Element Distribution 

in Some Trough and 

Platform Types of 

Black Shale and 

Associated Rocks

By JAMES D. VINE, ELIZABETH B. TOURTELOT, and JOHN R. KEITH

CONTRIBUTIO N S T 0 Q E O C H E MI S T R Y

GEOLOGICAL SURVEY BULLETIN 1214-H

The content and association of 

minor elements in different 

black shale environments

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1969
UNITED STATES DEPARTMENT OF THE INTERIOR 

WALTER J. HICKEL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

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

Washington, D.C. 20402 Price 30 cents (paper cover)
CONTENTS

Page

Abstract ----------------.-------------_----------- .---.-__ Hi

Introduction.-_________-__----_._.___.:_-_-_--- __.______ ._-___-_-._ 1

Acknowledgments.__._ _.____..___.._____________... ... _........ 2

Sample 1 .sets.'. _____..____.-______-_._--- t -_-_-___---__-.-.--,'--_......- 4

Belden Shale from Colorado...__._._-___._._._.___..._..._._._. 4

Houy Formation from Texas_-__--___-_-_____-_______._-_._.__ 5

Cherokee Group from Kansas and Oklahoma._.._--__---_.-....-- 6

Upper Paleozoic black shale from Arkansas and Oklahoma.._'.:._... 7

Analytical methods.___-__-._____.________,.-_-_-_--__-_-_---_---.-_ 9

Statistical methods.__.____.__-_-__-______-____..____.____-_-..____ 9

Distribution of elements_.-._..-_..._._._..._..__._...___-_-....__ 12

Belden Shale from Colorado.._______ ____-__________-_-___-____ 15

Houy Formation from Texas--..-----.--.-.---:--_____...... 18

Cfeerokee^ Group -fromr Kansaa'and^Oklfifhoma i. ._-.._...,..._.._-. 24

Upper Paleozoic black shale from Arkansas and Oklahoma.__.... 29

Summary and conclusions...---_.-.-...-..--._-..._..._.._._....__.. 33

References cited..._..._..^.._.....___._._....._....... _._._._..._. 36

ILLUSTRATIONS

FIOURB 1. Map showing sample localities of black shale sample sets

9-12.........._ ___-_..---_.........___ H3

2-5. Rotated two-dimensional vector diagrams showing principal 

components of the correlation matrix for:

2. Set 9, Belden Shale from Colorado.____...._ 16

3. Set 10, Houy Formation from Texas.........-..-. 22

4. Set 11, Gherokee-Grojupvfrom*Kansas.?^and;^'Oklahoma...__._._...--__.!__.-,-__-. ~...'.".- 25

5. Set 12, upper Paleozoic black shale from Arkansas

and Oklahoma.. .. ... 32

zxz
IV CONTENTS

TABLES

Page 

TABLE 1. Substitutions made in the data sets.____________________ Hll

2. Element concentration in four sets of Paleozoic black shale 

PS> samples______-_____-___-______________________.___ 12

, I 3. Coefficients of correlation for element pairs in set 9, 43

samples of Belden Shale from Colorado______________ 17

4. Element associations in set 9, 43 samples of Belden Shale

from Colorado_____________________________________ 18

5. Coefficients of correlation for element pairs in set 10, 51

core samples of the Houy Formation from Texas.______ 20

6. Element associations in set 10, 51 core, samples of the Houy

Formation from Texas__--_-_-,.-_--_--_----_;------.._ 23

7. Coefficients of correlation for element pairs in set 11, 47 

core samples of the Cherokee Group from Kansas and 

Oklahoma. ________________"_______-__^_^____. 26

8. Element associations in set 11, 47 core samples of the

Cherokee Group from Kansas and Oklahoma._________ 28

9i Coefficients of correlation for element pairs in set 12, 30 

samples of upper Paleozoic black shaJe^fronv Arkansas 

and Oklahoma__-___^_v-- T -----------^-->.,--i --.^----r 30

.; 10. Element associations in set 12, 30 samples of upper Paleozoic

black shaie from Arkansas and Oklahoma..-.-..______ 1. 33
CONTRIBUTIONS TO GEOCHEMISTRY

ELEMENT DISTRIBUTION IN SOME TROUGH AND 

PLATFORM TYPES OF BLACK SHALE AND ASSOCIATED

ROCKS

By JAMES D. VINE, ELIZABETH B. TOUKTELOT, and JOHN E. KEITH

ABSTRACT

The distributions of some chemical elements in four sample sets of black shale 

and associated rocks were examined statistically. Pennsylvanian black shales 

deposited in a rapidly subsiding trough in central Colorado show few unusually 

high concentrations of minor elements, except lead, that can be attributed to 

adsorption by organic matter. High concentrations of boron, beryllium, gallium, 

lead, and possibly lithium may be related to Precambrian source rocks that are 

rich in the same elements. Minor elements in upper Paleozoic black shales of the 

Ouachita geosyncline show little or no association with organic matter. Local 

high concentrations of gallium and zirconium are associated with the detrital 

mineral fraction. High concentrations of barium show no association with major 

rock constituents, and barium may have been authigenically redistributed. Samples of shale from the Cherokee Group in the Western Interior coal province 

contain large amounts of silver, chromium, lead, vanadium, and zinc associated 

with organic matter and carbonate minerals. These elements may have been concentrated syngenetically by adsorption from sea water on decaying organic matter 

in a shallow-water platform environment. Samples of black shale and associated 

rocks from the Houy Formation of Devonian and Mississippian age in central 

Texas show unusually high concentrations of many minor elements, including 

cobalt, copper, molybdenum, nickel, lead, thallium, vanadium, and zinc. Of these, 

all but vanadium occur in close association with organic matter and pyrite. A 

very slow rate of deposition may have contributed to the concentration of these 

elements from sea water. However, many of these elements are toxic and could 

not coexist in abundance with living organisms. Some later addition of elements may have occurred.

INTRODUCTION

The present report is the third in a series of reports describing the 

geochemical distribution of elements in black shale and associated 

rocks. The first report (Vine, 1966) describes the element distributions 

in some shelf and eugeosynclinal black shale samples grouped into 

into four sets numbered 1-4. The second report (Vine, 1969) describes

HI
H2 CONTRIBUTIONS TO GEOCHEMISTRY

the geochemistry of four more sample sets, numbered 5-8, representing 

black shales deposited in a hypersaline marine basin, in a miogeosyncline, and in two shallow shelf environments. The present report describes the distribution of major and minor elements in sample sets 

9-12 (fig. 1) which represent black shale and associated rocks deposited 

in intracratonic trough and platform environments.

The term "black shale" as used here, as in previous reports (Vine, 

1966, 1969), indicates dark-colored fine-grained marine sedimentary 

rocks composed of a mixture of detrital minerals, chemically or biologically precipitated minerals, and organic matter. End members include 

claystone, siltstone, limestone, dolomite, anhydrite, chert, phosphorite, 

and coal. Definiton of precise boundaries between black shale and these 

end members is impractical because of the difficulty and expense of determining the exact mineralogic composition of fine-grained rocks, 

even with modern laboratory techniques. Therefore, samples approaching the composition of end members have been included in the study. 

This has increased the range in content of many constituents, thereby 

providing the bivariate statistics that are useful in interpreting the 

distribution of minor elements among different fractions.

ACKNOWLEDGMENTS

Samples were collected from many areas unfamiliar to the authors, 

and the information and guidance given by colleagues familiar with 

the stratigraphy of specific areas are gratefully acknowledged. C. T. 

Wrucke, U.S. Geological Survey, guided the senior author to outcrops 

of the Belden Shale in central Colorado. N. F. Williams, State Geologist of Arkansas, and his staff members, P. J. Sterling and C. G. 

Stone, accompanied the senior author in the field and directed him to 

outcrops of Paleozoic black shales in the Ouachita Mountains. V. E. 

Swanson, U.S. Geological Survey, provided the core of the Houy Formation that was sampled. D. R. Baker, formerly with the Marathon 

Oil Co. Research Center, Littleton, Colo., in cooperation with the 

company management, provided samples from cores of Pennsylvanian 

black shale from southeastern Kansas and northeastern Oklahoma.

The spectrographic analyses upon which this report is based were 

made by A. L. Sutton, Jr., and J. C. Hamilton of the U.S. Geological 

Survey. The other analyses were made by G. T. Burrow, I. C. Frost, 

W. D. Gross, Claude Huffman, Jr., H. H. Lipp, J. D. Mensik, and 

Wayne Mountjoy, all of the U.S. Geological Survey.

M. S. Niles, P. A. Zimmerman, and Josephine Boerngen transcribed 

the analytical data to punch cards. Computer programming and 

assistance were provided by R. N. Eicher, F. B. Sower, and G. I. 

Seiner.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H3

0) a 

a

5

0) 1
H4 CONTRIBUTIONS TO GEOCHEMISTRY

SAMPLE SETS 

BELDEN SHALE FROM COLORADO

The Belden Shale samples from Colorado, set 9, consist of 43 samples collected from outcrops of the Belden Shale of Pennsylvanian 

age and from the lower gradational part of the Minturn Formation, 

also of Pennsylvanian age, in Park, Chaffee, and Fremont Counties, 

Colo. About half the samples were collected from exposures in the 

canyon of the Arkansas River, 5-7 miles southeast of Salida, Colo. 

(Chronic, 1960, map, p. 113). The remainder were collected from 

various exposures north of the river to a point in the Mosquito Range 

west of Fairplay. Among the areas sampled were Trout Creek Pass, 

Chubb Park, Kaufman Ridge, Salt Creek, Weston Pass, and Mount 

Sherman. The samples are mostly channel samples representing 1-5 

feet of stratigraphic thickness, but a few are grab samples representing only a few inches of strata. Generally, each sample represents a 

different bed, but equivalent beds in different sections are probably 

included; detailed correlation between areas was not attempted. The 

rocks sampled are chiefly medium-dark-gray to black arkosic siltstones containing varying amounts of calcite and clay minerals in 

the matrix. Petrographic descriptions of Tennsylvanian clastic rocks 

in this area by Gould (1935) indicate that they are first-cycle detrital 

sediments shed from the ancestral Rocky Mountains into a narrow 

marine trough in Pennsylvanian time. Anhydrite and halite occur to 

the northwest, in Eagle Basin, and beds of gypsum have been reported 

in the area sampled.. The presence of saline springs in the vicinity of 

Salt Creek further suggests the occurrence of evaporite minerals in 

subsurface Pennsylvanian rocks.

The stratigraphy and nomenclature of Pennsylvanian rocks in central Colorado are coniplex and controversial. The name Belden Shale 

Member, as defined by Brill (1942), was applied to the lower member 

of his Battle Mountain Formation. He described the Belden as 100- 

200 feet of black and dark-gray carbonaceous shale and argillaceous 

limestone with thin beds of dark-colored sandstone overlying the 

Leadville Limestone in the vicinity of Oilman, Colo., and later raised 

the unit to formation rank (Brill, 1944). The coarser clastic rocks 

overlying the Belden were redefined and subdivided into the Minturn 

Formation and the Maroon Formation (Tweto, 1949). Chronic (1964, 

p. 109) indicated that in the southern part of the Mosquito Range the 

Belden Shale ranges in thickness from 500 to 3,000 feet. The variation 

in thickness of the Belden as reported by Brill and Chronic probably 

is partly due to the difficulty of defining a boundary, where no key beds 

have been traced, between the Belden Shale and the overlying Minturn 

Formation.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H5

The stratigraphic section near the Arkansas Biver was described by 

Brill (1952). In the text (p. 812) Brill stated that the Belden type of 

lithology extends from Eagle Basin on the north to Huerfano Park 

on the south, but in the detailed section (p. 864-879) he showed 4,200 

feet of Minturn Formation directly underlain by 157 feet of the Kerber Formation. Kerber Formation is the name applied to partly nonmarine basal Pennsylvanian strata in the Bonanza mining district of 

Saguache County, Colo. The samples collected for this study from the 

Arkansas River section include dark-colored shales and siltstones from 

the lower 280 feet of Pennsylvanian strata which are probably nearly 

equivalent to the Belden Shale but which may include some nonmarine 

beds.

