 

2.0 

3.3 

.16 

1.7 

1.44 

1.04 

Appendix 23 
Field No. 

F71683-3 

F71683-4 

F71683-5 

F71683-6 

F71883-1 

F71883-3 

F71883-5 

F71883-7 

F71883-9 

F71883-11 

F71983-3 

F71183-7 

F72183-8 

F72183-9 

F72183-10 

F81584-4 

F81584-5 

F81584-6 

F81584-7 

F81584-8 

F72586-1 

F72586-2 

F72586-3 

F72586-4 

. F72586-5 

F72586-6 

F72686-1 

F72686-2 

F72686-3 

F72686-4 

F72686-5 

F72886-1 

F72886-2 

F72886-3 

F72886-4 

F72886-5 

F72886-6 

F72886-7 

F72886-8 

F72886-9 

F72986-1 

F72986-2 

F72986-3 

F72986-12 

F72986-13 

F72986-14 

Average 

Std. Dev. 

(pd) 

0.01 

.12 

.11 

.01 

.09 

.02 

.01 

.04 

.01 

.10 

.56 

.24 

.02 

.30 

.01 

.50 

.49 

.63 

.13 

.01 

.21 

.18 

.22 

.01 

.01 

.09 

.47 

.16 

.09 

.03 

.01 

.30 

.26 

.23 

.41 

.63 

.56 

.27 

.26 

.52 

.56 

.19 

.30 

.22 

.01 

.12 

.213 

.194 

(pet) 

0.13 

.74 

.11 

.07 

.10 

.07 

.17 

.04 

.11 

.07 

.19 

.12 

.04 

.11 

.04 

.17 

.21 

.10 

.11 

.09 

.23 

.12 

.13 

.11 

.07 

.04 

.06 

.55 

.74 

.06 

.06 

.18 

.04 

.14 

.14 

.21 

.19 

.04 

.87 

.04 

.04 

.15 

.16 

.39 

.05 

.58 

.177 

.197 

MnO 

(ppm) 

0.26 

.37 

.25 

.34 

.14 

.02 

.36 

.01 

.01 

.01 

.01 

.44 

.04 

.01 

.01 

.05 

.08 

.04 

.16 

.10 

.40 

.16 

.16 

.16 

.27 

.25 

.08 

.14 

.16 

.13 

.27 

.14 

.07 

.08 

.12 

.12 

.03 

.04 

.05 

.03 

.04 

.19 

.16 

.14 

.04 

.20 

.138 

.114 

v 

(ppm) 

16 

29 

29 

37 

27 

21 

40 

18 

20 

18 

8.7 

27 

20 

14 

12 

9.9 

6.7 

9.4 

22 

25 

28 

24 

21 

29 

42 

19 

13 

15 

19 

18 

35 

18 

11 

11 

17 

15 

9.5 

11 

11 

11 

10 

15 

15 

11 

4.0 

16 

18.6 

8.78 

24 Uranium and Diagenesis, Oligocene White River Group, Dawes County, Nebr. 

Smectite 

001 peak 

(counts) 

92 

320 

0.0 

0.0 

380 

0.0 

68 

440 

190 

140 

630 

77 

720 

800 

350 

480 

760 

430 

57 

57 

44 

71 

350 

21 

100 

560 

200 

950 

720 

50 

110 

410 

1,000 

1,200 

2,400 

1,100 

92 

2,000 

300 

960 

900 

1,600 

1,400 

300 

0.0 

1,100 

518 

543 

Illite 

001 peak 

(counts) 

27 

25 

0.0 

0.0 

140 

0.0 

29 

86 

55 

79 

55 

29 

140 

58 

38 

39 

44 

40 

17 

0.0 

0.0 

32 

27 

38 

22 

26 

37 

35 

86 

43 

47 

0.0 

12 

0.0 

18 

0.0 

110 

0.0 

10 

40 

47 

0.0 

22 

35 

0.0 

0.0 

34.5 

34.2 
Field Dolo. 

No. (in.2 ) 

