Element Distribution 

in Some Paleozoic 

Black Shales and 

Associated Rocks

By JAMES D. VINE

CONTRIBUTIONS TO GEOCHEMISTRY

GEOLOGICAL SURVEY BULLETIN 1214-G

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. HIGKEL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

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

Washington, D.C. 20402 - Price 25 cents (paper cover)
CONTENTS

Page

Abstract. _________________________________________________________ Gl

Introduction. _____________________________________________________ 1

Acknowledgments. ________________________________________________ 2

Sample sets._.____________________________________________________ 3

Chemical methods of analysis.______________________________________ 9

Statistical methods._______________________________________________ 9

Distribution and association of elements__._____.__-__________________ 11

Pennsylvanian black shales from Kansas and Oklahoma.___________ 12

Permian Meade Peak Phosphatic Shale Member of the Phosphoria

Formation._________________________________________________ 17

Upper Devonian Chattanooga Shale_____________________________ 19

Pennsylvanian Paradox Member of the Hermosa Formation._______ 23

Summary and conclusions.___-__-___-_-_-_-_---________-_-_-_______ 26

References cited..._________________________________________________ 31

ILLUSTRATIONS

Page

FIGURE 1. Sample localities of black-shale sample sets 5-8- _----__--___ G4 

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

principal-component analysis of the correlation 

matrix for:

2. Set 5, 40 samples of Pennsylvanian black shales from

Kansas and Oklahoma.________________________ 15

3. Set 6, 43 samples from the Meade Peak Phosphatic

Shale Member of the Phosphoria Formation.______ 19

4. Set 7, 51 samples of Chattanooga Shale.____________ 23

5. Set 8, 25 samples of black shale from the Paradox

Member of the Hermosa Formation. __.__-_--_-_. 27

TABLES

Page 

TABLE 1. Stratigraphic sequence of black-shale units from which

samples in set 5 were collected.________________________ G5

2. Substitutions made in data sets 5-8_____________________ 10

in
IV CONTENTS

Page 

TABLE 3. Element content in four sets of Paleozoic black-shale samples. G12

4. Correlation coefficients for element pairs in set 5, 40 samples

of Pennsylvanian black shales from Kansas and Oklahoma. 16

5. Element associations in set 5, 40 samples of Pennsylvanian

black shales from Kansas and Oklahoma. _______________ 17

6. Correlation coefficients for element pairs in set 6, 43 samples 

of black shale, dolomite, and phosphorite from the Meade 

Peak Phosphatic Shale Member of the Phosphoria 

Formation. ________________________________________ 20

7. Element associations in set 6, 43 samples of black shale, 

dolomite, and phosphorite from the Meade Peak Phosphatic Shale Member of the Phosphoria Formation__ _ _ _ 22

8. Correlation coefficients for element pairs in set 7, 51 samples

of Chattanooga Shale_._____.________--_--_---___-__ 24

9. Element associations in set 7, 51 samples of Chattanooga

Shale......._.._._._..___.____.._...___ _._ .._.__ 26

10. Correlation coefficients for element pairs in set 8, 25 samples 

of black shale from the Paradox Member of the Hermosa 

Formation._________________________________________ 28

11. Element associations in set 8, 25 samples of black shale from

the Paradox Member of the Hermosa Formation_ _______ 30
CONTRIBUTIONS TO GEOCHEMISTRY

ELEMENT DISTRIBUTION IN SOME PALEOZOIC BLACK 

SHALES AND ASSOCIATED ROCKS

By JAMES D. VINE

ABSTRACT

The content of chemical elements in four sets of Paleozoic black-shale samples 

was determined, and the data were analyzed statistically in search of element 

associations that may have geochemical significance. Silicon, aluminum, titanium, 

zirconium, and gallium generally are the principal elements in the detrital mineral 

fraction of these rocks. Locally, boron, beryllium, scandium, and vanadium are 

also in the detrital fraction. Calcium, magnesium, and manganese are associated 

chiefly with the carbonate-mineral fraction, where present. Different groups of 

elements are associated with the organic-matter fraction of these rocks in the 

different sets of samples. In the hypersaline carbonate-rich detrital rocks of the 

Pennsylvanian Paradox Member of the Hermosa Formation of Utah, copper 

and zinc are asso " Uc?d with the organic matter, but neither element is highly 

concentrated in the rocks. The geoehemical behavior of the minor elements in 

this evaporite basin is not known. Iron, cobalt, nickel, molybdenum, and uranium are associated with organic matter in the Devonian Chattanooga Shale 

of central Tennessee and northern Alabama, :md uranium and cobalt tend to 

be enriched in this epicontinental shallow-sea deposit. Copper, nickel, vanadium, 

chromium, molybdenum, lead, and calcium are associated with organic matter 

in the Pennsylvanian black shales of southeastern Kansas and northeastern 

Oklahoma. Of these, vanadium, chromium, nickel, and lead seem to have been 

locally enriched in this brackish or marine shallow-water shelf environment. In 

the silts-tones and phosphatic shales of the Permian Meade Peak Phosphatic Shale 

Member of the Phosphoria Formation, selenium, copper, molybdenum, chromium, 

nickel, and scandium are associated with organic matter in the detrital rocks; 

silver is more closely associated with the detrital mineral fraction; vanadium, 

zinc and lanthanum are associated with the organic matter in the more phosphatic shales; and yttrium is associated with phosphorite. All these elements 

except scandium are concentrated to an abnormally high degree in the Meade 

Peak Phosphatic Shale Member. The upwelling cold water that provided nutrients for an abundance of living organisms and that gave rise to the accumulation of phosphate along the margin of the Cordilleran miogeosyncline was 

probably also the source of the minor elements.

INTRODUCTION

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

geoehemical distribution of elements in black-shale deposits of differGl
G2 CONTRIBUTIONS TO GEOCHEMISTRY

ent environments and of different ages. The first report (Vine, 1966a) 

compared the element distribution in some shelf and eugeosynclinal 

black-shale samples grouped into four sets, numbered 1^4. The present 

report continues with the summary of chemical data pertaining to four 

more sample sets, numbered 5-8. The latter four sets represent four 

diverse environments of black-shale deposition; they are different mineralogically and were collected by different techniques. The samples 

were analyzed by a routine six-step spectrographic method for major 

and minor elements, and chemically for organic carbon and mineral 

carbon. The range in content of each of the elements determined is 

described, and the relations of the elements to different major constituents of the rocks are discussed.

Many fine-grained marine rocks are composed of various proportions of detrital minerals, chemically or biologically precipitated 

minerals, and organic matter. Refined laboratory techniques would be 

required to determine the proportions of each mineral species and to 

provide a means of interpreting the source of each. Therefore, the 

term "black shale" is used in a broad sense to include many dark-colored rocks that are not obviously classifiable as claystone, siltstone, 

limestone, dolomite, anhydrite, chert, phosphorite, or coal. These specific rock types commonly grade into black shale, and in some of 

the sets of samples, one or more end-member rock types are included. 

Where more than one end-member rock type was among the samples 

of black shale, the elements showed a much wider range in concentration. Furthermore, by including a few samples of the end-member 

rock types, the distribution of the minor elements with respect to the 

detrital mineral fraction, the chemically or biologically precipitated 

mineral fraction, and the organic-matter fraction can be more clearly 

defined.

ACKNOWLEDGMENTS

For their suggestions and encouragement in collecting the samples 

from southeastern Kansas, I thank F. C. Foley, State Geologist of 

Kansas, and various members of his staff. J. D. Love of the U.S. Geological Survey provided the necessary information to aid in collection 

of the Phosphoria Formation samples. J. I. Reese assisted in collecting 

these samples. The late Andrew Brown of the U.S. Geological Survey, 

at the time of his death in 1964, had an unpublished manuscript listing 

the locality and sample descriptions of the Chattanooga Shale cores. 

His locality and sample descriptions are included in the present report. 

0. B. Raup and R. J. Hite of the U.S. Geological Survey, as part of 

their studies of potash and other mineral commodities in the Paradox 

Basin, Utah, helped to obtain samples of the Paradox Member. E. B. 

Tourtelot and J. R. Keith assisted in the compilation of data.
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G3

Spectrographic analyses upon which this report is based were made 

by A. L. Sutton, Jr., and J. C. Hamilton, and most of the carbon 

analyses were made by I. C. Frost, all of the Denver laboratory of the 

U.S. Geological Survey. Other analyses were made in the Denver laboratory by E. J. Fennelly, G. T. Burrow, D. L. Skinner, Harriet Neiman, Wayne Mount joy, J. D. Mensik, and Lorraine Lee. Uranium 

analyses of the Chattanooga Shale samples were made in the Washington laboratory of the U.S. Geological Survey by Carmen Hoy, Joseph 

Budinsky, B. A. McCall, J. H. Goode, J. Smith, and J. J. Warr.

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

analytical data to punch cards. Computer programing and assistance 

was provided by R. N. Eicher, F. B. Sower, and G. I. Seiner.

SAMPLE SETS

Locality descriptions, listings of the individual stratigraphic intervals sampled, and analyses of individual samples for sets 5-8 are included in an open-file report (Vine, 1966b) available for consultation 

or reproduction at the libraries of the principal offices of the U.S. 

Geological Survey. Sample localities of sets 5-8 are shown in figure 1. 

Generalized descriptions of each sample set are given below.

Set 5 consists of 40 samples collected from outcropping black-shale 

beds of Pennsylvanian age in southeastern Kansas and northeastern 

Oklahoma. At least 13 different shale beds are represented by the'40 

samples. The beds are dark gray to black, are fissile where even 

slightly weathered, and commonly contain fish scales, conodonts, and 

brachiopods. Phosphate nodules 1-2 cm (centimeters) across are especially characteristic of the Excello Formation of Searight and 

others (1953), but they also occur in many of the other beds. Typically, 

these black-shale beds are 1-3 feet thick, and they overlie a bed of 

coal and are overlain by marine limestone. Exceptions to this generalization are the Pleasanton Group, which is as much as 15 feet thick, 

and the Eudora Shale Member, which separates two limestone beds in 

the Stanton Limestone. The stratigraphic sequence of black-shale units 

and the number of samples collected from each unit are given in 

table 1.