HOTTY FORMATION FROM TEXAS

The Houy Formation samples from Texas, set 10, consist of 51 core 

samples of black shale and associated limestone and chert from the 

Houy Formation of Middle (?) Devonian to Early Mississippian age 

in Kendall County, Tex. (Cloud and others, 1957). Small samples 

were chipped from the core every few inches throughout an interval 

of 15 feet, representing the complete thickness of the Houy Formation 

and the overlying Chappel Limestone, about 3 feet thick.

The Doublehorn Shale Member of the Houy Formation is similar 

to, and probably in part equivalent to, the Chattanooga Shale of Tennessee, the Arkansas Novaculite in Arkansas, and the Woodf ord Chert 

in Oklahoma. The distribution of the Chattanooga Shale and its 

equivalents, including the Doublehorn Shale Member of the Houy Formation, is shown on a map by Conant and Swanson (1961, pi. 14). 

They infer a restricted epicontinental sea in Late Devonian and earliest Mississippian time that extended diagonally across the continent 

from Texas and New Mexico in the southwest to New York and Michigan in the northeast, and bounded by extensive land areas, including 

some, such as the Ozark highland, that extended well into the seaway. 

Except for deltaic sandstones in the Appalachian geosyncline, much 

of this sea was characterized by deposits of black shale and associated 

siliceous rocks. The Houy Formation was probably deposited in a local 

embayment in central Texas, adjacent to inferred land areas on the 

south, east, and northeast. Like many of the black shale units deposited during Late Devonian and earliest Mississippian time, the 

Houy Formation represents a relatively thin deposit for the time interval involved. Deposition probably occurred in quiet water on a shallow marine platform. An abundance of life in the sea is inferred 

because the supply of chemically or biologically precipitated mineral 

matter appears to have exceeded the supply of detrital mineral matter 

throughout much of the time.

329-580 69 2
H6 CONTRIBUTIONS TO GEOCHEMISTRY

Bioclastic carbonate rock occurs in the Chappel Limestone, and it 

also occurs in the upper part of the Doublehorn Shale Member of the 

Houy, which contains some fragments of brachiopods and crinoid 

stems largely replaced by pyrite. These units also contain scattered 1- 

to 2-cm nodules that may be coprolitic in origin. The nodules have an 

exterior rind of pyrite and an interior composed of radiolarian or 

other organic hash replaced by apatite. Conodonts also occur in black 

silty shale, but the most abundant fossils are the spore coats of Tasmanites, translucent yellow fragments of which occur throughout the 

shale. In cherty laminae, the Tasmanites are commonly preserved as 

spherical bodies with the interior cavity replaced with chalcedony. The 

inferred proximity to extensive land areas suggests that the organic 

matter in the Doublehorn Shale Member may also include a considerable amount of land-derived humic degradation products. This may 

account for the wide range in the appearance of the organic matter in 

thin sections of the shale. The organic matter, which contains many 

yellow objects, chiefly spore coats, is mostly opaque, but some is 

reddish brown.

CHEROKEE GROUP FROM KANSAS AND OKLAHOMA

The Cherokee Group samples from Kansas and Oklahoma, set 11, 

consist of 47 core samples of gray to black shale and siltstone and 

black phosphatic shale from four well cores through the Cherokee 

.Group in Greenwood County, Kans., and Osage and Craig Counties, 

Okla. Baker (1962), who provided these samples, distinguished three 

types of shale: (1) grayish-black to black carbonaceous clay shale 

which contains phosphatic nodules and marine fossils, including conodonts and inarticulate brachiopods; (2) greenish-gray to mediumgray nonfossiliferous clay shale; and (3) medium-dark-gray silty 

shale which contains coaly plant fragments. All three types of shale 

are probably shallow-water marine shelf deposits, and the color differences probably reflect differences in the amount of oxygen and organic matter available during sediment accumulation. In this set, each 

of 38 samples was split from the crushed core of a 3- to 5-foot-thick 

bed. Of these, 17 are of the first lithologic type, 17 are of the second 

type, and 4 are of the third type. The remaining nine samples in the 

set are composite samples that were prepared by mixing equal parts 

from the crushed core of several beds of the same type of lithology. 

Of these, four are of the first lithologic type, four are of the second 

type, and one is of the third type. Individual and composite samples 

were analyzed in the same manner and were given equal weight in the 

statistical treatment.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H7

Oil is recovered from shoestring sandstones in the Cherokee Group 

in this part of Kansas 'and Oklahoma. The Cherokee Group is a cyclic 

sequence that includes limestone, coal, and underclay, as well as sandstone and shale. The limestone beds contain marine fossils that probably represent the most northerly transgression of the sea on a broad 

shelf. The coal beds probably represent the most southerly regression 

of the sea. The shale beds probably represent shallow marine deposition intermediate in position between coal and limestone. The shoestring sandstones occur only locally and have been interpreted as 

river channels (Oadman, 1927) and as beach'bar deposits (Bass, 1936). 

Their shape and their stratigraphic position above shale indicate that 

they are more likely beach bar deposits. The Cherokee Group in this 

area ranges in thickness from about 265 to 375 feet and is correlative 

with rocks exposed to the east that range from the basal Pennsylvanian 

to the top of the Excello Formation of Searight and others (1953). As 

many as 18 individual formations, defined as all the strata from the 

top of one coal bed to the top of the next higher coal bed, have been 

recognized in scattered surface exposures, and many of these same units 

can be identified in the cores (Baker, 1962, p. 1627).

The samples in set 11 represent part of the same stratigraphic interval as the samples in set 5 (Vine, 1969), but they are different in that 

they are more variable in color and organic carbon content and are 

unweathered core samples instead of partly weathered outcrop samples. They also differ in that each bed was not subdivided into upper, 

middle, and lower parts as was commonly done in set 5. In general, 

these samples represent the noncarbonate fine-grained marine f acies of 

the intertonguing marine and nonmarine sequence of coal-bearing 

strata in the Pennsylvanian shelf area north of the Ouachita 

geosyncline.

The upper Paleozoic black shale samples from Arkansas and Oklahoma, set 12, consist of 30 outcrop samples of upper Paleozoic shale 

from Arkansas and Oklahoma. They include 20 samples of dark-gray 

to black shale and argillite from the Stanley Shale in Montgomery, 

Pulaski, Hot Spring, and Garland Counties, Ark.; seven samples of 

Atoka shale from Logan, Sebastian, and Scott Counties, Ark., and 

Pittsburg County, Okla,; two samples of black shale from the Arkansas Nbvaculite in Montgomery and Pulaski Counties, Ark.; and one 

sample of black shale from the Jackfork Sandstone in Perry County, 

Ark. These samples have much in common even though they are from 

several different formations. They are all taken from thick detrital 

sedimentary sequences deposited in the Ouachita geosyncline.
H8 CONTRIBUTIONS TO GEOCHEMISTRY

The Arkansas Novaculite, almost 1,000 feet thick, is chiefly siliceous 

mudstone (novaculite). The black shale samples from this formation 

were collected from the middle unit of Hass (1951), 347 feet thick, 

which contains abundant dark-colored shale interbedded with siliceous 

mudstone. This middle unit is regarded as the stratigraphic equivalent 

of the uppermost Devonian and lowest Mississippian Chattanooga 

Shale of Tennessee (Hass, 1951, p. 2536) and the Doublehorn Shale 

Member of the Houy Formation in Texas (Cloud and others, 1957, p. 

812). It is lithologically similar to the Doublehorn as described on 

pages H5, H6.

The Stanley Shale overlies the Arkansas Novaculite and consists of 

as much as 11,000 feet of dark-colored shale and siltstone. In many 

parts of the Ouachita Mountains the shales have been metamorphosed 

to argillite or slate, some of which is suitable for roofing material. 

Northwest of Little Kock, the upper part of the formation is considerably fractured and sheared so that bedding is obscure or lacking. The 

samples collected from this formation are chiefly medium-dark-gray 

to dark-gray silty shale or quartzose siltstone with variable amounts 

of clay minerals including illite and chlorite. Although the samples 

are dark, in thin section they show little opaque carbonaceous matter.

Some samples were collected at artificial exposures in the vicinity of 

barite deposits near the base of the Stanley Shale, but ore beds were 

not sampled. Because megafossils are sparse and poorly preserved in 

the Stanley, its age and stratigraphic correlatives have been the subject of controversy for some time. On the basis of conodonts from 

the lower part, however, Hass (1950) suggested that at least the lower 

part of the Stanley Shale may be of Mississippian age and correlative 

with the Caney Shale of Oklahoma and the Barnett Shale of central 

Texas. The Stanley Shale was probably deposited during a period of 

rapid downwarping of the Ouachita geosyncline, but there is little 

evidence other than the dark color to suggest environmental conditions 

at the time of deposition. Moreover, little information exists about the 

nature of the organisms that contributed to the accumulation of carbonaceous matter in the rocks.

The Jackfork Sandstone, which conformably overlies the Stanley 

Shale, consists of as much as 8,700 feet of sandstone and dark shale 

that probably represents a continued rapid downwarping of the 

Ouachita geosyncline and introduction of a greater proportion of 

coarse clastic material. The one sample of black shale from this formation was collected from a middle shale unit and is megascopically 

similar to many of the samples of Stanley Shale. The age of the Jackfork Sandstone, like that of the Stanley Shale, has been controversial 

partly because fossils are sparse and poorly preserved. Miser and
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H9

Hendricks (1960) reviewed the evidence, chiefly fossil plant material 

and field relationships, and concluded that the Jackfork Sandstone 

should be assigned a Mississippian age and that the overlying Johns 

Valley Shale should be assigned to both the Pennsylvania!! and Mississippian Systems.

The Atoka Formation of Middle Pennsylvanian age overlies the 

Johns Valley Shale of Mississippian and Pennsylvanian age in parts 

of western Arkansas and eastern Oklahoma. In other areas it lies on 

other named units of Early Pennsylvanian (Morrow) age. Reinemund 

and Danilchik (1957) described 11,800 feet of strata of the Atoka 

Formation in the Waldron quadrangle, Scott County, Ark., where the 

base is not exposed. They estimated that the Atoka may be as much 

as 19,000 feet thick locally in the Ouachita geosyncline. The Atoka 

thins rapidly northward and is not present in the outcrop area of southeastern Kansas, although it is represented by as much as 500 feet of 

strata in the subsurface of southwestern Kansas. The Atoka consists 

of dark-gray fissile clay shale with interbedded siltstone and sandstone. Most samples collected from this unit are dark-gray clay shale.

ANALYTICAL. METHODS

The analyses on which this report is based were done primarily by 

the routine six-step emission spectrographic method, which is similar 

to the three-step method described by Myers, Havens, and Dunton 

(1961). Results for the six-step method are identified with geometric 

intervals whose boundaries are 1.2,0.83,0.56,0.38,0.26,0.18,0.12,0.083, 

and so forth, and are arbitrarily reported as midpoints of these intervals, using the numbers 1, 0.7, 0.5, 0.3, 0.2, 0.15, 0.1, 0.07, and so forth. 

The precision of a reported value is approximately plus or minus one 

interval at 68-percent confidence, or two intervals at 95-percent confidence. Separate analyses were made for total carbon and carbon in 

carbonate minerals following the methods outlined by Tourtelot, Huffman, and Rader (1964, p. D74). Organic carbon was calculated by 

taking the difference between total carbon and mineral carbon. Several 

chemical analyses were made on samples from set 10, including SiO2 , 

A12O3 , Fe2O3 , MgO, CaO, Na2O, K2O, zinc, and sulfur. Silver and 

zinc were determined in samples of set 11 by atomic absorption 

analysis. .

