U.S. GEOLOGICAL SURVEY CIRCULAR 1058 

Metalliferous Black Shales and 

Related Ore DepositsProceedings, 1989 United States 

Working Group Meeting, 

International Geological Correlation 

Program Project 2 54 
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Metalliferous Black Shales and 

Related Ore DepositsProceedings, 1989 United States 

Working Group Meeting, 

International Geological Correlation 

Program Project 2 54 
Frontispiece: Nickel-copper-zinc-mineralized, Proterozoic (1 .96-2.00 Ga) black shales, Talvivaara prospect, Finland. 

Photograph by Kirsti Loukola-Ruskeeniemi, Geological Survey of Finland. 
Metalliferous Black Shales and 

Related Ore DepositsProceedings, 1989 United States 

Working Group Meeting, 

International Geological Correlation 

Program Project 2 54 

Edited by RICHARD I. GRAUCH and HOLLY L.O. HUYCK 

U.S. GEOLOGICAL SURVEY CIRCULAR 1058 
U.S. DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, JR., Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Any use of trade, product, or firm names in this publication is for descriptive 

purposes only and does not imply endorsement by the U.S. Government. 

Organizing committee for the 1989 meeting of the International Geological 

Correlation Program-Project 254 United States Working Group, Holly L.O. 

Huyck, Chairwoman 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1990 

Free on application to 

Books and Open-File Reports Section 

U.S. Geological Survey 

Federal Center 

Box 25425 

Denver, CO 80225 

Library of Congress Cataloging-in-Publication Data 

Metalliferous black shales and related ore deposits-Proceedings, ; 1989 United 

States Working Group meeting, International Geological Correlation Program 

Project 254 I edited by Richard I. Grauch and Holly L.O. Huyck. 

p. cm.-(U.S. Geological Survey circular : 1 058) 

Includes bibliographical references. 

Supt. of Docs. no.: I 19.4/2:1085. 

1. Shale-Congresses. 2. Ore deposits-Congresses. I. Grauch, Richard I. 

II. Huyck, Holly L.O. Ill. International Geological Correlation Programme. 

Project 254. United States Working Group. IV. Series. 

TN948.S5M48 1991 90-20610 

553.2'83-<lc20 CIP 
FOREVv'ORD 

Richard I. Grauch, Leader, U.S. Working Group, 

International Geological Corr,elation Program Project 254 

Vice-Leader, International Geological Correlation Program Project 254 

The papers and extended abstracts of this circular are summaries of most of the 

papers presented at the November 4, 1989, meeting of the U.S. Working Group of the 

International Geological Correlation Program's Project 254, Metalliferous Black Shales 

and Related Ore Deposits. 

The International Geological Correlation Program (IGCP) has two principal 

objectives. The "primary goal is to encourage and facilitate geological research on a global 

scale, and to foster international cooperation. Current research stresses the nature and 

timing of major geologic events, the distribution and genesis of mineral and energy 

resources, and geological hazards" (B.J. Ski111ner and C.L. Drake, 1987, An unacclaimed 

success story: Geotimes, v. 32, no. 4, p. 11 ). "A secondary objective of many IGCP 

projects is to improve the geological capabiHty and knowledge in developing countries" 

(U.S. National Committee for International Geological Correlation Program, 1988, The 

International Geological Correlation Program, Newsletter 8, p. i). The IGCP is a joint 

functionary of the International Union of Geological Sciences (lUGS) and the United 

Nations Educational, Scientific, and Cultural Organization (UNESCO). It is guided by an 

advisory scientific committee and by a 15-member board of scientists who are jointly 

appointed by lUGS and UNESCO. Most of the 90 participating nations have appointed 

national committees to coordinate the activilties of the various national working groups 

that are associated with individual IGCP projects. 

IGCP Project 254 was initiated by Jan Pasava of the Geological Survey, Prague, 

Czechoslovakia. Its primary, very ambitious, goals are (1) to compile and correlate data 

regarding metalliferous black-shale formations and related ore deposits, (2) to evaluate the 

role of depositional, diagenetic, volcanic, magmatic, metamorphic, and tectonic processes 

in the origin of metalliferous black shales and related ore deposits, (3) to investigate the 

roles of organic matter and sulfide in mineralization processes, and ( 4) to develop 

exploration criteria for ore deposits in black--shale formations. 

The leadership of the project is as follows: 

Leader: 

Vice-Leaders: 

Secretary: 

Treasurer: 

Executive Board: 

J. Pasava, Czechoslovakia 

R.I. Grauch, U.S.A. 

V.A. Buryak, U.S.S.R. 

B.Buc~ardt, Denmark 

Z. Gabriel, Czechoslovakia 

I.R. Plimer, Australia 

I.R. Jonasson, Canada 

B. Kribek, Czechoslovakila 

M. Pulec, Czechoslovakia 

K. Ruskeeniemi, Finland 

M. Pagel, France 

B. Stribrny, Federal Republic of Germany 

H. Dill, Federal Republic of Germany 

R.C. Mehrotra, India 

F. El Salem, Jordan 

Foreword V 
A. Tijani, Morocco 

M. Banas, Poland 

L. Moshen, Tunis 

V. Petrov, U.S.S.R. 

S. Rodriguez, Venezuela 

N. Shaffer, U.S.A. 

Fan Delian, People's Republic of China 

At the international level the project is divided into eight working groups: (1) Au and Ag 

mineralizations, (2) platinum-group element and Cr mineralizations, (3) U, Mo, and V 

mineralizations, (4) Pb, Zn, Cu, and barite mineralizations, (5) Cu mineralizations, (6) Sn, 

W, Hg, and Sb mineralizations, (7) Mn and Fe mineralizations, and (8) international 

standards and correlation of analytical measurements. Additionally, most of the 25 

participating nations have formed multidisciplinary national working groups that have 

their own leaders and are expected to meet annually. These national working groups are 

generally loosely structured, and the individual participants are probably more closely 

aligned with the topical international working groups described above. 

The diverse interests of the approximately 70 members (listed near the end of this 

circular) of the U.S. working group are well represented by the wide-ranging research 

topics presented at this meeting. We are excited about this new forum for communication 

and the synergism gained through international, multidisciplinary contacts. In addition, we 

have the ability (funded through the U.S. National Committee for IGCP) to assist in 

defraying the travel expenses of members who attend international project meetings and 

student members who attend national meetings. The meetings are open to all interested 

parties and the working group welcomes new members. 

We thank the U.S. Geological Survey for publishing this circular. 

International Meetings of International Geological Correlation Program Project 254 

October, 1987 

July, 1988 

July, 1989 

August, 1990 

November, 1990 

August, 1991 

VI Foreword 

Jesenik, Czechoslovakia. Inaugural meeting. 

Beijing, China. First international working session (in conjunction 

with the International Symposium on Sedimentalogy Related to Ore 

Deposits). 

Washington, U.S.A. Second international working session (in 

conjunction with the International Geological Congress, Symposium 

C25). 

Ottawa, Canada. Third international working session (in conjunction 

with the International Association on the Genesis of Ore Deposits 

Symposium). 

Rabat, Morocco. International workshop and field conference 

(cosponsored by the Geological Society of Morocco). 

Novosibirsk, U.S.S.R. International workshop and field conference, 

"Black shale basins and related mineral deposits" (cosponsored by 

the Siberian Branch of the Academy of Sciences of the U.S.S.R.). 
CONTENTS 

Geochemistry of the Ordovician high-calcium black shales hosting major gold deposits 

of the Getchell trend in Nevada, by E.l. Hloomstein and J.B. Clark 1 

Geochemical control on the abundance of vanadium in black shales and related rocks, 

by George N. Breit, Richard B. Wanty, and Michele L. Tuttle 6 

Nickel-molybdenum-platinum-gold deposits in black shales of southern China-A new 

ore type with possible analogs in Pennsylvanian rocks of the U.S.A., 

by Raymond M. Coveney, Jr., and Chen :~ansheng 9 

Geochemical and mineralogical comparison of the upper Pennsylvanian Stark Shale 

Member of the Dennis Limestone, east-central Kansas, with the Middle 

Pennsylvanian Mecca Quarry Shale Member of the Carbondale Formation in Illinois 

and of the Linton Formation in Indiana, by G.A. Desborough, J.R. Hatch, and 

J.S. Leventhal 12 

Organic ligands and metal-organic complexing in ore fluids of sedimentary origin, 

by Thomas H. Giordano 31 

When is a metalliferous black shale not a black shale?, by Holly L.O. Huyck 42 

Recent Black Sea sediments-Leg 4, 1988 Black Sea Expedition, 

by Timothy W. Lyons 57 

Organic geochemical studies of metalliferous parts of the Middle Proterozoic Nonesuch 

Formation of northern Michigan, by Philip A. Meyers, Eileen S. Ho, and 

Jeffrey L. Mauk 59 

Organic geochemical and petrological investigations of a natural reactor and its 

environs at Oklo, Gabon-A preliminary report, by Bartholomew Nagy, 

Joel S. Leventhal, and F. Gauthier-Lafaye: 65 

Midcontinent Virgilian (Upper Pennsylvanian) black shales in eastern Kansas, 

by R.B. Schultz and J.B. Maynard 68 

Membership of the U.S. Working Group of the International Geological Correlation 

Program Project 254 79 

Author index 85 

Contents VII 

METALLIFEROUS BLACK SHALES AND RELATED ORE DEPOSITSPROCEEDINGS, 1989 UNITED STATES WORKING GROUP MEETING, 

INTERNATIONAL GEOLOGICAL CORRELATION PROGRAM PROJECT 254 

Geochemistry of the Ordovi<:ian High-Calcium 

Black Shales Hosting Major ~cold Deposits of the 

Getchell Trend in Nevada 

By E. I. Bloomstein 1 and J.B. Clark 1 

Deep-water marine black shales (generally metamorphosed to greenschist facies) host significant gold deposits worldwide, among them Bendigo in Australia, Muruntau and Sukhoi Log in the U.S.S.R., and Sucha Rudna in 

Czechoslovakia. In the Nevada gold province, auriferous 

Paleozoic black shales are part of a carbonate turbidite assemblage consisting of silty carbonaceous limestone and 

dolomite. Unfortunately, the black shales have not been 

identified as a separate unit within this assemblage. We 

believe that several gold deposits in the Osgood Mountains and other areas are associated with black shales. In 

particular, Ordovician black shales of the Comus Formation and carbonaceous phyllite of the Cambrian Preble 

Formation are hosts for the Getchell Trend gold deposits, 

namely Rabbit Creek, Getchell, and Pinson (fig. 1 ). Another example of a mineralized black shale is the Pilot 

Shale of Mississippian and Devonian age, which hosts the 

Alligator Ridge gold deposit (Ilchik and Brimhall, 1986). 

On the other hand, the black shales of the Devonian 

Woodruff Formation in north-central Nevada are not 

known to host gold deposits. The geochemical and mineralogical properties of black shales that make them favorable hosts for gold mineralization are still poorly understood. 

Our presentation concerns the black shales and dolomite mudstones of the Comus Formation. In the area of 

the Rabbit Creek gold deposit (Bloomstein and others, in 

Manuscript approved for publication, October 9, 1990. 

1

Santa Fe Pacific Mining Corporation, Box 27109, Albuquerque, 

New Mexico, 87125-7019. 

press), the shales are 150-250 m thick. Based upon rhythmic bedding, graded beds, and characteristic conodont 

fauna, they are interpreted to be quiescent deep--water 

shales deposited in an anoxic environment. The shahs are 

directly overlain by sparsely vesicular basalt flows believed to have formed at seawater depths between 500 

and 1,800 m. 

The unoxidized shales and mudstones consist of 

about 20 percent illite, 20 percent carbonate minerr ls (as 

aggregates and intraclasts of calcite and rhombo'ledral 

grains of dolomite), 4~5 percent detrital quart~. and 

12-15 percent syngenetic pyrite as amorphous grains, 

framboids, and cubes. The organic carbon content of the 

shales of the Comus is generally 1-1.5 percent but may 

be as high as 5 percent. Organic matter is type I or II 

kerogen, marine algal in origin, as evidenced by large 

amounts of tricyclic terpane biomarkers and by hig'l proportions of C27 and C28 sterane (Philp, 1985). M ~st of 

the organic carbon is overmature, having the nmk of 

meta-anthracite; extractable bitumen in amounts c.f 30-

80 ppm is also present. Gas chromatography results show 

that the bitumen consists of short-chain and long-crain nalkanes. The presence of such immature material rrquires 

that bitumen migrated into the shales after the kerogen 

had thermally matured. All organic matter was introduced 

before the gold mineralization took place. 

The shales of the Comus (table 1) are calc"reous 

(11.35 weight percent CaO) and locally dolomitic (3.71 

weight percent MgO). True limestones are not p""esent. 

The TiO~Al 3 ratio (0.087) may indicate a slight mafic 

volcanic input into the clastic material (Spears and 

Kanaris-Sotirou, 1976). 

Ordovician High-Calcium Black Shal""~ 1 
NEVADA 

(/ 

EXPLANATION 

~ COMUS FORMATION 

D PREBLE FORMATION 

Winnemucca 

0 

Sonoma Range 

0 

0 

0 

~RABBIT 

CREEK 

10 MILES 

10 KILOMETERS 

Figure 1. Location map of Comus and Preble Formation and associated gold mines in north-central Nevada. 

Unmineralized samples of shales of the Comus were 

carefully selected to characterize the background geochemistry, but, because they are in close proximity to 

gold deposits, they may reflect a district-scale halo of 

mineralization. The shales of the Comus are enriched in 

As, Sb, Hg, and Ag (table 2), having abundances at least 

twice those of USGS Standard SD0-1. 

Hydrothermal alteration of the Comus black shales 

at Rabbit Creek consists of decalcification and later silicification and dolomitization. These processes are illus2 Metalliferous Black Shales and Related Ore Deposits 

trated on addition/depletion diagrams (figs. 2 a'ld 3). Gold 

mineralization is associated with significant enrichment of 

As, Sb, and Hg and minor enrichment of Ba, Cu, Zn, and 

v (fig. 3). 

The Pilot Shale has about the same amount and type 

of organic carbon (1-3 weight percent, marine) as the 

shales of the Comus, but the shales of the Wo')druff have 

significantly more organic carbon (15 weight r~rcent) that 

has a continental source (Dean and others, 1987). The 

shales of the Pilot and Woodruff are as calcar~~ous and as 
0 

a. 

~ ;::;· 

~· 

:::E: 

aa· 

:r 

h 

!.. 

n 

E' 

3 

i» = 

n 

:II:" 

fll 

:r 

1»_. 

~ 

w 

Table 1. Average chemical composition of unoxidized, unmineralized black shales of north-central Nevada 

[In weight percent] 

Associated Number of 

Unit gold deposit Si02 Al2o3 CaO MgO FeO Na2o K20 Ti02 Ti/AI analyses 

Comus Formation .......... Rabbit Creek ......... 52.26 9.11 11.35 3.71 4.82 0.30 1.83 0.79 0.087 110 

Pilot Shale ................... Alligator Ridge ...... 53.50 4.32 5.67 3.82 2.35 0.17 1.58 0.24 0.056 3 

Woodruff Formation ....... None ................... N/ A* 6.55 13.02 7.00 1.77 0.17 2.07 0.26 0.040 4 

* Not analyzed. 

Table 2. Average trace element content of unoxidized, unmineralized black shales of north-central Nevada 

[In parts per million. N/A indicates not analyzed] 

Formation Ba Sr As 

Comus Formation .......... .4 7 128 231 

Pilot Shale .................. 330 328 330 

Woodruff Formation ...... 833 290 80 

USGS StandardS00-1 ... 397 75 69 

Metalliferous Black 

Shale** ................. 1,000 1,500 137 

*Number of analyses varies depending on the element. 

**Huyck (1990, written commun.). 

Sb 

9 

9 

45 

4 

9 

Number of 

Hg Cu Pb Zn Mo V Ni Co Ag Th U analyses 

2, 774 25 7 48 2 14 13 8 0.36 3 6 28 

453 30 12 149 5 67 74 13 0.27 6 2 3 

N/A 141 12 1,337 84 3,148 285 4 2.25 5 N/A 4 

2 60 28 64 134 160 100 47 0.13 10 49 1-26* 

4 120 56 128 134 320 199 47 0.26 21 49 
1-

z 

UJ 

() 

a: 

UJ 

a.. 

1-

J: 

(.!) 

w 

~ 

~ ADDITION 

6 

UJ 

1-

UJ 

...J 

a.. 

UJ 

0 

a: 

0 

0 

UJ 

0 

0 

<( 

1-

z 

:::;) 

0 DEPLETION ::?! 

<( 

Figure 2. Geochemical addition and depletion associated with gold mineralization in the Comus Formation. 

dolomitic as the shale of the Comus (table 1 ). Relative to 

the Comus, the source rocks for shales of the Pilot and 

Woodruff are apparently nonvolcanic and have lower 

Ti02/Al20 3 ratios (0.056 and 0.040, respectively). Similar 

to the Comus, the Pilot Shale is enriched in As, Sb, Hg, 

Ag, Sr, and Zn relative to standard SD0-1. In contrast, 

the shales of the Woodruff are highly organic-rich black 

shales that have high contents of such trace elements as 

V, Ni, Zn, Cu, Ag, Sr, and Ba (table 2). Their composition is similar to that suggested as the standard for defining "metalliferous black shales" (H.L.O. Huyck, 1990, 

written commun.). 

Geochemical features make Paleozoic black shales 

such as the Comus and Pilot favorable host rocks for 

Oligocene-Miocene gold mineralization: (1) relatively significant amounts of CaO (5-13 weight percent) and MgO 

(3-7 weight percent) allow decalcification and result in 

increased permeability; (2) relatively low organic carbon 

content (1-5 percent) promotes permeability; organic carbon content of more than 10 percent probably inhibits 

permeability; and (3) strong thermal maturation of organic 

carbon may provide high sorption capacity for precipitating gold from hydrothermal solution. 

4 Metalliferous Black Shales and Related Ore Deposits 

REFERENCES CITED 

Bloomstein, E.l., Massingill, G.L., Parratt, R.L., and Peltonen, 

D.R., 1991, Discovery, geology and mineralization of the 

Rabbit Creek Gold deposit, Humboldt County, Nevada, in 

Geology and ore deposits of the Great Basin: Geological 

Society of Nevada, Reno, Symposium Proceedings, v. 2, 

p. 821-844. 

Dean, W.E., Pratt, L.M., Briggs, T.A., Daws, T.A., Engleman, 

E.E., Jackson, L.L., Layman, L.R., Ryder, J.L., Stone, C.L., 

Threlkeld, C.N., and Vuletich, A.K., 1987, Data on geochemistry of Carlin-type disseminated golc"l deposits and 

associated rocks, north-central Nevada: U.S. Geological 

Survey Open-File Report 87-4466, 22 p. 

Ilchik, R.P., and Brimhall, G.H., 1986, Hydrothemal maturation 

of indigenous organic matter at the Alligat-:-r Ridge gold 

deposits, Nevada: Economic Geology, v. 81, p. 113-130. 

Philp, R.P., 1985, Fossil fuel biomarker, application and spectra: 

Amsterdam, Elsevier, 294 p. 

Spears, D.A., and Kanaris-Sotirou, R., 1976, Tita,ium in some 

carboniferous sediments from Great Britain: Geochimica et 

Cosmochemica Acta, v. 40, p. 345-351. 
As 4,739 ppm As 

z 

0 ADDITION ::::; 

....J 

~ 

a: 

UJ 

a.. 

C/) Zn 

1-

a: 

~ Ba 

~ 

ci 

UJ 

1-

UJ 

....J 

a.. 

UJ v 

Cl 

a: Au 

0 

Cl 

UJ 

Cl 

Cl 

<( 

1-

z 

=> 

0 

~ DEPLETION <( 

Figure 3. Trace-element addition and depletion associated with gold mineralization in the Comus Formation. 

Ordovician High-Calcium Black Shale~ 5 
Geochemical Control on the Abundance of Vanadium in 

Black Shales and Other Carbonaceous Rocks 

By George N. Breit1

, Richard B. Wanty1

, and Michele L. Tuttle1 

High concentrations of vanadium (>500 ppm) in 

black shales and other carbonaceous rocks can be explained by processes active at their time of deposition. 

Attributes common to most of these vanadiferous rocks 

include ( 1) strong vanadium-organic carbon correlations, 

(2) proximity to rocks enriched in phosphate, (3) high 

contents of organically bound sulfur, and (4) relatively 

slow rates of deposition in marine basins. Chemical conditions in the sediment and water column likely to produce these attributes were considered together with the 

general geochemical characteristics of vanadium to identify conditions favoring vanadium accumulation. The geochemistry of vanadium was evaluated by combining existing thermodynamic data for dissolved vanadium species 

and results of experimental studies of vanadium adsorption and reduction (Wanty, 1986; Breit and Wanty, unpublished data). 

Reduction/oxidation, adsorption, and complexation 

control the mobility and accumulation of vanadium 

(fig. 1). Vanadate species (V(V)), the dominant species in 

aerated surface waters, adsorbs strongly to some mineral 

surfaces, particularly ferric oxides, and limits the concentration of dissolved vanadium in waters of moderate pH. 

Adsorption to biogenic particles such as fecal pellets contributes to the depletion of dissolved vanadium in 

shallow-marine waters and the addition of vanadium to 

sediments (Collier, 1984). In oxic waters, most vanadium 

will eventually redissolve during remineralization of the 

settling particles. In shallow oxic or deeper anoxic waters, 

the association of detrital organic matter and vanadium is 

more likely to be preserved. The amount of adsorbed 

vanadium may further increase in anoxic waters because 

of the reduction of vanadate (V(V)) to vanadyl (V(IV)), 

which has a greater tendency to adsorb. Nat ural reductants capable of reducing V(V) include dissolved organic 

compounds and H2S, or organic constituents on the surface of settling particles. Formation of stable organic 

1

U.S. Geological Survey, Denver Federal Center, Box 25046, 

MS 916, Denver, Colorado 80225. 

6 Metalliferous Black Shales and Related Ore Deposits 

complexes by the vanadyl ion relative to ma"ly transition 

metals explains why vanadium and organic carbon are 

well correlated (r >0.8) in many carbonaceous units. The 

reported high abundances of vanadyl-organi~ species in 

petroleum attests to the particular stability o:f these complexes (Lewan and Maynard, 1982). Diffusion of vanadium across the sediment-water interface may also increase the concentration of vanadium in sediment. This 

process is driven by the reduction, complexation, and adsorption of vanadium. Calculations using apparent concentration gradients (Brumsack, 1986) to estimate rates of 

diffusion suggest that this process is signifi,~ant only in 

very slowly accumulating sediments (<0.01 mm/yr). 

Vanadium-rich carbonaceous rocks co'llmonly are 

interbedded with and transitional to rocks enriched in 

phosphate. The separation of vanadium-rich carbonaceous 

and phosphatic rocks in two units is the resul~ of the contrasting composition of depositional waters. Phosphate accumulations form when organic matter is partly destroyed 

under suboxic conditions, whereas carbonaceous matter 

and associated vanadium are mostly retained by sediments 

that are in contact with anoxic or euxinic wat~'!rs. 

The presence of organically bound sulfur in 

vanadium-rich petroleum and in some vanadium-rich carbonaceous rocks suggests that H2S was abundant during 

early diagenesis of vanadium-rich carbonace0' 1S sediments 

(Baker and Louda, 1986; Patterson and others, 1986). 

H2S not consumed in pyrite formation reac·~d with organic matter or diffused upward, possibly resulting in 

euxinic bottom waters. Under natural conditicns only H2S 

is known to reduce V(IV) to V(III), an oxidation state 

that favors incorporation of vanadium into clay minerals. 

The abundance of vanadiferous clays that contain V(III) 

in several oil shales and black shales indicztes that this 

process is active during diagenesis of carbonaceous sediments. Vanadium partitioned into clays may be retained 

during metamorphism to produce vanadium-rich mica in 

graphitic schist. In chemical or biogenic sedinents having 

high organic carbon to clay ratios, vanadium remains 

complexed with organic matter and may eventually migrate as a component of petroleum. 
~ V (V) 

~ 

Vanadium concentration 

Increasing ... 

Water 

a: 

w 

1-

c( 

0 percent adsorbed 

--------------------------------- 3: 

adsorption to settling particles 

-----~ ~0;+-H~s----;~;;;z+---t---- ~~ vo2+ + H

2

S ___. V(OH) 3? 

1-

z 

w 

== c 

w 

en 

Vo2+ . - orgamc complexes; V (Ill)- clays 

+ Discrete porphyrins (50- 150°C ?) 

in migrating oil ~ 1 Loss of V 

Vanadium-rich clays 

Vanadium-rich ~ micas ( -200°C) 

Sediment 

0 

'I 

..J 

<( 

~1 <( 

w 

a: 

() 

z 

1 wt. percent 

Figure 1. Geochemical processes that affect the abundance and speciation of dissolved vanadium and the distributior of 

vanadium in sediments during diagenesis. Vanadium concentration profiles are estimated based on the geochemiral 

processes. Concentrations in water are nanomolar; concentrations in sediment are weight percent on a dry-weight basis. 

The content of vanadium is higher in marine carbonaceous rocks as compared to rocks deposited in lacustrine environments because of the greater amount of vanadium made available by circulating seawater. Massbalance calculations based on modem analogs restrict the 

abundance of vanadium in lacustrine sediments to less 

than 200 ppm even if the Eh, abundance of organic carbon, and H2S activity are comparable to those in euxinic 

marine basins. Similar calculations for a stratified marine 

basin require that the basin be open to seawater circulation. Open circulation is necessary to supply sufficient 

vanadium to result in carbonaceous sedimentary rocks 

having vanadium contents exceeding 500 ppm. 

REFERENCES CITED 

Baker, E.W., and Louda, J.W., 1986, Porphyrins in the geo1ogical 

record, in Johns, R.B., ed., Biological markers in the 

sedimentary record-Methods in geochemistry and geophysics 24: New York, Elsevier, p. 126-225. 

Brumsack, H.J., 1986, The inorganic geochemistry of Cret.,~eous 

black shales (DSDP Leg 41) in comparison to modern 

upwelling sediments from the Gulf of Califorria, in 

Summerhayes, C.P., and Shackleton, N.J., eds., North 

Atlantic paleoceanography: Geological Society of London 

Special Publication 21, p. 447-462. 

Collier, R.W., 1984, Particulate and dissolved vanadium in the 

North Pacific Ocean: Nature, v. 309, p. 441--444. 

Vanadium in Black ShalE'"- 7 
Lewan, M.D., and Maynard, J.B., 1982, Factors controlling 

enrichment of vanadium and nickel in the bitumen of 

organic sedimentary rocks: Geochimica et Cosmochimica 

Acta, v. 46, p. 2547-2560. 

Patterson, J.H., Ramsden, A.R., Dale, L.S., and Pardy, J.J., 1986, 

Geochemistry and mineralogical residences of trace 

8 Metalliferous Black Shales and Related Ore Deposits 

elements in oil shales from Julia Creek, Queensland, 

Australia: Chemical Geology, v. 55, p. 1-16. 

Wanty, R.B., 1986, Geochemistry of vanadium in an epigenetic 

sandstone-hosted vanadium-uranium deposit, Henry basin, 

Utah: Golden, Colorado School of Mines, Ph.D. thesis, 

198 p. 
Nickel-Molybdenum-Platinum-Gold Deposits 

in Black Shales of Southern ChinaA New Ore Type with Possible Analogs in 

Pennsylvanian Rocks of the U.S.A. 

By Raymond M. Coveney, Jr., 1 and Chen Nansheng2 

Since 1985, deposits near Song lin, Zunyi County, 

Guizhou Province, in the People's Republic of China 

have been mined for molybdenum. Thin nodular sulfide 

lenses in a 2-m-thick horizon of black shale just above 

the Proterozoic-Cambrian boundary contain 2-7 percent 

Mo and as much as 4 percent Ni, 2 percent Zn, 0.7 ppm 

Au, 50 ppm Ag, 0.3 ppm Pt, and 30 ppb Ir (Chen and 

others, 1982; Fan, 1983; Fan and others, 1984; Chen, 

1988; Chen and Coveney, 1988; Coveney and Chen, 

1989). Our analyses indicate the presence of 1-2.5 percent As and as much as 2, 700 ppm Se. The Zunyi Mo 

mines currently produce about 1,000 tons of molybdenum 

ore per year and are the only mines in the world where 

molybdenum is recovered from shale. Precious metals are 

not recovered from the ores, but mill tailings are being 

stockpiled for their future recovery. 

Metal-rich Cambrian black shales are in nine other 

provinces in southern China (Chen and others, 1982). For 

example, about 350 km east of Zunyi (fig. 1 ), Cambrian 

shales near Dayong, Hunan, contain similar nodular nickelmolybdenum sulfide lenses enriched in platinum-group 

elements (Fan, 1983). Other nickel-molybdenum deposits 

are in Cambrian shales near Dezhe, Yunnan (Chen and 

others, 1982), and in metamorphosed Lower Cambrian 

beds near Lizhe, Zhejiang (Chen and Yang, 1987). None 

of these deposits has any obvious connection with ultramafic source rocks, although ophiolites are present in the 

general region (fig. 1 ). 

Nodular textures (Fan, 1983), the presence of siliceous venting tubes, and other features imply that hydrothermal submarine springs related to basement faults de1

Department of Geosciences, University of Missouri-Kansas City, 

Kansas City, Missouri 64110. 2Institute of Geochemistry, Academia Sinica, Guiyang. Guizhou 

Province, People's Republic of China. 

posited metals during sedimentation (Chen, 1988); however, in some cases a nonsyngenetic component to the 

mineralization may be significant. Results of five measurements of sulfur isotope deviations (o34S) for samples 

drilled from pyrite nodules from Zunyi and Dayong are 

from -11.2 to -7.3 per mil relative to the Canon Diablo 

troilite standard and average -9.94 per mil. Rims of 

porous (and possibly corroded) pyrite are on some sulfide 

nodules. Analysis of the rim of one such nodule from 

Zunyi yielded a o34S value of +3.7 per mil in contrast 

with -10.2 per mil for the interior. Energy-difnersive 

scanning electron microscopy of this pyrite nodule and 

others indicates that late pyrite rims contain more Ni, Mo, 

As, and Se than the interiors. Lyons (1989) has di~cussed 

somewhat analogous isotopic variations in a bed of iron 

sulfide from the Devonian of New York. One of the possible interpretations that he infers for subtly enriched 

values for o34S on the fringes of nodules is progressive 

enrichment of heavy sulfur resulting from a closed system. This process may also be operative in the cas~~ of the 

Chinese deposits, but the striking compositional changes 

between the interior and rim of at least one sulfide nodule 

suggest the possibility of two stages of mineralization. 

The first stage is likely hydrothermal and syngene+ic. The 

second stage may be a supergene event related to the 

modern regional karstification that is spectacularly well 

developed in southern China. The second stage of mineralization may also be related to ancient weathering. For 

example, the deposits may be analogous to uncorformity 

uranium deposits, which are related to deep ancient 

weathering events and which also can have e-nriched 

platinum-group-element values (Grauch, 1989). 

The Chinese deposits were first discovered during 

the 1970's, and similar deposits may have bee, overlooked elsewhere in the world. High platinum values are 

known from shales in Poland (Kucha, 1982), and sulfide 

Nickel-Molybdenum-Platinum-Gold Deposits in Black Shales 9 
NEI MONGGOL 

QINGHAI 

SICHUAN 

YUNNAN 

Soutll Ch•n• S•• 

0 500km •. _.._ .......... _ ... _.,. 

Figure 1. Nickel-molybdenum-platinum-gold deposits (solid squares) hosted by Cambrian black shales in southern China. 

