Contributions to Commodity 

Geology Research 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 
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Contributions to Commodity 

Geology Research 

JOHN ·H. DeYOUNG, Jr., and JANE M. HAMMARSTROM, 

editors 

Introduction 

By John H. DeYoung, Jr. 

A. Barite-A Model for Deposition from Stratified Seawater Based on Barite Nodules in Paleozoic Shale 

and Mudstone of the Appalachian Basin 

By Sandra H.B. Clark 

· B. Barite-A Comparison of Grades and Tonnages for Bedded Barite Deposits with and without 

Associated Base-Metal Sulfides 

By Greta J. Orris 

C. Gold-Distribution of Gold in Porphyry Copper Deposits 

By Dennis P. Cox and Donald A. Singer 

D. Mercury-An Important Byproduct in Epithermal Gold Systems 

By James j. Rytuba and Chris Heropoulos 

E. Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites in Southern Oregon 

and Northern California 

By Michael P. Foose 

F. Platinum-Group Elements-Occurrences in the Bethlehem Porphyry Copper Deposits, Highland Valley, 

British Columbia 

By Norman J Page, Joseph A. Briskey, and Leung Mei 

G. Platinum-Group Elements-Occurrences in Gold Deposits in Nevada, Oregon, and Idaho 

By Norman J Page, William C. Bagby, Raul J, Madrid, and Barry C. Moring 

H. Sand and Gravel-An Enormous Offshore Resource within the U.S. Exclusive Economic Zone 

By S. Jeffress Williams 

I. Tungsten-Geology and Resources of Deposits in Southeastern China 

By James E. Elliott 

J. Tungsten-Grades and Tonnages of Some Deposits 

By W. David Menzie, Gail M. Jones, and James E. Elliott 

K. Vanadium-Resources in Fossil Fuels 

By George N. Breit 

This volume is published as chapters A-K. These chapters are not available separately 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 
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 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1992 

For sale by 

Book and Open-File Report Sales 

U.S. Geological Survey 

Box 25425 

Denver, CO 80225 

Library of Congress Cataloging in Publication Data 

Contributions to commodity geology research. 

(U.S. Geological Survey bulletin ; 1877) 

Bibliography: p. 

Supt. of Docs. no. : I 19.3:1877 

1. Geology, Economic. 2. Mines and mineral resources. I. DeYoung, John H., 

Jr. II. Hammarstrom, jane Marie. Ill. Series. IV. Series: U.S. 

Geological Survey bulletin ; 1877. 

QE75.B9 no. 1877 557.3 s [553] 88-600424 

[TN260] 
CONTENTS 

[Letters designate the chapters] 

Introduction, by John H. DeYoung, Jr. 

(A) Barite-A Model for Deposition from Stratified Seawater Based on Barite 

Nodules in Paleozoic Shale and Mudstone of the Appalachian Basin, by Sandra 

H.B. Clark 

(B) Barite-A Comparison of Grades and Tonnages for Bedded Barite Deposits with 

and without Associated Base-Metal Sulfides, by Greta J. Orris 

(C) Gold-Distribution of Gold in Porphyry Copper Deposits, by Dennis P. Cox and 

Donald A. Singer 

(D) Mercury-An Important Byproduct in Epithermal Gold Systems, by James J. 

Rytuba and Chris Heropoulos 

(E) Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing 

Laterites in Southern Oregon and Northern California, by Michael P. Foose 

(F) Platinum-Group Elements-Occurrences in the Bethlehem Porphyry Copper 

Deposits, Highland Valley, British Columbia, by Norman J Page, Joseph A. 

Briskey, and Leung Mei 

(G) Platinum-Group Elements-Occurrences in Gold Deposits in Nevada, Oregon, and 

Idaho, by Norman J Page, William C. Bagby, Raul J. Madrid, and Barry C. 

Moring 

(H) Sand and Gravel-An Enormous Offshore Resource within the U.S. Exclusive 

Economic Zone, by S. Jeffress Williams 

(I) Tungsten-Geology and Resources of Deposits in Southeastern China, by James 

E. Elliott 

(J) Tungsten-Grades and Tonnages of Some Deposits, by W. David Menzie, Gail 

M. Jones, and James E. Elliott 

(K) Vanadium-Resources in Fossil Fuels, by George N. Breit 

Volume Contents Ill 

Introduction 

By john H. DeYoung, Jr. 

What is commodity geology? It is defined here as the 

application of geologic science to the understanding of the 

geologic and economic aspects of resources of mineral 

commodities. The research results contributed to this bulletin provide some examples of the variety of geologic 

approaches to mineral-resource research. As an introduction 

to these studies, the following brief historical perspective on 

commodity geology is presented. 

Some understanding of mineral-resource distribution 

in North America was a goal of early explorers who came to 

the New World with a mandate to search for gold and other 

precious metals. When the United States was founded and 

started to experience economic growth, concern about 

mineral resources and other raw materials became a concern 

of the Government. In 1833, geologist G.W. Featherstonhaugh wrote to the Secretary of War to recommend that "a 

geological chart, upon which all the metallic and mineral 

resources of each of the States should be accurately delineated, would be a labor productive of great advantages to 

the nation, and would be well received by it" (Featherstonhaugh, 1833, p. 5). 

These ideas on a map of geology and mineral deposits 

were an early recognition of the importance of geologic 

science in national materials policy. In 1879, following a 

recommendation by the National Academy of Sciences, 

Congress combined the activities of four Territorial Surveys, which had been directed to explore the Western 

United States, into the U.S. Geological Survey (USGS). 

The USGS was charged to classify the public lands and to 

examine the geological structure, mineral resources, and 

products of the national domain. 

Commodity geology became the essential role of 

geologists in the USGS Division of Mineral Resources; 

these geologists also collected statistics on production and 

resources of minerals for the annual publication "Mineral 

Resources of the U.S." In 1925, responsibility for the 

publication of "Mineral Resources of the U.S." (today's 

"Minerals Yearbook") and the attendant statistical collection was transferred to the Bureau of Mines (USBM), which 

had been established in 1910 (National Research Council, 

1982, p. 129-131). Since that time, USGS commodity 

Manuscript approved for publication September 28, 1988. 

geologists have teamed up with commodity specialists in 

the USBM for several important studies of the national 

mineral position. Examples include the 1948 book "Mineral 

Resources of the United States" (USBM and USGS, 1948) 

and the basic report on Reserves and Potential Resources for 

the Paley Commission (President's Materials Policy Commission, 1952). Resource information from USGS geologists is a regular contribution to the annual publication of 

"Mineral Commodity Summaries" by the USBM. 

Geologic studies of mineral resources, including 

descriptive and quantitative models of mineral deposits, 

research concerning the genesis and geologic setting of 

deposits, the distribution of elements among earth materials, and the investigation of possibilities for occurrence of 

undiscovered mineral resources continue to be important 

responsibilities of the USGS. Summaries of the geology and 

resources of mineral and energy commodities were published in 1973 in a benchmark USGS Professional Paper 

titled "United States Mineral Resources" (Brobst and Pratt, 

1973). More recently, USGS work on models of mineraldeposit types has been published in a single volume, 

"Mineral Deposit Models," with 87 deposit models that 

include data from over 3, 900 mineral deposits around the 

world (Cox and Singer, 1986). 

Results of the diverse types of research included 

under the rubric of commodity geology are often abstracted 

in compendium-type publications, but more complete 

accounts of these studies are published in a variety of 

scientific journals and technical report series. This bulletin 

assembles several examples of commodity geology 

research. These examples do not comprehensively cover the 

range of geologic research applications to mineral commodity problems, but they do offer a sampling or flavor of the 

diversity of important questions about resource occurrences, questions that underlie frequently expressed concerns about minerals availability. 

Four general research approaches are represented by 

the 11 papers. Two of these approaches are based on models 

of mineral-deposit types. Genetic models of mineral deposits offer interpretations of the geologic origin of deposits, 

thus making regional geologic history an important factor in 

predicting areas where undiscovered resources might occur. 

This type of genetic deposit model research is represented 

Introduction 
by the studies of Clark (barite) and Rytuba and Heropoulos 

(mercury). Quantitative models of the size of mineral 

deposits (grade and tonnage models) are constructed from 

the collection and analysis of statistics from well-explored 

deposits. The methods used in these studies can be applied 

in estimating the size of undiscovered resources in geologically favorable areas and in comparing the importance of 

different geologic mineral-deposit types in analyzing possibilities for mineral supply. Grade and tonnage model 

approaches are used in the papers by Orris (barite)~ Cox and 

Singer (gold); and Menzie, Jones, and Elliott (tungsten). 

Descriptive accounts of the regional distribution of 

mineral commodities are a traditional economic geology 

approach to resource analysis. The reports of Williams 

(sand and gravel offshore the United States) and Elliott 

(tungsten in southeastern China) are representative of this 

type of study. 

Less traditional, but of increasing importance as 

mineral production from certain conventional deposit types 

declines, is the study of different modes of occurrence for 

mineral commodities, either as different or lower grade 

deposit types having the sought-after commodity as a main 

product or as a potential byproduct in deposits of other 

minerals. Four examples of this type of research are 

presented here-Foose (nickel in laterites); Page, Briskey, 

and Mei (platinum-group elements in porphyry copper 

deposits)~ Page, Bagby, Madrid, and Moring (platinumgroup elements in gold deposits); and Breit (vanadium in 

fossil-fuel deposits). 

Concerns about the adequacy of future mineral supplies stimulate inquiry into mineral resources, but these 

concerns are not universally shared. For instance, the 33 

specialists who constituted a Unesco Advisory Panel on 

Science, Technology and Society in the early 1980's were 

in large part optimistic about production and use of 

resources. They believed that inequities in population 

growth and resource availability could be ameliorated by 

"mandates." Two geologists at a 1986 Dahlem Workshop 

on Resources and World Development had a more supportive view of mineral-resource research, regarding ''the issues 

2 Contributions to Commodity Geology Research 

of resource abundance and availability to be of vital 

importance to societal health," and concluding that 

inequities cannot be resolved "without major efforts to do 

so." (McLaren and Skinner, 1987, p. 1). In addition, some 

lessons· of that Dahlem Workshop serve to temper the 

expectations that may be created by the title of this bulletin: 

All problems connected with resources and the 

environment involve many disciplines in science, 

technology, and socioeconomics; all issues are 

multifaceted and none is the prerogative of a single 

group of specialists. 

Science and technology can discover, describe 

and assess resources and the distribution of 

resources can be outlined, but scientists and 

technologists can say distressingly little about the 

economic viability of future resources. (Mclaren and 

Skinner, 1987, p. 3.) 

REFERENCES 

Brobst, D.A., and Pratt, W.P., eds., 1973, United States mineral 

resources: U.S. Geological Survey Professional Paper 820, 

722 p. 

Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: 

U.S. Geological Survey Bulletin 1693, 379 p. 

Featherstonhaugh, G. W., 1833, Letter dated January 12, 1833, to 

Lewis Cass, Secretary of War, in Public documents of the 

Senate of the United States, 22d Congress, 2d Session, v. I, 

document 35, p. 5-7. 

McLaren, D.J., and Skinner, B.J., 1987, Introduction, in 

McLaren, D.J., and Skinner, B.J., eds., Resources and 

world development: Chichester, England, John Wiley and 

Sons, p. 1-12. 

National Research Council, Committee on National Statistics, 

1982, A review of the statistical program of the Bureau of 

Mines: Washington, D.C., National Academy Press, 210 p. 

President's Materials Policy Commission, 1952, Resources for 

freedom, v. II, The outlook for key commodities: 

Washington, D.C., U.S. Government Printing Office, 210 p. 

[U.S.] Bureau of Mines and [U.S.] Geological Survey, 1948, 

Mineral resources of the United States: Washington, D.C., 

Public Affairs Press, 212 p. 
Chapter A 

Barite-A Model for Deposition from 

Stratified Seawater Based on Barite Nodules 

in Paleozoic Shale and Mudstone of the 

Appalachian Basin 

By SANDRA H.B. CLARK 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract Al 

Introduction Al 

Characteristics of the Nodules Al 

Geologic Setting and Paleoenvironment A2 

Discussion A3 

References Cited AS 

FIGURES 

1. Map of the Eastern United States showing where barite nodules have been found in 

rocks of the Appalachian basin A2 

2. Generalized stratigraphic sections for barite-nodule localities A3 

3. Eh-pH diagram for the system Ba-S-H20 A4 

4. Model for the formation of barite from stratified water AS 

Contents Ill 

Barite-A Model for Deposition from Stratified 

Seawater Based on Barite Nodules in Paleozoic Shale 

and Mudstone of the Appalachian Basin 

By Sandra H.B. Clark 

Abstract 

Barite nodules occur in Ordovician and Devonian 

shales and mudstones of the Appalachian basin at numerous localities. Characteristics of some nodules, such as 

those having alternate layers of concentric calcite and 

barite, suggest that the nodules formed during early 

diagenesis as chemical conditions varied. Comparison of 

lithologies and environments of deposition at several 

localities suggests that these barite nodules formed at or 

near times of maximum sea level in mostly stagnant, 

oxygen-deficient marine environments and in association 

with calcareous and pyritic concretions. Some barite nodules occur in strata that record dysaerobic bottom conditions, which are between lithologies that represent aerobic and anaerobic bottom conditions. The characteristics 

of the nodules and enclosing shale and mud rock suggest 

that variations in Eh and pH conditions associated with the 

margins of anoxic seawater could result in the precipitation of barium from pore waters of the sediments. 

Although not enough barium is present in normal seawater to allow formation of significant amounts of barium 

precipitate, anoxic seawater of low to normal pH can 

contain substantial dissolved barium. Barite that reached 

deeper anoxic waters, possibly through the marine biological cycle, could dissolve and be concentrated at margins of anoxic water bodies. The model for concentration 

of barite from anoxic seawater at reduction-oxidation 

interfaces provides a feasible alternative to models that 

show barium derived from submarine-exhalative sources 

or other forms of hydrothermal fluids. 

INTRODUCTION 

Occurrences of barite in marine sedimentary rocks are 

widespread, and in some areas the accumulations are thick 

enough to constitute economically important bedded or 

stratiform barite deposits. In some deposits, for example 

those in Nevada and Arkansas, barite is dominant; in others, 

for example Meggen in Germany and Ballynoe in Ireland, 

barite is peripheral or laterally gradational into base-metal 

deposits. Because of possible economic significance, barite 

in marine sedimentary rocks is of interest as a potential 

indicator of associated stratiform deposits. A study of barite 

nodules in several localities from Ordovician and Devonian 

shale and mudstone of the Appalachian basin has led to a 

model of how barite could have been deposited from 

seawater in a stratified water body without introduction of 

barium from hydrothermal sources such as submarine 

springs. The objective of this paper is to present this model 

as a feasible alternative explanation for the occurrence of 

barite in marine shale and mudstone in the absence of 

evidence for submarine-exhalative activity. 

I thank Eric R. Force, Wallace de Witt, Jr., Frank R. 

Ettensohn, Michael P. Cecile, Kevin L. Shelton, Walter E. 

Dean, Laurence M. Nuelle, and Forrest G. Poole for 

valuable comments and suggestions; Elizabeth E. Good for 

editing; and Sylvia M. Heinrich and Karen L. Cinsavich for 

assisting in the fieldwork. 

CHARACTERISTICS OF THE NODULES 

Barite nodules have been reported from Middle 

Ordovician shales in Tennessee, from Lower to Middle 

Devonian shales in Virginia, West Virginia, and Pennsylvania, and from Upper Devonian shales in New York 

(Carpenter and Fagan, 1969; de Witt, 1974; Way and 

Smith, 1983; Pepper and others, 1985; Nuelle and Shelton, 

1986) (fig. 1). 

The nodules commonly consist of acicular, bladed 

crystals oriented radially to a small central mass of equant 

barite crystals. Nodules of this type, called rosettes, may be 

hollow in the core and generally contain interstitial clay and 

other impurities in increasing amounts from core to rim. 

Another common type of nodule is composed of unoriented, 

irregularly shaped barite crystals in which clay fills interstices. Many of the nodules are spherical or oblate and 

commonly coalesce into irregular bulbous masses. The 

barite nodules are associated with pyritic concretions or 

with calcareous nodules and concretions or both at many 

localities. Laminae in the enclosing shale or mudstone 

Barite-A Model for Deposition from Stratified Seawater A 1 
_. Upper Devonian 

e Middle and Lower 

Devonian 

0 Middle Ordovician 

N 

0 100 200 MILES 

I 1

1 I 1

1 11 I 

0 100 200 KILOMETERS 

Figure 1. Places in the Eastern United States where barite 

nodules have been found in rocks of the Appalachian 

basin. 

curve conformably around the nodules in little-deformed 

areas. Concentric calcareous and barite layers alternate in 

concretions, some of which are more than 12 em in 

diameter, near Williamsville, Bath County, Va. Barite also 

fills shrinkage fractures in barite nodules as well as in 

septarian pyritic and calcareous concretions. Calcite, pyrite, 

and sphalerite are associated with barite in some of the 

fracture-filling veinlets. 

Barite rosettes occur along bedding in mudstone and 

shale, which are compacted around the rosettes, near Silver 

Creek, Chautauqua County, N.Y. Barite fills the chambers 

of a large undeformed fossil cephalopod, and barite rosettes 

occur in a surrounding calcareous nodule (Pepper and 

others, 1985). The barite rosettes in the carbonate nodule 

are similar in size and form to rosettes in the main body of 

the rock. 

The symmetric compaction of laminae around nodules, the association of barite with carbonate and pyrite, and 

the fact that barite fills chambers of undeformed fossils 

enclosed in calcareous nodules suggest that the barite 

A2 Contributions to Commodity Geology Research 

formed early in diagenesis in response to slight fluctuations 

in reduction-oxidation potential and pH during development. 

GEOLOGIC SETTING AND 

PALEOENVIRONMENT 

Barite nodules in the western part of Virginia occur in 

the Lower to Middle Devonian Needmore Shale (fig. 2A), 

which represents prodeltaic deposition (Dennison, 1971) in 

a basin deep enough to restrict vertical circulation (Ettensohn and Barron, 1981). The shale and mudstone associated 

with the barite nodules in the Needmore Shale near Clifton 

Forge, Alleghany County, Va., were deposited in a basin of 

stratified stagnant water from water having different oxygen 

contents. Shale beneath the barite-nodule zone is dark gray 

to grayish black, fissile, carbonaceous, and mostly nonfossiliferous except for rare imprints of Lingula, suggesting 

deposition in an anaerobic environment. Barite nodules are 

in light- to medium-gray, olive-gray or yellowish-gray 

mudstone that contains sparse pelagic fossils (styliolinids 

and tentaculitids) and no benthic fossils. The lack offissility 

in the mudstone in contrast to the fissility of the underlying 

and overlying shales is probably the result of bioturbation. 

This mudstone probably formed under dysaerobic conditions. Overlying the zone of barite nodules is light- to 

medium-gray and olive-gray silty mudstone containing 

abundant fossils, including several species of brachiopods, 

ostracods, and trilobites in addition to pelagic forms. This 

part of the section accumulated in oxidized water although 

still in a rather restricted deep-water facies. Barite nodules 

occur near Williamsville, Va., in a similar but less complete 

sequence and extend into the base of the highly fossiliferous 

aerobic zone. Geochemical profiles show slight enrichment 

of manganese, nickel, and cobalt in matrix shale of the 

dysaerobic and aerobic zones relative to those of the 

anaerobic zone and the opposite pattern for lead and silver 

(Clark and Mosier, 1989). 

Barite nodules also occur in shales overlying the 

Needmore Shale (fig. 2A) that contain calcareous concretions and lenses: the Purcell Member of Cate (1963) of the 

Marcellus Shale in West Virginia, Maryland, and Pennsylvania (de Witt, 1974; Way and Smith, 1983; Nuelle and 

Shelton, 1986), the Chittenango Member of the Marcellus 

Shale in New York, beds containing calcareous concretions 

in the Millboro Shale in Virginia, and the Tully Limestone 

Member of the Harrell Shale in West Virginia (Nuelle and 

Shelton, 1986). Matrix shales for the barite nodules associated with calcareous lenses and concretions are mostly 

nonfossiliferous, fissile, carbonaceous, and pyritic and 

probably formed in anaerobic to dysaerobic environments. 

Barite nodules near Silver Creek in western New 

York formed in a similar setting (Pepper and others, 1985). 

They occur mostly in the lower part of the Upper Devonian 
A B 

SERIES FORMATION 

SERIES FORMATION MEMBER 

UPPER Brallier 

DEVONIAN 

c 

LITHOLOGY 

SERIES FORMATION 

LITHOLOGY 

~ Black 

shale 

~ 

Ha"ell !·· .. ·. 

South Wales Gray 

mudrock, 

shale 

Perrysburg Athens 

Dunkirk 

MIDDLE 

ORDOVI- bd 0 UPPER ClAN ~ 

[ )::: 

0 DEVONIAN Hanover 

::8 Java 

MIDDLE ~ .. DEVONIAN Pipe Creek 

Sandstone, 

siltstone, 

shale 

LOWER 

DEVONIAN 

West 

Falls Angola 

LOWER 

ORDOVI-

[

30m 

Om 

ClAN 

Lenoir 

Mascot 

Limestone, 

~ 

dolomite 

00 

Calcareo us 

concretions 

Barite * 

nodules 

Figure 2. Generalized stratigraphic sections for barite-nodule localities: A, In Virginia, West Virginia, Maryland, 

Pennsylvania, and central New York; B, In western New York; C, In southern Virginia and Tennessee. 

Hanover Shale Member of the Java Formation, although 

some are present in the South Wales Member of the 

overlying Perrysburg Formation (fig. 2B). The Hanover 

Shale Member, like the South Wales Member, is composed 

predominantly of gray mudrock that contains many calcareous concretions and nodules. It overlies a thin, fissile, 

black shale, the Pipe Creek Shale Member of the Java 

Formation. Similarly, the South Wales Member overlies a 

predominantly black-shale unit, the Dunkirk Shale Member 

of the Perrysburg Formation. The depositional setting was 

prodeltaic, and mud accumulated in a low-energy reducing 

environment. 

Barite nodules in northeastern Tennessee and southem Virginia occur in the lower part of the Middle Ordovician Athens Shale (Carpenter and Fagan, 1969) (fig. 2C). 

The Athens Shale, which is predominantly dark gray to 

black, fissile, carbonaceous, and pyritic, probably formed 

in an anaerobic environment. It overlies the Lenoir Limestone, and nodular beds of limestone are locally interbedded 

in the lower part of the Athens Shale but are not present in 

all the barite-nodule localities. 

Comparison of the lithologies containing barite nodules and their paleoenvironments shows that a common 

characteristic is nodule formation in shale and mudstone 

that were deposited in mostly anaerobic to dysaerobic 

environments in basinal prodeltaic settings. Some localities 

yield evidence of variation in reduction-oxidation potential 

in stratified waters; barite nodules occur in lithologies that 

were deposited under dysaerobic water columns, stratigraphically between lithologies formed under aerobic and 

anaerobic conditions. The barite-nodule zone may either 

underlie or overlie black shale. In other localities, barite is 

associated with carbonate nodules in dark-gray to black 

shale, suggesting that there may have been a local increase 

in pH that effected both the precipitation of calcium 

carbonate from solution (Blome and Albert, 1985) and the 

precipitation of barium sulfate to form nodules. The Devonian units in which the barite nodules occur represent 

sedimentation during or near maximum marine transgression (Johnson and others, 1985; Dennison, 1986). 

Evidence for hot spring or other forms of hydrothermal activity such as feeder or fracture zones, crosscutting 

mineralization, or alteration has not been seen in the areas 

studied. 

DISCUSSION 

Several mechanisms have been suggested for barite 

formation in a marine environment. Submarine springs or 

exhalations are thought to be the source of barium in many 

deposits (Cecile and others, 1983; Brobst, 1984; Papke, 

1984; Nuelle and Shelton, 1986). Connate brine and ground 

water have been suggested as fluids that transported barium 

to sites of precipitation on the sea floor (Hanor and Baria, 

1977; Nuelle and Shelton, 1986). Deposition of barite in a 

sequence of carbonate rocks in northeastern British Columbia was attributed to mixing of anoxic seawater with 

meteoric ground water near the seaward edge of a coastal 

aquifer (Morrow and others, 1978). Miller and others 

Barite-A Model for Deposition from Stratified Seawater A3 
( 1977) proposed sedimentary models for precipitation of 

barite in an anoxic environment; the models were based on 

studies of the organic fraction from black, bedded-barite 

samples. The possibility of biogenic concentration of barite 

was discussed by Shawe and others (1969). Puchelt (1967) 

suggested that barite may precipitate directly from seawater 

during evaporation when the volume of seawater is reduced 

to between one-third and one-fifth of its original volume, 

corresponding to the last stages of carbonate deposition and 

the initial stages of calcium sulfate precipitation. 

Barite has been reported from deep-sea sediments in 

many localities (Dean and Schreiber, 1978). Although most 

is microcrystalline, locally nodules, rosettes, lenses, and 

laminae are common. Hydrothermal activity associated 

with rift zones was proposed as a source of the barium 

(Revelle and Emery, 1951; Arrhenius and Bonatti, 1965) as 

were biogenic processes (Church, 1979). Dean and 

Schreiber (1978) proposed that barite had a diagenetic 

origin at contacts between oxidizing and reducing environments and that the main source of barium was oxidation of 

organic matter. 

The characteristics of the barite nodules described in 

this paper and their paleoenvironmental setting suggest that 

they formed by slow growth during diagenesis at or near 

reduction-oxidation interfaces in a stratified water column 

or locally near areas of increased pH. 

Although barite is relatively insoluble under oxidizing conditions, it is fairly soluble in reducing conditions 

(fig. 3). Eh and pH values in the field of barite solubility 

can occur either within sediment on the sea floor with 

anoxic pore waters, or within anoxic seawater. With an 

increase in Eh or pH, or both, precipitation of barium 

sulfate and calcium carbonate would be predicted. 

Barium introduced into seawater from hot springs 

could precipitate in the vicinity of the vent if the Eh of the 

water were in the stability range for sulfate (Cecile and 

others, 1983). In this situation, thick deposits of barite 

might form. A submarine spring venting into anoxic seawater would result in precipitation of sulfides near the vent 

and sulfates and oxides farther away at sites where the 

anoxic waters abut oxidized water. Although introduction 

of barium from submarine springs is a feasible mechanism 

to explain large accumulations of bedded barite and barite 

associated with stratiform submarine-exhalative base-metal 

deposits, the occurrence of barite nodules, lenses, and 

laminae can be explained by other models that do not 

involve introduction of barium in hydrothermal fluids or 

connate brines. In addition to the mechanisms discussed by 

other researchers, precipitation from anoxic water is a 

possibility that should be considered. 

Although barium is undersaturated by a factor of 

about one-half in normal seawater (Church and Wolgemuth, 

1972), barium can be concentrated in waters having the 

compositional range of anoxic seawater, as mentioned 

above. The geologic relations of barite nodules in the 

A4 Contributions to Commodity Geology Research 

Eh 

1.0.-------------~--------------------~ 

0.8 

0.6 

0.4 

0 

-0.2 

-0.4 Water 

unstable 

Water 

unstable 

-0.6L-----~------~----~-------L------~ 

0 2 4 6 8 10 

pH 

Figure 3. Eh-pH diagram for the system Ba-S-H20 at 25 °C; 

1 atmosphere total pressure; and total dissolved sulfur 

species=10-1 • Adapted from Schmitt (1962). The shaded 

area is the field of soluble Ba; the long arrow (from 

Cannon and Force, 1983) shows the change in Eh-pH 

conditions of water from the Black Sea going from deep 

anoxic bottom water to oxidized surface water. 

Appalachian basin show that reduction-oxidation interfaces 

are indeed loci of barite-nodule formation. Barium may also 

be concentrated at interfaces with waters of slightly 

increased pH in anoxic zones, thus providing an explanation 

for the association of barite with calcareous and pyritic 

nodules in dark-gray to black carbonaceous shale. 

Concentration of barium by organisms is well known. 

Bowen ( 1956) reported barium concentrations ranging from 

450 to 4,400 times that in seawater in a wide variety of 

marine organisms. Observations of Chow and Goldberg 

(1960), Arrhenius and Bonatti (1965), Dean and Schreiber 

(1978), and Church (1979) show that involvement of 

organisms can be important in barite formation. 

A model for the concentration of barite from anoxic 

seawater shown in figure 4 is proposed to explain features 

in the barite-nodule localities described above. The model is 
Depth (m) 

Bioturbation; 

trace fossils; 

may contain pelagic 

fossils; benthic 

epifauna absent 

LITHOLOGY 

Calcareous, 

gray, olivegray or 

yellowishgray 

mudstone 

to shale 

------------------------~--------~ 

No bioturbation; 

pelagic fossils 

only. Laminated 

organic-rich 

mud 

Fissile, 

pyritic, 

carbonaceous, 

dark-gray 

to black 

shale 

Figure 4. Model for the formation of barite from stratified water. Model of stratified water adapted from Rhoads and 

Morse (1971), Byers (1977), Ettensohn and Barron (1981), and Ettensohn (1985). 

similar and related to the "bathtub ring" model for the 

formation of shallow marine sedimentary manganese deposits (Cannon and Force, 1983; Force and Cannon, 1988). 

Eh-pH relations suggest that barite precipitates at lower 

levels of oxidation than do manganese oxides; thus, barite is 

more likely to precipitate in the dysaerobic facies than are 

manganese oxides. However, the Eh-pH relations also 

suggest that barite might be associated with manganese 

carbonates, and, indeed, the association of barite with some 

manganese deposits has been noted by Force and Cannon 

(1988). The pattern of enrichment of trace amounts of 

manganese along with cobalt, zinc, and nickel (which could 

be adsorbed on manganese oxides) in the shale and mudstone in barite nodule zones in western Virginia also 

supports the suggestion of the relation between barium and 

manganese deposition (Clark and Mosier, 1989). 

In the absence of independent evidence of a submarine exhalative or other hydrothermal source for barium, I 

suggest the following origin: Barite nodules, layers, or 

laminae in shales or mudstones that formed at or near times 

of maximum sea level in dysaerobic to aerobic zones of 

basins of stratified water or that are associated with carbonate concretions or lenses in anaerobic to dysaerobic zones 

could have resulted from precipitation of barium dissolved 

in anoxic pore water. 

REFERENCES CITED 

Arrhenius, Gustaf, and Bonatti, Enrico, 1965, Neptunism and 

vulcanism in the ocean, in Sears, Mary, ed., Progress in 

oceanography, v. 3: New York, Pergamon Press, p. 7-22. 

Blome, C.D., and Albert, N.R., 1985, Carbonate concretionsAn ideal sedimentary host for microfossils: Geology, v. 13, 

p. 212-215. 

Bowen, H.J.M., 1956, Strontium and barium in sea water and 

marine organisms: Marine Biology Association (United 

Kingdom) Journal, v. 35, p. 451-460. 

Brobst, D.A., 1984, The geologic framework of barite resources: 

Institution of Mining and Metallurgy Transactions, sec. A, v. 

93, p. A123-A130. 

Byers, C. W., 1977, Biofacies patterns in euxinic basins-A 

general model: Society of Economic Paleontologists and 

Mineralogists Special Publication 25, p. 5-17. 

Cannon, W.F., and Force, E.R., 1983, Potential for high-grade 

shallow-marine manganese deposits in North America, in 

Shanks, W.C., III, ed., Cameron volume on unconventional 

mineral deposits: New York, American Institute of Mining, 

Metallurgical and Petroleum Engineers, Society of Mining 

Engineers, p. 175-189. 