Set 6 consists of samples from the entire sequence of black siltstone, 

phosphorite, dolomite, and limestone of the Meade Peak Phosphatic 

Shale Member of the Phosphoria Formation of Permian age. The 

member is exposed in a mine opening at Raymond Canyon in Sublette 

Ridge, Lincoln County, Wyo. The strata in this part of the western 

Wyoming fold belt are nearly vertical, strike approximately north, 

and dip to the east. The main adit extends along the strike of the beds. 

Open crosscuts perpendicular to the strike of the beds provide easy
G4 CONTRIBUTIONS TO GEOCHEMISTRY

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ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G5

TABLE 1. Stratigraphic sequence of black-shale units from which samples in set 6

were collected

[The intervening members or formations that were not sampled are not shown]

System

PENNSYLVANIAN

Series

MISSOURI

DBS MOINES

Group

O

35 i i

03

35 < 

A

CQ

tyfc£ s°

oblZ

<0 

W£n 

Jfc *3

MARMATON

OF (1956) CHEROKEE HOW 

CABANISS SUBGROUP (1956) OF HOWE 

SUBGROUP KREBS HOWE (1956) OF 

Formation

Stanton Limestone

lola Limestone

Pawnee Limestone

Fort Scott Limestone

Excello Formation of Searight 

and others (1953)

Verdigris Formation of Smith 

(1928)

Croweburg Formation of 

Abernathy (1937)

Scammon Formation of 

Abernathy (1937)

Tebo Formation of McQueen 

(1943)

Bluejacket Formation of Howe 

(1956)

Warner Formation of Howe 

(1956)

Member

Eudora Shale

Muncie Creek Shale

Mine Creek Shale

Anna Shale

Little Osage Shale of Jewett 

(1941)

Tiawah Limestone of Searight 

and others (1953)

Number 

of 

samples

2

2

3

1

2

3

14

3

1

3

3

1

2

access to almost the complete thickness of the Meade Peak Member. 

As samples were collected underground, they are unweathered and 

show no evidence of the fissility characteristic of many of the silty 

beds in outcrop. The samples were collected from individual beds 

0.4-8.5 feet thick and are intended to represent the various lithologies

329-581 O 69-
G6 CONTRIBUTIONS TO GEOCHEMISTRY

present. Rock types in the Meade Peak Member grade into each other 

in all proportions. Viewed in thin section, many samples were found 

to contain recognizable amounts of carbonaceous matter, silt grains, 

phosphate oolites, and carbonate minerals. Pure siltstone, dolomite, and 

phosphorite are less common than the mixed lithologies. Mineral identification by X-ray diffraction of a number of samples showed major 

amounts of quartz, dolomite, and carbonate-fluorapatite, as well as 

minor amounts of calcite, mica, and feldspar and very small amounts 

of clay minerals. The stratigraphic sequence, petrology, mineralogy, 

and chemistry of the Meade Peak Shale Member at nearby Coal Canyon were described by Gulbrandsen (1960).

Set 7 consists of samples representing the complete section of Chattanooga Shale of Late Devonian age as penetrated in five core holes 

in the interior low plateau of central Tennessee and northern Alabama. These five cores were selected on the basis of availability and 

geographic distribution from about 75 cores drilled by the U.S. Geological Survey and the U.S. Bureau of Mines on behalf of the U.S. 

Atomic Energy Commission. The "standard section" of the Chattanooga Shale, as exposed in a roadcut near Sligo Bridge, 7 miles east 

of Smithville, De Kalb County, Tenn., was described by Coriant and 

Swanson (1961 p. 24). There, the Chattanooga Shale consists of five 

major units: the Gassaway Member, at the top, comprises the three 

upper units, and the Dowelltown Member, at the base, comprises the 

two lower units. The upper and lower units of the Gassaway Member 

and the lower unit of the Dowelltown Member consist chiefly of black 

silty shale. The other two intervening units contain some gray as well 

as black laminae. The five cores were sampled, and the geologic units 

were identified by L. C. Conant, T. M. Kehn, Andrew Brown, and 

Lynn Glover, U.S. Geological Survey. In only one of the five cores, 

C-12, were all five units of the Dowelltown and Gassaway Members 

identified by the samplers. This core, 33.36 feet long, drilled near the 

standard section, was divided into 28 samples that range from 0.44 to 

2.58 feet in length. In two cores, only the Gassaway Member was recognized. In the other two cores, both members were recognized, but 

the individual units were not. The 23 samples from core holes C-53, 

C-47, C-60, and C-65 represent a total thickness of more than 69 feet, 

and the individual samples range from 0.80 to 5.36 feet in length.

Set 8 consists of 25 core samples of carbonate-rich black shale from 

the saline facies of the Paradox Member of the Hermosa Formation, 

of Pennsylvanian age, taken from a drill hole near the crest of the 

Cane Creek anticline about 7 miles southwest of Moab, Utah. The 

saline facies, as defined by Kite (1960, 1961), consists of a sequence 

of at least 29 evaporite cycles (numbered from the top down). Each
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G7

complete cycle includes beds of black shale, limestone, dolomite, anhydrite, and halite. Southwestward, the limestone and dolomite beds 

tend to thicken and merge at the expense of the anhydrite and halite; 

the halite is thickest in the central and northeastern parts of the basin. 

The 30 or more beds of black shale, 10-40 feet thick, commonly extend 

the entire width of the basin. Of the black-shale core samples, 12 were 

collected from the interval between salt beds 3 and 4; nine were collected from the interval between salt beds 4 and 5; and four were 

collected from the interval between salt beds 2 and 3. Individual 

samples averaged about 0.1 foot thick.

The major minerals of several black-shale samples, as shown by 

X-ray diffraction analysis, are quartz, calcite, dolomite, and mica. 

Minor amounts of anhydrite and halite are present in some samples. 

In thin section, carbonate and mica grains less than 0.05 mm (millimeters) across can be distinguished, but most of the quartz is too fine 

grained to be readily visible. The samples have a nearly homogeneous 

texture, with a faint indication of lamination resulting from horizontal lenses of pyrite, calcite, and carbonaceous matter. Some calcite 

lenses are flattened whole brachiopod shells whose interior cavities are 

filled with pyrite and sphalerite.

The four sets of samples are markedly different in lithology, environment of deposition, degree of weathering, and age. The Pennsylvanian shales from southeastern Kansas and northeastern Oklahoma 

(set 5) were probably deposited in a. transgressive shallow brackishwater or marine shelf north of the Ouachita geosyncline and adjacent 

to shore areas where coal swamps were forming. The presence of fish 

remains and phosphatic nodules suggests that life was abundant, but 

most of the organic matter in these rocks is too fine grained to be 

specifically identified. This organic matter probably consists of humic 

materials from the nearby coal swamps intermixed with marine plants 

and animals, all of which have been decomposed by the action of 

micro-organisms. These samples were collected from outcrops and, 

therefore, have been somewhat altered by weathering.

The Meade Peak samples (set 6) include phosphorite and dolomite, 

in addition to black siltstone; thus, they include a much wider range 

of lithologies than the other sample sets. In discussing the distribution 

of the carbonaceous rocks in the Phosphoria Formation, McKelvey 

and others (1959, p. 2,23-24) suggested that the organic muds accumulated under reducing conditions near the east margin of the Cordilleran 

miogeosyncline in a relatively shallow marine shelf a considerable distance from land. Furthermore, they suggested that the phosphate and 

other chemical sediments in the Phospboria- were derived from upwelling cold oceanic waters, following a mechanism proposed by
G8 CONTRIBUTIONS TO GEOCHEMISTRY

Kazakov (1937) to explain the origin of nutrients required to support 

a tremendous bloom of plankton and nekton. The organic matter is 

therefore probably chiefly of marine origin, including mainly plankton and fish, but for most of the organic matter the specific organisms 

cannot be identified.

The Chattanooga Shale samples (set 7) are from a unit deposited in 

quiet marine waters on an intracratonic platform which was part of a 

broad epicontinental sea that extended westward from a geosyncline. 

The unit is thickest in eastern West Virginia. At times this inland sea 

spread as far west as New Mexico and Montana. The marine origin 

of the black shale is generally accepted on the basis of the conodonts, 

lingulid brachiopods, and other fossils present, and quiet water is 

generally inferred, owing to the uniform, thinly laminated character 

of the rocks. Some geologists have preferred the explanation that 

deposition in deep water sustained the .stagnant environment necessary 

to preserve organic matter. Conant and Swanson (1961, p. 62) suggested, however, that the Chattanooga Shale was deposited in water 

only a few tens of feet deep, and this interpretation seems to be well 

documented. Plant material, including spores and sparse woody fragments, occurs throughout the Chattanooga (J. M. Schopf, written 

commun., 1953), but the proportions of terrestrial and marine organisms that have contributed to the carbonaceous matter are not easily 

determined. From a study of oil yield and uranium content of identifiable humic and sapropelic constituents in the Chattanooga Shale and 

its equivalents, Swanson (1960, p. 11, 12) estimated that each kind of 

organic matter comprises about half of the total organic matter in 

the rock. Breger and Brown (1963), however, concluded from a study 

of organic isolates that most of the organic matter in the Chattanooga 

Shale is related to coal and is of terrestrial origin. This latter conclusion is difficult to accept because of the widespread distribution of 

phosphate in the Chattanooga Shale, which suggests that a large area 

of shallow water supported abundant life.