Nickel-molybdenum sulfide lenses or layers are found at Dezhe, Zhijin, Zunyi, Cili, Dayong, Duchang, and lizhe. Ophiolites 

(shown as irregular black areas) are exaggerated in size for clarity; locations are from Hsu and others (1988). 

deposits resembling the Chinese deposits have recently 

been discovered in Canada (L. Hulbert, Canadian Geological Survey, oral commun., 1988). In addition, extensive 

molybdenum-rich shales in the Pennsylvanian of the central U.S. (Coveney and Martin, 1983) may have ore-grade 

enrichments associated with basement structures such as 

the Humboldt fault of Kansas and the Reelfoot rift zone 

of illinois. Orth and others (1988) found whole-rock values for platinum as high as 160 ppb in Carboniferous 

beds of Oklahoma not far from the extension of the Humboldt fault. Distal to this major basement structure in 

Linn County, Kansas, and Platte County, Missouri, what 

may be minor expulsion vents have been observed in 

limestones associated with metal-rich Pennsylvanian 

1 0 Metalliferous Black Shales and Related Ore Deposits 

shales in the form of mineralized animal burr'lws or root 

casts containing ferroan dolomite, with or wi•hout petroleum, hydrothermal quartz, calcite, barite, O'" sphalerite 

(Coveney, 1991). 

The recently discovered nickel-molybdenum-platinum-gold deposits of China and related deposits associated with black shales may constitute a resource of global 

significance for nickel, molybdenum, and platinum-group 

metals. The presence of a major molybdenum anomaly in 

Pennsylvanian beds comparable to that in Chinese Cambrian shales and the high platinum-group-element values 

in the Carboniferous rocks of Oklahoma sugr~st that regional exploration for similar deposits may b~ warranted 

in the U.S.A. 
REFERENCES CITED 

Chen Nansheng, 1988, The Cambrian hydrothermal sedimentary 

molybdenum and nickel ore deposits in south China: 

International Association of Sedimentologists, International 

Symposium on Sedimentology Related to Mineral Deposits, 

Beijing, Abstracts, p. 29. 

Chen Nansheng, and Coveney, R.M., 1988, Ores in metal-rich 

shales of China [abs.]: U.S. Geological Survey Circular 

1037' p. 7-8. 

Chen Nansheng, and Yang Xiuzhen, 1987, Studies of Lizhe 

molybdenum ore deposit of sedimentary-magmatic hydropneumatic origin, Lizhe, Zhejiang province (in Chinese): 

Geochimica, v. 9, p. 208-214. 

Chen Nansheng, Yang Xiuzhen, Liu Dehan, Xiao Xuejun, Fan 

Delian, and Wang, Lianfang, 1982, Lower Cambrian black 

argillaceous and arenaceous rock series in south China and 

its associated stratiform deposits (in Chinese): Mineral 

Deposits, v. 1, p. 39-51. 

Coveney, R.M., Jr., 1991, Evidence for expulsion of hydrothermal 

fluids and hydrocarbons in the Midcontinent during the 

Pennsylvanian, in Proceedings of a Workshop on Source 

Rocks, Generation, and Migration of Hydrocarbons and 

Other Fluids in the Southern Midcontinent: Oklahoma 

Geological Survey Circular 93. 

Coveney, R.M., Jr., and Chen Nansheng, 1989, Nickel and 

molybdenum-rich shales of southern China-A new ore 

type with possible analogues in the Pennsylvania of the 

USA: International Geological Congress, 28th, Washington, 

D.C., Abstracts v. 1, p. I335-1336. 

Coveney, R.M., Jr., and Martin, S.P., 1983, Molybdenum and 

other heavy metals of the Mecca Quarry and Logan Quarry 

shales: Economic Geology v. 78, p. 132-149. 

Fan Delian, 1983, Polyelements in the Lower Cambriar black 

shale series in southern China, in Augustithis, S.S., e1., The 

significance of trace metals in solving petro-;:enetic 

problems and controversies: Athens, Theophrastus Publications S.A., p. 447-474. 

Fan Delian, Yang Ruiying, and Huang Zhongxiang, 198 4, The 

Lower Cambrian black shale series and iridium anomaly in 

south China, in Developments in geoscience, Contri';utions 

to the 27th Geological Congress, 1984: Beijing, Moscow 

Academia Sinica, Beijing, p. 215-224. 

Grauch, R.I., 1989, Early-Middle Proterozoic unconfonritiesSources for platinum group and precious metals: U.S. 

Geological Survey Circular 1035, p. 26. 

Hsu, K.J., Sun Shu, Chen Haihong, Pen Haipo, and Sengor, 

A.M.C., 1988, Mesozoic overthrusts in south China: 

Geology, v. 16, p. 418-421. 

Kucha, H., 1982, Platinum group metals in the Zechstein copper 

deposits, Poland: Economic Geology, v. 77, p. 1578 -1591. 

Lyons, T.W., 1989, A sulfur isotope study of the Leicester Pyrite 

Member (Middle Devonian) of western New York 

State-Preliminary results: U.S. Geological Survey Circular 

1037' p. 2-4. 

Orth, C.J., Quintana, L.R., Gilmore, J.S., Barrick, J.E., Haywa, 

J.N., and Spesshardt, S.A., 1988, Pt-group anomalie8 in the 

lower Mississippian of southern Oklahoma: Geology, v. 16, 

p. 627-630. 

Nickel-Molybdenum-Platinum-Gold Deposits in Black Shale~ 11 
Geochemical and Mineralogical Comparison of the 

Upper Pennsylvanian Stark Shale Member of the Dennis 

Limestone, East-Central Kansas, with the Middle 

Pennsylvanian Mecca Quarry Shale Member 

of the Carbondale Formation in Illinois and of the 

Linton Formation in Indiana 

By G.A. Desborough 1, j.R. Hatch2, and J.S. Leventhal 3 

Abstract 

A geochemical and mineralogical study of the Middle 

Pennsylvanian Mecca Quarry Shale Member of the Linton 

Formation in Indiana and of the Carbondale Formation in 

Illinois and the Upper Pennsylvanian Stark Shale Member of 

the Dennis Limestone in east-central Kansas was done to 

compare and contrast the compositions of these two black 

shales. Generally, the shales have similar organic and 

inorganic geochemistry and mineralogy. 

The mineralogy of the shales is important to understanding the residence of elements and the environment of 

deposition. Pyrite is the major residence of iron and sulfur, but 

significant amounts of iron-rich chlorite are present in all 

samples. Siderite is present in some samples of the Mecca 

Quarry Shale Member in Indiana. Quartz, kaolinite, and 

potassium feldspar are the dominant detrital minerals, whereas 

ubiquitous illite, albite, iron chlorite, pyrite, apatite, and 

carbonate minerals are of early or late diagenetic origin. 

During early diagenesis, organic matter was metabolized by 

sulfate reducers to produce sulfide that reacted with iron, zinc, 

and other easily leachable or reducible metals (Cr, Ni, Mo, Se, 

U, and V). Some metals were also released from their organic 

residence site at this time. Gypsum may be of detrital origin. 

In both shales, molybdenum, selenium, nickel, vanadium, and chromium are chiefly associated with organic 

matter. We do not find the vanadium-illite association reported 

by Coveney and others (1987). The Stark Shale Member 

1

U.S. Geological Survey, P.O. Box 25046, Denver Federal Center, 

MS 905, Denver, Colorado 80225. 2U.S. Geological Survey, P.O. Box 25046, Denver Federal Center, 

MS 972, Denver, Colorado 80225. 3

U.S. Geological Survey, P.O. Box 25046, Denver Federal Center, 

MS 973, Denver, Colorado 80225. 

12 Metalliferous Black Shales and Related Ore Deposits 

generally contains less organic carbon than the 1'-1\ecca Quarry 

Shale Member, but the proportion of marine organic matter is 

higher in many units of the Stark Shale Memb~r. The Stark 

Shale Member has an equal or higher ratio of metals (Mo, V, 

Zn, Cd, Se, U, Ni, and Cr) relative to organic ca .. bon than the 

Mecca Quarry Shale Member. This may be due to higher 

availability in terms of source or to chemical cor"plex stability 

of these metals in a more offshore environment. 

INTRODUCTION 

Numerous studies of metal contents and organic 

matter compositions in Middle and Upper P::nnsylvanian 

black shales have been published during the: last decade 

(Coveney and others, 1987; Coveney and Glascock, 1989, 

and references listed therein). The present study was 

undertaken to compare the bulk mineralogy and inorganic 

and organic geochemistry for 21 samples from a 53-

em-thick section of the Upper Pennsylvanian (Missourian) 

Stark Shale Member of the Dennis Limestone in Wabaunsee 

County of eastern Kansas (Stanton and others, 1983) with 

that for 14 samples of the Middle P1~nnsylvanian 

(Desmoinesian) Mecca Quarry Shale Member of the Linton 

Formation and equivalent beds, 33-55 em thick, from Pike 

and Parks Counties, Indiana, and of the Carbondale 

Formation in Knox County Illinois (Coveney and others, 

1987). (The stratigraphic positions of the Stark Shale 

Member and the Mecca Quarry Shale Member of Indiana 

and Illinois and equivalents in Missouri and Kansas are 

shown in table 1.) Organic carbon, elemental, and 

mineralogical abundances were determined in c rder to study 
Table 1. Stratigraphic position of the Stark Shale Member 

and the Mecca Quarry Shale Member in relation to other 

Middle and Upper Pennsylvanian black shales in the 

Midcontinent, U.S.A. 

[Modified from Heckel (1977) for eastern Kansas] 

UPPERPENNSYLV~~ 

Virgilian Series 

Larsh Shale Member of the Deer Creek Limestone 

Queen Hill Shale Member of the Lecompton Limestone 

Heebner Shale Member of the Oread Limestone 

Missourian Series 

Eudora Shale Member of the Stanton Limestone 

Quindaro Shale Member of the Wyandotte Limestone 

Muncie Creek Shale Member of the lola Limestone 

Stark Shale Member of the Dennis Limestone 

Hushpuckney Shale Member of the Swope Limestone 

. MIDDLE PENNSYLV AJIHAN (PAR'l) 

Desmoinesian Series 

Anna Shale Member of the Pawnee Limestone 

Little Osage Shale Member of the Fort Scott Limestone 

Excello Shale Member of the Fort Scott Limestone 

Mecca Quarry Shale Member of the Carbondale Formation in 

Illinois and equivalents in Indiana, Missouri, and Kansas 

major and minor element associations. Of primary interest 

in this study are elements apparently associated with 

organic matter including V, Mo, Se, Zn, Cd, Ni, U, and Cr. 

ENVIRONMENT OF DEPOSITION 

Previous studies of the Mecca Quarry Shale Member 

in Illinois and Indiana indicate that it was deposited in a 

relatively near-shore marine environment, whereas Mecca 

Quarry equivalents in Missouri and Kansas were deposited 

farther offshore (Coveney and others, 1987). This conclusion is based on the ratio of terrestrial to marine organic 

matter. The relatively near-shore marine environment 

received a significantly greater contribution of detrital 

terrestrial organic matter derived from the ancestral 

Appalachian peat swamps located near the then equatorial 

latitudes (Heckel, 1977; Coveney and others, 1987), 

whereas shales that were farther offshore in Kansas received 

a larger proportion of marine organic material. 

The large interior seas in which these shales were 

deposited were bounded by low-relief highlands of the late 

Paleozoic shield on the north side, the Appalachian highlands on the east, the Ouachita-Marathon highlands on the 

south, and the ancestral Rocky Mountain uplift on the west. 

It is speculated that these interior seas had access to 

open-ocean water through an area in western Texas (Heckel, 

1977). 

The organic-rich Middle and Upper Pennsylvanian 

shales are inferred to represent maximum incursion of 

marine transgression (Heckel, 1977) during multiple sea 

level changes in North America that are now thought to 

represent the concomitant influences of tectonic activi~y and 

glacial and interglacial events in the Southern Hemirnhere 

(Kline and Willard, 1989). 

SAMPLES AND METHODS OF STUDY 

The core samples of the Stark Shale Member have 

been described by Stanton and others (1983); mega~copically, they are black to gray and massive to laminated. Some 

contain visible pyrite nodules or lenses, and sorr~ are 

phosphatic. Polished thin sections of 14 samples were 

studied in reflected and transmitted light. All of the sa~ples 

are very fine grained and consist of intimate mixtu ... es of 

minerals and organic matter . 

Organic and inorganic geochemical data and X-ray 

diffraction data were determined for splits of each srmple. 

Analytical data for carbon and sulfur are given in S'anton 

and others (1983). Selenium was determined by X-ray 

fluorescence using a cadmium radioisotope source Cl nd an 

energy-dispersive analyzer. Other elements were determined by inductively coupled plasma mass spectrometry 

using the methods of Lichte and others (1987). ~rickelfiltered Cu Ka radiation was used with a diffractomete.r scan 

rate of 2° per minute. The same operating conditior~ and 

X-ray tube were used for all analyses. Powdered sa'llples 

were backpacked into 2-mm-thick mounts. X-ray peak 

intensities reported are corrected for background. Fo .. each 

mineral, the X-ray diffraction maxima used and their 

approximate positions are given in table 2, along with 

detection limits estimated by Carroll (1970). X-ray 

diffraction analysis was done on splits from samples s~udied 

by Coveney and others (1987, tables 3 and 4), who used 

several different analytical methods. 

MINERALOGICAL RESULTS 

In addition to quartz, major and minor minerals 

detectable by X-ray diffraction include iron chlorite, illite, 

kaolinite, feldspar (albite and potassium feldspar), O'lcite, 

dolomite, apatite, pyrite, gypsum, and siderite. Data for the 

Stark samples are given in table 3; data for the I 1ecca 

Quarry and equivalent samples are given in table 4. 

Iron ch/orite.-Iron-rich chlorite is present in all of 

the Stark samples and in 12 of 14 of the Mecca Quar:)' and 

equivalent samples. Carroll (1970, table 12) observe~ that 

about 10 percent iron chlorite must be present in order to 

detect it by diffractometer using copper radiation. It is 

important to determine the abundance of this rrineral 

because it contributes significantly to the iron cont~nt of 

bulk samples; in fact, except for pyrite and siderite, it is the 

major iron host in these samples. 

/1/ite.-Dlite is present in all samples and generally is 

the most abundant clay mineral. The relative abunda'"'ce as 

Geochemical and Mineralogical Comparison of Black Shales, Kansas, Illinois, Indiana 13 
Table 2. X-ray diffraction peaks used for estimation of relative abundances of minerals other than quartz in 

Pennsylvanian shales 

Mineral hkl 

Iron chlorite .................................... 001 

Illite ............................................. 001 

Gypsum ......................................... 020 

Kaolinite ........................................ 001 

Feldspar 

a= albite ...................................... 002 

k=potassium feldspar. ..................... 040, 002 

Calcite ........................................... 1 04 

Dolomite ........................................ 1 04 

Apatite .......................................... 112 

S"d . 2 1 cr1te ........................................ 1 04 

p . 3 yr1te-py1 .................................... 002 

Pyrite-py2

4 .................................... 021 

1 

(Carroll, 1970, table 12). 

d-value used 

(angstroms) 

14.1-14.2 

10.2 

7.56 

7.15 

3.186-3.198 

3.220-3.250 

3.03 

2.88 

2.79 

2.79 

2.71 

2.42 

Approximate Lowest percentage 

2R0 (CuM) identifiable 1 

a 

6.2 1 0 

8.7 5 

11.7 Not reported 

12.4 5 

27.90-28.00 5 

27.45-27.70 5 

29.5 5 

30.96 1 

32.05 Not reported 

32.05 Not reported 

33.16 Not reported 

37.15 Not reported 

2Sidcrite cannot be detected in minor amounts due to interference of apatite. 

3 

This line of pyrite is coincident with the second strongest line (202) of apatite. This line is not reported for samples with detectable 

apatite. 

4 

This line was measured for all samples because there arc no interlercnces with other minerals. 

determined from X-ray diffraction intensity data is used 

here to evaluate the hypothesis of Coveney and others 

(1987, p. 922) that "most of the V resides in illite." 

Kaolinite.-Kaolinite is detectable in all samples; 

thus it constitutes more than 5 percent (Carroll, 1970) of 

each bulk sample. The ratio of illite to kaolinite is higher 

(1.6) for the Stark than the Mecca Quarry and equivalent 

samples (1.3). The kaolinite probably is chiefly detrital. 

Feldspar.-X-ray diffraction data and whole-rock 

chemical data for sodium indicate that authigenic albite is 

the dominant feldspar and is present in all samples. A fair 

correlation (r=0.84) exists between the intensity of the albite 

002 X-ray peak and the sodium content. Potassium feldspar 

was detected in 15 Stark samples and 3 Mecca Quarry and 

equivalent samples (tables 3 and 4). The small grain size of 

quartz and silicate minerals ( <20 micrometers) precludes 

indentification of feldspars in polished thin sections. 

Calcite.-Calcite was detected in all Stark samples 

and in 9 of 14 Mecca Quarry and equivalent samples, but its 

abundance is quite variable. Calcite is a major mineral in 

two Stark samples, both of which have very low organic 

carbon contents ( < 1 percent). 

Dolomite.-Dolomite is present in 19 of 21 Stark 

samples and in 7 of 14 Mecca Quarry and equivalent 

samples. Like calcite, its abundance is variable, but unlike 

calcite, it is not a major mineral in any of the samples. 

Apatite.-Apatite is detectable in 14 of 21 Stark 

samples and in 9 of 14 of the Mecca Quarry and equivalent 

samples. 

Pyrite .-Pyrite is a minor constituent in 19 of 20 

Stark samples and in all of the Mecca Quarry and 

14 Metalliferous Black Shales and Related Ore Deposits 

equivalents samples. Because the strongest pvrite peak is 

coincident with the second strongest apatite peak, the 

strongest pyrite peak (py1, tables 3 and 4) was measured 

only when apatite was not detected (see table 2). 

Gypsum.-Small amounts of gypsum \P~re detected 

in seven of the Stark samples and in seven <'f the Mecca 

Quarry and equivalent samples. Because the Stark samples 

are from fresh core, the gypsum is presuma.d to be an 

original constituent rather than a product of weathering. The 

samples of Coveney and others ( 1987) (Mecca Quarry and 

equivalents) are from quarries, outcrops, and a coal mine, 

and the gypsum in them possibly is the result o~ weathering. 

Siderite.-Siderite was not detected in the Stark 

samples but is present in three of the Mecca Quarry Shale 

Member samples from Indiana and lllinoi~ (table 4). 

For samples that contain apatite, however, an interference 

between the strongest siderite X-ray line and that of 

apatite may prohibit detection of minor amounts of siderite 

(table 2). 

MICROSCOPY 

Polished thin sections of samples of the Stark Shale 

Member reveal lamination on a fine scale, spa~se lenses of 

pyrite or carbonate, small phosphate nodules~ and sparse 

conodonts. Brachiopod valves are in some of tt'~ carbonaterich layers. The mineral grains are generally smaller than 

10-20 micrometers and are intimately mixed with organic 

material. Sulfide minerals are pyrite, sphalerit~. and sparse 

chalcopyrite. Pyrite is present chiefly as frrmboids and 
Table 3. Organic carbon content and X-ray diffraction intensity data for minerals, except quartz, in drill-core samples of the Upper Pennsylvanian 

Stark Shale Member of the Dennis Limestone, Wabaunsee County, Kansas 

[Depth 1,862.8-1,864.5 ft; SW1/4NE1/4SW1/4 sec. 33, T. 13 S., R. 10 E. C%, weight percent organic carbon; ill, illite; kao, kaolinite; fel, feldspar (a is albite, k is 

potassium feldspar); cal, calcite; dol, dolomite; ap, apatite; py, pyrite; gy, gypsum; sid, siderite; chl, chlorite. M indicates major mineral phase with peak greater than intensity 

100. Leaders (--)indicate apatite interference. Numbers in parentheses are estimated detection limits (in percent)] 

~ Sample C% ill kao fel cal dol ap py2 gy sid chi pyl 

tl) number (5) (5) (5) (5) (5) (1) (1) (5) (5) (5) (10) (1) 0 

1"1 S-1 21.7 23 14 16a, 6k 26 17 0 21 0 0 6 28 ::r 

tl) 

3 S-2-2 24.4 30 17 22a, 5k 19 18 8 17 0 0 8 

;:;- S-2-1 29.5 19 12 11a, 4k 20 15 0 12 0 0 4 19 e!.. 

llol S-3-2 2.0 80 57 lOa, 12k 14 13 10 8 6 0 17 :::1 

Q. S-3-1 2.1 65 48 12a, 12k 15 15 9 9 6 0 11 ~ S-4-3 7.5 25 15 25a, 6k 46 12 9 11 0 0 5 

:r 

tl) S-4-2 10.8 26 14 21a 41 10 33 9 0 0 8 ... 12 10 3 0 8 llol S-4-1 21.4 31 16 13a, 6k 22 14 Q 

cr.s. S-5 14.4 33 14 19a 17 14 12 11 4 0 5 1"1 

e!.. S-6-2 19.2 23 10 13a 13 8 0 10 0 0 7 15 

("') S-6-1 11.7 17 10 24a 23 11 0 27 0 0 4 40 0 

3 S-7 2.2 28 10 28a, 12k 48 0 5 8 0 0 6 "'C 

llol 

... S-8-2 17.9 28 15 23a, 8k 7 20 36 8 0 0 8 

iii' 

0 S-8-1 23.4 33 18 18a, 5k 11 14 24 5 0 0 6 :::1 S-9-2 0.5 13 11 14a M 6 5 0 0 0 3 0 0 

- S-9-1 0.9 23 8 26a, 7k M 0 0 0 4 0 4 5 CCI 

~ S-10 17.8 28 20 17a, 4k 33 17 16 17 0 0 7 :Ill:" S-11 13.5 27 12 24a, 7k 14 9 0 9 3 0 6 15 VI 

::r S-12-2 12.0 34 21 27a, 6k 17 6 5 13 0 0 9 e!.. 

tl) S-12-1 23.6 25 15 18a 26 15 10 17 6 0 5 ~ 

~ S-13 1.6 46 18 32a, 8k 61 16 7 6 0 0 10 :::1 

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;; 

c 

til 

1 

a: 

Table 4. Organic carbon content and X-ray diffraction intensity data for minerals, except quartz, in Pennsylvanian black shales in the Midcontinent region 

[From Coveney and others (1987). C%, weight percent organic carbon; ill, illite; kao, kaolinite; fel, feldspar (a is albite; k is potassium feldspar); cal, calcite; dol, dolomite; 

ap, apatite; py, pyrite; gy, gypsum; sid, siderite; chl, chlorite; leaders (--)indicate apatite interference; N.A. indicates not analyzed. Numbers in parentheses are estimated 

detection limits (in percent)] 

Sample C% 

Bed A(3) ......... 31.5 

Upper B(2) ...... 37.5 

BedC .............. 6.4 

BedB ............ 36.8 

BedD ............ l4.7 

Bed A(3) ......... 39.3 

Bed B(2) ......... 32.7 

BedC .............. 9.6 

BedD ............ 27.9 

BedB ............. .N.A. 

Bed A7 ........... 10.2 

Bed A6 ............. 7.6 

Bed A1(2) ......... 7.6 

BedB ............ 18.5 

ill 

(5) 

22 

20 

20 

29 

12 

kao 

(5) 

fel 

(5) 

cal 

(5) 

dol 

(5) 

ap 

(1) 

py2 

(5) 

gy 

(5) 

Mecca Quarry Shale Member, Linton Formation, Hesler Farm, Mecca, Parke County, Indiana 

21 13a 0 5 0 19 3 

15 lOa 0 0 0 14 5 

20 20a 9 0 14 9 0 

22 

14 

Mecca Quarry Shale Member, east of Velpen, Pike County, Indiana 

14a, 6k 2 0 6 1 9 

9a 21 0 0 23 

7 

11 

Mecca Quarry Shale Member, Carbondale Formation, Court Creek, Knoxville, I<nox County,lllinois 

sid 

(5) 

5 

7 

0 

0 

0 

24 11 7a, 6k 3 0 25 5 2 0 

22 12 7a 0 3 13 9 0 0 

22 12 16a 0 0 0 8 0 0 

1 9 14 9a, 7k 7 7 3 9 6 0 0 

Mecca Quarry Shale Member, Carbondale Formation, Lowell, LaSalle County, centrallllinois 

18 9 9a 0 0 0 8 6 15 

Shale in Verdegris Limestone Member, Cabaniss Formation, coal mine, Fort Scott, Bourbon County, Kansas 

19 15 4a 16 26 38 15 0 0 

23 37 14a 5 15 17 10 0 0 

23 16 17a 44 17 15 22 0 0 

Shale in Verdegris Formation, drill-hole BM-2, Randolph County, Missouri 

22 12 6a 88 10 28 9 5 0 

chi 

(1 0) 

4 

5 

6 

3 

0 

3 

4 

6 

5 

0 

4 

3 

4 

5 

py1 

(1) 

26 

23 

37 

12 

18 
aggregates of framboids; some pyrite associated with 

carbonate lenses or phosphate nodules is present as discrete 

grains or crystals. Pyrite replaces parts of brachiopod 

valves. Sphalerite generally is present as grains smaller than 

10 micrometers in diameter but is larger in some phosphate 

nodules and incipient replacement of brachiopod values. 

Local mantling of pyrite framboids by both sphalerite and 

sparse chalcopyrite indicates that the sphalerite and chalcopyrite formed later than the framboids. In some samples 

there are two distinct types of organic material; one is red 

and translucent, whereas the other is opaque. 

ASSOCIATION OF ELEMENTS WITH 

MINERALS OR ORGANIC MATTER 

Tables 5 and 6 give chemical data for 22 major, 

minor, and trace elements in the Stark samples from 

Wabaunsee County, Kansas. These chemical data, together 

with X-ray diffraction data (tables 3 and 4) and studies of 

polished sections, were used to determine the associations 

of elements with each other and with the relative 

abundances of minerals or content of organic carbon for 

each sample. We used the chemical data of Coveney and 

others (1987, tables 2 and 3) for the 14 sample splits of the 

Mecca Quarry and equivalents for which we report X-ray 

diffraction data on bulk samples (table 3). 

Iron, sulfur, pyrite, and iron chlorite.-Pyrite commonly is assumed to be the major host of iron and sulfur in 

these shales (Coveney and others, 1987, fig. 5). Although 

this generally is the case, other minerals may be present that 

contain these elements in significant amounts. X-ray 

diffraction results (table 4) show that three of the samples of 

Coveney and others ( 1987) contain both siderite and 

gypsum, and four others contain minor gypsum. The 

relations between total sulfur and iron are shown for the 

Stark samples on figure 1; a "pyrite line" illustrates the 

relations that would be observed if all of the sulfur and iron 

were only in pyrite. Except for one sample, all of the data 

points lie on the "excess iron" side of the pyrite line. 

Because gypsum is present in two of these samples (table 4), 

it is inappropriate to assume that all of the sulfur is in pyrite. 

Figure 2 shows the relations between total sulfur and the 

intensity of the pyrite peak (py2, table 3) for samples of the 

Stark; although there is a gross correlation between these 

two parameters, there is a great deal of scatter. Figure 3 

shows the relations between total iron content and the 

intensity of the pyrite peak (py1, tables 3 and 4) for samples 

of Stark Shale Member and Mecca Quarry Shale Member 

that contain no detectable apatite (thus there is no 

interference between the apatite peak and the strongest peak 

of pyrite). Based on projection of the zero pyrite peak 

intensity onto the total iron content line (fig. 3), it is clear 

that about 1.5-1. 7 weight percent of the iron present in these 

samples is not in pyrite; rather, it is in chlorite or siderite, or 

both, for several of the samples. 

Vanadium, organic matter, and illite.-Coven~y and 

others (1987, p. 922) and other workers have suggested 

"most of the V resides in illite" because of the correspondence of the scanning electron microscopy-energy 

dispersive analytical X-ray results for potassium anc vanadium (Coveney and others, 1987, fig. 4). However, carbon 

and molybdenum data on their figure 4 can be interpreted to 

show that potassium in the clay and the organic coatings is 

intermixed with the clay. Our figure 4 shows illit~ p~ak 

intensity versus vanadium content for both samples of the 

Stark and Mecca Quarry and equivalents; there is no 

correlation between the abundance of illite and the 

concentrations of vanadium. Figure 5 shows organic carbon 

content versus vanadium content for samples of th~ Stark 

and Mecca Quarry and equivalents of Coveney and others 

(1987). The correlation coefficient (r) for 15 of the 19 

Mecca Quarry samples is 0.81, significant at the 0.01level, 

and indicates that vandadium is associated statistical':·· with 

organic carbon. For 18 of the 21 Stark Shale Member 

samples the correlation between vanadium and organic 

carbon is also high (r=0.95). Some data points for eac, shale 

unit are enclosed on figure 5 to emphasize the different 

ratios of vanadium to organic carbon. 

The concentration ratio (ppm V /percent TOC) is 

higher for samples of the Stark compared to the Mecca 

Quarry, as shown by (1) the slopes of the trends on figure 5, 

(2) comparison of the weighted means (percent of interval 

of each bed multiplied by the concentration of each element, 

summed for all beds in each interval (see table 7), and 

(3) the mean values of organic carbon and vanadiu'll (see 

table 7). For samples of the Mecca Quarry from Pike and 

Parke Counties, Indiana, weighted means are 26.1 percent 

..1-J 

c 

Q) 

L 

Q) 

c. 

..1-J 

.!:. 3 Ol 

·ri • Q) • • ~ 

• • c 2 • ·ri • • • • 

• • 

c.: • ::l 

'+-

...-1 • ::l 

en 

0 

0 1 2 3 4 5 6 

Iron. in weight percent 

Figure 1. Relations between total sulfur and iron for 5'amples 

of the Upper Pennsylvanian Stark Shale Member of the Dennis 

Limestone, Wabaunsee County, Kansas. The line fo· pyrite 

shows the relations if all the iron and sulfur are only ir pyrite. 

Geochemical and Mineralogical Comparison of Black Shales, Kansas, Illinois, Indian,. 17 
.... 

CCI 

~ 

!!. 

!:: 

;; 

.. 

Q 

c 

.., 

ii = 

n 

:11:" 

tl) 

::r 

!.. 

I'D 

.., 

I» Table 5. Selected major and minor elements in the Stark Shale Member of the Dennis Limestone, Wabaunsee County, Kansas ::I 

Q. 

[In weight percent. Organic carbon and sulfur values are from Stanton and others (1983); other elements determined by inductive coupled plasma method] ~ 

I'D 

~ Samele O~anic C AI Fe Mg Ca Na K 1i p s Q. 