STATISTICAL METHODS

Statistical analyses of the four sets of chemical data were conducted 

in the same manner as described in the previous reports (Vine, 1966, 

1969). The 5th, 25th, 50th, 75th, and 95th percentiles and the arithmetic and geometric means were calculated for each constituent, and the
H10 CONTRIBUTIONS TO GEOCHEMISTRY

product moment coefficient of correlation was calculated for each pair 

of constituents after first making a log transformation to place the 

data into a more nearly normal frequency distribution. Because the 

analyses commonly contain three types of indeterminate values 

(greater than, less than, and not detected), correlation coefficients 

were calculated after certain substitutions were made in the data 

sets (table 1).

The interpretation of geochemical associations in the rock units 

studied is based primarily on coefficients of correlation for each pair 

of constituents (tables 3, 5, 7, 9). The coefficients measure the degree 

to which log concentrations fit a straight line when plotted on a bivariate diagram, and the sign of the coefficient indicates whether the line of 

best fit has a positive or negative slope. If the bivariate frequency distribution does not deviate markedly from the normal form, and if the 

data can be regarded as a random sample from the rock units represented, the statistical significance of the coefficients may be determined 

from published tables of critical values (for example, Davies, 1954, p. 

276). Thus, in tables 4, 6, 8, and 10 are listed the more significant correlations for each element. These coefficients of correlation can be 

viewed as an index of geochemical associations among the samples 

analyzed even where the conditions for ideal sampling of the rock unit 

are not fully satisfied.

Groups of associated elements are further identified from the correlation matrices by the use of principal-component analysis. This 

technique, described by Harman (1960), has recently been applied1 to a 

variety of geologic problems. Some of these applications are described 

by Imbrie and Van Andel (1964) and by Griffiths (1966). The method 

involves constructing radial vectors for each chemical constituent such 

that the cosine of the angle between any two vectors is equal to the coefficient of correlation. The vectors are then rotated and projected onto 

a two-dimensional diagram on which the axes have been selected that 

will best represent most of the data in two dimensions.1 In these diagrams the relative lengths of the projected vectors are a function of 

how well each element is represented in the two-dimensional system. 

In the diagrams (figs. 2-5) the radial lines have been omitted for 

clarity, and only the position of the elements within a circle of unit 

radius is shown. The patterned segments of each diagram suggest possible geochemical groupings of the elements. The resulting groups 

of elements probably reflect different physical and chemical processes 

in the depositional environment and subsequent alteration of each rock

1 Examination of the eigenvalues of the correlation matrices, and of communalitles of 

variables on rotation Into more than two dimensions, has failed to reveal the presence 

of more than two principal components with any acceptable degree of certainty.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE Hll

TABLE 1. Substitutions made in the data sets 

[>, greater than; n.d., not detected; <, less than]

Element No. of 

samples

Reported as 

(percent)

Value substituted 

(percent)

Set 9 (43 samples)

A!., ------------ 28 >10 15

Fe-_____....._ ___..._ 1 >10 15

Ca_ 7 >10 15

K.___ -..._-_.___ 1 n.d. 1

B_......_.... ._. . 1 n.d. .0015

Be___________________ 2 n.d. .00005

Co... 1 n.d. .00003

La..___.__________._ 3 n.d. .0015

Pb___________._______ 8 n.d. .0003

Zr_____-.--.--______. 1 n.d. .0015

C«in - 7 <0. 01 .007

Set 10 (51 samples)

Fe-_ __ . 9 >10 15

Ca__________________ 10 >10 15

K__._ ........... -.-- 6 n.d. .5

Ag___________________ 21 n.d. .00005

B___________.-______ 25 n.d. .0005

Co.__.--_-.__------__ 1 n.d. .0003

Ga________________- 8 n.d. .0003

Ga___._ .___.___ 4 <0. 0007 .0005

La ___....._____ _ - . 16 n.d. .001

Mo____________-_-- - 4 n.d. .0002

Mo______ ______....._ 4 <0. 0005 .0003

Pb........... _ .... 5 - n.d. .0005

So_______.________._ 30 n.d. .00015

Tl___________________ 30 n.d. .0015

Y_________.__.____ 1 n.d. .0007

Yb._________________ 1 n.d. .00005

Yb-- __... ---. 14 <0.00015-0.0007 .00007

Zr__________________ 1 n.d. . 0015

Cow. 5 <0. 1 .07

Set 11 (47 camples)

Al___....______ _ 4 >10 15

Be ...... ...... . .-. 14 n.d. .0001

La__________________ 3 n.d. .0015

Mo . . . 27 n.d. .0002

Pb ........_ ............ 1 n.d. .0005

Set 12 (30 samples)

Na________.___ .__... 2 n.d. 0.02

K__. -.- 1 n.d. .5

B___________________ 3 n.d. .001

Be__________________ 2 n.d. .00007

Co__________________ 3 n.d. .0005

Ga________.______._ 2 n.d. .0005

La________.___. _ 2 n.d. .001

Nb.______._.__ _ 3 n.d. .0005

Pb.________________ 3 n.d. .0005

Sc_______ _. .. _ 1 n.d. .0002

Yb__.___...______ __ 1 <0.0003 .0002

Cmin. - _ - 3 <0.01 .005
H12 CONTRIBUTIONS TO GEOCHEMISTRY

unit. A factor complicating the interpretation of the groups, however, 

is that the data are part of a closed array. This problem, described by 

Chayes (1960), may be thought of as one of dilution. For example, 

consider major rock constituents such as detrital quartz, carbonate 

minerals, and clay. The end members of these three components may 

be regarded as pure siltstone, limestone, or shale containing only one 

of the three constituents. A built-in negative correlation must necessarily exist between a dominant major constituent and the other two 

principal constituents. A corresponding positive correlation is imposed 

on some of the minor constituents that results entirely from the dilution process. The process of dilution, therefore, is a factor affecting 

the magnitude of any of the correlation coefficients in tables'3, 5, 7, 

and 9-. ......

DISTRIBUTION OF ELEMENTS

The distribution of elements is described separately for each of the 

four sets of samples because each set is different in lithology: the 

stratigraphic units represented by the four sets accumulated in different environments of deposition, and each was sampled according to 

different sampling patterns. The concentrations of each element or 

constituent are listed by percentiles in table 2, and coefficients of correlation that were calculated for each pair of constituents for each 

sample set are listed in tables 3, 5, 7 and 9. Where less than half ^of 

the values are listed as indeterminate values (greater than, less than, 

not, detected), it is possible to 'give the median and some of the 

percentiles. .......

TABLE, 2. Element concentration in four sets of Paleozoic black shale samples

[Chemical analyses were made to determine SiOj, AhOa, FejOa, MgO, CaO, NajO, KjO, Zn,and S for set

-10; Ag, and Zn-for set 11. All other analyses except carbon were made by the six-step spectrographic method.

Total carbon was determined by induction-furnace method, mineral carbon by acid extraction, and organic

carbon was calculated by. difference. Parentheses indicate content of element recalculated to the elemental

form. See p. H2.H9 for discussion and list of analysts]

Element or 

constituent

Si

SiOj- 

/Qi\

AL.... ..

AljOs.. . ( \n

AL. .........

AL. ..........

Fe - . Fe... ..... . ...

Fe..... . Ms

(Me) .

9

... 10

9

... 10

... 11

... 12

9

... 10

... 11

... 12

9

... 10

Values, in percent, for indicated pefcentile

Ps

5. 0 

19.4 

.(9-0) ...

3

1.27 

(.68) 

5 

2.

2.' '. 

1.5 

(1.0) 

2 .

.7

1

.30 

(.18)

P25

MO.-O 

36.4 

(17) .

7 

3.02 

(1.6) 

7

2 

5.61 

(3.9) 

3 

3

1.5 

1.24 

(.75)

Pso

>10.0 

45.6 . 

. (21).

4.36 

(2.3) 

7

3

9. 60 

(6. 7) 

3 

5

2 

2.06 

(1.2)

P7S .

>10.0 

69.0 

(32)

5. 44 

- (2.9) '

 -7

3

13; 1

. (9.2) . 

5 

5

3

3.78 

(2.3) '

..P»5

>10;0 

93.0 

(43)

8.41 

(4.5)

5 

19. 8 

(14) 

5 

5

..5 . 

5.74 

' (3. 5)

Arith-' 

metic 

mean

50.3 

(23)

4.6 

(2.4)

7.2

3.3

10 

. (7. 0) . 

3.6 

3.8

. . 2. 6 . 

2.6 

" (1. 6>

Geometric 

mean 

48.6 

.(23)

4.1 

7il

2:9 . 8.0 

(5.6) 

3. 4^

2..3 ' 

2.0 

fl. 2^
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H13 

TABLE 2. Element concentration in four sets of Paleozoic black shale samples Con.

Element or 

constituent

Mg.... ........

Mg...... ......

Ca.... ........

CaO. .........

. '(Ca)......

Ca..... .......

Ca... .........

Na..... .......

NasO. ........

(Na)......

Na............

Na..... .......

K.... .........

KsO. ...... .-

 JJ 

K............

Mn. .........

Ctot.l--.. -

Aff

B............

Ba...-. ......

Be...........

Co...........

Cr...........

Set -

... 11

12

.:. 9

... 10

... 11

... 12

9

... 10

... 11

... 12

9

... 10

... 11

... 12

9

10 

11 

12

9

10 

11

12

9

10 

11 

12

9

10 

11 

12

9

10 

11 

12

... 10

11

9

10 

11 

12

, _ 9

10 

11 

12

9

' 10 

, 11 

12

... 9

10 

11 

12

9

10 

11 

12

Values, in percent, for indicated percentile

Pt

0.5 

.2

.3

.64 

. (.46) 

.15 

.007

.1 

.11 

(.08) 

1 

<.05

2 

.32 

(.27) 

2 

1

.07 

.03 

.1 

.15

.007 

.005 

.015 

.0015

.25 

1.44 

' .67 

.16

.'25 

.03

.02

!e " .2

<.0001 

.0002

.003

. .'003 

<.002

.01 

.005 

.015 

.02

<.0001 

<.0001 

<.0002 

<. 00015

.0005 

.0007 , 

.001 

<.001

.005 

.0005 

.01 

.007

Pas

0.7

.7

.7 

2.19 

(1.6) 

.2 

.03

.7 

.22 

(. 16) 

1 

.3

3

1.06 

(.88) 

3 

3

.2 

.07 

.2 

.3

.015 

.01 

.03 

.015

.88 

 3.65 

1.86 

.42

.02 

.52 

.24 

.03

.05 

1.3 

1.4

.4

<.0001 

.0003

.007 

 C.OOl 

.005 

.003

.02 

.007 

.02 

.03

.0002 

<.0001 

<.0002 

.0002

.001 

..003 

" ".0015 

.001

.01 

.002 

.01 

.01

P»

0.7 

.7

1.5 

5.04 

(3.6) 

.3 

.07

1 

.27 

(.20) 

1.5 

1

5 

1.62 

(1.3) 

3 

3

.2 

.1 

.2 

.3

.03 

.03 

.05 

.03

2.3 

7.06 

3.60 

.91

.72 

1.63 

.55 

.05

1.3 

5.0 

3.2 

.6

.0001 

.0004

.015 

.001 

.005 

.003

.03 

.015 

.03 

.05

.0003 

 COOOl 

.0002 

.0002

.001 

.01 . 