The calcareous black-shale beds of the Paradox Member of the 

Hermosa Formation (set 8) were deposited in a deep hypersaline 

marine basin in Pennsylvanian time (Hite, 1960; 1961). The basin 

formed on the southwest margin of the ancestral Uncompahgre uplift, 

which provided a local source of clastic material. The finer fraction of 

the clastic material was intermittently spread across the entire basin 

as 'an euxinic mud between each of the 29 evaporite cycles of the saline 

facies. Microscopic examination of the organic matter indicates it 

occurs as thin films surrounding mineral grains. Oil and gas are reported to be commonly associated with the black-shale beds, which 

suggests that the organic matter was probably chiefly sapropel.
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G9

CHEMICAL METHODS OF ANALYSIS

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). Kesults 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, and 

so on, and are reported arbitrarily as midpoints of these intervals, 

using the numbers 1, 0.7, 0.5, 0.3, 0.2, 0.15, 0.1, and so on. The precision 

of a reported value is approximately plus or minus one interval at 68 

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

carbonate minerals after the methods outlined by Tourtelot, Huffman, 

and Kader (1964, p. D74). Organic carbon was calculated by taking 

the difference between total carbon >and carbonate carbon. On some 

samples, several chemical analyses were made to determine the content 

of certain constituents MgO, CaO, Na2 0, K2O, Li, Zn, Cl, and S for 

set 8; P2O5 and S'e for set 6; and U for set 7. Eadioactivity was measured for samples in sets 6 and 8 and expressed as eU (equivalent 

uranium), a measure of the radioactivity expressed as though uranium 

in equilibrium with its daughter products were the only source.

STATISTICAL METHODS

Statistical analyses of the four sample sets were conducted in much 

the same manner as was described in a previous report (Vine 1966a). 

The 5th, 25th, 50th, 75th, and 95th percentiles 'and the arithmetic and 

geometric means were calculated for each variable, and the product 

moment coefficient of correlation was calculated for each pair of variables 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), the substitutions given in table 2 were 

made in the data sets before correlations were calculated.

The substituted values are somewhat arbitrary, but they are slightly 

less than the lower limit of spectrographic or chemical determinations 

and are thought to introduce less bias in the estimation of correlation 

statistics than would be introduced by the exclusion of samples for 

which indeterminate values were reported. If more than 25 percent of 

the analyses for any element were reported as indeterminate values, 

the element was not used in the correlation studies.

The interpretation of geochemical associations in the rock units 

studied is based primarily on coefficients of correlation for each pair 

of constituents (tables 4, 6, 8,10). The coefficients measure the degree 

to which log concentrations fit a straight line when plotted on a
G10 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 2. Substitutions made in data sets 5-8 

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

Corg

eU._

Element

Reported Value

Number of value substituted

samples (percent) (percent)

Set 5 <40 samples)

Ca

K -.___---._..-...

B ________________

Be... __--.------.-..

Co. . .-.-._.-_--..

Ga

La --_------_----.

Mo.--.-....-..-....

Sc

..-----.- 3 >

__________ 1

2

..._..-.- 1

--.--.... 5

.._----__. 1

--.----.- 1

-...----- 10

.-..-...- 1

'10

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

15

.5

. 0015

. 00007

.0002

.0007

.0015

. 0002

. 0003

Set 6 (43 samples)

M

K.g-._. ._.---.__...-

Ag . ... ...

Ga

La -.--.----.---.-

Sc_--_-------._-._-_

Zn.... ..............

1

*v.

-.--..--. 9

,._._ __ 1

---..._.- 1

_---_-..- 4

-.......- 8

_________ 6

>10 15

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

5

0001

00015

002

0003

015

Set 7 (51 samples)

Set 8 (25 samples)

<0. 2

<. 001

15

0.15

.0007

bivariate diagram, and the sign of the coefficient indicates whether 

the line of best fit has a positive or negative slope. If the bivariatefrequency 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, see Davies, 1954, p. 276.) Tables 5, 7, 9, and 11 list 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 ideal sampling of the rock unit was not 

fully realized.

Groups of associated elements are further identified from the correlation matrices by the use of principal-component analysis, a technique described by Harman (1960). The principal-component analysis
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES Gil

has recently been applied to a variety of geologic problems, some of 

which were described by Imbrie and VanAndel (1964) and by Griffiths (1966). The technique involves constructing radial vectors for 

each of the chemical constituents so 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 axes have been selected that will best represent most 

of the data in two dimensions.1 In two-dimensional 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 

variously shaded segments of each diagram suggest possible geochemical groupings of the elements. The resulting groups of elements are 

thought to be the result of different physical and chemical processes 

in the depositional environment and subsequent alteration of each 

rock unit. However, the data are part of a closed array, a factor which 

complicates the interpretation of the groups. This problem, described 

by Chayes (1960), can be thought; of as one of dilution. For example, 

the end members of such major rock constituents as detrital quartz, 

carbonate minerals, and clay can be regarded as pure siltstone, limestone, or shale that contains only one of the three constituents. A builtin negative correlation must necessarily exist between the dominant 

major constituent and the other two principal constituents. A corresponding positive correlation is imposed on some of the minor constituents that result entirely from the dilution process. The process 

of dilution is therefore a factor affecting the magnitude of any correlation coefficient given in tables 4,6,8, and 10.

DISTRIBUTION AND ASSOCIATION OF ELEMENTS

The distribution and association of elements is described separately 

for each sample set because each set is different with respect to lithology, environment of deposition, and sampling technique. Consequently, each set is geochemically different. The amount of each element or other constituent in the sample sets is listed in table 3, and 

the coefficient of correlation calculated for each pair of constituents 

is listed in tables 4, 6, 8, and 10. The lists of element associations 

(tables 5, 7, 9, 11) and the vector diagrams constructed from the correlation data (figs. 2-5) aid in understanding and interpreting the 

element associations. In discussions of the relative abundances of the 

major elements, the elements normally detected by the six-step spec1 Examination of the eigenvalues of the correlation matrices, and of communialltles of 

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

principal components with any acceptable degree of certainty.
G12 CONTRIBUTIONS TO GEOCHEMISTRY

trographic method and the chemically determined organic carbon and 

mineral carbon are considered. Where such elements as silicon, aluminum, calcium, magnesium, and phosphorus are reported in concentrations greater than 10 percent, the precise concentrations in the 

individual samples are unknown; but in some sample sets the median 

abundances can still be estimated (table 3). Cmm (carbonate carbon) 

is a major constituent in two sets and is an insignificant constituent 

in the other two sets.

FENNSTLVANIAN BLACK SHALES FROM KANSAS AND OKLAHOMA

Major elements. More than 10 percent silicon was reported from 

all but a few samples of black shale in set 5. Silicon is probably the 

most abundant element after oxygen. Carbon, with a median content of" 

15 percent, is probably the next most abundant element. The carbon is 

assumed to be chiefly of organic origin; mineral carbon content is negligible. The median contents of the other major elements are aluminum, 

7 percent; potassium, 2 percent; iron, 1.5 percent; calcium, 1.5 percent; 

magnesium, 0.7 percent; sodium, 0.7 percent; and titanium, 0.1 percent.

Minor elements. The minor-element distribution for the black 

shales in sample set 5 is similar to that in other black shales associated 

with coal beds in the Interior coal province. However, compared with 

the previously studied black shales from the western Kentucky coal 

field (Vine, 1966a), the 0.03-percent median chromium content is high. 

At the 95th percentile the contents of strontium, lead, vanadium, 

nickel, and zinc are also high. Conversely, the high molybdenum values 

that seemed to characterize the black shales from Kentucky were not 

found here.

TABLE 3. Element content in four sets of Paleozoic black-shale samples

[Chemical analyses were made to determine MgO, CaO, NajO, KsO, Li, Zn, Cl, and S for set 8; PsOj and 

Se for set 6; and U for set 7. Radioactivity was measured and expressed as eU (equivalent uranium) for 

sets 6 and 8. Parentheses indicate that content of element was recalculated to elemental form. All other 

analyses were made by the semiquantitative spectrographic method described on p. O9. See p. Q3 for list 

of analysts]

Element or Sftt Values, in percent, for indicated percentile Arithmetic Geometric 

constituent oet Pj Pjj PM p?j p>5 mean mean

Si.............. 5

6

7 

8 

Al._ ............ 5

6

7 

8

Fe.............. 5

6

7 

8

7

1.5 

>10

1.5 

5

.3

7 

.7

.7

.3

2

.7

>10

3

7

1.5 

7 

3

1

.7 

2 

1

>10

7

7

1.5 

7 

5

1.5

.7 

3 

1

>10

>10 

>10

7

3

7 

7

2

1.5 

3 

1.5

>10

>10

>10

3 

7 

3

2 

5 

2

8.1

12.2

1.8 

7.9 

4.7

1.6

1.1 

2.8 

1.3

6.4

11

1.5 

7.6 

4

1.5

.92 

2.7 

1.2
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G13 

TABLE 3. Element content in four sets of Paleozoic black-shale samples Continued

Element or 

constituent

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

MgO............

(Mg).........

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

CaO. ...........

(Ca)........

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

NazO.... .......

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

K2O. ...........

(K).........

Tl. .............

P...............

PaOj............

(P).. .......

P...............

Mn..---.. ......

CtotaU. .........

C m ineral.. .......

Cl.. ............

8...............

Ag... ...........

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

Ba..... .........