Carpenter, R.H., and Fagan, J.M., 1969, Barite nodules in the 

Athens Shale in northeastern Tennessee and southwest Virginia: Southeastern Geology, v. 10, no. 1, p. 17-29. 

Cate, A.S., 1963, Lithostratigraphy of some Middle and Upper 

Devonian rocks in the subsurface of southwestern Pennsylvania: Pennsylvania Topographic and Geological Survey, 

General Geology Report G39, p. 229-240. 

Cecile, M.P., Shakur, M.A., and Krouse, H.R., 1983, The 

isotopic composition of western Canadian barites and the 

possible derivation of oceanic sulphate 834S and 8180 age 

curves: Canadian J oumal of Earth Sciences, v. 20, no. 10, p. 

1528-1535. 

Chow, T.J., and Goldberg, E.D., 1960, On the marine geochemistry of barium: Geochimica et Cosmochimica Acta, v. 20, p. 

192-198. 

Church, T.M., 1979, Marine barite, in Bums, R.G., ed., Marine 

minerals: Mineralogical Society of America Short Course 

Notes, v. 6, p. 175-209. 

Church, T.M., and Wolgemuth, Kenneth, 1972, Marine barite 

saturation: Earth and Planetary Science Letters, v. 15, no. 1, 

p. 35-44. 

Barite-A Model for Deposition from Stratified Seawater AS 
Clark, S.H.B., and Mosier, E.L., 1989, Barite nodules in Devonian shale and mudstone of western Virginia: U.S. Geological Survey Bulletin 1880, 30 p. 

Dean, W.E., and Schreiber, B.C., 1978, Authigenic barite, Leg 

41 Deep Sea Drilling Project, in California University, 

Scripps Institution of Oceanography, La Jolla, Initial reports 

of the Deep Sea Drilling Project, v. XLI: Washington, D.C., 

National Science Foundation, p. 915-931. 

Dennison, J.M., 1971, Petroleum related to Middle and Upper 

Devonian deltaic facies in the Central Appalachians: American Association of Petroleum Geologists Bulletin, v. 55, p. 

1179-1193. 

---1986, Devonian sea-level curve for Virginia and West 

Virginia compared with eustatic curve of Johnson, Klapper, 

and Sandberg (1985): Geological Society of America 

Abstracts with Programs, v. 18, no. 3, p. 218. 

de Witt, Wallace, Jr., 1974, Geologic map of the Beans Cove and 

Hyndman quadrangles and part of the Fairhope quadrangle, 

Bedford County, Pennsylvania: U.S. Geological Survey Miscellaneous Investigations Series Map I-801, scale 1:24,000. 

Ettensohn, F .R., 1985, Controls on development of Catskill Delta 

complex basin-facies, in Woodrow, D.L., and Sevon, W.D., 

eds. , The Catskill Delta: Geological Society of America 

Special Paper 201, p. 65-77. 

Ettensohn, F.R., and Barron, L.S., 1981, Depositional model for 

the Devonian-Mississippian black shales of North AmericaA paleoclimatic-paleogeographic approach, in Roberts, 

T.G., ed., GSA Cincinnati '81 field trip guidebooks, v. 2: 

Falls Church, Virginia, American Geological Institute, p. 

344-361. 

Force, E.R., and Cannon, W.F., 1988, Depositional model for 

shallow-marine manganese deposits around black shale 

basins: Economic Geology, v. 83, p. 93-117. 

Han or, J. S. , and Baria, L. R. , 1977, Controls on the distribution of 

barite deposits in Arkansas, in Stone, C.G., ed., Symposium 

on the geology of the Ouachita Mountains, v. 2: Little Rock, 

Arkansas Geological Commission, p. 42-49. 

A6 Contributions to Commodity Geology Research 

Johnson, J.G., Klapper, Gilbert, and Sandberg, C.A., 1985, 

Devonian eustatic fluctuations in Euramerica: Geological 

Society of America Bulletin, v. 96, no. 5, p. 567-587. 

Miller, R.E., Brobst, D.A., and Beck, P.C., 1977, The organic 

geochemistry of black sedimentary barite-Significance and 

implications of trapped fatty acids: Organic Geochemistry, v. 

1, p. 11-26. 

Morrow, D.W., Krouse, H.R., Ghent, E.D., Taylor, G.C., and 

Dawson, K.R., 1978, A hypothesis concerning the origin of 

barite in Devonian carbonate rocks of northeastern British 

Columbia: Canadian Journal of Earth Sciences, v. 15, p. 

1391-1406. 

Nuelle, L.M., and Shelton, K.L., 1986, Geologic and geochemical evidence of possible bedded-barite deposits in Devonian 

rocks of the Valley and Ridge province, Appalachian Mountains: Economic Geology, v. 81, p. 1408-1430. 

Papke, K.G., 1984, Barite in Nevada: Nevada Bureau of Mines 

and Geology Bulletin 98, 125 p. 

Pepper, J.F., Clark, S.H.B., and de Witt, Wallace, Jr., 1985, 

Nodules of diagenetic barite in Upper Devonian shales of 

western New York: U.S. Geological Survey Bulletin 1653, 

11 p. 

Puchelt, Harald, 1967, Zur Geochemie des Bariums im exogenen 

Zyklus: New York, Springer-Verlag, 205 p. 

Revelle, Roger, and Emery, K.O., 1951, Barite concretions from 

the ocean floor: Geological Society of America Bulletin, v. 

62, p. 707-724. 

Rhoads, D.C., and Morse, J.W., 1971, Evolutionary and ecologic 

significance of oxygen-deficient marine basins: Lethaia, v. 4, 

p. 413-428. 

Schmitt, H.H., ed., 1962, Equilibrium diagrams for minerals at 

low temperature and pressure: Cambridge, Massachusetts, 

Geological Club of Harvard, 199 p. 

Shawe, D.R., Poole, F.G., and Brobst, D.A., 1969, Newly 

discovered bedded barite deposits in East Northumberland 

Canyon, Nye County, Nevada: Economic Geology, v. 64, 

no. 3, p. 245-254. 

Way, J.H., and Smith, R.C., II, 1983, Barite in the Devonian 

Marcellus Formation, Montour County: Pennsylvania Geology, v. 14 no. 1, p. 4-9. 
Chapter B 

Barite-A Comparison of Grades and 

Tonnages for Bedded Barite Deposits with 

and without Associated Base-Metal Sulfides 

By GRETA j. ORRIS 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract Bl 

Introduction B 1 

Geologic Setting Bl 

Grade-Tonnage Data B2 

Summary B3 

References Cited BS 

FIGURES 

1-3. Graphs showing inverse cumulative frequency plots of: 

1. Grades for 30 bedded barite deposits B4 

2. Deposit tonnage for 30 bedded barite deposits B4 

3. Contained barite for 30 bedded barite deposits BS 

TABLES 

1. Bedded barite deposits used for grade and tonnage models B3 

2. Summary statistics for bedded barite grade, tonnage, and contained barite B4 

Contents Ill 

Barite-A Comparison of Grades and Tonnages for 

Bedded Barite Deposits with and without Associated 

Base-Metal SuI fides 

By Greta J. Orris 

Abstract 

Bedded barite mineralization may occur in distinct 

deposits or in deposits intimately associated with stratiform base-metal sulfide deposits that occur in a similar 

geologic environment. Analysis of grade, tonnage, and 

contained barite from the two styles of bedded barite 

mineralization shows that they can be treated as a single 

deposit type for the purpose of estimating barite 

resources. 

INTRODUCTION 

Basic geologic and descriptive data were collected for 

93 deposits classified as bedded or stratiform barite deposits 

in the geologic literature; the majority of these data have 

been released as a U.S. Geological Survey Open-File 

Report (Orris, 1985). Many of the major deposits in this 

classification, including Meggen, West Germany (Krebs, 

1981), and Ballynoe, Ireland, the barite deposit associated 

with the Silvermines base-metal deposit (Taylor and 

Andrew, 1978), are associated with stratiform zinc-lead 

sulfide mineralization. Other deposits, recently the dominant producers of barite, are not spatially associated with 

base-metal sulfides (Brobst, 1984). These latter deposits 

include all the known bedded deposits in the Nevada bedded 

barite belt of Papke (1984) and deposits in Arkansas, the 

Cuddapah district of India, and some of the deposits in the 

Selwyn Basin of the Canadian Yukon. 

Previous work (Singer and others, 1975; Foose and 

others, 1980; Singer and DeYoung, 1980) has shown that 

the lognormal distribution closely approximates observed 

distributions of ore tonnage, grade, and contained metal for 

deposits grouped by geologic deposit type. Inclusion of this 

information from deposits not belonging to the specified 

deposit type may result in deviations from lognormal 

distribution. Failure of normality may be identified by using 

standard statistical techniques or may commonly be 

observed on frequency distribution plots as breaks or 

changes in slope. In this study, these techniques were used 

to identify differences in grade, tonnage, or contained barite 

between bedded barite deposits with and without associated 

base-metal sulfide mineralization. 

GEOLOGIC SETTING 

Barite deposits have routinely been classified within 

three major deposit types: veins and cavity fillings, residual 

deposits, and bedded deposits (Brobst, 1984). The bedded 

deposits include all stratiform bodies within layered, generally sedimentary, sequences of rock or the metamorphic 

equivalents that have barite as the principal mineral but are 

not residual deposits or karst fillings. Bedded barite generally occurs in rocks of mid-Paleozoic age, but deposits have 

been reported in rocks as old as Archean and as young as 

Cretaceous (Orris, 1985). The host rock sequences are 

diverse; they most commonly contain chert, argillite, shale, 

and (or) limestone but can also be composed of dolomite, 

slate, tuff and volcaniclastic rocks, sandstone, quartzite, 

greenstone, phyllite, and (or) schist. The host rocks and the 

contained barite are commonly gray to black because of 

included organic material but have been reported in colors 

as diverse as white, cherry red, and green (Orris, 1985). 

Many bedded barite deposits exhibit primary depositional and diagenetic features such as graded bedding or 

crossbedding, rhythmic layering, large-scale interbedding 

of chert or shale and barite, bending of shale layers around 

barite nodules, and stylolite seams at the base of baritic 

layers (Zimmermann and Amstutz, 1964; Zimmermann, 

1969, 1976). Some deposits show replacement features 

including baritized fossils, inclusions of host chert or 

limestone in the barite, and crosscutting of host rock texture 

by blades and rosettes of barite (Ketner, 1965, 1975). 

Evidence of both primary depositional and replacement 

processes is present in many deposits and typically is 

explained by the proposal of a submarine-exhalative genesis 

for the deposit (Zimmermann and Amstutz, 1964; Dawson 

and Orchard, 1982; Papke, 1984). 

Barite-A Comparison for Bedded Barite B1 
In general, the commercial bedded barite deposits are 

composed of fetid, gray to black, fine-grained barite that 

occurs either as massive lenses or in beds that vary from 

thinly laminated to over 15 m thick. Conglomeratic beds, 

barite rosettes or nodules, and barite cement are common in 

some deposits. Most of the ore exceeds 50 percent barite 

and may contain quartz, calcite, organic matter, secondary 

iron oxide, and some clay or mica. Pyrite is the most 

abundant sulfide and occurs in over 50 percent of the 

deposits. Base-metal sulfides are reported in trace to economic quantities in, or closely associated with, over 40 

percent of the deposits (Orris, 1985). 

Bedded barite deposits may occur as essentially 

monomineralic deposits such as those in Nevada (Papke, 

1984). However, in other areas, stratiform barite deposits 

commonly have been reported in association with most 

types of stratiform base-metal deposits including massive 

sulfide mineralization in felsic to intermediate volcanics 

(Singer, 1986) and sediment-hosted exhalative zinc-lead 

deposits (Large, 1981, 1983; Briskey, 1986). Other bedded 

barite deposits are peripheral, or laterally gradational, to 

manganese deposits, bedded iron, phosphate, or evaporitic 

sequences of gypsum and anhydrite. Most of the economic 

bedded barite deposits occur in sequences of rocks similar 

to those of sediment-hosted exhalative zinc-lead deposits, 

but some deposits are in sequences containing abundant 

volcaniclastic rocks and associated with volcanic-hosted 

massive sulfides; other deposits occur in limestone or 

dolomite and are associated with carbonate-hosted deposits. 

GRADE-TONNAGE DATA 

Deposit size and grade data are available for the 30 

bedded barite deposits listed in table 1. Grades are average 

grades for each deposit, and for some deposits the average 

percentage of BaSO 4 was calculated from reported average 

densities of the ore. Sizes of deposits are estimates consisting of reported reserves and any known production. Reserve 

data for these deposits may be calculated on the basis of 

gravity studies, drilling, or geologic inference, but the 

method and level of certainty of the estimation are rarely 

specified. Thirty-two percent of these deposits have associated lead-zinc sulfide mineralization; five of them (Ballynoe, Ireland; Cirque and Mel, Canada; Meggen and 

Rammelsberg, Germany) are considered principally basemetal sulfide deposits. Barite deposits with associated leadzinc sulfides are under-represented in the grade-tonnage 

data set; only 45 percent of the 93 deposits examined 

in this study report the presence of any base-metal 

sulfides. 

The grades collected for most bedded barite deposits 

range from 50 percent to 90 percent barite with a mean of 84 

percent for the compiled grade data. In barite-lead-zinc 

deposits, these grades generally reflect a barite-rich lens or 

82 Contributions to Commodity Geology Research 

zone peripheral to the base-metal sulfide mineralization 

(Brobst, 1984; Briskey, 1986). Lower grades, generally 

less than 30 percent, have been reported for some barite that 

is associated with lead-zinc mineralization; for instance, 

Came (1979) reports 25 percent BaS04 at the Tom leadzinc deposit in the Canadian Yukon, and the Canada 

Department of Energy, Mines and Resources (1980) lists 28 

percent barite in a stratiform body in schist at the Homestake mine in British Columbia. There is a distinct absence 

of reported barite grades between 30 and 50 percent. The 

lower grades of barite may reflect barite present as gangue 

within lead-zinc deposits and recovered only as a byproduct 

or a barite grade determined using total base-metal plus 

barite ore tonnage rather than a barite grade determined 

solely for the barite-enriched portion(s) of the deposit. 

The sample population of 30 barite grades does not 

have a normal distribution; this is shown by an equivalent of 

the Shapiro-Wilks test of normality (Shapiro, 1980; Ryan 

and others, 1982 ). The correlation factors produced by this 

test and other summary statistics are presented in table 2. 

The lack of normality is visually apparent in the convex 

shape of the inverse cumulative frequency distribution plot 

of grades (fig. 1). The grade distribution of bedded barite 

can be attributed to what might be termed the mineralogical 

limit of barite; it is not possible to have greater than 100 

percent barite ore to round out the distribution. 

Grade populations of bedded barite deposits with and 

without associated base-metal sulfides were plotted and 

compared to determine if there were significant differences 

in grade between the two sample populations. (Summary 

statistics are available in table 2.) The distribution of the 

subset of deposits with base-metal sulfides cannot be shown 

to be different from a normal distribution, probably because 

of the small sample size (n=9), and a Mann-Whitney 

comparison (Ryan and others, 1982) of the medians of the 

subsets does not show them to be significantly different at 

the 5-percent level. Therefore, bedded barite with associated base-metal sulfides cannot be shown to be different 

from bedded barite without associated base-metals on the 

basis of grade. Because the shapes of the grade curves for 

the subsets are similar, the frequency distribution is considered appropriate for estimating the occurrence of undiscovered deposit grades even though the population is not 

normal. 

Unlike grade, tonnage shows a lognormal frequency 

distribution for bedded barite deposits (fig. 2, table 2). 

Again, a Mann-Whitney comparison of the medians of the 

two sample populations composed of barite with and 

without associated base-metals fails to show that the tonnage sample populations are different. Ore tonnages for the 

30 bedded barite deposits range from approximately 40,000 

metric tons to over 55,000,000 metric tons with a median of 

2,600,000 metric tons (fig. 3). Correlation of tonnage with 

grade is not significantly different than zero; grade neither 

increases nor decreases in a predictable way with tonnage. 
Table 1. Bedded barite deposits used for grade and tonnage models 

Name Location 

Ballynoe ..................... . Ireland ...................... . 

Ban Thimontha ............... . Thailand ..................... . 

Barite (Moose) ............... . Yukon Territory, Canada ...... . 

Barite Valley ................. . South Africa ................. . 

Baw Hin Khao ............... . Thailand ..................... . 

Brookfield .................. . Nova Scotia, Canada ......... . 

Camamu Bay ................ . Brazil ....................... . 

Castle Island ................. . Alaska, United States ......... . 

Cathy (Walt) ................. . Yukon Territory, Canada ...... . 

Cirque ....................... . British Columbia, Canada ..... . 

Foss-Ben Eagach ............ . Great Britain ................. . 

Greystone .................... . Nevada, United States ........ . 

Gurrunda .................... . New South Wales, Australia .. . 

Kempfield ................... . New South Wales, Australia .. . 

Khuzdar ..................... . Pakistan ..................... . 

Magnet Cove ................ . Arkansas, United States ....... . 

Mangampeta (2 deposits) ...... . India ........................ . 

Meggen ..................... . Germany .................... . 

Mel ........................ . Yukon Territory, Canada ...... . 

Mountain Springs ............ . Nevada, United States ........ . 

Nimiuktuk ................... . Alaska, United States ........ . 

Phu Mai Tong ............... . Thailand ..................... . 

Rammelsberg ................ . Germany .................... . 

Savercool .................... . California, United States ...... . 

Schoonoord .................. . South Africa ................. . 

Snake Mountains ............. . Nevada, United States ........ . 

Tea ......................... . Yukon Territory, Canada ..... . 

Uribe ........................ . Washington, United States ..... 

Weekaroo .................... . South Australia, Australia ..... . 

A Shapiro-Wilks equivalent test of normality (table 2) 

shows that contained barite tonnages have normal distri~ution for the base-metal-sulfide and no base-metal-sulfide 

subsets, as well as for the data set as a whole. Contained 

barite is the total amount of barite contained within a 

deposit, approximated by the product of the deposit tonnage 

and average grade. As with grade and ore tonnage, a 

Mann-Whitney comparison failed to show that the subsets 

were significantly different from each other. Contained 

barite has a high (r=0.99) positive correlation with ore 

tonnage, but its correlation with grade is not significantly 

different from zero. The strong correlation between contained metal and deposit tonnage was observed by Singer 

and DeYoung (1980) to be typical for the deposit types they 

investigated, as was the lack of correlation between conAge, host rocks 

Carboniferous carbonaceous shale, dolostone, and minor chert 

and limestone. 

Ordovician-Silurian shale and sandstone. 

Devonian-Mississippian black carbonaceous argillite, black 

chert, and conglomerate. 

Archean chert, shale, and tuffites. 

Devonian-Mississippian dolomite and minor shale. 

Mississippian ferruginous shale and siltstone. 

Cretaceous arkosic sandstone and shale with conglomerate and 

limestone. 

Siliceous metasedimentary rock, pillow lavas. 

Devonian argillite, shale, limestone, chert, and conglomerate. 

Devonian black carbonaceous shale, siliceous argillite, and 

chert. 

Proterozoic schist. 

Devonian black chert with minor black argillite, gray shale, 

and limestone(?). 

Silurian tuffaceous sandstone, shale, and volcanic rocks. 

Silurian siltstone, shale, and volcanic rocks. 

Jurassic gray limestone and shale. 

Mississippian shale, sandstone. 

Cambrian(?) carbonaceous shale, dolostone, and quartzite. 

Middle Devonian slate, limestone, and shale. 

Cambrian-Ordovician limey shale, limestone, and phyllite. 

Devonian black chert with minor argillite and shale. 

Upper Mississippian black carbonaceous shale and chert. 

Ordovician-Devonian(?) shale. 

Devonian carbonaceous black shale and slate with sandstone, 

limestone, and tuff. 

Carboniferous limestone, slate, and quartzite. 

Chert. 

Ordovician chert, shale, argillite, conglomerate, limestone, 

greenstone, and siltstone. 

Lower Mississippian black argillite, shale, siltstone, chert, and 

limestone. 

Paleozoic siliceous siltstone and argillite with intercalated 

limestone. 

Archean. 

tained metal and grade. The strong correlation between 

contained metal and deposit tonnage suggests the observed 

lack of correlation between grade and tonnage. 

SUMMARY 

The grade, tonnage, and contained barite content of 

bedded barite deposits show that stratiform deposits with 

and without base-metal sulfides may be treated statistically 

as a single deposit type when estimating barite resources. 

The independence of grade and tonnage for bedded barite 

deposits is convenient for modeling grades and tonnages of 

undiscovered deposits in the manner described by Singer 

and others (1975) for porphyry copper deposits. 

Barite-A Comparison for Bedded Barite B3 
Table 2. Summary statistics for bedded barite grade, tonnage, and contained barite 

[All statistics generated by using MINITAB (Ryan and others, 1982) on an IBM personal computer; n, number; t, metric ton] 

Median 

Standard Shapiro-Wilks n Mean Comment 

deviation correlation 

Grades 

All deposits ............................... 30 84.6% 90.0% 0.123 0.923 not lognormal 

Barite ± pyrite ............................ 21 87.1% 90.3% .098 .928 not lognormal 

Barite ± base-metal sulfides ............... 9 78.6% 85.0% .159 .938 normal 

Tonnages 

All deposits ............................... 30 1,663,000 t 2,606,000 t .903 .984 lognormal 

Barite ± pyrite ............................ 21 1,641,000 t 2,723,000 t .901 .981 lognormal 

Barite ± base-metal sulfides ............... 9 1,714,000 t 2,500,000 t .961 .974 lognormal 

Contained barite 

All deposits ............................... 30 1,390,000 t 2,307,000 t .901 .981 lognormal 

Barite ± pyrite ............................ 21 1,419,000 t 2,323,000 t .912 .980 lognormal 

Barite ± base-metal sulfides ............... 9 1,321,000 t 2,123,000 t .930 .963 lognormal 

1.0 1.0 

0 

0.9 0.9 

0.8 0.8 

en (/) 1- 1- 0.7 (jj 0.7 U5 0 0 a.. a.. UJ 0.6 UJ Q 0.6 Q u. u. 0 0.5 0 0.5 

z z 0 0 i= 0.4 i= 0.4 

a: a: 0 0 a.. a.. 0.3 

0 0.3 0 

a: a: 

a.. a.. 0.2 

0.2 

0.1 0.1 

0.0 

0.0 0 20 30 40 50 60 70 80 90 100 0.0004 0.0063 0.1 1.6 25 400 

BARITE GRADE (IN PERCENT) 

Figure 1. Inverse cumulative frequency plot of grades for 

30 bedded barite deposits. 

84 Contributions to Commodity Geology Research 

MILLION METRIC TONS 

Figure 2. Inverse cumulative frequency plot of deposit 

tonnage for 30 bedded barite deposits. 
1.0 

0.9 

0.8 

(/) 

1- 0.7 U5 

0 

a. 

w 0.6 

0 

u.. 

0 0.5 

z 

0 

i= 0.4 

a: 

0 

a. 0.3 0 

a: 

a. 0.2 

0.1 

0.0 

0.0004 0.0063 0.1 1.6 25 400 

MILLION METRIC TONS 

Figure 3. Inverse cumulative frequency plot of contained 

barite for 30 bedded barite deposits. 

REFERENCES CITED 

Briskey, J .A., 1986, Descriptive model of sedimentary exhalative 

Zn-Pb, in Cox, D.P., and Singer, D.A., eds., Mineral 

deposit models: U.S. Geological Survey Bulletin 1693, p. 

211-212. 

Brobst, D.A., 1984, The geological framework of barite 

resources: Institution of Mining and Metallurgy Transactions, 

sec. A, v. 93, p. A123-Al30. 

Canada Department of Energy, Mines and Resources, 1980, 

Canadian mineral deposits not being mined in 1980: Mineral 

Policy Sector Internal Report MRI 8017, 294 p. 

Carne, R.C., 1979, Geological setting and stratiform 

mineralization Tom claims, Yukon Territory: Canada 

Department of Indian Affairs Northern Development OpenFile Report EGS-1979-4, 30 p. 

Dawson, K.M., and Orchard, M.J., 1982, Regional metallogeny 

of the northern cordillera: biostratigraphy, correlation and 

metallogenic significance of bedded barite occurrences in 

eastern Yukon and western District of Mackenzie: Canada 

Geological Survey Paper 82-lC, p. 31-36. 

Foose, M.P., Menzie, W.D., Singer, D.A., and Hanley, J.T., 

1980, The distributions and relationships of grade and 

tonnage among some nickel deposits: U.S. Geological 

Survey Professional Paper 1160, 14 p. 

Ketner, K.B., 1965, Economic geology, in Gilluly, James, and 

Gates, Olcott, eds., Tectonic and igneous geology of the 

northern Shoshone Range, Nevada: U.S. Geological Survey 

Professional Paper 475-B, p. B38-B41. 

---1975, Replacement barite deposit, southern Independence 

Mountains, Nevada: U.S. Geological Survey Journal of 

Research, v. 3, no. 5, p. 547-551. 

Krebs, Wolfgang, 1981, The geology of the Meggen ore deposit, 

in Wolf, K.H., ed., Handbook of strata-bound and stratiform 

ore deposits: New York, Elsevier, v. 9, p. 509-549. 

Large, D .E., 1981, Sediment-hosted submarine exhalative leadzinc deposits-A review of their geological characteristics 

and genesis, in Wolf, K.H., ed., Handbook of strata-bound 

and stratiform ore deposits: New York, Elsevier, v. 9, p. 

469-508. 

---1983, Sediment-hosted massive sulfide lead-zinc deposits: 

An empirical model, in Sangster, D.F., ed., Sediment-hosted 

stratiform lead-zinc deposits: Mineralogical Association of 

Canada Short Course Handbook, v. 8, p. 1-30. 

Orris, G.J., 1985, Bedded/stratiform barite deposits-Geologic 

and grade-tonnage data including a partial bibliography: U.S. 

Geological Survey Open-File Report 85-447, 32 p. 

Papke, K.G., 1984, Barite in Nevada: Nevada Bureau of Mines 

and Geology Bulletin 98, 125 p. 

Ryan, T.A., Jr., Joiner, B.L., and Ryan, B.F., 1982, MINITAB 

reference manual: Pennsylvania State University, Statistics 

Department, 156 p. 

Shapiro, S. S. , 1980, How to test normality and other 

distributional assumptions: Milwaukee, Wisconsin, 

American Society for Quality Control, 78 p. 

Singer, D.A., 1986, Descriptive model of Kuroko massive 

sulfide, in Cox, D.P., and Singer, D.A., eds., Mineral 

deposit models: U.S. Geological Survey Bulletin 1693, p. 

189-190. 

Singer, D.A., Cox, D.P., and Drew, L.J., 1975, Grade and 

tonnage relationships among copper deposits: U.S. 

Geological Survey Professional Paper 907-A, 11 p. 

Singer, D.A., and DeYoung, J.H., Jr., 1980, What can gradetonnage relations really tell us?, in Guillemin, Claude, and 

Lagny, Phillipe, eds., Res sources minerales-Mineral 

resources: [France] Bureau of Recherches Geologiques et 

Minieres Memoir 106, p. 91-101. 

Taylor, S., and Andrew, C.J., 1978, Silvermines orebodies, 

County Tipperary, Ireland: Institution of Mining and 

Metallurgy Transactions, sec. B, v. 87, p. B111-B124. 

Zimmermann, R.A., 1969, Strata-bound barite deposits in 

Nevada: Mineralium Deposita, v. 4, p. 401-409. 

---1976, Rhythmicity of barite-shale and of Sr in strata-bound 

deposits in Arkansas, in Wolf, K.H., ed., Handbook of 

strata-bound and stratiform ore deposits: New York, Elsevier, 

v. 1, p. 339-353. 

Zimmermann, R.A., and Amstutz, G.C., 1964, Small scale 

sedimentary features in the Arkansas barite district, in 

Amstutz, G.C., ed., Sedimentology and ore genesis; 

proceedings of a symposium held during the Sixth 

International Sedimentological Congress, 6th, Delft-1963: 

New York, Elsevier, p. 157-163. 

Barite-A Comparison for Bedded Barite B5 

Chapter C 

Gold-Distribution of Gold in Porphyry 

Copper Deposits 

By DENNIS P. COX and DONALD A. SINGER 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract Cl 

Introduction Cl 

Factors Related to Gold Content of Porphyry Copper Deposits C2 

Copper-Molybdenum Content C2 

Magnetite Content C2 

Deposit Morphology C4 

Depth of Emplacement CS 

Deposit Tonnage CS 

Associated Igneous Rocks C6 

Characteristics of Porphyry Copper-Gold Deposits C6 

Characteristics of Porphyry Copper-Gold-Molybdenum Deposits C6 

Characteristics of Porphyry Copper-Molybdenum Deposits C7 

Geochemical Interpretation C8 

References Cited C 13 

FIGURES 

1-3. Triangular plots showing: 

1. Fifty-five porphyry copper deposits plotted according to their copper, gold, 

and molybdenum content C3 

2. Silver grade of porphyry copper deposits C4 

3. Magnetite content of porphyry copper deposits CS 

4. Graph of magnetite content vs. gold grade for 26 porphyry copper 

deposits C6 

5, 6. Triangular plots showing: 

5. Porphyry copper deposits according to their morphologic class C7 

6. Depth of emplacement of porphyry copper deposits C8 

7. Graph of estimated depth of emplacement vs. gold grade for 18 porphyry 

copper deposits C9 

8, 9. Triangular plots showing: 

8. Tonnage classes of porphyry copper deposits ClO 

9. Type of ore-related intrusive rock in porphyry copper deposits Cll 

10-12. Cross sections of typical: 

10. Porphyry copper-gold deposit C12 

11. Porphyry copper-gold-molybdenum deposit C12 

12. Porphyry copper-molybdenum deposit C13 

TABLES 

1. Porphyry copper deposits examined in this study and classified by their gold and 

molybdenum content Cl 

2. Median grades, tonnages, and depths by type of porphyry copper 

deposit C6 

Contents Ill 

Gold- Distribution of Gold in Porphyry Copper 

Deposits 

By Dennis P. Cox and Donald A. Singer 

Abstract 

Analysis of 55 porphyry copper deposits demonstrates a continuum between porphyry copper-gold 

deposits emplaced at a median depth of 1 km, with a 

median size of 160 million metric tons of copper ore and a 

median content of 2.6 percent magnetite in the potassic 

alteration zone, and porphyry copper-molybdenum 

deposits emplaced at a median depth of 3.6 km, with a 

median size of 500 million metric tons and little magnetite. 

Molybdenum commonly occurs in low-grade peripheral 

zones outside the copper orebody in the porphyry 

copper-gold-type deposits. Gold grades are less than 0.05 

ppm in the porphyry copper-molybdenum deposits. 

Between these end members is an economically important 

group containing significant amounts of both gold and 

molybdenum. 

INTRODUCTION 

This paper expands and refines ideas about the 

distribution of gold in porphyry copper deposits. Previous 

contributors in this area are Kesler (1973) who plotted gold, 

molybdenum, and copper content of porphyry ores on a 

triangular coordinate system and related gold and molybdenum content to tectonic environment; Sillitoe (1979, 1982) 

who noted the correlation between gold grade and magnetite 

content in the potassic alteration zones of porphyry copper 

deposits; and Sinclair and others (1982) who noted other 

factors, such as deposit morphology, that are correlated 

with gold content. 