0 S-1 21.7 5.9 4.7 1.5 2.4 0.64 0.48 0.24 0.05 4.1 

;;; S-2-2 24.4 5.8 3.5 1.5 1.9 0.62 0.53 0.23 0.11 2.7 

c 

I'D S-2-1 29.5 4.8 3.8 1.5 2.8 0.47 0.41 0.20 0.12 3.3 "'C 

Q S-3-2 2.0 11.0 4.3 1.7 0.4 0.36 1.5 0.39 0.03 2.0 .., 

~ S-3-1 2.1 11.0 4.3 1.7 0.4 0.28 1.5 0.37 0.02 2.0 

S-4-3 7.5 7.6 3.5 1.6 4.3 0.97 0.68 0.29 0.59 2.5 

S-4-2 10.8 5.6 2.9 1.2 10.0 0.82 0.47 0.23 3.2 2.2 

S-4-1 21.4 6.1 3.3 1.4 2.9 0.66 0.56 0.23 0.54 2.6 

S-5 14.4 8.0 3.4 1.6 2.3 0.93 0.79 0.29 0.51 2.1 

S-6-2 19.2 6.7 4.5 1.5 1.7 0.70 0.56 0.28 0.05 3.8 

S-6-1 11.7 7.1 5.8 1.6 2.6 1.20 0.68 0.27 0.08 5.0 

S-7 2.2 9.7 3.2 1.6 3.1 1.60 0.91 0.37 0.11 1.6 

S-8-2 17.9 5.6 2.4 1.4 7.8 0.90 0.44 0.19 2.90 1.8 

S-8-1 23.4 6.1 2.5 1.4 4.3 0.72 0.54 0.21 1.50 1.7 

S-9-2 0.5 4.2 2.9 0.8 18.0 0.75 0.28 0.16 0.18 2.0 

S-9-1 0.9 7.4 2.0 1.3 9.8 1.50 0.63 0.30 0.08 1.0 

S-10 17.8 6.1 4.5 1.5 4.5 0.69 0.47 0.20 0.86 3.8 

S-11 13.5 7.6 3.4 1.6 2.4 1.20 0.67 0.29 0.41 2.2 

S-12-2 12.0 7.5 4.7 1.5 2.1 1.20 0.62 0.30 0.13 3.6 

S-12-1 23.6 5.5 4.1 1.4 2.9 0.66 0.41 0.20 0.31 3.8 

S-13 1.6 8.6 3.5 1.8 4.5 1.10 0.72 0.36 0.19 1.4 
Table 6. Minor and trace elements in the Stark Shale Member of the Dennis Limestone, Wabaunsee County, Kansas 

[In parts per million. Selenium determined by energy-dispersive analysis, other elements by the inductive coupled plasma method. nd indicates not determined] 

Sam~le Ag As Ba Cd Cr Mo Ni Se Sr u v Zn 

C') S-1 4 40 180 160 660 320 470 140 160 60 2,600 3,100 

" S-2-2 3 30 180 220 760 520 600 195 160 120 3,500 3,800 0 

n S-2-1 9 40 160 230 730 670 600 nd 180 180 3,900 5,500 ::r 

" S-3-2 <2 20 490 7 100 29 69 <10 87 <40 210 82 3 

[ S-3-1 <2 <10 480 6 100 25 69 <10 88 <40 190 62 

I» S-4-3 2 50 240 12 210 67 260 50 330 <40 760 310 

Q. = S-4-2 4 40 190 52 200 150 290 65 730 150 1,200 890 

~ S-4-1 5 30 190 210 390 760 490 125 280 180 3,600 2,900 s· S-5 5 20 230 30 730 93 280 110 260 50 620 1,100 " i. S-6-2 7 50 210 150 370 820 540 185 170 70 3,200 2,500 0 

OCI S-6-1 7 70 720 75 240 630 370 170 220 120 2,000 1,800 ;::;· 

!.. S-7 <2 30 860 6 130 15 110 15 360 <40 110 130 

n S-8-2 5 10 520 27 870 67 310 85 580 70 370 1,400 0 

3 S-8-1 5 10 180 22 1,100 91 380 110 380 40 490 1,100 ~ 

I» S-9-2 <2 30 87 2 51 30 49 <10 1,200 <40 42 32 g· S-9-1 <2 20 800 5 83 6 60 <10 680 <40 64 70 

= S-10 8 30 200 110 720 180 350 125 320 120 1,600 2,200 0 

- S-11 6 20 720 69 770 170 310 30 260 60 1,100 1,400 = 

~ S-12-2 7 50 670 90 310 440 320 125 210 170 2,300 2,100 Jll:'" S-12-1 7 40 190 150 540 850 450 145 250 290 3,500 3,900 V) 

S-13 <2 20 290 6 150 13 100 25 320 <40 150 110 ::r 

!.. 

~ " 

~ 

= 

~ 

s· 

!2. 

~ 

;' 

Q. 

;;· 

J 

i» 

.... 

\C 
6 Explanation 

0 py1 

• py2 

5 • 0 

4-) 

c 

Q) 

u 

L • Q) 0 4 0. 0 •• • g 4-) • .c 

()) • 0 

·r-f 

Q) 3 ~ • .. ge • 

L ••g 0 :J eg \f- 2 Qe •g r-t 

:J • 

{/) • • 

• 

1 0 

0 ~----~------~-------+------~------~-------r------~------~ 

0 10 20 30 40 

pyrite. peak intensity (XRD) 

Figure 2. Relations between total sulfur and intensity of pyrite peaks py1 and py2 for samples of the Stark Shale Member of the 

Dennis Limestone, Wabaunsee County, Kansas. g indicates that gypsum was detected. 

total organic carbon (TOC) and 1,618 ppm V and 25.0 

percent TOC and 1,725 ppm V, respectively. For samples of 

the Stark in Wabaunsee County, Kansas, weighted means 

are 12.7 percent TOC and 1,831 ppm V. Concentration 

ratios (ppm V /percent TOC) for the Mecca Quarry samples 

are 62 and 69 and for the Stark samples 144 (table 7). In 

other words, organic matter in the Stark samples contains 

almost twice as much vanadium as does organic matter of 

the Mecca Quarry samples. 

Uranium.-Figure 6 shows no apparent relationship 

between uranium and phosphorous contents of the Stark 

samples. The uranium and phosphorous data of Coveney 

and others ( 1987, table 2) show similar distributions. 

Swanson (1960) found that in some black shales of 

Pennsylvanian age, uranium apparently is associated with 

phosphorous (apatite). Although the weighted mean values 

for uranium of the Mecca Quarry are higher than the 

20 Metalliferous Black Shales and Related Ore Deposits 

weighted mean values of the Stark, the ratios of uranium to 

organic carbon (ppm U/percent TOC) (table 7) are higher 

for the Stark. 

Arsenic.-Contents of arsenic in the Star!-: are from 

less than 10 ppm to 70 ppm. The apparent correlation 

(r=0.6) between the arsenic content and the inter«ity of the 

pyrite (py2) peak (fig. 7) indicates that arsenic is present 

chiefly in pyrite. 

Selenium.-Figure 8 shows the relations b~tween the 

selenium content and organic carbon content for samples of 

the Stark. For these samples selenium probably is associated 

chiefly with organic matter. Although the absokte amount 

of selenium is higher for samples of Mecca Quarry in 

Indiana (bed B) than for samples of the Stark (table 7), the 

ratios of selenium concentration to total orga""'ic matter 

content are not statistically different (6.8 versu~ 6.3 ppm 

Se/percent TOC, table 7). 
401 • ~ ~ 0 

> 

!:: 

Ul • c:: 0 CD 

..... 0 .s 

.lt. 

co 0 • Ill 

a. • • 0 ... 

> 

.s 

UJ 

1- • 1-f 

a: 

> a. 0 

0 2 3 4 5 6 

Iron, weight percent 

Figure 3. Relations between total iron content and intensity 

of the strongest pyrite peak (pyl) for samples of the Stark Shd:e 

Membe~ (solid square). and Mecca Quarry Shale Member 

(open c1rcle) that contam no detectable apatite as indicated 

using X-ray diffraction. 

Nickel.-The association between nickel and organic 

carbon content for the Stark samples is shown on figure 9. 

Data for five samples of the Mecca Quarry and equivalents 

from Indiana, illinois, Missouri, and Kansas (Coveney and 

others, 1987) are also shown. The weighted mean values for 

bed B of the Mecca Quarry in Indiana are 450 ppm Ni and 

35.7 percent organic carbon (table 7). The weighted mean 

values for the Stark samples are 290 ppm Ni and 12.7 

percent organic carbon. The calculated concentration ratio 

(table 7) for the Stark is almost twice that for the Mecca 

Quarry. 

Zinc.-Zinc is present chiefly in sphalerite that is 

generally very fine grained (<5 micrometers); however, for 

11 of 15 samples of the Stark the correlation between 

organic matter content and zinc content is good (fig. 10). 

For some of the Stark Shale samples the relationship 

between the contents of zinc and phosphorous is inverse. 

We do not understand this relationship because in the 

polished thin sections neither apatite nor sphalerite replace 

each other. Table 7 shows the weighted means and means 

and concentrations ratios for zinc (ppm/percent organic 

carbon) for the Mecca Quarry and the Stark. With the 

ex~ep_tion of the Mecca Quarry samples from Knox County, 

Illmms, the ratio of zinc to organic carbon is considerably 

higher for samples of the Stark Shale Member. 

. Molybdenum.-The absolute amount of molybdenum 

m the Mecca Quarry samples is significantly higher than in 

the Stark Shale Member samples (table 7). Molybdenum 

probably is mostly associated with organic carbon but does 

not correlate well with organic carbon content (Coveney 

and others, 1987, fig. 3). Figure 12 shows pyrolysis gas 

chromatograms (for experimental method see Leventhal 

1981) for two Stark samples that have similar organi~ carbon contents. Sample S-8-2 containing 67 ppm Mo is 

mainly marine-sourced organic matter as indicated by 

the predominance of n-alkanes. In contrast, sample S-6-1 

containing 630 ppm Mo has a significant propo'tion of 

land-sourced organic matter as indicated by the nan-nalkane components. Similar pyrolysis gas chroma .. 0grams 

for samples of the Mecca Quarry from different localities 

show that samples have variable amounts of la""d- and 

marine-derived organic matter (Coveney and other~. 1987) . 

Although the concentration ratios (mean values) of molybdenum to organic carbon (table 7) for the Mecca Qw~rry and 

the Stark are not significantly different, the highest molybdenum contents are associated with samples h1ving ·a 

substantial terrestrial organic matter component (Coveney 

and others, 1987). 

Chromium.-There is some association between 

chromium and organic carbon contents, but there is considerable scatter of the data. In the absence of recor!nizable 

chromium-bearing minerals, it is assumed that chro'llium is 

associated with organic matter. The weighted mean data and 

the concentration ratios of chromium to organic ca .. bon for 

Mecca Quarry and Stark samples show that, althou ~h there 

is more chromium in bed B in Indiana than in the S ~ark, the 

ratio of chromium to organic carbon in the Stark is about 

twice that of the Mecca Quarry in Indiana. 

Association of zinc and nickel.-Figure 13 illustrates 

the association of zinc and nickel in organic-rich marine 

strata of Devonian and Mississippian age and in the Stark 

and Mecca Quarry samples. Even though zinc is present 

chiefly in sphalerite and nickel is correlated with organic 

carbon, the relationship between the concentrations of these 

two elements is generally linear (fig. 12), except wl,~re zinc 

has been mobilized (enriched with respect to nickel) or is, at 

least in part, of epigenetic origin. For example, the Mecca 

Quarry sample having the highest concentration (nct. shown 

on fig. 13) of zinc (5,300 ppm, Coveney and others, 1987, 

table 3) is one that has some epigenetic zinc, as eYidenced 

by anomalously high concentrations of sulfur, iron, and 

barium compared to the other samples. Geochemical profiles for zinc and nickel in the Devonian and Missi ~sippian 

New Albany Shale in Indiana (Beier and Haye~, 1989, 

fig. 3) likewise show that nickel and zinc have prop,rtional, 

or somewhat constant, concentration relations exce:-Jt where 

sphalerite-rich phosphate nodules are prese~t (B~ier and 

Hayes, 1989, fig. 2). The reason for the relativeJy linear 

relation of zinc and nickel in these organic-rich Dwonian, 

Mississippian, and Pennsylvanian strata is not knov·n, but it 

is probably related to the availability and the solul-,ility of 

both of these metals. 

SUMMARY 

Integrated mineralogical and chemical stndies of 

metalliferous marine black shales of Pennsylvanian age 

provide clues to the relationships of element residence in 

minerals and organic matter. 

Geochemical and Mineralogical Comparison of Black Shales, Kansas, Illinois, lndia~a 21 
80 

70 

• -

0 

a: 

X 60 

>-

4J 

·rl 

en 50 c 

Q) 

-+-> • c 

·r-1 

.::L 40 

co 

Q) 

0. • . • • 

• • Q) 30 0 -1-) 

·r-1 • • r-1 •• r-1 • 0 • 

0 ·r-1 0 0 0 • • 0 

20 co 0 

0 • • 

0 

10 

0 500 1000 1500 2000 2500 3000 3500 4000 

Vanadium. ppm 

Figure 4. Relations between illite peak intensity and content of vanadium for samples of the Stark Shale Member (solid squares), 

Wabaunsee County, Kansas, and for samples of the Mecca Quarry Shale Member and equivalents in the Midcontin~nt region 

(open circles). Vanadium values for the Mecca Quarry and equivalents are from Coveney and others (1987, table 2). 

The ubiquitous occurrence of iron-rich chlorite in 

these strata and the less common presence of siderite 

reflects the presence of iron that is not in sulfide. Gypsum, 

which is present in fresh core samples, contributes 

significantly to the total sulfur content. The quality of X-ray 

diffraction data for samples of the Stark Shale Member 

studied here is indicated by a very high correlation (r=0.92) 

between the apatite peak intensity and the content of 

phosphorous. 

Chemical data alone cannot be used to determine the 

proportions of marine versus humic organic matter or the 

22 Metalliferous Black Shales and Related Ore Deposits 

relative degree of oxidation of these two types of material. 

Nevertheless, general trends exist in the metal{TOC ratios of 

the so-called near-shore versus offshore shales as shown in 

table 7. The Stark Shale Member (offshore) hrl) considerably higher metal/TOC ratios for V, Zn, Cd, Ni, and Cr. 

These higher ratios may be related to factors such as salinity 

and pH, degree of oxidation of organic matter, or type of 

organic matter. 

For both the Mecca Quarry Shale Member and the 

Stark Shale Member, Mo, Se, Ni, V, and Cr are associated 

with organic matter. 
-c 

0 

.0 

L 

ro 

u 

u 

·rl 

c 

ro 

Ol 

L 

0 

Vanadium. ppm 

Figure 5. Relations between organic carbon content and content of vanadium for samples of the Stark Shale Membe.r (solid 

squares), Wabaunsee County, Kansas and for samples of the Mecca Quarry Shale Member and equivalents (open circles) from the 

Midcontinent region. Vanadium values for the Mecca Quarry and equivalents are from Coveney and others (1987, 

table 2). LineS encloses 18 of 21 Stark samples; line M encloses 7 of 11 Mecca Quarry samples. 

REFERENCES CITED 

Beier, J.A., and Hayes, J.M., 1989, Geochemical and isotopic 

evidence for paleoredox conditions during deposition of the 

Devonian-Mississippian New Albany Shale: Geological 

Society of America Bulletin, v. 101, p. 774-782. 

Carroll, Dorothy, 1970, Clay minerals-A guide to their identification: Geological Society of America Special Paper 

126, 80 p. 

Coveney, R.M., Leventhal, J.S., Glascock, M.D., and Hatch, J.R., 

1987, Origins of metals and organic matter in the Mecca 

Quarry Shale Member and stratigraphically equivalent beds 

across the Midwest: Economic Geology, v. 82, p. 915-933. 

Coveney, R.M., and Glascock, M.D., in press, A review of the 

origins of metal-rich Pennsylvanian black shales, central 

U.S.A., with an inferred role for basinal brines: Applied 

Geochemistry, v. 2, p. 543-561. 

Desborough, G.A., and Poole, F.G., 1983, Metals in marine black 

shales of the Western United States: Society of Economic 

Geologists/ American Institute of Mining and Engineering, 

Cameron Volume on Unconventional Mineral Resources, 

p. 99-110. 

Derkey, P.D., Abercrombie, F.N., Vuke, S.M., and Daniel, J.A., 

1985, Geology and oil shale resources of the Heath 

Formation, Fergus County, Montana: Montana Brreau of , 

Mines and Geology Memoir 57, 100 p. 

Heckel, P.H., 1977, Origin of phosphatic black shale f<>des in 

Pennsylvanian cyclothems of mid-continent North P. merica: 

American Association of Petroleum Geologists Pulletin, 

v. 61, p. 1045-1068. 

Kline, G. deV., and Willard, D.A., 1989, Origin of the P~nnsylvanian coal-bearing cyclothems of North P merica: 

Geology, v. 17, p. 152-155. 

Leventhal, J.S., 1981, Pyrolysis gas chromatography-rna"~ spectrometry to characterize organic matter and its relationship 

to uranium in Appalachian Devonian shales: Geochimica 

et Cosmochimica Acta, v. 45, p. 883-889. 

Lichte, F.E., Golightly, D.W., and Lamothe, P.L 1987, 

Inductively coupled plasma-atomic emission spectrometry, 

in Baedecker, P.A., ed., Methods for geochemical analysis: 

U.S. Geological Survey Bulletin 1770, p. B1-10. 

Stanton, M.R., Leventhal, J.S., and Hatch, J.R., 1983, Shcrt-range 

vertical variation in organic carbon, carbonate carb"n, total 

sulfur contents and Munsell color values in a core from the 

Upper Pennsylvanian Stark Shale Member of the Dennis 

Limestone, Wabaunsee County, Kansas: U.S. Ge.'1logical 

Survey Open-File Report 83-315, 8 p. 

Swanson, V.E., 1960, Oil yield and uranium content of black 

shales: U.S. Geological Survey Professional Paper 35frA, 

44p. 

Geochemical and Mineralogical Comparison of Black Shales, Kansas, Illinois, lndiar~ 23 
~ 

ol:ao 

~ ~ 

~ 

a 

c 

Ill 

i» = 

n 

:11:" 

VI 

:r 

e!.. 

!l 

Ill 

::s 

Q. 

~ 

i» 

[ 

0 

~ 

c 

I'D 

"'C 

~ 

~ 

Table 7. Weighted mean and mean and calculated concentration ratios for several metals relative to the organic carbon content for the 

Mecca Quarry Shale Member of the Carbondale Formation in Illinois and of the Linton Formation in Indiana and the Stark Shale Member of 

the Dennis Limestone in Wabaunsee County, eastern Kansas 

[Weighted mean is the percent of total interval represented by sample X element concentration in sample, summed for total interval. All elements in parts per million 

except organic carbon (C, org), which is in weight percent] 

1\.'EAR -SHORE SHALE 

Mecca Quarry Shale Member, Pike County, Indiana <54.6 em-beds A, B, C, and D. Data from Coveney and others (1987, table 2) 

Mo V 7n U C. org 

Weightedmean ................................ 1,373 1,618 1,077 97 26.1 

ppm/percent C,org ................................ 52.6 62 41.3 3. 7 

Mecca Quarry Shale Member, Parke County, Indiana (38.4 em-beds A, UB, LB, C and D) 

Wcightedmean ................................ 1,078 1,725 1,782 128 25.0 

ppm/percent C,org ................................ 43.1 69 71.3 5.1 

Mecca Quarry Shale Member, Knox County, Illinois (54.4 em-beds A, B, C, and D) 

W cighted mean .................................. .451 2, 620 4,171 84 33.6 

ppm/percent C,org ................................ 13.4 78 124 2.5 

Mecca Quarry Shale Member bed B only in Pike and Park Counties, Indiana and Knox County, Illinois. Calculated from Coveney and others (1987, table 3) 

Mo V Zn Cd Se U Ni Cr C. org 

Weighted mean ........ 1,530 3,300 2,550 117 243 135 450 626 35.7 

ppm/percent C,org ........ 42.9 92.5 71.5 3.3 6.8 3.8 12.6 17.6 

OFFSHORE SHALE 

Stark Shale Member of the Dennis Limestone, Wabaunsee County, Kansas (53 em, all 21 beds of entire interval, tables 3 and 4) 

Mo V Zn Cd Se U Ni Cr C.orl.! 

Weightedmean ........... 539 1,831 1,567 75 80 75 290 448 12.7 

ppm/percent C,org ........ 46.6 144 123 5.9 6.3 6.2 22.8 35 
E 

c. 

c. 

E 

:J 

•r-t 

c 

co 

L 

:::> 

300 

250 

200 

150 • 

100 

• 

50 

detection limit 

0 ~----~------~------~------~----~------~------~---__j 

0 1 2 3 4 

Phosphorous. weight percent 

Figure 6. Concentrations of uranium and phosphorous in samples of the Stark Shale Member, Wabaunsee County, t'ansas. 

Geochemical and Mineralogical Comparison of Black Shales, Kansas, Illinois, Indiana 25 
30 

• 

25 

• 

20 

a 

a: 

~ 

...., >- I • ..... 

rn 15 c: 

QJ 

...., • c: 

•r1 

~ • • • co 

Q) 

a. 10 • • • • ai 

...., • • • ..... 

t. • >-

D.. 

5 • 

0 

0 10 20 30 40 50 60 70 80 

Arsenic, PPM 

Figure 7. Relations between pyrite peak intensity (py2) and arsenic content for samples of the Stark Shale Member, Wabaunsee 

County, Kansas. Arsenic values were reported in 1 0-ppm intervals. 

26 Metalliferous Black Shales and Related Ore Deposits 
E 

Cl. 

0. 

E 

:::J 

·rl 

c 

Q.) 

r-t 

Q.) 

(f) 

50 

0 

0 

• 

• 

• 

• • 

• • • 

• • 

• 

• 

• 

• 

10 20 30 

Organic carbon. wt. % 

Figure 8. Concentrations of selenium and organic carbon 

in samples of the Stark Shale Member, Wabaunsee County, 

Kansas. 

E 

c. 

c. 

r-t 

Q) 

.Y 

u 

·r-1 

z 

• 

• • 

•• • • OKS 

• • OMO 

• 

• 

• 

• 

• • 

0 IN 

O IN 

0 IL 

0 ~----~----~~----~----~ 

0 10 20 30 40 

Organic Carbon, wt. % 

Figure 9. Relations between nickel and organic carbon 

contents for samples of the Stark Shale Member (solid squares) 

and Mecca Quarry Shale Member and equivalents of Coveneyand others (1987, table 3) (open circles). IN, Indiana; ll, 

Illinois; MO, Missouri; KS, Kansas. 

Geochemical and Mineralogical Comparison of Black Shales, Kansas, Illinois, lndia""'a 27 
E 

D. 

Q_ 

u 

c 

·rl 

7,000 

6,000 

5,000 

4,000 

N 3,ooo 

2,000 

1,000 

> 3 wt. %Organic Carbon 

• 

• 

10 

• 

• 

• 

• • 

• 

• 

20 

• • 

•• 

• 

Organic Carbon. 

• 

30 

wt. % 

40 

Figure 10. Relations between organic carbon and zinc contents for samples of the Stark Shale Member, Wabaunsee County, 

Kansas, containing more than 3 weight percent organic carbon. 

28 Metalliferous Black Shales and Related Ore Deposits 
13 

4 

3 

ill! 

"'"' 3 2 

ui 

::::J 

0 

'-0 

J:: 

c. 

II) 

0 

.t:. 

a. 

0 0 2 3 4 !5 6 

3 

Zinc X 10, ppm 

Figure 11. Concentrations of phosphorous and zinc in 

samples of the Stark Shale Member, Wabaunsee County, 

Kansas, containing more than 3 weight percent organic 

carbon. 

RETENTION TIME ~ 

S-6-1 

S-8-T 

Figure 12. Chromatograms of pyrolysis products from samples S-6-1 and S-8-T ofthe Stark Shale Member. Organic matter in 

sample S-8-T is predominantly marine sourced material as shown by the dominance of n-alkanes (numbers indicate nu'llber of 

carbon atoms). Organic matter in sample S-6-1 is a mixture of marine and terrestrial material as shown by the abundance of other 

hydrocarbons (mainly marked "X"). 

Geochemical and Mineralogical Comparison of Black Shales, Kansas, Illinois, lndiar:<\ 29 
E 

c. 

c. 

(T') 

0 

~ 

X 

u 

c 

•r-1 

N 

16 

10 

8 

a a 

EXPLANATION 

• Upper Pennsylvanian Stark Shale Member 

of the Dennis Limestone,Kansas )( 

o Middle Pennsylvanian Mecca Quarry Shale Member of Carbondale 

and Linton Formations and equivalents, Midcontinent (Coveney 

and others, (1987) 

a Mississippian Heath Formation. Montana 

x Devonian Woodruff Formation, Nevad: 

)( X 

)( 

)( 

)( 

a 

• )( )( 

)( • • )( 

o•• 

0 

a • a a.• a o • a D~ 0 •a • • 

0~----~------~------~------~------~----~------~ 

0 2 4 6 8 10 12 14 

Nickel X 10 2 . ppm 

Figure 13. Relations between zinc and nickel contents of Devonian, Mississippian, and Pennsylvanian marine 

shales containing more than 3 weight percent organic carbon. Mecca Quarry Shale Member and equivalents cata 

from Coveny and others (1987); Heath Formation data from Derkey and others (1985); Woodruff Formation cata 

from Desborough and Poole (1983). 

30 Metalliferous Black Shales and Related Ore Deposits 
Organic Ligands and Metal-Organic Complexing 

in Ore Fluids of Sedimentary Origin 

By Thomas H. Giordano 1 

Abstract 

A variety of chemical models have been developed 

during the past 50 years to describe the genesis of those ores 

linked to diagenetic processes within sedimentary basins 

(classic Mississippi Valley-type deposits; early-rift deposits; 

metal-rich shale deposits; and copper-lead-, and uraniumsandstone deposits). Recently, efforts have been initiated by 

several investigators to study metal-organic complexing as a 

means of metal transport in ore fluids responsible for these 

types of deposits, in particular Mississippi Valley-type ore 

solutions. Although many of the aqueous organic species 

detected in modern sedimentary basins are capable of forming 

metal-organic complexes, the most promising organic ligands 

detected in deep sedimentary basin waters are acetate, 

oxalate, malonate, and succinate. For some important rockforming and ore-forming metals, thermodynamic data now 

exist for acetate complexes in the range 25-300 °C; however, 

the data base for complexes of acetateand other ligands is 

deficient, in that data are available mostly for temperatures 

near 25 oc for many metal-acetate complexes and for most 

complexes involving other possibly important organic ligands. 

Speciation models for metal-organic complexes in a 

hypothetical sedimentary basin brine and in reconstructed 

Mississippi Valley-type ore solutions have been developed 

based on high-temperature thermodynamic data for acetate 

complexes of Na+, Zn2+, Fe2+, Pb2+, and Al 3+; lowtemperature data (near 25 °C) for acetate complexes of 

competing metals, oxalate complexes, malonate complexes, 

succinate complexes, and catechol complexes; and the 

available thermodynamic data on chloride, carbonate, sulfate, 

and hydroxide complexes. These models suggest that acetate 

complexes and to a lesser extent complexes involving oxalate, 

malonate, succinate, and catechol can account for significant 

percentages of dissolved Ca, Mg, Pb, Zn, Fe, and AI in 

oxidized and slightly acid basinal brines and ore fluids having 

similar chemistry. The basinal brine model presented in this 

paper shows that metal-organic complexes may be important 

in transporting lead, zinc, and other metals in warm, oxidized 

ore fluids similar to those proposed elsewhere for red1

Department of Earth Sciences, New Mexico State University, 

Las Cruces, New Mexico 88003. 

bed-related copper- rich shales. Future efforts to produce 

reliable ore transport and deposition models for ~dimenthosted deposits must focus on the procurement of wellconstrained geochemical parameters as w~ll as 

comprehensive and reliable thermodynamic data. 

INTRODUCTION 

The formation and migration of petroleum and natural 

gas have been extensively investigated during the past 50 

years, and it is now widely accepted that these comllodities 

were formed by diagenetic processes related to tb~ evolution of sedimentary basins (Tissot and Welte., 1984). 

Sedimentary basins and related diagenetic proce~'\es can 

also be unequivocally linked to the genesis of kw-grade 

metal-rich black shales (Tourtelot, 1979) and sone basemetal and uranium deposits (Amstutz and Bernard, 1976; 

Wolf, 1976; Bjorlykke and Sangster, 1981; Gustafson and 

Williams, 1981; Nash and others, 1981). In table 1 are listed 

five major deposit-types that are typically hosted by 

cratonic, basinal sedimentary rocks and that are th,ught to 

be formed by hydrogeochemical processes within sedimentary basins. A variety of geochemical models have been 

developed to describe the genesis of these ores (Rose, 1976; 

Tourtelot, 1979; Byorlykke and Sangster, 1981; Gustafson 

and Williams, 1981; Nash and others, 1981; J\faynard, 

1983; Sverjensky, 1986, 1987; Coveney and Glascock, 

1989; Vaughan and others, 1989). In many of these models, 

metal transport is dominantly by some mechanistr involving inorganic complexes, whereas metal deposition is 

caused by epigenetic or indigenous organic matter (including micro-organisms). During the past 10 years, efforts 

have been initiated by a small number of inve<-tigators 

to study the importance of organic matter as a means of 

metal transport in ore fluids, in particular, Mi<-sissippi 

Valley-type (MVT) ore solutions (Giordano and Barnes, 

1981; Giordano, 1985; Drummond and Palme~, 1986; 

Kharaka and others, 1987; Hennet and others, 19~8; Gize 

and Barnes, 1989). Progress, however, has been slow in 

developing satisfactory ore fluid models that incluc~ metalOrganic Ligands and Metal-Organic Complexrrtg 31 
organic complexing. The principal reason for this slow 

progress can be attributed to a lack of information on (1) the 

chemical and physical constraints of ore-forming environments, especially pH and oxidation state, (2) the nature and 

concentration of organic ligands in ore-forming environments, and (3) the thermodynamic properties of pertinent 

metal-organic complexes. 

In this paper I present a brief status report on current 

knowledge about the role of metal-organic complexing in 

the genesis of MVT deposits and related shale-hosted 

deposits. Hopefully, this knowledge will encourage 

researchers in their efforts to evaluate the genetic role of 

metal-organic complexes in the formation of all basinrelated metal-rich deposits. First, I briefly discuss how 

organic ligands are produced in the diagenetic environment 

and what their observed concentrations are in modem 

sedimentary basin waters. Next, I comment on the availability of thermodynamic data sets for metal-organic complexes and I evaluate the importance of organic ligands as 

metal-transporting agents in several proposed MVT ore 

fluid models. Finally, I discuss the possible importance of 

organic ligands as metal-transporting agents in ore fluids for 

shale-hosted and red-bed-related deposits. 

ORGANIC LIGANDS 

The source of organic ligands in a basinal ore fluid 

can be directly linked to the nature and transformation of 

organic matter within the sedimentary basin. Many complex 

and simple interactions lead to diagenetic transformations of 

this organic matter (Tissot and Welte, 1984; Kharaka and 

others, 1985; Lundegard and Kharaka, 1990). Some of the 

more important diagenetic processes are presented on figure 

1. On this figure, the progressive diagenetic changes in solid 

organic matter (middle column) and the nature of dissolved 

organic material in the pore water (right column) are shown 

as a function of depth interval in which transformations are 

initiated. If basinal pore waters represent potential ore fluids 

that through time evolve toward specific ore fluids during 

diagenesis, then it is likely that organic acid ions, phenols, 

thiols, and organic sulfides (fig. 1, right column) are among 

the more important organic ligands in these evolving ore 

fluids. 

A rough correlation between sediment depth on figure 

1 and deposition temperature in table 1 provides a means of 

predicting which organic ligands should be expected in 

specific types of ore fluids. In table 1, the deposition 

temperature for a specific deposit type is probably similar to 

the maximum temperature of water-rock interaction for the 

corresponding evolving ore fluid. These pore waters, which 

probably have their source far from the site of deposition, 

scavenge organic ligands and metals from their source 

sediments as well as from rocks along the path of migration 

to the site of deposition. A potential ore fluid can migrate 

from or through the hotter parts of the basin. In both cases, 

32 Metalliferous Black Shales and Related Ore Deposits 
GENERATION AND DIAGENESIS OF KEROGEN 

Sediment depth Transformations in sediment Dissolved species 

Onset of transformations In pore water 

First few 

meters 

Biopolymers t Biochemical degradation 

Sugars, amino acids, less degraded 

lipids, lignin, and so on 

+ Po~condensaffon 

Sugars, amino acids, 

fulvic acids , 

humic acids 

First 1 O's 

of 

meters { 

10's to 100's { 

of meters 

500 { 

Humic and fulvic acids 

I Polycondensation 

t Elimination 

Humin 

I Polycondensation 

t Elimination 

Kerogen 

1 Early stage of 

+ kerogen degradation 

I 

Fulvic and humic acids, 

NH3 

Fulvic and humic acids, 

carboxylic acids 

carboxylic acids , 

phenols, thiols, sulfides, 

thiophenes, C02, H20, 

to hydrocarbons 

3,000 meters 

Kerogen + bitumen 

~ Hydrocarbon generation 

Figure 1. Formation and diagenesis of organic matter in sediments as a function of depth. 

the composition of dissolved organic matter in the ore fluid 

should be strongly influenced by reactions at the highest 

temperatures attained. For example, molecules of amino, 

humic, and fulvic acids (fig. 1) should be the dominant 

organic ligands in "cold" (less than about 50 °C) ore fluids 

(table 1) evolved at depths of less than about 1,000 m. 