.002 

.0015

.01 

.003 

.015 

.01

P7S

1 

1

7 

9.79 

(7.0) 

5 

.15

1 

.36

(.27) 

1.5 

1.5

5 

2.04 

(1.7) 

3 

3

.3 

.15 

.3 

.3

.1

' .07 

.07 

.05

5.0 

8.83 

11.00 

1.43

3.2 

2.60 

.83 -.09

2 

7.1 

10.2 

1.0

.0002 

.0005

.02 

.002 

.005 

.007

.05 

.02 

.03 

.07

.0005 

<.0001 

.0002 

.0002

.0015 

.02 

.002 

.0015

.01 

.005 

.03 

.015

P»5

1.5 

1.5

30.2 

(22)

.3

2 

.48 

(.36) 

1.5 

2

7 

3.12 

(2.6) 

3 

3

.3 

.2 

.3 

.5

.15 

.1 

.1 

.1

7.7 

14.21 

14.80 

2.70

5.8 

6.99 

1.15 

' .69

2.7 

12/5 

14.1 

1.8

.0002 

.0006

.03 

.007 

.007 

.01

.07 

.03 

.05 

.15

.0007 

.0003 ..

.0002 

.0003

 .002 

.03 

.003 

.002

.015 

.015 

.07 

.02

Arith- Geometric 

metic -mean 

mean

0.80 

.78

4.8 

7.4 

(5.3) 

2.0 

.22

.90 

.29 

(-21) 

1.3 

1.0

4.0 

1.6 

(1.3) 

2.9 

2.8

.24 

.12 

.24 

.31

.10 

.039 

.046 

.044

3.2 

7.1 

6.2 

1.3

1.8

2.0 

.59 

.16

1.3 

5.1 

5.6 

1.1

. 00012 

.00037

.013 

.0022 

.0054 

.0039

.033 

.015 

.027 

.071

.00034

. . 00017 

 . 00018-

.0011 

.014 

. 0019 " ' 

.0014

.0099 

.0055 

.026 

.012

0.77 

.69

3.5 

4.6 

(3.3) 

.76 

.067

.75 

.27 

(-20) 

1.3 

.65

3.7 

1.4 

(1.2) 

2.9

2.7

.22 

.10 

.23 

.29

.04 

.030 

.040 

.027

2.2 

5.8 

4.1 

.83

.35 

1.3 

.43 

.062

1.0 

2.6 

3.4

.72

.00009 

.00034

.011 

.001 

.0053 

.0033

.029 

.010 

.026 

.054

.00031

.00016 

.00017

-.0010 

.0080 

.0018 

.0013

.0096 

.0030 

.020 

.011

329-580 69-
H14 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 2. -Element concentration in four sets of Paleozoic black shale samples Con.

Element or 

constituent Set

Values, in percent, for indicated perceutile

Pss P75 P«J

Arith-. Geometric 

metic mean 

mean

Cu - .90.0007 0.002 0.003

10 .005 .015 .02

11 .003 .007 .01

12 .002 .003 .005

Ga . .9 .001 .002 .003

10 <.0005 .0005 .0007

11 .002 .003 .003

12 <.001 .003 .003

La- ........ 9 <.003 .005 .007

10 .001 .001 .003

11 <.003 .003 .003

12 <.002 .002 .003

Mo . . 10 <.0005 .0005 .007

11 <.0005 <.0005 <.0005

Ni ... 9 .002 .003 .003

10 .005 .02 .05

11 .002 .005 .005

12 .002 .005 .005

Pb ..... 9 .0007 .0007 .0015

10 .0005 .003 .005

11 .001 .002 .002

12 .001 .0015 .002

Sc 9 -001 .002 .002

10 <.0003 <.0003 <.0003

11 .0007 .001 .001

12 .0005 .001 .0015

Sr.

Yb.

Zn. 

Zr.

9

10

11

12

9

10

11

12

9

10

11

12

.005

.0015

.02

.003

.005

.005

.007

.015

.002

.001

.002

.0015

9 <.00015

10 <.0003

11 <.0002

12 <.0003

TL.......

8.........

Nb.. ....

10

11

9

10

11

12

10

10

12

.012

.0063

.003

.003

.003

.003

<.003

.20

<.001

.015

.007

.02

.007

.01 

.01 

.01

.02

.003

.002

.002

.002

.0003 

<.0003 

<.0002

.0003

.037

.083

.005

.005

.005

.007

<.003

2.65

.001

.015 

.02 

.03 

.01

.01

.015

.015

.02

.005

.003

.003

.003

.0003

.0003

<.0002

.0003

.090

.014

.007

.007

.005

.01

<.003 

6.73 

.001

0.005

.03

.015

.005

,005

.001

.005

.005

.01

.007

.005

.003

.015

,0015

.005

.07

.015

.005

.003

.007

.007

.002

.003 

.0007 

.0015 

.0015

.02 

.03 

.05 

.015

.015 

.02 

.03 

.02

.005

.007

.003

.003

.0005

.0005

.0003

.0003

.12 

.076

.01 

.01 

.007 

.01

.005

9.78

.0015

0.01 

.05 

.02 

.01

.005

.0015

.005

.005

.015

.01

.005

.005

.015

.003

.007 

.1 

.02 

.007

.01

.015

.01

.005

.003

.001

.0015

.0015

.07 

.05 

.05 

.02

.015 

.05 

.05 

.03

.005

.01

.005

.005

.0005

.001

.0003

.0003

.24 

.23

.02

.02

.015

.015

.007

13.89

.0015

0.0040

.021

.013

.0047

.0031

.00074

.0035

.0037

.0073

.0048

.0036

.0030

.0076

.0039

.049

.010

.0048

.0026

.0052

.0046

.0021

.0023

0.0031

.020

.0098

.0042

'..0028 

.00070 

.0033 

.0032

.0064

.0033

.0034

.0027

.0040

.00048

.0035

.030

.0079

.0045

.0015

.0040

.0033

.0019

.0072

.0012

.0012

.021

.023

.033

.016

.011

.021

.022

.021

.0040

.0049

.0028

.0024

.0011

.0012

.016

.020

.030

.011

.011

.020

.017

.020

.0037

.0040

.0026

.0023

.00041

"Voooso"

.092

.050

.0077

.0094

.0063

.0087

.0031

6.7

.0013

.00020 "."66629

.070

.024

.0068 

.00?0 

.0058 

.0079

.0030

4.5

.0012
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE HI5 

BELDEN SHALE FROM COLORADO

Major elements. The major elements in the Belden Shale (set 9), 

in order of decreasing abundance, are silicon, aluminum, potassium, 

iron, magnesium, calcium, sodium, and titanium. Of the 43 samples 

studied, 40 contained 10 percent or more of silicon, and more than 

half contained 10 percent or more of aluminum. Although many of 

the samples are dark gray to black, the total carbon content is low 

in comparison with that in many black shales. The range of mineral 

carbon content is greater than that of organic carbon, but the total 

carbon content is rather evenly divided between the two types in. 

many samples:

Minor elements. The median concentrations of most of the minor 

elements are not unusual, but at the 95th percentile, boron, beryllium, 

gallium, and lead contents are high in comparison with those in the 

other black shales that have been studied. Moreover, lithium was reported to occur in 36 of the 43 samples in set 9, although no attempt 

was made to determine the amount quantitatively. This suite of minor 

elements may reflect the nature of the granitic terrain from which the 

sediments were derived, for Precambrian rocks with similar traceelement suites have been reported from a nearby area of the ancestral 

Rocky Mountains (Hawley and others, 1966).

Element associations. The correlations and associations shown in 

tables 3 and 4 for the Belden Shale can be used to divide the elements 

into four groups, as shown on the vector diagram (fig. 2). Organic 

carbon and mineral carbon occur in the same segment of the diagram, 

but only mineral carbon is well represented. Lead and copper may be 

partly associated with the organic carbon, but they are also poorly 

represented. Calcium, magnesium, and manganese seem to be chiefly 

associated with carbonate minerals, whereas strontium seems to correlate with both carbonate minerals and organic carbon. The second 

group, which consists of aluminum, titanium, vanadium, lanthanum, 

scandium, gallium, chromium, barium, and cobalt, is probably detrital 

in origin and mode of occurrence, and it seems to be inversely related
H16 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 3. Coefficients of correlation for element pairs in

Al Fe Mg Ca Na

Al -0.01-0.10 -0.52 0.35

Fe -.13 -.14 -.31

Mg .57 .17

Ca -.02

Na

K

0.33 

-.26 

.36 

.02 

.42

K

Ti

0.64 

.05 

-.32 

-.71 

.38 

.06

Ti

Mn

0.54 

.20 

.59 

.79 

-.26 

-.05 

-.67

Ma 

Significance level, 41 degrees of freedom

95 "percent 99 percent

0.30 0.39

99.9 percent

0.49

B

0.27 

-.29 

.41 

.01 

.42 

.80 

.07 

-.02

B

Ba

0.46 

.14 

-.11 

-.26 

.35 

.11 

.52 

-.26 

.03

Ba

Be

0.42 

-.27 

.36 

.14 

.41 

.52 

.23 

-.01 

.60 

.31

Be

Co

0.44 

.38 

.09 

-.33 

.09 

.34 

.28 

-.09 

.34 

.22 

.16

Co

Cr

0.62 

-.19 

-.09 

-.38 

.41 

.21 

.56 

-.52 

.31 

.37 

.38 

.24

Cr

Cu

0.12 

-.27 

.23 

.22 

.08 

.27 

-.10 

.24 

.23 

-.12 

.19 

..25 

.15

Cu

 Ct, total carbon. 

2 Core, organic carbon. 

8 C m in, carbonate carbon.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H17

set 9, 43 samples of Belden Shale from Colorado

Ga

0.68

.26

-.27

-.69

.22

.32

.65

-.48

.16

.35

.10

.47

.32

.08

Oa

La

0.62

.02

-.09

-.56

.36

.60

.57

-.44

.55

.32

.31

.62

.37

.09

.61

La

Ni

0.18

.07

.36

.04

.09

.17

.06

.19

.19

.13

.20

.36

.26

.05

-.01

.23

Ni

Pb

-0.09

.21

.09

.19

-.22

.03

-.19

.33

-.01

-.21

.00

.18

-.03

.52

.02

.01

-.03

Pb

Sc

0.60

.27

-.32

-.63

.42

.29

.70

-.54

.37

.40

.33

.41

.47

-.10

.68

.69

-.01

.02

Sc

Sr

-0.27

-.29

.04

.49

.40

.02

-.10

.15

-.02

.04

.13

-.27

-.07

.16

-.17

-.25

-.39

.00

-.12

8r

V

0.72

.04

.04

-.52

.42

.41

.63

-.48

.42

.31

.46

.49

.58

.13

.55

.61

.17

-.03

.66

-.16

V

Y

0.03

.17

.31

.18

.18

.32

.04

.30

.42

.18

.46

.11

-.02

-.12

-.04

.30

.39

.16

.32

-.13

.04

Y

Zr

-0.19

.65

-.29

-.10

-.47

-.48

-.02

.18

-.54

.10

-.34

.12

-.21

-.24

.02

-.20

.10

.22

.03

-.27

-.35

.21

., Zrc,»

-0.61

-.26

.41

.84

.01

.09

-.64

.70

.02

-.36

.08

-.26

-.38

.45

-.55

-.44

-.10

.32

-.66

.55

-.45

.04

-!20

C»

Co,,1

-0.09

-.13

-.04

.34

.04

.01

-.17

.24

-.11

-.18

.04

.03

-.02

.61

-.16

-.08

-.11

.47

-.19

.41

-.12

-.15

-.09

.69

Corf

Cml n«

-0.52

-.23

.64

.88

-.01

.14

-.68

.76

.14

-.32

.16

-.24

-.41

.18

-.53

-.46

-.03

.17

-.61

.44

-,47

.18

-.15

.77

'.22

Cmln
HIS CONTRIBUTIONS TO GEOCHEMISTRY

FIGURE 2. Rotated two-dimensional vector diagram of the principal-component 

analysis of the correlation matrix for set 9, 43 samples of Belden Shale from 

Colorado. Patterned areas suggest geochemical groupings of elements.