In this paper we review information on gold distribution within certain individual well-studied deposits and 

compare these data to information on a group of 55 deposits 

for which we have data on tonnage and on grade of copper, 

gold, and molybdenum (table 1). These data came partly 

from files of the U.S. Bureau of Mines (R. Rosencranz, 

written commun., 1983) and partly from other proprietary 

sources. Estimated premining tonnages, average grades, 

and the lowest available cutoff grades of well-explored 

deposits were used. Because of the proprietary nature of 

some of these data, it is not possible for us to present them 

in a way that permits identification of individual deposit 

grades. 

Table 1. Porphyry copper deposits examined in this study 

and classified by their gold and molybdenum content 

Porphyry copper deposit type 

Porphyry copper- Porphyry copper- Porphyry coppergold gold-molybdenum molybdenum 

Afton, British Columbia Ajo, Arizona Berg, British Columbia 

Basay, Philippines Andacolla, Chile Bethlehem, British 

Bell, British Columbia Bingham, Utah Columbia 

Caribou Bell, British Brenmac-Sultan, Brenda, British 

Columbia Washington Columbia 

Copper Mountain, Cash, Yukon Territory Gambier Island, British 

British Columbia Casino, Yukon Territory Columbia 

Dos Pobres, Arizona Cerro Colorado, Panama Gibraltar, British 

Fish Lake, British Copper Flat, New Columbia 

Columbia Mexico Highmont, British 

Frieda River, Papua Dexing, China Columbia 

New Guinea Granisle, British Huckleberry, British 

Galore Creek, British Columbia Columbia 

Columbia Island Copper, British Inspiration, Arizona 

Ingerbelle, British Columbia Lomex, British 

Columbia Kalamazoo, Arizona Columbia 

Mamut, Malaysia Morrison, British Morenci, Arizona 

Marcopper, Philippines Columbia Ray, Arizona 

Ok Tedi, Papua New Poison Mountain, Sierrita-Esperanza, 

Guinea British Columbia Arizona 

Panguna, Papua New Ruth, Nevada Tyrone-; New Mexico 

Guinea Shaft Creek, British Twin Buttes, Arizona 

Red Chris, British Columbia Valley Copper, British 

Columbia Sipalay, Philippines Columbia 

Rio Vivi, Puerto Rico Yandera, Papua New 

Saindak South, Pakistan Guinea 

Star Mountain, Papua Santa Rita, Arizona 

New Guinea 

Tanama, Puerto'Rico 

Taysan, Philippines 

The deposits include 20 examples here classified as 

porphyry copper-gold deposits (PCD-Au) (typified by the 

Dos Pobres deposit in Arizona), 19 classified as porphyry 

copper-gold-molydenum deposits (PCD-Au-Mo) (of which 

Bingham, Utah, is a good example), and 16 classified as 

porphyry copper-molybdenum deposits (PCD-Mo)(typified 

Gold- Distribution of Gold in Porphyry Copper Deposits C1 
by Sierrita-Esperanza, Ariz.). The classification (following 

Kesler, 1973) is based on distribution of the deposits on a 

triangular coordinate plot showing their copper grade in 

percent, molybdenum content in percent times 10, and gold 

grade in parts per million (ppm) (fig. 1). Our conclusions 

are that the three types differ significantly in metal content, 

magnetite content, deposit morphology, depth of emplacement, and tonnage. 

FACTORS RELATED TO GOLD CONTENT OF 

PORPHYRY COPPER DEPOSITS 

Copper-Molybdenum Content 

In this paper we define the porphyry copper-gold 

model as having high gold and low molybdenum grade in a 

magnetite-rich potassic alteration zone of a porphyry copper 

deposit. Excluded are gold-rich copper skarn orebodies and 

porphyry systems where gold mineralization was clearly 

epithermal, younger, or distally related to the intrusion. 

Because of the gradational variation of gold content and its 

interdependence with molybdenum, it is not possible to 

define PCD-Au systems on the basis of gold content alone. 

Most of the deposits contain 0.3 to 0. 7 ppm gold, but some 

deposits containing less than 0. 2 ppm fit the model in other 

ways such as mineralogy and alteration zoning. The PCDAu model can be defined more precisely in terms of gold 

and molybdenum grades according to the relation: 

Au 

Mo ~ 30 (1) 

where gold is in parts per million and molybdenum is in 

percent. Equation 1 is plotted on the triangular coordinate 

plot in figure 1 and separates a group of 20 deposits on the 

right-hand side that are all good examples of the PCD-Au 

model. 

Gold occurs in porphyry copper deposits in various 

forms: micron-size particles of free gold were described at 

Ingerbelle, B.C. (J. McCue, Newmont Mines Ltd., unpublished report, 1980); free gold is associated mainly with 

bornite, partly with chalcopyrite, and negligibly with pyrite 

at Panguna, Papua New Guinea (Baldwin and others, 

197 8); small grains of electrum containing 11. 5 to 18. 5 

percent silver are associated with bornite-gangue grain 

boundaries at Granisle, B.C., and with chalcopyrite and 

pyrite at Bell, B.C. (Carson and others, 1970; Cuddy and 

Kesler, 1982); and inclusions of sylvanite and hessite occur 

in bornite at Dos Pobres, Ariz. (Langton and Williams, 

1982). 

Gold content is positively correlated with copper 

grade within some deposits such as Ingerbelle, B.C. (J. 

McCue, Newmont Mines Ltd., unpublished report, 1980), 

and Sapo Alegre, Puerto Rico (Cox and others, 1975). 

Cuddy and Kesler (1982) found a high correlation of gold 

C2 Contributions to Commodity Geology Research 

grade with bornite content at Granisle, B.C. In some 

deposits, such as Tanama, Puerto Rico (Cox, 1986), gold 

and copper grades are independent. For the 55 deposits used 

in this study, gold and copper average grades are independent at the 1-percent level of significance. Median copper 

grade for the data set is 0.48 percent. 

Within many porphyry deposits, gold grade is negatively correlated with molybdenum grade as pointed out by 

Popov (1977) and Sillitoe (1982). The low molybdenum 

content of porphyry copper-gold deposits is related to the 

fact that in many systems molybdenum is distributed as a 

peripheral zone outside the copper-gold orebody that itself 

has a low molybdenum grade. At Dos Pobres (Langton and 

Williams, 1982), 0.005 to 0.015 percent molybdenum 

occurs in a quartz-sericite-pyrite alteration zone lying partly 

within the outer fringe of the> 0.5-percent-copper orebody 

and partly outside of the ore body. A similar relation is cited 

by Sillitoe ( 1979) at Saindak, Pakistan; Bajo de Alumbrera, 

Argentina; and Dizon, Philippines. 

This antipathetic relationship of gold and molybdenum, although not so well developed in other PCD-Au 

deposits, gives rise to an overall negative correlation of the 

two metals when data from all 55 deposits in the population 

are studied. The correlation coefficient between gold and 

molybdenum is low (r= -0.45) but is significant at the 

1-percent level. 

Of the 48 deposits for which a silver grade also was 

available, no correlation was found between silver content 

and that of gold, molybdenum, or copper (fig. 2). Median 

silver grade for the data set is 1.5 ppm. 

Magnetite Content 

Magnetite in veinlets makes up more than 1 percent 

by volume of most porphyry copper-gold orebodies (Saegart and Lewis, 1977; Sillitoe, 1979). Magnetite forms 

stable assemblages with any of the minerals that characterize potassic or feldspar-stable alteration: chalcopyrite, 

biotite, anhydrite, K-feldspar, chlorite, or actinolite. 

Excluded from this general rule are magnetite-rich skarn 

orebodies and relict magnetite in replacement orebodies in 

mafic igneous rocks such as those found at Ray, Ariz. The 

converse of this rule-that magnetite in porphyry copper 

orebodies is positively correlated with gold content-has 

numerous exceptions. Magnetite is mentioned as a rare 

mineral at Poston Butte (Nason and others, 1982) and 

Sacaton (Cummings, 1982), Ariz. No gold grade is reported 

for these deposits. At Bethlehem, B.C., secondary magnetite appears as clusters with K-feldspar in the potassic 

alteration zone without attendant gold mineralization (J.A. 

Briskey, oral commun., 1984). At Mineral Park, Ariz. 

(Wilkinson and others, 1982), a late magnetitechalcopyrite-chlorite vein system cuts early quartzK-feldspar-biotite-molybdenite veins. These veins form a 
PCD-Mo PCD-Au-Mo PCD-Au 

Mox10 

Figure 1. Fifty-five porphyry copper deposits plotted 

according to their copper, gold, and molybdenum content 

following Kesler (1973). Diamond symbols represent 

individual deposits. Contour lines represent gold content 

low-grade copper zone (average 0.069 percent Cu) roughly 

coextensive with the molybdenum orebody containing 

>0.03 percent molybdenum. According to Luis Vega 

(written commun., 1984), the Mineral Park porphyry system contains essentially no gold. Magnetite-chlorite veins 

are also associated with molybdenum mineralization in the 

Malala district of Sulawesi (Taylor and Van Leeuwen, 

1980). Magnetite and molybdenite form fracture fillings in 

quartz porphyry. The Malala deposit contains 0. 24 percent 

MoS2 and subordinate amounts of copper. 

Despite these exceptions, magnetite content is positively correlated with gold grade in the deposits included in 

this study. Where magnetite content is not given in percent 

Au ppm 

of deposits in grams per metric ton. PCD-Mo=Porphyry 

copper-molybdenum; PCD-Au-Mo =Porphyry coppergold-molybdenum; and PCD-Au =Porphyry copper-gold. 

in deposit descriptions, word descriptors were converted to 

numerical estimates according to the following scheme: 

trace, rare 0.05 

present 1 

abundant 3 

Magnetite content is plotted on the triangular diagram 

in figure 3 and versus gold in figure 4. The correlation 

coefficient (r=0.68) is significant at the 1-percent level for 

26 deposits for which an estimated magnetite content 

greater than zero was known (fig. 4). The deposit represented by the point having high gold and low magnetite 

content (upper left side of the field) had an original high 

Gold- Distribution of Gold in Porphyry Copper Deposits C3 
Cu 

Mo x10 Au ppm 

Figure 2. Silver grade of porphyry copper deposits in ppm. Positions of data points represent their copper, gold, and 

molybdenum content as shown in figure 1. No systematic variation is observed. 

content of magnetite that was largely replaced by pyrite 

during late-stage phyllic alteration. 

Deposit Morphology 

Sinclair and others (1982) applied the porphyry classification scheme of Sutherland Brown (1976) to a group of 

porphyry deposits in British Columbia and found that 

porphyry copper-gold deposits tend to be in classic- and 

volcanic-type intrusive systems. According to Sutherland 

Brown, classic-type deposits are centered around small 

cylindrical plutons. They are commonly associated with 

breccia pipes and have concentric zones of alteration and 

C4 Contributions to Commodity Geology Research 

mineralization. Coeval volcanic rocks are commonly absent 

in these deposits. Volcanic-type deposits are related to 

irregular or dikelike igneous bodies that have intruded "a 

coeval and at least partly, consanguineous volcanic pile" 

(Sutherland Brown, 1976, p. 46). We have plotted on figure 

5 all deposits of volcanic type plus all those known to have 

coeval volcanic rocks exposed at or within a kilometer of 

the deposit. These deposits show a strong concentration on 

the PCD-Au side of the diagram. In contrast, plutonic-type 

porphyry deposits, characterized by mineralization in integral zones of medium-sized plutons having phanerocrystalline textures (Sutherland Brown, 1976, p. 48-49), are 

concentrated on the high-molybdenum, low-gold side of the 

diagram. 
Cu 

Mo x10 Au ppm 

Figure 3. Magnetite content in volume percent in potassic alteration zones in porphyry copper deposits. Position of data 

points as in figure 1. 

Depth of Emplacement 

Estimates of depth of emplacement, shown in figure 

6, were taken from geologic reports on individual deposits 

and from Sutherland Brown (1976, fig. 1). The estimates 

show a negative correlation with gold grade of -0.90, 

which is significant at the 1-percent level for 18 deposits 

(fig. 7). Given the close relation between gold content and 

deposit classification, this correlation is expected because 

volcanic-type deposits tend to be emplaced at shallow levels 

in the crust and because the deep erosion required to expose 

plutonic-type deposits emplaced at deep levels in the crust 

commonly removes all traces of supracrustal volcanic 

rocks. 

Deposit Tonnage 

Sillitoe (1979) noted no relation between deposit 

tonnage and gold grade in his set of 16 deposits having gold 

grade greater than or equal to 0.4 ppm. For our set of 55 

deposits, which includes a wider range of gold grades, 

however, there is a low correlation of -0.42 between 

deposit tonnage and gold grade; this correlation is significant at the 1-percent level. Median tonnage of the PCD-Mo 

type is roughly three times that of PCD-Au type (table 2), 

and the tonnages are significantly different. Tonnage 

classes plotted on figure 8 show a preponderance of small 

deposits on the high-gold side and a concentration of large 

deposits on the high-molybdenum side. This correlation is 

Gold- Distribution of Gold in Porphyry Copper Deposits C5 
1.0 

z 

~ () 

a: 0.32 

1-

w 

~ 

(fj 

~ 0.1 

<( 

a: 

~ 

z 

0.032 w~ 

Cl 

<( 

a: 

~ 

Cl 

....I 

0 

~ 

0.01 

0.0032 .__ __ ....._ __ __._ ___ ....__ __ ......... __ __. 

0.05 0.13 0.32 0.79 2.0 5.0 

MAGNETITE CONTENT, IN PERCENT 

Figure 4. Magnetite content vs. gold grade for 26 porphyry 

copper deposits. Correlation is 0.68, which is significant at 

the 1-percent level. 

probably closely related to an inherent difference in tonnage 

between volcanic and plutonic types of deposits. 

Associated Igneous Rocks 

Descriptions of rock types believed to be genetically 

related to porphyry copper deposits were taken from the 

literature and converted into standard rock terminology 

(Streckeisen, 1973). These types are plotted on figure 9. Of 

the 20 PCD-Au systems, 8 occur with tonalite or quartz 

diorite, 6 with syenite or monzonite, and 6 with granodiorite or monzogranite. Of the 16 PCD-Mo systems, 12 

occur with monzogranite and granodiorite, 3 with tonalite, 

and 1 is undetermined. Of 19 deposits classified as PCDAu-Mo type, 13 were associated with monzogranite and 

granodiorite, 4 with tonalite, and 2 were undetermined. 

We agree with Sillitoe (1979) that associated rock 

type is not a good descriptor of porphyry copper-gold 

deposits. There is possibly a general tendency, not shown in 

the above data, for PCD-Au systems to be associated with 

the rocks rich in mafic minerals and for PCD-Mo and 

PCD-Au-Mo systems to occur with monzogranite and 

granodiorite having low mafic-mineral content. 

CHARACTERISTICS OF PORPHYRY 

COPPER-GOLD DEPOSITS 

Porphyry copper-gold deposits have Au:Mo 

satisfying equation 1 and median gold grades of 0.38 g/t 

C6 Contributions to Commodity Geology Research 

Table 2. Median grades, tonnages, and depths by type of 

porphyry copper deposit 

Porphyry Porphyry Porphyry coppercopper- gold- copper 

gold type molybde- molybdenum type num type 

Number of deposits ......... 20 19 16 

Metric tons x 106 ........... 160 390 500 

Copper (percent) • 0 ••••••••• .55 .48 .41 

Molybdenum (percent) ...... .003 .015 .016 

Gold (g/t) ................. .38 .15 .012 

Silver (g/t) ................ 1.69 1.63 1.22 

Magnetite content (percent) .. 2.6 1.0 .05 

Depth (km) ............... 1.0 .9 3.6 

(table 2). The richest deposits contain 0.9 g/t (Sillitoe, 

1979). Median molybdenum grades are 0.003 percent 

within copper-gold orebodies, but peripheral zones reaching 

0.01 percent molybdenum may occur outside the coppergold orebody. Median deposit tonnage is 160 million metric 

tons. The largest deposit, Panguna, Papua New Guinea, 

exceeds 1 billion metric tons. 

Porphyry copper-gold deposits tend to form in and 

around dike swarms or cylindrical plutons of tonalite or 

syenite-monzonite intruding coeval volcanic rocks (fig. 10). 

The ore-related intrusions may also be of granodiorite and 

monzogranite composition. In deposits for which depths of 

emplacement have been estimated, the median depth is 

about 1 km. All deposits that have not been affected by 

pervasive late-stage phyllic alteration and pyritization have 

magnetite as a stable member of the potassic alteration 

assemblage. The median magnetite content is 2.6 percent. 

CHARACTERISTICS OF PORPHYRY 

COPPER-GOLD-MOLYBDENUM DEPOSITS 

Deposits of the PCD-Au-Mo type have gold and 

molybdenum contents that satisfy the relation: 

Au 

3>Mo <30, (2) 

where molybdenum and gold are each measured as in 

equation 1. Median gold grade for this deposit type is 0.15 

g/t, and median molybdenum content is 0.015 percent Mo. 

Median tonnage is 390 million metric tons (table 2). This 

deposit type includes some large-tonnage deposits that, with 

their correspondingly high production rates, are important 

gold producers. Bingham, the largest deposit in this type 

class, was for many years the second-ranking gold producer 

in the United States. 
Cu 

.c •V 

.c •V 

·C 

.P 

v 

Mo x10 Au ppm 

Figure 5. Porphyry copper deposits according to their morphologic class following Sutherland Brown (1976). V's 

represent volcanic-type plus some classic-type deposits in which coeval volcanic rocks are abundant near the deposit. C 

is classic type and P is plutonic type. 

Both classic- and volcanic-types of deposits contain 

gold together with molybdenum in copper orebodies. In the 

classic type, gold is contained in both the intrusive porphyry 

and in related gold-rich skarn deposits such as at Bingham, 

Utah; Ruth, Nev.; and Santa Rita, N.M. (fig. 11). Most 

deposits are related to intrusions of monzogranite and 

granodiorite composition. Magnetite is commonly present 

in the potassic alteration assemblage, and the median 

magnetite content for nine of these deposits is 1 percent. 

PCD-Au-Mo systems may have important additional gold 

mineralization in peripheral vein or replacement-type 

deposits (fig. 11). 

CHARACTERISTICS OF PORPHYRY 

COPPER-MOLYBDENUM DEPOSITS 

Deposits of the PCD-Mo system have gold and 

molybdenum content defined by the relation: 

Au 

Mo- ->3 (3) 

where molybdenum and gold are measured as in equation 1. 

Median molybdenum grade for this type of deposits is not 

significantly different from that of the PCD-Au-Mo deposit 

Gold- Distribution of Gold in Porphyry Copper Deposits C7 
Cu 

Mo x10 Au ppm 

Figure 6. Porphyry copper deposits according to their estimated depth of emplacement in kilometers. 

type. Median gold values are 0.012 g/t. Median deposit 

tonnage is 500 million metric tons. 

Classic-type porphyry copper deposits dominate the 

PCD-Mo deposit type in the United States, and plutonictype porphyry deposits are important in British Columbia. 

Figure 12 is a diagram showing characteristics of the latter 

type. Median depth of emplacement is 3.6 km (table 2). 

Intrusions associated with ore deposition are mainly monzogranite in the United States and granodiorite or tonalite in 

British Columbia. Median magnetite content of potassic 

alteration zones is 0. 05 percent. Some deposits have 

important gold-bearing vein, carbonate replacement, or 

skarn deposits arranged peripherally around the porphyry 

intrusion. 

C8 Contributions to Commodity Geology Research 

GEOCHEMICAL INTERPRETATION 

Data presented by Chaffee (1982) for San Manuel, 

Ariz., show that gold is concentrated in two environments, 

one within the porphyry copper orebody and the other about 

1 ,200 m outward from the orebody in the propylitic 

alteration zone. This arrangement implies that two 

transport-deposition processes may be necessary to explain 

gold distribution in porphyry systems. One possible 

suggestion is that gold is deposited from gold complexes at 

high temperature in the interior of the system and that this 

gold is partly remobilized at lower temperature and 

relatively higher f8 conditions as thiocomplex ions and is 

transported to peripheral parts of the system. As Sillitoe 
1.0 

z 

~ () 

a: 0.32 

1--

w 

~ 

(7j 

~ 0.1 

<( 

a: 

<.9 

z 

wo 

<( 

a: 

<.9 

0 

.....J 

0 

<.9 

0.032 

0.01 

0.89 1.4 2.2 3.5 5.6 

DEPTH, IN KILOMETERS 

Figure 7. Estimated depth of emplacement vs. gold grade 

for 18 porphyry copper deposits. The correlation is -0.90, 

which is significant at the 1-percent level. 

(1982) has pointed out, high f 0 /fs 1

, as evidenced by high 

magnetite-to-pyrite ratios in PCD-Au systems, seem, in 

most cases, to be responsible for trapping gold in the 

copper-rich part of the system. Where the magnetite-pyrite 

ratio is low in the potassic alteration stage, sufficient sulfide 

ions may have been present to cause gold to remain mobile 

as gold thiocomplex ions during falling temperatures (Henley, 1973). In such chemical environments, gold would 

migrate outward to form peripheral gold vein-type deposits. 

One possible mechanism for maintaining highf0 lfs during 

the early gold-deposition stage might be the diss~ci~tion of 

H20 to H2 and 0 2. This reaction would be favored by the 

high temperatures and low pressures that would be 

associated with tonalite and other more mafic intrusions 

emplaced at high levels in the crust. Escape of the smaller 

hydrogen molecules would result in the highf0 /fs2 required 

to form magnetite and restrict gold mobilization. 

Molybdenum is dispersed under high fo lfs conditions and is deposited where sulfide ions are c~nc~ntrated 

both within copper ore bodies in PCD-Mo systems and 

within the peripheral pyrite zones around PCD-Au systems. 

This dispersal is expected in view of work by Cao and 

others (1988) showing that molybdenum can be transported 

as the complex Mo0Cl0 in solutions buffered by Fe30 4-

Fe20rFeS2 at 350 octo 400 oc and with NaCl concentrations of 0.1 to 4.5 M. These conditions are reasonable for 

the magnetite-bearing copper ore zone PCD-Au systems. 

In this paper we recognize an economically important 

intermediate type of gold- and molybdenum-rich copper 

deposits in which neither the gold dispersal nor the 

molybdenum dispersal process has worked effectively. 

Gold- Distribution of Gold in Porphyry Copper Deposits C9 
Cu 

•4 

.4 •4 

.a •4 

·6 

.2 

•6 ·2 

•1 

·3 

Mo x10 Au ppm 

Figure 8. Tonnage classes for porphyry copper deposits, which are defined in millions of metric tons as follows: 

1 = 0 to 50 5 = 401 to 800 

2 =51 to 100 6 = 801 to 1 ,600 

3 = 101 to 200 7 = 1,601 to 3,200 

4 = 201 to 400 8 = 3,201 to 6,400 

Correlation of gold content with tonnage is -0.42, which is significant at the 1-percent level. 

C1 0 Contributions to Commodity Geology Research 
Mo x10 

Cu 

.To ·Mg 

.Mg ·Mg 

• To 

•G::t 

·G::t 

.Qj 

Au ppm 

Figure 9. Type of ore-related intrusive rock in porphyry copper deposits. Mg, monzogranite; Gd, granodiorite; To, 

tonalite; Qd, quartz diorite, Mz, monzonite; Sy, syenite. 

Gold- Distribution of Gold in Porphyry Copper Deposits C11 
Alteration: Propylitic I Phyllic 

Mineralization: Molybdenite+ 

pyrite 

0.5 to 2 km 

Potassic ± propylitic overprint 

Magnetite + chalcopyrite + bornite 

+gold 

Phyllic Propylitic 

Molybdenite + 

pyrite 

Figure 10. Cross section of porphyry copper-gold deposit as typified by the Dos Pobres deposit in 

Arizona. Modified from Langton and Williams (1982). 

Alteration: Propylitic 

Mineralization: Pyrite 

Potassic± late 

phyllic overprint 

1 to 4 km 

Propylitic 

Skarn Cu-Au 

Figure 11. Cross section of a typical porphyry copper-gold-molybdenum deposit. 

C12 Contributions to Commodity Geology Research 
Alteration: Propylitic Potassic + late phyllic 

overprint 

Propylitic 

Mineralization: Pyrite Chalcopyrite+ pyrite 

+molybdenite 

Pyrite 

Intense fracturing and 

quartz-sulfide 

stockwork 

Figure 12. Cross section of a typical porphyry copper-molybdenum deposit. 

REFERENCES CITED 

Baldwin, J.T., Swain, H.D., and Clark, G.H., 1978, Geology and 

grade distribution of the Panguna porphyry copper deposit, 

Bougainville, Papua New Guinea: Economic Geology, v. 73, 

no. 5, p. 690-702. 

Cao, Xiaoyun, Richardson, S.M., and Richardson, C.K., 1988, 

Solubility of molybdenite (MoS2) in hydrothermal solutions: 

Geological Society of America Abstracts with Programs, v. 

20, no. 7, p. A43. 

Carson, D.J.T., Jambor, J.L., Ogryzlo, P., and Richards, T.A., 

1970, Bell copper-Geology, geochemistry and genesis of a 

supergene enriched biotized porphyry copper deposit with a 

superimposed phyllic zone, in Sutherland Brown, A., ed., 

Porphyry deposits of the Canadian Cordillera: Canadian 

Institute of Mining and Metallurgy Special Volume 15, p. 

245-263. 

Chaffee, M.A., 1982, A geochemical study of the Kalamazoo 

porphyry copper deposit, in Titley, S .R., ed., Advances in 

geology of the porphyry copper deposits, southwestern North 

America: Tucson, University of Arizona Press, p. 375-386. 

Cox, D.P., 1986, Geology of the Tanama and Helecho porphyry 

copper deposits and their vicinity, Puerto Rico: U.S. 

Geological Survey Professional Paper 1327, 59 p. 

Cox, D.P., Perez Gonzales, I., and Nash, J.T., 1975, Geology, 

geochemistry and fluid inclusion petrography of the Sapo 

Alegre porphyry copper prospect and its metavolcanic wallrocks, west central Puerto Rico: U.S. Geological Survey 

Journal of Research, v. 3, no. 3, p. 313-327. 

Cuddy, A.S., and Kesler, S.E., 1982, Gold in the Granisle and 

Bell porphyry copper deposits, British Columbia, in Levinson, A.A., ed., Precious metals in the Northern Cordillera: 

Rexdale, Ontario, Association of Exploration Geochemists, 

p. 157-172. 

Cummings, R.B., 1982, Geology of the Sacaton porphyry copper 

deposit, in Titley, S .R., ed., Advances in geology of the 

porphyry copper deposits, southwestern North America: 

Tucson, University of Arizona Press, p. 375-386. 

Henley, R. W., 1973, Solubility of gold in hydrothermal chloride 

solutions: Chemical Geology, v. 11, p. 73-87. 

Kesler, S.E., 1973, Copper, molybdenum and gold abundances in 

porphyry copper deposits: Economic Geology, v. 68, no. 1, 

p. 106--112. 

Langton, J.M., and Williams, S.A., 1982, Structural, 

petrological, and mineralogical controls for the Dos Pobres 

ore body, in Titley, S .R., ed., Advances in geology of the 

porphyry copper deposits, southwestern North America: 

Tucson, University of Arizona Press, p. 335-352. 

Nason, P.W., Shaw, A.V., and Aveson, K.D., 1982, Geology of 

the Poston Butte porphyry copper deposit, in Titley, S.R., 

ed., Advances in geology of the porphyry copper deposits, 

southwestern North America: Tucson, University of Arizona, 

p. 375-386. 

Popov, V. S., 1977, Geologiia i genezis medno- i molybdenporfirovykh mestorozhdenii (Geology and genesis of copperand-molybdenum-porphyry deposits): Akademiya Nauk 

SSSR, Ministerstvo geologii SSSR, Institut Mineralogii, 

geokhimii i kristallokhimii redkikh elementov; Isdatel'stvo 

"Nauka," Moskow, 203 p. [Translated for U.S. Geological 

Survey by Dorothy B. Vitaliano, May 1978.] 

Saegart, W.E., and Lewis, D.E., 1977, Characteristics of 

Philippine porphyry copper deposits and summary of current 

production and reserves: Transactions Society of Mining 

Engineers of AIME, v. 262, p. 199-209. 

Sillitoe, R.H., 1979, Some thoughts on gold-rich porphyry copper 

deposits: Mineralium Deposita, v. 14, p. 161-174. 

---1982, Unconventional metals in porphyry deposits: Society 

of Mining Engineers of AIME, preprint no. 82---63, 13 p. 

Gold- Distribution of Gold in Porphyry Copper Deposits C13 
Sinclair, A.J., Drummond, A.D., Carter, N.C., and Dawson, 

K.M., 1982, A preliminary analysis of gold and silver grades 

of porphyry-type deposits in western Canada, in Levinson, 

A.A., ed., Precious metals in the Northern Cordillera: 

Association of Exploration Geochemists, Rexdale, Ontario, 

p. 157-172. 

Streckeisen, A., 1973, Classification and nomenclature of plutonic rocks: Geologische Rundschau, v. 63, p. 773-786. 

Sutherland Brown, A., 1976, Morphology and classification, in 

Sutherland Brown, A., ed., Porphyry deposits of the CanaC14 Contributions to Commodity Geology Research 

dian Cordillera: Canadian Institute of Mining and Metallurgy 

Special Volume 15, p. 44-51. 

Taylor, D., and Van Leeuwen, T., 1980, Porphyry-type deposits 

in Southeastern Asia, in Ishihara, S. , and Takenouchi, S. , 

eds., Granitic magmatism and related mineralization: Mining 

Geology Special Issue, no. 8, p. 95-116. 

Wilkinson, W.H., Jr., Vega, L.A., and Titley, S.R., 1982, 

Geology and ore deposits at Mineral Park, Mohave County, 

Arizona, in Titley, S .R., ed., Advances in geology of the 

porphyry copper deposits, southwestern North America: 

Tucson, University of Arizona Press, p. 523-541. 
Chapter D 

Mercury-An Important Byproduct in 

Epithermal Gold Systems 

By JAMES j. RYTUBA and CHRIS HEROPOULOS 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract Dl 

Introduction Dl 

Byproduct Mercury Production Dl 

Mercury in Hot-Spring Systems D2 

Trace-Element Content of Vapor- and Fluid-Deposited Cinnabar DS 

Mercury in the Paradise Peak Mine D6 

References D8 

FIGURES 

1. Map showing location of epithermal precious-metal deposits that have produced 

byproduct mercury D2 

2. Schematic diagrams showing (A) distribution of mercury from degassing 

magmas, (B) hot-spring system features overprinted on the mercury flux from 

degassing magma, and (C) features of the waning stage of a hot-spring 

system D3 

3-7. Photomicrographs showing: 

3. Cinnabar from the Nody prospect adjacent to and above the Paradise Peak 

ore zone D6 

4. Vapor-deposited cinnabar and native sulfur overprinted on earlier hypogene 

ore, Paradise Peak deposit D6 

5. Antimony-iron-bismuth pseudomorphs after bismuthian stibnite D7 

6. A, Isometric dodecahedron crystals of corderoite from Paradise Peak deposit D7 

B, Corderoite from the McDermitt mercury deposit D7 

7. Silver-bearing cinnabar in association with quartz, Paradise Peak 

deposit D8 

TABLE 

1. Trace-element content of cinnabar deposited from vapor or fluid in 28 Nevada 

mercury deposits D4 

Contents Ill 

Mercury-An Important Byproduct in Epithermal 

Gold Systems 

By James J. Rytuba and Chris Heropoulos 

Abstract 

Mercury has been recovered as a byproduct from six 

sediment-hosted precious-metal deposits and three 

volcanic-related deposits in the Western United States. 