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

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

Set -

5 

6

7 

8

5 

6

7 

8

5 

6

7 

8

5 

6

7 

8

5 

6

7 

8

5 

6

7 

8

5 

6

7 

8

5 

6

7 

8

6 

8

6 

8

8 

8

5 

6

7 

8

5 

6

7 

8

5 

6 

7 

8

5 

6

7 

8

5 

6 

7 

8

Values, in percent, for indicated percentile Arithmetic Geometric

P«

0.3 

.2 

.7 

4.9 

(3.0)

.15 

5 : 

.015 

4 

(2.9)

.2 

.3 

.3 

.21 

(0.16)

1.5 

.5 

3 

.75 

(0. 62)

.07 

.02 

.15 

.03

1.5 

(0. 65)

.002 

.0015 

.005 

.01

1.5 

3 

2 

3.3

.7 

.99

1

<.0001 

.0002 

<.0001 

<.0001

.0015 

<.003 

.005 

.003

.015 

.005 

.02 

.005

.0001 

<. 00015 

.00015 

<.0001

.0002 

<.0007 

.001 

<.0005

P»

0.7 

.7 

.7 

5.6 

(3.4)

.7 

>10 

.16 

9.9 

(7.1)

.3

.5 

1 

.42 

(0.31)

2 

1 

3

2.2 

(1.8)

.10 

.07 

.15 

.07

7 

(3.1)

.007 

.005 

.01 

.015

5 

7 

7 

4.9

1 

2.9

3

.8

1.5

<.0001 

.0005 

<.0001 

<.0001

.002 

 C003 

.007 

.005

.02 

.007 

.02 

.015

.00015 

<. 00015 

.0002 

<.0001

.0005 

<.0007 

.0015 

 C0005

PBO

0.7 

1.5 

.7 

6.9 

(4.2)

1.6

.3 

17 

(12)

.7 

.7 

1 

.68 

(0.50)

2 

2 

3 

2.5 

(2.1)

.1 

.1 

.2 

.1

.5 

15 

(6.5)

.01 

.01 

.01 

.015

15 

10 

10 

6.7

3 

4

5 

2.1

2 

.15

.00015 

.001 

<.0001 

<.0001

.003 

<.003 

.007 

.01

.02 

.01 

.03 

.02

.00015 

<. 00015 

.0002 

<.0001

.0007 

<.0007 

.002 

.0005

P»

0.7 

3 

1 

9.5 

(5.7)

3

.7 

20 

(14)

.7 

1 

1 

.97 

(0. 71)

2 

2 

3 

3.1 

(2.6)

.15 

.15 

.2 

.1

.7 

30 

(13)

.02 

.015 

.015 

.015

15 

10 

15 

7.8

5 

6.2

7 

2.9

5 

.7

.0002 

.0015 

<.0001 

<.0001

.003 

.005 

.007 

.015

.02 

.015 

.03 

.03

.0002 

<. 00015 

.0003 

.0001

.001 

<.0007 

.003 

.0005

P«

1 

7 

1.6 

17 

(10)

15

1

24 

(17)

1

1.5 

1 

5.9 

(4.4)

3 

3 

3 

5 

(4.2)

.2 

.2 

.2 

.15

1.5

30 

(13)

.05 

.02 

.03 

.02

20 

15 

15 

9.9

7 

9.1

15 

3.4

7 

3

.0007 

.002 

.0001 

<.0001

.005 

.015 

.01 

.02

.05 

.02 

.05 

.05

.0002 

.00015 

.0003 

.00015

.001 

.0007 

.005 

.0007

mean

0.71 

2.5 

.80 

8.6 

(5.2)

2.9

.51 

16 

(ID

.64 

.80 

.90 

1.2 

(0.89)

2.2 

1.7 

3.2 

2.7 

(2.2)

.13 

.11 

.19 

.084

17.5 

(7.6)

.014 

.011 

.012 

.015

16 

9 

10 

6.4

3.2 

4.5

5.8 

2.0

.00097

.0031 

.0034 

.0069 

.010

.025 

.012 

.030 

.023

.00018

.00024

. 00073

.0022

mean

0.66 

1.5 

.78 

7.9 

(4.8)

1.7

.24 

15 

(11)

.66 

.72 

.82 

.76 

(0.66)

2.1 

1.4 

3.2 

2.5 

(2.1)

.12 

.094 

.19 

.080

13.5 

(5.9)

.0095 

.0086 

.011 

.014

8.6 

8.3 

8.8 

6.1

2.2 

3.9

4.6 

1.5

.00081

.0030 

.0025 

.0066 

.0090

.023 

.011 

.029 

.020

.00017

.00024

.00064

.0021

329-581 O 69 3
G14 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 3. Element content in four sets of Paleozoic black-shale samples Continued

Element or Ooi.

constituent bel

Cr.. ........

Cu..........

Ga..........

La.........

Li.........

Mo.........

Nd. ........

Ni

Ph.. ......

SQ... .......

Se.. .......

Sr.. .......

V..........

Y.... ......

Yb.... .

eU... ......

U..........

Zn... ......

Zr.. .......

..... 5

6 

7 

8

..... 5

6

7 

8

..... 5

6 

7 

8

..... 5

6

7 

8

..... 8

..... 5

6

7 

8

..... 6

..... 5

6 

7 

8

..... 5

6

7 

8

..... 5

6

7 

8

..... 6

..... 5

6

7 

8

..... 5

6 

7 

8

..... 5

6 

7 

8

..... 8

..... 6

8

..... 7

..... 5

6

7 

8

. .. 5

6

7 

8

Values, in percent, for indicated percentile Arithmetic Geometric

Pt

0.007 

.02 

.005 

.005

.002 

.003 

.007 

.0007

.001 

.0002 

.0015 

.0005

.002 

.002 

.003 

.001

.0026

.0002 

.001 

.0015 

 C0005

<.015

.0015 

.002 

.007 

.0015

.001 

<.001 

.002 

<.001

.0007 

.0003 

.001 

 C0007

.002

.015 

.03 

.007 

.015

.007 

.007 

.015 

.002

.0015 

.002 

.003 

.001

.0001

<.001 

<.001

.0007

<.03 

.015 

<.03 

.0008

.002 

.003 

.007 

.001

P2»

0.01 

.07 

.007 

.005

.005 

.005 

.01 

.001

.001 

.0007 

.0015 

.0007

.003 

.005 

.003 

.002

.0032

.0002 

.002 

.003 

<.0005

<.015

.005 

.01 

.007 

.0015

.002 

<.001 

.002 

<.001

.001 

.0007 

.001 

.0007

.003

.015 

.07 

.01 

.02

.01 

.02 

.015 

.005

.002 

.007 

.003 

.0015

.0002

.002 

.001

.003

<.03 

.07 

<.03 

.0019

.003 

.005 

.01 

.003

PM

0.03 

.1 

.007 

.007

.007 

.007 

.01 

.002

.0015 

.0015 

.002 

.0015

.003 

.01 

.003 

.003

.0043

.001 

.005 

.007 

 C0005

<.015

.01 

.015 

.01 

.003

.003 

.001 

.003 

.001

.001 

.0007 

.0015 

.0007

.007

.02 

.1 

.01 

.05

.015 

.05 

.015 

.005

.003 

.015 

.003 

.0015

.0002

.005 

.002

.005

<.03 

.15 

<.03 

.0034

.005 

.007 

.01 

.005

P?»

0.05 

.15 

.007 

.02

.01 

.01 

.015 

.003

.002 

.002 

.002 

.0015

.005 

.02 

.005 

.005

.0066

.002 .01' 

.01 

<.0005

.015

.015 

.02 

.01 

.005

.005 

.0015 

.003 

.001

. 0015 . 

.001 

.0015 

.001

.01

.02 

.2 

.015 

.07

.05 

.10 

.02 

.007

.003 

.02 

.005 

.003

.0002

.01 

.003

.007

.05 

.3 

<.03 

.0053

.007 

.01 

.01 

.007

P«5

0.05 

.7 

.01 

.03

.01 

.03 

.015 

.005

.002 

.003 

.002 

.003

.005 

.07 

.005 . 

.005

.0085

.005 

.02 

.01 

.0007 .

.03

.02 

.07 

.015 

.007

.01 

.002 .

.005 

.005

.002 

.002 

.002 

.0015 .

.015

.05 

.3 

.02 

.1

.07 

.2 

.05 

.01

.005 

.07 

.005 

.003

.0003

.02 

.004

.01 

.1

1 

.03

.011

.01 

.02 

.015 

.01

mean

0.029 

.15 

.0069 

.013

.0070 

.010 

.012 

.0022

.0016 

.0013 

.0020 

.0013

.0038 

.015 

.0037 

.0030

.0050

.0017 

.0074 

.0071

.011 

.020 

.0089 

.0035

.0041

.0031 

.0011

.0012 

.00088 

.0014

.0070

.022 

.13 

.012 

.046

.026 

.063 

.020 

.0060

.0031 

.020 

.0037 

.0023

.00019

.0071 

.0020

.0051

.22

.0048

.0051 

.0081 

.010 

.0055

mean

0.022 

.099 

.0067 

.010

.0062 

.0098 

.011 

.0019

.0015 

.0010 

.0019 

.0012

.0037 

.010 

.0037 

.0026

.0046

.00095 

.0049 

.0057

.0088 

.015 

.0086 

.0030

.0033

.0030 

.00094

.0011 

.00076 

.0013

.0056

.021 

.11 

.012 

.038

.019 

.042 

.019 

.0056

.0030 

.013 

.0036 

.0022

.00018

.0044 

.0017

.0041

.13

.0035

.0044 

.0071 

.010 

.0047
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G15

Correlation data. The vector diagram (fig. 2) and the correlation 

coefficients and element associations (tables 4 and 5) suggest the possibility of grouping the elements reported from the Pennsylvania!! black 

shales of Kansas and Oklahoma into four major groups. Elements in 

each group tend to have a strong positive intercorrelation. Chromium, 

nickel, copper, molybdenum, lead, vanadium, and calcium are thought 

to be associated chiefly with organic matter and are in the group that 

includes Corg (organic carbon). The group with organic carbon also 

tends to have a negative correlation with the group that includes titanium, zirconium, boron, gallium, and scandium. This second group contains many of the elements that commonly occur in detrital minerals, 

and so it may be regarded as a detrital-mineral group. In the third and

FIGURE 2. Rotated two-dimensional vector diagram showing the principalcomponent analysis of the correlation matrix for set 5, 40 samples of Pennsylvanian black shales from Kansas and Oklahoma. Patterned areas suggest 

geochemical groupings of elements.
G16 CONTRIBUTIONS TO GEOCHEMISTRY

2 5 2 3 3 «.