to the mineral carbon and organic carbon group. Zirconium and iron, 

which make up the third group, show a fairly strong association with 

each other but not with any of the other elements. They may represent 

a heavy detrital mineral group. The fourth group, which consists of 

potassium, sodium, beryllium, and boron, has a negative correlation 

with the iron and zirconium group, but its origin and mineral composition are uncertain. It may represent a light detrital fraction that 

would include feldspars.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H19

TABLE 4. Element associations in set 9, 43 samples of Belden Shale from Colorado

[Elements are listed In order of Increasing correlation coefficients. Regular type used where the level of 

significance exceeds 95 percent; boldface type where the level of significance exceeds 99 percent]

Negative Correlation «-

Ti, Sc, Ga, AI, V, La, Cr, Ba

Ti, Sc, Ga, La, V, AI, Cr, Co

Ti, AI. Sc, Cr, Ga, V, La

Sc.Ti

Ni

Na

B, K, Na, V, Be

Sr

Zr

Ca

Zr

Zr

Cmin

Zr, Fe

Ca, Mn, Cmin, Zr

Ca, Cmin, Mn, Mg

Ca, Cmin, Mn, Mg

Ca, Cmin. Mn

Ca, Cmin, Mn

Mn, Cmin, Ca

Mn, Ca, Cmiu

Element

Cn,in

Ca

Mn

Mg

Sr

Co,*

Cu

Pb

Fe

Zr

Ni

Y

B

Co

Be

K

Ba

Na

V

Sc

Ti

Ga

La

Cr

AI

-» Positive Correlation

Sr, Mg, Mn, Ca

Con, Sr, Mg, Mn, Cm in

Y, Pb, Mg, Cmin, Ca

Y, Ni, Be, K, B, Ca, Mn, Cmin

Na, Cor«, Cmin, Ca

Ca, Sr, Pb, Cu

Pb. Con

Mn, C0r«, Cu

Co, Zr

Fe

Co, Mg, Y

La, Mn, Mg, Sc, K, Ni, B. Be

Cr, Co, Sc, Mg, Y, V, Na, La, Be, K

B, K, Ni, Fe, Sc, AI, Ga, V, La

La, Ba, Sc, Mg, Cr, Na, AI. V, Y, K, B

Y, Ga, AI, Co, Mg, V, Na, La, Be, B

V, Be, La, Na, Ga, Cr, Sc, AI, Ti

Ba, La, AI, Ti, Sr, B, Be. Cr, Sc, V, K

Ba, K, B, Na, Be, Co, Ga, Cr, La, Ti, Sc. AI

Y, Be, B, Ba. Co, Na, Cr, AI, V, Ga, La. Ti

Na, Ba, Cr, La, V, AI, Ga, Sc

K, Cr, Ba, Co, V, AI, La, Ti, Sc

Y, Be, Ba, Na, Cr, K, B, Ti, Ga, V, Co. AI, Sc

B, Ga, Ba, La, Be, Na, Sc, Ti, V ,AI

K, Na, Be, Co, Ba, Ga. Sc, La, Cr, Ti, V

HOUY FORMATION FROM TEXAS

Major elements. The most abundant constituent in samples of the 

Houy Formation (set 10) is SiO2 , which has a median value of 45.6 

percent and a 95th percentile of 93.0 percent. About a quarter of the 

samples are siliceous enough to be classified as black chert. The next 

most abundant constituents are I^Oa and sulfur, which together reflect the abundance of pyrite nodules and disseminations in the Houy. 

The amount of pyrite in these samples greatly exceeds that of any 

other set of black shale samples that have been studied. If most of the 

iron and sulfur are combined in the form of pyrite, at the median 

level more than 12 percent pyrite may be present. Five percent of 

the samples contain more than 25 percent pyrite. Carbon is also 

abundant and has a median value of 7 percent. Of this, organic carbon 

is more abundant and more widely dispersed than mineral carbon.
H20 CONTRIBUTIONS TO GEOCHEMISTRY

The next most abundant constituent is CaO, which has a median value 

of 5 percent, followed by MgO, which has a median value of 2 percent, reflecting the fact that some of the samples contain abundant 

calcite and dolomite. The contents of A12O3 , K2O, and titanium are 

relatively low because of the abundance of chert, carbonate, and organic 

matter. As much as 3 percent phosphorus was also detected in a few 

samples.

Minor elements. Many minor elements are unusually abundant in 

the core samples of the Houy Formation. Previous analyses of rocks 

from the Houy Formation, reported by Tourtelot (1956, p. 76) and 

Swanson (1960, p. 38), suggested this possibility. The median concentrations of cobalt, copper, molybdenum, nickel, lead, and zinc are 

several times the average concentrations for shale as estimated by 

Turekian and Wedepohl (1961, table 2), and at the 95th percentile 

concentrations of most of these elements are remarkably high. Thallium was also reported in 21 of the 51 samples and is about 50 times as 

abundant at the 95th percentile as in the average shale. All these 

elements are sulfophile, and, therefore, their enrichment in these 

rocks may be related to the unusually high pyrite content. Thallium 

and zinc, in particular, show a greater concentration in a pyriterich heavy-mineral separation prepared from one of the black shale 

samples. The median contents of detrital elements like boron, gallium, 

and scandium are less than those in most of the other black shale 

sets previously studied. Other minor elements are present in nearly 

normal amounts.

Element associations. The diluting effect of SiO2 , contained in 

both detrital quartz and chert, has a pronounced effect on the correlations between other elements in the samples.of the Huoy Formation 

(tables 5 and 6; fig. 3). The strong negative correlation between SiO2 , 

and most other elements increases the tendency of the other elements to 

correlate positively with each other. However, it is possible to divide 

most of the elements into several major groups. Mineral carbon correlates best with CaO, manganese, strontium, and MgO, but these 

constituents overlap the segment of the vector diagram (fig. 3) that is 

occupied by the detrital elements. Organic carbon shows its strongest 

correlation with molybdenum; it also shows strong positive correlations with silver, nickel, zinc, cobalt, copper, and thallium. These 

elements correlate about equally well with sulfur, as indicated by 

their position in figure 3 intermediate between organic carbon and
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H21

FIGURE 3. Rotated two-dimensional vector diagram of the principal-component 

analysis of the correlation matrix for set 10, 51 core samples of the Houy 

Formation from Texas. Patterned areas suggest geochemical groupings of 

elements.

sulfur. Sulfur also shows a very strong correlation with Fe2 03 and 

lead. The sulfur and organic carbon groups are probably very closely 

associated. The detrital group includes most of the remaining elements and oxides: A1208 , K2 0, Na2 0, titanium, gallium, zirconium, 

chromium, lanthanum, yttrium, barium, and vanadium. Scandium 

and ytterbium seem to be weakly associated with the detrital group 

of elements (fig. 3). Boron seems to vary almost independently of 

all other elements, although the correlation estimates may not be entirely reliable because of the large number of substitutions for indeterminate values.
H22 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 5. Coefficients of correlation for element pairs in

Ti

Ti

Mn

0.22

Mn

Ag

0.08 

.25

Ag

B

0.34 

-.57 

-.36

B

Ba

0.69 

.47 

.39 

-.09

Ba

Co

0.19 

.27 

.68 

-.34 

.32

Co

Cr

0.86 

.19 

-.06 

.43 

.50 

-.04

Cr

Cu

0.43 

.40 

.51 

-.29 

.42 

.70 

.17

Cu

Ga

0.70 

.34 

.24 

.17 

.62 

.14 

.72 

.38

Ga

La

0.68 

.51 

.26 

-.08 

.82 

.32 

.52 

.36 

.55

La

Mo

-0.11 

-.16 

.64 

-.14 

.04 

.65 

-.29 

.48 

-.04 

-.13

Mo

Ni

0.28 

.23 

.65 

-.23 

.39 

.87 

.04 

.74 

.20 

.38 

.69

Ni

Pb

0.29 

.47 

.33 

-.43 

.39 

.61 

.11 

.70 

.23 

.44 

.09 

.55

Pb

Sc

0.63 

-.03

-.27 

.57 

.22 

-.09 

.72 

-.08 

.45 

.40 

-.31 

-.02 

.05 

SC

Sr

0.80 

.58 

.24 

-.05 

.75 

.37 

.72 

.44 

.62 

.83 

-.16 

.39 

.56 

.49

Sr

TI

0.27 

.26 

.68 

-.22 

.44 

.67 

.04 

.47 

.19 

.39 

.60 

.61 

.27 

.01 

. 32

Significance level, 49 degrees of freedom

95 percent

0.28

99 percent

0.36

99.9 percent

0.45

TI

1 Ct, total carbon.

2 (.'on-, organic carbon,

3 Cmin, carbonate carbon.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H23

 set 10, 51 core samples of the Houy Formation from Texas

V

0.66

-.01

-.12

.34

.26

.13

.63

.44

.46.

.28

-.09

.18

.46

.59

.49

' .00

V

Y

0.72

.53

.15

-.02

.77

.21

.61

.39

.60

.86

-.21

.30

.51

.42

.85

.26

.41

Y

Yb

0.33

.36

-.13

-.03

.40

-.14

.28

.22

.34

.33

-.47

-.10

.23

.03

.34

-.27

.20

.38

Yb

Zr

0.70

.54

.40

-.14

.84

.44

.46

.61

.61

.74

.16

.52

.41

.19

.71

.50

.26

.71

.35

Zr

Zn

0.34

.24

.67

-.23

.40

.83

.13

.89

.35

.28

.72

.86

.56

-.09

.37

.59

.34

.30

-.01

.57

Zn

Ct>

0.35

.30

.57

-.20

.25

.75

.25

.74

.25

.19

.63

.75

.45

.00

.42

.63

.31

.20

-.17

.41

' .79

c,

Cor.'