The largest byproduct mercury production comes from 

volcanic-related deposits; the Paradise Peak deposit in 

Nevada is the largest producer. Mercury generally occurs 

as cinnabar in sediment-hosted deposits, but mercury 

selenides and oxides have also been reported. In volcanicrelated systems, corderoite (Hg3S2CI 2 ) and (or) cinnabar 

are the main phases, and mercury oxides, chlorides, and 

silver mercury sulfides are also locally present. 

In epithermal gold systems, mercury can be transported in a fluid phase as Hg0 or Hgs= complex below the 

ground-water table and as a vapor above the ground-water 

table. Because mercury is the only ore metal that can be 

transported in significant amounts as a vapor, the traceelement content of cinnabar can be used to distinguish 

vapor-deposited cinnabar from fluid-deposited cinnabar. 

Cinnabar deposited from a vapor is chemically pure and 

contains very low amounts of trace elements (in ppm): 

antimony, ::::;15; arsenic, ::::;20; silver, <0.7; gold, ::::;0.5; 

copper, ::::;70; molybdenum, ::::;7; lead, ::::;30; tin, ::::;15; and 

zinc, ::::;200. Cinnabar deposited from a fluid has high 

concentrations of antimony (>150) or arsenic (>100 ppm); 

high-antimony samples contain 1-300 ppm silver, and 

high-arsenic samples contain 0.51 to 1 ppm gold. One or 

more of the base metals (copper, lead, zinc) generally 

exceeds concentrations of 300 ppm. 

During the evolution of a volcanic-related, epithermal system, mercury is initially introduced into the near 

surface by the degassing of an intrusive, and the resulting 

mercury geochemical anomaly is centered on the intrusive. In the subsequent development of a hydrothermal 

system, mercury is remobilized from the site of the 

geochemical anomaly and transported in the fluid phase 

as Hg0 or Hgs=. In the upper levels of the hydrothermal 

system, cinnabar and (or) mercurian-stibnite and (or) 

silver-mercury sulfide are deposited, and other ore elements within the solution are incorporated into the cinnabar structure. Above the ground-water table, chemically 

pure cinnabar is deposited from a vapor and occurs in 

association with kaolinite, alunite, and native sulfur (forming the "sulfurous type" of mercury deposit). During the 

waning stage of the system, lowering of the ground-water 

table exposes previously deposited sulfides to vapors 

continuing to effervesce from the hydrothermal system. In 

this oxidizing acid environment, mercurian stibnite is 

oxidized to antimony oxide, and the mercury released 

from the stibnite structure combines with H2S(g) and 

Cl2(g) effervescing from the hydrothermal solution to 

form corderoite. If Cl2 (g) is low, only cinnabar or mercury 

oxides will form. The Paradise Peak deposit records the 

entire complex record of mercury deposition expected in 

an epithermal system. 

INTRODUCTION 

Exploration for epithermal, precious-metal deposits 

in the Western United States has caused renewed interest in 

many inactive mercury deposits and occurrences. This 

interest has recently led to the discovery of precious metals 

in several mercury districts and has resulted in the production of mercury as a byproduct from many of these deposits. 

The recently discovered Paradise Peak gold-silver deposit in 

Nevada has become the second largest producer of mercury 

in the United States. The chemical behavior of mercury in 

epithermal systems is summarized in this paper, and the 

distribution of mercury in the Paradise Peak deposit is 

discussed in detail. 

BYPRODUCT MERCURY PRODUCTION 

Mercury occurs in trace to significant amounts in 

most epithermal precious-metal deposits. Mercury content 

of the precious-metal ore generally ranges from 0.1 to 50 

ppm (Bagby and Berger, 1985; Berger, 1985), but concentrations may vary considerably within individual deposits. 

Byproduct production from individual deposits ranges from 

10 to 350 flasks (a flask equals 76 pounds) of mercury per 

year. Volcanic-related and volcanic-hosted precious-metal 

deposits, especially those related to opalite-type mercury 

occurrences, produce considerably more byproduct mercury 

than sediment-hosted gold deposits. The largest U.S. producers of byproduct mercury are volcanic-related deposits: 

Paradise Peak, Nev., producing 350 flasks per year; 

Mercury-An Important Byproduct in Epithermal Gold Systems 01 
129. 125. 12r 11T 109. 1or 9T 

~r--~-----

1 / ---

WA I 

I 

I 

~- I -------.... '\. 

--;---------------r- 1 I 

I II 

MT ND I 4T I 

I \ 

OR \ ---{ ---------- ____ }------------- ---~ 

ID I 

39. 

;-------.1 

/ 4 -&-----.- 1 3 X sx I 

X X i 

I 

I 

1\ 2 7 / 

X I 

I 

I 

I 

I 

I 

\8 X '« \ NV I \ 

\ 

I 

I 

I 

CA 

9 

X 

UT 

SD I 

WY , I ____________ _ 

...., I '--,,~ 

/ ; 1 

L ____ r ___________ j ____ , \ 

I 

\ 

NE 

I 

I 

I 

I co 

;-- - - - - - - - - - - - - - -

I I --- 35. 

-----~------- ---r- _I 

3r 

I 

) 

/ 

r' 

\ 

-----y ..... 

1 

AZ NM 

I I I 

' I ~----J---------~ -----L-._j 

Figure 1. Location of epithermal precious-metal deposits that have produced byproduct 

mercury. 1, Mclaughlin; 2, Paradise Peak; 3, Pinson; 4, Preble; 5, Carlin; 6, Jerritt Canyon; 7, 

Alligator Ridge; 8, Borealis; and 9, Mercur. 

McLaughlin, Calif., producing 200 flasks per year; and 

Borealis, Nev., producing 4 flasks (fig. 1). Most sedimenthosted precious-metal deposits have produced byproduct 

mercury, but the production has been low, generally a few 

flasks per month. These deposits include Alligator Ridge, 

Carlin, Jerritt Canyon, Pinson, and Preble in Nevada and 

Mercur in Utah (fig. 1). 

In volcanic-hosted deposits, mercury occurs as 

cinnabar but may also be present as corderoite (Hg3S2Cl2), 

as mercury oxide, and in stibnite. Mercury in sedimenthosted deposits is generally present as cinnabar (Bagby and 

Berger, 1985; Radtke, 1985). In the Preble deposit, 

however, a mercury selenide and oxide as well as cinnabar 

have been identified (Raul Madrid, oral commun., 1989). 

MERCURY IN HOT-SPRING SYSTEMS 

In the hot-springs system models (see White and 

Roberson, 1962; Buchanan, 1981; White, 1981; Berger, 

02 Contributions to Commodity Geology Research 

1982, 1985; Berger and Eimon, 1983; and Henley and Ellis, 

1983), mercury is considered to be deposited at the surface 

and near-surface environment, with gold, arsenic, and 

antimony sulfides being deposited at deeper levels in the 

hydrothermal system (fig. 2). In near-surface hydrothermal 

systems, the position of the paleoground-water table is an 

important control on the deposition of mineral phases. 

Below the ground-water table, transport and deposition of 

ore metals occur in an aqueous phase. Above the groundwater table, transport and deposition occur from a vapor 

phase, except in areas where faults and fissures provide 

channels for fluid flow from the ground-water table to the 

surface. Unlike silver, gold, arsenic, antimony, and base 

Figure 2. A, Schematic distribution of mercury from ~ 

degassing magmas. 8, Hot-spring system features 

overprinted on the mercury flux from degassing magma. 

C, Features of the waning stage of a hot-spring system 

showing overprinting of vapor-dominated alteration and 

mercury deposition on earlier hypogene ore due to 

lowering of the paleoground-water table. 
A 

Fault 

I 

I 

/ , ' , 

\ 

.0 1 ppm Hg -- - -----: :_-_-_:- / 

0. 1 ppm Hg- _--------- / 

1 ppm Hg 

-

\ 

\ 

\ 

Surface 

\ Paleoground-water table ,-,~ \------------------

\ \ 

''<::::::,' ', '', 

' ', 

'0.1 ppm Hg 

', 1 ppm Hg 

,

2 ppm Hg--------, 

hyolite plug ' 

',2 ppm Hg 

B 

c 

Zone of opalite-type 

Hg formation, 

fluid deposition of Hg 

Zone of vapor deposition 

and acid alteration overprinted 

on earlier hypogene ore 

Surface 

Ve~s A~ A~ H~ A~ Sb 

V~ns A~ A~ H~ A~ Sb 

Au, Ag, As 

Mercury-An Important Byproduct in Epithermal Gold Systems 03 
Table 1. Trace-element content of cinnabar deposited from vapor or fluid in 28 Nevada mercury deposits 

[Analysis by emission spectroscopy. C. Heropoulos, analyst] 

Deposit Deposit type Ag As A Cu Mo Pb Sb Sn Zn 

Vapor-deposited ci a bar 

Buckskin Peak ......... Opalite ............... <0.7 2 <0.5 7 <2 <7 2 5 50 

Canyon Creek ......... Mafic volcanic ......... <.7 5 <.5 70 3 20 <1 <2 200 

Castle Peak ........... Opalite ............... <.7 2 <.5 50 <2 30 15 <2 70 

Cordero .............. Opalite ............... <.7 10 <.5 15 7 10 <1 <2 150 

Goldbanks ............ Opalite ............... <.7 <1 <.5 5 <2 30 15 <2 <15 

Red Rose ............. Opalite ............... <.7 <1 <.5 1.5 5 20 20 7 <15 

Ruby ................. Sedimentary ........... <.7 <1 <.5 3 <2 <7 15 <2 <15 

Thompson ............ Opalite ............... <.7 <1 <.5 7 <2 30 15 15 <15 

Fluid-deposited cinnabar 

A and B .............. Opalite ............... <0.7 500 

Antelope .............. Limestone ............ 2 15 

Cahill ................ Limestone ............ 7.0 30 

Governor ............. Opalite ............... 1.0 1.5 

Hagen Hegen .......... Opalite ............... 2.0 100 

M&M .............. Opalite ............... 1 150 

Mammoth ............. Sedimentary ........... 1 

McCoy ............... Sedimentary ........... .7 300 

Nevada Cinnabar ....... Opalite ............... 7.0 30 

Nevada Sulfur ......... Opalite ............... 1.5 3 

Nevada Quicksilver ..... Limestone ............ 5 70 

Pershing .............. Sedimentary ........... 2 7 

Red Bird RBI ......... Limestone ............ 7 10 

Red Bird RB2 ......... Limestone ............ 50 3 

San Pedro ............. Opalite ............... 300 700 

Steamboat Springs ...... Opalite ............... 5 <l 

Stockton .............. Opalite ............... 1 2 

Teapot ............... Opalite ............... 2 1,500 

White Caps ........... Sedimentary Au ........ 30 

Van Ness ............. Metamorphic .......... 2 200 

metals, mercury can be transported both below the groundwater table (in a hydrothermal fluid) and above the groundwater table (as a vapor). 

The control of the paleoground-water table on the 

deposition of ore elements has been documented at the 

Buckskin precious-metal deposit (Vikre, 1985) in Nevada. 

High-mercury contents occur above the paleoground-water 

table where mercury was deposited from a vapor and below 

the paleoground-water table where it was deposited from a 

fluid. High-silver, -gold, -arsenic, and -antimony contents 

are restricted to the zone below the paleoground-water 

table. 

Vapor transport and deposition of mercury above the 

ground-water table is common in many active hydrothermal 

systems (White, 1955, 1967, 1980). Significant vapor 

transport of H2S(g) also occurs above the ground-water 

table when H2S(g), Hg0

(g), Cl(g), and other volatile 

elements are boiled off from the hydrothermal system. 

Oxidation of H2S(g) by atmospheric oxygen leads to 

deposition of native sulfur, and mercury vapor reacts with 

sulfur to form cinnabar. Hydrolysis of native sulfur forms 

04 Contributions to Commodity Geology Research 

<0.5 20 150 15 <2 30 

<.5 .7 <2 15 300 <2 <15 

2.0 50 <2 10 500 15 1,000 

<.5 <.7 50 30 70 150 <15 

<.5 7 <2 50 200 3 20 

.5 100 <2 30 100 <2 30 

7 <2 15 15 <2 20 

<.5 20 <2 150 700 <2 300 

<.5 10 <2 50 200 30 <15 

<.5 5 <2 15 150 15 70 

<.5 15 <2 10 300 >2 30 

1.0 5 <2 300 300 <2 2,000 

<.5 3 <2 300 700 <2 300 

<.5 1,000 5 >50,000 >50,000 7 >50,000 

<.5 500 20 15,000 300 70 7,000 

<.5 700 <2 70 150 7 70 

<.5 7 3 10 150 <2 <15 

<.5 7 3 20 500 3 30 

<.5 30 2 70 1,000 <2 1,000 

<.5 7 7 <7 50 3 50 

sulfuric acid, which subjects the host rock to acid alteration 

that results in an alteration assemblage of cristobalite, 

opaline silica, kaolinite, alunite±quartz, commonly termed 

acid-leached rock (White and Roberson, 1962). The 

"sulfurous type" of mercury deposit originally proposed by 

Bailey and Phoenix (1944) is formed in this chemical 

environment, as is the upper part of the "opalite-type" 

mercury deposit. The sulfur in many opalite-type deposits, 

however, has been removed by surface waters during 

weathering of these deposits. The lower part of opalite-type 

mercury deposits forms below the ground-water table where 

silicification can be pervasive along particularly permeable 

strata. These opalite-type deposits are distinguished from 

those formed above the ground-water table by the absence 

of vapor-deposited minerals and the presence of hydrothermal sulfides. 

Cinnabar deposited from a vapor above the groundwater table is chemically pure. The trace-element 

characteristics of cinnabar deposited from a vapor, as 

compared to cinnabar deposited from a fluid, are discussed 

in the following section. Below the ground-water table, 
mercury is transported as native mercury in solution 

(Varekamp and Buseck, 1984) or as a mercury bisulfide 

complex (Dickson and Tunell, 1967). The various mercury 

transport mechanisms are summarized by Rytuba (1985). 

The high solubility of Hg0 and mercury-sulfide complexes, 

even at low temperatures, results in deposition of cinnabar 

in the upper part of the hydrothermal system and at the 

surface in hot-spring sinter. Ore elements transported along 

with mercury in the hydrothermal fluid are incorporated into 

the cinnabar mineral structure during deposition of 

cinnabar. Cinnabar deposited from a fluid is generally 

chemically impure and contains significant contents of trace 

elements. 

In areas where volcanic activity precedes or is 

contemporaneous with the development of a hot-spring 

system, the distribution of mercury will be complex and 

reflect both vap~r-deposited and fluid-deposited mercury. 

When volcanic activity precedes development of a hotspring system, a mercury flux from degassing magma will 

spread outward into the country rock to develop a broad 

mercury anomaly having highest mercury contents 

immediately above the magma source (fig. 2A). Varekamp 

and B useck ( 1986) summarized the magnitude of the mercury 

flux for passively degassing magmas and active volcanoes. 

The subsequently developed hydrothermal system will be 

superimposed on the mercury anomaly related to magma 

degassing. Mercury will be remobilized, concentrated in the 

hydrothermal system, and deposited in the upper level of 

the hot-spring system from a fluid phase and above the 

ground-water table from a vapor phase (fig. 2B). Lowering 

of the paleoground-water table during the waning stage of 

hydrothermal activity will expose previously deposited 

hypogene ore to volatiles boiling off from the residual 

hydrothermal fluid. Oxidation and alteration of the hypogene ore will occur at the same time that mercury is 

transported and deposited from the vapor phase. The 

overprinting of this late stage of vapor-deposited mercury 

on earlier hypogene ore is common in many hot-springrelated deposits. The geochemical distribution of mercury 

in hot-spring systems is therefore complex and reflects the 

cumulative effect of multiple events developed over the 

duration of volcanic and hydrothermal activity. 

TRACE-ELEMENT CONTENT OF VAPOR- AND 

FLUID-DEPOSITED CINNABAR 

Cinnabar can incorporate significant amounts of trace 

elements in its mineral structure. These elements include 

silver, arsenic, gold, copper, molybdenum, lead, tin, 

antimony, and zinc. Cinnabar deposited from a fluid 

transporting these elements will contain varying amounts of 

an element depending on the concentration of the element in 

the fluid phase. Cinnabar is an effective monitor of whether 

a fluid is carrying a particular element, such as silver or 

gold, even if the chemical and (or) physical conditions do 

not cause silver or gold to precipitate at the level or time of 

cinnabar deposition. In contrast, cinnabar deposited from a 

vapor is chemically pure and has very low contents of trace 

elements. The trace-element content of cinnabar can be 

used to distinguish between vapor-deposited cinnabar and 

fluid-deposited cinnabar. 

Cinnabar mineral separates from 28 different mercury 

deposits in Nevada were analyzed by quantitative spectrographic analysis. Data for five mercury deposit typesopalite, limestone-hosted, clastic sediment-hosted, mafic 

volcanic-hosted, and metamorphic-hosted-are listed in 

table 1. 

Cinnabar deposited from a vapor occurs in two 

deposit types: opalite and clastic sediment-hosted. Vapordeposited cinnabar separates have very low concentrations 

of trace elements (in ppm): Ag (<0.70), As (:520), Au 

(:50.5), Cu (:570), Mo (:57), Pb (:530), Sb (:515), Sn 

(:515), and Zn (:5200). 

In contrast, cinnabar deposited from a hydrothermal 

fluid occurs in all five mercury deposit types and is 

characterized by high concentrations of antimony, greater 

than 150 ppm, and (or) arsenic, greater than 100 ppm. All 

cinnabar samples having high antimony contents contain 

from 1 to 300 ppm silver, and if arsenic content is high, 

gold is characteristically present in the range of 0.5 to 1 

ppm. Base-metal contents in fluid-deposited cinnabar are 

generally in the same range as vapor-deposited cinnabar 

except for cinnabar having high silver content (>5 ppm). In 

these samples either lead, zinc, or copper exceeds 300 ppm. 

Tin and molybdenum values are comparable to those in 

vapor-deposited cinnabar except for two opalite-type 

deposits contammg high tin (70-150 ppm) and 

molybdenum (20-50 ppm). 

Trace-element analysis of cinnabar may prove useful 

in precious-metal exploration where identification of the 

paleoground-water table is important in defining the level at 

which precious metals are deposited. Chemically pure 

cinnabar indicates that the samples are from the zone of 

vapor transport and deposition and that precious-metal 

deposition occurred at a lower level. Analysis of fluiddeposited cinnabar could indicate whether silver and (or) 

gold were present in the hydrothermal solution as well as 

indicate the concentration of precious metals. The presence 

of appreciable silver and gold in cinnabar but not in the host 

rock indicates that these elements were deposited either 

above the level of cinnabar deposition or laterally away 

from the cinnabar in cases where fluid flow was confined to 

an aquifer. Systematic sampling of cinnabar from various 

levels indicates the direction of fluid flow because traceelement content decreases as fluids move from the source 

area. Trace-element analysis of cinnabar separates is more 

effective in geochemical prospecting than whole-rock 

analysis because the whole-rock chemistry records the 

cumulative effects of the mineralization event as it 

developed through time. 

Mercury-An Important Byproduct in Epithermal Gold Systems 05 
Figure 3. Cinnabar from the Nody prospect adjacent to 

and above the Paradise Peak ore zone. Assemblage 

consists of vapor-deposited cinnabar, with alunite and 

quartz (occurrence type 1). 

MERCURY IN THE PARADISE PEAK MINE 

The Paradise Peak mine, located 14 km south of 

Gabbs, Nev., began production in 1986. With reserves of 

1.1 million oz of gold and 30 million oz of silver, the 

deposit ranks seventh in gold reserves in the United States. 

It is the second largest producer of mercury in the United 

States. Mercury production averages about 1 metric ton (29 

flasks) per month, and reserves are estimated to be about 

3,000 flasks. More recent estimates suggest mercury 

production could increase to 800 to 2,600 flasks per year 

(Carrico, 1986). 

The deposit has characteristics similar to those of 

many hot-spring-type gold deposits. The ore is hosted by 

pervasively silicified ash-flow tuff and andesite of midTertiary age. Above the ore zone, the tuff is altered to an 

assemblage of alunite, kaolinite, and quartz. Gold is present 

as the native element, and silver occurs primarily as 

cerargyrite, acanthite, and native silver (Thomason, 1986; 

John and others, 1989). Within the deposit, mercury occurs 

in several phases and in several different environments, 

which include ( 1) cinnabar in association with kaolinite and 

alunite above the ore horizon, (2) cinnabar associated with 

sulfur in the ore zone, (3) corderoite as an oxidation product 

of stibnite in the ore zone, and (4) cinnabar containing 

appreciable silver in the ore zone. 

Prior to discovery of the Paradise Peak gold deposit, 

sporadic exploration work occurred on the property, 

principally in the area around the Nody mercury prospect. 

The prospect occurs just above the gold ore zone and 

consists of sparse disseminations of cinnabar (occurrence 

type 1) in volcanic rock completely altered to kaolinite, 

D6 Contributions to Commodity Geology Research 

Figure 4. Vapor-deposited cinnabar and native sulfur 

overprinted on earlier hypogene ore, Paradise Peak 

deposit (occurrence type 2). 

alunite, and quartz (fig. 3). Sulfur is present in vugs within 

the more silicified rock. The occurrence is typical of 

cinnabar deposits formed in hot-spring systems above the 

ground-water table through vapor transport of mercury. The 

cinnabar is chemically pure and contains no gold or silver, 

either in the cinnabar or in acid-leached host rock. 

Interestingly, the shaft within the old mercury prospect was 

stopped just 12 m above the gold ore zone. 

Within the gold ore zone, cinnabar occurs with native 

sulfur (occurrence type 2) in cavities that occur within the 

silicified tuff. Crystals of chemically pure cinnabar, up to 

10 J.Lm in diameter, are disseminated throughout the native 

sulfur (fig. 4). The cinnabar-sulfur assemblage formed late 

in the paragenetic sequence as evidenced by its presence 

only in cavities developed within previously silicified and 

mineralized tuff. The presence of sulfur and chemically 

pure cinnabar indicates that deposition occurred from a 

vapor. During the waning stage of the hydrothermal system, 

the paleoground-water table was lowered, exposing hypogene ore to vapor boiling off from the hydrothermal fluid. 

Mercury vapor and H2S(g) were transported through the 

few remaining spaces present in the silicified tuff. 

Oxidation of H2S(g) by atmospheric oxygen resulted in 

deposition of native sulfur, which reacted with mercury 

vapor to form cinnabar. The process is identical to that 

which formed cinnabar in occurrence type 1 except that it is 

overprinted on an earlier hypogene mineralization deposited 

from a hydrothermal fluid. 

The major occurrence of mercury in the ore zone is as 

corderoite, occurrence type 3. Corderoite, Hg3S2Cl2 , is an 

extremely rare mineral, previously recognized only at two 

other localities: the McDermitt mercury mine, Nev., where 
Figure 5. Antimony-iron-bismuth pseudomorphs after bismuth ian stibnite. White crystals are corderoite, Hg352CI2 

(occurrence type 3). 

It IS the main ore mineral, and at the Aizak mercury 

prospect in Tuva, U.S.S.R. (Vasil'ev and others, 1984). 

The corderoite at Paradise Peak occurs in association with 

an Sb-Bi-Fe oxide (an unnamed new mineral), which 

typically forms as pseudomorphs after stibnite (fig. 5). The 

corderoite occurs as isometric, dodecahedron crystals 

ranging from 1 to 5 in diameter (fig. 6A), which are 

identical to those present at the McDermitt mine (fig. 6B). 

The Sb-Bi-Fe-oxide is an oxidation product of stibnite that 

was deposited along fractures and in vugs with quartz 

during the early phase of hypogene mineralization. The 

stibnite contains appreciable bismuth in solid solution 

(Thomason, 1986) and mercury, indicating that both these 

elements were present in the ore-forming solution. During 

oxidation of the stibnite, mercury was released and reacted 

with native sulfur and Cl2(g) to form corderoite. Oxidation 

of the stibnite occurred during the waning stage of the 

hydrothermal activity when the paleoground-water table 

was lowered exposing the hypogene ore to atmospheric 

oxygen and Cl2 (g) boiling off from the hydrothermal fluid. 

The fourth occurrence type consists of silver-bearing 

cinnabar intergrown with quartz in the ore zone (fig. 7) and 

is quite rare. The cinnabar occurs as crystals up to 2 J..Lm in 

diameter. The molecular ratio of silver to mercury in the 

cinnabar is variable and is as high as 1. The presence of 

silver in the cinnabar and its association with quartz indicate that it was deposited from a hydrothermal fluid 

rather than a vapor. 

In summary, a variety of mercury phases occur at the 

Paradise Peak mine. During the hypogene stage of 

mineralization, mercury was deposited with stibnite in solid 

solution and as cinnabar containing variable amounts of 

A 

B 

Figure 6. A, Isometric dodecahedron crystals of corderoite 

from Paradise Peak deposit. B, Corderoite from the 

McDermitt mercury deposit (occurrence type 3). 

silver. During the waning stage of hydrothermal activity, 

lowering of the paleoground-water table exposed hypogene 

ore to vapor H2S(g) and Cl(g), Hg0

(g) boiling off from the 

remaining hydrothermal fluid. Oxidation of H2S(g) resulted 

in the formation of native sulfur, which reacted with 

mercury vapor to form chemically pure cinnabar. Oxidation 

of stibnite released mercury, which reacted with native 

sulfur and chlorine vapor to form corderoite. 

Mercury occurrences in the Paradise Peak deposit are 

an excellent example of the diverse processes that typically 

deposit mercury in epithermal gold systems. The 

distribution of mercury in these deposits reflects the 

Mercury-An Important Byproduct in Epithermal Gold Systems 07 
Figure 7. Silver-bearing cinnabar in association with 

quartz, Paradise Peak deposit (occurrence type 4). Darker 

gray cinnabar crystals contain highest Ag: Hg. 

cumulative effect of these processes. Because only some 

stages of mercury deposition occur concurrently with gold 

or silver deposition, the use of whole-rock mercury for 

analysis in geochemical exploration should be done with 

caution. 

REFERENCES 

Bagby, W.C., and Berger, B.R., 1985, Comparative anatomy of 

sediment-hosted epithermal precious-metal deposits, in 

Berger, B.R., and Bethke, P.M., eds., Geology and geochemistry of epithermal systems: Reviews in Economic 

Geology, v. 2, p. 169-202. 

Bailey, E.H., and Phoenix, D.A., 1944, Quicksilver deposits in 

Nevada: University of Nevada Bulletin, v. 30, no. 5, 206 p. 

Berger, B.R., 1982, The geological attributes of Au-Ag-base 

metal epithermal deposits, in Erickson, R.L., ed., 

Characteristics of mineral deposit occurrences: U.S. 

Geological Survey Open-File Report 82-795, p. 119-126. 

---1985, Geologic-geochemical features of hot-spring 

precious-metal deposits, in Tooker, E.W., ed., Geologic 

characteristics of sediment- and volcanic-hosted disseminated 

gold deposits-Search for an occurrence model: U.S. 

Geological Survey Bulletin 1646, p. 47-54. 

Berger, B.R. , and Eimon, P.I., 1983, Conceptual models of 

epithermal precious metal deposits, in Shanks, W.C., ed., 

Cameron volume on unconventional mineral deposits: 

American Institute of Mining, Metallurgical and Petroleum 

Engineers, p. 191-205. 

Buchanan, L.J., 1981, Precious metal deposits associated with 

volcanic environments in the southwest, in Dickinson, W .R., 

08 Contributions to Commodity Geology Research 

and Payne, W. D. , eds. , Relations of tectonics to ore deposits 

in the southern cordillera: Arizona Geological Society Digest, 

v. 14, p. 237-261. 

Carrico, L.C., 1986, Mercury: U.S. Bureau of Mines Minerals 

Yearbook, v. 1, p. 683-689. 

Dickson, F.W., and Tunell, G., 1967, Mercury and antimony 

deposits associated with active hot-springs in the western 

United States, in Ridge, J.D., ed., Ore deposits of the United 

States, 1933-1967, Graton-Sales volume: American Institute 

of Mining, Metallurgical and Petroleum Engineers, v. 2, p. 

1673-1701. 

Henley, R.D., and Ellis, A.J., 1983, Geothermal systems ancient 

and modern-A geochemical review: Earth-Science 

Reviews, v. 19, p. 1-50. 

John, J.A., Thomason, R.E., and McKee, E.H., 1989, Geology 

and potassium-argon geochronology of late Cenozoic volcanism, tectonism, and precious-metal mineralization in Paradise 

Peak mine area west-central Nevada: Economic Geology, v. 

84, p. 631-649. 

Radtke, A.S., 1985, Geology of the Carlin gold deposit, Nevada: 

U.S. Geological Survey Professional Paper 1267, 124 p. 

Rytuba, J.J., 1985, Geochemistry of hydrothermal transport and 

deposition of gold and sulfide minerals in Carlin-type gold 

deposits, in Tooker, E.W., ed., Geologic characteristics of 

sediment- and volcanic-hosted disseminated gold depositsSearch for an occurrence model: U.S. Geological Survey 

Bulletin 1646, p. 27-34. 

Thomason, R.E., 1986, Geology of the Paradise Peak gold/silver 

ore deposit, Nye County, Nevada, in Tingley, J. V., and 

Bonham, H.F., eds., Precious-metal mineralization in hot 

spring systems, Nevada-California: Nevada Bureau of Mines 

and Geology Report 41, p. 90-92. 

Varekamp, J.C., and Buseck, P.R., 1984, The speciation ofHg in 

hydrothermal systems, with application for ore deposition: 

Geochimica et Cosmochimica Acta, v. 48, p. 177-185. 

---1986, Global mercury flux from volcanic and geothermal 

sources: Applied Geochemistry, v. 1, p. 65-73. 

Vasil'ev, V.I., Pal'chick, N.A., and Grechischev, O.K., 1984, 

Lavrentievite and Arkazite-New natural mercury sulfohalides: Geologiya i Geofizika, v. 25, no. 7, p. 54-73. 

Vikre, P. G. , 1985, Precious-metal vein systems· in the National 

district, Humboldt County, Nevada: Economic Geology, v. 

80, no. 2, p. 360-393. 

White, D.E., 1955, Thermal springs and epithermal ore deposits: 

Economic Geology, 50th Anniversary Volume, p. 99-154. 

---1967, Mercury and base-metal deposits with associated 

thermal and mineral waters, in Barnes, H.L., ed., Geochemistry of hydrothermal ore deposits: New York, Holt, 

Rinehart, and Winston, Inc., p. 575-631. 

---1980, Steamboat Springs geothermal area: Society of 

Economic Geologists Epithermal Deposits Field Conference, 

1980, Field Trip Guidebook, p. 44-51. 

---1981, Active geothermal systems and hydrothermal ore 

deposits, in Skinner, B .J., ed.: Economic Geology, 75th 

Anniversary Volume, p. 392-423. 