F71683-3 0.0 

F71683-4 0.0 

F71683-5 0.0 

F71683-6 0.0 

F71883-1 1.1 

F71883-3 .51 

F71883-5 1.4 

F71883-7 .39 

F71883-9 .35 

F71883-11 .32 

F71983-3 0.0 

F72183-7 1.2 

F72183-8 .94 

F72183-9 .20 

F72183-10 .26 

F81584-4 0.0 

F81584-5 0.0 

F81584-6 0.0 

F81584-7 0.0 

F81584-8 0.0 

F72586-1 0.0 

F72586-2 0.0 

F72586-3 0.0 

F72586-4 0.0 

F72586-5 0.0 

F72586-6 0.0 

F72686-1 0.0 

F72686-2 0.0 

F72686-3 0.0 

F72686-4 0.0 

F72686-5 0.0 

F72886-1 0.0 

F72886-2 0.0 

F72886-3 0.0 

F72886-4 0.0 

F72886-5 0.0 

F72886-6 0.0 

F72886-7 0.0 

F72886-8 0.0 

F72886-9 0.0 

F72986-1 0.0 

F72986-2 0.0 

F72986-3 0.0 

F72986-12 0.0 

F72986-13 0.0 

F72986-14 0.0 

Average 

Std. Dev. 

.145 

.340 

1.1 

1.1 

1.1 

1.5 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

.1 

.3 

0.0 

1.0 

1.1 

1.1 

.96 

.79 

1.4 

1.4 

1.00 

.30 

.60 

.74 

.96 

1.2 

.61 

.23 

.17 

.54 

.42 

0.0 

.05 

.08 

0.0 

0.0 

.64 

.29 

.51 

.16 

.55 

.478 

.479 

*U.S. GOVERNMENT PRINTING OFFICE: 1991-573-049/26042 

0.0 

0.0 

0.0 

0.0 

.03 

0.0 

.03 

.06 

0.0 

0.0 

.23 

.08 

.06 

.46 

0.0 

.27 

1.00 

.20 

.07 

0.0 

0.0 

0.0 

.07 

0.0 

0.0 

0.0 

.18 

.40 

0.0 

0.0 

0.0 

.13 

.16 

.17 

.33 

.06 

.20 

.12 

.08 

.26 

.21 

.07 

.14 

.15 

0.0 

.03 

.114 

.174 

Quar. 

(in.2) 

1.1 

0.0 

.50 

.06 

.34 

.21 

.07 

.30 

.08 

.22 

.75 

.26 

.10 

.58 

1.5 

.58 

.23 

.48 

.32 

.73 

.22 

.22 

.11 

.53 

0.0 

0.0 

.23 

.18 

.10 

.99 

0.0 

.24 

.26 

.15 

.29 

.05 

.53 

.17 

.21 

.45 

.50 

.17 

.22 

.30 

1.8 

.08 

.355 

.365 

0.39 

0.0 

.31 

.15 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

.39 

.33 

0.0 

.26 

0.00 

.23 

0.0 

0.0 

0.0 

0.0 

1.3 

.46 

.21 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

.65 

0.0 

.101 

.232 

0.0 

0.0 

0.0 

0.0 

.61 

1.2 

.26 

.89 

1.2 

1.2 

.02 

.19 

1.1 

.75 

1.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

.183 

.386 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

.05 

0.0 

.07 

.03 

.05 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

.03 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

.02 

0.0 

0.0 

0.0 

0.0 

.04 

0.0 

0.0 

.02 

0.0 

0.0 

0.0 

.007 

.016 

Smectite 

(in.2) 

0.0 

0.0 

.19 

0.0 

0.0 

0.0 

0.0 

.02 

.03 

.01 

.03 

0.0 

.30 

.21 

.01 

.38 

.14 

.25 

0.0 

0.0 

.10 

0.0 

.23 

0.0 

0.0 

.09 

.07 

.11 

0.0 

0.0 

0.0 

.25 

.26 

.14 

.19 

.31 

0.0 

.24 

.26 

.17 

.25 

.23 

.11 

.24 

0.0 

.22 

.110 

.115 

Appendix 25 



SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS 

Periodicals 

Earthquakes & Volcanoes (issued bimonthly). 

Preliminary Determination of Epicenters (issued monthly). 

Technical Books and Repons 

Professional Papers are mainly comprehensive scientific reports of 

wide and lasting interest and importance to professional scientists and engineers. Included are reports on the results of resource studies and of 

topographic, hydrologic, and geologic investigations. They also include 

collections of related papers addressing different aspects of a single scientific topic. 

Bulletins contain significant data and interpretations that are of lasting scientific interest but are generally more limited in scope or 

geographic coverage than Professional Papers. They include the results 

of resource studies and of geologic and topographic investigations; as well 

as collections of short papers related to a specific topic. 