Carboxylic acid ions, phenols, and organic sulfur species 

should be the dominant organic ligands produced, along 

with hydrocarbons and other products of kerogen degradation, in "hydrothermal" (greater than about 50 °C) ore 

fluids evolved from deep-basinal pore waters. 

Analyses of dissolved organic matter in subsurface 

waters confirm the above speculations. For example, fulvic 

and humic acids are the dominant organic constituents in 

surface waters and cold interstitial waters of shallow sediments. Lesser amounts of amino acids and carbohydrates 

are also found as dissolved constituents in these waters 

(Stumm and Morgan, 1981; Thurman, 1985). Because 

molecules of humic substances and amino acids form strong 

complexes with metals, they may contribute significantly to 

metal transport in cold ore solutions (sandstone uranium 

deposits, syngenetic metal-rich shales and possibly red-bed 

copper deposits); however, these ligands have a low thermal 

stability and are not likely to be important in ore fluids 

having temperatures much greater than 50 °C (Giordano, 

1985). 

Various carboxylic acid ions are also found in cold 

surface and subsurface waters where they always form a 

minor component of the dissolved organic matter. In deepbasinal pore waters, however, carboxylic acid ions are the 

dominant dissolved organic constituents (Surdam and 

others, 1984; Kharaka and others, 1985; Hanor and 

Workman, 1986; Fisher, 1987; MacGowan and Surdam, 

1988; Fisher and Boles, 1990). As shown in table 2, acetate 

generally dominates in these waters and is followed in level 

of concentration by longer chained aliphatic acid ions. 

Some deep-basinal waters contain high concent-ations of 

dicarboxylic acid ions, especially oxalate, malonate, and 

succinate (table 2). Dissolved phenolic compounc~ are also 

known to be present in deep sedimentary basin waters, but 

their concentrations are not well established (Kh'=~raka and 

others, 1985; Fisher and Boles, 1990). To my knowledge, 

thiols and other dissolved organic sulfur species have not 

been identified in deep formation waters. T'"'e above 

evidence suggests that acetate, oxalate, malonate, and succinate may be important organic ligands in certrrn hydrothermal basinal ore solutions. These acid ions form 

moderately strong metal-organic complexes and probably 

are at least moderately metastable under hydrothermal 

conditions. (Kharaka and others, 1983; Drumnond and 

Palmer, 1986; Lundegard and Kharaka, 1990). 

Organic Ligands and Metal-Organic Complexing 33 
Table 2. Dissolved organic ligands detected in sedimentary basin brines-aliphatic acid anions 

[NA indicates data not available, ND indicates not determined] 

Name of acid Concentration maxima Reservoir 

Common IUPAC (ppm) (molality) temp. ("C) 

Formic .................. Methanoic ....................................... 63 10-2·

86 91 1 

Acet.ic .. _. ................ Ethanoi~ ................................... } 0,000 0.17 NA 2 

Proptomc .............. Propanotc ................................... .4,400 0.06 88 1 

Butyric ................. Butanoic ....................................... 250 10-2

·

55 55 3 

Valeric .................. Pentanoic ...................................... 206 10-2·

69 55 3 

Oxalic .................. Ethanedioic .................................... 494 10 -

2

·

26 88 1 

Malonic ................ Propanedioic ................................ 2,540 0.025 101 1 

Succinic ................ Butancdioic ...................................... 63 10 -

3

·

30 98 4 

Glutaric ................. Pentancdioic .................................... 36 10-3·

52 98 4 

Adipic .................. Hexanedioic ....................................... 0.5 10-5

·

5 77 4 

Pimelic ................. Hcptanedioic ...................................... 0. 6 10-5.4 77 4 

None .................... Octanedioic ........................................ 5.0 10-4

·

5 98 4 

Azelaic ................. Nonanedioic ....................................... 6.0 10-4

·

5 98 4 

None .................... Decanedioic ....................................... 1.3 10-5

·

2 98 4 

Mcthylsuccinic ....... Methylbutanedioic ............................ NO ND 98 4 

None .................... 2-methylpcntanedioic ....................... ND ND 98 4 

~M~al~e~ic~·~··~··~··~·~··~··~··~·~··~-B~u~t~cn~c~d~io~i~c~··~··~·~··~··~··~··~·~··~··~··~··~·~··~··~··~·~··~··~··~··~2~6~----------l~0~--_· 1 ______ ~N~A~ ________ 2 

*1, MacGowan and Surdam (1988); 2, Surdam and others (1984); 3, Fisher (1987); 4, Kharaka and others (1985). 

THERMODYNAMIC DATA 

To evaluate the importance of a particular metalorganic complex in ore fluids and formation waters, the 

theoretically estimated concentration of that species in 

solution must be determined by calculation. Three types of 

information are required to perform such a calculation: 

(1) chemical and physical parameters of the solution and 

its surrounding geochemical environment, (2) stoichiometry 

of all possibly important aqueous and nonaqueous species, 

and (3) thermodynamic data for all possibly important 

aqueous complexes. The latter two categories will be 

discussed first, with specific reference to metal-organic 

complexes, and the first category will be considered in the 

next section. 

A large body of thermodynamic data is available in 

the form of stability constants at temperatures of about 25 

°C for metal-organic complexes involving the following 

ligands: acetate, oxalate, malonate, succinate, and amino 

acid ions (Martell and Smith, 1977, 1982). Approximate 

stability constants are also available for some humic and 

fulvic acid complexes for temperatures near 25 °C. These 

low-temperature data are sufficient to adequately model 

speciation in cold ore fluids if all other pertinent data and 

information are available. To accurately calculate speciation 

in hydrothermal fluids, thermodynamic data at the specified 

hydrothermal temperature are required. At present, hightemperature data are available for acetate complexes of 

some rock-forming and ore-forming metals (table 3). For 

34 Metalliferous Black Shales and Related Ore Deposits 

most other metal-organic complexes of interest, data are 

available only at temperatures near 25 °C (Martell and 

Smith 1977, 1982). The speciation models present~d in the 

next section were developed using high-temperature thermodynamic data for acetate complexes of Zn2

+, Fe2+, Pb2+, 

Na+, and Al3+; low-temperature data (about 25 °C) for 

acetate complexes of Ca2

+ and Mi+, oxalate co'llplexes, 

malonate complexes, succinate complexes, and catechol 

complexes; and available thermodynamic data on chloride, 

carbonate, sulfate, and hydroxide complexes. 

MISSISSIPPI VALLEY-TYPE 

ORE SOLUTIONS 

Concentrations of Ca, Mg, Na, Fe, AI, Pb, a,d Zn as 

acetate, oxalate, malonate, succinate, and cated'0l complexes have been calculated for three reconstructed MVT 

ore solutions at I 00 °C. The results for lead and zinc are 

shown in table 4. The three reconstructed (me del) ore 

solutions are described in terms of log ao2 and pH on figure 

2. In the model proposed by Anderson (1975), the ore fluid 

is oxidized and plots well above the sulfide-sulfat~~ boundary. It is slightly acid and contains 10-2 molal total sulfur, 

principally in the form of so/-, with reducei sulfur 

concentrations well below 1 o-5 molal. The ore solution 

proposed by Giordano and Barnes (1981) is redr~ed and 

plots well below the sulfide-sulfate boundary. It is slightly 

alkaline and contains 1 o-2 molal total sulfur, principally as 

bisulfide. In the model proposed by Sverjensky (19~4), the 
Table 3. Stability constants for selected metal-acetate complexes-Temperature range of experimental data 

Temperature 

Reaction range (°C) 1 References 

+ - H +Ac =HAc 25-50 Ellis (1963), Lown and others (1970), Fisher and Barnes (1972), Oscarmn 

and others (1988), Mesmer and others (1989). 

+ - Na +Ac =NaAc 18-310 Noyes (1907), Fisher and Barnes (1972), Oscarson and others (1988). 

2+ - + Ca +Ac =CaAc 25 Martell and Smith (1977, 1982). 

2+ - + Mg +Ac =MgAc 25 Martell and Smith (1977, 1982). 

2+ - + Fe +Ac =FeAc 

2+ - Fe +2Ac =FeAc2 

50-300 

50-300 

Palmer and Drummond (1988). 

Palmer and Drummond (1988). 

2+ - - Fe +3Ac =FeAc

3 250-300 Palmer and Drummond (1988). 

3+ - 2+ Al +Ac =AlAe 

3+ - + Al +2Ac =AlAc

2 

25-125 

75-150 

Drummond and others (1989). 

Drummond and others (1989). 

2+ - + Ph Ac =PbAc 25-85 Hennet and others (1988), Giordano (1989). 

2+ - Ph +2Ac =PbAc2 25-85 Hennet and others (198R), Giordano (1989). 

2+ - + Zn +Ac =ZnAc 25-300 

25-300 

Giordano and Drummond (unpublished data). 

2+ - Zn +2Ac =ZnAc2 Giordano and Dmmmond (unpublished data). 

2+ - - Zn +3Ac =ZnAc

3 

25-300 Giordano and Drummond (unpublished data). 

1 

25 °C data also cited by Martell and Smith (1977, 1982). 

ore solution is also reduced, with log 3.o2-pH conditions just 

below the sulfide-sulfate boundary. The solution is moderately acid and contains 10-5 molal total sulfur, principally as 

H2S. 

For the three ore-fluid models, several mineral 

saturation constraints were applied. These are listed in table 

5 together with the concentrations of organic ligands used in 

these models. The concentrations of acetate (0.15 molal), 

oxalate, malonate, and succinate represent the maximum 

values observed in basinal brines (table 2). The concentration of total catechol (0.01 molal) is an arbitrarily chosen 

value that is in the concentration range reported for oxalate, 

malonate, and succinate but is well below catechol solubility in water ( 4 molal, 25 °C). Although catechol has not 

been found in oil or gas field brines, Surdam and others 

( 1984) suggested that aluminum catechol complexes may be 

responsible for significant aluminum mobilization during 

diagenesis. In all three models, total chloride is approximately 3 molal and the total chloride to total acetate ratio is 

about 20 to 1. 

The results presented in table 4 shed light on several 

aspects of lead and zinc transport in the proposed rr0de1 ore 

fluids. If the minimum concentrations of lead and zinc 

required to form an ore deposit are 1-10 ppm (Barnes, 

1979), then in model 3 proposed by Giordano and Barnes 

( 1981) sufficient metal cannot be transported by any of the 

listed complexes. To a lesser extent this is the situation with 

model 2 (Sverjensky, 1984). In model 1 (Anderson, 1975), 

however, sufficient zinc and lead can be tra'lsported 

predominantly as chloride complexes. Note alsc that in 

Anderson's (1975) model (model 1) significant concentrations of lead and zinc are transported as acetate, oxalate, 

and malonate complexes. In model 2, chloride ccmplexes 

are also dominant, and acetate, oxalate, and malonate 

complexes account for the second largest fraction of lead 

and zinc. In model 3, bisulfide complexes are b:' far the 

dominant species, and all other complexes account for only 

insignificant amounts of metal in solution. 

In all three models, catechol is unable to transport 

significant amounts of lead and zinc. This follows from the 

Organic Ligands and Metal-Organic Complex~ng 35 
Table 4. Calculated concentrations of lead and zinc in proposed Mississippi Valley-type ore fluids 

[Metal concentrations in parts per million; the minimum concentration required to form an ore deposit is 1-10 ppm (Barnes, 1 <:79)] 

Modell 

Complex 

1 

Anderson (1975) 

Total lead ................................ .19.50 

Lead chloride ............................. 19. 0 0 

Lead hydroxide ............................ 0.23 

Lead bisulfide ............................. 1.6xl0-9 

Lead acetate ................................ 0.22 

Lead oxalate ............................... 0.014 

Lead malonate ............................. 0.014 

Lead succinate ............................. 7.2x1 0 -5 

Lead catechol.. ............................ 4.7x10 -7 

Total zinc ............................... l38.0 

Zinc chloride ........................... 13 5. 0 

Zinc hydroxide ............................ 1.1 

Zinc bisulfide ............................. 1.3x10-9 

Zinc acetate ................................ 0.44 

Zinc oxalate ............................... 0.28 

Zinc malonate ............................. 0.22 

Zinc succinate ............................. 3.8x1 0 

Zinc catechol.. ............................ 6.2x10 

l 

LS=lo·2 m, pH=5.7, loga0 =-50. 

2 

2

LS=1o-5 m, pH=4.5,loga0 =-52. 

2 

3

LS=to-2 m, pH=7.2,loga0 =-55. 

2 

-4 

-5 

law of mass action, which favors H+ in the competition for 

catechol ions within the given pH ranges of the ore fluids. 

The competition among cations for organic ligands is an 

important factor in controlling the speciation in these ore 

fluids and in all basinal waters. To illustrate the nature of 

this competition, speciation of Na, Ca, Mg, Fe, AI, Pb, and 

Zn with the ligands listed in table 5 was calculated for a 

model sedimentary basin brine at 100 °C and having a 

composition similar to the model MVT ore solution of 

Anderson ( 197 5). The mineral saturation constraints listed 

in table 5 were assumed in this calculation. The results are 

presented in tables 6 and 7. Because Anderson's ore 

solution (model 1, table 4) can account for sufficient 

transport of lead and zinc, it was chosen as a guide in 

constructing the model sedimentary basin brine. 

Furthermore, model 1 is similar to the oxidized ore fluids 

proposed by Rose (1976) and Sverjensky (1987) for 

sediment-hosted, copper-rich deposits (for example, red-bed 

copper deposits). 

36 Metalliferous Black Shales and Related Ore Deposits 

Model2 

2 

Sverjensky (1984) 

0.09 

0.09 

-4 l.lx10 

-5 4.9x10 

-4 8.3x1 0 

-5 7.9x10 

-5 9.3x10 

-7 7.6x10 

-11 1.6x10 

0.68 

0.68 

-4 5.4x10 

-5 4.1x10 

-3 6.0x10 

-3 1.4x10 

-3 1.1xl0 

-6 2.0x10 

-9 2.0x10 

Model3 

3 

Giordano and Barnes (1981) 

-3 2.1x10 

-8 1.4xl0 

-9 5.4xl0 

-3 2.1x10 

2.8xlo- 10 

-11 2.0x10 

-11 

1.5x10 

-14 6.2x10 

-13 3.3x 10 

-3 3.lxl0 

-7 l.OxlO 

-8 2.5xl0 

-3 3.lx10 

-10 4.7xl0 

-10 

4.6x10 

-10 

2.2x10 

-13 3.6x1 0 

-1 1 4.6x10 

Calculated chloride and organic ligand spe.ciation for 

the model sedimentary basin brine is given in table 6 as 

percent of ligand bound in the indicated species o .. complex. 

In this oxidized and slightly acid solution, the ligands 

acetate, oxalate, malonate, and succinate are p"'esent primarily as free ions, singly protonated species, and complexes ofNa, Ca, and Mg. Although carboxylate complexes 

of Pb, Zn, AI, and Fe have a greater thermodynamic stability 

than carboxylate complexes of ~a, Mg, and Ca, t'le free ion 

activities of the former group of metals are too lo'v to allow 

significant competition with the weakly compl ~xing, but 

more abundant, ions of Na, Mg, and Ca. Catechol, which 

contains one carboxyl group and a phenolic group, forms 

very stable metal-organic complexes. At the pH of the 

model brine, however, the proton is the dominant cation 

competitor, and almost 100 percent of the catechol ligand is 

in the form of the doubly protonated species. Because of the 

low activity of ionized catechol, only small allounts of 

metal-catechol complexes are formed. 
Table 5. Speciation of metal-organic complexes in 

sedimentary basin brines 

MODEL PARAMETERS A.'ol) CONSlRAJNTS 

Galena saturation 

Sphalerite saturation 

INORGA.t~C UGANDS 

Chloride 2.5-3.0 molal 

Carbonate 

Sulfate 

Sulfide 

Hydroxide 

Calcite saturation 

Quartz saturation 

Potassium feldspar saturation 

ORGAl~C UGMros 

Acetate 0.1-0.15 molal 

Oxalate 0.005 molal 

Malonate 0.025 molal 

Succinate 0.0005 molal 

Catechol 0.01 molal 

Calculated metal speciation for the model brine is 

given in table 7 as percent of metal bound in the indicated 

species. Although presented differently, the results in this 

table for lead and zinc are similar to the results for the 

model of Anderson (1975) given in table 4; more than 90 

percent of the lead and zinc is in chloride complexes, and 

only 1-3 percent of these metals is bound in carboxylate 

complexes. Sodium is present primarily as the free ion (75 

percent), the chloride complex accounts for 23 percent, and 

only 2 percent is bound in carboxylate complexes. Calcium 

and magnesium are also present primarily as free ions or in 

chloride complexes, but approximately 10 percent of each 

of these metals is present as an acetate complex, and 

N 

0 

0 60 

0' 

0 

65 

Giordano and Barnes (1981) 

Figure 2. Oxidation state and pH of model Mississippi 

Valley-type ore fluids at 100 oc. 

approximately 4 percent is bound in other carboxylate 

complexes. Iron is present primarily as the free ion (22 

percent), in chloride complexes (46.5 percent), and 

hydroxide complexes (18 percent). Similar to calcium and 

magnesium, about 10 percent of the iron is irr acetate 

complexes and about 4 percent is bound in other carboxylate species. Of all the metals considered in this model, 

aluminum is the only one that is present in solution 

predominantly as organic complexes (53 percent). Of the 

total dissolved aluminum, 25 percent and 47 percent are 

accounted for by complexes of acetate and hydroly~ed 

aluminum species, respectively. Note that 10 percent of the 

aluminum is bound in catechol complexes. Aluminum 

forms very stable catechol complexes and apparently 

competes moderately well with protons at near ne' 1tral pH. 

CONCLUSIONS 

The calculated speciations presented in tal:les 4, 6, 

and 7 should be considered with caution. More reliable 

estimates of speciation can be made when additio"'al hightemperature thermodynamic data for metal-organic complexes and additional information regarding pertinent 

organic ligands and their concentrations in basinal waters 

are available. Nevertheless, from the results presented in 

these tables, some important inferences can be mad~ regarding metal transport by organic complexes in sedimentary 

basin brines and related ore fluids. The results pre~~nted in 

table 4 clearly show that in the model ore fluids proposed by 

Giordano and Barnes (1981) and Sverjensky (1984) 

significant amounts of zinc and lead cannot be mobilized as 

organic complexes involving the ligands acetate, oxalate, 

malonate, succinate, and catechol; however, other zinc- and 

lead-organic complexes (organic sulfur complexes) may be 

important in ore fluids having such model ch~mistries 

(Giordano, 1985; Gize and Barnes, 1989). It is alsC' possible 

that these model fluids better describe spent r.tJ:VT ore 

solutions at or close to the site of deposition ra+her than 

fluids transporting metals to the site of depositior. 

In the alternative oxidized ore fluid proposed by 

Anderson (1975) (model 1, table 4) and the similar brine 

model described in tables 6 and 7, significant quzntities of 

dissolved metal can be accounted for by complexes of the 

ligands acetate, oxalate, malonate, succinate, and catechol. 

Both models are similar in oxidation state, pH, tenperature 

and major ion chemistry. Total reduced sulfur is kw (about 

10-9 molal), pH slightly acid (about 5.5), and total chloride 

to organic ligand ratios high (Cl/Ac=20, Cl/Ox=600, 

Cl/Mal=120, C1/Suc=6,000, and Cl/Cat=300). Irr terms of 

percent of metal bound in metal-organic comphxes, the 

order of importance for the five organic ligands i~ acetate, 

malonate, oxalate, succinate, and catechol. In the model 

brine solution, 53 percent of the aluminum is mobilized 

in the form of metal-organic complexes. Metr1-organic 

Organic Ligands and Metal-Organic Comple:ving 37 
w 

= 

i 

~ 

a 

c 

"' 

ii' = 

n 

:11:" 

VI 

::r 

!!.. 

~ 

Ill 

= 0.. 

:;:.:, 

~ 

;-

[ 

0 

.. 

~ 

0 

~ 

] 

a: 

Table 6. Calculated ligand speciation in model sedimentary basin brine having composition similar to ore fluid proposed by Anderson 

(1975) 1 

[NC indicates not calculated] 

Total Percent ligand bound in indicated SRecies 

Ligand molality l Hl H l Na Ca Mg Pb Zn 

2 

Chlorite ........... 2.85 76.27 NC NC 14.73 5.00 4.00 <0.01 <0.01 

Acetate ............ 0.15 36.84 5.88 NC 20.71 29.22 7.19 <0.01 <0.01 

Oxalate ............ 0.005 11.76 0.12 <0.01 NC 59.29 30.64 0.02 0.17 

Malonate .......... 0.025 21.89 6.07 <0.01 31.95 24.45 15.46 <0.01 0.02 

Succinate .......... 0.0005 37.92 9.92 0.27 23.65 23.11 5.13 <0.01 <0.01 

Catechol .......... 0.01 <0.01 0.02 99.98 NC <0.01 <0.01 <0.01 <0.01 

lT=lOO °C, I:sulfide=l.7xl0-9 m, I:sulfate=0.055 m, I:carbonate=7.2xlo-3 m, pH=5.5. 

Fe 

<0.01 

<0.14 

0.19 

0.16 

<0 01 

<0.01 

Table 7. Calculated metal speciation in model sedimentary basin brine with composition similar to ore fluid proposed by Anderson (1975) 

[Model parameters: T=lOO °C, I:sulfide=l.7xl0-9, I:sulfate=0.055 m, pH=5.5, I:carbonate=7.2xto-3 m, I:chloride=2.85 m, I:acetate=0.15 m, I:oxalate=0.005 m, 

Isussinate=0.0005 m, I:malonate=0.025 m, Icatechol=O.Ol m. ~C indicates not calculated] 

Percent metal bound in indicated species complex 

Total Free 

Metal (eem) ion Chloride H}:droxide Acetate Oxalate Malonate Sussinate Catechol 

Na ........... .4.84x104 74.98 23.13 <0.01 1.50 NC 0.38 0.01 NC 

Ca ............ l.87x104 72.31 16.17 <0.01 9.52 0.62 1.35 0.02 <0.01 

Mg ........... 2.24x1o3 50.02 32.28 <0.01 11.72 1.69 4.26 0.03 <0.01 

Pb ............ 2.79x1o1 0.17 96.52 0.82 2.32 0.08 0.08 <0.01 0.01 

Zn ............ 1.93x102 0.27 98.38 0.55 0.56 0.23 <0.01 <0.01 <0.01 

Fe ............. 8.57x1 o1 22.22 46.44 18.07 9.92 0.62 2.73 <0.01 <0.01 

Al.. ........... 7.~8xlo-4 0.()() NC 46.07 25.3q 17.77 l'I.Tf"" .1 <'-' N~"" '-' I) .1)0 

AI 

NC 

<0.01 

<0.01 

NC 

NC 

<0.01 
complexes account for 17 percent, 13 percent, and 11 

percent of the magnesium, iron, and calcium, respectively, 

in solution but only 2.5 percent of the lead, 1.5 percent of 

the sodium, and 0.8 percent of the zinc. The bulk of the lead 

and zinc in solution (>96 percent) is solubilized in the form 

of chloride complexes. These results are in agreement with 

results of Lundegard and Kharaka ( 1990), which show that 

metal-organic complexes are not the dominant form of lead 

and zinc in typical sedimentary basin brines, but that iron, 

calcium, and possibly aluminum do form important metalorganic complexes in these waters. 

If the oxidized brine model (tables 6 and 7) is 

modified by increasing each of the organic ligand concentrations by a factor of two or three, a significant shift in 

favor of organic complexes would be observed. Unpublished data of Giordano and Drummond show for zinc that 

acetate complexing is dominant relative to chloride complexing in solutions having [chloride ion]/[acetate ion] 

ratios of less than about 10 at temperatures from 25 to 

300 °C. Evidence presented by Lundegard and Kharaka 

( 1990) from brine analyses and theoretical models (which 

simulate the generation and destruction of organic acids in 

basinal waters) suggests that concentrations two to three 

times those given in table 2 are not unreasonable for 

primary organic acid concentrations. Here, primary concentration is defined as the concentration that exists before 

significant destruction of the organic acid takes place 

(Lundegard and Kharaka, 1990). Basinal fluids having such 

high ligand concentrations (low chloride/organic ligand 

ratios) are rare but may exist as pore water in metal-rich 

black shales or petroleum source rocks (Lundegard and 

Kharaka, 1990). Extraction of metals into these organic-rich 

pore waters and subsequent expulsion of the metal-rich 

fluids into more porous rocks during the evolution of 

sedimentary basins may be the initial stage in the generation 

of metal-rich basinal brines and related ore fluids. 

As mentioned above, the oxidized brine model (tables 

6 and 7) is similar in chemistry to the MVT ore solution 

model of Anderson ( 197 5) and to the brines recommended 

by Rose (1976) and Sverjensky (1987) as possible ore fluids 

for red-bed-related copper deposits in shale. Similar brines 

can now be linked to deposits that have a strong syngenetic 

character. For example, there is a sufficient body of 

evidence to infer that most of the lead, zinc, and copper in 

the highest grade zones of the Kupferschiefer was 

introduced during late diagenesis by oxidized metal-rich 

brines at temperatures near 100 °C (Jowett, 1986; Jowett 

and others, 1987; Vaughan and others, 1989). And recently, 

Coveney and others ( 1987) and Coveney and Glascock 

(1989) proposed a genetic link between the mineralization 

of certain Pennsylvanian black shales of the U.S. Midcontinent and basinal brines, possibly MVT ore fluids. This 

geologic evidence linking basinal brines to syngenetic 

metal-rich shales and the well-known relationshir between 

basinal brines and classic red-bed copper deposits provide 

sufficient grounds for the construction of prelimi ,ary geochemical models of epigenetic processes related to metalrich black shale deposits. 

The basinal brine model presented in this paper 

(tables 6 and 7) shows that metal-organic complexes may be 

important in transporting lead, zinc, and other metals in 

warm, oxidized ore fluids similar to those pro'Josed by 

Sverjensky (1987) for red-bed-related copper-rich shales. It 

is hoped that these results will encourage investigatiors to 

incorporate metal-organic complexing (including complexes of Cu, Ni, V, Mo, and platinum-group m~tals) into 

genetic models for shale-hosted deposits. Although the ore 

solution models described in this study are based on a less 

than ideal thermodynamic data base, the principal 

deficiency is clearly the lack of well-constrained geochemical parameters for Mississippi Valley-type oreforming systems. Efforts to produce reliable ore transport 

and deposition models for sediment-hosted deposits must 

focus on the problems of well-constrained geochemical 

parameters and the procurement -of comprehensive and 

reliable thermodynamic data. 

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Organic Ligands and Metal-Organic Complrxing 39 
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40 Metalliferous Black Shales and Related Ore Deposits 

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Organic Ligands and Metal-Organic Complexi"~ 41 
When is a Metalliferous Black Shale 

Not a Black Shale? 

By Holly L.O. Huyck 1 

Abstract 

Black shales are linked to cycling of carbon, nitrogen, 

phosphorous, sulfur, oxygen, and heavy metals such as iron, 

molybdenum, vanadium, and uranium. As a result, they are 

potentially both mineral and energy resources, and environmental hazards (for example, uranium-rich shales used for 

roofing in Scandanavia). The importance of such shales 

prompted the formation of the International Geological 

Correlation Program (IGCP) Project 254, Metalliferous Black 

Shales and Related Ore Deposits, in 1987. Yet, based upon 

discussion at workshops and symposia of IGCP 254, definitions of shale, black shale, and metalliferous black shale either 

elude us or require revision. The proposed definition for a 

"black shale" is "a dark-colored (gray or black), fine-grained 

(silt sized or finer), laminated sedimentary rock that generally 

is argillaceous and contains appreciable carbon (>0.5 wt. 

percent)." This is an inclusive definition, and the term should 

be used with various modifiers that characterize the specific 

black shale. The traditional definition of metalliferous black 

shale, based on the classic study of Vine and Tourtelot (1970), 

requires revision in order to encompass more elements and to 

account for improved analytical techniques. The proposed 

definition of a "metalliferous black shale" is "a black shale that 

is enriched in any given metal by a factor of 2X (except for 

beryllium, cobalt, molybdenum, and uranium, for which 1 X is 

sufficient) relative to the U.S. Geological Survey Standard 

SD0-1." 

Characteristics that should be included in the basic 

description of a black shale include location, stratigraphic 

position, scale of variation, regional distribution, thickness, 

sedimentary facies, paleontology, depositional environment, 

petrography, texture, fabric, color, mineralogy, weight percent 

organic carbon, weight percent carbonate carbon, weight 

percent sulfide sulfur, degree of pyritization (DOP), and type 

and maturity of organic material. Without describing these 

characteristics, we risk comparing the sedimentary equivalents 

of apples and oranges in our geochemical, isotopic, and other 

studies. 

1

Department of Geology. University of Cincinnati, Cincinnati, 

Ohio 45221. 

42 Metalliferous Black Shales and Related Ore Deposits 

INTRODUCTION 

In 1986, the editors of "Biogeochemistry of black 

shales" (Degens and others, 1986, p. IX) wrote: 

"A great variety of rocks are designated. as black 

shales. Their composition[s] and origins difcer greatly. 

For instance, they can be bituminous, phosphatic, 

carbonate-free or -rich, high or low in trr~e metals, 

sulfidic to a point of even being considere1 ore, and 

sometimes surprisingly low in carbon when c~-:lmpared to 

the average shale. With respect to [the] envi~onment of 

deposition, a black shale can be of freshwate~, brackish, 

marine or hypersaline origin, in other words, I:' lack shales 

can virtually be found in all aquatic habitats. They may 

contain abundant macro- and microfossils, or may be 

fossil-free. Black shales may be laid down in the shallow 

epicontinental sea, along continental margins, or in deep 

oceans and lakes. They can be formed in situ, or be 

allochthonous in nature. Their organic matter can be 

mature or immature***'Why do we group such a diverse 

group of sediments together which obviously only share 

one property, namely that of being black?' 

The answer is: all black shales are linked directly or 

indirectly to high organic activity and the cycling of 

biogeochemical elements, most notably carbon, nitrogen, 

phosphorus, sulfur, oxygen plus heavy metds such as 

iron, molybdenum, vanadium, and uranium." 

Because the term black shale includes such a wide 

variety of sediments and sedimentary rocks it has been 

difficult to find a definition that is inclusive yet meaningful. 

The definitions proposed in this paper are based on verbal 

and written discussions of definitions previously presented 

at various times by the author to members of the U.S. 

Working Group of the International Geological Correlation 

Program (IGCP) Project 254. 

The purpose and structure of this paper a~e twofold. 

First, previous and proposed definitions of blad~ shale and 

metalliferous black shale are briefly reviewed. Se~ond, a list 

of the minimum number of characterizations of a shale 

needed in order to compare it to other shales is presented. A 

very inclusive definition of black shale is preferred, with a 
Table 1. Mudrocks as classified by Spears (1980) 

Percent 

quartz 

<40 

30-40 

20-30 

10-20 

<10 

Fissile Nonfissile 

Flaggy siltstone ......... Massive siltstone. 

Very coarse shale ........ Very coarse mudstone. 

Coarse shale .............. Coarse mudstone. 

Fine shale ................. Fine mudstone. 

Very fine shale ........... Very fme mudstone. 

Degens and others (1986) have stated, the term black shale 

covers a multitude of variations, providing the potential for 

comparing the sedimentary equivalents of apples, oranges, 

and rutabagas. 

DEFINITION OF SHALE 

Based upon historical usage, "shale" has "the meaning of the 'general class of fine-grained rocks'" (Tourtelot, 

1960, p. 342). As Spears (1980) noted, a more appropriate 

term may be either "mudrock" or "mudstone" because 

neither implies any laminations or fissility. The author 

prefers to follow tradition and to use the term shale. 