White, D.E., and Roberson, C.E., 1962, Sulphur Bank, 

California, a major hot-spring quicksilver deposit: Geological 

Society of America Buddington Volume, p. 397-428. 
Chapter E 

Nickel-Mineralogy and Chemical 

Composition of Some Nickel-Bearing 

Laterites in Southern Oregon and Northern 

California 

By MICHAEL P. FOOSE 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract El 

Introduction El 

General Setting El 

Sample Description and Treatment E3 

Laterite Mineralogy ES 

Chemical Variations E13 

Discussion E16 

Conclusions E21 

References E23 

FIGURES 

1. Index and sample location map E2 

2, 3. Graphs showing: 

2. X-ray mineralogy and chemistry for profile from site 216 Ell 

3. X-ray mineralogy and chemistry for profile from site 233 E14 

4, 5. Plots of: 

4. MgO vs. Si02 contents E17 

5. Fe20 3 vs. MgO contents E17 

6. Graph showing stability of some minerals found in laterites plotted as log 

(Mg++) + 2pH vs. log (H4Si04) El9 

7-9. Plots of: 

7. Al20 3 vs. Ti02 contents El9 

8. Al20 3 vs. Fe20 3 contents E20 

9. Nickel vs. cobalt contents E21 

TABLES 

1. Analyses from 11 laterites E4 

2. Mineralogical and chemical summary ES 

3. Range of laterite compositions E9 

4. Correlation of abundance of elements, oxides, and minerals E17 

5. Net change in laterite composition E22 

Contents Ill 

Nickel- Mineralogy and Chemical Composition of 

Some Nickel-Bearing Laterites in Southern Oregon 

and Northern California 

By Michael P. Foose 

Abstract 

The mineralogy and chemistry of 109 samples from 

11 nickel-bearing laterites located in southern Oregon and 

northern California were determined. The laterites are 

primarily composed of serpentine, chlorite, goethite, and 

maghemite. Some contain additional minor amounts of 

smectite, quartz, talc, hornblende, orthopyroxene, and 

tremolite. Smectite (possibly nontronite) occurs only in 

laterites located on hillslopes and appears to be restricted 

to areas where ground water may have been enriched in 

Si02 and MgO from downslope flow across bedrock. 

Nickel content of the laterites averages 0.64 weight percent but varies between 0.45 and 1.4 weight percent; 

cobalt averages 0.06 weight percent and ranges between 

0.03 and 0.15 weight percent. Neither nickel nor cobalt has 

predictable distributions. In contrast, patterns made by 

major elements follow trends defined by relatively simple 

chemical models. Calculated net changes in laterite chemistry indicate that the mobility of components is, from 

most depleted to least, MgO, Si02 , nickel, MnO, Fe20 3 , 

and cobalt. These calculations also show that only a few of 

the laterites have significant amounts of net enrichment in 

either nickel or cobalt. 

INTRODUCTION 

The United States is import-dependent for a number 

of important commodities, among which are nickel and 

cobalt. Several potentially important domestic deposits 

containing these elements have been identified. Of these, 

the most important are the magmatic sulfides in the Stillwater Complex (Montana) and the Duluth Complex (Minnesota), the sediment-hosted and strata-bound Cu-rich sulfides and arsenides of the Blackbird deposit (Idaho), 

Mississippi Valley-type lead deposits (southeast Missouri), 

and the nickel-bearing laterites in Oregon and northern 

California (Foose, 1991). Although one of these, a nickel 

laterite located near Riddle, Oreg., was recently mined (fig. 

1), none of these deposits are currently in production.Other 

nickel-bearing laterites occur in southern Oregon and northem California, and several of these have recently been 

examined as potential additional sources of nickel and 

byproduct cobalt. This study looks at some of the mineralogical and chemical features associated with several of 

these occurrences. 

GENERAL SETTING 

The nickel laterite deposits in Oregon and northern 

California occur over ophiolites that are part of several 

different accreted terranes. As a result of the accretionary 

processes by which these terranes were affixed to the 

western margin of the United States, these ophiolitic rocks 

now form subparallel belts that range in age from Paleozoic 

(easternmost) to upper Jurassic (westernmost) (Irwin, 

1977). Subsequent to emplacement, many of these ophiolitic bodies were exposed to extensive weathering that 

resulted in formation of laterites. There is some uncertainty 

as to the exact age of weathering. Most probably occurred 

during the Miocene formation of the Klamath peneplain 

(Diller, 1902). Some weathering, however, was much 

younger, as shown by the occurrence of laterite on Pleistocene terraces (Hotz, 1964; Moring, oral commun., 1986). 

Subsequently, most laterites have been uplifted and dissected so that many now occur on plateaus or as cappings on 

ridges and saddles and as transported debris on sides of hills 

and in valleys. 

Nickel laterites similar to these are a common product 

of tropical weathering of ultramafic rocks. They, in fact, 

constitute the world's largest land-based resource of nickel 

(Chamberlain, 1986). The features associated with these 

deposits have been reviewed by a number of authors, most 

notably Trescases (1975), Evans and others (1979), and 

Golightly (1981). Features typical of laterite profiles from 

this area are reported as follows: Upper parts of laterite 

profiles consist of an extensively leached iron-rich zone 

(limonitic zone) that is dark reddish brown in color; iron 

oxide pellets locally occur near the profile top. This reddish 

zone grades downward into a yellow-brown zone (saprolitic 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites E1 
A B /,-~Riddle 

/ t.__Laterite 

I 

X Mount 

Emily 

\('j) 

.3 

)~ OREGON 

------------r------------

.) ~ CALIFORNIA 

( 

...... 

,.J 

/ 

-~ / / 

I / ( 

~-, \ 23~--- Jl!ff99 . ._/ '-1. Gasquet l · f \ Mountain xt ( ,.J ..,,\le1 

. C/) 232 . .231 -· "\." ~\ l~·\ 1.1 . _( • ./ 511'\ 

·-r ) ::> ~- _., .......... ~e ro1\<. 

I .l ~- )(( ~w~o: J ·\...~e,.. 

11-- "") . 0 

// (~). -. f------.-----'-----.-----' 

\.... 0 10 KILOMETERS 

10 MILES 

't 

Figure 1. A, Approximate area of the northern California-southern Oregon 

laterite district (dashed boundary). B, Sample sites (solid diamonds). Shaded 

area represents approximate boundary of the Kalmiopsis Wilderness area. 

E2 Contributions to Commodity Geology Research 
zone) in which there commonly are pieces of partly 

weathered peridotite and in which the degree of 

preservation of relict bedrock structures increases with 

depth. The saprolite zone grades into greenish-brown 

weathered peridotite and then into fresh peridotite or 

serpentine (Hotz, 1964; Ramp, 1978). 

In some laterites, nickel occurs in the lower saprolitic 

zone as a solid solution replacement of magnesium in a 

variety of secondary magnesium silicates (mostly serpentine, talc, and chlorite). These nickel-magnesium silicates 

are referred to as the "garnierite group" (Faust, 1966) and 

form what are commonly known as either saprolite or 

silicate ores. Nickel content of these ores typically is 

between 2 and 3 percent. In contrast, nickel in the overlying 

limonitic zone occurs mostly in goethite and rarely exceeds 

2 percent. Significant amounts of cobalt also occur in many 

laterites and are associated mostly with manganese oxides 

( asbolite) that are concentrated in the lower part of the 

limonitic soil zone. 

In Oregon and northern California, laterites having an 

extensively developed nickel-bearing silicate zone are 

known to occur only near Riddle, Oreg. Saprolite is present 

in other deposits but generally does not contain significant 

amounts of gamierite-type mineralization. The reason for 

the apparent restriction of higher grade nickel ores to the 

Riddle area is not clear, but Hotz ( 1964) speculates that 

rocks associated with this deposit may have had a longer 

weathering history. As a result of its higher nickel grades, 

the deposit near Riddle was the first to be developed. 

In addition to its relatively greater nickel content, the 

ores at Riddle also contain relatively high amounts of silica 

and magnesium. As a result of this composition, refining 

must be done by pyrometallurgical processes (Canterford, 

1975). The product was ferronickel containing about 49 

percent nickel; cobalt was not recovered separately. In 

contrast, the lower Si02 and MgO contents of limonitic ores 

commonly allow them to be refined by a variety of 

hydrometallurgical techniques, many of which enable 

recovery of both nickel and cobalt. Specific processes 

designed to extract both nickel and cobalt from the 

relatively low grade laterites in northern California and 

Oregon have been developed and tested (Siemens and 

others, 1975; Duyvesteyn and others, 1979; Kukura and 

others, 1979), and, for this reason, several of these deposits 

have been evaluated as possible domestic sources of both 

nickel and cobalt. 

SAMPLE DESCRIPTION AND TREATMENT 

Samples from several laterite deposits were collected 

as part of a program to evaluate the mineral resources of the 

Kalmiopsis Wilderness (Page and others, 1982; fig. 1). 

Sample sites were both within or near the wilderness area 

and from an adjacent area, near Gasquet Mountain, Calif. 

This latter area contains several laterite deposits that may be 

commercially usable. Samples from the Gasquet Mountain 

area were collected from prospect pits in which profiles as 

thick as 7 m were exposed. In contrast, other samples were 

collected with a hand auger and, because of the limitations 

of this device, seldom penetrated more than 2 to 3 m of 

laterite. In eight cases, this amount of penetration was 

sufficient to sample profiles that exhibited all the features 

found in the more completely exposed pits as well as to 

show the same features that have been described for other 

laterites in this region (Hotz, 1964; Ramp, 1978). Samples 

collected from these eight locations as well as those taken 

from the exploration pits provide the material discussed in 

this report. 

One hundred laterite samples and nine rock samples 

were analyzed for nickel, cobalt, copper, and 10 major 

oxides. Results are given in table 1. In addition, the 

mineralogy of samples was determined by X-ray diffraction. Samples were ground to less than 325 mesh and then 

pressed into circular wafers. Wafers were made by placing 

the ground material on a layer of boric acid and methyl 

cellulose, a compound added to provide strength. This 

mixture was compressed in a hydraulic press for at least 30 

seconds at a pressure of 10,000 pounds per square inch. 

Wafers were then exposed to CuKa 1 radiation by using a 

1.0° beam slit, a 0.1 o detection slit, a crystal monochrometer, and a proportional counter detector. The samples were 

scanned between 2° and 60° 28 at a rate of 1/2° 28/minute. 

In order to resolve some ambiguous mineralogical 

identifications, several samples received further treatment. 

Splits from these were suspended in water and then allowed 

to settle onto porcelain tiles, a procedure which oriented the 

clay-size fraction. Four X-ray diffraction patterns, between 

2° and 18° 28, were made of the clay fraction; first, after the 

samples had been air dried; second, after the samples were 

treated with ethylene glycol (EG) for at least 1 hour; third, 

after the samples had been heated to 350 oc for at least 1 

hour; and fourth, after heating the samples to 550 oc for at 

least one hour. 

This procedure enables the distinction of smectite 

from chlorite and vermiculite and the distinction of serpentine from kaolinite. Mineral identification is based on the 

following responses (Grim, 1968; Hathaway, unpublished 

report): 

Upon treatment with EG, the 14-A peak of smectite 

expands to 17 A, while the 14-A peaks of chlorite and (or) 

vermiculite are essentially unchanged. 

Upon heating to 350 °C, the 14-A peak of smectite 

collapses to 10 A, while the chlorite and (or) vermiculite 

14-A peak is unchanged. 

Upon heating to 550 °C, the 14-A peak of chlorite 

may increase in intensity, the 14-A peak of vermiculite 

collapses to 10 A, and the 7-A peak of serpentine remains 

stable, while the 7-A peak of kaolinite is usually destroyed. 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites EJ 
Table 1. Analyses from 11 laterites 

[Locations of profile sample numbers are shown in figure 1; depth is in meters below surface. Nickel, cobalt, and copper are given in parts per million 

(J.S. Wahlberg, J. Baker, and J. Taggart, analysts). Mineralogy was determined by X-ray diffraction; numbers represent qualitative estimates of relative 

Site/Sample 

number 

Sample 

depth (m) Sample type Chlorite Serpentine Goethite Maghemite Quartz Smectite Talc Ortho- Tremolite Hornpyroxene blende 

211-1. ....... 0.23 ....... red-brown 

211-2. . . . . . . . .38 . . . . . . . gray-yellow 

211-3 . . . . . . . .64 . . . . . . . gray-yellow 

211-4. . . . . . . . .92 . . . . . . . gray-yellow 

211-5. . . . . . . . 1.22 . . . . . . . gray-yellow 

211-6 1.53 . . . . . . . gray-yellow 

211-7 . . . . . . . 1.83 . . . . . . . gray-green 

211-8 . . . . . . . 2.14 . . . . . . . gray-green 

211-9... . . . . . . . . . . . . . . . . rock 

213-1........ .15 . . . . . . . red-brown 

213-2 . . . . . . . .31 . . . . . . . red-brown 

213-3. . . . . . . . .61 . . . . . . . green-gray 

213-4. . . . . . . . .92 . . . . . . . black 

213-5 . . . . . . . 1.22 . . . . . . . black 

213-6. . . . . . . . 1.53 . . . . . . . yellow-green 

213-7 . . . . . . . 1.88 . . . . . . . green-black 

213-8 . . . . . . . . . . . . . . . . . . . rock 

214-1. ... 0 0 •• 

214-2 ...... 0 0 

214-3 ....... . 

214-4 ....... . 

.15 . . . . . . . red-brown 

.31 . . . . . . . red-brown 

.61 . . . . . . . yellow-green 

.92 . . . . . . . yellow-green-black 

214-5...... . . 1.22 . . . . . . . green-black 

214-6. . . . . . . . 1.37 . . . . . . . green-black 

214-7...... . . . . . . . . . . . . . rock 

215-1 . . . . . . . .15 ....... red-brown 

215-2. . . . . . . . .31 . . . . . . . red-brown 

215-3 . . . . . . . .61 . . . . . . . dark-red-brown 

215-4. . . . . . . . .92 . . . . . . . yellow-green 

215-5. . . . . . . . 1.22 . . . . . . . yellow-green 

215-6 . . . . . . . . . . . . . . . . . . . rock 

216-1 ...... 0 

216-2 ....... . 

216-3 ...... . 

216-4 ....... . 

.15 . . . . . . . red-brown 

.31 . . . . . . . red-brown 

.61 . . . . . . . yellow-brown 

.92 . . . . . . . yellow-brown 

216-5 . . . . . . . 1.22 . . . . . . . yellow-brown 

216-6...... . . . . . . . . . . . . . rock 

217-1. ...... . 

217-2 .. 0 ••••• 

217-3 

217-4 

217-5 

217-6 

.15 . . . . . . . dark-red-brown 

.31 . . . . . . . red-brown 

.61 . . . . . . . green-gray 

.92 . . . . . . . green-gray 

1.22 . . . . . . . green-gray 

1.53 . . . . . . . green-gray 

217-7................... rock 

231-1 

231-2 

231-3 

231-4 

.46 . . . . . . . red-yellow 

.87 . . . . . . . yellow-brown 

1.20 . . . . . . . red-brown 

1.55 . . . . . . . red-brown 

231-5. . . . . . . . 2.01 . . . . . . . red-brown 

231-6. . . . . . . . 2.32 . . . . . . . red-brown 

231-7........ 2.62 ....... red-brown 

231-8. . . . . . . . 2.93 . . . . . . . red-brown 

231-9. . . . . . . . 3.23 . . . . . . . yellow-brown 

231-10 3.54 . . . . . . . yellow-brown 

231-11 . . . . . . 3.84 ....... yellow-brown 

231-12 . . . . . . 4.15 . . . . . . . yellow-brown 

231-13. . . . . . . 4.45 . . . . . . . yellow-brown 

11 

13 

13 

15 

9.5 

6.5 

7.0 

7.5 

15 

15 

11 

6.5 

6.5 

6.0 

5.0 

10 

11 

6.0 

5.0 

6.5 

7.5 

16 

15 

19 

11 

12 

40 

44 

55 

43 

47 

5.0 

7.0 

6.5 

9.5 

5.5 

6.0 

9.0 

43 

12 

8.5 

8.5 

7.5 

8.5 

7.0 

8.0 

8.0 

6.0 

6.5 

.0 

E4 Contributions to Commodity Geology Research 

0.0 

8.0 

17 

16 

42 

62 

46 

54 

4.0 

4.0 

4.0 

2.5 

2.5 

3.5 

8.0 

10 

46 

75 

65 

72 

.0 

1.5 

2.5 

.0 

3.0 

.0 

7.5 

5.0 

2.5 

3.5 

4.0 

4.0 

4.5 

42 

59 

58 

100 

43 

4.0 

20 

10 

11 

20 

3.0 

81 

86 

6.0 

5.0 

8.0 

4.0 

12 

10 

8.0 

8.0 

7.0 

6.0 

6.0 

5.0 

11.5 

12.5 

12.5 

12.5 

11.5 

8.0 

6.0 

14 

10 

11 

3.5 

4.5 

4.0 

10 

10 

10 

11 

14 

14 

14 

16 

10 

12 

12 

12 

12 

6.0 

5.0 

6.0 

9.0 

12 

11 

10 

12 

10 

12 

10 

9.5 

10 

12 

12 

9.5 

2.0 

1.5 

2.0 

8.0 

8.0 

10 

8.5 

9.0 

1.0 

1.0 

5.0 

8.0 

7.5 

14 

13 

7.0 

11 

8 

10 

7.0 

7.0 

2.5 

2.5 

2.5 

.0 

.0 

3.0 

6.0 

6.0 

3.5 

1.5 

6.0 

6.0 

13 

11 

12 

13 

2.0 

.0 

3.0 

.0 

.0 

.0 

1.0 

3.5 

3.5 

.0 

2.0 

2.5 

2.5 

11 

13 

8.5 

3 

3 

2 

4 

5 

4 

3 

2 

23 

22.5 

23 

15 

10.5 

7.5 

4.0 

3.5 

4.5 

5.0 

10 

3.0 

11 

13 

16 

16 

13 

11 

12 

12 

10 

10 

7.5 

0.0 

.0 

3.0 

3.0 

3.5 

5.0 

2.5 

5.0 

.0 

1.5 

3.5 

5.0 

4.0 

7.5 

7.5 

.0 

.0 

4.0 

5.0 

2.5 

2.0 

4.0 

5.0 

5.0 

6.0 

8.0 

.0 

.0 

5.5 

5.0 

5.0 

2.5 

4.5 

3.5 

5.0 

2.0 

2.0 

2.0 

2.5 

2.5 

2.0 

.0 

.0 

.0 

4.0 

4.5 

.0 

.0 

.0 

.0 

6.0 

6.0 

7.5 

9.5 

8.0 

70 

75 

82 

57 

65 

4.0 

3.5 

3.0 

1.5 

1.5 

.0 

.0 

3.0 

3.5 

2.5 

.0 

.0 

.0 

.0 

11 

10 

4.0 

.0 

4.5 

3.0 

2.5 

2.0 

4.5 

5.5 

7.0 

7.5 

9 

10 

7 

11 
and were determined by flame atomic absorption (M. Doughten, analyst). Major oxides are in weight percent and were determined by X-ray spectroscopy 

mineral abundance and are proportional to X-ray peak height as discussed in the text. LOI, loss on ignition; <, less than; IS, insufficient sample] 

Ni (ppm) Co (ppm) Cu (ppm) 

6800 1000 130 

8300 1600 95 

8800 1300 77 

8300 1100 80 

8000 940 82 

8600 830 80 

8800 800 72 

9700 660 52 

2500 130 28 

4900 700 130 

4900 700 110 

5200 640 130 

5700 1100 120 

6200 1100 120 

6000 7fJJ 110 

7500 570 75 

3800 140 10 

4800 440 40 

5200 540 37 

6800 390 23 

6300 3fJJ 23 

5400 370 25 

5000 340 23 

4700 1fJJ 10 

1100 190 120 

1100 180 120 

1100 180 120 

1200 140 100 

1300 lfJJ 90 

260 56 10 

5700 530 110 

5600 620 120 

5900 540 120 

6400 530 80 

6500 440 100 

3000 140 44 

8400 710 100 

7000 630 85 

6900 460 60 

7000 330 60 

6400 330 60 

5900 320 230 

6800 120 12 

3700 450 75 

4500 600 92 

4600 450 82 

4000 450 85 

3500 380 87 

3400 310 82 

3700 300 85 

3400 350 (:jJ 

3200 460 62 

3800 300 82 

4000 290 75 

4400 260 75 

4200 260 72 

Si02 

(wt. %) 

15.1 

20.8 

27.1 

25.5 

27.2 

27.9 

26.6 

29.2 

40.4 

14.7 

18.6 

14.4 

15.3 

18.4 

24.0 

27.8 

40.3 

16.6 

17.8 

26.8 

28.8 

26.3 

28.3 

38.7 

21.2 

22.4 

24.1 

25.0 

22.3 

42.4 

27.1 

25.0 

30.5 

32.2 

34.2 

38.9 

8.6 

16.8 

30.0 

34.7 

34.7 

35.3 

38.9 

17.1 

14.7 

16.2 

17.2 

15.5 

16.0 

15.6 

17.5 

16.9 

13.8 

12.9 

13.0 

11.8 

14.2 

9.0 

8.1 

9.3 

6.9 

4.9 

5.0 

4.4 

2.1 

12.6 

12.8 

10.0 

7.9 

6.6 

7.2 

4.5 

.8 

8.7 

6.7 

4.5 

3.9 

5.3 

4.9 

.4 

23.0 

22.8 

23.1 

22.5 

21.6 

16.3 

5.4 

5.0 

5.0 

3.7 

4.4 

1.2 

6.5 

5.9 

3.1 

2.0 

1.8 

1.7 

.6 

12.7 

13.0 

14.2 

14.5 

13.6 

15.2 

15.1 

13.8 

13.3 

13.9 

13.9 

13.8 

12.9 

41.0 

37.6 

30.8 

33.2 

29.9 

30.5 

33.0 

29.7 

8.4 

48.3 

43.9 

54.1 

53.7 

51.6 

43.9 

37.8 

8.6 

51.7 

51.7 

36.0 

31.6 

35.8 

32.5 

8.8 

33.2 

33.0 

31.6 

29.7 

33.2 

9.1 

34.9 

38.2 

33.6 

31.1 

29.1 

9.8 

58.0 

52.9 

30.5 

21.9 

20.1 

18.6 

8.5 

47.1 

52.6 

50.5 

49.4 

47.9 

50.1 

50.4 

47.9 

48.4 

53.4 

53.3 

53.1 

56.1 

MgO 

(wt. %) 

10.1 

12.9 

15.3 

12.3 

17.3 

18.4 

17.2 

18.5 

37.1 

4.8 

5.0 

3.2 

5.0 

3.0 

4.3 

9.2 

37.7 

4.8 

6.3 

15.8 

17.9 

14.7 

16.5 

36.8 

2.2 

1.8 

2.4 

2.8 

3.2 

8.5 

11.8 

11.9 

12.4 

14.5 

14.7 

36.9 

3.4 

3.1 

19.2 

24.0 

27.6 

29.7 

35.6 

4.5 

2.6 

1.9 

1.9 

3.8 

1.8 

1.5 

4.2 

4.3 

1.8 

2.1 

1.7 

1.6 

CaO 

(wt. %) 

0.16 

.55 

.37 

3.17 

1.13 

.70 

.55 

.65 

2.08 

.28 

.37 

.27 

.40 

.31 

1.01 

.83 

.43 

1.11 

.90 

.59 

.54 

.86 

.81 

.07 

.26 

.19 

.35 

.37 

.61 

16.50 

1.23 

1.27 

1.15 

.90 

1.50 

.59 

.74 

1.97 

1.10 

2.00 

1.15 

.57 

.12 

.08 

<.02 

<.02 

.03 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02 

<0.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

.4 

.3 

.3 

.4 

<.2 

.3 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<0.02 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02. 

<.02 

.11 

.15 

.13 

.07 

.05 

.05 

.03 

<.02 

.09 

.06 

.05 

.04 

.06 

.07 

<.02 

.26 

.27 

.31 

.18 

.15 

.03 

.07 

.06 

.07 

.04 

.05 

<.02 

.03 

.03 

<.02 

<.02 

<.02 

<.02 

<.02 

.13 

.15 

.17 

.20 

.09 

.20 

.19 

.17 

.16 

.15 

.12 

.13 

.11 

Ti02 

(wt. %) 

0.28 

.11 

.06 

.22 

.11 

.08 

.09 

.08 

.03 

.48 

.64 

.32 

.21 

.14 

.20 

.09 

<.02 

.40 

.29 

.19 

.16 

.24 

.23 

<.02 

.90 

1.01 

1.02 

.89 

.79 

.88 

.25 

.23 

.20 

.14 

.26 

<.02 

.11 

.10 

.04 

<.02 

<.02 

<.02 

<.02 

.66 

.51 

.65 

.69 

.52 

.68 

.67 

.62 

.60 

.61 

.57 

.53 

.49 

<0.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

.I 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

.1 

.I 

.I 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

.1 

<.1 

.1 

.I 

<.1 

.1 

.I 

<.1 

<.1 

.I 

.1 

<.1 

<.1 

MnO 

(wt. %) 

0.42 

.58 

.33 

.38 

.35 

.37 

.43 

.37 

.17 

.60 

.64 

.44 

.10 

1.07 

.90 

.92 

.16 

.35 

.41 

.42 

.41 

.44 

.41 

.20 

.28 

.28 

.24 

.01 

.11 

.16 

.51 

.43 

.39 

.38 

.33 

.14 

1.42 

.64 

.44 

.29 

.27 

.23 

.14 

.56 

.37 

.36 

.37 

.42 

.39 

.35 

.37 

.38 

.37 

.36 

.33 

.35 

LOI 

(wt. %) 

13.76 

13.61 

14.11 

12.72 

13.88 

13.82 

13.38 

13.99 

9.19 

11.40 

12.28 

12.15 

11.94 

14.29 

14.99 

15.02 

10.86 

13.69 

12.88 

13.36 

15.20 

14.10 

14.21 

13.62 

16.52 

15.71 

14.84 

15.14 

15.46 

4.64 

11.30 

8.32 

10.59 

11.46 

10.84 

11.02 

15.08 

13.76 

13.22 

12.30 

12.39 

12.41 

13.92 

13.20 

10.99 

11.20 

10.75 

13.49 

11.18 

11.51 

ll.41 

11.10 

10.34 

11.68 

11.60 

10.79 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites E5 
Table 1. Analysis from 11 laterites-Continued 

Site/Sample 

number 

Sample 

depth (m) Sample type 

Ortho- Chlorite Serpentine Goethite Maghemite Quartz Smectite Talc 

pyroxene 

231-14. . . . . . . 4.76 . . . . . . . yellow-brown 

231-15. . . . . . . 5.06 . . . . . . . yellow-brown 

231-16....... 5.37 . . . . . . . yellow-brown 

231-17 . . . . . . 5.67 . . . . . . . yellow-brown 

231-18....... 5.98 . . . . . . . yellow-brown 

231-19 ....... 6.28 . . . . . . . yellow-brown 

231-20. . . . . . . 6.59 . . . . . . . yellow-brown 

232-1. . . . . . . . .31. . . . . . . red-brown 

232-2. . . . . . . . .61 . . . . . . . red-brown 

232-3 . . . . . . . 1.22 . . . . . . . red-brown 

232-4 . . . . . . . 1.53 . . . . . . . red-brown 

232-5. . . . . . . . 1.83 . . . . . . . red-yellow 

232-6 . . . . . . . 2.14....... red-yellow 

232-7 . . . . . . . 2.44 . . . . . . . red-yellow 

232-8. . . . . . . . 2.75 . . . . . . . red-yellow 

232-9. . . . . . . . 3.05 . . . . . . . red-yellow 

232-10 

232-11 

232-12 

232-13 

232-14 

3.36 . . . . . . . red-yellow 

3.66 . . . . . . . red-yellow 

3.97 . . . . . . . red-yellow 

4.27 . . . . . . . red-yellow 

4.58 . . . . . . . red-yellow 

233-1 . . . . . . . .31 . . . . . . . red-brown 

233-2 ....... . 