0.07

-.31

.57

.08

.10

.52

-.05

.43

.06

-.10

.88

.60

.00

-.22

-.10

.55

.01

-.15

-.44

.14

.64

.63

Cori

CIO !n«

0.35

.88

.26

-.46

.51

.28

.36

.39

.46

.49

-.15

.26

.44

.07

.08

.20

.12

.63

.38

.56

.28

.41

-.27

Cmin

S

0.34

.34

.41

-.23

.35

.66

.13

.69

.19

.47

.32

.76

.73

.08

.51

.46

.36

.44

.00

.39

.60

.63

.32

.30

S

SiOj

-0.49

-.67

-.19

.25

-.42

-.46

-.41

-.40

-.32

-.64

.17

-.39

-.60

-.43

-.78

-.39

-.32

-.60

-.15

-.49

-.27

-.47

.25

-.71

-.54

SiOj

AlzOj

0.81

.02

.30

.39

.69

.29

.74

.38

.76

.59

.17

.34

.22

.54

.63

.40

.57

.56

.11

.63

.45

.34

.35

.14

.28

-.27

AhOj

Fe:0i

0.64

.37

.44

-.15

.55

.70

.38

.79

.45

.60

'.29

.70

.76

.27

.71

.54

.56

.63

.11

.66

.73

.65

.29

.38

.79

-.63

.58

FeaOi

MgO

0.51

.7.0"

.54

-.42

.69

.61

.34

.73

.56

.57

.24

.55

.59

-.04

.70

.50

.29

.61

.31

.75

.65

.63

.18

.77

.55

-.54

.43

.71

MgO

CaO

0.46

- .78

.09

-.31

.53

.16

.52

.24

.45

.61

-.40

.14

.50

.29

.81

.05

.24

.69

.41

.47

.11

.24

-.40

.87

.32

-.77

.23

.40

.61

CaO

N8lO

0.78

.47

.35

-.03

.82

.28

.69

.59

.74

.69

.07

.43

.37

.27

.76

.33

.44

.75

.42

.83

.55

.42

.20

.53

.36

-.38

.74

.62

.75

.55

NaaO

KaO

0.82

.17

.36

.17

.76

.36

.73

.44

.74

.67

.14

.39

.39

.50

.77

.45

.57

.65

.13

.69

.48

.42

.28

.32

.39

-.42

.93

.68

.60

.40

.76

KiO
H24

TABLE 6. Element associations in set 10, 51 core samples of the Houy Formation

from Texas

[Elements are listed in order of increasing correlation coefficients. Regular type used where the level of 

significance exceeds 95 percent; boldface type, where the level of significance exceeds 99 percent]

Negative Correlation* Element - Positive Correlation

SiOi, B

SiOj, Core, Mo, B

SiOs, B, Con

SiOj

B

Yb, CaO, Sc, Cr

Yb, CaO, Mn

SiOj

SiOj, B

8iO2, B

SiOj

SiOa, B 

SiOj

Sr, CaO, Cm ID, Mn, La, FejOs, Y,

Pb, MgO. S. Zr, Ti, Co, Sc, KjO,

Ba, Cr, Cn. Tl, Ni, NajO, V, Ga

Mn, Cmh. Pb. MgO, Ag, Co, CaO,

Cu

SiO2, Mo 

SiOj

Mo, Con

SiOj

SiO>

SiOj

SiO2 , B

CaO

Mn

Tl

Ag

Mo 

Cor* 

Ni

Zn 

Cu 

Pb 

FejOs

Co

8

SiOj

Sc 

V

Yb

Y

La

Ba

MgO

Co, Zn, S, K2O, Ti, Cr, Yb, Fe2O3, Cu, Pb, Ga, La, Ba,

Na2O, Y, Zr, Sr, MgO, CaO, Mn 

Sc, S, K2 0, FeaOs, Yb, Ga, Ti, Zr, Pb, Ba, Cr, NaiO, La,

MgO, Y, Mn, Sr, Cm | 0 

Ga, S, Yb, Fe2O3 , Cu, Ba, Pb, NajO, La, Y, Zr, Sr, MgO,

CaO, Cnin 

Sr, Na2 0, La, AlsO3 , Ba, KjO, S, Cu, MgO, Zr, FejOi,

Corg, Zn, Mo, Ni, Co, Ag 

Ala03 , Pb, NajO, KjO, Ba, Zr, S, FejOa, Cu, MgO,

Corg, Mo, Ni, Zn, Co, Tl 

Fea03 , S, Cu, Tl, Ag, Co, Ni, Zn, Corg 

KaO, FeaOs, AljOa, S, Cu, Co, Tl, Ag, Ni, Zn, Mo 

Ti, Y, Ala0 3 , La, Ba, Sr, KjO, Na»O, Zr, Pb, MgO,

Corg, Tl, Ag, Mo, Fe2O3, Cu, S, Zn, Co 

Cmin, La, Y, Ti, V, Ga, Sr, Ba, AljO3, KjO, NajO, Pb,

Zr, Tl, S, Cptg, MgO, Ag, Mo, FejOs, Co, Ni, Cu 

La, Ga, A12O3> Cm in, Y, Mn, Ba, Ti, Corg, Sr, KjO. V,

Tl, Mo, Ag, Na2O, Zr, S, Co, Pb, Ni, FeaOs, Zn 

Ti, Ag, NajO, Ba, KjO, Zr, La, Cmin, V, Mn, CaO, Y,

Ni, Sr. Zn, MgO, Co, Cu, S, FesOi 

Cotg, Mo, Mn, Cr, Cmin, CaO, Ag, Ga, Tl, Ba, V, AhOa,

La, Na2O, Y, Ti, Zr, K2O, Ni, Co, Sr, MgO, Zn, Pb,

Cu, S 

Cmin, NaaO, AlaOa, Ba, La, KjO, Sr, Zr, MgO, Corg,

Pb, Mo, S, Tl, Ag, Co, FejO., Zn, Ni 

A12O3 , Cmin, Corg, CaO, Mo, Ti, Mn, Ba, NaiO, V,

K2O, Zr, Ag, Y Tl, La, Sr, MgO, Zn, Co, Cu, Pb,

Ni, FejO3

Ti, V, AhOa, Cr, Sc

CaO, La, Y, Ga, Sr, KjO, AlaO., B, V, Ti, Cr

La, MgO, B, Zn, S, Y, Cu, Na2O, Ga, Pb, Sr, FeiOi,

AIjOs, KiO, Sc, Cr, Ti 

Cr, MgO, Ti, La, Ga, Sr, Zr, Mn, Y, Cmi a , Ba, CaO.

NajO 

Ni, Zn, Yb, Cu, V, Sc, S, Pb, Mn, Cmin, AliOi, Ga,

Cr, MgO, FeaOs, KjO, CaO, Zr, Ti, NaiO, Ba, La 

V, Zn, Co, Yb, Cu, Ni, Tl, Sc, Pb, S, Cmin, Mn, Cr,

Ga, MgO, A12O3 , FejO3 , CaO, KSO, Ti, NaiO, Zr, Ba, Y 

Co, S, Ag. Ni, Pb, Yb, Zn, Cu, Tl, Mn, Cr, Cmin, CaO,

FeaOs, Ga, Ti, AlaOj, MgO, Sr, KaO, Y, NajO, La, Zr 

V, Yb, Cr, A12O3 , Tl, Ti, Co, Ag, Ni, S, Ga, La, Pb,

K2O, CaO, Y, Zn, Ba, Sr, Mn, FeaO,, Cu, NajO, Zr,

Cmin
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H25

TABLE 6. Element associations in set 10, 51 core samples of the Houy Formation

from Texas Continued

Negative Correlation«-

Si08

SiOa

SiOj, Mo

SiOs

SiOj

SiOi

SiOj

Element

Sr 

Ti

Cr

KjO

NajO

Zr

Ga

AlsOs

-»Positive Correlation

Tl, Yb, Co, Zn, Ni, Cu, Sc, V, S, Pb, Mn, Ga, AIjOi,

Cmin, MgO, FejOa, Zr, Cr, Ba, NajO, K»O, Ti, CaO, Y

Ni, Pb, Yb, B, Zn, S, C m i n , Cu, CaO, MgO, Sc, FeiOa,

V, La, Ba, Ga, Zr, Y. NajO, Sr, AIjOj, KjO, Cr

Yb, MgO, Cm ID, FeaOs, B, Zr, Ba, La, CaO, Y, V, NaiO,

Ga, Sc, Sr, KjO, AhO3 , Ti

C OIt, Cmin, Ag, Co, S, Ni, Pb, CaO, Cu, Tl. Zn, Sc, V,

MgO, Y, La, FeaO3 , Zr, Cr, Ga, Ba, NajO, Sr, Ti, AliOt

Co, Tl, Ag, S, Pb, Yb, Ni, V, Mn, Cmin , CaO, Zn, Cu,

FeaOa, Cr, La, Ga, AljO3, MgO, Y, Sr, K]O, Ti, Ba, Zr

Yb, S, Ag, Pb, Co, Cr, CaO, TI, NI, Mn, Cmin, Zn, Cu,

Ga, AljO3 , FeaO3, KjO, Ti, Sr, Y, La, MgO, NajO, Ba

Mn, Yb, Zn, Cu, Sc, Fe^j, CaO, Cm in , V, La, MgO, Y,

Zr, Ba, Sr, Ti, Cr, NaaO, KjO, AljOj

S, Co, Ag, Ni, Corf, Cu. B, Tl, MgO, Zn, Sc, Y, V, Fe,Oi,

La, Sr, Zr, Ba, Cr, NaaO, Ga, Ti, KjO

CHEROKEE GROUP FROM KANSAS AND OKLAHOMA

Major elements. More than 10 percent silicon was reported in all 

the samples from the Cherokee Group (set 11). Aluminum, which 

has a median concentration of 7 percent, is next in abundance, followed by total carbon, which has a median of 3.6 percent. Most of this 

carbon is organic. Some of the samples are slightly phosphatic, but 

phosphorus, in amounts of 2 percent or less, was detected in only 14 

samples, and its median value could not be determined. The other 

major elements, in approximate order of abundance, are potassium, 

iron, sodium, magnesium, calcium, and titanium.

Minor elements. The abundance of minor elements in these black 

shale samples is similar to that in other black shale samples associated 

with coal beds in the Interior coal province (for example, Vine, 1969, 

set 5). In genera], the samples from the Cherokee Group are characterized by high content of silver, chromium, gallium, lead, vanadium, 

and zinc at the 95th percentile. The median content of chromium and 

molybdenum is lower in set 11 than in set 5 and the median content of 

cobalt and gallium is higher. The content of strontium, lead, and zinc is 

higher in both sets 5 and 11 at the 95th percentile than in similar 

shales from the western Kentucky coal field (Vine, 1966, sets 1 and 2).

Element associations. Correlations for the elements in set 11 

(tables 7, 8) can be divided into three major groups, as shown in
H26 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 7. Coefficients of correlation for element pairs in set 11,

Al Fe Mg Ca Na K Ti Mn B Ba Be Co Cr Cu Oa La

Al 0.40

Fe

0.01 

-.21

Mg

-0.28

-.42

.63

Ca

0.29 

.31

-.07

-31

Na

0.44 

.47

-.11

-.34 

.45

0.45

.58

-.32

-.68 

.30 

.45

Ti

0.16 

.44

-.29

-.32 

.38 

.23 

.47

Mn

0.06 

.04

-.13

-.12 

.45 

,25 

.02 

.06

B

0.42 

.52

-.33

-.45 

.32 

.42 

.51 

.33

-.06

Ba

Significance level, 45 degrees of freedom

05 percent

0.29

99 percent

0.37

99.9 percent

0.47

1 Ct, total carbon.

2 Corg, organic carbon.

3 Cm in, carbonate carbon.

0.13 

.08 

.15 

.16 

.03 

.23 

.21

-.01 

.21

-.10

Be

-0.02 

.09

-.29

-.10 

.20 

.18 

.30 

.45 

.22 

.24

Co

-0.24

-.48 

.56 

.86

-.46

-.39

-.63

-.49

-.15

-..«0 

.11

-.23

Cr

-0.34

-.56 

.43 

.72

-.38

-.55

-.63

-.39 

.05

-.56 

.03

-.07 

.70 

Cu

0.29 

.53

-.57

-.69 

.29 

.36 

.40 

.34 

.17 

.49

-.12

-.04,

-.67

-.64

Ga

0.27 

.33 

.12 

.22 

.09 

.27 

.26 

.OS

-.01 

.36 

.25 

.14 

.28 

.01

-.06

La
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H27

47 core samples of the Cherokee Group from Kansas and Oklahoma

Mo

-0.27

-.52

.51

.85

-.45

-.47

-.70

-.51

-.17

-.44

.04

-.16

.88

. .76

- -. 67

.18

Mo

Ni

-0.26

-.39

.45

.74

-.49

-.38

-.66

-.45

-.25

-.43

.03

-.39

.75

.59

-.46

.11

.74

Ni

Pb

-0.08

-.11

.48

.73

-.31

-.13

-.41

-.09

-.16

-.22

.09

-.16

.70

.44

-.41

.37

.61

.48

Pb

Sc

0.30

.48

-.22

-.46

.38

.48

.52

.37

.24

.44

.06

.04

-.54

-.64

.55

.18

-.54

-.39

-.24

Sc

Sr

-0.19

-.29

.48

.82

-.20

-.18

-.47

-.19

-.22

-.19

.14

.06

.67

.53

-.55

.29

.65

.57

.67

-.34

Sr

V

-0.18

-.40

.65

.71

-.36

-.40

-.60

-.55

-.20

-.36

.02

-.39

.85

.57

-.55

.20

.83

.69

.53

-.44

.54

V

Y

-0.19

-.08

.14

.61

-.25

-.09

-.22

.07

-.19

-.02

.14

.20

.50

.30

-.36

.49

.42

,43

.50

-.19

.52

.27

Y

Zr

0.14

.29

-.32.