Spears (1980, p. 127) defined a shale as "a fissile or 

laminated [fine-grained] rock." He classified the "mudrocks" in his study by presence or lack of fissility and by 

percentage of quartz (table 1). In the Coal Measures that he 

has studied, quartz is the major clastic (silt sized) component; feldspar is negligible, and total [carbonates + 

sulfides+ organic carbon] are less than 10 percent. Percent 

quartz may correlate with the silt-sized fraction in Spears' 

rocks but not necessarily in rocks containing significant 

quantities of feldspar.-

Potter and others ( 1980, p. 13) defined shale as a 

"fine-grained***sediment*** that contain[s] 50 percent or 

more of terrigenous, generally argillaceous, clastic components less than 0.062 mm" in equivalent spherical 

diameter. This definition is useful because it is easy to 

understand. Unlike the definition of Spears, it includes both 

fissile and nonfissile rocks. Their classification of shale is 

based on laminations, grain size, and degree of induration 

(table 2). Admittedly, grain-size determinations of indurated 

sedimentary rocks are difficult and qualitative. G. Desborough (U.S. Geological Survey, written commun., 1989) 

noted that many clay minerals and feldspar are commonly 

authigenic, and thus grains may be neither terrigenous nor 

clastic. If the 0.062-mm size cutoff is used for all rock 

constituents and "terrigenous" is replaced with "nonchemical," perhaps such objections can be averted. 

In light of the above discussion, the following definition for shale is proposed. A shale is a fine-grained, 

nonchemical sediment that contains 50 percent or more 

particles less than 0.062-mm equivalent spherical diameter 

in size. 

DEFINITION OF BLACK SHALE 

A similar problem occurs for defining black shale. 

For example, Arthur (1979, as quoted in Wapks, 1983, 

p. 963) used "black shale" to mean "***relatively organicrich (i.e. >0.5 wt. percent corg), dark-colored (dark gray, 

greenish black, and black) mudstone and marlstone which 

may or may not be 'shale' in the classical sense." 

An arbitrary lower limit can be set for weight percent 

of organic carbon in black shales. Arthur ( 1979) S'lggested 

0.5 percent, M. Zentilli (Dalhousie University, oral commun., 1989) and M. Graves (Cuesta Research Ltd., oral 

commun., 1989) 0.6 percent, Brumsack (1980, as ouoted in 

Waples, 1983) and M. Lewan (Amoco, oral C'lmmun., 

1990) 1.0 percent, and Kukal (1988) 1.5-2.0 percent. 

Analyses of Devonian shales in the Appalachian b"~sin (fig. 

1) indicate a break at 1.0 percent organic carbon. Stribmy 

and Urban (1989) and Urban and Stribmy (1989), in their 

classification of the "black shale series," sepa~ated > 1 

percent and <1 percent organic carbon and induced black 

shale in the > 1 percent organic carbon portion (fig. 2). Bates 

and Jackson (1987) used 5 percent organic carbo, for the 

minimum in black shales; however, the mediar for the 

"black shale" samples of Vine and Tourtelot (1970) is 3.2 

percent, and samples containing as little as 0.4- percent 

(Nonesuch Shale) are included. 

A strong argument may be made to place the lower 

limit at 1.0 percent organic carbon. The organi~ carbon 

content of "average shale" has been quoted as 0.65 percent 

(after Green, 1959, as quoted in Vine and Tourteht, 1970, 

table 3, p. 261), 0.8 percent (Potter and others, 1S'ry0, table 

1.8, p. 51), and 2.1 percent (Degens, 1965, p. 202)- The last 

average, in particular, may reflect a large number of shales 

sampled from petroleum-bearing basins. Although the 

minimum amount of organic carbon necessary to produce 

hydrocarbons is approximately 0.5 percent (Potter and 

others, 1980), the minimum needed to be an effective 

hydrocarbon source rock is approximately 2.4 percent 

(Lewan, 1987). 

Problems exist with setting an arbitrary lo·ver limit 

for organic carbon content. For example, if an arbit-ary limit 

of 1.0 percent organic carbon is set for an immature shale, 

what should be the limit for a thermally matu~e shale? 

Hydrocarbons may have moved in or out, depending upon 

the thermal maturity of the shale. F. Poole (U.S. G~ological 

Survey, oral commun., 1989) pointed out that thermally 

mature shales may contain only 0.1-0.3 percen• organic 

carbon, much less than their original content. Raiswell and 

Berner (1987) charted a significant loss of organ:~ carbon 

(as much as 40-60 percent) in normal marine shales as 

vitrinite reflectance increases, and Baker and Claypool 

(1970) demonstrated the loss of organic carbon during 

incipient metamorphism. Additionally, a "black" shale may 

contain less organic matter than a dark-gray shale 

(R. Schultz, University of Cincinnati, oral commu"'., 1990). 

Metalliferous Black Shale 43 
Table 2. Classification of shale (more than 50 percent grains less than 0.062 mm) according to Potter and 

others (1 980) 

Percentage 

clay-size constituents .............. 0-3 2 33-65 66-100 

Field adjective ....................... Gritty Loamy Fat or slick 

NO~TJNDURA1ED 

Beds (greater than 10 mm) ......... Bedded silt 

Laminae (less than 10 mm) ........ Laminated silt 

Bedded mud 

Laminated mud 

Bedded clayrnud 

Laminated clayrnrri 

Beds (greater than 10 mm) ......... Bedded siltstone Mudstone Claystone 

Laminae (less than 10 mm) ........ Laminatcd siltstone Mudshale Clayshale 

MET AMORPIIOSED 

Degree ......................... Low ......................... Quartz argillite ........................ Argillite 

of Quartz slate ............................ Slate 

metamorphism ............... High ................................. Phyllite and (or) mica schist 

Gray I Dk. Gray I Black---. 

120 -

C/) 

w 

..J 100 -- a.. 

~ 

- - <( 

C/) 80 

u. 

0 - a: 60 

w 

m 

~ 40 - :::> ~ 

- r-- ~ - z 

20 - ~ 

-

f n I l-r- 0 I I 

1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 >10 

PERCENT ORGANIC CARBON 

Figure 1. Weight percent organic carbon in Devonian shale samples (577) from the Appalachian Basin. From 

unpublished data of j.B. Maynard (University of Cincinnati, written commun., 1989). 

The use of color as a definitive characteristic is 

untenable because even with color charts, gray to one 

person is black to another. Kukal (1988) noted that, 

although organic carbon content is the major factor 

influencing color, finely disseminated iron sulfide or 

manganese oxide minerals may also color the shale. In the 

Black Sea, recent deposits are deep green and brown 

(Kukal, 1988). Conversely, when shales are exposed, 

44 Metalliferous Black Shales and Related Ore Deposits 

weathered, or dehydrated, they may tum gray, green or 

brown (for example, the Flowerpot Shale, host ro~k for the 

Creta copper shale deposit, Oklahoma). 

An arbitrary lower limit of organic carbon content, 

which varies with thermal maturity, is prefera1:1e. If the 

IGCP 254 group can find other, less transitory sig,atures of 

original organic content, then these could be incorporated. 

In their absence, a relatively low cutoff is recommended, 
Q 

c 

Q 

> 1 PERCENT 

Corg 

<1 PERCENT 

Corg 

Figure 2. Classification and nomenclature of fine-grained 

sedimentary rocks associated in the "black shale series" of 

Stribrny and Urban (1989) and Urban and Stribrny (1989). 

Apexes are quartz (Q), phyllosilicates (P), and carbonates 

plus remaining minerals (C). Normative mineral compositions (Q+P+C=1 00) are plotted in the upper triangle if 

organic carbon (C0 ) is greater than 1 percent and in the 

lower triangle if it is1ess than 1 percent. Normative minerals 

are based on weight percentages of different elements or 

oxides using chemical analyses of samples. Classification fields: 1, organic-carbon-rich lydite; 2, siliceous black 

shale; 3, carbonatic-siliceous black shale; 4, black shale; 

5, argillaceous-siliceous black shale; 6, organic-carbon-rich 

carbonate rock; 7, carbonatic black shale; 8, carbonaticargillaceous black shale; 9, argillaceous black shale; 

10, organic-carbon-rich pelite; 11, lydite; 12, siliceous shale; 

13, carbonatic-siliceous shale; 14, shale; 15, argillaceoussiliceous shale; 16, carbonate rock; 17, carbonatic shale; 

18, carbonatic-argillaceous shale; 19, argillaceous shale; 

20, pelite. 

such as 0.5 or 0.6 percent organic carbon. The resulting 

definition includes most documented "black shale" samples; 

other modifiers can be added for characterization (see later 

discussion.) 

Including the term "laminated" in the definition of 

black shale further delimits the minimum organic carbon 

content at the time of sediment deposition. Pre:\ence of 

laminations, at least in Phanerozoic shales, requires a lack 

of significant bioturbation and so indicates conditions too 

hostile to support a burrowing fauna. Such co'lditions, 

whether due to insufficient oxygen in the bottom water, 

excess salinity, or other factors, promote presen·ation of 

organic matter. Although burrows may be present, they are 

minor enough to limit disruption of the fabric to =:;; 2 on the 

ichnofabric scale as defined by Droser and Bottjer ( 1986). 

In light of the above comments, a definition for black 

shale is proposed, based on discussion among U.S. Working 

Group IGCP 254 members: 

A black shale is a dark-colored (gray or black), 

fine-grained (silt sized or finer), laminated sedimentary 

rock that generally is argillaceous and contains appreciable 

organic carbon(> 0.5 weight percent). 

This inclusive definition can be used with a variety of 

modifiers to further specify the rock type being d:.;;cussed. 

The definition modifies the general definition of sbde used 

earlier in this paper because shales containing 4(' percent 

organic carbon (for example, within the New Albany Shale) 

may contain less than 50 percent particles of I ~ss than 

0.062-mm equivalent spherical diameter. 

DEFINITION OF A METALLIFEROUS 

BLACK SHALE 

The classic definition of metalliferous black shales is 

that proposed by Vine and Tourtelot (1970, p. 253). "A 

black shale is defined as metal-rich if any minor ekment [of 

21 chosen] occurs in excess of the 90th perc~~ntile as 

determined from the sum of the percent frequency distribution of elements in the 20 sets of [779] black shale 

samples." This landmark effort provided a commcnly used 

definition for subsequent research. Since it wr" made, 

however, analytical techniques have improved sign;ficantly. 

In addition, other elements, such as the rare-earth ~lements, 

gold, phosphorous, and sulfur, are now elements of interest. 

These can be considered minor relative to the qu~stion of 

whether the sample set is appropriate; some of the black 

shales in the study of Vine and Tourtelot do not fit the 

definition recommended here. 

A second approach, suggested by M. Zentilli and M. 

Graves on the U.S. Working Group 1989 IGCP 254 field 

trip, is to define a black shale as metalliferous if any metal 

content exceeds two times the average continert.al crust 

composition. The required multiple exceeding this number 

can be readjusted. The main question is whe+her this 

approach is preferred. The approach has the advrqtage of 

not depending on a particular sample set or on rnalytical 

techniques at a particular time. Also, the nu'llber of 

elements included is larger than the 21 elements of Vine and 

Tourtelot. 

Metalliferous Black Shale 45 
Table 3. Abundances of clements (in parts per million) 

in black shale and metal-rich black shale and in 

average continental crust 

[Elemental values in parts per million] 

Black shale 

mean valuel 

Ti.. ........... 2,000 

Mn .............. 150 

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

B .................. so 

Ba .............. .300 

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

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

Cr ................ 100 

Cu ................ 70 

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

La ................. 3D 

Mo ............... 10 

Ni ................. so 

Pb ................ 20 

Sc ................. 10 

Sr ................ 200 

u .................. -2 

v ................. 1so 

Y .................. 30 

Zn ............. <300 

2'.r ••.•.••••••••..•• 70 

lvine and Tourtelot (1970). 

2Krauskopf (1979). 

3craig and others (1988). 

Metal-rich 

black shale 1 

7,000 

1,000 

7 

200 

1,000 

3 

30 

700 

200 

50 

70 

200 

300 

100 

30 

1,500 

30 

1,000 

70 

1,500 

200 

Average 

continental 

crust2•

3 

45,700 

4950 

50.07 

10 

425 

42.8 

425 

100 

55 

15 

(35) 

51.5 

75 

12.5 

(20) 

(375) 

2.7 

135 

(35) 

70 

4(165) 

4Crustal abundance is Vine and Tourtelot (1970) metal-rich 

black shale. 

5crustal abundance is much less than Vine and Tourtelot (1970) 

mean black shale. 

An example of what would be considered a metalliferous black shale in these first two cases is shown in table 

3. Note that the mean values are quite similar for the two 

groups except forTi, Mn, Be, Co, Zr (where crustal mean 

equals Vine and Tourtelot's "metal-rich," or "metalliferous") and Ag and Mo (where the crustal mean is at least six 

times less than Vine and Tourtelot's mean). If2X of average 

continental crust is used, the definitions will be similar. 

A third approach, suggested by J.S. Leventhal (U.S. 

Geological Survey, oral commun., 1989), is to base a 

definition for metalliferous shale on an arbitrary total of 

various elements. If each component is expressed in parts 

per million, then a metalliferous shale would contain: 

[(V+Cr+Co+Ni+Cu+Zn+Mo+Ag+Cd+Pb+U) 

+(As+Se+Sb+ Tl)+(Ba+Mn+REE+Zr)/5 

+(Corganic +S+Fe }/1 ,000]> 1,000 

Again, the specifics of the numbers are not as 

important as the general format. Such a definition is quite 

46 Metalliferous Black Shales and Related Ore Deposits 

arbitrary, yet is independent of the specific nature of any 

one data set. It invokes a slightly different phik~ophy by 

focusing on the sum total of a variety of elements, instead of 

any one, similar to the idea of co-products instea1 of main 

product versus byproduct. It is more restricted than the 

second approach in that it uses specific elements. Leventhal 

suggested this as a possible format but is not V'edded to 

the specific numbers. (I would prefer to delete the 

(Corganic+S+Fe) term because, although these ele~ents are 

important for constraining the environment of d ~position, 

they add little information about economic metal content.) 

At the 1989 U.S. Working Group meeting of IGCP 

254, an alternative definition was proposed that uses twice 

the metal content of the North American Shale Composite 

(NASC), rather than the average continental crust, as a basis 

for defining metalliferous black shale. Initially, this 

approach presented several advantages. The NASC has been 

analyzed by more quantitative techniques (Gromet and 

others, 1984; Taylor and McLennan, 1988) than have the 

samples of Vine and Tourtelot (1970), and it in~ludes 28 

trace and rare-earth elements. Comparison to NASC is 

preferable to an average continental crust, which is vaguely 

defined. Allowing one metal to define a black shale as 

metalliferous permits seeking significant anomal: ~s rather 

than looking for a slightly elevated content cf several 

metals. (Note that "metal," if used to mean transiti"ln metals 

and lanthanides, would exclude elements in the first two 

columns of the periodic table. Thus, Rb, Sr, Ba, and Cs 

could not be used to define a shale as metallifercrJs.) 

In subsequent efforts to compile analyse~ for the 

NASC, I discovered a number of problems with using it as 

the standard. First, important elements are missing. For 

example, Au, Ag, Mo, Pb, and Zn were not analyzed. 

Because these elements are important to many inv~stigators, 

the NASC is not a particularly useful standard. S{'r;ond, the 

NASC is a composite of 40 samples, not all from North 

America, and 15 of which are not located at all (Gromet and 

others, 1984 ). Third, no significant descriptions of the 

shales are available, so one has no idea whether even one of 

the shales is a black shale. Additionally, Gromet znd others 

(1984) noted a significant variability problem in tl'~ NASC. 

Other published shale composites, the Post-Archean 

Australian Shale (PAAS), the European Shale (ES), and the 

Marine Sciences Group Black-Shale Composite (MSG-: 

BSC) (Gromet and others, 1984; Quinby-Hunt and others, 

1989; Taylor and McLennon, 1988), suffer from a similar 

lack of elements (see table 5). Thus, search for ano~her shale 

standard commenced. 

Following discussions with Richard Grauch~ leader of 

the U.S. Working Group, and with Joel Leventhal, I propose 

replacing the NASC with the U.S. Geologiczl Survey 

standard SD0-1. This is the "USGS Devonian Otio Shale" 

(from Kentucky) that was discussed in the May 1988 
"Friends of Black Shales" newsletter (R.I. Grauch, written 

commun., 1988) and for which initial analyses were compiled by Belinda Arbogast. There are several advantages to 

using this standard. This sample is well located, both 

geographically and stratigraphically. It has been analyzed 

by approximately 30 laboratories around the world, is 

chemically well characterized, and has confidence limits for 

each element (table 4). SD0-1 also qualifies as a black 

shale under the definition given above. One disadvantage is 

that one sample is by definition not an "average" shale. (A 

brief description of SD0-1 characteristics is given later.) 

The analyses of SD0-1, shown in table 4, have been 

published in Geostandards Newsletter (Kane and others, 

1990). The varying confidence limits for individual elements-Recommended, Average, and Range-reflect 

decreasing confidence in reported values. For elements 

having only reported ranges, a midpoint of the range has 

been arbitrarily chosen as the value shown in table 5. Here, 

SD0-1 values are compared with analyses of the other 

possible standards mentioned above. 

Because many investigators have used the definitions 

of Vine and Tourtelot (1970), it is important to note whether 

this new definition will significantly change their classification of "metal-rich black shales." As table 5 shows, 

SD0-1 is "metal-rich" by the definition of Vine and 

Tourtelot for four trace elements-Be, Co, Mo, and U. 

Relative to "metalliferous" concentrations of 19 trace 

elements (Ti, Mn excluded here) used in the definition of 

Vine and Tourtelot, 8 are higher using the proposed 

definition and 11 are lower. Be, Co, Mo, and U are more 

than two times the "Minimum Enrichment Values" for Vine 

and Tourtelot's definition of metal-rich shales, and Ag, Ba, 

Cr, Sr, V, and Zn are less than half. Changes to lower 

thresholds are at least in part due to improvements in 

analytical techniques (such as for silver). Thus, no adjustments are recommended for the new standard for these five 

elements. The four elements that are high in SD0-1 do 

provide some cause for concern regarding whether metalliferous black shales should be defined on the basis of 

enrichment relative to a black shale that is itself metal rich 

by the older definition. However, defining a black shale as 

metalliferous if it contains the same amount of Be, Co, Mo 

or U as SD0-1 preserves the Vine and Tourtelot definition 

as much as possible. 

If the SD0-1 standard is substituted for the NASC, 

then the proposed definition becomes: 

A metalliferous black shale is a black shale that is 

enriched in any given metal by a factor of 2X (except 

beryllium, cobalt, molybdenum, and uranium, for which IX 

is sufficient) relative to the U.S. Geological Survey Standard SD0-1. 

I recommend the new definition for metalliferous 

black shale, with the noted reservations that SD0-1 is not 

an average black shale and that the definition is somewhat 

arbitrary. The choice exists for continuing to use Vine and 

Tourtelot (with good sample statistics but limited elements 

and analytical precision), using other composite shales 

(each with limited elements and without organic carbon 

analyses), or using SD0-1 (with good analytical statistics 

and a full range of trace elements). Although none of these 

provides an ideal basis for defining a metalliferou" black 

shale, I prefer to use the well-characterized SD9-1. I 

suggest that U.S. Working Group members of IGCP 254 

review their own analyses to determine whether tl'~S new 

definition significantly changes the classification of black 

shales as metalliferous or not. If the designations do not 

shift significantly for the 19 elements used in Vine and 

Tourtelot (1970), then I would have more confidence in 

using the proposed definition for elements heretof0re not 

used. (The question of which elements are significant, as 

noted before, has yet to be fully resolved.) 

CHARACTERIZATION OF BLACK SHAtE 

Given the proposed definition of a black shale., a vast 

variety of shales will be included that require further 

characterization. What is the minimum number of m0difiers 

necessary to characterize a black shale? Table 6 shoPs a list 

of modifiers, not in order of importance but rather in order 

parallel with the Compendium list that Zimmerle and 

Stribmy ( 1989) compiled for "carbon-rich pelitic sediments 

in the Federal Republic of Germany" and whi~h J.S. 

Leventhal (oral commun., 1989) proposed for use in 

developing a similar compendium in the United States. A 

few of these topics have been consolidated in this 

discussion. Location should be as specific as poss ;hie for 

resampling purposes. In addition to stratigraphic position 

and thickness of the entire unit described, scale of variation 

should be noted. If one takes samples randomly from a 

black shale that is several hundred meters thick, the results 

will be meaningless. Consider the Chainman Shale, which 

includes a variety of facies and a phosphatic rr~mber. 

Noting the scale of variation is critical (for example, is it all 

laminated, is there an even or periodic distribution of pyrite, 

does color change?). Determining facies changes within a 

particular bed is similarly important for sampling. This may 

seem obvious, but, in our increasing emphasis on amtlytical 

techniques, we must continue to consider the field methods 

that form the basis for all subsequent work. Regional 

distribution is obvious for paleogeographic, paleoenvironmental, and facies considerations. Similarly, paleontology is needed; complete absence of fauna or va'iations 

in bioturbation are useful indicators of paleoenvironment. 

Petrography includes color (not all black sb=des or 

organic-rich shales are black); fabric (variations h laminations and ichnofabric may have g~netic implications); and 

grain-size distribution; and visual identification of organic 

matter (to clarify organic geochemistry). With today's 

Metalliferous Black ShafP. 47 
Table 4. Summary of USGS SD0-1 characterization study 

No. labs surviving 

Content outlier rejection, used 

in sample in deriving recommended 

as received or average values (N) Recommended 1 Average2 Range3 

PERCENT 

Si02 26 49.28±0.63 

AI2o3 22 12.27±0.23 

Fc20 3T 24 9.34±0.21 

CaO 22 1.05±0.047 

MgO 22 1.54±0.038 

Na

2

o 21 0.38±0.026 

K

2

o 21 3.35±0.061 

P205 19 0.110±0.007 

Ti02 23 0.710±0.031 

MnO 19 0.0419±0.005 

LOI 12 21.7±0.90 

s 7 5.35±0.44 

C02 8 1.01±0.21 

CTm' 12 9.95±0.44 

c (measured) 3 8.98-10 . .1 

org 

c (calculated) 9.678±0.452 or 

No. labs surviving 

Content outlier rejection, used 

in sample in deriving recommended 

Average2 Rangc3 as received or average values (N) Recommended 1 

PARTS PER MILLION 

Ag 2 

As 7 68.5±8.5 

Au 2 

B 5 

Ba 17 397 ±38 

Be 9 3.3±0.57 

Bi 2 

Br 1 

Cd 3 

Ce 18 79.3±7.8 

Cl 1 

Co 23 46.8±6.3 

Cr 24 

Cs 6 

Cu 23 

Dy 5 

Er 3 

Ell 7 

F 2 

Ga 9 16.8±1.8 

Qj 4 

Ge 1 

Hf 6 

increasing concern about the physical characteristics of 

shales, especially permeability, fabric and grain-size 

distribution are especially useful. For example, the 

Nonesuch Shale is a laminated siltstone that has significantly higher horizontal permeability than one might expect 

in a "shale." At the Creta deposit, a copper-rich shale in 

48 Metalliferous Black Shales and Related Ore Deposits 

0.092-0.17 

0.002-0.0035 

128 ±11 

2-<10 

5 

<2-<10 

116 

66.4±7.6 

6.9±1.2 

60.2±9.6 

5.7±0.99 

2.5-4.7 

1.6±0.22 

<0.01-0.07 

6.5±1.2 

1.3 

4.7±0.75 

Oklahoma, sulfide minerals are concentrated along coarser 

grained laminae within the muds hale (Huyck a,d Chorey, 

1989). Thus, thin section petrography can b~ useful in 

studying at least some black shales. 

Mineralogy is useful in interpreting sour~~e and diagenetic evolution of the shale. Stribrny and Urban (1989) 
Table 4. Continued 

No. labs surviving 

Content outlier rejection, used 

in sample in deriving recommended 

as received or average values (N) 

Hg 4 

Ho 2 

In 1 

La 18 

Li 6 

Lu 7 

Mo 15 

Nb 10 

Nd 11 

Ni 25 

Ph 13 

Pr 3 

Rb 11 

Sb 3 

Sc 15 

Se 2 

Sm 7 

Sn 4 

Sr 21 

Ta 5 

Tb 6 

Th 8 

TI 1 

Tm 2 

u 10 

v 20 

w 1 

y 17 

Yb 9 

Zn 23 

'h 17 

Recommended 1 

38.5±4.4 

28.6±5.5 

0.52±0.099 

134 ±21 

11.4±1.2 

36.6±3.3 

99.5±9.9 

27.9±5.2 

13.2±1.5 

7.7±0.81 

75.1±11.0 

10.5±0.55 

48.8±6.5 

160±21 

40.6±6.5 

3.4±0.46 

64.1±6.9 

165 +24 

Average2 

0.19±0.08 

126±3.9 

2.9±0.38 

1.1±0.13 

1.2±0.31 

1.1-3.3 

<0.2 

6-13.8 

4.1-4.8 

3-6.8 

8.3 

0.34-0.56 

3.3 

Analysis of variance with bottle as classification variable could not be calculated if laboratories reported only bottle 

averages or if variance was zero due to failure to report all significant figures. N1 <N always. 

I Recommended N2:5, rsd < 15%, and analysis of variance with method as classification variable showed at least three methods and no 

significant differences between method averages. 

2Average N2:5 but some other condition for (1) not met. 

3Range N<5. 

and Urban and Stribmy (1989) attempted to use chemical 

data to define a normalized mineralogy of shales with their 

"Normative Mineral Compositions" (fig. 2). This technique 

provides a standardized norm for black shales. As Stribmy 

and Urban pointed out, the fine-grained nature of these 

rocks makes quantitative mineralogic determinations 

difficult to impossible. They noted that their technique 

necessarily ignores the presence of certain minerals, such as 

potassium feldspar, by allocating all potassium to illite and 

muscovite. Similarly, magnesium- and iron-chlorites were 

used instead of smectites. One disconcerting omission is the 

possibility that sulfate is present. (Barite is accounted for, 

but the presence of anhydrite could distort pyrite content.) 

Theirs is a useful attempt to provide some mineralogical 

context for study of black shales. Specific knowledge of 

clay mineralogy is useful in understanding shale evolution. 

In particular, smectite/illite transitions are useful where 

observed, and the residence of metals in certain cla:'s needs 

to be better understood (see, for example, Kucha, 1985, in 

the Kupferschiefer). For example, the illites in the 

Flowerpot Shale are 2M polytype; thus, they are detlital, not 

authigenic (Huyck and Chorey, 1989). Presence of 1M 

illites, which form diagenetically, may constrain the burial 

history of shale (for example, the Chainman Shale:; Christensen, 1975). 

Geochemistry includes several factors. In addition to 

standard XRF, ICP or NAA analyses, carbonate carbon 

content, total organic carbon content (TOC), sulfide sulfur 

content (versus total sulfur), and degree of pyritization 

(DOP) are critical for characterizing these shales. Simply 

looking at a low-calcium shale (Quinby-Hunt and others, 

1989) is not sufficient for finding low-carbonate farnples. 

(What about siderite or dolomite?) Additionally, th~ Polish 

Kupferschiefer contains significant carbonate, and yet 

Metalliferous Black Shc-1~ 49 
Table 5. Comparison of SD0-1 with other shale composites 

[N/A indicates not applicable; blank or leaders (--).indicate not ana1y7..ed. Asterisk (*)indicates recommended value (see table 4); do'lblc 

asterisk(**) indicates range midpoint (see table 4); triple asterisk(***) indicates SD0-1 value for Be, Co, U, Mo is less than V+T-B<"'C 

"minimum enrichment value" for "metal-rich shales"; lX is shown to define "metalliferous"] 

V+T MSG SD0-1 V+T-BSC 

SD0-1 BSC BSC "metal- "rretal-

(table 4) (mean)1 NAsc2,3,4 (mean)2 es3 PAAS3•

2 liferous" rich" 1 

MAJOR ELEMENTS OR OXIDES IN WEIGl IT PERCENT 

Si02 49.28 Si 

Al203 12.27 AI 7.0 8.90 8.21 10.00 

Fe203(tot) 9.34 Fe 2.00 4.00 3.68 5.00 

CaO 1.05 Ca 1.5 2.50 1.71 0.93 

MgO 1.54 Mg 0.7 1.70 1.04 1.30 

Na20 0.38 Na 0.7 0.75 0.526 0.89 N/A 

K20 3.35 K 2.00 3.20 2.99 3.10 

P205 0.11 p 

Ti02 0.71 Ti 0.2 0.420 0.434 0.600 0.7 

MnO 0.0419 Mn 0.015 0.046 0.038 0.085 0.0644 0.1 

WI 21.7 

s 5.35 

C02 1.01 

C total 9.95 

C mineral 0.33 

C org(meas) 9.69** 3.2 

C org{calc} 9.678 

RARE-EARTH ELEMENTS IN PARTS PER MilLION 

La 38.5 30 32 44 

Ce 79.3 73 80 

Pr 8.9* 7.9 

Nd 36.6 33 55 

Sm 7.7 5.7 6.2 

Eu 1.6* 1.24 1.27 

Gl 6.5* 5.2 

Tb 1.2* 0.85 0.95 

Dy 6.0* 5.8 4.85 

Ho 1.2* 1.04 

Er 3.6** 3.4 

Tm 0.45** 0.50 

Yb 3.4 3.1 3.10 

I.n 0.54 0.48 0.47 

should not be excluded from black shales. Shales that host 

disseminated gold deposits of the Great Basin may 

intrinsically contain significant amounts of carbonate 

(Bloomstein and Clark, this volume). 

Obviously, organic carbon content is critical, 

especially if it is the basis for defining a black shale. 

However, the weight percent alone does not provide 

sufficient information. At a minimum, type of organic 

content and thermal maturity must be known. Currently, 

some researchers consider the distinction between humic 

and sapropelic carbon to be critical to understanding metal 

associations. B. Kribek (Charles University, Czechoslovakia, written commun., 1990) goes so far as to prefer 

that humic-rich shales be excluded from the definition of 

black shales. Kukal noted but rejected this at the inaugural 

50 Metalliferous Black Shales and Related Ore Deposits 

41.1 38 77.0 70 

81.3 80 158.6 

10.4 8.9 19.8 

40.1 32 73.2 

7.3 5.6 15.4 

1.52 1.1 3.2 

6.03 4.7 13.0 

1.05 0.77 2.4 

4.4 11.4 

1.20 1.0 0.2 

3.55 2.9 7.2 

0.56 0.40 0.90 

3.29 2.8 6.8 

0.58 0.43 1.04 

IGCP 254 meeting (Kukal, 1988). Speczik and Puttman 

(1987) pointed out that the Kupferschiefer locaiJ·• contains 

significant amounts of humic organic material, ye~ this shale 

should not be excluded from the grouping. Sapropelic and 

humic materials, however, may be associated with different 

metals, and this hypothesis should be tested whenever 

possible. Rock-Eval pyrolysis (fig. 3) is a comm'ln method 

that permits at least a first attempt to make this distinction. 