r r r r r

88388232

II II

^e

O

13

e

a

1

*

8

*5 35

I I

O5 O CM i-H 

l» i-l i-l i-l

o t «o <i o o>

il O i-l O il <i s s § s s

|1 00 CO

2 S 8 2 S S S

r ' ' ' ' ' r

S S 2 S

v=,

i- 1-1 o t» >-i ej 1-1 

co co »»< t- »(< cb co

e 

-«

o-*

 a o o

2SSSSSS28

r r ' ' ' r

S S S

CO i-l il

I I

0 r-l CM

S 8

2 S g

I I I

S S 5 3

l I 

2 § S § S

S

CO 

^H

f

1 1

S i-i 2

4

42

f

CO CO t>- i-l 

CO 'Jl «O IN

s §

S

co 1-H

J 

m

H

S

OS U5

S §3
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G17

TABLE 5. Element associations in set 6, 40 samples of Pennsylvanian black shales 

from Kansas and Oklahoma

[ 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 < 

Ca, C, Cu, Mo

Ca, C. Cu, Pb

C, Ca, Mo, Cu, V

C, Ca, Cu

Ca, C

C, Ca, V, Mo

C

Zr, Ti, Ga, Sc, B, Be

Qa, B

Zr, Ti, Ga, Sc

Ga, B, Ti

Zr

Zr, Sc, Ga, Ti, B, La, Be

Element

Ti

Zr

Qa

Sc

Be

B

Ba

Fe

Mn

La

Y

Co

K

Mg 

Na

Sr

Ca

V

Cu

Cr

Mo

Ni

Pb

C

T> <K ! *1

Mn, Ba, Fe, B, K, Be, La, Ga, Sc, Zr

Fe, Ba, K, B, La, Be, Ga, Sc, Ti

Mn. Ba, La, K, Sc, Be, B, Zr, Ti

Fe, Mn, Ba, Co, Mg, B, La, K, Ga, Be, Zr, Ti

Fe, Mn, Ba, Mg. La, Co, B, K, Ti, Zr, Ga, Sc

Na, Co, K, La, Ti, Be, Sc, Zr, Ga

Cr, Y , Sc, Fe, Be, Ga, Mg, Zr, Ti, La, K

Be, Sc, Mn, Mg, Zr, Ba. K, Ti

Qa, Sr, Fe, Sc, Be, Ti, Co, K, Mg

Na, Mg, Be, Y, B, Ga, Ba, K, Sc, Zr. Ti

K TJo Qv T a

, i5a, or. LA 

B, K, Mg, Sc, Be, Mn

Sr, Co, Cr. Y , Ni, Fe, Na, B, Mn, Zr, Ga, La, Be, Ti, Ba, Sc, Mg

Mo, Cu, Co, Fe, La, V, Sc, Be, Sr, Ba, Cr, Mn, Na, Ni, K 

Mo, B, La, K, Cr, Pb, Cu, Ni, Mg

Cu, K, Mn. Ca, V, Y, Mg

Pb, Mo, Ni, Sr, C, Cu

C, Mg, Sr, Pb, Cu. Ni, Cr, Mo

Sr, Mg, Na, V, C, Ca, Pb, Cr, Ni, Mo

Ba, K, Na, C, Mg, Pb, Cu, Ni, Mo, V

Na, Ca, Mg, C, Pb, Cu, Ni, Cr, V

Ca, K, Na, C, V, Pb, Cu, Mg, Mo, Cr

Ca, Na, V, Cu, Cr, Mo, Ni, C

V, Cr, Ca, Cu, Mo, Ni, Pb

fourth groups the elements are not so easily interpreted because individual elements correlate positively with individual elements in the 

first two major groups. Some of the elements for example, manganese, iron, and cobalt are close to or less than 0.5 unit radius and do 

not really closely correlate with the other elements in their group. The 

fact that these two groups have strong ties to both the other groups 

may be due in part to the problem of the closed array. Mineralogically, 

these elements seem to represent a mixture of diverse components, such 

as phosphate nodules, clay minerals, and weathering products. Phosphate nodules may be enriched with strontium, yttrium, and lanthanum. Clay minerals may account for some of the potassium, 

magnesium, and sodium. Pyrite and weathering products such as 

hydroxides and sulfates probably account for most of the iron and 

such elements as barium, cobalt, and manganese.

PERMIAN MEADE PEAK PHOSPHATIC SHALE MEMBER OF THE 

PHOSPHORIA FORMATION

Major elements. The samples from the Meade Peak Phosphatic 

Shale Member of the Phosphoria Formation that make up set 6 range 

in lithology from phosphorite, to carbonate rock, to siltstone. Therefore, the distribution of elements between several different rock components can be examined in set 6. Calcium is the major element in 

three of the principal rock-forming minerals calcite, dolomite, and 

carbonate-fluorapatite and it composes more than 10 percent of most 

of the samples. The other major elements, in order of decreasing
G18 CONTRIBUTIONS TO GEOCHEMISTRY

abundance, are phosphorus, silicon, potassium, aluminum, magnesium, 

iron, and sodium.

Minor elements. A remarkable number of minor elements occur in 

abnormally high concentration in the Meade Peak Member, as 

was noted by Gulbrandsen (1960, p. 82). The concentrations of the 

following minor elements are especially high:

95 perElement Median centilt

Ag_____..._.._....__..--.-. 0.001--.._.._...._.._._-- 0.002

Cr......._..........._._ .1........._....._...... .7

Ni....__.__......_..._-.-._ .015__-_...---.---.-.--- .07

Se__..................-.-._ .007____._.__.._...-.... .015

Sr_________________________ .l-___-__________.___-_- .3

V_._____-_________________. .05_--___________-_---_- ».2

Y_________________________ .015_________----_-.___- .07

Zn__.______________________ .15_____-._______-___-_- 1.0

1 Oulbrandsen (1960, p. 84) stated that the vanadiferous zone, 3.5 feet thick, at Coal Canyon, Wyo. 

contains an average 0.7 percent V2 05 (equivalent to about 0.39 percent elemental vanadium).

Manganese, boron, gallium, molybdenum, scandium, and zirconium 

occur in concentrations more nearly typical of black shales and associated carbonaceous rocks. Other elements occur in relatively low 

concentrations in the Meade Peak Member. For example, the 95th 

percentile concentration of barium is only 0.02 percent, less than half 

the average concentration in shale, as reported by Turekian and Wedepohl (1961, table 2). Concentrations of beryllium, cobalt, and lead are 

also relatively low; yet these elements are among those that Krauskopf 

(1955, p. 417,423) found to be commonly enriched in both black shales 

and phosphorites, and lead is among the elements he described to be 

markedly enriched in black shale (Krauskopf, 1955, p. 419).

Correlation data,. The range in lithologic types included in the 

samples of the Meade Peak Member is reflected in the correlation data 

(tables 6 and 7). However, most of the elements detected can be assigned to four major components represented by C0 rg, Cm in, P2O5 , and 

silicon, (see fig. 3.) These four components can be regarded as characteristic of four different end members of the Meade Peak lithologies and 

probably include all the more significant rock components, with the 

possible exception of sulfide minerals. The group characterized by 

silicon and including aluminum, titanium, zirconium, gallium, boron, 

barium, and iron is thought to represent the detrital end member. 

The phosphorite end member is characterized by P2 05 and includes 

strontium, yttrium, and the radioactive elements expressed as ell 

(equivalent uranium). The carbonate end member, characterized by 

Cmin, includes magnesium and manganese. It presumably includes calcium as well, but analytical data for this element are not available. The 

group characterized by Corg is made up of selenium, copper, nickel, 

scandium, molybdenum, and chromium, which show strong intercorrelations with each other and with Corg. They also show moderate
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G19

FIGURE 3. Rotated two-dimensional vector diagrann showing the principalcomponent analysis of the correlation matrix for set 6, 43 samples from the 

Meade Peak Phosphatic Shale Member of the Phosphoria Formation. Patterned 

areas suggest geochemical groupings of elements.

correlations with elements in the detrital groups. Vanadium, lanthanum, and zinc correlate strongly with each other and with C0rg ; 

they also correlate moderately strongly with the elements in the phosphorite end member. Thus, the elements associated with organic matter 

tend to fall into several subgroups, according to whether they are more 

closely related to phosphorite or to siltstone. The carbonate end 

member tends to correlate negatively with the other groups, presumably 

because of the dilution effect of the carbonate rocks.

UPPER DEVONIAN CHATTANOOGA SHALE

Major elements. In many ways the Chattanooga Shale samples of 

set 7 are typical of black shales in general. The content of most of the
G20 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 6. Correlation coefficients for element pairs in set 6, 43 samples of black shale,

Phosphoria

Si

Si

Al

0.80

Al

Fe

0.72 

.85

Fe

Mg

0.12 

-.04 

-.06

Mg

Na

0.07 

.15 

.09 

-.09

Na

K

0.66 

.61 

.54 

.59 

-.06

K

Ti

0.80 

.84 

.84 

-.13 

.18 

.54

Ti

Mn

0.48 

.33 

.35 

.69 

.16 

.64 

.30

Mn

Ag

0.48 

.64 

.60 

-.05 

-.18 

.49 

.51 

-.05

Ag

B

0.62 

.64 

.68 

.02 

-.13 

.50 

.63 

.29 

.33

B

Ba

0.71 

.80 

.75 

-.39 

.20 

.33 

.86 

.12 

.47 

.63

Ba

Or

0.07 

.42 

.42 

-.56 

-.10 

-.12 

.27 

-.43 

.64 

.20 

.46

Cr

Cu

0.24 

.57 

.58 

-.39 

-.05 

.16 

.45 

-.25 

.77 

.37 

.67 

.87

Cu

Ga

0.56 

.53 

.43 

.31 

-.28 

.67 

.41 

.19 

.70 

.49 

.27 

.13 

.41

Ga

La

-0.15 

.06 

.16 

-.60 

-.21 

-.42 

.00 

-.55 

.40 

.05 

.20 

.80 

.62 

-.01

La

Level of significance:

9 percent

0.39

99.9 percent

0.49

1 Ct, total carbon.

2 Cm in, carbonate carbon.

3 Corg, organic carbon.

major elements probably falls close to the median for black shales. 