-.54

.35

.20

.69

.39

-.01

.30

-.07

.40

-.53

-.35

.05

.02

-.50

-.58

-.51

.12

-.36

-.48

-.24

Zr

Ag

-0.23

-.31

.39

.55

-.40

-.37

-.59

-.47

-.06

-.27

.03

-.22

.58

.56

-.31

.11

.62

.58

.34

-.46

.30

.52

.30

-.62

Ag

Zn

-0.30

-.47

.55

.83

-.40

-.44

-.63

-.43

-.30

-.37

.05

-.10

.83

. .67

-.70

.15

.87

.61

.62

-.58

.66

.73

.50

-.44

.58

ZiV

C,'

-0.24

-.51

.47

.87

-.35

-.42

-.73

-.32

-.05

-.54

.12

-.15

.81

.74

-.61

.12

.86

.69

.69

-.55

.64

.66

.45

-.55

.58

.82

c,

Coris

-0.22

-.50

.47

.86

-.36

-.41

-.74

-.37

-.05

-.53

.12

-.19

.82

.74

-.59

.12

.87

.69'

.69

-.56

.63

.68

.43

-.58

.62

.83

.99

O.r.

Cm in*

-0.20

-.26

.35

.60

-.10

-.21

-.29

.23

-.14

-.27

.20

.20

.40

.33

-.49

.09

.35

.34

.36

-.20

.52

:2i

.47

-.14

.02

.44

.51

.42
H28 CONTRIBUTIONS TO GEOCHEMISTRY

figure 4: (1) the detrital group, which shows a strong negative 

correlation with the organic carbon and mineral carbon groups and 

which consists of aluminum, zirconium, potassium, scandium, manganese, iron, titanium, barium, and gallium; (2) the organic-carbon 

group, which consists of nickel, silver, vanadium, molybdenum, copper, chromium, and zinc; and (3) the mineral carbon group, which consists of calcium, magnesium, strontium, and lead. Lanthanum and 

yttrium seem to fall between the major groups, whereas boron shows 

no particular correlation with any other element but possibly sodium. 

The proximity of the mineral carbon and organic carbon groups 

shown in figure 4 is probably due to the dilution effect of the dominant 

detrital group.

FIGURE 4. Rotated two-dimensional vector diagram of the principal-component 

analysis of the correlation matrix for set 11, 47 core samples of the Cherokee 

Group from Kansas and Oklahoma. Patterned areas suggest geochemical 

groupings of elements.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H2&

TABLE 8. Element associations in set 11, 1ft core samples of the Cherokee Group 

from Kansas and Oklahoma

[Elements are listed in order of increasing correlation coefficients. Eegular type used where the level of 

significance exceeds 95 percent; bold face type-used where the level of significance exceeds 99 percent]

Negative correlations- Element -^Positive correlation

Ti, Ga, Zr, Sc, Ba, Fe, K, Mn, Na

Ti, Ga, Sc, Fe, Mn, Zr, K, Na, Ba

Ti, Ga, Mn, Zr, Sc, K, Fe, Co, Ba, Na

Ti, Zr, Na, Ga, Mn, Ba, Fe, Co, Sc, K

Ga, Sc. Ti, Fe, Baf K, Mn, Na, Zr, Al

Zr, Ti, Mn, Sc, Na, K, Ga, Fe

Zr, Ti, Ga, Na

Ga, Ba, Ti, Zr, Co, Mn

Ti, Ga, Sc, Zr, Ba, Mn, Fe, Na, K

Ti, Ga, Sc, Fe, K, Zr, Mn, Na, Ba, B, Al

Ti, Ga, Zr, Sc, Ba, Fe, K, Mn, Na

. . Ga, Ti, Zr, Sc, Fe

Ga 

Ga, Ti

Zn 

Ni, Or, Mo, Zn, Ag, Cu, V, C0 rg, Ca,

Pb

Cu, Mo, Zri, CorB, V, Cr, Ni, Ag, Ca

Cu, Zn, Con, Mo, Cr, Ag, Ca, V, Ni, Sr

V, Mo, Cr, Ag, Ni, Zn, Cu, C0rg, Ca, Mg

V, Ni, Mg

Ag; Ni, COI g,"Gas Cr, Mo, Pb> V, Zn, Sr,

Cu, Mg 

Con, Mo, Ca, Ni, Cr, Cu, Zn, V, Ag, Sr,

' Pb, Mg, Gmin

Cu, Mo, Con, Cr, Zn, Ca, V, Ni, Ag, Sr 

Cu.Zn

Cu, Corg, Cr, Ca, Mo, Ni, Zn, V, Mg 

Zn, Ca, Mo, Cr, Cu, Corg, Mg, V, Sr,

' Cmm, Ni, Pb,Y, Ag.

Corg

Mo

V

Ni

Cu

Ag

Pb

La 

Mg 

Cr 

Zn 

Ca

Y

Cmin

Be 

B

Na .

K 

Sc 

.Mn Co' 

Zr 

Ti '' '

A 

.Ba 

Ga

Cmin. Y, Mg, Ag, Sr, V, Pb, Ni, Cu, Cr, Zn, Ca, Mo> 

Cmin, Y, Mg, Pb, Ag, Sr, Ni, Cu, V, Ca, Corg, Zn, Cr 

Ag, Pb, Sr, Cu, Mg, Corg, Ni, Ca, Zn, Mo, Cr 

Cmin, Y, Mg, Pb Sr, Ag, Cu, Zn, V, Corg, Mo, Ca, Cr 

Cmin, Y, Mg, Pb, Sr, Ag, V, Ni, Zn, Cr, Ca, Corg, Mo. 

Sr, Y, Pb, Mg, V, Ca, Cu, Ni, Zn, Cr, Corg, Mo 

Ag, Cmin, La, Cu, Mg, Ni, Y, V, Mo, Zn, Sr, C0rg,

Cr, Ca

Sr, Fe, Ba, Pb, Y

Cmin, Ag, Cu, Ni, Corg, Sr, Pb, Mo, Zn, Cr, Ca, V 

Cmin, Y, Mg, Ag, Sr, Pb, Cu, Ni. Corg, Zn, V, Ca, MoCmin, Y, Mg, Ag, Ni, Pb, Sr, Cu, V, Cr, Corg, Ca, Mo 

Ag, Cmin, Y, Mg, V, Cu, Pb, Ni, Sr, Zn, Mo, Cr, Corg 

La, Ag, Mg, Y, Cmin, Cu, V, Ni, Corg, Mo, Zn, Pb,

Cr, Ca

Cu, Ag, Mo, Corg, Ni, Cmm, La, Pb, Zn, Cr, Sr, Ca 

Cu, Ni, Mg, Mo, Pb, Cr, C0rg , Zn, Y, Sr, Ca

Na

Ga, Al, Ti, Fe, Ba, Zr, Sc, Mn, B, K

Ga, Ba, Al, Na, Fe, Sc, Ti 

Al, Na, Mn, Ba, K, Fe, Ti, Ga 

Ba, Ga, Sc, Na, Zr, Co, Fe, Ti 

Ti, Zr, Mn 

Ba, Fe, Na, Mn, Co, Ti

Na, Co, Ga, Al, Mn, K, Ba, Sc, Fe, Zr

Zr, Na,: La, AI, Mn, K, Sc, Ba, Ga, Ti

Ga, Na, Sc, Fe, Ba, K, Ti

Zr, Na, Mn, La, K, Al, Sc, Ga, Ti, Fe

Al, Na, Mn,,K, Ti, Ba, Fe, Sc

It is of particular interest to compare this set with set 5, described 

in another report (Vine,-1969}, in view of their similar stratigraphic 

setting. The samples in set 5 were collected from outcrops and shallow 

artificial exposures in the same strata represented by core samples in 

set 11. In both sets the organic carbon fraction includes nickel, vanadium, molybdenum, silver, chromium, and copper, and the detrital 

fraction includes titanium, zirconium, gallium, and scandium. The 

chief differences are among elements that may be mobile in the zone of 

weathering. These are sodium, potassium, iron, and manganese.
H30 CONTRIBUTIONS TO GEOCHEMISTRY

UPPER PALEOZOIC BLACK SHALE FROM ARKANSAS 

AND OKLAHOMA

Major elements. In set 12 the major elements, in decreasing order 

of abundance, are silicon, aluminum, iron,-potassium, sodium, carbon, 

magnesium, titanium, and calcium. Silicon content exceeded 10 percent 

in each of the 30 samples, and aluminum exceeded 10 percent in 26 of 

the samples. The median value for total carbon is only 0.91 percent, 

and at the 95t'h percentile total carbon content is only 2.7 percent. Most 

of this carbon is organic; only a minor part is mineral.

Minor elements. The gross minor-element content of the samples 

in set 12 is similar to that in set 9. This distribution may be typical 

of fine-grained marine sedimentary rocks that contain only a small 

amount of organic material. Barium, gallium, and zirconium contents 

are relatively high at the 95th percentile. Gallium and zirconium are 

most likely to be contained in minerals of detrital origin, whereas 

barium is probably in minerals of authigenic or diagenetic origin, and 

its distribution is probably related to the barite deposits at the base of 

the Stanley Shale.

Element associations. The correlations among element groups computed for set 12 (tables 9,10) show tliat most of the elements fall in 

the detrital-mineral group, as shown on the vector diagram (fig. 5). 

These elements are iron, potassium, gallium, lead, manganese, cobalt, 

magnesium, scandium, sodium, titanium, zirconium, ytterbium, niobium, and possibly lanthanum. Nickel and chromium seem to form a 

separate group, but they are probably of detrital origin also. Organic 

carbon has a negative correlation with the principal detrital elements. 

Vanadium has no significant positive correlations, but it seems to be 

more closely associated with organic carbon than with any other element. Copper, barium, and boron all seem to be independent of other 

elements although copper and barium show a positive correlation with 

each other. Mineral carbon and calcium fall in the same segment of 

the vector diagram as strontium, yttrium, and beryllium; but the 

correlations are poor, and* therefore they may not all be associated 

geochemically.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H31

FIGURE 5. Rotated two-dimensional vector diagram of the principal-component 

.analysis of the correlation matrix for set 12, SO samples of upper Paleozoic 

.black shale from Arkansas and Oklahoma. Patterned areas suggest geochemical 

groupings .of elements.
CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 9. Coefficients of correlation for element pairs in set IS, SO

Fe

Fe

Mg

0.74

Mg

Ca

0.30 

.36

Ca

Na

0.81 

.71 

.43

Na

K

0.86 

.64 

.19 

.79

K

Ti

0.69 

.69 

.35 

.82 

.68

Ti

Mn

0.79 

.66 

.37 

.57 

.62 

.49 

Mn

B

-0.08 

-.07 

-.31 

-.11 

.05 

.10 

-.08

B

Ba

0.02 

-.21 

-.47 

-.05 

.26 

-.03 

-.06 

.08

Ba

Be

0.28 

.25 

.14 

.46 

.37 

.36 

.08 

-.49 

.13

Be

Co

0.78 

.68 

.40 

.68 

.62 

.56 

.58 

-.35 

-.23 

.33

Co

Cr

0.41 

.32 

.00 

.59 

.54 

.64 

.24 

.49 

.05 

.03 

.30

Cr

Cu

-0.46 

-.47 

-.39 

-.55 

-.35 

-.45 

-.47 

-.02 

.37 

-.21 

-.29 

-.31

Cu

Qa

0.83 

.68 

.20 

.85 

.85 

.75 

.59 

.11 

.00 

.35 

.63 

.70 

. -.35

Qa

Significance level, 28 degrees of freedom

95 percent

0.36

99 percent

0.46

99.9 percent

0.57

i Ct, total carbon. 

a Corg, organic carbon. 