233-3 

233-4 

233-5 

233-6 

233-7 

.61 . . . . . . . red-brown 

1.22 . . . . . . . red-brown 

1.53 . . . . . . . yellow-brown 

1.83 . . . . . . . yellow-brown 

2.14 . . . . . . . yellow-brown 

2.44 . . . . . . . yellow-brown 

233-8. . . . . . . . 2. 75 . . . . . . . yellow-brown 

233-9. . . . . . . . 3.05 . . . . . . . yellow-brown 

233-10....... 3.36 . . . . . . . yellow-brown 

233-11 . . . . . . 3.66 . . . . . . . yellow-brown 

233-12 . . . . . . 3.97 . . . . . . . yellow-brown 

233-13 . . . . . . . . . . . . . . . . . . rock 

259-1. . . . . . . . .15 . . . . . . . red-brown 

259-2 .31 . . . . . . . red-brown 

259-3 . . . . . . . .61 . . . . . . . yellow-red 

259-4 . . . . . . . .92 . . . . . . . yellow-red 

259-5. . . . . . . . 1.22 . . . . . . . yellow-brown 

259-6. . . . . . . . 1.53 . . . . . . . yellow-brown 

259-7 

259-8 

259-9 

1.83 . . . . . . . yellow-brown 

2.14 . . . . . . . yellow-brown 

rock 

261-1........ .15 ....... red-brown 

261-2 . . . . . . . .31 . . . . . . . red-brown 

261-3. . . . . . . . .61 . . . . . . . red-brown 

261-4 . . . . . . . .92 . . . . . . . gray-brown 

261-5. . . . . . . . 1.22 . . . . . . . gray-brown 

261-6. . . . . . . . 1.53 . . . . . . . yellow-brown 

261-7........ 1.83 . . . . . . . yellow-brown 

261-8........ 2.14 . . . . . . . yellow-brown 

261-9. . . . . . . . 2.44 . . . . . . . yellow-brown 

261-10 . . . . . . . . . . . . . . . . . . rock 

4.5 

7.5 

9.0 

4.5 

1.5 

6.5 

5.5 

6.0 

6.5 

5.0 

7.0 

4.5 

2.0 

2.5 

5.0 

3.5 

2.5 

2.5 

5.5 

7.5 

4.0 

.0 

.0 

5.0 

7.0 

12 

16 

9.0 

5.0 

4.5 

4.0 

7.5 

2.5 

25 

16 

12 

9.0 

10.5 

8.0 

6.0 

6.0 

.0 

.0 

3.5 

2.0 

3.0 

8.0 

6.5 

3.0 

2.0 

E6 Contributions to Commodity Geology Research 

0.0 

.0 

.0 

.0 

.0 

.0 

.0 

.0 

1.5 

.5 

1.5 

.0 

.0 

.5 

.0 

.0 

.0 

.0 

.0 

1.5 

.0 

.0 

.0 

.0 

7.0 

30 

40 

50 

33 

20 

15 

20 

10 

.0 

8.5 

47.5 

100 

100 

100 

100 

100 

25 

20 

18 

100 

.0 

.0 

.0 

.0 

.0 

10 

11 

11 

12 

13 

14 

13 

12 

11 

12 

11 

13 

18 

8.0 

13 

15 

14 

12 

12 

11 

12 

22 

20 

18 

16 

15 

14 

13 

16 

13 

13 

9.5 

14 

11 

16 

13 

10 

10 

9 

8 

8 

13 

14 

13 

13 

13 

13 

12 

14 

11 

4.5 

5.0 

4.0 

7.0 

8.5 

8.0 

7.5 

3.0 

4.0 

2.0 

2.5 

.0 

.0 

4.5 

1.5 

3.5 

18 

7.0 

2.5 

3.0 

1.5 

3.0 

2.0 

2.0 

2.0 

2.0 

4.0 

8.5 

4.0 

3.0 

5.5 

10.5 

6.5 

7.0 

3.0 

5.0 

6.0 

7.0 

7.0 

7.0 

9.0 

9.0 

9.0 

11 

11 

9.5 

11 

9.0 

13 

14 

8.5 

9.0 

8.5 

8.0 

2.0 

4.0 

2.5 

16 

15 

16 

18 

13 

10 

10 

12 

5.0 

2.0 

4.0 

15 

14 

11 

8.0 

5.0 

4.0 

4.5 

2.0 

2.0 

2.0 

1.0 

.0 

.0 

.0 

.0 

.0 

.0 

2.0 

.0 

.0 

.0 

.0 

.0 

7.0 

6.0 

7.5 

3.0 

8.0 

5.5 

5.5 

5.0 

3.5 

.0 

3.5 

6.5 

6.0 

5.5 

4.5 

9.5 

13 

12 

13 

13 

3.5 

5.5 

3.5 

1.5 

1.5 

3.0 

5.5 

5.5 

5.0 

5.5 

5.0 

11 

15 

6.5 

.0 

.0 

.0 

.0 

5.5 

1.5 

3.0 

3.0 

2.5 

11 

.0 

.0 

.0 

.0 

.0 

.0 

.0 

2.0 

1.0 

4.0 

9.5 

Tremolite Hornblende 

2.0 

3.0 

4.0 

1.5 

3.0 

1.5 

2.5 

1.5 

1.5 

.0 

2.0 

4.0 

1.5 

2.0 

.0 

.0 

.0 

.0 

2.5 

3.0 

3.0 

2.0 

3.0 

1.5 

2.5 

2.5 

10 

2.0 

5.0 

4.0 

5.0 

1.0 

4.0 

6.0 

.0 

.0 

.0 

.0 

.0 

.0 

2.0 

1.0 

2.0 
Ni (ppm) Co (ppm) Cu (ppm) 

5200 340 55 

5000 480 57 

5400 470 60 

6300 660 62 

6100 860 67 

5700 2000 77 

5700 1500 97 

5300 720 70 

5200 700 70 

5800 720 70 

3900 510 87 

5700 910 80 

5500 600 63 

6100 1000 70 

6100 570 63 

7900 630 85 

6200 480 110 

6400 660 80 

5800 760 67 

5800 720 65 

7000 1000 72 

7300 630 70 

7200 760 70 

7000 1200 57 

9200 1300 57 

13000 700 63 

13000 1000 53 

11000 1000 71 

14000 880 43 

14000 920 68 

5500 440 97 

16000 1100 98 

15000 840 63 

6200 110 14 

4300 400 72 

5900 410 120 

5400 430 95 

4800 430 72 

5000 300 60 

4300 260 45 

4400 250 35 

5000 250 20 

2100 100 10 

8100 1200 120 

8800 950 110 

8100 1200 100 

10000 2700 65 

13000 2000 45 

14000 1800 55 

12000 1200 95 

11000 1200 100 

10000 950 70 

2700 170 10 

Si02 

(wt. %) 

13.7 

15.3 

15.1 

10.7 

6.5 

11.6 

14.1 

23.2 

24.0 

23.5 

28.1 

22.1 

10.4 

20.3 

21.6 

9.9 

2.5 

8.4 

23.0 

22.9 

16.1 

5.1 

4.0 

7.4 

10.0 

21.0 

17.4 

11.4 

21.3 

24.2 

IS 

IS 

19.2 

41.2 

23.9 

17.8 

19.4 

24.6 

27.6 

31.6 

33.6 

35.8 

39.4 

3.9 

3.7 

3.2 

3.2 

4.1 

5.7 

7.7 

7.7 

12.1 

40.3 

10.5 

11.6 

10.8 

8.9 

7.8 

9.7 

10.9 

11.2 

11.4 

10.5 

13.2 

10.0 

7.0 

11.3 

11.1 

10.2 

5.2 

6.7 

11.1 

10.9 

9.8 

5.9 

5.3 

5.2 

4.5 

3.2 

3.4 

3.0 

2.9 

3.4 

IS 

IS 

3.0 

.6 

14.2 

13.8 

12.0 

9.9 

8.6 

6.8 

5.4 

4.1 

1.8 

7.7 

8.3 

8.0 

5.0 

4.2 

4.7 

6.4 

6.5 

5.6 

.8 

58.8 

56.6 

57.6 

63.6 

69.4 

62.5 

56.1 

41.4 

41.0 

42.6 

35.7 

44.3 

60.2 

46.4 

45.5 

58.3 

77.6 

68.0 

43.1 

43.4 

51.9 

66.1 

67.8 

65.3 

63.1 

48.2 

52.9 

66.6 

48.5 

44.8 

IS 

IS 

50.3 

9.3 

32.7 

42.1 

40.3 

32.8 

28.6 

23.1 

20.3 

18.6 

8.4 

66.4 

67.4 

70.8 

74.1 

73.0 

68.2 

63.6 

65.9 

58.9 

9.2 

MgO 

(wt. %) 

1.8 

1.7 

1.8 

1.8 

1.8 

2.4 

3.5 

4.7 

4.5 

4.7 

4.7 

4.8 

2.6 

3.3 

3.4 

1.5 

.7 

1.9 

4.1 

4.5 

3.7 

1.7 

1.4 

2.9 

4.0 

10.2 

8.6 

5.2 

10.9 

12.4 

IS 

IS 

9.9 

39.1 

10.2 

6.8 

9.1 

14.7 

18.2 

21.7 

24.7 

26.1 

36.5 

1.1 

.8 

.9 

.9 

1.2 

2.0 

2.7 

2.8 

8.2 

41.5 

CaO 

(wt. %) 

<0.02 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02 

.46 

.47 

.55 

.44 

.55 

.19 

.32 

.31 

.06 

<.02 

.13 

.44 

.46 

.27 

<.02 

<.02 

.12 

.25 

1.07 

.66 

.38 

.88 

.99 

IS 

IS 

.72 

.54 

1.67 

.59 

.83 

.56 

1.20 

.76 

.77 

.64 

.98 

.08 

.04 

<.02 

.03 

.05 

.27 

.72 

.57 

.17 

.71 

<0.02 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

IS 

IS 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

<.2 

0.15 

.22 

.19 

.12 

.05 

.11 

.11 

.21 

.23 

.21 

.30 

.15 

.05 

.15 

.25 

.15 

<.02 

.08 

.20 

.18 

.16 

.03 

<.02 

.03 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02 

IS 

IS 

<.02 

<.02 

.19 

.12 

.09 

.08 

.06 

.04 

<.02 

<.02 

<.02 

.06 

.05 

.04 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02 

<.02 

Ti02 

(wt. %) 

0.38 

.43 

.43 

.28 

.14 

.24 

.25 

.52 

.55 

.50 

.69 

.43 

.17 

.53 

.50 

.28 

.06 

.18 

.53 

.51 

.37 

.11 

.07 

.07 

.04 

.03 

<.02 

<.02 

<.02 

<.02 

IS 

IS 

<.02 

<.02 

.45 

.34 

.29 

.26 

.22 

.16 

.11 

.08 

<.02 

.13 

.13 

.11 

.08 

.07 

.06 

.06 

.05 

<.04 

<.02 

<0.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

.1 

.1 

.1 

.1 

.1 

<.1 

.1 

.1 

.1 

<.1 

<.1 

.1 

.1 

.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

IS 

IS 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

<.1 

MnO 

(wt. %) 

0.39 

.44 

.48 

.51 

.56 

.78 

.83 

.70 

.70 

.65 

.73 

.76 

.36 

.85 

.45 

.28 

.18 

.37 

.63 

.61 

.57 

.39 

.37 

.49 

.65 

.57 

.87 

1.09 

.97 

.78 

IS 

IS 

.90 

.13 

.57 

.39 

.50 

.64 

.40 

.39 

.34 

.34 

.14 

.76 

.66 

.78 

1.44 

1.20 

1.17 

.94 

1.05 

.92 

.21 

LOI 

(wt. %) 

8.22 

9.01 

8.84 

8.09 

7.72 

7.92 

9.45 

11.85 

12.30 

11.51 

11.32 

11.68 

13.65 

11.15 

11.10 

13.54 

8.36 

9.01 

11.16 

10.85 

11.95 

15.59 

15.49 

13.20 

13.05 

11.68 

11.62 

8.60 

10.60 

9.00 

IS 

IS 

11.04 

8.15 

12.46 

13.84 

13.05 

12.69 

11.96 

12.02 

11.64 

10.89 

11.28 

13.91 

13.61 

11.38 

10.65 

10.41 

12.76 

12.28 

11.30 

10.22 

6.48 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites E7 
Table 2. Mineralogical and chemical summary 

Relative change in mineral abundance with increasing sample depth1 

Site Serpentine Chlorite Goethite 

211 ......... Inc Dec Dec 

213 ......... Inc Dec Dec 

214 ......... Inc Dec Dec 

215 ......... NC Dec NC 

216 ......... NC NC NC 

217 ......... Inc NC Dec 

231 ......... Dec Dec NC 

232 ......... Inc NC NC 

233 ......... Inc Inc Dec 

259 ......... Inc Dec Dec 

261 ......... Inc Inc Dec 

Maghemite Smectite Quartz 

Inc Inc 

Inc Inc Dec 

Inc Inc Dec 

Dec Inc Dec 

NC Inc NC 

Inc NC 

Inc Dec 

NC Dec 

Inc 

Inc Dec 

Inc 

Talc 

Dec 

Dec 

Dec 

Dec 

NC 

Dec 

Inc 

Inc 

Hornblende 

Dec 

Inc 

Inc 

NC 

Inc 

NC 

Inc 

Orthopyroxene 

Tremolite 

Dec Dec 

Inc 

Bedrock mineralogy2 

Site Serpentine Chlorite Olivine Ortho- Clino- Maghemite Goethite Talc Horn- Magnetite Tremolite 

pyroxene pyroxene blende 

211 ......... X X X X X 

213 ......... X X X X 

214 ......... X X 

215 ......... X X X X 

216 ......... X X X X X X X 

217 ......... X X X 

233 ......... X X X X 

259 ......... X X X X X 

261 ......... X X X 

Trends in laterite chemistry with increasing depth1 

Site MgO Si02 Fe2 0 3 

211. ........ Inc Inc Dec 

213 ......... Inc Inc Dec 

214 ......... Inc Inc Dec 

215 ......... Inc NC NC 

216 ......... Inc Inc Dec 

217 ......... Inc Inc Dec 

231 ......... NC NC Inc 

232 ......... NC NC NC 

233 ......... Inc Inc Dec 

259 ......... Inc Inc Dec 

261 ......... Inc Inc Dec 

1

Inc, increase; Dec, decrease; NC, no change. 2

x indicates presence of mineral. 

Al2 0 3 Ti02 

Dec Dec 

Dec Dec 

Dec Dec 

NC NC 

Dec Dec 

Dec Dec 

Dec Dec 

NC NC 

Dec Dec 

Dec Dec 

Dec Dec 

The abundance of a mineral in these samples is, in 

part, reflected by the intensity of its X-ray diffraction peaks. 

Peak intensity is, however, also dependent on other factors, 

such as degree of crystallinity, orientation, and interferences. As a result, obtaining quantitative mineral modes 

from diffraction data is an extremely difficult task (Grim, 

1968) and was not done for these samples. An attempt was 

made, however, to qualitatively estimate mineral abundances within each of the 11 laterite profiles. These 

estimates were made by measuring the height above background of each mineral's most intense reflection. Mineral 

abundance estimates derived from X-ray diffraction data 

most often are made by measuring the area under peaks. 

Although less accurate, measurement of peak height has 

also been shown to be closely related to mineral abundance 

(Gibbs, 1965). 

E8 Contributions to Commodity Geology Research 

CaO Ni Co MnO Cu 

Inc Inc Dec NC Dec 

Inc Inc Inc Inc Dec 

NC NC Dec Inc Dec 

Inc Inc Dec Dec Dec 

NC Inc Dec Dec Dec 

NC Dec Dec Dec Dec 

NC Inc Inc Inc NC 

NC Inc NC NC NC 

Inc Inc NC Inc NC 

NC NC Dec Dec Dec 

Inc Inc NC Inc Dec 

The mineralogical and chemical data for the 11 

profiles are presented in table 1 and are partly summarized 

in tables 2 and 3. The X-ray traces and plots of mineralogical and chemical data from two profiles (sites 216 and 233) 

are given in figures 2 and 3 as further illustration of the 

approach used in this study. 

LATERITE MINERALOGY 

The mineralogy of these laterite profiles is relatively 

simple (table 2). All contain serpentine, chlorite, goethite, 

and maghemite. Additional phases that are present in some 

samples, but not all, are smectite, quartz, talc, and hornblende. No attempt was made to further identify the 

smectite, but on the basis of the iron-rich composition of 
Table 3. Range of laterite compositions 

[Mean values are computed on untransformed data (arithmetic (Ar.) means) and on log-transformed data (geometric (Gm.) means). Sd., standard 

deviations. Numbers in parentheses indicate number of samples analyzed] 

Site 

211 

(8) 

213 

(7) 

214 

(6) 

215 

(5) 

216 

(5) 

217 

(6) 

231 

(20) 

232 

(14) 

233 

(10)* 

259 

(8) 

Min. 

Max. 

Ar. mean 

Sd. 

Gm. mean 

Sd. 

Min. 

Max. 

Ar. mean 

Sd. 

Gm. mean 

Sd. 

Min. 

Max. 

Ar. mean 

Sd. 

Gm. mean 

Sd. 

Min. 

Max. 

Ar. mean 

Sd. 

Gm. mean 

Sd. 

Min. 

Max. 

Ar. mean 

Sd. 

Gm. mean 

Sd. 

Min. 

Max. 

Ar. mean 

Sd. 

Gm. mean 

Sd. 

Min. 

Max. 

Ar. mean 

Sd. 

Gm. mean 

Sd. 

Min. 

Max. 

Ar. mean 

Sd. 

Gm. mean 

Sd. 

Min. 

Max. 

Ar. mean 

Sd. 

Gm. mean 

Sd. 

Min. 

Max. 

Ni (ppm) 

6,800 

9,700 

8,413 

827 

8,375 

1.1074 

4,900 

7,500 

5,771 

920 

5,712 

1.1644 

4,800 

6,800 

5,583 

791 

5,539 

1.1471 

1,100 

1,300 

1,160 

89 

1,157 

1.0780 

5,600 

6,500 

6,020 

409 

6,009 

1.0698 

5,900 

8,400 

6,933 

838 

6,893 

1.1249 

3,200 

6,300 

4,490 

966 

4,394 

1.2351 

3,900 

7,900 

5,907 

908 

5,840 

1.1727 

5,500 

16,000 

11,017 

3626 

10,414 

1.4355 

4,300 

5,900 

Co (ppm) 

660 

1,600 

1,029 

303 

993 

1.327 

570 

1,100 

796 

216 

773 

1.294 

340 

540 

407 

74 

402 

1.184 

140 

190 

170 

20 

169 

1.130 

440 

620 

532 

64 

529 

1.130 

320 

710 

463 

170 

439 

1.425 

260 

2,000 

559 

441 

467 

1.732 

480 

1,000 

713 

163 

696 

1.252 

440 

1,300 

898 

245 

864 

1.351 

250 

430 

Si02 (percent) 

15.1 

29.2 

24.9 

4.7 

24.5 

1.25 

14.4 

27.8 

19.0 

5.1 

18.5 

1.29 

16.6 

28.8 

24.1 

5.4 

23.5 

1.28 

21.2 

25.0 

23.0 

1.5 

23.0 

1.07 

25.0 

34.2 

29.8 

3.7 

29.6 

1.14 

8.6 

35.3 

26.7 

11.3 

23.8 

1.78 

6.5 

17.5 

14.3 

2.7 

14.0 

1.25 

2.5 

28.1 

18.3 

7.5 

15.9 

1.92 

4.0 

24.2 

11.7 

7.4 

12.0 

1.9 

17.8 

35.8 

MgO (percent) 

10.1 

18.5 

15.3 

3.1 

14.9 

1.25 

3.0 

9.2 

4.9 

2.0 

4.6 

1.44 

4.8 

17.9 

12.7 

5.6 

11.3 

1.77 

1.8 

3.2 

2.5 

.5 

2.4 

1.25 

11.8 

14.7 

13.1 

1.4 

13.0 

1.11 

3.1 

29.7 

17.8 

11.8 

12.6 

2.89 

1.5 

4.5 

2.4 

2.3 

1.45 

.7 

4.8 

3.5 

1.3 

3.1 

1.74 

1.4 

12.4 

6.7 

4.1 

5.3 

2.23 

6.8 

26.1 

29.7 

41.0 

33.2 

4.1 

33.0 

1.12 

37.8 

54.1 

47.6 

6 

47.3 

1.14 

31.6 

51.7 

39.9 

9.3 

39.0 

1.25 

29.7 

33.2 

32.1 

1.5 

32.1 

1.05 

29.1 

38.2 

33.4 

3.5 

33.2 

1.11 

18.6 

58.0 

33.7 

17.4 

30.2 

1.65 

47.1 

69.4 

54.2 

5.9 

54.0 

1.11 

35.7 

77.6 

50.0 

11.9 

48.8 

1.25 

44.8 

67.8 

57.4 

9.2 

56.7 

1.18 

18.6 

42.1 

4.4 

14.2 

7.7 

3.2 

7.2 

1.49 

4.5 

12.8 

8.8 

3.1 

8.3 

1.46 

3.9 

8.7 

5.7 

1.8 

5.5 

1.34 

21.6 

23.1 

22.6 

.6 

22.6 

1.03 

3.7 

5.4 

4.7 

.7 

4.7 

1.16 

1.7 

6.5 

3.5 

2.2 

3.0 

1.83 

7.8 

15.2 

12.5 

2.1 

12.3 

1.20 

5.2 

13.2 

10.0 

2.2 

9.7 

1.30 

2.9 

5.9 

4.0 

1.1 

3.8 

1.31 

4.1 

14.2 

MnO (percent) 

0.33 

.58 

.40 

.08 

.40 

1.19 

.10 

1.07 

.67 

.33 

.55 

2.25 

.35 

.44 

.41 

.03 

.41 

1.08 

.01 

.28 

.18 

.12 

.12 

4.15 

.33 

.51 

.41 

.07 

.40 

1.18 

.23 

1.42 

.55 

.45 

.44 

1.98 

.33 

.83 

.45 

.14 

.43 

1.30 

.18 

.85 

.56 

.20 

.52 

1.56 

.37 

1.09 

.71 

.25 

.66 

1.47 

.34 

.64 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites E9 
Table 3. Range of laterite compositions-Continued 

[Mean values are computed on untransformed data (arithmetric (Ar.) means) and on log-transformed data (geometric (Gm.) means). Sd., standard 

deviations. Numbers in parentheses indicate number of samples analyzed] 

Site Ni (ppm) Co (ppm) Si02 (percent) MgO (percent) Fe2 0 3 (percent) Al20 3 (percent) MnO (percent) 

Ar. mean 4,888 341 26.8 16.4 29.8 9.3 .45 

Sd. 567 84 6.5 7.4 8.8 3.8 .11 

Gm. mean 4,860 332 26.1 14.8 28.6 8.6 .44 

Sd. 1.1202 1.286 1.29 1.65 1.36 1.57 1.27 

261 Min. 8,100 950 3.2 .8 58.9 4.2 .66 

(9) Max. 14,000 2,700 12.1 8.2 74.1 8.3 1.44 

Ar. mean 10,556 1,467 5.7 2.3 67.6 6.2 .99 

Sd. 2118 585 3 2.4 4.7 1.5 .25 

Gm. mean 10,371 1,380 5.1 1.7 67.4 6.1 .96 

Sd. 1.2204 1.428 1.6 2.15 1.07 1.28 1.28 

All Min. 1,100 140 2.5 .7 18.6 1.7 .01 

profiles Max. 16,000 2,700 35.8 29.7 77.6 23.1 1.44 

(98)** Ar. mean 6,575 704 18.5 7.3 45.7 8.8 .53 

Sd. 3032 439 8.6 7.1 14.2 4.9 .27 

Gm. mean 5,864 593 16.3 4.8 44.3 7.7 .47 

Sd. 1.6800 1.813 1.84 2.61 1.40 1.78 1.86 

All Min. 3,200 250 2.5 .7 18.6 1.7 .10 

profiles Max. 16,000 2,700 35.8 29.7 77.6 15.2 1.44 

except 215 Ar. mean 6,860 732 18.3 7.6 46.4 8.0 .55 

(93)*** Sd. 2835 433 8.7 7.1 14.2 3.8 .27 

Gm. mean 6,387 633 16.0 5.0 45.1 7.2 .51 

Sd. 1.4454 1.704 1.86 2.64 1.40 1.70 1.58 

*Data for Ni and Co based on 12 samples; all other data are from 10 samples. 

** Data for Ni and Co based on 100 samples; all other data are from 98 samples. 

*** Data for Ni and Co based on 95 samples; all other data are from 93 samples. 

these laterites and the yellow-green color of some clay-rich 

samples, it is reasonable to assume that they are nontronitic. 

Only two profiles contain orthopyroxene, and only one has 

small amounts of tremolite. 

The bedrock mineralogy is also simple and consists 

predominantly of serpentine, with lesser amounts of chlorite, olivine, and maghemite. Additionally, clino- and 

orthopyroxene, talc, goethite, hornblende, tremolite, and 

magnetite occur in some samples. The bedrock at site 215, 

however, differs markedly in composition from the other 

rock samples as it is composed predominantly of hornblende, chlorite, talc, and goethite and contains little or no 

serpentine. 

There are three mineralogical associations that are 

worth noting. First, all soil profiles that contain hornblende 

also have talc. Although talc typically is derived from the 

weathering of pyroxenes (Boeglin and others, 1983), the 

association noted here may indicate that in these samples 

some talc results from the alteration of hornblende. Second, 

tremolite occurs only in one of the two samples containing 

orthopyroxene, perhaps indicating that it is an alteration of 

orthopyroxene. Third, samples having smectite occur only 

in the northern part of the area sampled, within the 

boundaries of the Kalmiopsis Wilderness (fig. 1). A possible explanation for this distribution is presented later. 

El 0 Contributions to Commodity Geology Research 

Within most profiles, mineralogy changes systematically. In general, serpentine, maghemite, smectite, and 

hornblende increase with depth. Conversely, goethite, chlorite, talc, and quartz are usually most abundant toward the 

surface. Notable exceptions to these trends occur in samples 

from sites 215, 216, 231, and 232 (table 2). 

As previously mentioned, the profile at site 215 

formed over a hornblende-rich bedrock that is compositionally distinct from the serpentine-rich rocks associated with 

the base of the other profiles. As a result, little serpentine is 

present in the profile from site 215, and evidently most of 

the other mineralogical trends present in the other profiles 

also did not develop. The samples from site 215 are also 

markedly lower in nickel than those which formed over 

ultramafic bedrock (1,100-1,300 ppm vs. 3,200-16,000 

ppm). 

The profiles from sites 216,231, and 232, which also 

do not show the systematic mineralogical trends of the other 

profiles, have been slumped and mixed. Sites 216 and 232 

both are in landslide masses and have evidently been so 

completely homogenized that any initial vertical change in 

mineralogy has been eliminated. The profile for site 231 is 

also from a landslide but has apparently retained some 

component of its original profile. Increases in serpentine 

and maghemite and decreases in goethite and chlorite are 

observed to a depth of about 3.2 m, but below this depth 
A Cl 

550°C 

T 350°C Cl 

T 216-1 

EG 

CltT 

Cl CltSm A 

216-1 

550°C 

350°C 

216-3 

EG 

216-2 A 

I->- ~ U5 216-3 U5 550°C z z w w I- I-

~ ~ 350°C 

216-5 

EG 

A 

216-4 

216-5 

s 

CltS 

I 216-

bedrock 

Cl Cl Cl 

60 50 40 30 20 

2 THETA 

Figure 2. X-ray mineralogy and chemistry for profile from 

site 216. A, Hand-smoothed X-ray diffraction patterns. 

(Abbreviations: Cl, chlorite; S, serpentine; G, goethite; 

Mh, maghemite; Q, quartz; Sm, smectite; T, talc; 01, 

olivine; Hb, hornblende.) B, Diffraction patterns of samples settled from water onto porcelain tiles and then dried 

10 

216-

bedrock 

0 

A 

I I I I I I I I I 

16 14 12 10 8 6 4 2 0 

2 THETA 

in air (A), treated with ethylene glycol (EG), heated to 350 

oc, and heated to 550 oc. C, Qualitative vertical variations 

in mineral abundances. D, Vertical variations in profile 

chemistry. £, Net change in Ni, Co, Si02 , Fe20 3 , MgO, 

and MnO calculated assuming Al20 3 is constant. Method 

of calculation discussed in text. 
c D 

U) 

a: U) 

w 

1-- a: 

w w 

~ 1--

0.6 w 

z ~ 

I~ 

z 

1-- :i" 

a.. 

w 1--

a.. 

0 w 

0 

0.8 0.8 

1.2 

10 20 30 40 50 60 70 80 90 2 4 6 8 10 12 14 16 

QUALITATIVE MINERAL ABUNDANCE AMOUNT OF ELEMENT/OXIDE 

EXPLANATION EXPLANATION 

D Chlorite + Serpentine 0 Goethite D NiX 10 (WT%) +Cox 100 (WT%) ~ Si0/10 (WT%) 

• Smectite v Quartz X Talc X Fep/10 (WT%) vMgO(WT%) • A1p 3(WT%) 

~ Maghemite EB Hornblende EB Ti02 x 10 (WT%) ® Cu/10 (ppm) 0 MnO x 10 (WT%) 

Figure 2. Continued. + CaO x 10 (WT%) 

Figure 2. Continued. 

E12 Contributions to Commodity Geology Research 
C/) 

a: 

w 

1-

w 

~ 

z 

I 

1-

0... 

w 

Cl 

E 

0.1 

0.3 

0.5 

0.7 

0.9 

1.1 

1.3 

-100 -50 

PERCENT CHANGE 

EXPLANATION 

0 

D Ni + Co D. Si02 

X Fep3 v MgO 0 MnO 

Figure 2. Continued. 

there is little discernible change in relative mineral abundances. The abrupt change at 3.2 m occurs where two 

profiles have been juxtaposed; the upper part has the 

mineral zonation typical of most of the other profiles and 

has apparently moved over a material that either had been 

previously homogenized or over a material in which there 

was relatively little mineralogical variation. 

CHEMICAL VARIATIONS 

Data for Si02 , Fe20 3 , and Al20 3 most closely 

approximate normal distributions and, therefore, may best 

be characterized by arithmetic means. Data for Ni, Co, 

MgO, and MnO, however, approximate lognormal distributions, and for these elements the geometric mean (average value of the log-transformed data) provides a better 

measure of the central tendency of these data. Table 3 gives 

the arithmetic and geometric means, the maximum and 

minimum values, and standard deviations of these elements. 

With the exception of samples from site 215, geometric means of Ni and Co are 6,387 ppm and 633 ppm 

(range of means are 4,394 to 10,414 ppm for Ni and 332 to 

1,380 ppm for Co). Abundance of Si02 (arithmetic mean of 

18. 3; range of 5. 7 to 29. 8 percent) and MgO (geometric 

mean of 5.0; range of 1.7 to 14.9 percent) is directly 

related to mineralogy, the greatest amounts occurring in 

profiles that have the largest relative amounts of serpentine 

(or talc, in the case of profile 216). Similarly, abundance of 

Fe20 3 (arithmetic mean 46.4, range of 29.8 to 67.6 percent) 

increases as the amount of goethite increases. 

The range in composition of these laterites agrees 

with those reported in a survey of laterites occurring in this 

area (Ramp, 1978) and also in specific studies of the Red 

Flats (Libbey and others, 1947; Hundhausen and others, 

1954), Pine Flat, and Diamond Flat (Benson, 1963) deposits. These compositions also fit the category defined by 

Chandra and Ruud (1976) as transitional between high-iron 

nickeliferous limonite deposits and high-silica serpentinous 

ores. Some of these profiles are similar to compositions that 

have been used to test the recovery of nickel and cobalt by 

a variety of hydrometallurgical processes (Siemens and 

others, 1975; Duyvesteyn and others, 1979; Kukura and 

others, 1979). 

Those profiles that have changes in mineralogy also 

show systematic changes in chemistry (table 2). Among 

profiles that are largely undisturbed, there are consistent 

depth-related increases in MgO and Si02 content and 

decreases with depth in Fe20 3 , Al20 3 , and Ti02 content. 

Changes associated with CaO, MnO, and nickel, which 

generally increase with depth, and copper, which generally 

decreases with depth, are less consistent. Cobalt, in contrast, exhibits neither a predictable increase nor decrease 

with depth. Most of these chemical trends are also present 

in the disturbed profile at site 216. However, these trends 

are not found in the other disturbed profiles (231 and 232) 

and appear not to be developed at site 215. 

As expected, many of these oxides show reasonably 

consistent correlations (table 4). Particularly good positive 

correlations are noted between MgO and Si02 , which could 

be expected as both oxides are associated with serpentine 

and increase downward from the leached upper part of the 

laterite profile to the higher concentrations found in the 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites E13 
A 

G 

Mh 

~ U5 

z 

UJ 

I-

~ 

60 50 40 30 20 

2 THETA 

Figure 3. X-ray mineralogy and chemistry for profile from 

site 233. A, Hand-smoothed X-ray diffraction patterns. 

(Abbreviations: Cl, chlorite; S, serpentine; G, goethite; 

Mh, Maghemite; T, talc; 01, olivine; Opx, orthopyroxene.) B, Diffraction patterns of samples settled from water 

onto porcelain tiles and then dried in air (A), treated 

T 

233-1 

233-2 

233-3 

233-4 

233-5 

233-6 

233-7 

233-9 

233-12 

I 

I 

233- I 

bedrock 1 

B 

~ U5 

z 

UJ 

I-

~ 

550°C 

350°C 

EG 

A 

550°C 

350°C 

EG 

A 

550°C 

350°C 

EG 

A 

550°C 

350°C 

EG 

A 

550°C 

350°C 

EG 

A 

550°C 

350°C 

EG 

A 

I I I I I I 

10 0 16 14 12 10 8 6 4 2 0 

I 2 THETA 

233-1 

233-4 

233-5 

233-8 

233-10 

233-12 

233-

bedrock 

with ethylene glycol (EG), heated to 350 oc, and heated to 

550 oc. C, Qualitative vertical variations in mineral 

abundances. D, Vertical variations in profile chemistry. f, 

Net change in Ni, Co, Si02, Fe20 3 , MgO, and MnO 

calculated assuming Al20 3 is constant. Method of 

calculation discussed in the text. 
CJ) 

0::: 

w 

1--

w 

~ 

z 

I 

1--

0... 

w 

0 

c 

2 

QUALITATIVE MINERAL ABUNDANCE 

(RELATED TO X-RAY PEAK HEIGHT) 

EXPLANATION 

0 Chlorite 

6 Maghemite 

EB Hornblende 

+ Serpentine 

X Orthopyroxene 

() Goethite 

v Talc 

Figure 3. Continued. 

D 

CJ) 

0::: 

w 

1--

w 

~ 

z 2 

I 

1--

0... 

w 

0 

3 

2 4 6 8 1 0 12 14 16 18 20 

AMOUNT OF ELEMENT/OXIDE 

EXPLANATION 

0 NiX 10 (WT%) + Cox 100 (WT%) () MnO x 10 (WT%) 

X Fep/10 (WT%) V MgO(WT%) 0 A1p3 (WT%) 

• Ti02 x 10 (WT%) A Cu/10 (ppm) 6 Si0/1 0 (WT%) 

• CaO x 10 (WT%) 

Figure 3. Continued. 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites E15 
(j) 

a: 

w 

1--

w 

~ 

z 2 

I 

1--

c... 

w 

0 

3 

E 

4 ~~~~~~~~--~~~~-L-¥~~--~ 

-100 -50 0 

PERCENT CHANGE 

EXPLANATION 

0 Ni + Co 6 Si02 

X Fep3 v MgO () MnO 

Figure 3. Continued. 

+50 

parent rock. However, the correlations for several of the 

profiles are not as high as expected, and a plot of these data 

reveals at least two different trends (fig. 4). The first of 

these is defined by samples from profiles 213, 215, 231, 

and 232 (dashed line; fig. 4), while samples from the 

remaining profiles define a second curve. 