Furthermore, the major elements, except for calcium, show a restricted 

range in values between the 5th and 95th percentiles (table 3). Presumably, this restriction reflects the remarkable uniformity of the 

Chattanooga Shale over a widespread area. Standard rock analyses 

for three outcrop samples of the Chattanooga Shale that are probably 

representative of the formation.in central Tennessee were listed by 

Conant and Swanson (1961, p. 43).
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G2'l

dolomite, and phosphorite from the Meade Peak Phosphatic Shale Member of the 

Formation

Mo

0.38

.62

.63

-.27

-.13

.16

.43

-.16

.48

.42

.49

.55

.63

.35

.26

Mo

Ni

0.28

.68

.56

-.39

-.28

.15

.43

-.26

.70

.43

.54

.86

.85

.39

.60

.73

Nl

Sc

0.42

.60

.59

-.55

-.03

-.03

.57

-.27

.56

.45

.69

.75

.69

.28

.67

.51

.68

Sc

Sr

-0.38

-.25

-.23

-.68

-.23

-.63

-.34

-.72

.10

-.32

-.04

.55

.34

-.19

.66

.26

.39

.36

Sr

V

-0.01

.19

.16

-.62

-.15

-.27

.13

-.54

.41

.10

.35

.66

.61

.13

.49

.69

.69

.61

.65

V

Y

-0.27

-.01

.08

-.73

-.14

-.57

-.07

-.68

.28

-.10

.16

.79

.57

-.16

.93

.27

.54

.65

.78

.56

Y

Zn

0.02

.14

.07

-.49

-.28

-.19

.03

-.48

.45

.07

.30

.65

.53

.14

.60

.56

.66

.48

.65

.79

.53

Zn

Zr

0.67

.57

.57

-.36

.15

.19

.76

.11

.21

.54

.79

.14

.27

.24

.04

.38

.26

.59

-.09

.26

.03

.12

Zr

eU

-0. 15

.01

-.05

-.77

-.08

-.54

-.09

-.62

.14

-.14

.24

.53

.35

-.16

.49

.38

.47

.39

.75

.74

.63

.66

.19

eU

PsOs

-0.35

-.27

-.24

-.62

-.11

-.63

-.31

-.73

.16

-.42

-.05

.58

.31

-.23

.70

.15

.38

.34

.84

.57

.81

.62

-.15

.73

PiOj

Se

0.17

.48

.61

-.30

.11

.21

.38

-.08

.63

.31

.40

.68

.79

.31

.38

.52

.68

.44

.13

.45

.35

.32

.17

.19

.18

Se

C,i

-0.10

.17

.20

.28

-.25

.33

-.04

.15

.38

.11

-.20

.30

.41

.38

.15

.28

.39

.01

-.08

.06

.05

.02

-.39

-.32

-.12

.48

c,

Cm In'

0.08

-.07

-.01

.87

-.09

.53

-.10

.77

-.14

.02

-.36

-.54

-.41

.14

-.61

-.32

-.38

-.57

-.69

-.64

-.67

-.55

-.37

-.76

-.65

-.21

.38

Cmln

Cor,8

0.01

.37

.39

-.32

-.17

.05

.27

-.39

.64

.19

.31

.82

.83

.31

.56

.57

.84

.51

.39

.60

.57

.53

.05

.34

.43

.76

.59

-.37

Minor elements. Like the major elements, most minor elements in 

sample set 7 occur in concentrations fairly typical of black shales in 

general. The minor elements also show great uniformity over a wide 

area. Uranium and cobalt, however, are exceptions; they occur in 

greater concentrations than is typical of black shales. The median 

cobalt content of 0.002 percent is about three times greater than was 

noted in previously studied black shales. The median uranium content 

of about 0-005 percent is more than 10 times the concentration of
G22 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 7. Element associations in set 6, 43 samples of black shale, dolomite, and 

phosphorite from the Meade Peak Phosphatic Shale Member of the Phosphoria 

Formation

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

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

Negative correlation < - 

eU, Sr, Y, PjOs, V, Sc, Zn, Cr, La, Cn,

Ni, Con, Zr, Ba, Mo 

eU, Y, Sr, PjOj, V, La, Cr, Sc, Zn, Ba,

Cu, Ni, Zr, Se, Con

PjOj, Sr, Y, eU, La, V, Zn, Cr, Con

PaOs, Sr, Y, eU, La

Mg, Cmin

C m in, Mg

Sr, PsOs

Sr, PjOs

PzOs, Sr

Cmln

Mg

Cmln, Mg

Mg, Cmin

Mg, Cmin

Mn, Cmin, Mg

Mg, Cmin, Mn

Cmin, Mg, Mn

Cmin, Mg, Mn

Mg, Mn, Cmin, K

Mg, Mn, Cmin, K

Mg, Cmin, Mn, K

Mn, Cmin, Mg, K. Si, Ti, B

Cmin, K, Mg, B, Si, Ti

Element

Cmin

Mg

Mn

Na

K

Ba

Zr

Si

Ti

B

Al

Fe

Qa

Ag

Mo

Se

Cu

Ni

Sc

C0,g

Cr

V

Zn

Y

La

eU

Sr

P2Os

 » Positive correlation

K. Mn. Mg

Ga, K, Mn, Cmin

Ti, Al, Fe, Si, K, Mg, Cmin

Ba, Ag, B, Cmin, Fe, Ti, Mg, Al, Mn, Si, Ga

Zn, Co, K, Y, Se, Cr, Ag, Mo, Ni, Cu, B, Sc, Si, Fe, Zr,

Al, Ti

Mo, B, Al, Fe, Sc, Si, Ti, Ba

Mo, Sc, Mn. Ag, Ga, B, K, Zr. Ba, Fe, Al, Ti

Mn, Se, Ga, Mo, Ni, Cu. Ag. K, Sc, B, Zr, Si, Al, Fe, Ba

Se, Ag, Cu, Mo, Ni, Sc, Ga, K, Zr, Si, Ti, Ba, Al, Fe

Con, Cr, Se, Ga, Zr. Cu, Mo, Ni, Sc, K, Ag, B, Si, Ba,

Ti,Fe

Mn, Con, Cr, Ga, Mo, K, Ni, Zr, Co, Sc. Ag. Se, B, Si,

Ba, Ti, Al

Mg, Se, Con, Mo, Nl, Cn, Ti. Fe, B, Al, Si, K, Ag

B, La, V, Zn, Ba. Mo. Si. K, Ti. Sc. Fe. Se, Al. Cr,

Con. Ni, Ga, Cu

Ga, Zr, eU, Si, Ti, B, Ag. Ba. Sc. Se. Al. Fe. Cr, C0r(.

Zn, Cu, V, NI

B, Qa, Zn, Y, La, Ti, Ba, Sc, V, Al, Mo, Fe, Ag, Cr, NI,

Con, Cu

PjOs, Sr, eU, B, Ga, Ti, Zn, Al, Y, Ba, Fe, V, La, Mo,

Sc, Ag, Se. Con, NI, Cr

PjOs, Sr. Ga. Ti. B. eU. Ba, Y, Fe, Al, La, Zn, Sc. Se.

V, Mo, Ag, Con, Cu, Cr

PtOt, Sr, eU, Si, Se, B, Zn, V, Con. Mo, Ag, Ti, Fe,

Zr, Al, Y. La Ni. Cu, Ba, Cr

Ba, Ga, eU, Al, Fe, Sr, P8OS, Sc, Zn, La, Mo, Y, V, Ag,

Se, Cr. Cu, Ni

Al. Fe, Ba, eU, Sr, Mo, PjOj. Ag, Zn, V, Se, Sc, Y, La.

Con, Ni, Cu

Ba, Ag, Se, La, Sc, Y, PnOs, Con, Cu, Cr, Sr, Mo, Ni.

eU, Zn

Ba, Se, Ag, Sc, La, Y, Con, Cu, Mo, PjOs, Cr, Sr, eU,

NI, V

Se, Zn, V, NI, Cu, Con. eU. Sc, Sr, Cr, PjOj, La

Se, Ag, Zr, V, eU, Zn, C0 n, Ni. Cu, Sr, Sc, PsOs, Cr, Y

Cu, Con, Mo, Sc, Ni, La, Cr, Y, Zn, P2O}, V, Sr

Cu, Sc, Ni, Con. Cr, Zn, La, V, eU, Y, P?Os

Cu, Sc, Ni, Con, V, Cr, Zn, La, eU, Y, Sr

uranium in the average shale, as reported by Turekian and Wedepohl 

(1961).

Correlation data. The correlation data (tables 8 and 9; fig. 4) indicate that most of the elements are associated with one of four major 

groups, only three of which are reasonably compact.

1. The group characterized by Corg includes molybdenum, nickel, 

cobalt, uranium, and iron, all of which show strong positive intercorrelations. These elements may be directly associated with organic matter or with pyrite that is associated with organic matter.

2. The group that is characterized by aluminum includes magnesium, 

scandium, boron, strontium, beryllium, and chromium and, possibly, gallium and lanthanum. All these elements show a strong 

positive intercorrelation and are fairly typical of the elements 

associated with the detrital-mineral fraction of the rock.
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G23

FIGURE 4. Rotated two-dimensional vector diagram showing the principalcomponent analysis of the correlation matrix for set 7, 51 samples of Chattanooga Shale. Patterned areas suggest geochemical groupings of elements.

8. Calcium, magnesium, and sodium form a third group of unknown, 

possibly authigenic origin.

4. Zirconium is the most characteristic of a f ourth group that may include heavy resistates. The principal elements of the organic 

group tend to correlate negatively with the principal elements 

of the detrital group.