Researchers commonly provide detailed organic descriptions (Poole and Claypool, 1984), correlation~ of total 

organic carbon content and metals (Desborough and others, 

this volume), or crosscorrelations of metals (Frost and 

Chou, 1983) but rarely a combination of these. Combining 

these traits with organic matter petrography W<'luld fill a 

major gap in understanding metalliferous shales. 
Table 5. Continued 

MSG 

SD0-1 BSC 

(table 4) 

V+T 

BSC 

(mcan)1 NAsc2,3,4 (mean)2 PAAS3,2 

SD0-1 

"metalliferous" 

V+T-BSC 

"mctalrich"l 

TRACE ELEMENTS IN PARTS PER MIUJON 

Ag 

As 

Au 

B 

Ba 

Be 

Bi 

Br 

Cd 

Cl 

Co 

Cr 

Cs 

Cu 

Er 

F 

Ga 

Ge 

Hf 

Hg 

In 

Li 

Mo 

Nb 

Ni 

Pb 

Rb 

Sb 

Sc 

Se 

Sn 

Sr 

Ta 

Th 

Tl 

u 

v 

w 

y 

Zn 

'h 

0.131** 

68.5 

0.0028** 

128 

397 

3.3 

5** 

5** 

5** 

116* 

46.8 

66.4* 

6.9* 

60.2* 

3.6** 

0.035** 

16.8 

1.3** 

4.7* 

2.2** 

0.1 ** 

28.6 

134 

11.4 

99.5 

27.9 

126* 

4.45** 

13.2 

4.9** 

29* 

75.1 

1.1 * 

10.5 

8.3** 

48.8 

160 

3.3** 

40.6 

64.1 

165 

<1 

50 

300 

1 

10 

100 

70 

20 

10 

50 

20 

10 

200 

2 

150 

30 

<300 

70 

lvine and Tourtelot (1970). 

2Quinby-Hunt and others (1989). 

3Taylor and McLennan (1988). 

28.4 

636 

0.69 

25.7 

124.5 

5.16 

6.30 

58 

125 

2.09 

14.9 

142 

1.12 

12.3 

2.66 

2.1 

200 

4Gromet and others (1984) (neutron activation analysis). 

Thermal maturity of organic sedimentary rocks is 

similarly important. For example, Kribek (1989) noticed 

that as a sapropelic black shale is metamorphosed, 

decreasing As, Mo, Pb, U, V, Zn, Sb, Ag, and Au contents 

indicate mobilization of these metals. In fact, Kribek 

considered the metal concentrations to vary more strongly 

with chemical maturity and metamorphic grade than with 

total organic carbon content. Poole and Claypool ( 1984) 

focused on the petroleum potential in black shales in the 

Great Basin and noted that organic matter had moved out of 

28.8 

0.023 

1,720 

4.0 

240 

16.9 

111 

8.6 

21.9 

4.3 

0.21 

65 

131 

5.7 

15.6 

5.6 

310 

0.9 

11.6 

15.2 

500 

3.3 

310 

230 

650 

23 

110 

15 

85 

5.0 

1.0 

160 

16 

200 

14.6 

3.1 

150 

2.7 

85 

210 

0.262 

137 

0.0056 

256 

694 

3.3*** 

10 

10 

10 

232 

46.8*** 

132.8 

13.8 

120.4 

7.2 

0.07 

33.6 

2.6 

9.4 

4.4 

0.2 

56.2 

134*** 

22.8 

199.0 

55.8 

252 

8.9 

26.4 

9.8 

58 

150.2 

2.2 

21.0 

16.6 

48.8*** 

320 

6.6 

81.2 

128.2 

330 

7 

2(f) 

1,0(0 

3 

~0 

7f') 

2C'l 

:o 

200 

300 

100 

?0 

1,500 

30 

1,000 

70 

1,500 

200 

these shales in certain parts of the basin. This mobU.: ~y is the 

reason why shale that was once "black" may now contain 

less than 0.3 percent total organic carbon. Thus, thennal 

maturity affects both organic carbon and metal contents in 

shale. Initial attempts to detennine thennal maturity may 

use the correlation of different methods, as presented by 

Poole and Claypool (1984) and shown on figure 4. 

Additional measures of thermal maturity of shale include 

crystallinity of authigenic illite and degree of graphitization. 

Illite crystallinity provides relative comparison of thermal 

Metalliferous Black Shale 51 
Table 6. U.S. Working Group IGCP Project 254, Metalliferous Black Shales 

[Modified after Zimmerle and Stribrny, 1989] 

NAME 

LOCATION 

STRATIGRAPIDC POSffiON 

Scale of variation 

REGIONAL DISTRIBUTION 

THICKNESS 

PETROGRAPHY 

Grain size/texture 

Fabric 

Organic material identification (inertinite/vitrinite, etc.) 

MINERALOGY 

GEOCHEMISTRY 

Organic carbon and carbonate carbon 

Sulfide sulfur 

Degree of pyritization (DOP) 

Major, minor, and trace elements 

Organic geochemistry 

Organic type (e.g. sapropclic/humic; biomarkers) 

Thermal maturity (diagenesis/catagenesis/metamorphism) 

PALEONTOLOGY 

Bioturbation 

Identification and compactional features 

DEPOSillONAL ENVIRONMENT, FACIES 

COLOR 

FURTHER REMARKS 

REFERENCES 

AUTHOR(S) 

maturity, although it has not been correlated with the 

indicators shown in figure 4. (Definitions for types of 

organic material are also vague; for example, the term 

bitumen is used in a variety of contexts.) Degree of 

graphitization is helpful for comparing metamorphosed 

shales. (Discussion of characterization or genesis of 

graphitic schists is not within the scope of this paper, 

although it is an issue that needs to be addressed.) 

52 Metalliferous Black Shales and Related Ore Deposits 

Finally, a critical analysis is DOP, or degree of 

pyritization, defined as sulfide iron divided by t'le sum of 

sulfide iron and acid-soluble iron. Plots of organic carbon 

versus DOP are a refinement of carbon versus sdfur plots, 

which are themselves useful for distinguishing among lake 

sediments, normal marine sediments, and euxiric marine 

sediments (Berner and Raiswell, 1983; Leventhal, 1983) 

(fig. 5). As Berner, Raiswell, and associates hrve shown 
1000 

I Algal- ,/ sapropelic I 

X 

w 

0 

z 

800 I 

I 

I 

I 

I 

I 

600 I ,-- II 

z ! // Sapropelic 

~ I I 

I I 0 I I 

> ~ 400 ~'·- • .,,. • 

:t: I ••• • 

. i·~·· . 200 • , ••• I e 

••• • • 1 • • 

•• ' m I ,,..------ / Humic 

• • 

0~----~~--- -------~------~ 

0 50 100 150 200 

OXYGEN INDEX 

Figure 3. Plot of hydrogen index versus oxygen index for 

different kerogen types in Chainman Shale cuttings (Poole 

and Claypool, 1984, fig. 14), as an example of information 

provided by Rock-Eval analysis. Note different types of 

kerogen source. Main types of kerogen show evolution 

paths toward the origin as maturity increases. Hydrogen 

index is milligrams of hydrocarbons per gram of organic 

carbon; oxygen index is milligrams C02 per gram organic 

carbon. 

(figs. 6, 7), measurement of DOP also differentiates the 

timing of pyrite formation (syngenetic versus diagenetic) 

and the limiting factor on pyrite formation (iron versus 

carbon). Because certain trace metals are strongly associated with sulfide minerals, understanding the timing and 

conditions of sulfide formation is critical. 

A brief description of the proposed standard SD0-1 

is available and includes some of the characteristics noted 

above. SD0-1, Ohio Shale (Devonian), is a "brownishblack (5YR2/l) shale" (Kepferle and others, 1985) sampled 

from a 3.05-m-thick zone in the lower part of the Huron 

Member of the Ohio Shale. The sample locality is a roadcut 

on Interstate 64, approximately 13.7 km (8.5 mi) west of 

Morehead in western Rowan County, Kentucky ("Locality 

A" in Kepferle, 1986). Provo and others (1977) described 

the shale as fissile, brittle, pyritic, and containing fossils 

such as Tasmanites, conodonts, and woody plant fragments. 

Thin section analysis (Kepferle and others, 1985, table 7) 

indicates an organic-rich mudshale (using the shale classification in table 2) in which quartz-rich, silty laminae 

Table 7. Modal contents of SD0-1 

[In percent. From Kepferle and others (1985)] 

Macerals ......................................... 4 9 

Clay ( <0.002 nun) ............................. 17 

Quartz ............................................. 15 

Pyrite ............................................. 12 

Organic sporomorphs ........................... 2. 5 

Gypsum ............................................ 2 

Mica ................................................ 1.5 

Feldspar ............................................ 0. 5 

Dolomite ........................................... 0.5 

contain scattered conodonts. R. Schultz (University of 

Cincinnati, oral commun., 1990) has obtained a DOP of 

0.71, and J.S. Leventhal and C. Taylor (U.S. Geological 

Survey, oral commun., 1990) have obtained DOP' s l'"~tween 

0.74 and 0.78 (three determinations). 

I consider the above characteristics to be essential for 

proper comparison among black shales and metalliferous 

black shales. Once these parameters have been dete-mined, 

more sophisticated analyses, including stable isotopic 

studies, organic geochemistry, organic oxidation/polymerization (Speczik and Puttman, 1987, 1989), trace metal 

crosscorrelation, residences of metals in minerals and 

organics, metal associations (sapropelic versus hmric) and 

mobilities, and modelling of metal behavior in blacJ ~ shales 

can be attempted. Otherwise, we risk comparing the 

sedimentary versions of apples, oranges, and rutabagas. 

Recent studies have moved in this direction as tec"-niques 

become more accessible; however, we are by no means 

finished. Raising these issues as part of the questior of just 

how to define a metalliferous black shale, and in the hope of 

filling the gaps in some of the mineralogical and geochemical studies already accomplished, will be another step 

toward understanding how black shales and, parti ~ularly, 

metalliferous black shales form. 

Acknowledgments.-Many of the references used in 

this paper and comments or suggestions have come from 

participants in the IGCP Project 254. Thanks go to the 

following, in alphabetical order: Robert W. Chon~y, Fan 

Delian, George Desborough, C.S. Ferris, Eric Force, 

Richard Grauch, Roy Kepferle, Bohdan Kribek, Zdenek 

Kukal, Joel Leventhal, Michael Lewan, Timothy Lyons, 

Edwin K. Maughan, J. Barry Maynard, Jan Pasava, Paul E. 

Potter, Forrest G. Poole, Richard B. Schultz, and John 

Trammell for their written comments. The views expressed, 

however, are solely mine. 

REFERENCES CITED 

American Society for Testing and Materials, 1978, Standard 

specifications for classification of coals by rank (ASTM 

designation 0388-77): 1978 Annual Book of ASTI~ Standards, pt. 26, p. 220-224. 

Metalliferous Black Sha•~ 53 
STAGES QUALITATIVE H/C PYROL- TEMP- VITRINITE 

STAGES YSIS ERATUAE C"lNODONT 

COLOR 

ALTERATION 

INDEX 

OF INTER- ATOMIC TRANS- coc) OF REFLEC- COAL 

PRETATION OF OIL RATIO FORM- MAX TANCE CLASSORGANIC OF ORGANIC GENERATION OF ATION PYROi..- (Rm ~) IFICATION 

MATTER MATTER AND SAPRO- RATIO YSIS OF 

TRANS- THERMAL PRESERVATION PELIC (___!.!_ ~ YIELD 1 HUMIC (ASTM, 1978) 

FORMATION MATURITY KEROGEN s 1

+s2) (S2PEAKJKEROGEN (CAl) 2 

DIAGENESIS 

CATAGENESIS 

SUBMATURE 

MATURE 

SUPERMETA- MATURE w 

GENESIS ~ ..J 

CONDENSATE/WET 

GAS 

PRESERVATION 

LIMIT 

LIGNITE 

A 

-PALE 1

·

5 BROWN 

BROWN 

TO 

2 DARK 

BROWN 

MEDIUM 

VOLATILE GRAYISH 

t-----t BROWN 

LOWVOLATLE 

3 DTA~K REDDISH 

BROWN 

~--SEMIANTHRACITE 4 

BLACK 

ANTHRACITE 

5 

1 S1 /S1+S2ratio and S2 peak (Tmax°C) applicable only to mature and submature kerogen. 

2 Epstein and others ( 1977). 

Figure 4. Various geochemical indicators of thermal maturity of organic material and stages of hydrocarbon gen~ration and 

preservation. Modified from Poole and Claypool (1984, fig. 9). 

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metamorphism on organic matter in mudrock: American 

Association of Petroleum Geologists Bulletin, v. 54, 

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Bates, R.L., and Jackson, J.A., 1987, Glossary of geology (3rd 

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pyrite sulfur in sediments over Phanerozoic time-A new 

theory: Geochimica et Cosmochimica Acta, v. 47. 

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54 Metalliferous Black Shales and Related Ore Deposits 

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Degens, E.T., Meyers, P.A., and Brassell, S.C., eds., 1986, 

Biogeochemistry of black shales: Mittleilung~n aus dem 

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Frost, J.K., and Chou, C.L., 1983, Trace element geochemistry of 

the New Albany Shale Group (Devonian-Mis~issipian) in 

Illinois-Implications for depositional envirorment: 1983 

Eastern Oil Shale Symposium, University <Jf Kentucky 
2.5 

a: 

:::> 2.0 

u. 

...J 

:::> 

en 1.5 

~ 

z 1.0 w 

() 

a: 

w 0.5 

a.. . • 

,.. ... 0 

0 2.0 4.0 6.0 8.0 

PERCENT ORGANIC CARBON 

Figure 5. Organic carbon versus reduced sulfur for modern freshwater lake sediments (Leventhal, 

1983) and normal marine sediments (Berner and Raiswell, 1983, fig. 2). 

Institute for Mining and Minerals Research and the 

Kentucky Energy Cabinet, p. 181-194. 

Green, J., 1959, Geochemical table of the elements for 1959: 

Geologic Society of America Bulletin, v. 70, no. 9, 

p. 1127-1183. 

Gromet, P.L., Dymek, R.F., Haskin, L.A., and Korotev, R.L., 

1984, The "North American shale composite"-Its 

compilation, major and trace element characteristics: 

Geochimica et Cosmochimica Acta, v. 48, p. 2469-2482. 

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of Creta and Kupferschiefer copper shales-Applications to 

mineralizing models: International Geological Congress, 

28th, Washington, D.C., Abstracts, v. 2, p. 90. 

Kane, J., Arbogast, B., and Leventhal, J., 1990, Characterization of 

Devonian Ohio Shale SD0-1 as a USGS Geochemical 

Reference Standard: Geostandards Newsletter, v. 14, no. 1, 

p. 169-196. 

Kepferle, R.C., 1986, Devonian and Mississippian black shales of 

Kentucky: Geological Society of America Centennial Field 

Guide-Southeastern Section, p. 31-36. 

Kepferle, R.C., de Witt, W., Jr., and Flanagan, F.J., 1985, Ohio 

Shale (Devonian), SDO-l from Rowan County, Kentucky: 

U.S. Geological Survey Open-File Report 85-145, 14 p. 

Krauskopf, K.B., 1979, Introduction to geochemistry (2nd ed.): 

New York, McGraw-Hill, p. 544-546. 

Kribek, B., 1989, Lithological and metamorphic development of 

anoxic environment in geological history of the Bohemian 

Massif: International Geological Congress, 28th, Washington, D.C., Abstracts, v. 2, p. 228. 

Kucha, H., 1985, Feldspar, clay, organic and carbonate receptors 

of heavy metals in Zechsteicn deposits (Kupferschiefertype), Poland: Institution of Mining and Metallurgy 

Transactions, sec. B, v. 94, p. B133-B146. 

Kukal, Z., 1988, Deposition of black shales-Why, where and 

when? (with special attention to the Bohemian Massif), in 

Pasava, J., and Gabriel, Z., eds., Proceedings of the 

Inaugural Meeting of the IGCP 254: Geological Survey of 

Czechoslovakia, Prague, p. 51-55. 

Leventhal, J.S., 1983, An interpretation of carbon ani sulfur 

relationships in Black Sea sediments as indicators of 

envimoments of deposition: Geochimica et Cosmcchimica 

Acta, v. 47, p. 133-137. 

Lewan, M.D., 1987, Petrographic study of primary p~troleum 

migration in the Woodford Shale and related rock units, in 

Doligez, B., ed., Migration of hydrocarbons in sedimentary 

basins: lnstitut Francais du Petrole Collection Coli 'lques et 

Seminaires 45, p. 113-130. 

Poole, F.G., and Claypool, G.E., 1984, Petroleum sou .. ce-rock 

potential and crude-oil correlation in the Great F~J.sin, in 

Woodward, J., Meissner, F.F. and Clayton, J.L., eds., 

Hydrocarbon source rocks of the Greater Rocky Mountain 

Region: Rocky Mountain Association of Ge-:llogists, 

Denver, Colorado, p. 179-229. 

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of shale: New York, Springer-Verlag, 306 p. 

Provo, L.J ., Kepferle, R.C., and Potter, P.E., 1977, Three Lick 

Bed-Useful stratigraphic marker in Upper Devoniln Shale 

in eastern Kentucky and adjacent areas of Ohb, West 

Virginia, and Tennessee: U.S. Energy Research and 

Development Administration, Morgantown Energy 

Research Center Report MERC/CR-77-2, 56 p. 

Quinby-Hunt, M.S., Wilde, P., Orth, C.J., and Berry, W.B.N., 

1989, Elemental geochemistry of black shales-S'=ttistical 

comparison of low-calcic shales and other shal~~s: U.S. 

Geological Survey Circular 1 037, p. 8-15. 

Raiswell, R., and Berner, R.A., 1985, Pyrite formation in euxinic 

and semi-euxinic sediments: American Journal of Science, 

v. 285, p. 710-724. 

Metalliferous Black Sha~~ 55 
~ t z 

Wa: 

0::;:) 

a:LL 

w..J 

0..::;:) 

U) 

t 

0.. 

0 

c 

PERCENT ORGANIC 

CARBON • 

PERCENT ORGANIC 

CARBON • 

Figure 6. Idealized plots of organic carbon versus pyrite 

sulfur (percent sulfur) and degree of pyritization (DOP) for a 

hypothetical euxinic sediment. The plots show formation of 

iron-limited syngenetic pyrite alone, as indicated by a 

uniform DOP as organic carbon content increases. The 

heavy dashed line is that expected for a normal marine 

sediment, as in figure 5. Modified from Raiswell and Berner 

(1985, fig. 2). 

___ 1987, Organic carbon losses during burial and thermal 

maturation of normal marine shales: Geology, v. 15, 

p. 853-856. 

Spears, D.A., 1980, Towards a classification of shales: Journal of 

the Geological Society, v. 137, p. 123-130. 

Speczik, S., and Puttman, W., 1987, Origin of Kupferschiefer 

mineralization as suggested by coal petrology and organic 

geochemical studies: Acta Geologica Polonica, v. 37, no. 

3-4, p. 167-187. 

___ 1989, Oxidation of organic matter and its influence on 

Kupferschiefer mineralization of southwestern Poland: 

International Geological Congress, 28th, Washington, D.C., 

Abstracts, v. 3, p. 160. 

Stribrny, B., and Urban, H., 1989, Classification of sedimentary 

rocks in the black shale series based on their normative 

mineral compositions: International Geological Congress, 

28th, Washington, D.C., Abstracts, v. 3, p. 190-191. 

Taylor, S.R., and McLennan, S.M., 1988, The significance of the 

rare earths in geochemistry and cosmochemistry, in 

Gschneidner, K.A., Jr., and Eyring, L., eds., Handbook on 

56 Metalliferous Black Shales and Related Ore Deposits 

~t Wa: 

0::;:) 

fl:LL 

W..J 

0..::;:) 

U) 

t 

0.. 

0 

c 

f Diagenetic 

+ pyrite _,. 

tSyngenetic- -,... .,. ,... "(\8 1 pyrite ,- ~e.t' • ~~a\,,. 

I ,_ .. \Q{\P .,-+' ,, 

PERCENT ORGANIC 

CARBON • 

PERCENT ORGANIC 

CARBON • 

Figure 7. Idealized plots of organic carbon versus pyrite 

sulfur (percent sulfur) and degree of pyritization (DOP) for a 

hypothetical euxinic environment, as in figure 6. These 

plots show formation of extra carbon-limited diagenetic 

pyrite, as indicated by the increase in DOP 2s organic 

carbon content increases. Modified from Raiswell and 

Berner (1985, fig. 1 ). 

the physics and chemistry of rare earths, v. 11: New York, 

Elsevier, p. 485-578. 

Tourtelot, H.A., 1960, Origin and use of the word "shale": 

American Journal of Science, v. 258-A, p. 33~·-343. 

Urban, H., and Stribrny, B., 1989, On the classificaf,')n of black 

shales: Terra Abstracts, v. 1, p. 13. 

Vine, J.D., and Tourtelot, E.B., 1970, Geochemistry of black 

shales-A summary report: Economic Geohgy, v. 65, 

p. 253-272. 

Waples, D.W., 1983, Reappraisal of anoxia and organic richness, 

with emphasis on Cretaceous of North Atlanti~~: American 

Association of Petroleum Geologists Bulletin, v. 67, 

p. 963-978. 

Zimmerle, W., and Stribrny, B., eds., 1989, Organic carbon-rich 

pelitic sediments in the Federal Republic of Germany, 

Diskussionsvorlage fur die 2. Arbeitstagung am 1.-2., Juni 

1989 in Korbach: Institut fur Geochemie, Petrologie und 

Lagerstattenkunde, J.W. Goethe-Universitat Frankfurt, 

25 p. 
Recent Black Sea Sediments-Leg 4, 

1988 Black Sea Expedition 

By Timothy W. Lyons 

The Black Sea is the type euxinic basin and, as 

such, a frequently cited analog for the depositional environment of ancient black shales. Its strongly stratified 

water column is permanently anoxic and sulfidic below 

approximately 100 m (the 0 2/H2S interface is somewhat 

deeper in the marginal regions of the basin). The 1988 

RN Knorr Black Sea Oceanographic Expedition provided 

a unique opportunity to investigate many aspects of this 

basin in great detail and, thus, to test the validity of the 

"Black Sea model." The principal objectives of this study 

are twofold: ( 1) an improved understanding of euxinicbasin sediments and pyrite formation (carbon-sulfur-iron 

systematics) and (2) comparison of the sediments of oxic 

and anoxic depositional settings in terms of chemistry and 

general sedimentology. 

Box-core sediments collected during Leg 4 of the 

1988 expedition reveal a variety of uppermost Holocene 

sedimentary facies sampled over a broad region of the 

southern Black Sea basin; cores are included from two 

transects across the intersection of the water-column oxicanoxic interface with the basin-margin substrate (Bay of 

Sinop region and immediately west of the Bosporus) 

(fig. 1, table 1). The sediments sampled during Leg 4 include: (1) muddy, gray turbidite layers in the deep basin 

from a few to several tens of centimeters thick and characterized by a predominance of fine grain sizes (fine-silt 

to clay) and remarkable textural and chemical homogeneity (stations 7, 8, 11, 18A, and 19), (2) an array of 

closely spaced sediment types across the oxyclinesubstrate intersection varying from a highly bioturbated, 

shell-rich oxic facies to dark-gray to black, water-rich, 

laminated muds from the anoxic zone, and (3) coccolithrich, microlaminated sediments of the abyssal Black Sea 

consisting of couplets of alternating white (coccolith dominated) and dark-brown to black (siliciclastic dominated) 

millimeter-scale laminae (stations 9, 14, and 18A). These 

1

Department of Geology and Geophysics, Yale University, New 

Haven, Connecticut 06511. 

micro laminated muds comprise the "Unit 1" sediment of 

the widely used Black Sea nomenclature scheme c f Ross 

and others (1970) and Ross and Degens (1974). The 

light-dark pairs may derive from variability in sedimentation occurring on a seasonal scale and, as a conseauence, 

may represent annual varve couplets. However, there currently exists an unresolved disparity between varv~-count 

and radiometric age determinations for Unit 1. 

The turbiditic mud layers display strongly conformable basal contacts that suggest negligible erosion associated with emplacement. The layers are in both stacked 

multiturbidite packages, including as many as eight separate "events" in approximately 50 em of core, ~nd sequences of interbedded turbidite mud and undisturbed 

Unit 1 "varved" material. These muds range fron massive to moderately well laminated. Multiple corir'! at a 

single station reveals dramatic local-scale variation in turbidite spatial relationships. The exact mechanisn connected with the deposition of these muddy gray layers 

remains unknown. Sandy turbidites were encountered in 

the vicinities of stations 18A and 19. 

Superimposed on the relatively fine scale lamination 

of the basin-margin anoxic-zone sediments at sta•ions 5 

and 15, as detected by X-radiography, is a large~ scale 

(several centimeters), enigmatic, black and da:"'k-gray 

banding. The black pigments are a consequence of strong 

enrichments in acid-volatile iron monosulfides ("FeS"). 

These anomalous enrichments reflect, at least in p'frt, the 

high rates of sedimentation at these sites. Similarly, cores 

of gray-brown sediment from stations 16B and 26 of the 

Bay of Sinop transect contain black "FeS" bands. The 

sediments of 16B and 26 were deposited very proximal to 

the position of the oxic-anoxic interface at the time of 

coring at sites where bottom-water dissolved-oxyg~n concentrations were found to be at trace to null leve1

1i. The 

sediments of 16B, as viewed in X-radiography, di:~ulay a 

combination of discrete burrows, a shelly taxa, anc a disturbed lamination-a very transitional characte.. with 

respect to the oxic and anoxic end members of the 

transect. 

Recent Black Sea Sediments 57 
Table 1. Water depths at Leg 4 boxcoring stations 

Water depth 

Station (meters) 

3 85 

4 115 

5 233 

7 1,949 

8 2,128 

9 2,094 

11 2,175 

14 2,218 

15 198 

16 129 

16B 160 

17 97 

18A 2,150 

19 1,620 

26 170 

A particularly well developed (and preserved) 

benthic-boundary flocculent layer ("fluff la:·er") was 

observed in the deeper water box cores. This fluff layer 

was found overlying both gray turbidite and Urit 1 muds. 

Varve packets, as well as individual laminae, V'ere correlated among several stations (9, 14, and 18A) over a distance of approximately 500 km. 

REFERENCES CITED 

Ross, D.A., and Degens, E.T., 1974, Recent sedimerrs of Black 

Sea, in Degens, E.T. and Ross, D.A., eds., The Black 

Sea-Geology, chemistry, and biology: Ame-ican Association of Petroleum Geologists Memoir 20, p. 183-199. 

Ross, D.A., Degens, E.T., and Macllvaine, J., 1970, Black 

Sea-Recent sedimentary history: Science, v. 170, 

p. 163-165. 

Figure 1. Box-coring stations of Leg 4 of the 1988 Black Sea Expedition (insert shows detailed map of the Bay of Sinop region). 

58 Metalliferous Black Shales and Related Ore Deposits 
Organic Geochemical Studies of 

Metal I iferous Parts of the 

Middle Proterozoic Nonesuch 

Formation of Northern Michigan 

By Philip A. Meyers1 

1 Eileen S. Ho1 1 and Jeffrey L. Mauk1 

Abstract 

Organic matter in metalliferous parts of the Nonesuch 

Formation of northern Michigan was characterized by 

isotopic, molecular, and spectrophotometric procedures and 

compared to organic matter in nonmetalliferous sections. 

Samples from the White Pine copper mine contain little 

organic carbon in comparison to samples from outside the 

mine area. Residual organic matter in mine samples is low in 

solvent-extractable matter and relatively aromatic in character, 

yet no difference in carbon isotopic contents is evident 

between kerogen isolated from metalliferous and nonmetalliferous rocks. 

INTRODUCTION 

The common association of metallic ore deposits and 

rocks enriched in organic carbon implies that organic matter 

was involved in formation of the mineralized rocks. A 

postulated role of the organic matter is as a reductant of 

metal-bearing solutions that have migrated through these 

rocks. Selective losses and alterations of the organic matter 

would accompany precipitation of minerals. Piittmann and 

others (1988) documented, for example, the loss of 

extractable aliphatic hydrocarbons and the sulfidization of 

aromatic hydrocarbons that evidently resulted from deposition of copper and silver ores in the Permian Kupferschiefer 

of Poland. 

THE NONESUCH FORMATION 

The Nonesuch Formation of northern Michigan was 

deposited under a freshwater lake created by rifting of the 

1

Department of Geological Sciences, University of Michigan. Ann 

Arbor, Michigan 48109-1063. 

North American craton during Keweenawan time (ca. 1.1 

Ga) of the Middle Proterozoic Era. The formation CC'~tains 

sandstones, siltstones, shales, and carbonate laminit~~s and 

has organic carbon contents as high as 3 weight percent. The 

lower part of the Nonesuch is organized into informal units 

called, in ascending order, the parting shale, the upper 

sandstone, and the upper shale (fig. 1). As summarized by 

Barghoorn and others (1965) and lmbus and others (1988), 

the section represents an evolution of the depositional 

setting from marginal lacustrine to deep lacustrine to fluvial 

lacustrine. Euxinic shales and siltstones form the mqiority 

of the rock types, and their average thickness is 18C m. 

Copper-rich solutions are believed to have migrated 

into the Nonesuch Formation where interaction with 

organic-carbon-rich rock layers precipitated copp~r-iron 

sulfide minerals and native copper and silver (Wiese, 1973; 

Kelly and Nishioka, 1985). Because copper-mine¥alized 

rocks are generally restricted to the base of the Nonesuch 

Formation and to the top of the underlying Copper Harbor 

Conglomerate, the migrating fluids are believed to have 

entered the Nonesuch Formation from below (White, 1971 ). 

Although the Nonesuch Formation is regionally extensive, 

copper-mineralized rocks reach ore grades only locqlly in 

the vicinity of the White Pine Mine (Ensign and others, 

1968). 

SAMPLES AND PROCEDURES 

We obtained metalliferous rock samples from within 

the White Pine Mine from below, at, and above the contact 

between the Nonesuch Formation and the underlying 

Copper Harbor Conglomerate. The rock units sampled 

include the lower sandstone of the Copper Harbor rnd the 

domino shale of the parting shale and the thinly shak of the 

upper shale of the Nonesuch Formation (fig. 1 ). Active 

petroleum seeps are present locally in the mine (Eglinton 

Organic Geochemical Studies of Metalliferous Parts of the Middle Proterozoic Nonesuch Formation 59 
16.5 

15 

~··· Cll 

~ f-o 

~ 

::II ~ 

= < 

~ ::r: 

rJ) 

(.) 

Cll ~ 

5 r:.:l 

p... 

p... 

::::> 

4 

z 

3 

0 

~I ~ 

~ 

--< rJ) 

~ ~ 

~ r:.:l 

0 p... 

p... 

~ ::::> 2 

~ 

~ ~ u < ~ ::r: 

V'J r.J) ~ ~ ~I z f:-4 

0 ~ 

< z p... 

COPPER 

HARBOR FM. 

MARKER BED: Black thinly laminated siltstone "'rith abundant white 

calcareous blebs. Thickness 

about 3 meters. 

Massive black siltstone. 

STRIPEY: Finely laminated black 

silty shale "'rith abundant calcite cement. 

Massive gray siltstone in graded 

beds 10 to 50 em thick. 

Contains coarse-grained sandstone beds towards the south 

RED AND GRAY: Widely laminated 

greenish gray siltstone and red 

shale. 

WIDELY: Widely laminated greenish 

gray siltstone and gray shale. 

UZV (UPPER ZONE OF VALUES): 

Massive dark gra siltstone. 

BROWN MASSIVE: Reddish bro11'D to gray massive siltstone with 

calcite nodules near base. 

THINLY: Thinly laminated dark gra 

siltstone and black shale. 

UPPER TRANsmoN: Fine-grained 

sandstone with black shale 

artings. 

UPPER SANDSTONE: Red to gray 

fine- to coarse-grained 

sandstone. Locally contains 

conglomeratic lenses. Reddish 

shale and siltstone common in 

middle part of unit. 

PERCENT 

COPPER 

5 

Figure 1. Stratigraphy of the upper part of the Copper Harbor Conglomerate and 

the Nonesuch Formation in the area of the White Pine Mine, northern Michigan. 

and others, 1964; Barghoom and others, 1965); our samples 

were selected to avoid these seeps. 