E16 Contributions to Commodity Geology Research 

DISCUSSION 

The distribution of major oxides appears to follow 

trends predicted by relatively simple models. Golightly 

(1981) shows that the depth-related change in the concentration of an element (x) that is leached during lateritic 

weathering may be modeled by 

where: 

Cx is the concentration of element X in the laterite, 

Cxo is the initial concentration of element x, 

(1) 

Ax is a constant related to the solubility of the element, 

and 

d is the depth. 

Similarly, the relationship between two oxides (x and y) 

may be expressed as: 

or 

(3) 

The solid curve in figure 4 represents the solution to 

equation 3 for bedrock concentrations of Si02 and MgO, 

respectively, of 39 and 37 weight percent. A value of 2 was 

assigned for the constant Ayf Ax and was chosen to produce 

a curve which fit the data. Actual solubility values for Ax 

and AY are not known and in fact will change with different 

weathering conditions. The ratio used here, however, is 

consistent with the observed greater mobility of MgO 

relative to Si02 and also approximates the extreme ends of 

the relative mobility scale given by Trescases (1975) in 

which the mobility of magnesium is given as 1.0, while that 

of silicon ranges between 0.5 and 1.0. 

Similar complexities are observed in the relation 

between MgO and Fe20 3 (fig. 5). Samples from profiles 

213, 215, 231, and 232 again do not lie on the exponential 

curve made by samples from the other profiles. The fitting 

of a theoretically derived curve to the pattern made by these 

data is, however, not as straightforward as in the previous 

case. Both MgO and Si02 are removed during weathering, 

and equation 3 is designed to accommodate the leaching of 

such oxides. Iron, on the other hand, is residually enriched 

in the laterite, and its behavior is, therefore, not directly 

predicted by the leaching model ( eq. 3). 

By making certain assumptions, however, the above 

model may be simplified and redesigned to approximate 

variations in Fe20 3 . First, Fe20 3 and Al20 3 are considered 

to be the only two major oxides not leached from the laterite 

and, therefore, are residually enriched in the upper part of 

the profile. This assumption is supported by the trends 

shown in table 2. Second, because all other oxides are 

removed during weathering, they may be lumped together 

and treated as the "leached component" and modeled by 

equation 1 as: 

C C C -A · d lc = leo- leo • e lc (4) 
Table 4. Correlation of abundance of elements, oxides, and minerals 

[Numbers with asterisk give correlation at the 1-percent confidence level; numbers without asterisk give correlation at the 5-percent confidence level; blanks 

are not significantly correlated at the 5-percent confidence level. Correlations were made by using data that either fit a normal distribution or that were 

transformed to be normally distributed. Values for Si02 , Fe20 3 , Al20 3 , goethite, and serpentine are normally distributed; data for MgO, MnO, Ti02 , Ni, 

and Co are lognormally distributed and were transformed] 

Si02 Log 

vs. MgO Si02 Fe20 3 Fe20 3 Al 20 3 Log Log 

Site vs. vs. vs. log vs. log Co vs. Ni vs. log vs. 

MgO Fe20 3 

Al 20 3 Al 20 3 MnO Ti02 log Ni Si02 

211 ...... 0.89* -0.88* -0.91* 0.84* 0.79 0.86* 

213 ...... -.77 .99* .8 

214 ...... .99* -.98* -.94 .91 * .98* 

215 ...... 

216 ...... .9 -.9 .95* 

217 ...... .96* -.98* -.99* .99* 0.95* .99* -.83 

231 ...... -.45 .72* -.89* .49 .92* .64* -.68* 

232 ...... .93* -.93* .91* -.94* -.89* .95* -.6 

233 ...... .97* -.91* .92* .96* .94* 

259 ...... .97* -.97* -.93* .91* .97* 

261 ...... .99* -.83* .65 

All ....... .84* -.81* .37* .82* .75* -.2 

0 215 bedrock 0 

40 0 

~ --- / 

0 0 I 0 0 

I 0 0 

i= 30 0 

z 'V I + w 

u 0 a: 

6~~¥ 0~ w 

~ 

ON 

iJj dJ 0 20 'V 

~+ D ~+~OIJ 0 

~1: -t 0 EXPLANATION X 

~ 0 

0 SITE 

+ 213 

10 

fr~D !:,. 215 

X 231 X 'V 232 r§l 0 bedrock 

OIY----L----L----L----L---~----~--~--~----~ 

0 10 20 30 40 

MgO (PERCENT) 

Figure 4. Plot of MgO vs. Si02 contents. Rectangles, All 

laterites except those from sites 213, 215, 231, and 232. 

Solid curve, Curve calculated to fit data represented by 

rectangles. Dashed line, Curve calculated to fit data from 

sites 213, 215, 231, and 232. See text for discussion. 

Log Log Log Goe- Log 

Log Ni vs. Ni vs. Log Log Co Co vs. Log Co thite MgO 

Ni vs. Co vs. vs. vs. log vs. log log log vs. Fe20 3 MgO MnO Si02 Fe20 3 MgO MnO Fe20 3 

serpentine 

-0.76 0.77 0.91* 0.95* 

.8 .88* 

-.68 -0.87 0.9* -0.83 .78 .96* 

0.96* 

-.95* .99* .91 

.81 -.79 0.91* -.97* .98* -0.96* .96* .87 .94* 

.88* .6* .52 .9* .53 .74* 

.53 .62 

-.88* .95* .81 * .72* 

-.92* .92* -.88* .81 .94* .83* 

.67 .77 .86* .99* 

.33* .6* -.44* -.52* .63* .56* .71* 

80 

'V 

EXPLANATION 

70 SITE 

+ 213 !:,. 215 

X 231 

60 0 'V 232 

~~ 0 bedrock 

~~+ 50 ~ DO 

i= 

~D z 

w 

u 

a: 

w 40 ~ 

M 

ON 

Q) 

u.. 

30 

20 

10 0 "-..._ 

215 bedrock -- 0 ~---L----L----L----L---~--~L---~--~--~ 

0 10 20 30 40 

MgO (PERCENT) 

Figure 5. Plot of Fe20 3 vs. MgO contents. Rectangles, All 

laterites except those from sites 213, 215, 231, and 232. 

Solid curve, Curve calculated to fit data represented by 

rectangles. Dashed line, Curve calculated to fit data from 

sites 213, 215, 231, and 232. 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites E17 
where C1

c and Cle denote original and subsequent 

concentrati~ns of the "leached component." Since the 

concentration of the residual component (rs) is 

Crs= 100-Ctc, 

equation 4 may be rewritten as 

Crs=Crso +(100-Crs) . e -Ale· d. (5) 

When combined with equation 3, the variation of the 

residual components (rs0 denotes original residual 

component) with MgO may be stated as 

C =C +(100-C ) · e(AtciAMgO). (ln(l-(CMgdCMgOo))) (6) rs rso rso . 

Finally, the concentration of Fe20 3 may be modeled by 

assuming that the Fe20i(Fe20 3 + Al20 3) ratio is 0.79, a 

value consistent with the data in table 1. The concentration 

of Fe20 3 (CFe) is then given by 

CFe=0.79 · [Crs0 

+(100-Crs) 

. e(Alc/AMgO). (ln(l-(CMgdCMgO)))]. (7) 

The curve derived from this relation is plotted in figure 5 

(solid line) and provides a reasonable fit to the curved 

distribution of points, especially considering the 

assumptions that have been made. 

The models given above, however, apparently fail to 

reproduce the relations found in profiles for sites 213, 215, 

231, and 232. The fact that profiles for sites 231 and 232 

have evidently been mechanically mixed does little to 

explain their different patterns; the chemical patterns in 

another disturbed profile, those at site 216, for example, are 

modeled quite well. Also, the above equations depend only 

on the local chemical equilibrium between components and 

not on the ordering of the samples. Thus these patterns 

should not be affected by mechanical mixing. 

The most striking feature shared by all four of these 

profiles is a relatively large abundance of quartz (table 1). 

This abundance of quartz is also indicated by the vertical 

distribution of Si02 (table 2). In other profiles, Si02 clearly 

increases with depth. However, in these four profiles, 

quartz is most abundant at the top of the profile and results 

in high Si02 values that tend to offset the downward 

increase in Si02 due to increases in abundance of other 

silicate minerals. As a result, Si02 in profiles for sites 215, 

231, and 232 shows no vertical change, while only a minor 

increase in Si02 occurs at site 213. 

Golightly (1981) showed that the solubility of most 

magnesium silicate minerals found in laterites decreases 

with increasing pH. In contrast, the solubility of quartz is 

relatively independent of pH, while goethite has a solubility 

minimum at a pH of approximately 8. These relations 

indicate that in ground waters with relatively high pH, Si02 

will mostly be used up in the formation of the relatively 

insoluble secondary magnesium-bearing silicates. 

However, as ground-water pH decreases and the solubility 

of these magnesium-bearing phases increases, Si02 is more 

E18 Contributions to Commodity Geology Research 

likely to precipitate as quartz. The presence of quartz may 

thus be a useful pH indicator in some laterites (Golightly, 

1981). The large amounts of quartz in profiles from sites 

213, 215, 231, and 232, therefore, most likely indicate 

more acidic ground water at these four locations than at the 

other sample sites. 

In terms of equation 3, the increase in solubility of 

magnesium-silicates with respect to quartz as pH decreases 

will be expressed by increases in values of As/ AMg· The 

dashed line in figure 4 was calculated by using a larger 

value for this constant than was used in calculating the solid 

curve (6 vs. 2). The result is a reasonable fit to the 

Mg0-Si02 data for the quartz-rich samples. Similar 

reasoning indicates that decreases in ground-water pH 

should also be accompanied by increases in the term 

Ale/ AMgo given in equation 7. Figure 5 shows the result of 

increasing this constant from 2 (solid curve) to 5 (dashed 

line). 

Since the Mg0-Si02 and Mg0-Fe20 3data from these 

four profiles lie mostly on the nearly linear portion of these 

two dashed curves, it is not clear how accurately these 

equations fit the data, but it is clear that the observed data 

are consistent with behavior predicted by equations 3 and 7. 

It also should be noted that the curves in figures 4 and 5 are 

based on an ultramafic parent rock composition, while, to 

be treated accurately, the data for profile 215 should be 

fitted to curves defined by their different parent rock 

chemistry. 

As previously discussed, smectite is found only in the 

northernmost sample sites (fig. 1). Although the precise 

compositions of these minerals are not known, inference 

based on comparison with other laterites suggests that they 

should be nontronitic. The stability of some magnesiumbearing silicates common in laterites as well as that of 

magnesium-bearing nontronite from laterites in New Caledonia (Trescases, 1975) is plotted in figure 6. This plot is 

derived from the dissolution reaction for these minerals, 

which, in the case of serpentine, may be written as 

which has an equilibrium constant (Kd) of 

Kd=29.5=3log[Mg++]+2log[H4Si04]+6pH. (9) 

Reorganization of equation 9 as 

3(log[Mg ++]+2pH)=29.5-2log[H4Si04 ] (10) 

enables direct construction of figure 6. 

This plot shows that waters having a concentration of 

Mg + + and Si02 represented by point A will not precipitate 

talc or Mg-bearing nontronite. However, an increase in 

concentration of Mg + + and (or) Si02 may result in first the 

formation of talc (B) and then talc and nontronite (C). In 

most instances, smectite occurs only in poorly drained 

profiles where ground waters may be enriched in cations 
20 

19 

18 

17 

I 16 a. 

N 15 + 

+ 14 + 

0> 

~ 13 

0> 

0 12 .....J 

11 

10 

9 

8 

-5.4 -5 -4.6 -4.2 -3.8 -3.4 -3 -2.6 

Figure 6. Stability of some minerals found in laterites 

plotted as log (Mg++) + 2pH vs. log (H4Si04 ). A, B, and C 

represent three possible ground-water compositions. 

Methods of calculation are discussed in text. Data are 

from Trescases (1975), Golightly (1981), and Boeglin and 

others (1983). 

through prolonged interactions with the bedrock (Golightly, 

1981). 

In these laterite profiles, however, the smectitebearing profiles all occur on slopes in the topographically 

rugged Kalmiopsis Wilderness. Laterite profiles without 

smectite are situated on relatively level terraces or plateaus. 

Both environments are extremely well drained and, 

therefore, would normally not be expected to have smectite. 

However, study of laterites in New Caledonia (Trescases, 

1975) shows that ground waters on hillslopes are enriched 

in Si02 and Mg + + as a result of their movement down 

through laterite and across the bedrock that makes the 

hilltops. As a result, laterites on hillslopes typically contain 

smectite, while those from flatter, well-drained areas do 

not. The distribution of smectite in these laterite profiles is 

in accord with these observations. 

Three main conclusions may be drawn from the 

above discussion. First, the distribution of major oxides in 

these laterites follows patterns predicted by relatively 

simple mathematical models. Second, laterite mineralogy 

suggests that the pH of ground waters in four of these 

profiles was significantly more acidic than in others. This 

conclusion is consistent with the different patterns that 

MgO, Si02 , and Fe20 3 make in these profiles. Third, 

ground waters moving down hillslopes apparently became 

enriched in Mg + + and Si02 and, as a result, precipitated 

smectite. 

Relations between many of the other oxides in these 

laterites appear to be somewhat less complex. Good inter1.1 

1.0 

0.9 

0.8 

z 

0 

::::i 0.7 ....J 

~ 

a: 0.6 w 

a.. 

C/) 

1-

a: 0.5 

<( 

e::. 

d'>l 0.4 

t= 

0.3 

0.2 

0.1 

0 

0 

EXPLANATION 

SITE 

+ 211 

0 215 

0 all other sites 

4 8 12 

0 0 

8 0 

0 

6. 215 

16 

AIP3 (PERCENT) 

0 

20 24 

Figure 7. Plot of Al20 3 vs. Ti02 contents. Labeled triangles 

show values for bedrock at sites 211 and 215. X (values 

near origin) shows Al20 3 values for samples in which Ti02 

was below the detection limit of 0.02 weight percent. Solid 

line represents best fit to all data shown by rectangles; 

dashed line shows best fit for data from site 211. 

element correlations are observed between Al20 3 and Ti02 

(table 4) and define a nearly linear trend (fig. 7). Both these 

oxides are among the least mobile, and their nearly linear 

relation suggests that they are being residually enriched in 

about the same relative proportions as in the bedrock. Most 

bedrock values of Ti02 are below limits of analytical 

detection (table 1). However, Ti02 in bedrock from site 211 

was detected, and its ratio with Al20 3 is similar to those 

ratios in the overlying laterites (fig. 7). The best-fit line 

through the Ti02 -Al20 3 data (with values from profiles 213 

and 215 excepted) indicates a Ti02/Al20 3 ratio of 0.05. 

This value is near the middle of the range commonly 

observed in ultramafic rocks from ophiolite complexes 

(Coleman, 1977). 

Correlation between Fe20 3 and Al20 3 varies from 

strongly positive to highly negative (table 4; fig. 8). Many 

studies have shown that aluminum substitutes for iron 

within goethite, and it is therefore reasonable to assume that 

this substitution has occurred in cases where highly positive 

correlations of these elements are found. Not surprisingly, 

the profiles having the highest positive correlations (214, 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing laterites E19 
t= 

z 

w 

u 

c: 

w 

e:. M 

ON 

Q) 

u. 

80 

+ 

X X 

70 

0 

60 

50 

40 

30 • • 

20 ~I 

10Ww 

Do 

lo D 

• ot:J 

t4llco[Q] 

-t 

+ :tt- • + L'. 

-4-Ll 

• rv~ 

I; + 

• ~ 0 IV 

\l 215 

EXPLANATION 

SITE 

• 211 

• 213 

EB 214 

... 215 

• 216 

@ 217 

D 231 

+ 232 

0 233 

Ll 259 

X 261 

\l bedrock 

..... ... ... 

0&-~--~~--~~--~~--~~~~~~--~ 

0 4 8 12 16 20 24 

AIP3 (PERCENT) 

Figure 8. Plot of Al20 3 vs. Fe20 3 contents. Best-fit lines 

and slopes are given for data from sites 233, 217, 214, and 

259. (Note: Best-fit calculations for site 259 did not include 

data from circled open triangle. This datum, which was 

from the first sample in the profile, fell off the general 

trend of the other points and was considered to be 

anomalous.) 

217, 233, and 259) are also those that appear to have 

proportionately the smallest amounts of other aluminumbearing phases. Best-fit lines through data from these 

profiles indicate that the Fe20 3/ Al20 3 ratios vary between 

2.9 to 11.7. Natural goethite may contain up to 33 mole 

percent aluminum (Schwertmann, 1983), corresponding to 

an Fe20i Al20 3 ratio of 3 .1 or greater. With the exception 

of site 259, these data are within the range of natural 

goethites. The linear distribution of data from each of these 

sites suggests that the AI content of goethite varies between 

sites but remains relatively constant within a single profile. 

Conversely, poor or negative Al20 3-Fe20 3 correlations 

occur mostly in profiles where chlorite and (or) hornblende 

are relatively abundant. 

Simple models, however, do not appear to explain the 

distribution of nickel and cobalt in these profiles. To a large 

extent, the absence of simple controls on the distribution of 

these trace elements is due to their ability to reside in a 

E20 Contributions to Commodity Geology Research 

number of different minerals. In general, nickel increases 

with depth in these laterites, a relation consistent with that 

observed in many other laterites and attributable to the 

dissolution of nickel in the upper parts of the profile and 

reprecipitation in the lower parts where ground-water pH 

increases. Cobalt, in contrast, shows no consistent trend 

and, in fact, highest values commonly occur in middle parts 

of profiles. With the exception of a relatively small 

correlation in profile 231, significant correlation of cobalt 

and nickel does not occur within individual profiles (table 

4), thus confirming the independent behavior of nickel and 

cobalt. Interestingly, analyses of the data from all profiles 

result in a significant correlation of cobalt and nickel. A plot 

of cobalt and nickel (fig. 9) clearly shows that this 

correlation results from superimposing data from 

independent populations. 

The correlation data (table 4), however, does show 

that nickel occurs in two distinct associations. In the first 

(profiles 211, 213, 216, and 233), it is directly related to 

Si02 • Most of these also show a positive correlation with 

MgO and a negative relation with Fe20 3 ; in the second 

(profiles 217, 231, and 232), nickel correlates with Fe20 3 • 

Because Fe20 3 and MgO generally have high positive 

correlations, respectively, with abundances of goethite and 

serpentine (table 4), the nickel in profiles 211, 213, 216, 

and 233 probably occurs mostly as a substitution in 

serpentine, while nickel in 217, 231, and 232 is in goethite. 

There is, in contrast, no evidence of cobalt being 

associated with silicate minerals. Instead, cobalt is mostly 

positively correlated with either Fe20 3 (profiles 214, 216, 

217,231,259, and 261) orMnO (215, 217,231,232,259, 

and 261). Fe20 3 and MnO generally vary together (profiles 

217, 231, 259, and 261), and therefore it is not usually 

possible to determine if cobalt is mostly in goethite or in 

manganese oxides. That cobalt may occur within both 

phases is shown where significant correlation occurs with 

only Fe20 3 or MnO. For example, in profiles 214 and 216, 

cobalt is significantly positively correlated with Fe20 3 and 

not with MnO. In these profiles it is, therefore, likely that 

cobalt is hosted by goethite. Conversely, in profile 215 and 

232, cobalt is significantly correlated with MnO and not 

with Fe20 3 , indicating that cobalt probably is in manganese 

oxides. 

The preceding discussion of laterite chemistry 

provides no information as to the net gain or loss of 

chemical constituents during laterite formation. One way to 

estimate absolute changes in laterite chemistry is to 

compare element abundances with those of a constituent 

that is assumed to be unchanged. For the purposes of this 

study, Al20 3 has been used not only because it is known to 

be quite immobile (Golightly, 1981) but also because it is 

sufficiently abundant to be measured relatively accurately. 

The percentage net change in concentration of an element 

( Cx) relative to Al20 3 is calculated as 
3000 r-r-ITI-ol--.-1.-1'1-,l--.-1~1~1-.1--.-1~1~1-.1~~, 

EXPLANATION 

z 

0 

2800 r2600 -

2400 -

2200 -

2000 -

::::i 1800 - ...J 

~ a: 1600 -

w 

c.. 

~ 1400 fa: 

<t: e:. 1200 f0 

u 1000 1-

800 1-

600 1-

400 1-

200 ,..._ ~ 

SITE 

D 211 

+ 213 

0 214 

/',. 215 

X 216 

'V 217 

• 231 

* 232 

• 233 • ... 259 

® 261 

'V bedrock 

D 

• 

Dt 

• ® 

++ D 

*~ 

* D ® ® 

• [{] 

vt • 'V 

• +"'f_*e7/fc~+ * D * o~x 

·:·...-~~~·~X~ ~~'VVV 

'V'V 'V 'V 

® 

® 

® ® 

• • • * • 

• 

'V'V 'V 'V 

0 fl I l I I I I I I I I I I I I I I 

-

-

-

-

-

-

-

-

-

-

-

-

-

-

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 

Ni (PARTS PER MILLION) 

Figure 9. Plot of nickel vs. cobalt contents. 

where Xs and (Al20 3) 5 are the values of component x and 

Al20 3 in laterite, and XP and (Al20 3)P are those values in 

the parent rock. Percentage net changes in six constituents 

based on this equation are given in table 5; variations in 

profiles 216 and 233 are plotted in figures 2 and 3. 

The trends in net compositional change are similar in 

most profiles. With the exception of the mineralogically and 

chemically distinct profile 215, most profile averages show 

an ordering from most depleted component to least of MgO, 

Si02 , Ni, MnO, Fe20 3 , and Co. Exceptions occur in profile 

211, where the average MnO value is more depleted than 

the nickel value, and in profiles 214, 231, and 259, where 

the average cobalt values are just slightly more depleted 

than the averages for Fe20 3 . These profiles almost all show 

an overall loss of all their major components, with enrichments only evident in profiles 211 (Co, Ni, Fe20 3), 233 

(Co), and 261 (Co, Fe20 3). In contrast to these profiles, 

values from sample site 215 differ significantly. Significant 

enrichments occur in average values of nickel, Fe20 3 , and 

cobalt, with nickel showing the largest amounts of enrichment. 

The most surprising feature of these patterns is the 

absence of consistent and significant increases in nickel. 

Hotz ( 1964) conducted a similar study using data from the 

Riddle laterite deposit and from laterite on Eight Dollar 

Mountain (located 15 km east of Pearson Peak; fig. 1). In 

both profiles, nickel was found to be the most enriched 

component, with net gains commonly exceeding 120 percent. Cobalt and iron also typically showed net increases. 

The general order of enrichment determined by Hotz was, 

from most depleted to most enriched, MgO, Si02 , Mn, Fe, 

Co, and Ni. With the exception of nickel, this sequence is 

similar to the one found in these laterites. 

CONCLUSIONS 

Ten of the eleven laterites studied formed over 

serpentinized peridotite and, in general, are mineralogically 

and chemically similar. All contain serpentine, chlorite, 

goethite, and maghemite. Profiles located on hillslopes also 

have smectite. Quartz, talc, hornblende, orthopyroxene, 

and tremolite are additional components of some laterites. 

Within profiles that have not been physically disrupted, the 

least soluble minerals (mostly goethite) are most abundant 

at tops of profiles, and the more soluble phases generally 

increase with depth. 

Mean values of major chemical constituents in these 

10 profiles are nickel, 0.64 weight percent; cobalt, 0.063 

weight percent; Si02 , 18.3 weight percent; MgO, 5.0 

weight percent; Fe20 3 , 46.4 weight percent; Al20 3 , 8.0 

weight percent; and MnO, 0. 51 weight percent. Amounts of 

MgO and Fe20 3 generally directly reflect abundance, 

respectively, of serpentine and goethite. These compositions are similar to those of other laterites described from 

this area. 

The profile at site 215 differs from the others in 

having formed over a hornblende-rich parent rock. These 

laterites are also distinguished by having relatively large 

amounts of quartz, chlorite, and talc and by low values of 

MgO and nickel (having mean values of 2.4 and 0.11 

weight percent, respectively). 

The restriction of smectite to laterites located on 

hillslopes results from local variations in ground-water 

chemistry. Precipitation of smectite is favored by high 

concentrations of Si02 and MgO in ground water, but the 

excellent drainage present in these laterites tends to prevent 

enrichment in these components. As a result of downslope 

flow over serpentine, however, waters on hillsides locally 

have dissolved enough Si02 and MgO to precipitate smectite. 

The distribution of MgO, Si02 , and Fe20 3 in these 

laterites appears to follow trends predicted by the relatively 

simple equation: 

Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites E21 
Table 5. Net change in laterite composition 

[Calculations made assuming no change in Al20 3 , as discussed in text; whole-rock values from site 233 were used to calculate values for profiles 231 and 

232. IS, insufficient sample] 

Site 

sample 

number 

Sample 

depth 

(m) 

211-1 . . . 0.23 

211-2 . . . .38 

211-3... .64 

211-4 . . . .92 

211-5 . . . 1.22 

211-6 . . . 1.53 

211-7 . . . 1.83 

211-8 . . . 2.14 

213-1 . . . .15 

213-2... .31 

213-3 . . . .61 

213-4. . . .92 

213-5 . . . 1.22 

213-6 . . . 1.53 

213-7 . . . 1.88 

214-1 . . . .15 

214-2 . . . .31 

214-3 . . . .61 

214-4... .92 

214-5 . . . 1.22 

214-6 . . . 1.37 

215-1 . . . .15 

215-2 . . . .31 

215-3 . . . .61 

215-4... .92 

215-5 . . . 1.22 

216-1 . . . .15 

216-2 . . . .31 

216-3 . . . .61 

216-4... .92 

216-5 . . . 1.22 

217-1 . . . .15 

217-2... .31 

217-3 . . . .61 

217-4... .92 

217-5 . . . 1.22 

217-6... 1.53 

231-1 . . . .46 

231-2 . . . .87 

231-3 . . . 1.20 

231-4 . . . 1.55 

231-5 . . . 2.01 

231-6... 2.32 

231-7... 2.62 

231-8 . . . 2.93 

231-9 . . . 3.23 

231-10 . . 3.54 

231-11 . . 3.84 

231-12 . . 4.15 

231-13 . . 4.45 

Percent change 

Ni Co 

-59.8 13.8 -94.5 

-22.4 187.8 -88.0 

-8.6 159.6 -82.6 

-25.0 91.1 -85.7 

-2.5 120.4 -79.5 

47.4 173.6 -70.4 

47.0 156.9 -72.5 

85.2 142.3 -65.5 

-91.9 -68.7 -97.7 

-92.0 -69.1 -97.2 

-89.1 -63.7 -97.2 

-85.0 -21.4 -96.2 

-80.4 -5.8 -94.5 

-82.7 -40.4 -93.5 

-65.4 -28.5 -87.9 

-95.3 -87.3 -98.0 

-93.4 -79.9 -97.3 

-87.1 -78.3 -93.8 

-86.3 -76.9 -92.4 

-91.2 -82.4 -94.8 

-91.3 -82.7 -94.0 

199.8 140.5 -64.6 

202.5 129.8 -62.2 

198.5 126.8 -59.9 

234.4 81.1 -57.3 

277.3 115.6 -60.3 

-57.5 -15.2 -84.4 

-55.2 6.3 -84.6 

-53.2 -8.2 -81.3 

-30.8 22.8 -73.2 

-40.9 -14.3 -76.0 

-88.3 -43.7 -97.9 

-89.2 -44.9 -95.5 

-79.7 -23.3 -84.6 

-68.1 -14.8 -72.3 

-67.6 -5.3 -69.3 

-68.4 -2.7 -66.9 

-97.4 -82.0 -98.2 

-96.9 -76.5 -98.5 

-97.1 -83.9 -98.4 

-97.5 -84.2 -98.4 

-97.7 -85.8 -98.5 

-98.0 -89.6 -98.6 

-97.8 -89.9 -98.6 

-97.8 -87.1 -98.3 

-97.8 -82.4 -98.3 

-97.5 -89.0 -98.7 

-97.4 -89.4 -98.7 

-97.1 -90.4 -98.7 

-97.1 -89.7 -98.8 

-27.6 

5.1 

-4.5 

-10.4 

8.9 

56.2 

64.6 

69.4 

-64.7 

-68.4 

-49.9 

-37.3 

-27.8 

-43.7 

-22.6 

-72.9 

-65.0 

-63.6 

-63.2 

-69.0 

-69.9 

158.3 

159.0 

144.8 

136.2 

175.0 

-20.5 

-6.7 

-18.6 

2.6 

-19.3 

-34.8 

-34.4 

-27.9 

-19.8 

-18.2 

-19.8 

-77.6 

-75.6 

-78.5 

-79.4 

-78.7 

-80.1 

-79.9 

-79.1 

-78.0 

-76.8 

-76.9 

-76.8 

-73.8 

MgO 

-96.0 

-91.9 

-89.3 

-92.5 

-85.8 

-78.7 

-80.6 

-76.2 

-99.2 

-99.2 

-99.3 

-98.7 

-99.0 

-98.7 

-95.7 

-99.4 

-99.0 

-96.2 

-95.0 

-97.0 

-96.3 

-81.7 

-84.9 

-80.1 

-76.2 

-71.6 

-92.8 

-92.3 

-92.0 

-87.3 

-89.1 

-99.1 

-99.1 

-89.2 

-79.1 

-73.3 

-69.6 

-99.5 

-99.7 

-99.8 

-99.8 

-99.6 

-99.8 

-99.9 

-99.6 

-99.5 

-99.8 

-99.8 

-99.8 

-99.8 

E22 Contributions to Commodity Geology Research 

MnO 

-63.5 

-20.2 

-49.6 

-49.5 

-37.2 

-6.7 

5.6 

3.9 

-76.5 

-75.3 

-78.2 

-93.8 

-19.8 

-38.2 

.9 

-91.9 

-87.8 

-81.3 

-79.0 

-83.2 

-83.3 

24.0 

25.1 

5.8 

-95.5 

-48.1 

-18.4 

-26.3 

-33.7 

-12.0 

-35.7 

-3.5 

-52.0 

-37.1 

-35.8 

-33.6 

-40.1 

-81.0 

-87.7 

-89.1 

-89.0 

-86.7 

-88.9 

-90.0 

-88.5 

-87.7 

-88.5 

-88.8 

-89.7 

-88.3 

Site 

sample 

number 

Sample 

depth 

(m) 

231-14 . . 4.76 

231-15 . . 5.06 

231-16 . . 5.37 

231-17 . . 5.67 

231-18 . . 5.98 

231-19 . . 6.28 

231-20 . . 6.59 

232-1 . . . .31 

232-2... .61 

232-3 . . . 1.22 

232-4... 1.53 

232-5 . . . 1.83 

232-6... 2.14 

232-7... 2.44 

232-8 . . . 2.75 

232-9 . . . 3.05 

232-10 . . 3.36 

232-11 . . 3.66 

232-12 . . 3.97 

232-13 . . 4.27 

232-14 . . 4.58 

233-1 . . . .31 

233-2... .61 

233-3 . . . 1.22 

233-4... 1.53 

233-5 . . . 1.83 

233-6 . . . 2.14 

233-7... 2.44 

233-8 . . . 2.75 

233-9 . . . 3.05 

233-10 . . 3.36 

233-11 . . 3.66 

233-12 . . 3.97 

259-1 . . . .15 

259-2 . . . .31 

259-3 . . . .61 

259-4... .92 

259-5 . . . 1.22 

259-6... 1.53 

259-7... 1.83 

259-8 . . . 2.14 

261-1 . . . .15 

261-2... .31 

261-3 . . . .61 

261-4 . . . .92 

261-5 . . . 1.22 

261-6... 1.53 

261-7 . . . 1.83 

261-8... 2.14 

261-9... 2.44 

Ni 

-95.5 

-96.1 

-95.5 

-93.6 

-92.9 

-94.7 

-95.3 

-95.7 

-95.9 

-95.0 

-97.3 

-94.8 

-92.9 

-95.1 

-95.0 

-93.0 

-89.1 

-91.3 

-95.3 

-95.2 

-93.6 

-88.9 

-87.8 

-87.8 

-81.5 

-63.3 

-65.5 

-66.9 

-56.4 

-62.8 

IS 

IS 

-54.8 

-74.0 

-63.4 

-61.4 

-58.3 

-50.0 

-45.9 

-29.5 

4.5 

-68.3 

-68.1 

-69.4 

-40.0 

-7.1 

-10.6 

-43.5 

-48.8 

-46.0 

Co 

-83.5 

-78.9 

-77.8 

-62.4 

-43.5 

4.5 

-29.9 

-67.3 

-68.7 

-65.1 

-80.3 

-53.5 

-56.0 

-54.9 

-73.9 

-68.6 

-52.6 

-49.5 

-65.1 

-66.4 

-48.1 

-45.9 

-27.4 

18.2 

47.1 

11.4 

49.7 

69.7 

54.5 

37.8 

IS 

IS 

42.5 

-49.3 

-46.5 

-35.5 

-21.5 

-37.0 

-31.3 

-15.9 

9.8 

-25.5 

-45.3 

-28.1 

157.3 

126.9 

82.5 

-10.2 

-11.4 

-18.6 

Percent change 

-98.2 

-98.2 

-98.1 

-98.4 

-98.9 

-98.4 

-98.2 

-97.2 

-97.1 

-97.0 

-97.1 

-97.0 

-98.0 

-97.6 

-97.4 

-98.7 

-99.3 

-98.3 

-97.2 

-97.1 

-97.8 

-98.8 

-99.0 

-98.0 

-97.0 

-91.1 

-93.0 

-94.8 

-90.0 

-90.3 

IS 

IS 

-91.3 

-92.3 

-94.1 

-92.6 

-88.6 

-85.3 

-78.8 

-71.3 

-60.1 

-99.0 

-99.1 

-99.2 

-98.7 

-98.0 

-97.6 

-97.6 

-97.6 

-95.6 

-66.2 

-70.6 

-67.8 

-57.0 

-46.0 

-61.3 

-68.9 

-77.7 

-78.3 

-75.5 

-83.7 

-73.2 

-47.7 

-75.2 

-75.3 

-65.5 

-9.1 

-38.3 

-76.6 

-76.0 

-68.1 

-32.7 

-23.2 

-23.8 

-15.4 

-9.1 

-6.1 

34.0 

.9 

-20.5 

IS 

IS 

1.2 

-50.8 

-34.9 

-28.3 

-29.0 

-28.7 

-27.6 

-19.0 

-3.1 

-23.8 

-28.3 

-21.6 

30.5 

53.0 

27.8 

-12.1 

-10.0 

-6.7 

MgO 

-99.8 

-99.8 

-99.8 

-99.7 

-99.7 

-99.6 

-99.5 

-99.4 

-99.4 

-99.4 

-99.5 

-99.3 

-99.5 

-99.6 

-99.6 

-99.8 

-99.8 

-99.6 

-99.5 

-99.4 

-99.5 

-99.6 

-99.6 

-99.2 

-98.7 

-95.4 

-96.4 

-97.5 

-94.6 

-94.8 

IS 

IS 

-95.3 

-96.5 

-97.6 

-96.3 

-92.6 

-89.5 

-84.3 

-77.2 

-68.6 

-99.7 

-99.8 

-99.8 

-99.7 

-99.4 

-99.2 

-99.2 

-99.2 

-97.1 

MnO 

-84.0 

-83.7 

-80.9 

-75.4 

-68.9 

-65.5 

-67.2 

-73.1 

-73.5 

-73.3 

-76.2 

-67.1 

-77.7 

-67.6 

-82.5 

-88.2 

-84.9 

-76.0 

-75.6 

-75.9 

-75.0 

-71.7 

-70.1 

-59.2 

-37.8 

-23.3 

10.2 

56.5 

44.1 

-1.2 

IS 

IS 

29.2 

-48.4 

-63.7 

-46.4 

-16.5 

-40.0 

-26.4 

-18.3 

6.6 

-61.8 

-69.3 

-62.2 

11.1 

10.2 

-4.0 

-43.1 

-37.2 

-36.2 
where: 

Cx and Cy are the concentration of components x and y in 

the laterite, 

Cx0 and CYo are the initial concentration of x andy, and 

Ax and Ay are constants related to the solubility of x and 

y. 