* Cmm, carbonate carbon.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H33

samples of upper Paleozoic black shale from Arkansas and Oklahoma

La

0.40

.69

.07

.66

.57

.69

.22

-.26

.05

.60

.50

.31

-.12

.58

La

Nb

0.67

.59

.23

.71

.74

.69

.51

-.14

.19

.51

.55

.32

-.48

.54

.59

Nb

Ni

0.72

.46

.23

.51

.67

.56

.63

.11

-.07

.11

.71

.47

-.20

.64

.33

.44

Ni

Pb

0.57

.40

.02

.48

.64

.38

.29

-.12

.09

.23

.69

.35

-.04

.58

.58

.37

.59

Pb

Sc

0.82

.65

.23

.79

.85

.70

.54

.09

.00

.29

.57

.52

-.42

.81

.57

.64

.59

.51

Sc

Sr

-0.08

-.12

.67

.21

.08

.12

-.06

-.50

.02

.50

.12

-.05

. -.08

.03

.10

.21

-.02

-.04

-.02

6r

V

-0.44

-.08

.06

-.21

-.27

.02

-.59

.11

-.17

.00

-.20

.02

.13

-.26

.11

-.07

-.24

-.07

-.32

.21

V

Y

0.06

.02

.16

.16

.07

.10

-.05

-.60

-.02

.64

.09

-.27

-.19

.00

.40

.32

-.16

-.07

.19

.52

.01

Y

Yb

0.66

.56

.25

.69

.76

.72

.45

.09

.29

.14

.57

.58

-.21

.61

.50

.76

.55

.51

.62

.12

.03

-.05

Yb

Zr

0.60

.55

-.04

.62

.56

.69

.44

.22

.03

.07

.36

.47

-.36

.54

.45

.64

.39

.29

.70

-.32

-.24

-.02

.61

Zr

Ct»

-0.61

-.54

.00

-.38

-.54

-.38

-.48

.18

-.32

-.15

-.52

.04

-.05

-.33

-.44

-.60

-.46

-.43

-.49

.17

.30

-.08

-.61

-.52

Ct

<w

-0.67

-.60

-.10

-.40

-.57

-.40

-.58

.14

-.25

-.09

-.57

-.02

.00

-.38

-.42

-.57

-.53

-.47

-.54

.21

.35

.02

-.62

-.51

.97

Cor,

Cmin3

0.01

.-09

.29

-.02

-.02

-.03

.16

.25

-.33

-.22

-.11

.31

-.28

.09

-.20

-.24

.14

-.14

.00

-.01

-.03

-.27

-.12

-.15.

.66

.40

Cmln
H34 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 10. Element associations in set 12, 30 samples of upper Paleozoic black 

shale from Arkansas and Oklahoma

[Elements are listed in order of increasing correlation coefficients. Regular type used where the level of 

significance exceeds 95 percent; boldface type used where the level of significance exceeds 99 percent]

Negative Correlation<-

Con

B

B

B

Ba, Cu

Y, Sr, Be

Cu, Con

CU, Con

Corn Cu

Con

Corg, Cu

Corg, Cu

Con

Con. Cu

Cor,

Con

V, Con, Cu

Corl

Corl

Con, CU, V

Fe, Yb, Mg, Mn, Nb, K, Co, Sc,

Ni, Zr, Pb, La, Ti, Na, Ga

Mn,Fe

Ca

Na, Nb, Mn, Mg, Fe, Ti, Sc,

Ca, Zr

Element

La

Be

Y

Sr

Ca

Cmin

B

Cr

Ti

Na

Nb

Yb

Zr

Sc

Oa

Mg

Co

Ni

Mn

Pb

K

Fe

Cor.

V

Ba

Cu

-^Positive Correlation

Y, Zr, Fe, Yb, Co, Na, K, Sc, Pb, Ga, Nb, Ti, Mg, Be

Ti, K, Na, Sr, Nb, La, Y

La, Sr, Be

Be, Y, Ca

Mg, Mn, Co, Na, Sr

Cor. :

Cr

Fe, Zr, Ni, B, Sc, K, Yb. Na, TI, Ga

Be, Pb, Mn, Ni, Co, La, Cr, K, Zr, Nb, Mg, Fe, Sc, Yb,

Ga, Na

Ca, Be, Pb, Ni, La, Mn, Cr, Zr, Co, Yb, Nb, Mg. Sc, K,

Fe, Ti, Ga

Pb, Ni, Be, Mn, Ga, Co, La, Mg, Sc, Zr, Fe, Ti, Na, K, Yb

Mn, La, Pb, Ni, Mg, Co, Cr, Zr, Ga, Sc, Fe, Na, Ti, K, Nb

Co, Ni, La, Mn, Cr, Ga, Mg, K, Fe, Yb, Na, Nb, Ti, Sc

Pb, Cr, Mn, Co, La, Ni, Yb, Nb, Mg, Zr, Ti, Na, Ga, Fe, K

Zr, Nb, La, Pb, Mn, Yb, Co, Ni, Mg, Cr, Ti, Sc, Fe, Na, K

Ca, Pb, Ni, Zr, Yb, Nb. La, K, Sc, Mn, Ga, Co, Ti, Na, Fe

Zr, Ca, La, Nb, Ti, Yb, Sc, Mn, Pb, K, Ga, Na, Mg, Ni, Fe

Zr, Nb, Mg, Cr, Na, Yb, Ti, Sc, Pb, Mn, Ga, K. Co. Fe

Ca, Yb, Zr, Ti, Nb, Sc, Na, Co. Ga, K, Ni, Mg. Fe

Nb, Ti, Mg, Na, Sc, Yb, Fe, Ga, La, Ni. Co, K

Be, Cr, Zr, La. Co, Mn, Pb, Mg, Ni, Ti, Nb, Yb, Na, Sc,

Ga, Fe

Cr, La, Pb, Zr, Yb, Nb, Ti, Ni, Mg, Co, Mn, Na, Sc, Ga, K

Cm,n

Cu

Ba

SUMMARY AND CONCLUSIONS

Black shale is the name given to a wide variety of dark-colored finegrained marine sedimentary rocks composed of a mixture of detrital 

minerals, chemically or biologically precipitated minerals, and organic 

matter. Each of the three major components of these rocks may contain a characteristic suite of major and minor elements. Rocks from 

different environments may be characterized by different suites of 

elements that are assignable to each of the major rock-forming components. In this study, coefficients of correlation were used to suggest 

the suite of elements associated with the major rock-forming components in four different sets of samples. Marked differences were 

found in the four sets of samples studied, each set representing a
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H35

different environment of black shale deposition. Most of the sample 

sets included other rock types associated with black shale and 

transitional with black shale.

Samples of the Belden Shale and associated rocks from a deep 

trough of Pennsylvanian rocks in central Colorado were found to be 

chiefly detrital in origin. These rocks are dark gray but do not contain 

much organic matter. Only lead and copper show any tendency to be 

associated with the organic matter. Chemically or biologically precipitated minerals are also a minor constituent of these rocks, and only 

calcium, magnesium, and manganese are associated with the carbonate 

fraction of the rocks. The only unusual concentrations of minor elements are associated with the inorganic mineral component of the 

Belden Shale samples. High boron, beryllium, gallium, and possibly 

lithium are associated with the authigenic and detrital mineral fractions and may reflect a similar concentration of the same elements 

along with lead in the source area terrane in Precambrian rocks of the 

ancestral Kocky Mountains. Deposition and burial in this trough 

probably proceeded so rapidly that there was little opportunity for 

the chemically or biologically precipitated minerals to accumulate or 

for the thinly disseminated organic matter to adsorb minor elements 

from the sea water.

The samples of upper Paleozoic black shale and associated rocks 

from the Ouachita geosyncline in Arkansas and Oklahoma are similar 

in many respects to the Belden Shale samples from Colorado. Like 

the Belden Shale, these rocks are chiefly detrital, and, although they 

contain sufficient organic matter to impart a dark-gray color, they 

show little association between any of the minor elements and the 

organic matter or the sparse carbonate minerals present. Most of the 

major and minor elements occur in the detrital-mineral fraction. 

Barium, gallium, and zirconium are present locally in relatively high 

concentration. Gallium and zirconium are associated with the detritalmineral fraction and are probably of detrital origin. Barium, which 

probably occurs as the authigenic mineral barite, is not associated 

with anything else that was determined in the rocks, except possibly 

copper. Minable deposits of barite occur locally at the base of the 

Stanley Shale. The apparent localization of the barite along the axes 

of folds indicates secondary redistribution after deposition of the 

enclosing rocks. A similarly high concentration of barium was found 

in the western-fades eugeosynclinal rocks of Nevada (Vine, 1966)..

The distribution of elements in samples of the Cherokee Group 

from Kansas and Oklahoma is significantly different from that of the 

other sample sets discussed here. Because of the similarity with other
H36 CONTRIBUTIONS TO GEOCHEMISTRY

sets of samples from the Pennsylvanian strata in the Interior coal 

province, these samples from the Cherokee Group may be considered 

.a good example of shallow-water transgressive marine sediments 

deposited on the continental platform. Elements showing local enrichment in these rocks include silver, zinc, chromium, and vanadium in 

.association with organic matter, lead in association with carbonate 

mineral matter, and gallium and zirconium in association with the 

detrital-mineral fraction. Samples from the Kansas and Oklahoma 

area have more lead and zinc and less molybdenum than similar rocks 

in western Kentucky. Some of the elements associated with organic 

matter were probably extracted from sea water by adsorption or by

 complexing with the decaying organic matter at the time of deposition. 

To what extent minor elements were added later to the rock by adsorption from connate waters after deposition and burial cannot be evaluated from the present data. 

Samples of black shale and associated rocks, including cherty and

 dolomitic siltstone from the Houy Formation in Texas, are the most 

interesting and unusual of the rocks included in this study. Four rock

 constituents in addition to silica can be distinguished: a carbonatemineral fraction, organic matter, a sulfide-mineral fraction, and a 

detrital-mineral fraction. Many minor elements including cobalt, copper, molybdenum, nickel, lead, thallium, zinc, and vanadium are unusually abundant. Except for vanadium, all are associated with

 organic-matter and the sulfide-mineral fractions of the rock. Other 

investigators have suggested that these rocks were probably deposited 

very slowly from quiet shallow marine waters on the continental platform. The black shale facies is only about 12 feet thick and may represent a restricted lagoonal setting contemporaneous with the more 

widely distributed black shales of the Chattanooga Shale equivalents 

in the midcontinent area. A slow rate of deposition may be one important factor in the concentration of minor elements with organic 

matter and sulfide minerals. The elements now concentrated in the 

black shale may have been adsorbed by decaying organic matter from 

the sea water at the time of deposition. If so, the sea water could not 

have been greatly enriched in these elements, for many are highly toxic 

and could not have coexisted with the abundance of organisms required to produce the amount of organic matter in the rocks. One 

other alternative that cannot be proved with the present data is that 

the organic matter could also have adsorbed the minor elements from 

connate water after deposition and burial of the sediment.
ELEMENT DISTRIBUTION IN SOME TYPES OF BLACK SHALE H37

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H38 CONTRIBUTIONS TO GEOCHEMISTRY

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o