Organic carbon contents were determined by removing carbonate minerals from dried and ground samples 

using 3N HCl and measuring the amount of residual carbon 

using a Hewlett-Packard 185B CHN analyzer. Lack of 

measurable amounts of nitrogen precluded determination of 

organic matter carbon/nitrogen values. Organic carbon 

stable isotope ratios were obtained from carbonate-free 

samples using a VG Micromass 602 mass spectrometer and 

are reported relative to the PDB standard. Rock-Eval 

analyses were done using a Delsi Nermag Rock-Eval II 

instrument. 

60 Metalliferous Black Shales and Related Ore Deposits 

Extractable matter was obtained from dried and 

ground samples by Soxhlet extraction using f mixture of 

toluene and methanol, 3/1, and refluxing fo"' 48 hours. 

Because so little matter was extracted from th~ samples, it 

was not fractionated prior to analysis. The total extracted 

material was analyzed using a Hewlett-Packard 5830 FID 

gas chromatograph equipped with a 20-m SE-54 capillary 

column and a splitless injection system. 

To isolate kerogen from the samples, rod-:s were first 

ground and then extracted with organic solvents to remove 

lipid materials. Carbonate minerals were removed by 

dissolution with concentrated HCl, followed by rinsing with 

distilled water. Concentrated HF was then adcled at room 
Table 1. Carbon isotope ratios, organic carbon concentrations, and concentrations of total extractable material in 

samples of the Nonesuch Formation from the White Pine Mine 

[nd indicates not detcnnined] 

Sample 

WP-5 

WP-6 

WP-7 

WP-9 

WP-10 

WPM88-024 

WPM88-025 

WP-3 

WP-4 

WP-11 

WP-8 

WPM88-190 

WPM88-192 

a13c 

Stratum (%o PDB) 

Thinly shale ............................. nd 

Thinly shale ........................... -31.32 

Thinly shale ........................... -31.82 

Thinly shale ........................... -33.45 

Thinly shale ........................... -33.58 

Thinly shale ........................... -33.50 

Thinly shale ........................... -33.53 

Domino shale ........................... nd 

Domino shale ........................... nd 

Domino shale......................... nd 

Lower sandstone ...................... -23.95 

Lower sandstone ...................... -33.35 

Lower sandstone ...................... -33.41 

temperature to remove silicate minerals. This step was 

repeated several times until no more mineral material 

remained. If fluoride minerals formed during the HF 

treatment, additional HCl was added to dissolve them so 

that distilled water rinses might remove the neoformed 

fluorides from the kerogen plus chalcocite residue. During 

kerogen isolation from samples of the lower sandstone, 

floating dark-colored matter was obtained after the rock had 

been dissolved. This was collected and analyzed separately 

from the bulk kerogen. 

After the insoluble residue from the rock dissolution 

was oven-dried, it was analyzed using Fourier transform 

infrared (FTIR) spectroscopy. This analysis was achieved 

by forming pressed pellets from finely ground mixtures of 

KBr and the kerogen isolates and scanning the pellets from 

4,000 cm-1 to 400 cm-1

, using a Nicolet 5-DX spectrometer 

in transmittance mode. 

RESULTS AND DISCUSSION 

Rock samples from metalliferous rocks in the White 

Pine Mine contain little organic matter (table 1), whereas 

nonmetalliferous parts of the Nonesuch Formation contain 

as much as 2 percent organic carbon (Imbus and others, 

1988). The samples from the domino stratum of the parting 

shale, near the base of the metalliferous zone, have an 

average organic carbon content of 0.17 percent, and the 

samples from the thinly stratum of the upper shale have an 

average content of 0.26 percent. Concentrations of total 

solvent-extractable material in the lower sandstone samples 

(11 ppm) and in the thinly shale samples (average 30 ppm) 

are low for petroleum source rocks (Tissot and Welte, 1984, 

p. 177). In contrast, extractions from nonmetalliferous core 

and surface outcrop samples indicate that parts of the 

Nonesuch Formation which overlie the ore-bearing strata 

% corg 

(weight percent) 

0.21 

0.47 

0.16 

0.25 

0.19 

nd 

nd 

0.08 

0.35 

0.07 

0.35 

nd 

nd 

Total extract 

(ppm) 

nd 

49.6 

26.7 

24.5 

18.7 

nd 

nd 

nd 

nd 

nd 

11.3 

nd 

nd 

are rich in hydrocarbons (lmbus and others, 1988; Hieshima 

and others, 1989). 

Organic carbon in kerogen isolated from beth the 

thinly shale and the lower sandstone is isotopically light, 

having o13C values between -31 %o and -34%o (PDB). These 

values are similar to those reported by Barghoom and others 

(1965) for kerogen from a metalliferous sample rnd by 

lmbus and others ( 1988) for nonmetalliferous sampl~s. The 

mineralization process and postulated oxidation of C' .. ganic 

carbon evidently did not cause an isotopic shift. One sample 

of the lower sandstone, WP-8, gave a markedly l'~avier 

isotope ratio of -23.95%o. This sample may have contained 

some residual carbonate carbon, inasmuch as its measured 

"organic" carbon value of 0.35 percent is high for a 

sandstone having little extractable matter, and Barghoom 

and others (1965) showed that carbonate carbon in the 

Nonesuch Formation has o13C values of about -4%o (PDB). 

Comparison of chromatograms of the total extractable 

material from metalliferous rocks and of the extractable 

aliphatic hydrocarbon fraction from samples of noncupriferous rocks collected away from the mine area reveals 

important differences (fig. 2). Although some of the peaks 

in the total extract trace may not be hydrocarbons, these 

differences are significant. Whereas the noncupriferous 

extract distribution is dominated by a range of n-alkar,~s. the 

pattern for the metalliferous sample shows few o:r these 

hydrocarbons. Instead, the distribution resembles those 

shown for hydrothermally altered basal rocks frC''ll the 

Kupferschiefer (Pttmann and others, 1988), in y•hich 

oxidation of aliphatic organic matter by mineral-l'~aring 

fluids is postulated. 

Rock-Eval pyrolyses of metalliferous rock s1mples 

are generally not informative because the rocks conta:, little 

organic matter. Two samples, however, one from the parting 

shale and one from the upper shale, gave similar hydrogen 

index and oxygen index values of 70 mgHC/gTC~ and 

Organic Geochemical Studies of Metalliferous Parts of the Middle Proterozoic Nonesuch Formation 61 
Lu 

(f) 

<: 

0 

c.. 

(f) 

Lu 

a:: 

a:: 

0 

fl.) 

~ Lu 

Q 

IJ .II - -

13 

11 

it I 

IS 

16 

17 

RETENTION TIME 

IS 

j 

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19 

21 

23 

25 

'27 

:• J IJt 

29 

UP PER SHALE 

<non -mineralized 

lil'J I 

-

UPPER SHALE 

Thinly Shale stratum 

(mineralized) 

24 

Figure 2. Capillary gas chromatographs ofthe extractable hydrocarbons from 

a nonmetalliferous section of the upper shale (top) and of the total extractable 

material from a metalliferous section of the thinly shale (bottom). The upper 

shale chromatogram was kindly provided by L. Pratt, Indiana University. 

40-50 mgC02/gTOC, respectively (HC=hydrocarbons, 

TOC=total organic carbon). These indices are typical for 

thermally degraded algal organic matter. T max values of 

450-460 °C suggest, however, that the rocks were heated 

not much higher than the approximately 100 °C indicated by 

sulfide minerals (Brown, 1971) and fluid inclusion studies 

(Nishioka, 1983). The great age of these strata, not their 

thermal history, evidently is the major contributor to the 

moderate thermal maturity of the organic matter. 

The FfiR spectra of kerogen isolated from samples of 

the thinly shale and the lower sandstone show distinctive 

patterns for the two strata (fig. 3). Within each rock type, the 

FfiR patterns of different samples are similar, except that 

the spectra of the floatable kerogenous material isolated 

from the lower sandstone during mineral dissolution differ 

from those of the bulk kerogen. 

62 Metalliferous Black Shales and Related Ore Deposits 

The infrared spectral band at 1,644 cm-1

, most likely 

corresponding to aromatic C=C bond st~etching, is 

prominent in kerogen spectra from both the thinly shale and 

the lower sandstone. The spectral bands between wavenumbers 2,965 cm-1 and 2,850 cm-1

, corresponding to aliphatic 

C-H bond stretching of methylene and methy1 groups, are 

significant only in the spectra of kerogen fro'll the lower 

sandstone samples. These data imply that the bulk kerogens 

in these two strata have considerable aromat:r! character, 

with the kerogen from the lower sandstone being more 

aliphatic in character. 

The infrared spectra of the floatable low~r sandstone 

kerogens are characterized by strong aliphatic C-H bands 

and an absent or notably weaker aromatic C=C band. The 

highly aliphatic character of this material, t<'<!ether with 

petrographic evidence of pore-filling organic natter in the 
lJJ 

u 

z 

<( 

IIL: 

(f) 

z 

<( 

0::: 

IlJJ 

> 

I-

<( 

_J 

lJJ 

0::: 

~000 3600 3200 2800 2400 2000 1600 1200 800 400 

WAVENUMBER (em -l) 

Figure 3. Fourier transform infrared spectra of kerogen isolated from the 

thinly shale (top) and the lower sandstone (middle) and of floatable organic 

matter released by dissolution of the lower sandstone during kerogen isolation 

(bottom). 

lower sandstone strata, suggests that the floatable material 

may be the residue of petroleum that migrated through this 

sandstone layer. 

None of these spectra displays evidence of C=O bond 

stretching, and thus the kerogen of these samples probably 

contains few carbonyl-oxygen-containing functional 

groups. The broad bands centered around 3,450 cm-1 in all 

samples may contain significant information about the 

presence or absence of functional groups, but it is masked 

by the unavoidable infrared absorption by water in this part 

of the spectrum. 

SUMMARY 

Characterization of organic matter from metalliferous 

and nonmetalliferous parts of the Nonesuch Formation of 

northern Michigan provides inferences about the role of 

organic matter in ore formation. These characterizaf'Jns are 

summarized in table 2. Organic matter in the Wh~te Pine 

copper deposits probably has been degraded relative to 

noncupriferous parts of the formation. The lower concentrations of organic carbon and of solvent-ext~actable 

material in the mineralized samples are consistent '"ith the 

hypothesis that oxidation of organic matter occurrec during 

deposition of copper from metal-bearing solutions. The 

absence of a significant contribution of n-alkanes to the total 

extractable material and the aromatization of kerogen in 

mineralized rocks are additional support for this hyp'lthesis. 

Further investigations of how the amounts and t}pes of 

organic matter relate to the abundance and occurr~nce of 

copper-mineralized rocks are needed to ascertain whether 

organic matter was an active participant in the: redox 

precipitation of the ores in these rocks. 

Organic Geochemical Studies of Metalliferous Parts of the Middle Proterozoic Nonesuch Formaticr.-- 63 
Table 2. Summary comparison of organic-matter 

characteristics of metalliferous rocks from the Nonesuch 

Formation in the White Pine Mine and of 

nonmetalliferous rocks from outside the mine area 

Organic-matter 

parameter 

White Pine Mine Nonmelalliferous 

samples 

Total organic carbon 

Concentration .............. 0-0.5 percent 

Mean B 13c ...................... -33.00%0 

Extractable n-alkanes 

Total concentration ........... Depleted 

Chainlength distribution ....... Depleted 

samples 

0-2.8 percent 

-33.04%0 

Normal 

Oil-like pattern 

Acknowledgments.-We thank the White Pine 

Copper Company for allowing access to its property. Field 

work at White Pine was supported by a grant from Amoco 

Oil Company. We are grateful to W.C. Kelly for sharing 

with us his knowledge and understandings of the geologic 

setting. Rock-Eval analyses were kindly provided by J.G. 

Palacas, and L. Pratt shared her unpublished extractable 

organic matter information with us. This work has been 

supported, in part, by a grant from the U.S. National Science 

Foundation (EAR-8707353). 

REFERENCES CITED 

Barghoorn, E.S., Meinschein, W.G., and Schopf, J.W., 1965, 

Paleobiology of a Precambrian shale: Science, v. 148, 

p. 461-472. 

Brown, A.C., 1971, Zoning in the White Pine copper deposit, 

Ontonagon County, Michigan: Economic Geology, v. 66, 

p. 543-573. 

64 Metalliferous Black Shales and Related Ore Deposits 

Eglinton, G., Scott, P.M., Belsky, T., Burlingam~. A.L., and 

Calvin, M., 1964, Hydrocarbons of biological origin from a 

one-billion-year-old sediment: Science, v. 145, p. 263-264. 

Ensign, C.O., Jr., White, W.S., Wright, J.C., Patrick, J.L., Leone, 

R.J., Hathaway, D.J., Trammell, J.W., Fri•:ts, J.J., and 

Wright, T.L., 1968, Copper deposits in the No:1.esuch Shale, 

White Pine, Michigan, in Ridge, J.D., ed., Ore deposits of 

the United States 1933-1967 (Graton-Sabs Volume): 

American Institute of Mining, Metallurgy, and Petroleum 

Engineering, v. 1, p. 459-488. 

Hieshima, G.B., Zaback, D.A., and Pratt, L.M., 19r9, Petroleum 

potential of Precambrian Nonesuch Fonnation [abs.]: 

American Association of Petroleum Geologists Bulletin, 

v. 73, p. 363. 

Imbus, S.W., Engel, M.H., Elmore, R.D., and Zu"lberge, J.E., 

1988, The origin, distribution and hydrocarbon generation 

potential of organic-rich facies in the Nonesurh Formation, 

Central North American Rift System-A re~ional study: 

Organic Geochemistry, v. 13, p. 207-219. 

Kelly, W.C., and Nishioka, G.K., 1985, Precambrian oil inclusions 

in late veins and the role of hydrocarbot,s in copper 

mineralization at White Pine, Michigan: Ge')logy, v. 13, 

p. 334-337. 

Nishioka, G.K., 1983, Origin oflate veins in the Whit~ Pine copper 

deposit, northern Michigan: Ann Arbor, University of 

Michigan, M.S. thesis, 51 p. 

Ptmann, W., Hagemann, H.W., Merz, C., and Speczfk, S., 1988, 

Influences of organic material on mineralizaf,'ln processes 

in the Permian Kupferschiefer Formation, Po~and: Organic 

Geochemistry, v. 13, p. 357-363. 

Tissot, B.P., and Welte, D.H., 1984, Petroleum ti1rmation and 

occurrence (2nd ed.): Berlin, Springer Verlag, p. 177. 

White, W.S., 1971, A paleohydrologic model fo"' the mineralization of the White Pine copper depc~\t, northern 

Michigan: Economic Geology, v. 66, p. 1-13. 

Wiese, R.G., Jr., 1973, Mineralogy and geochenistry of the 

Parting Shale, White Pine, Michigan: Economic Geology, 

v. 68, p. 317-331. 
Organic Geochemical and Petrological 

Investigations of a Natural Reactor and 

Its Environs at Oklo, GabonA Pre I iminary Report 

By Bartholomew Nagy1

, Joel S. Leventhal 2, and F. Gauthier-Lafaye3 

Parts of the uraniferous ore deposits in the Early 

Proterozoic Francevillian Series at Oklo, Gabon, went 

critical at about 2 Ga and produced a number of natural 

fission reactors. The main uranium ore zone, which was 

only minimally metamorphosed, contains 0.1-1.0 percent 

uranium and is associated with migrated organic matter (bitumen) (Gauthier-Lafaye, 1986). High-grade ores contain 

20-60 percent U and also contain organic matter. The 

fission reaction originated in the high-grade ores where 

water acted as the moderator; the reactors shut down 

when the contained water was expelled (Naudet, 1978). 

This expulsion of high-temperature water under high pressure caused extensive hydrofracturing (similar to the 

petroleum industry's hydro-frac process) in the reactor 

zone, in the surrounding ore deposit, and in some adjacent rocks. Organic liquids derived from syngenetic kerogen by the action of water at elevated temperatures 

(through a process apparently analogous to hydrous pyrolysis) were injected into the fractures. Aqueous solutions 

were also injected into the fractures. Migration of the organic and the inorganic liquids into the fractures occurred 

at least twice during the early geological history of the 

uranium ore deposits and the surrounding sedimentary 

rocks. The new work reported here is the study of 

catagenesis-metagenesis, migration of organic matter, and 

mobilization of uranium daughter and fission products. 

Mobilization of uraniferous kerogen has been reported before; for example, at Cluff Lake, Canada (Leventhal and 

others, 1987), and Elliot Lake, Canada (Nagy, 1989). 

1 Laboratory of Organic Geochemistry, Department of Geosciences, 

University of Arizona, Tucson, Arizona 85721. 2

U.S. Geological Survey, Denver Federal Center, Box 25046, 

MS 973, Denver, Colorado 80225. 3

Centre National de Ia Recherche Scientifique, Centre de Sedimentologie et de Geochimie de Ia Surface, I, Rue Blessig, 67084 Strasbourg 

Cedex, France. 

The organic matter in a suite of samples (designated 

as KP3, Cro.336, Boy.33.FC, Boy.33.5, FB black shale, 

and LN-12; table 1) from Gabon was characterized in an 

attempt to define the possible retentivity of uraniun and 

its fission and daughter products by organic matter at and 

various distances from the natural reactors. These six 

samples are organic matter rich, containing 10-55 p~rcent 

organic carbon. One (KP3) is from the natural fc;osion 

reactor number 9 at Oklo, one (Cro.336) is fron the 

northern part of the Oklo deposit, two (Boy.33.FC and 

Boy.33.5) are from the nearby sandstone of the Boyindzi 

uranium deposit that did not go critical, and twc (FB 

black shale and LN-12) are not part of the deposh and 

are remote (50 and 25 km, respectively) from Oklo. 

Scanning electron microscopy (SEM) and semiquantitative energy-dispersive spectrometry (EDS) of the LI r and 

FB samples (figs. 1 and 2) revealed that they are, r~spectively, a bitumen having markedly conchoidal fra-;tures 

and a kerogenous siltstone. Subrounded and subangular 

quartz, pyrite, and clay minerals are the major components in the FB black shale. The original mineral t~~xture 

of the shale, which developed during deposition, is remarkably well preserved and was only minimally s ltered 

during subsequent diagenesis. Some of the round o:-- subrounded pyrite grains have hollow interiors. Rod~-Eval 

pyrolysis results for all these samples are typical of overmature organic matter and include very low hydrog~~n index (ill) values of 2-80 g hydrocarbons per gram total 

organic carbon and high Tmax of 472-604 °C. The oxygen 

index (01) values are 4-49. Surprisingly, all four of the 

uranium-rich samples have high 01 values. Three of them 

have the high HI values and have the lowest T max values. 

Stepwise pyrolysis-gas chromatography showed mainly 

gases for the Oklo uranium-rich samples (Cro.336, KP3). 

Organic matter from samples of the Boyindzi uraniu'll deposit (FC was an organic-rich separate of the bulk 

Investigations of a Natural Reactor 65 
sample) gave, in addition to gases, a suite of aromatic pyrolysis products containing as many as 12 carbon atoms. 

The samples away from the deposit showed mainly gases 

and some alkyl-substituted benzenes. Separate pyrolysisgas chromatography with coupled mass spectrometry 

showed, however, that all the samples have fairly similarmolecular signatures (but with varying abundances) of mainly 

alkyl-substituted, one and fused-ring aromatics, elemental 

sulfur and light gases such as carbon disulfide. Only the 

remote samples showed traces of n-alkanes. There were 

some differences between samples. In particular, the 

remote sample FB showed only CS2, benzene, toluene 

and xylenes, and perhaps indene, whereas, the sample 

from the reactor core (KP3) and both samples from Boyindzi (Boy.33.5 and 33.FC) gave more diverse pyrolysis 

products that also included naphthalene and mono- and 

dimethy !-substituted naphthalenes. The much lower hydrogen index of sample Cro.336 may account for its lack of 

fused-ring pyrolysis products. To explain these results we 

propose that, in addition to their syngenetic kerogen, the 

uranium-rich samples may contain two types of bitumen 

that were generated and migrated during diagenesis and 

the operation of the natural reactor and that subsequently 

were polymerized to a solid, in part by radiation damage. 

Laser Raman microspectroscopy of the samples gave two 

broad peaks at around 1,590-1,600 and 1,330-1,360 

cm-1

• The two remote samples (LN and FB) showed the 

best peak near 1,600 cm-1 (smallest width at half-height), 

probably because their very low uranium contents have 

little effect on disrupting the crystallinity. The two broad 

peaks, rather than a sharp one at 1,582 cm-1

, indicate that 

at least part of the organic matter is now cryptocrystalline 

graphite that has not yet matured to graphite of crystal 

size as large as 1 micrometer. Preliminary ICP-mass spectrometric studies of kerogen particles that have flat and 

globulelike shapes in the Boy.33.FC sample (5 km from 

Oklo) and of the kerogenous, whole-rock FB sample (50 

km southeast of Oklo) revealed only trace amounts of 

235U, 238U, 206Pb, 207Pb, and 208Pb in the latter but considerable abundances of these isotopes in the former. Our 

preliminary suggestion is that both fluid migration and organic matter may have affected the redistribution of uranium and other isotopes during syngenetic and epigenetic 

events. 

66 Metalliferous Black Shales and Related Ore Deposits 

Table 1. Summary of sample descriptions 

Sample Description 

KP3 ............. Part of the Natural Fission Reactor No.9. 

Sandstone has high uranium and organicmatter contents. Organic matter is black; 

majority of minerals are white ani have an 

ill-defined, pseudoflaky, fibrous 

morphology. 

Cro.336 ........ Sample from the northern part of the Oklo 

uranium deposit. Not part of Reactor No.9. 

Sandstone has high uranium and organicmatter contents. Contains disscrninated 

black organic particles and a 5-n'm-thick 

black layer of organic matter. 

Boy.33.FC .... 5 km from Oklo, at the Boyindzi ore deposit. 

Uranium-rich sandstone contains abundant, 

black organic globules more than 14 mm in 

diameter. 

Boy.33.5 ...... 5 km from Oklo, at the Boyindzi ore deposit. 

Sandstone has lower uranium cortent than 

Boy.33.FC. Contains organic globules 2-5 

mm in diameter. Euhedral quartz, yellow 

minerals, and white veins are vifible. 

LN-12 .......... 25 km from Oklo, in the district of Mounana. 

FB black 

Black, shiny, and brittle organic matter 

shows conchoidal fractures and contains no 

visible mineral inclusions. Prob1.bly a vein 

traversed by the drill core. 

shale .......... 50 km from Oklo, ncar Francev iJle. 

Kerogen-rich siltstone contains cnartz, clay 

minerals, and pyrite. 

REFERENCES CITED 

Gauthier-Lafaye, F., 1986, Les gisements d'uranium du Gabon et 

les reacteurs d'Oklo, Modele metallogeniq:,Ie de gites a 

fortes teneurs du Proterozoique inferieur: Menoire Sciences 

Geologiques, v. 78, p. 206. 

Leventhal, J.S., Grauch, R.I., Threlkeld, C.N., Lic~te, F.E., and 

Harper, C.T., 1987, Unusual organic matter a"~ociated with 

uranium from the Claude deposit, Cluff Lake, Canada: 

Economic Geology, v. 82, p. 1169-1176. 

Nagy, B., 1989, Some evolutionary pathways of metalliferous 

black shales and other fine-grained sediment&-Uraniferous 

kerogens at Witwatersrand, South Africa, Elliot Lake, 

Canada, and Oklo, Gabon, in Grauch, R.I., and Leventhal, 

J.S., eds., Metalliferous black shales and related ore 

deposit&-Program and abstracts: U.S. Geohgical Survey 

Circular 1037, p. 5-7. 

Naudet, R., 1978, Etude parametrique de la criticitt des reacteurs 

naturels, in Natural fission reactors: Intema~ional Atomic 

Energy Agency, Vienna, p. 589-600. 
0-184 NAGY 

0 

Figure 1. Backscattered scanning electron micrograph of sample LN-12 showing 

conchoidal fractures in the brittle organic matter. Sample is from a drill core and is 

probably part of a vein. Photograph from D.H. Krinsley, Department of Geology, 

Arizona State University, Tempe, Arizona. 

Figure 2. Backscattered scanning electron micrograph of the FB black shale 

sample. Quartz is gray in color, pyrite is white, and kerogen is black. Note clay 

minerals at the upper left part of the electron micrograph. Photograph from D.H. 

Krinsley, Department of Geology, Arizona State University, Tempe, Arizona. 

Investigations of a Natural Reactor 67 
Midcontinent Virgilian (Upper Pennsylvanian) 

Black Shales in Eastern Kansas 

By R.B. Schultz 1 and J.B. Maynard1 

Abstract 

Black shales, commonly metal rich, are distinct members 

of repetitive sequences of strata, referred to as megacyclothems, in the Midcontinent Virgilian. Four black shale 

members are present in the Shawnee Group and one black 

shale member is present in the Wabaunsee Group in eastern 

Kansas. Based on geochemical parameters including pyrite 

iron, pyrite sulfur content, acid-extractable iron content, 

percent total sulfur, and degree of pyritization (OOP), two 

types of black shales are present in the eastern Kansas 

Virgilian. 

Heebner-type black shales include the prototype Heebner Shale Member of the Oread Limestone, Queen Hill Shale 

Member of the Lecomption Limestone, and Larsh Shale and 

Burroak Shale Members of the Deer Creek Limestone. 

Shanghai Creek-type black shales include the prototype 

Shanghai Creek Shale Member of the Howard Limestone and 

Holt Shale Member of the Topeka Limestone. 

Geochemically, Heebner-type black shales contain 

more total sulfur (mean=0.75 percent) than the Shanghai 

Creek-type (mean=O.l 0 percent). The degree of pyritization is 

greater in the Heebner-type units (0.55) than .in the Shanghai 

Creek-type (0.15). Additionally, Heebner-type black shales 

contain more acid-extractable iron. 

Previously proposed black shale categories can also be 

related to depositional setting. Using DOP=0.45 as a boundary 

between aerobic and restricted conditions and DOP=0.75 as 

the distinction between restricted and inhospitable conditions, 

Heebner-type black shales are interpreted to have formed 

under restricted conditions and Shanghai Creek-type black 

shales under aerobic conditions. 

INTRODUCTION 

Upper Pennsylvanian black shales of the Midcontinent, which are commonly metalliferous, are present in 

carbonate-dominated Virgilian Series cyclic sequences 

1

University of Cincinnati, Department of Geology, Cincinnati, 

Ohio 45221-0013. 

68 Metalliferous Black Shales and Related Ore Deposits 

(fig. 1 ). These black shale units can be traced many miles in 

outcrops and in subsurface cores (Merriam, 1963 ). 

Characterized by prominent phosphate nodule development 

near the base of the unit, the black shales contain quartz, 

feldspars, calcite, dolomite, hematite, chlorite, kaolinite, 

illite, and various mixed-layer assemblages in various 

percentages (Schultz, 1987). Mixed terrestrial and marine 

organic matter make up as much as 30 percent of the units 

(Coveney and Glascock, 1989). 

Stratigraphically, the black shales make up part of the 

most stable and recurring elements of cyclic sequences and 

represent the transgressive phase of development. Heckel 

( 1977) offered a model for deposition of the black shales 

that envisions water becoming deep enough to develop a 

thermocline strong enough to prevent bottom oxygenation 

by wind-driven vertical circulation. Heckel's model for 

black shale deposition obviates the difficulty of explaining, 

in shallow tropical water, the combination of nonskeletal 

phosphate production and widespread uniformity of a quiet 

anoxic environment between two marine limestone units. A 

useful parameter in the discussion of black shale bottom 

conditions is the degree of pyritization (DOP), which has 

been advocated as a paleoenvironmental indicator of 

bottom-water oxygenation (Raiswell and others, 1988). The 

utilization of DOP forms the basis for this study of the 

bottom-water conditions of Upper Pennsylvanian black 

shales of the Midcontinent. 

Geologic Setting 

Throughout the Late Pennsylvanian, Kansas was 

covered by a shallow, subequatorial, epeiric sea (Heckel, 

1972). Sediment was deposited in broad north-trending 

synclinal structures (Cubitt, 1975). Local and external 

tectonic events affected the sedimentary succession and 

provided an influx of sediment. Structurally high areas 

(fig. 2) limited the areal extent of the epeiric sea and 

included the Amarillo, Arbuckle, and Wichita uplifts to the 

south, the Ancestral Rockies to the west, and the Ozark 

dome to the east (Merriam, 1986). 
a. wen :l ww Scranton 0 

~ -a:~ 

Shale C) a: w w 

+ .0 ~en t-

:l _.zCJ.) d en <<(> 

* 

X --CJ.) 0 (.) zZz Shanghai Creek Howard u. <( 

Shale Member Limestone 0 >>~ 

t 

as o...Jz 

Severy (/) a:>-< :.~-~~\:/·.. ·. · .. a.. en> Shale z d ::·.·.·.·-·-. zz_. 

~ ~:(_:\ · ..... · .. : cew~ Topeka _.a.z 

Holt Limestone -a:z 

Shale Member ~ww 

a: a. a. 

• -a. 

d >:::J 

+ Calhoun Shale 

Larsh 

and Burroak Deer Creek c. 

:l 

Shale Members Limestone 0 

~ 

t ~ 

Q) 

d Shale Q) 

~ c 

~ 

as 

Lecompton J: 

(/) 

Queen Hill Limestone 

Shale Member 

t 

d. 

Kanwaka 

Shale 

t 

Heebner 

Shale M ember Oread 

Figure 1. Generalized stratigraphic column of Virgil ian rocks in Kansas. Black shale members 

are depicted on the left; d denotes deltaic complex. Modified from Zeller (1968). 

The Ancestral Rockies developed in response to 

orogenic fluctuations during the Late Devonian to Early 

Pennsylvanian (Cubitt, 1975). Clastic sediments were shed 

into adjacent basins during the Late Pennsylvanian (Cubitt, 

1975). The Amarillo, Arbuckle, and Wichita uplifts, structurally associated with the Ouachita Mountains, may 

represent a continent-arc collision (Walper and Fowett, 

1973) that occurred early during the subsequent opening of 

the proto-Atlantic Ocean (Cubitt, 1975). Erosi<:ln of 

Amarillo, Arbuckle, and Wichita Mountain chains during 

the Pennsylvanian produced clastic materials that were 

deposited in the vicinity of the Kansas sea. The Ozar1· dome 

Black Shales in Eastern Kansar~ 69 
EXPLANATION 

Bshoreline 

~Uplands 

c=J Marine 

c.=..J Structural 

Elements 

\~ "--------... ,-,' .,., -- ' 

I ',, .................... ' /.~; --- I \ -,.. ,' \_,_ ·~--_.---,- ·----1 

DENVER I ,-,_: : I 

BASIN I 1-------. I I I I 

I 

II 

,' 

I'-... ,, 

..__. J ~: \1 I 

11~1 IL I~ 1 

1 Kansas 1 ' 1 I I \ 

{L ,_,, ------... , I :~" I \ --- \1 ', OUACHITA 

; /MOUNTAINS 

Figure 2. Tectonic features of the U.S. Midcontinent during Virgil ian time. 

Modified from Cubitt (1979). 

of east-central Missouri was a complex uplifted block of 

Precambrian crystalline igneous and Paleozoic sedimentary 

rocks. Channel sandstone deposits in the eastern Kansas 

Virgilian reflect the mineralogy of the Ozark region and are 

composed primarily of clay and silt (Cubitt, 1975). 

Thus, it is postulated that during the Late Pennsylvanian in eastern Kansas, the rise of the Ouachita Mountains 

resulted in deposition of a thick clastic sequence, and during 

rapid uplifts clastic wedges built onto the shelf region of 

Kansas. Sedimentary deposits formed in the Kansas epeiric 

sea during the Virgilian consist of limestone alternating 

with thin, calcareous marine shales (gray marine shales and 

black shales) (Heckel, 1972). These mainly marine 

packages are interlayed with thick clastic units deposited 

70 Metalliferous Black Shales and Related Ore Deposits 

from deltaic complexes from the Ouachita reghn and the 

lowlands north and east of Kansas (Heckel, 1972). Figure 1 

depicts the shale and limestone sequences. 