Water-Supply Papers are comprehensive reports that present significant interpretive results of hydrologic investigations of wide interest 

to professional geologists, hydrologists, and engineers. The series covers 

investigations in all phases of hydrology, including hydrogeology, 

availability of water, quality of water, and use of water. 

Circulars present administrative information or important scientific 

information of wide popular interest in a format designed for distribution 

at no cost to the public. Information is usually of short-term interest. 

Water-Resources Investigations Reports are papers of an interpretive nature made available to the public outside the formal USGS publications series. Copies are reproduced on request unlike formal USGS 

publications, and they are also available for public inspection at 

depositories indicated in USGS catalogs. 

Open-File Reports include unpublished manuscript reports, maps, 

and other material that are made available for public consultation at 

depositories. They are a nonpermanent form of publication that may be 

cited in other publications as sources of information. 

Maps 

Geologic Quadrangle Maps are multicolor geologic maps on 

topographic bases in 7 1/2- or 15-minute quadrangle formats (scales mainly 1:24,000 or 1 :62,500) showing bedrock. surficial, or engineering geology. Maps generally include brief texts; some maps include structure 

and columnar sections only. 

Geophysical Investigations Maps are on topographic or planimetric 

bases at various scales; they show results of surveys using geophysical 

techniques, such as gravity, magnetic, seismic, or radioactivity, which 

reflect subsurface structures that are of economic or geologic significance. 

Many maps include correlations with the geology. 

Miscellaneous Investigations Series Maps are on planimetric or 

topographic bases of regular and irregular areas at various scales; they 

present a wide variety of format and subject matter. The series also includes 7 1/2-minute quadrangle photo geologic maps on planimetric bases 

which show geology as interpreted from aerial photographs. Series also 

includes maps of Mars and the Moon. 

Coal Investigations Maps are geologic maps on topographic or 

planimetric bases at various scales showing bedrock or surficial geology, stratigraphy, and structural relations in certain coal-resource areas. 

Oil and Gas Investigations Charts show stratigraphic information 

for certain oil and gas fields and other areas having petroleum potential. 

Miscellaneous Field Studies Maps are multicolor or black-andwhite maps on topographic or planimetric bases on quadrangle or irregular areas at various scales. Pre-1971 maps show bedrock geology 

in relation to specific mining or mineral-deposit problems; post-1971 

maps are primarily black-and-white maps on various subjects such as 

environmental studies or wilderness mineral investigations. 

Hydrologic Investigations Atlases are multicolored or black-andwhite maps on topographic or planimetric bases presenting a wide range 

of geohydrologic data of both regular and irregular areas; principal scale 

is 1:24,000 and regional studies are at 1:250,000 scale or smaller. 

Catalogs 

Permanent catalogs, as well as some others, giving comprehensive listings of U.S. Geological Survey publications are available under 

the conditions indicated below from the U.S. Geological Survey, Books 

and Open-File Reports Section, Federal Center, Box 25425, Denver, 

CO 80225. (See latest Price and Availability List) 

"Publications of the Geological Survey, 1879-1961" may be purchased by mail and over the counter in paperback book form and as a 

set of microfiche. 

"Publications of the Geological Survey, 1962- 1970" may be purchased by mail and over the counter in paperback book form and as a 

set of microfiche. 

"Publications of the U.S. Geological Survey, 1971-1981" may be 

purchased by mail and over the counter in paperback book form (two 

volumes, publications listing and index) and as a set of microfiche. 

Supplements for 1982,1983, 1984, 1985,1986, and for subsequent 

years since the last permanent catalog may be purchased by mail and 

over the counter in paperback book form. 

State catalogs, "List of U.S. Geological Survey Geologic and 

Water-Supply Reports and Maps For (State)," may be purchased by mail 

and over the counter in paperback booklet form only 

"Price and AvailabiUty List of U.S. Geological Survey Publications," issued annually, is available free of charge in paperback booklet form only. 

Selected copies of a monthly catalog "New Publications of the U.S. 

Geological Survey" available free of charge by mail or may be obtained 

over the counter in paperback booklet form only. Those wishing a free 

subscription to the monthly catalog "New Publications of the U.S. 

Geological Survey" should write to the U.S. Geological Survey, 582 

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Note.--Prices of Government publications listed in older catalogs, 

announcements, and publications may be incorrect. Therefore, the 

prices charged may differ from the prices in catalogs, announcements, 

and publications.