PENNSYLVANIA!! PARADOX MEMBER OF THE HERMOSA

FORMATION

Major elements. The samples from the Paradox Member of the 

Hermosa Formation are characterized by unusually large amounts of 

calcium and magnesium carbonates. The median carbonate mineral 

content is about 35 percent, and in some samples it is greater than 50
G24 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 8. Correlation coefficients for element

Al

Al

Fe

-0.44

Fe

Mg

0.79 

-.52

Mg

Ca

0.28 

.16 

.38

Ca

Na

0.18 

.38 

.27 

.84

Na

K

0.00 

.21 

.00 

-.07 

.06

K 

Level of significance:

95 percent

0.28

99 percent

0.36

Ti

0.16 

-.16 

.13 

-:36 

-.33 

.00

Ti

Mn

0.36 

-.03 

.56 

.84 

.74 

.05 

-.31

Mn

99.9 percent

0.45

B

0.56 

-.74 

.55 

.15 

-.03 

-.20 

.08 

.28

B

Ba

0.10 

-.22 

.01 

-.15 

-.23 

.00 

.21 

-.18 

.30

Ba

Be

0.43 

-.28 

.43 

.12 

.19 

.00 

.15 

.32 

.49 

.30

Be

Co

-0.36 

.70 

-.46 

.05 

.16 

.38 

-.23 

-.04 

-.52 

-.01 

-.19

Co

Cr

0.40 

-.66 

.59 

.03 

.00 

.00 

.19 

.17 

.66 

.07 

.43 

-.52

Cr

Cu

-0.30 

.15 

-.23 

-.29 

-.16 

.18 

.14 

-.15 

-.18 

-.40 

-.16 

.09 

.09

Cu

percent. Described individually, these samples would be called limestones and dolomites. Potassium and sodium are generally present 

in normal concentrations, although a few samples contain abnormally 

large amounts of sodium. Iron, titanium, and manganese are present 

in relatively low concentrations; and organic carbon, with a median 

value of 0.5 percent, is considerably less abundant than in typical 

black shales.

Minor elements. The median concentrations of most minor elements in the Paradox samples are low compared with those in other 

black-shale samples. Two notable exceptions are boron and strontium, 

which appear to be more abundant than in normal black shales. The 

high boron content may reflect the hypersaline environment (Degens
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G25 

pairs in set 7, 51 samples of Chattanooga Shale

Ga

0.33 

-.46 

.32

.04

-.03

-.14

.08 

.13 

.45 

.29 

.23 

-.35

.29 

-.35

Ga

La

0.33 

-.31 

.26

.16

-.10

-.14

.08 

.16 

.26 

.23 

.19 

-.21

.11 

-.34

.04

La

Mo

-0.71 

.52 

-.76

-.31

-.21

.00

-.29 

-.45 

-.62 

.02 

-.41 

.56

-.46 

.24

-.40

-.26

Mo

Ni

-0.30 

.26 

-.17

.08

.10

.10

-.45 

.13 

-.29 

-.28 

-.30 

.34

-.08 

.35

-.25

-.23

.41

Ni

Pb

-0.17 

-.09 

-.15

-.30

-.30

-.09

.17 

-.37 

-.13 

-.07 

.09 

-.18

.22 

.19

-.02

-.07

.15

.19

Pb

Sc

0.68 

-.50 

.59

.12

.05

.00

.36 

.21 

.66 

.18 

.64 

-.42

.54 

-.21

.55

.20

-.72

-.43

.05

Sc

Sr

0.47 

-.30 

.39

.44

.23

-.09

.20 

.31 

.52 

.16 

.27 

-.22

.36 

-.09

.04

.40

-.49

-.24

.12

.44

Sr

V

-0.05 

-.35 

-.06

-.16

-.23

-.49

_ 34 

-.20 

.28 

.20 

-.05 

-.36

.16 

-.13

.10

.05

.11

.28

.08

-.13

-.14

V

Y

-0.22 

-.17 

-.27

-.36

-.56

.12

.06 

-.42 

.02 

.26 

-.18 

-.06

.04 

.19

-.16

.37

.32

.08

.25

-.15

.09

.23

Y

Zr

-0.01 

-.40 

-.16

-.56

-.71

-.15

.40 

-.45 

.25 

.31 

.00 

-.28

.14 

.12

.01

.29

.04

-.31

.09

.15

-.03

.16

.47

Zr

U

-0.71 

.61 

-.79

-.23

-.08

.08

-.28 

-.40 

-.59 

.03 

-.31 

.61

-.50 

.19

-.33

-.33

.87

.37

.20

-.65

-.42

.01

.24

-.10

U

C

-0.69 

.55 

-.57

-.06

.10

-.05

-.39 

-.18 

-.60 

-.23 

-.32 

.36

-.34 

.17

-.19

-.43

.73

.46

.25

-.63

-.55

.06

.02

-.28

.79

and others, 1957). The high strontium content, however, probably reflects the high calcium content, with which it is commonly associated 

(especially in evaporite minerals), even though it does not show a 

very strong correlation with CaO.

Correlation data. A study of the correlation data (tables 10 and 

11) suggests four principal groupings (fig. 5) for the constituents of 

the black shales in the Paradox. The first group consists of Cm in, magnesium, calcium, and possibly manganese, the first three of which have 

a strong positive intercorrelation and a negative correlation with 

many constituents of the other groups. The second group is characterized by silicon, aluminum, vanadium, and titanium, all of which 

have a strong intercorrelation, and possibly also gallium, boron and
G26 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 9. Element associations in set 7, 51 samples of Chattanooga Shale

[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

Mo, U, C, Fe, Co, Ni, Cu

U, Mo, C, Fe, Co

Fe, Mo, C, U, Co, Ni

Mo, C, U, Ni, Fe

Mo, U, C, Fe, NI, Co

Mo, Fe, Co, Cu, U

C, Mo, U, Fe

Fe, Co, U, Mo, C

Na, Ca, Mn, Fe, Ni, Co, C

NI, C, Ca, V, Na, Mn, Mo, U

C, Fe, U, Cu

Na, Mn, Ca

Zr, Y, Ti, Pb

Mo, Zr, Y, U, Pb, Ti

Zr, Ti, Y, Mo, Pb, Cu

K, Co, Fe, Ti

V

Cu.Ni

Mn, Na, Ca

Ba, Ga. La, Al, Ca

B, Cr, Mg, Sc, Ga, Al, Zr, V, La, Sr, Be

Cr, B, Mg, V, Al, Oa, Zr

Ti, Sc. Zr, Al, Be, B, Ba

Mg, Sc, Al, B, Sr, Cr, Mn, Be, Ga, Ca, Ti

Mg, Al, Sc, Cr, B, Sr, Mn, La, Ga, Be, Ti

Al, Sc, B, Mg, Sr, La, Ti, Cr, Be, Zr

Al

Mg

B

Be

Sc

Qa

Sr

Cr

Zr

Ti

La

Y

Na

Mn

Ca

V

K

Ba

Pb

Cu

Fe

Co

Ni

Mo

U

C

Ca, Qa, La, Mn, Cr, Be, Sr, B, Sc, Mg

Oa, Ca, Sr, Be, B, Mn, Sc, Cr, Al

Mn, V, Ba, Ga, Be, Sr, Mg, Al, Sc, Cr

Ba, Mn, Cr, Mg, Al, B, Sc

Ti, Sr, Cr, Be, Ga, Mg, B, Al

Cr, Ba, Mg, Al, B, Sc

Mn, Cr, Mg, La, Ca, Sc, Al, B

Qa, Sr, Al, Be, Sc, Mg, B

La, Ba, TI, Y

Sc, Zr

Zr, Al, Y, Sr

Mo, La, Zr

Fe, Mn, Ca

B. Sr, Be, Al, Mg, Na, Ca

Al, Mg, Sr, Mn, Na

Ni, B

Co

Ga, Be, B, Zr

Ni

Na, Mo, C, U, Co 

Ni, C, K, Mo, U, Fe 

V, Co, Cu, U, Mo, C 

Y,Ni, Fe, Co, C, U 

NI, Co, Fe, C. Mo 

Co, Ni, Fe, Mo, U

iron. These may be regarded as the principal constituents of the detrital-mineral fraction. The third group with a strong positive intercorrelation includes C0 rg and the elements copper, zinc, nickel, chromium, lithium, lanthanum, yttrium, and ytterbium. A fourth group of 

uncertain geochemical significance includes barium, zirconium, sodium, and strontium. All these elements form soluble chlorides, and 

thus they may represent a group that has migrated in interstitial 

saline water. Potassium lies between this fourth group and the detrital 

group, which suggests a dual mode of occurrence.

SUMMARY AND CONCLUSIONS

Conventional geologic and petrographic data were supplemented by 

statistical analysis of chemical data to determine the distribution and 

association of minor elements in several types of marine black shale. 

The results appear to be sufficiently unbiased to be consistent with 

accepted principles of sedimentary geochemistry despite the deviations from ideal sampling patterns and the use of much semiquantitative data.

The statistical analysis of data shows that most elements can be 

assigned to one of the three major rock-forming fractions: the detrital 

mineral fraction, the chemically or biologically precipitated fraction, 

or the organic-matter fraction. In some sets of samples two groups of 

detrital elements occur, and in some sets a separate group that may
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G27

FIGUBE 5. Rotated two-dimensional vector diagram showing the principalcomponent analysis of the correlation matrix for set 8, 25 samples of black 

shale from the Paradox Member of the Hennosa Formation. Patterned areas 

suggest geochemical groupings of elements.

represent authigenic minerals is distinguished. The detrital-mineral 

fraction of these rocks generally includes silicon and aluminum (for 

which the data are incomplete), titanium, zirconium, boron, and, commonly, gallium, scandium, and beryllium. The Phosphoria and Paradox samples include carbonate rocks associated with the black-shale 

facies. In these sets calcium, magnesium, and manganese occur in a 

separate carbonate-mineral fraction inversely related to one of the 

other major mineral fractions. The organic-matter fraction correlates 

positively with the detrital-mineral fraction in these sets. The Chattanooga Shale samples and the samples of Pennsylvanian black shale 

from Kansas and Oklahoma did not include a significant carbonatemineral fraction. In these sets the organic-matter fraction appears to
G28 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 10. Correlation coefficients for element pairs in set 8, 25 samples

Si

Si

Al

0.86

Al

Fe

0.64 

.80

Fe

Ti

0.66 

.80 

.62

Ti

Mn

-0.11 

-.23 

-.21 

-.17

Mn

B

0.57 

.71 

.86 

.56 

-.39

B

Ba

0.66 

.57 

.13 

.59 

-.18 

.12

Ba

Or

0.41 

.65 

.86 

.47 

-.22 

.83 

-.09

Cr

Cu

0.48 

.68 

.78 

.49 

.02 

.72 

-.01 

.82

Cu

Oa

0.63 

.82 

.88 

.78 

-.20 

.83 

.28 

.79 

.79

Ga

La

0.14 

.40 

.56 

.28 

-.28 

.49 

-.14 

.59 

.41 

.48

La

Ni

0.56 

.70 

.81 

.46 

.09 

.72 

-.01 

.86 

.89 

.71 

.57

Ni

Pb

0.40 

.29 

.36 

.25 

.19 

.42 

.08 

.21 

.39 

.40 

.06 

.31

Pb

Sr

0.29 

.27 

-.18 

.34 

-.02 

-.32 

.70 

-.27 

-.06 

-.02 

-.30 

-.14 

-.26

Sr

V

0.78 

.89 

.84 

.70 

-.16 

.70 

.46 

.70 

.72 

.83 

.45 

.74 

.37 

.21

Level of significance:

95 percent

0.43

99 percent

0.55

99.9 percent

0.65

1 Ct, total carbon.

2 Cm in, carbonate carbon.

3 Corg, organic carbon.

be inversely related to the detrital-mineral fraction. This apparent difference in the behavior of the organic-matter fraction is thought to be 

due to either the dilution effect or the closed-array problem and is 

probably not the result of a geochemical process.