Shaw (1964) proposed that such epeiric seas rarely 

are deeper than 800 m and may have only been 130m deep. 

Slopes would have been less than 1 m per kilometer at the 

time of deposition. The epeiric sea was subjecte1 to global 

changes in sea level (Vail and others, 1977}, and minor 

fluctuations of sea level were superimposed on the overall 

sea level trend. According to Wanless (1972), at least 25 

separate transgressions and regressions are rec"'~gnized in 

the Virgilian. Pennsylvanian paleogeography, based on the 

presence of coals, evaporites, and dune-sand dep"'~Sits in the 

ancient trade wind belt, and paleomagnetic data imply that 
the Kansas sea was approximately 10° north of the 

paleoequator (Heckel, 1979). 

Sampling and Analytical Methodology 

Outcrop samples were collected from vertical 

channels along strike in eastern Kansas (fig. 3). The 

samples, representing the least weathered rock available, 

were collected on the basis of lateral and vertical changes in 

color, fauna, grain size, bedding, and other visible structures 

and characteristics. Subsurface cores from western and 

central Kansas (fig. 3), which provide a revealing look at 

unweathered black shale units, were sampled at appropriate 

intervals based on the characteristics previously mentioned. 

The subsurface core samples allow comparison of fresh 

outcrop samples with unweathered core samples of the same 

units and thus provide an indication of the amount and 

nature of weathering. The subsurface core samples also 

permit examination of the western lateral equivalents of the 

Forest City Basin sedimentary rocks (fig. 3). 

• 

• 

• J 

• • • • 

•• • • ~ 

, .. 

• • • 

I - •• 

l - • 

J •• 

I I ~J t 

7 

• 

• • • •• • • II l • 

Analytical techniques used in this study include ;r -ray 

fluorescence for major elements and several trace elerrl'!:nts, 

analysis of amount of total organic carbon (TOC), and 

colorimetric determination of acid-soluble iron to provide 

the DOP parameter. Degree of pyritization provides a quick 

and reliable quantitative method of characterizing bo+t.omwater oxygenation conditions during deposition but, 

according to Raiswell and others ( 1988), has several 

constraints. 

1. Appreciable organic carbon must be present 

(> 0.15 percent). 

2. Only fresh samples or subsurface core sanples 

can be used because loss of pyritic sulfur may occur rs the 

result of oxidation reactions. 

3. Sufficient clastic materials (that is, iron 

containing) must be present in the samples. Less thr11 65 

percent skeletal debris is suggested by Raiswell and B~mer 

(1985). 

4. Sediments that possess late diagenetic iror-rich 

concretionary carbonate material should be avoided. Iron 

migration adds to acid-extractable iron content. 

I ~ 

' ..___ \ 

~ ~- :'!'I ,....._ ~ • • ~ • ••• ..... • ~ 

• • • •• . 

•• .. • 

• • • 

• • '· • 

. .... • 

• ....,.., , . 

• Core samples 

f! .'F:e t=1. ~ Miles • Outcrop samples 

Figure 3. Outcrop (circles) and core (squares) sample localities, Kansas. 

Black Shales in Eastern Kansas 71 
...... 

N 

~ 

!!. 

!: 

;; 

.. 

Q 

c 

Cll 

~ = 

n 

:II:" 

VI 

I» =- Table 1. Major-element analyses of black shales from the Virgilian of Kansas ii" 

Cll [All values in weight percent except Zn, which is in parts per million. Samples designated HB, QH, and LB are Heebner type, those designated SH and HO are Shanghai Creek I» 

= type. Tr indicates trace) a. 

,;J 

ttl 

Sample AI203 Mn02 MgO CaO Na20 K20 s Zn20 3 ~ Si02 Ti02 Fe203 P20s 

a. OUTCROP SAMPLES 

0 

.. HB1 47.58 0.72 14.44 5.70 0.032 2.21 4.09 0.72 3.38 0.87 1.19 70 ttl HB2 55.43 0.90 16.70 6.08 0.039 2.24 0.77 0.91 3.45 0.27 0.02 68 0 

ttl HB3 52.54 0.84 18.53 5.40 0.030 2.15 1.27 0.83 3.34 0.14 0.95 1,292 "C 

Q 

Cll HB4 50.55 0.75 18.38 4.69 0.037 1.88 4.01 0.58 3.22 0.19 0.21 883 ::::;: 

QH1 46.26 0.64 12.46 5.08 0.029 2.40 2.59 0.57 3.21 0.80 1.62 3,714 Cll 

QH2 55.01 0.88 18.02 5.31 0.029 2.39 0.67 0.92 3.74 0.16 0.01 644 

QH3 45.99 0.68 12.98 4.86 0.026 1.96 3.95 0.66 3.10 0.77 0.86 1,116 

QH4 46.31 0.70 14.43 4.99 0.031 2.56 4.77 0.80 3.25 0.56 0.78 1,035 

QH5 50.46 0.85 21.19 6.43 0.028 2.16 1.06 0.46 3.89 0.13 Tr 106 

QH6 52.51 0.87 18.02 5.87 0.035 2.06 1.14 0.84 3.19 0.46 0.05 2,109 

LB1 46.16 0.81 14.83 6.40 0.027 1.94 1.68 0.56 3.50 0.39 0.88 1,196 

LB2 56.24 0.95 17.75 5.75 0.040 2.08 0.69 0.95 3.13 0.28 Tr 88 

LB3 44.87 0.78 14.84 6.08 0.029 2.27 1.81 0.70 3.81 0.40 1.06 1,606 

LB4 44.21 0.78 13.98 6.87 0.025 1.99 2.00 0.62 3.35 0.28 0.69 4,393 

H01 50.15 0.75 16.78 5.22 0.026 2.36 3.51 1.01 3.57 0.59 0.04 789 

SH1 49.29 0.84 18.67 6.13 0.033 2.35 1.54 0.77 3.66 0.26 1.44 94 

SH2 50.03 0.90 19.17 6.10 0.025 2.32 1.25 0.75 3.62 0.18 0.05 330 

SH3 50.59 0.90 18.69 6.54 0.049 2.37 1.50 1.17 3.34 0.47 0.03 2,155 

SH4 46.87 0.67 15.37 4.44 0.069 2.21 9.17 0.84 2.96 0.22 0.47 239 

Average 49.53 0.80 16.59 5.68 0.034 2.21 2.45 0.77 3.41 0.39 0.54 1154 
Table 1. Continued 

Sample Si02 Ti02 AI203 Fe

1

o3 Mn02 MgO CaO Na

20 K20 P205 s Zn203 

CORE SAMPlES 

HBC-1 26.86 0.16 4.37 0.65 0.022 2.46 45.77 0.61 1.76 1.00 0.20 217 

HBC-2 27.96 0.19 4.86 0.81 0.024 2.40 51.48 0.61 1.88 1.42 0.25 189 

HBC-3 25.13 0.16 4.60 0.79 0.024 2.65 39.86 0.71 1.83 1.40 0.24 173 

HBC-4 44.18 0.42 12.01 1.93 0.020 3.37 15.76 1.06 3.65 0.32 0.16 297 

HBC-5 44.24 0.46 12.79 1.99 0.020 3.37 15.00 1.10 3.87 0.20 0.12 232 

HBC-6 33.62 0.25 8.00 1.49 0.021 2.32 23.03 0.77 2.78 0.17 0.75 279 

HBC-7 19.91 0.12 3.60 0.52 0.019 1.29 28.49 0.34 1.58 0.14 0.16 Tr 

QHC-1 49.40 0.62 14.04 4.44 0.026 3.70 5.32 1.30 3.87 0.18 1.91 91 

QHC-2 49.18 0.64 14.22 4.68 0.026 3.72 5.35 1.28 3.92 0.16 1.99 116 

QHC-3 49.29 0.65 14.35 3.27 0.024 4.16 6.78 1.33 4.12 0.23 0.85 62 

QHC-4 46.80 0.57 13.89 2.71 0.019 4.26 5.00 1.35 4.15 0.46 0.53 62 

QHC-5 27.19 0.21 6.07 1.74 0.032 9.76 21.34 0.96 1.83 0.30 1.64 4 

QHC-6 37.09 0.49 11.25 3.51 0.034 7.22 12.40 2.01 3.02 1.84 2.57 32 

QHC-7 43.29 0.60 12.29 3.21 0.032 6.87 9.65 1.38 3.08 0.36 1.53 48 

QHC-8 45.27 0.66 13.35 3.50 0.030 7.51 7.63 1.56 3.19 0.49 1.76 52 

QHC-9 37.87 0.59 11.00 5.27 0.030 6.97 10.08 1.48 2.95 0.41 4.33 37 

SHC-1 39.44 0.42 11.17 2.43 0.037 2.39 18.02 1.04 2.94 0.15 0.82 22 

SHC-2 41.65 0.48 12.36 3.08 0.048 2.93 15.07 1.07 3.14 0.17 0.65 37 

SHC-3 43.65 0.53 13.41 3.07 0.036 2.68 13.56 1.15 3.37 0.16 0.85 40 

Average 38.53 0.43 10.40 2.58 0.030 4.21 18.40 1.11 3.00 0.50 1.11 93 

STANDARDS 

SD0-1 49.80 0.72 12.62 9.33 0.046 1.55 1.04 0.42 3.30 0.12 5.31 72 

= MAG-I 51.19 0.75 16.46 6.98 0.100 3.13 1.38 3.91 3.72 0.18 0.43 135 

i» SCo-1 63.39 0.62 13.70 5.22 0.050 2.76 2.64 0.95 2.82 0.22 0.07 105 n 

:11:" SGR-1 28.30 0.24 6.49 2.98 0.032 4.57 8.32 3.02 1.63 0.29 1.56 81 Vl 

0.54 10.15 7.50 0.037 1.25 0.84 0.34 2.65 0.09 4.27 61 ::T ST-10 59.66 e!.. 

~ 

Ill 

s· ST-11 68.97 0.41 7.80 5.77 0.028 0.96 0.64 0.26 2.04 0.07 3.28 51 m ST-12 79.26 0.28 5.21 3.85 0.019 0.64 0.43 0.17 1.36 0.05 2.19 41 ~ 

1i ST-13 89.73 0.14 2.59 1.91 0.009 0.32 0.21 0.09 0.68 0.02 1.09 31 

= 

~ 

Ill = 

~ 

..... 

(,;,) 
...... 

olloo 

~ tD 

i: 

~ ... 

0 

c 

Ill 

~ = 

n 

::a:" 

{ll 

::r Table 2. Iron, sulfur, and carbon in black shales from the Virgilian of Kansas Sll 

;- [Samples designated HB, QH, and LB are Heebner type, those designated SH and HOare Shanghai Creek type. Sorg (organic sulfur), TOC (total organic carbon), Fe2sol (ferrous Ill 

Sll iron), FeTsol (ferric iron), FePY (pyrite iron); Spy, pyrite sulfur or nonorganic sulfur. Tr indicates trace] ::I 

Q.. 

;1::1 

tD Sample Fe2sol FeTsoi+FePY 

~ number %Fe %S %Sorg %TOC Fc2sol FeTsol FePY Spy DOP FeTsol %Fe Spy/TOC Q.. 

OUTCROP SAMPLES 0 

... 

tD QH1 5.04 1.61 0.11 15.00 0.49 0.73 1.31 1.51 0.64 0.66 0.41 0.100 

0 SHl 6.13 1.44 0.03 4.74 0.98 1.45 1.23 1.41 0.46 0.67 0.44 0.297 tD 

"C HB1 5.70 1.19 0.06 8.80 0.70 1.44 0.98 1.13 0.41 0.49 0.43 0.128 0 

Ill 

:::.- LB3 6.08 1.06 0.11 16.12 0.69 1.28 0.83 0.95 0.39 0.54 0.36 0.059 Ill 

HB3 5.40 0.95 0.02 2.18 0.78 1.32 0.81 0.93 0.38 0.59 0.40 0.429 

QH3 4.86 0.86 0.11 16.37 0.64 1.18 0.65 0.75 0.36 0.54 0.40 0.046 

QH4 4.99 0.78 0.08 11.19 0.87 1.30 0.61 0.70 0.32 0.67 0.39 0.063 

LB1 6.40 0.88 0.11 15.23 0.81 1.75 0.67 0.77 0.28 0.46 0.39 0.051 

SH4 4.44 0.47 0.01 1.40 1.03 1.58 0.40 0.46 0.20 0.65 0.45 0.329 

LB4 6.87 0.67 0.13 18.41 0.89 2.09 0.47 0.54 0.18 0.43 0.39 0.030 

HB4 4.69 0.21 0.03 3.58 0. 71 1.56 0.16 0.18 0.09 0.45 0.38 0.052 

QH6 5.87 0.05 0.02 2.28 1.22 2.59 0.03 0.03 0.01 0.47 0.46 0.015 

HOI 5.22 0.04 0.01 2.06 0.44 1.96 0.02 0.03 0.01 0.23 0.39 0.012 

SH2 6.10 0.05 0.03 3.72 0.55 1.93 0.02 0.02 0.01 0.29 0.33 0.006 

HB2 6.08 0.02 0.01 0.93 0.37 1.09 0.01 0.01 0.01 0.34 0.19 0.015 

SH3 6.54 0.03 0.02 2.52 0.96 2.47 0.01 0.01 0.00 0.39 0.39 0.005 

QH2 5.31 0.01 0.01 1.00 0.81 1.57 0 0 0 0.52 0.30 0.003 

QH5 6.43 Tr 0.00 0.27 0.25 2.49 0 0 0 0.10 0.39 0 

LB2 5.75 Tr 0.00 0.06 0.19 2.61 0 0 0 0.07 0.61 0 

Average 5.68 0.54 0.05 6.62 0.70 1.70 0.43 0.49 0.20 0.41 0.40 0.075 
Table 2. Continued 

Sample Fe2sol FeTsoi+FePY 

number %Fe %5 %Sorg %TOC Fe2sol FeTsol FePY s~~ DOP FeTsol %Fe S~y/TOC 

CORE SAMPLES 

QHC-1 4.44 1.91 0.03 3.83 0.44 0.72 1.64 1.88 0.70 0.61 0.53 0.492 

QHC-9 5.28 4.37 0.01 1.22 0.39 1.68 3.80 4.36 0.69 0.23 1.02 3.575 

QHC-2 4.67 1.99 0.03 4.00 0.57 0.85 1.71 1.96 0.67 0.68 0.54 0.491 

QHC-6 3.52 2.60 0.01 0.96 0.35 1.33 2.26 2.59 0.63 0.26 1.01 2.701 

QHC-5 1.77 1.65 0.00 0.20 0.31 0.87 1.44 1.65 0.62 0.36 1.33 8.243 

HBC-6 1.51 0.73 0.01 1.35 0.25 0.50 0.63 0.72 0.56 0.51 0.80 0.534 

QHC-8 3.49 1.76 0.00 0.34 0.40 1.16 1.53 1.76 0.57 0.35 0.76 5.169 

QHC-7 3.21 1.53 0.00 0.31 0.35 1.06 1.33 1.53 0.56 0.33 0.74 4.928 

QHC-3 3.27 0.84 0.01 1.20 0.39 0.64 0.72 0.83 0.53 0.60 0.42 0.693 

SHC-1 2.43 0.81 0.00 0.01 0.38 0.75 0.71 0.81 0.49 0.50 0.61 

QHC-4 2.72 0.51 0.00 0.18 0.25 0.50 0.44 0.51 0.47 0.50 0.36 2.826 

SHC-3 3.07 0.83 0.01 1.16 0.41 0.82 0.72 0.82 0.47 0.51 0.51 0.709 

HBC-7 0.58 0.13 0.00 0.32 0.09 0.28 0.11 0.13 0.29 0.32 0.94 0.399 

SHC-2 3.07 0.62 0.00 0.26 0.55 1.03 0.54 0.62 0.34 0.54 0.52 2.378 

HBC-1 0.70 0.16 0.00 0.59 0.45 0.50 0.14 0.16 0.21 0.90 1.00 0.264 

HBC-2 0.86 0.22 0.00 0.71 0.29 0.50 0.19 0.22 0.27 0.58 0.97 0.303 

HBC-3 0.83 0.20 0.00 0.64 0.22 0.47 0.17 0.20 0.27 0.47 0.94 0.306 

= HBC-4 1.94 0.13 0.00 0.01 0.19 0.48 0.11 0.13 0.19 0.41 0.34 

~ HBC-5 2.01 0.08 0.00 0.07 0.22 0.40 0.07 0.08 0.15 0.54 0.27 1.136 ~ Average 2.60 1.11 0.01 0.91 0.34 0.76 0.96 1.10 0.56 0.50 0.72 1.212 V) 

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Col1bration curve for XRF regression analys1s of sulfur standards. 

Figure 4. Calibration curves for XRF regression analyses. A, 

Iron standards. B, Sulfur standards. 

Analytical Techniques 

The equipment employed for the X-ray fluorescence 

analysis consisted of a wavelength-dispersive Rigaku 

System 3070 X-ray spectrometer. Samples were initially 

76 Metalliferous Black Shales and Related Ore Deposits 

ground in a shatterbox for 5-7 minutes (or until approximately 400 mesh). Samples were not sieved in order to 

avoid preferential mineralogical effects. The resulting 

powder was then pressed into a pellet usin ~ 20 tons of 

pressure. The base of the pellets consists of mi~rocrystalline 

cellulose, which allows for ease of handling and chemical 

stability and provides a nonreactive, scq}inonporous 

medium. Sample analyses were repeated three times each on 

the Rigaku System for major element oxide w~ight percent. 

It was essential that iron and sulfur analyses l'a. accurate in 

order for the DOP determinations to be preci ~e • 

Each sample in this study was analyzed for Si, Ti, AI, 

Fe, Mn, Mg, Ca, Na, K, P, and S (table 1). Calibration 

curves for each element were generated using several 

geochemical standards including MQSB--1, SD0-1, 

MAG-1, SCo-1, and SGR-1. The calibration curves for 

iron and sulfur are depicted on figure 4. 

Analysis of total organic carbon (Toe: was accomplished by using a Perkin-Elmer Model 240 Elemental 

Analyzer and SD0-1 as a standard. Samples were crushed 

and analyzed for total carbon, then treated with concentrated 

HCI to remove carbonate carbon. Residue f~om the acid 

treatment was analyzed for total organic crrbon content 

(TOC). 

In addition to the analysis for TOC, a colorimetric 

determination for acid-soluble iron was conducted on 

powder samples to satisfy the equation for D~P (Raiswell 

and Berner, 1985): 

DOP=Pyrite iron/(HCl-extractable iron+pylite iron) (1) 

Acid-extractable iron was obtained by boiling each 

sample in concentrated HCI for precisely 1 minute on a hot 

plate (Berner, 1970). This treatment extracts the most 

reactive iron compounds and is readily reproducible. 

Dissolved iron was determined by the 1,10 phenanthroline 

colorimetric method using a Beckman Model DU-2 spectrophotometer (Liu, 1988). Both total and ferrous acidsoluble iron were measured. 

The colorimetric method is based on the principle that 

"reactive" iron is dissolved into solution by boiling with 

HCI and then complexed with 1,10 phenand, .. oline at pH 

values of 3.2-3.3. The orange-red complex that results 

obeys Beer's Law where its intensity is indepa.ndent of pH 

(3-9) and is stable for a substantial amount of time. The 

phenanthroline reacts only with ferrous iron; ferric iron is 

determined by reduction using hydroxylamine hydrochloride followed by the phenanthroline rer~tion. Pyrite 

iron was estimated by assuming that all sulfur is present as 

pyrite or organic sulfur. Organic sulfur was estimated from 

organic carbon by using ratios determined by Kaplan and 

others (1963) for Santa Barbara Basin sedim~nts. Because 

some sulfur may also be present as sulfate, tl'iS procedure 

provides a maximum value for pyrite iron and thus for DOP. 
RESULTS AND TYPES OF BLACK 

SHALES IN THE KANSAS SECTION 

Based on geochemical parameters, including pyrite 

iron, total sulfur content, acid-extractable iron, and DOP, 

two types of black shales are present in the Virgilian of 

Kansas (table 2). Results for outcrop samples differ slightly 

from results for core samples. Core samples generally 

contain less total iron and more calcium and sulfur. 

Maximum DOP was calculated using equation 

( 1) and by assuming stoichiometric iron in pyrite calculated 

from total sulfur content corrected for organic sulfur. 

Raiswell and others (1988) defined depositional environmental conditions based on DOP values and concluded that 

DOP values of less than 0.45 indicate aerobic bottom-water 

conditions, values between 0.45 and 0.75 define restricted 

bottom-water conditions, and values greater than 0.75 

reflect inhospitable bottom-water conditions. Based on this 

classification scheme, Heebner-type units and Shanghai 

Creek-type units of the Kansas Virgilian differ 

dramatically. 

Heebner-Type Black Shales 

Heebner-type black shales, as coined by Coveney 

(1985), include the Heebner Shale Member of the Oread 

Limestone, Queen Hill Shale Member of the Lecompton 

Limestone, and Larsh Shale and B urroak Shale Members of 

the Deer Creek Limestone (fig. 1). From a geochemical 

perspective, the Heebner types contain more total sulfur 

(mean=0.75 percent) than the Shanghai Creek types 

(mean=0.1 0 percent), undoubtedly the result of differing 

depositional settings for the two units. DOP values 

(mean=0.55) are also greater for the Heebner-type 

restricted conditions. 

Shanghai Creek-Type Black Shales 

Shanghai Creek-type black shales, named for the 

Shanghai Creek Shale Member of Merriam (1989) include 

the prototype Shanghai Creek Shale Member of the Howard 

Limestone and the Holt Shale Member of the Topeka 

Limestone (fig. 1). Characterized by their lower total sulfur 

content, acid-extractable iron content, and DOP values, the 

Shanghai-type black shales were probably deposited in 

shallower water than the Heebner-type rocks and thus could 

accommodate organic material not associated with the 

Heebner-type rocks. DOP values are considerably lower 

(mean=0.15) and are consistent with aerobic conditions as 

defined by Raiswell and others ( 1988). 

CONCLUSIONS 

Black shales, commonly metal rich, make up distinct 

members of repetitive sequences in the Virgilian of Kansas. 

Five black shale members were analyzed for various geochemical parameters including acid-extractable iron co'ltent 

and major-element contents. Based on these and other 

geochemical and sedimentological characteristics, two 

types of black shales are present in the Virgilian of Ka,sas: 

the Heebner and the Shanghai Creek. Degree of pyritiz1-tion 

(DOP) was used to infer bottom-water oxygenation conditions during deposition. DOP values for Heebner-type 

deposits are, on average, 0.55 (restricted conditi 'lns ), 

whereas DOP values for Shanghai Creek-type units are 0.10 

(aerobic conditions). 

Acknowledgments.-The author would like to thank 

Dr. D.F. Merriam for offering helpful suggestions, ec1;ting 

the manuscript, and stimulating interest in the project. 

Additionally, thanks go to Dr. R.M. Coveney and Dr. 

H.L.O. Huyck for their helpful suggestions. Numerous 

discussions with Dr. Huyck greatly improved the manuscript. Core samples were provided with the help o.f Dr. 

W.L. Watney and the Kansas Geological Surve;' in 

Lawrence, Kansas. This project represents research for part 

of a doctoral thesis funded in part by a Grant-in-Aid from 

Sigma Xi and a Research Grant from the Geological Scdety 

of America (4547-90). 

REFERENCES CITED 

Berner, R.A., 1970, Sedimentary pyrite formation: American 

Journal of Science, v. 268, p. 1-23. 

Coveney, R.M., Jr., 1985, Temporal and spatial variations in 

Pennsylvanian black shale geochemistry, in Watney, W.L., 

Kaesler, R.L., and Newell, K.D., eds., Proceedings Recent 

Interpretations of Late Paleozoic cyclothems: Law~ence, 

Kansas, Kansas Geological Survey, p. 247-266. 

Coveney, R.M., Jr., and Glascock, M.D., 1989, A review of the 

origins and metal-rich Pennsylvanian black shales, central 

U.S.A., with an inferred role for basinal brines: Applied 

Geochemistry, v. 4, no. 4, p. 342-367. 

Cubitt, J.M., 1975, A computer analysis of the geochemistry and 

mineralogy together with the petrology of the Upper 

Pennsylvanian and Lower Permian shales of Kansas, 

U.S.A.: England, University of Leicester, Ph.D. thesis, 

366 p. 

__ 1979, The geochemistry, mineralogy, and petrolo~y of 

Upper Paleozoic shales of Kansas: Kansas Geol,'>gical 

Survey Bulletin Number 217, 117 p. 

Heckel, P.H., 1972, Pennsylvanian stratigraphic reefs in Kansas, 

some modem comparisons and implications: Geologische 

Rundschau, v. 61, no. 2, p. 584-598. 

__ 1977, Origin of phosphatic black shale fad~s in 

Pennsylvanian cyclothems of Mid-Continent North 

America: American Association Petroleum Geolology 

Bulletin, v. 61, no. 4, p. 1045-1068. 

Heckel, P.H., and others, 1979, Field guide to Pennsylnmian 

cyclic deposits of Kansas and Nebraska: Kansas Geol 1gical 

Survey Guidebook Series 4, p. 4-60. 

Kaplan, I.R., Emery, K.O., and Rittenberg, S.C., 1963. The 

distribution and isotopic abundance of sulphur in recent 

Black Shales in Eastern Kansas 77 
marine sediments off southern California: Geochimica et 

Cosmochimica Acta, v. 27, p. 297-331. 

Liu, T., 1988, C-S-Fe correlation of shales hosting sedimentary 

manganese deposits: Ohio, University of Cincinnati, Ph.D. 

thesis, 300 p. 

Merriam, D.F., 1963, The geologic history of Kansas: Kansas 

Geological Survey Bulletin 162, 317 p. 

___ 1986, Geology of the Shawnee Group (Virgilian Stage, 

Upper Pennsylvanian) in eastern Kansas and its relation to 

the cyclothem theory, in Merriam, D.F., ed., Stratigraphic, 

sedimentologic, and cyclic relationships of the Shawnee 

Group (Virgilian, Pennsylvanian) in eastern Kansas: Kansas 

Geological Society Annual Field Conference, 38th, 

Guidebook, p. 1-52. 

___ 1989, The Wauneta Limestone, a new member of the 

Howard Limestone (Wabaunsee Group, Upper Pennsylvanian) in eastern Kansas: Kansas Academy of Science 

Transactions, v. 92, nos. 1-2, p. 107-112. 

Raiswell, R., and Berner, R.A., 1985, Pyrite formation in euxinic 

and semi-euxinic sediments: American Journal of Science, 

v. 285, p. 710-724. 

Raiswell, R., Buckley, F., Berner, R.A., and Anderson, T.F., 1988, 

Degree of pyritization of iron as a paloeonvironmental 

78 Metalliferous Black Shales and Related Ore Deposits 

indicator of bottom-water oxygenation: Journal of Sedimentary Petrology, v. 58, no. 5, p. 812-819. 

Schultz, R.B., 1987, Mineral determination of the Heebner Shale 

Member (Shawnee Group, Upper Pennsylva'lian) in southeastern Kansas X-ray diffraction techniques: The Compass, 

v.64,no. 3,p. 149-159. 

Shaw, A.B., 1964, Time in stratigraphy: New York, McGraw-Hill, 

365 p. 

Vail, P.R., Mitchum, R.M., and Thompson, S., III, 1977, Seismic 

stratigraphy and global changes of sea level, pt. 4--Global 

cycles of relative changes of sea level, in Pa;•ton, C.E., ed., 

Seismic stratigraphy to hydrocarbon deposition: American 

Association of Petroleum Geology Memoir 26, p. 83-98. 

Walper, J.L., and Rowett, C.L., 1973, Plate tectonic:<> and origin of 

Carribean Sea and Gulf of Mexico: Oklah':lma Geologic 

Notes, v. 33, no. I, p. 21-22. 

Wanless, H. R., 1972, Eustatic shifts in sea leY~l during the 

deposition of Late Paleozoic sediments b the Central 

United States, in Elam, J.G., and Chuber, S.P , eds., Cyclic 

sedimentation in the Permian Basin: West Te;'{~S Geological 

Society, p. 41-54. 

Zeller, D.E., ed., 1968, The stratigraphic successhn in Kansas: 

Kansas Geological Survey Bulletin 189, 81 p. 
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INTERNATIONAL GEOLOGICAL CORRELATION 

PROGRAM PROJECT 254 

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AMOCO 

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AUTHOR INDEX 

Bloomstein, E.I ............................................................................................ 1 Huyck, H.L.O ............................................................................................ 42 

Breit, G.N .................................................................................................... 6 Leventhal, J.S ...................................................................................... 12, 65 

Chen Nansheng ............................................................................................ 9 Lyons, T.W ................................................................................................ 51 

Clark, J.B ..................................................................................................... ! Mauk, J.L ................................................................................................... 59 

Coveney, R.M., Jr ........................................................................................ 9 Maynard, J.B .............................................................................................. 68 

Desborough, G.A ....................................................................................... 12 Meyers, P.A. , ............................................................................................. 59 

Gauthier-Lafaye, F ..................................................................................... 65 Nagy, 8 ...................................................................................................... 65 

Giordano, T.H ............................................................................................ 31 Schultz, R.B ............................................................................................... 68 

Hatch, J .R .................................................................................................. 12 Tuttle, M.L ................................................................................................... 6 

Ho, E.S ....................................................................................................... 59 Wanty, R.B .................................................................................................. 6 

AUTHOR INDEX 85 



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

which show geology as interpreted from aerial photographs. Series also 

includes maps of Mars and the Moon. 

Coal Investigations Maps are geologic maps on to':lOgraphic or 

planimetric bases at various scales showing bedrock or s·,rlicial geology, stratigraphy, and structural relations in certain coal-rFource areas. 

Oil and Gas Investigations Charts show stratigraphic information 

for certain oil and gas fields and other areas having petrole·m potential. 

Miscellaneous Field Studies Maps are multicolor <'r black-andwhite maps on topographic or planimetric bases on qwW8ngle or irregular areas at various scales. Pre-1971 maps show bed"\.-,ck geology 

in relation to specific mining or mineral-deposit probleJr~~ post-1971 

maps are primarily blaclc-and-white maps on various sutiects such as 

environmental studies or wilderness mineral investigati<m~. 

Hydrologic Investigations Atlases are multicolored or black-andwhitemaps on topographic or planimetric bases presentini a wide range 

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

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

catalogs 

Permanent catalogs, as well as some others, givini comprehensive listings of U.S. Geological Survey publications are av,.ilable wtder 

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

and Open-File Reports Section, Federal Center, Box 25A25, Denver, 

CO 80225. (See latest Price and Availability List.) 

"Publlcatlons of the Geological Survey, 1879-1961tr may be purchased by mail and over the counter in paperbaek book ~""tm and as a 

set of microfiche. 

"Publications of the Geological Suney, 1962- 1970" may be purchased by mail and over the counter in paperback book {i"111l and as a 

set of microfiche. 

"Publications of the U.S. Geological Survey, 1971-1~1" may be 

purchased by mail and over the counter in paperback bo<-'1( form (two 

volumes, publications listing and index) and as a set of mi-Tofiche. 

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

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

over the counter in paperback book form. 

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

Water-Supply Reports and Maps For(State)," may bepurc11 ased by mail 

and over the counter in paperback booklet form only 

"Price and A vallabllity List of U.S. Geological Sun·~y Publlcations," issued annually, is available free of charge in pape:rback booklet form only. 

Selectedcoplesofamonthlycatalog"NewPublicatior~oftheU.S. 

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

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

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

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

National Center, Reston, VA 22092. 

Note.-Prices of Government publications listed in ol~~ catalogs, 

announcements, and publications may be incorrect. Th ~fore, the 

prices charged may differ from the prices in catalogs, ann<'~mcements, 

and publications. 
Grauch and Huyck-METALLIFEROUS BLACK SHALES, ORE DEPOSITS-PROCEEDINGS, 1989-U.S. Geological Survey Circular 1058