Identification of the suite of elements associated with the organicmatter fraction of each set is of particular interest in this study. This 

suite is most clearly identified where the organic-matter fraction is 

inversely related to the detrital-mineral fraction. The suite includes 

copper, nickel, vanadium, chromium, molybdenum, lead, and calcium
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G29 

of black shale from the Paradox Member of the Hermosa Formation

Y

0.12

.20

.43

.08

-.01

.49

-.44

.51

.27

.27

.63

.52

.25

-.65

.21

Y

Yb

0.46

.58

.71

.41

.02

.58

-.16

.73

.60

.56

.60

.78

.19

-.23

.54

.72

Yb

Zr

0.76

.52

.20

.41

.02

.20

.77

.09

-.01

.23

-.25

.05

.32

.33

.36

-.19

-.02

Zr

eU

0.46

.58

.46

.60

.09

.33

.46

.41

.61

.65

.13

.48

.29

.41

.61

-.25

.19

.31

Ue

CaO

-0.48

-.48

-.55

-.42

.31

-.73

-.33

-.41

-.29

-.56

-.17

-.27

-.36

.34

-.38

-.20

-.14

-.50

-.11

CaO

MgO

-0.57

-.83

-.74

-.61

.47

-.71

-.38

-.73

-.69

-.80

-.51

-.63

-.19

-.19

-.85

-.19

-.46

-.22

-.55

.40

MgO

KaO

0.72

.77

.51

.77

-.28

.48

.82

.32

.40

.69

.04

.29

.25

.49

.70

-.28

.04

.65

.73

-.46

-.68

KuO

NajO

0.37

.23

.09

.27

-.26

.13

.50

-.17

-.26

-.03

-.01

-.13

.01

.14

.06

-.09

.01

.56

-.18

-.49

.00

.20

Na2 0

Zn

0.39

.62

.58

.49

.06

.50

.05

.65

.83

.71

.46

.74

.34

.05

.65

.27

.52

-.05

.61

-.12

-.67

.37

-.37

Zn

Ct»

-0.64

-.66

-.47

-.59

.40

-.54

-.64

-.23

-.18

-.46

-.11

-.17

-.22

-.12

-.44

.04

-.14

-.71

-.19

.80

.48

-.62

-.77

-.06

C«

Cmln'

-0.61

-.74

-.77

-.59

.36

-.86

-.37

-.66

-.58

-.79

-.30

-.53

-.38

.18

-.65

-.24

-.35

-.45

-.33

.90

.71

-.63

-.33

-.42

.79

Cmln

CorgS

0.21

.35

.57

.14

.09

.55

-.27

.75

.71

.60

.30

.68

.31

-.32

.47

.47

.54

-.21

.37

-.15

-.49

.17

-.60

.64

.21

-.38

Cor.

Li

0.29

.58

.83

.41

-.20

.76

-.22

.84

.69

.75

.71

.73

.21

-.41

.58

.67

.78

-.14

.22

-.43

-.64

.16

-.07

.61

-.27

-.63

.63

Li

in the samples of Pennsylvanian black shade from Kansas and Oklahoma, and uranium, iron, cobalt, molybdenum, and nickel in the 

samples of Chattanooga Shale. Iron, present in pyrite, is apparently 

closely associated with the organic matter in the Chattanooga Shale. 

Where carbonate minerals are absent, calcium can also occur with 

organic matter, perhaps as a calcium humate or a similar organic 

compound, which explains its association in the Pennsylvanian black 

shale. The other differences between the organic-matter fractions of 

these two sets probably reflect differences in availability of the elements 

in the two environments.
G30 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 11. Element associations in set 8, 25 samples of black shale from the Paradox 

Member of the Hermosa Formation

[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* 

Y. Al. Ga, Fe, Cr, B, Cu, KaO. Zn. Li,

Ni, Ti, Si,

B, Ga, Fe, Al, Cr,

B, Ga, Fe, NaiO,

eU, La, Corg, Yb

V, Li, KaO, Si, Ti,

Cu, Ni, Zr

Zr, Al, 81, EaO, LI

Con, CaO

Y 

MgO

MgO, Cmln, CaO

Y

CaO, Cmln

MgO

Sr, Ba

MgO

MgO, Cmln, CaO

Cmln, MgO, CaO

MgO, Cmin 

MgO. Cmln

Cmln, CaO, MgO

Cmin, MgO, CaO

MgO, Cmin, CaO

MgO, Cmin, Cao

MgO, Cmln

MgO, Cmin

MgO

MgO, Cmin

NaaO, MgO

Element

Mn

MgO

Cmln

CaO

Pb

NaaO

Sr 

eU

KaO

Ba

Zr

La

Y

Yb 

Al

Si

Ti 

V

B

Fe

Ga

Li

Ni

Cr

Zn

Cu

Corg

 ^Positive correlation

MgO

Mn, Cmln

MgO, CaO

Cm ln

Ba,Zr

KsO,Ba 

Si, Fe, Ba, Ni, Al. Ti, Cu. Zn, V, Ga. KjO

B, Sr, Fe, Zr, Ga, V, Si, eU, Al, TI, Ba

V, eU, NaaO, Al, Ti, SI, Sr, Zr, KaO

Al, NaaO, KaO, Si, Ba

V, Zn, Ga, B. Fe. NI, Cr, Y, Yb, LI

Fe, Corg, B, Cr, Ni, Li, La, Yb

Si, Zn, V, Cor«, Ga, B. Al, Cu, La, Fe, Y, Cr, LI, Ni 

Zr, Ba, Li, eU, Yb. Zn, Cr. Cu. Ni, B. KaO, Fe, Ti, Ga.

Si, V

eU, Yb, Cu, Ni, B, Ga, Fe. Ti, Ba, KaO, Zr, V, Al

Ni, Cr, Cu, Zn. B. Ba. eU, Fe, Si, V, KaO, Ga, Al 

La, Ba, C(,,gt Yb, Li, eU, Zn. Cr. B, If, Cu, NI, KaO, SI,

Ga, Fe. Al

KaO, Y, La, Zn, Corg, TI, Si, Yb, V, Al, Cu, NI, LI, Ga,

Cr, Fe

Y, eU, KaO, La, Corg, Zn, TI, Si, Yb, Cu, Al, Ni, Li, V,

B, Cr, Ga

La, Yb, Corg, SI, eU, KaO, NI, Zn, LI, TI, Cr, Cu, Al, V,

Fe

Al. V, Zn, Corg, Y, Cu. La, NI, Ga, B, Yb, Fe, Cr

Ti, eU, Y, Si, La, Corg, Al, Ga, B, LI, V, Zn, Yb, Fe, Cr. 

Cu

TI, Y, La, Zn, Al, V, Yb, C0,g, Ga, Cu, B, LI, NI, Fe

La, Ti, B, Yb, Fe, Li, eU, Al, Corg, Cr, V, Ga, NI, Cu

Si, Ti. Yb, eU, Al, LI, Corg, V, B. Fe, Ga, Cr, Zn, NI

V, Y, Yb, B, Fe, Ga, LI, Zn, Ni, Cu, Cr

The elements associated with the organic-matter fraction in the 

Phosphoria and Paradox samples are not so clearly distinguished because of their relatively close association with the detrital-mineral 

fraction in both sets and with phosphate in the Phosphoria Formation. In contrast to the Paradox Formation, the abnormally high concentration of many minor elements in the Meade Peak Member of the 

Phosphoria Formation suggests that the upwelling cold, nutrient-rich 

water that was capable of supporting an abundance of living organisms and that provided a source for the phosphate may have also provided a renewable source of minor elements. The high concentration 

of such potentially toxic elements as selenium, molybdenum, and 

chromium seems to preclude the possibility of concentration as a part 

of the metabolic process of living organisms. As an alternative, the 

minor-element concentrations probably occurred while the organic 

matter after death and partial decay drifted to a final burial site.

Geochemical associations among the samples from the Paradox 

Member of the Hermosa Formation contrast sharply with those from 

the Phosphoria Formation. Although copper, zinc, and, to a lesser 

degree, several other minor elements show a tendency to correlate
ELEMENT DISTRIBUTION IN PALEOZOIC BLACK SHALES G31

with organic matter, none of these occurs in abnormally high concentration. Considering the volume of sea water that must have been 

concentrated by evaporation to produce the thousands of feet of saline 

minerals in the Paradox Basin, a question arises as to the fate of the 

associated minor elements, but the answer was not found within the 

scope of this study. The sparse organic matter in the Paradox samples 

is extremely fine grained; yet perhaps it was not sufficiently decayed 

prior to burial to produce optimum conditions for minor-element 

absorption.

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U. S. GOVERNMENT PRINTING OFFICE : 1969 O - 329-581