Trends fitted by this equation and its derivatives for 

profiles 213, 215, 231 , and 23 2 differ from those in the 

other laterites. These four profiles contain relatively large 

amounts of quartz, which commonly is a mineralogical 

indicator of relatively acidic ground waters. The shift in the 

major element trends in these four profiles from those in the 

other laterites is consistent with the presence of ground 

water having a lower pH. 

The distribution of other oxides reveals a variety of 

relations. Good positive correlation exists between 

abundance of Al20 3 and Ti02 • Both are relatively immobile 

and appear to be residually enriched in about the same 

proportions as occur in the parent rock. Al20 3 and Fe20 3 , in 

contrast, are strongly positively correlated in goethite-rich 

laterites, but not in laterites having large amounts of 

aluminum-bearing minerals. It is probable that, where 

positively correlated, most of the aluminum occurs as a 

substitution for iron in goethite. Fairly constant 

Al20 3/Fe20 3 ratios occur in the goethite-rich profiles and 

indicate a uniformity of goethite compositions within 

individual laterites. Nickel in some profiles is positively 

correlated with Fe20 3 , indicating that it occurs in goethite; 

in other laterites, nickel is mostly present in serpentine as 

shown by its good correlation with MgO. Cobalt, on the 

other hand, apparently occurs primarily in either goethite or 

in manganese oxides, but in most profiles its host phase 

could not actually be determined. 

Calculations of net changes in laterite chemistry show 

that loss of chemical components during weathering 

generally occurs in a well-defined order. This sequence is, 

from most depleted to most enriched, MgO, Si02 , Ni, 

MnO, Fe20 3 , and Co. The observed net chemical changes 

in these deposits differ from those observed in the adjacent 

laterite on Eight Dollar Mountain and the deposit at Riddle, 

Oreg., in two ways. First, nickel is the most enriched 

component in those deposits. Second, the large amounts of 

net enrichment in nickel and cobalt observed at Eight Dollar 

Mountain and at Riddle were not found in the laterites 

studied here. 

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laterite deposits, Del Norte County, Calif.: U.S. Bureau of 

Mines Report of Investigations 6206, 19 p. 

Boeglin, J.L., Melfi, A.J., Nahon, D., Paquet, H., and Tardy, 

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the 2nd International Lateritisation Seminar on Lateritisation 

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Coleman, R.G., 1977, Ophiolites: New York, Springer-Verlag, 

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omnivorous process for laterite deposits, in Evans, D.J.I., 

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laterite symposium: New York, Society of Mining Engineers 

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B.J., ed., Economic Geology 75th Anniversary Volume: p. 

710-735. 

Hotz, P.E., 1964, Nickeliferous laterites in southwestern Oregon 

and northwestern California: Economic Geology, v. 59, no. 

3, p. 355-396. 

Hundhausen R.J., McWilliams, J.R., and Banning, L.H., 1954, 

Preliminary investigation of the Red Flats nickel deposit, 

Curry County, Oregon: U.S. Bureau of Mines Report of 

Investigations 5072, 19 p. 

Irwin, W.P., 1977, Ophiolitic terranes of California, Oregon, and 

Nevada, in Coleman, R.G. and Irwin, W.P., eds., North 

American ophiolites: Oregon Department of Geology and 

Mineral Industries Bulletin 95, p. 75-92. 

Kukura, M.E., Stevens, L.G., and Auck, Y.T., 1979, Development of the UOP process for oxide silicate ores of nickel and 

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Mining Engineers of the American Institute of Mining, 

Metallurgical and Petroleum Engineers, p. 527-552. 

Libbey, F.W., Lowry, W.D., and Mason, R.S., 1947, Nickelbearing laterite, Red Flats, Curry County, Oregon: Ore Bin, 

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Nickel-Mineralogy and Chemical Composition of Some Nickel-Bearing Laterites E23 
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R.W., Lipin, B.R., Foose, M.P., and Gray, F., 1982, 

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Paper 20, 68 p. 

Schwertmann, U., 1983, The role of aluminium in iron oxide 

systems, in Melfi, A.J., and Carvalho, A., eds., LateritisaE24 Contributions to Commodity Geology Research 

tion processes-Proceedings of the II International Seminar 

on Lateritisation Processes: University of Sao Paulo, Brazil, 

p. 65-68. 

Siemens, R.E., Good, P.C., and Stickney, W.A., 1975, Recovery 

of nickel and cobalt from low-grade domestic laterites: U.S. 

Bureau of Mines Report of Investigations 8027, 14 p. 

Trescases, Jean-Jacques, 1975, L'evolution geochimique supergene des roches ultrabasiques en zone tropicale-Formation 

des gisements nickeliferes de Nouvelle-Caledonia: Memoires 

O.R.S.T.O.M., no. 78, 259 p. 
Chapter F 

Platinum-Group ElementsOccurrences in the Bethlehem Porphyry 

Copper Deposits, Highland Valley, 

British Columbia 

By NORMAN J PAGE, JOSEPH A. BRISKEY, and LEUNG MEl 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract Fl 

Introduction Fl 

Acknowledgments F2 

Geologic Setting F2 

Analytical Methods and Results F2 

Discussion F3 

References F6 

FIGURES 

1. Map showing location of the Guichon Creek batholith and the Bethlehem porphyry 

copper-molybdenum deposits in the southern part of the Canadian Cordillera F4 

2. Geologic maps of the Bethlehem deposits showing the locations of samples 

analyzed for platinum-group elements FS 

3. Diagram showing chondrite-normalized ratios for palladium, platinum, and 

rhodium averages for the sample groupings defined in table 2 from the Guichon 

Creek batholith and the Bethlehem porphyry deposits F6 

TABLES 

1. Palladium, platinum, and rhodium analyses and description of samples from the 

Guichon Creek batholith and the Bethlehem porphyry copper deposits, British 

Columbia F3 

2. Average, standard deviation, and number of analyses of samples containing 

detectable palladium, platinum, and rhodium in mineralogic and petrologic 

groupings of the Guichon Creek batholith and Bethlehem porphyry copper 

deposits F6 

Contents Ill 

Platinum-Group Elements-Occurrences in the 

Bethlehem Porphyry Copper Deposits, Highland 

Valley, British Columbia 

By Norman J Page, joseph A. Briskey, and Leung Mei 

Abstract 

Samples of unaltered and of altered and mineralized 

rocks from the Bethlehem porphyry copper deposits, and 

from the host Guichon Creek batholith, are analyzed for 

platinum-group elements. Iridium and ruthenium are not 

detected at levels of 20 ppb (parts per billion) and 100 ppb, 

respectively. On the average, altered and mineralized 

rocks are slightly enriched in palladium, platinum, and 

rhodium compared to unaltered and unmineralized rocks. 

Within the group of relatively unaltered and mineralized 

rocks, the younger phases have slightly higher platinum 

concentrations, and with the altered and mineralized 

rocks, the palladium content tends to increase from the 

propylitic to the potassic zone. Highly mineralized rocks 

tend to have higher concentrations of the three platinumgroup elements. The highest palladium, platinum, and 

rhodium contents are 17, 14, and 411 ppb; however, most 

contents average near 1, 2, and 0.6 ppb for palladium, 

platinum, and rhodium, respectively. 

INTRODUCTION 

Platinum-group elements (PGE) are known to occur 

in porphyry copper systems, but their concentrations and 

distributions are generally unknown. Ageton and Ryan 

( 1970) estimated that copper ores average about 1 troy 

ounce of PGE per 6,000 short tons of ore or 5.7 ppb (parts 

per billion). Information for many individual deposits is 

limited. On the basis of Eilers' (1913) analyses of blister 

copper, the Bingham porphyry copper deposit probably 

contains platinum and palladium in the ore at some low 

concentration. He found 0.0034 oz/ton platinum (106.3 

ppb) and 0.0118 oz/ton palladium (405 ppb) in the blister 

copper. Smith (1976) reported that ore from the porphyry 

copper deposits near Ely, Nev., in the Robinson mining 

district, contained an average of 0.0004 oz/ton palladium 

(14 ppb) and 0.0001 oz/ton platinum (3.4 ppb). Studies in 

the Iron Canyon area, Nev., which is on the northeast 

outermost fringes of the Copper Canyon porphyry system, 

show that palladium was detected in 137 of 270 rock 

samples analyzed. The palladium had an average 

concentration of 3.4 ppb, and the highest concentration was 

20 ppb (Carlson and others, 1976; Theodore and others, 

1976; Page and others, 1978). Palladium in rocks from Iron 

Canyon classified as granitic porphyries had an average of 

3 ppb and a maximum of 7 ppb. Recently, some PGE data 

from alkaline-rock-hosted porphyry copper systems have 

become available (Finch and others, 1983; Mutschler and 

others, 1984). Some of these systems were estimated to 

have 100 to 300 ppb palladium and 10 to 500 ppm platinum 

in copper-sulfide concentrates. Eckle (1949) identified PGE 

in the La Plata district in Colorado; Werle and others (1984) 

reported 1,900 to 2,300 ppb palladium and 2,900 to 3,900 

ppb platinum in copper-sulfide concentrates from the 

alkaline Allard stock of the La Plata district. The rocks from 

which these concentrates were derived would have much 

lower amounts of platinum-group elements. 

Samples of unaltered and of altered and mineralized 

rocks from the Bethlehem porphyry copper deposits, and 

from the host Guichon Creek batholith, were analyzed with 

the following goals in mind: ( 1) to perform a reconnaissance 

survey of the levels of PGE concentration present in a 

calc-alkaline porphyry system, (2) to evaluate whether 

documentable changes occur in PGE concentration during 

alteration and mineralization, and (3) to investigate the 

potential of PGE geochemistry in suggesting sources for 

metals in porphyry systems. The Bethlehem porphyry 

copper deposits, 400 km by highway northeast of Vancouver, B.C., are near the center of the 202- to 205-m.y.-old 

Guichon Creek batholith. This batholith is a concentrically 

zoned, chemically primitive, calc-alkaline pluton that 

intrudes oceanic assemblages and island-arc lithologies 

(Briskey and Bellamy, 1976; Briskey, 1980; Briskey and 

others, 1981). This communication will review briefly the 

geologic setting as background for the PGE geochemistry, 

present the analytical techniques and analyses for platinumgroup elements, and give a preliminary evaluation of the 

significance of those results. 

Platinum-Group Elements-The Bethlehem Porphyry Copper Deposits F1 
ACKNOWLEDGMENTS 

The authors are grateful to the former Bethlehem 

Copper Corporation, to its vice president for exploration, 

Henry G. Ewanchuk, and to Cominco Limited for 

supporting this and other detailed studies of the Bethlehem 

deposits. Numerous discussions of the geology of the 

deposits with William J. McMillan, Pantellis P. Tsaparas, 

Michael B. Jones, Robert A. Schmuck, James M. Allen, 

and especially Cyrus W. Field were invaluable and are 

sincerely appreciated. Cyrus W. Field, William J. 

McMillan, Ted G. Theodore, and Dennis P. Cox critically 

reviewed and improved the manuscript. This study was in 

part supported by grants from the Geological Society of 

America and from Sigma Xi. 

GEOLOGIC SETTING 

Within the Intermontane belt of the Canadian 

Cordillera, the Upper Triassic Guichon Creek batholith 

intrudes island-arc lithologies of the Upper Triassic to 

perhaps Middle Jurassic Nicola Group (McMillian, 1978). 

The Nicola Group is shown as Upper Triassic volcanic and 

sedimentary rocks in figure 1. The batholith (fig. 1) is a 

concentrically zoned calc-alkaline pluton, which contains 

major intrusive phases that become progressively younger 

and change in composition from quartz diorite and diorite of 

the peripheral hybrid (border) phase; through quartz diorite 

and granodiorite of the Guichon variety; to granodiorites of 

the Chataway variety, the Bethlehem phase, and the Skeena 

variety; to a core of granodiorite and quartz monzonite of 

the Bethsaida phase (McMillan, 1976, 1978). The 

mineralogy and texture of these units are typical of many 

calc-alkaline suites of the Coast Plutonic Complex of 

British Columbia, and of island-arc and continentalmarginal-arc tectonic settings (Briskey and others, 1981). 

The Bethlehem deposits formed along an irregular 

intrusive contact separating two major plutonic units of the 

Guichon Creek batholith (fig. 2A). Older Guichon variety 

granodiorite is intruded by younger Bethlehem phase granodiorite that forms a digitated northward-elongated apophysis along which is also localized a porphyry dike swarm that 

is most closely related in time and space with the ore 

deposits. Intrusive breccias; dacite porphyry dikes; small 

masses of "granite," granodiorite, and porphyritic quartz 

latite; dikes of silicic aplite; faults and fractures; and 

hydrothermal mineralization and alteration all are localized 

along digitations in the contact of the apophysis. 

Hydrothermal alteration generally has a zonal 

development within the ore deposits, with the distribution 

of epidote and secondary biotite forming a roughly 

concentric zonal pattern (Briskey and others, 1981). Bpidote defines the peripheral zone of propylitic alteration, and 

F2 Contributions to Commodity Geology Research 

secondary biotite the central potassic alteration core. In 

between is an area dominated by white mica and chlorite 

that is equivalent to phyllic alteration. Significant hydrothermal alteration is restricted to the immediate areas of 

orebodies; only propylitic and zeolite assemblages extend 

beyond the limits of conspicuous copper sulfide minerals. 

Hypogene metallic minerals in the Bethlehem 

deposits include chalcopyrite, bornite, pyrite, specularite, 

molybdenite, and minor magnetite and chalcocite. In the 

Jersey deposit, and probably in the Huestis and Iona 

deposits, there is a zonation of iron-bearing metallic 

minerals (Briskey and Bellamy, 1976). Vein-controlled 

specularite occurs peripheral to pyrite, each forming 

crudely concentric zones about a bornite-rich core. Though 

chalcopyrite is most abundant within the outer limits of the 

pyrite zones, it occurs throughout the deposits. Low-grade 

copper mineralization coincides with the pyrite halo, and 

high-grade copper occurs in the bornite-rich core. Molybdenite is distributed sporadically and is commonly peripheral 

to the central parts of ore zones. The copper content of 

unaltered Guichon and Bethlehem granodiorite in the 

vicinity of the deposits is 223 and 25 ppm, respectively, and 

the average content increases inward to the potassic zone 

where analyzed samples average 5,200 and 3,200 ppm, 

respectively (Briskey, 1980). Thus, type of alteration 

roughly corresponds to the copper content of the rock. 

Characteristics of the hypogene metallic mineral 

assemblage include ( 1) low total sulfide content (average 

<2 volume percent), (2) sparse pyrite (average <1 volume 

percent in the halo zone, and (3) high bornite to chalcopyrite ratios (> 1) in the bornite-rich core. 

Details of mineralogy, petrology, geochemistry, and 

geology that supplement this brief description are given by 

Briskey and Bellamy (1976), Briskey (1980), and Briskey 

and others (1981). 

ANALYTICAL METHODS AND RESULTS 

Analyses of platinum-group elements were performed 

( 1) on grab and composite samples of unaltered rocks 

representing the major phases of the batholith and (2) on 

unaltered, altered, and mineralized grab samples from the 

porphyry copper systems. Sample descriptions and 

analytical results for palladium, platinum, and rhodium are 

given in table 1. Locations of individual rock samples are 

shown on figures 1 and 2. 

The samples were analyzed for platinum, palladium, 

and rhodium by using a fire assay preconcentration with 

gold wire extraction (Haffty and others, 1977) followed by 

a graphite furnace atomic absorption technique (Simon and 

others, 1978; Page and others, 1980). The samples were 

analyzed in two groups. Detection limits for one group were 

0.1, 1.0, and 0.1 ppb of palladium, platinum, and rhodium, 
Table 1. Palladium, platinum, and rhodium analyses and description of samples from the Guichon Creek batholith and 

the Bethlehem porphyry copper deposits, British Columbia 

[Sample numbers used by Briskey (1980) are in parentheses. Samples preceded by asterisks are composite samples. Analysts: L. Mei and M. Doughten] 

Field number Pd Pt Rh Sample 

description 

Major plutonic units of Guichon Creek batholith 

*GB-5 (25) ......... 1.3 <1 0.2 Bethsaida phase. 

*GB-1 (23) ......... <1 .3 Skeena variety. 

GB-2-72 (30) ........ .7 <1 .1 Witches Brook 

phase. 

*GB-2 (19) ......... .6 <1 .2 Bethlehem phaseHighland Valley 

phase. 

*GB-7 (11) ......... 1.5 <1 <.5 Chataway variety. 

*GB-6 (9) .......... 1.6 <1 <.5 Guichon variety. 

*GB-3 (1) .......... .5 1 <.5 Hybrid (border) 

hase. 

Weakly altered and weakly mineralized dikes and small intrusive masses from 

the Bethlehem porphyry property 

J-B21-30 (64) . . . . . . . <0.5 

J-X39-23 (54) . . . . . . . 1 

BTH-8-70 (52). . . . . . . .55 

J-D0-18 (50) . . . . . . . . <.5 

BTH-4-70 (56). . . . . . . .7 

J-F13-65 (66). . . . . . . . .65 

J-D39-8 (78) . . . . . . . . <.5 

J-I-53 (74)....... . . . <.5 

BTH-27-72 (47)...... <.5 

BTH-28-72 ( 45) . . . . . . . 7 

H-4533-17 (43) . . . . . . .95 

H-HR-7 (17) . . . . . . . . 1.1 

J-E9-80 (16) . . . . . . . . .4 

J-B233-175 (35) ..... . 

H-5033-2 (38)....... <.1 

BTH-11-72 (7) ...... . 

J-D24-2 (5) ........ . 

J-X18-80 (6) ....... . 

.95 

1 

1.6 

<1 

1.6 

<1 

<1 

<1 

1.9 

1.8 

2.4 

<1 

<1 

<1 

<1 

<1 

1.5 

<0.5 Dacite porphyry. 

<.5 Do. 

<.5 Do. 

<.5 Do. 

<.5 Do. 

<.5 Dacite porphyry. 

<.5 K-feldspar-rich 

aplite. 

< .5 K-feldspar-poor 

aplite. 

< .5 Granite. 

<.5 Granodiorite. 

< .5 Porphyritic quartz 

latite. 

< .1 Bethlehem phase. 

<.1 Do. 

< .5 Bethlehem 

porphyry. 

.5 Bethlehem 

leucophase. 

<.5 Guichon variety. 

<.5 Do. 

. 6 Leucocratic Guichon 

varlet . 

Altered and mineralized rocks from the Bethlehem porphyry property 

J-D30-70 (88) . . . . . . . 0.9 

J-C12-45 (86) . . . . . . . <.5 

J-X14-50 (84) . . . . . . . 1.2 

J-2-5 (81) . . . . . . . . . . .75 

J-E1-65D (106) . . . . . . .85 

J-B29-230 (111). . . . . . . 6 

J-B234-106 (113) .... . 

J-B234-192 (114) .... . 

J-B234-291 (115). . . . . .5 

J-B52-153 (102)...... 1.7 

J-B18-367 (100). . . . . . 1.8 

J-X33--0 (99) . . . . . . . . .75 

J-R2-9 (93) . . . . . . . . . 2 

J-R0-40 (92) . . . . . . . . 2.2 

H-4533-6 (116) . . . . . . <.5 

J-U6-45 (126) . . . . . . . <.5 

2 

<1 

<1 

<1 

<1 

<1 

1.5 

1.4 

1.5 

1.6 

1.6 

2 

2.1 

2.3 

1.5 

1.5 

<0.5 Propylitically altered 

Bethlehem phase. 

<.5 Do. 

<.5 Propylitically altered 

Guichon variety. 

<.5 Do. 

.5 Phyllically altered 

Bethlehem phase. 

<.5 Do. 

8 Do. 

.85 Do. 

.5 Do. 

. 75 Phyllically altered 

Guichon variety. 

<.5 Do. 

<.5 Do. 

<.5 Do. 

<.5 Do. 

<.5 Potassically altered 

Bethlehem phase. 

<.5 Do. 

Field number Pd Pt Rh Sample 

-----parts per billion-- description 

J-B235-500 (127) ..... .52 .3 <.5 Do. 

J-B235-922 (128) ..... .7 1.5 <.5 Do. 

J-X45-7 (121) ....... 2.8 2 <.5 Potassically altered 

Guichon variety. 

J-B35-956 (122) ...... <.5 <1 <.5 Do. 

Vein samples from the Bethlehem porphyry property 

J-E2-28B (140) ...... 17 14 4.1 Bornite with minor 

chalcopyrite. 

J-E2-28C (141) ...... <.5 <1 <.5 Chalcopyrite with 

minor bornite. 

respectively. For the other group, the technique has 

detection limits of 0.5, 1.0, and 0.5 ppb for palladium, 

platinum, and rhodium under optimum conditions, which 

are dependent on sample size; smaller samples have higher 

detection limits. At the 1-ppb level, precision is about ± 30 

percent for platinum, and at the 0.5-ppb level is ±20 

percent and ±50 percent for palladium and rhodium, 

respectively. Samples J-R0-40, J-X45-7, and J-E2-28B 

were analyzed for iridium and ruthenium by the method of 

Haffty and others (1980), but neither element was found 

above the limits of detection (20 ppb for iridium and 100 

ppb for ruthenium). 

The analyses in table 1 are all near or below detection 

limits for the three elements analyzed. Only one sample, 

from a bornite-rich vein (J-E2-28B), contains more than 10 

ppb each of palladium and platinum. Averages for all 

samples, excluding qualified values and the bornite-rich 

vein, are 1.06±0.54 ppb palladium, 1.63±0.44 ppb 

platinum, and 0.48±0.27 ppb rhodium. The averages for 

all samples have standard deviations less than the levels of 

precision reported for each element near the mean. 

Consequently, these low concentration levels emphasize the 

tentativeness and possibly speculative nature of the 

following discussions. 

DISCUSSION 

The calc-alkaline Guichon Creek batholith, which 

contains the Bethlehem porphyry copper deposits, was 

emplaced in an oceanic island-arc terrane. The concentration levels of platinum-group elements in rocks from the 

batholith and the deposits are low, near the limits of 

detection. The presence of small amounts of these elements 

is consistent with, and predictable from, limited data on 

their presence in other porphyry copper systems described 

earlier. The averages and standard deviations for different 

groupings of the samples are given in table 2. These 

Platinum-Group Elements-The Bethlehem Porphyry Copper Deposits F3 
A 

0 100 200 SCALE MILES 

EXPLANATION 

• Volcanic and sedimentary rocks (Tertiary) 

Volcanic and sedimentary rocks 

(Cretaceous?) 

EJ Sedimentary rocks (Jurassic) 

Intrusive rocks of the Guichon Creek batholith 

llZJ Post-Bethsaida dikes 

[2J Bethsaida phase 

[SJ Post-Skeena dikes 

E!J Skeena variety 

~ Post-Bethlehem dikes 

• Bethlehem phase 

Highland Valley phase 

• Chataway variety 

IEEJ Guichon variety 

HE Hybrid phase 

Intrusive rocks of uncertain affiliation 

Gump Lake phase 

Coyle "Granite" 

Volcanic and sedimentary rocks (Upper 

Tr'1assic) 

...... OR EtZJ Breccia bodies 

I Island-arc. volcanic rocks {Late Tnass1c 

~ and Early Jurassic) 

• 0 Porphyry copper, or copper-molybdenum 

deposit n ertlary and MesOZOIC) 

l> Alkalic porphyry copper-gold deposit 

• D Porphay~~ ~~~~~~~en urn deposit, Tert1ary 

- __ .. _Terrane boundary 

Spences 

Bridge 

t 

r 

B 

Ore deposits, important prospects 

Areas with swarms of porphyry dikes 

Fault- Dashed where inferred 

0 

SCALE~!!Iiiiiii~~~iiiiiiiiiiiiiiiiiiiiiiiiiil 

--- SCALE o.~!!'!liiiiiiiiiiii~""""""""""liiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiil16 

----- Contact- Approximately located 

Figure 1. location of the Guichon Creek batholith and the 

Bethlehem porphyry copper-molybdenum deposits in the 

southern part of the Canadian Cordillera. A, Distribution 

of porphyry deposits in petrotectonic belts, and Upper 

Triassic and lower Jurassic island-arc volcanic and related 

rocks (shaded). IB, Insular belt; CCB, Coast crystalline 

belt; 1MB, Intermontane belt; OB, Omineca belt; EMB, 

Eastern marginal belt. Modified from Christopher and 

Carter (1976), McMillan (1976), and Barr and others (1976). 

B, Geologic map of the Guichon Creek batholith showing 

the locations of samples analyzed for platinum-group 

elements, and showing the location of figure 2A. After 

McMillan (1976). Numbers refer to samples, which are 

described in table 1. 

F4 Contributions to Commodity Geology Research 
EXPLANATION 

1m Dacite porphyry (stained [J Porphyritic quartzlatite 

pmkl ~ Bethlehem granodiorite, 

• Dacite porphyry (undivided) ~ porphyry, and leucophase 

Q Granite lfij Gwchon granodionte 

~ Granodiorite -a- ~~~~=cts Dl] Breccia • Sample locality 

, , , . , Gradational contact 

Figure 2. Geology of the Bethlehem deposits showing the locations of samples analyzed for platinum-group 

elements. A, Map of the deposits. 8, Detailed map of the Jersey open pit. After Briskey and others (1981). 

Numbers refer to samples, which are described in table 1. 

groupings are based on petrologic and mineralogic characteristics of the rocks. Average PGE values for these groups 

suggest that altered and mineralized rocks are slightly 

enriched in palladium, platinum, and rhodium compared to 

relatively unaltered and unmineralized rocks. However, 

only the averages for platinum and rhodium are significantly different at the 5-percent level based on the pooled 

estimate of the standard deviations. Within the group of 

relatively unaltered and unmineralized rocks, the younger 

phases have slightly higher average platinum concentrations 

than the Bethlehem phase or Guichon variety, but the 

Guichon variety has slightly higher palladium concentrations. Neither of these comparisons are significantly different at the 5-percent level. Altered rocks have about the same 

average concentrations of platinum and perhaps rhodium in 

the propylitic, phyllic, and potassic zones. Average palladium content appears to increase from the propylitic to the 

potassic zone, but these differences are not statistically 

significant. Within the phyllic zone, the average palladium 

content is higher in altered rocks of the Guichon variety 

than in those of the Bethlehem phase, and the difference is 

significant at the 5-percent level. Highly mineralized rocks 

tend to have higher concentrations of the three platinumgroup elements. Comparison of platinum±palladium content with copper content (reported in Briskey, 1980) of the 

altered and mineralized rocks suggests that those rocks 

containing copper above about 8,000 ppm also contain 

platinum±palladium greater than 3 ppb. The average 

platinum±palladium contents of the three alteration zones 

are roughly equivalent, 2.95 to 3.09 ppb. Changes appear to 

occur in PGE concentrations during alteration and mineralPlatinum-Group Elements-The Bethlehem Porphyry Copper Deposits F5 
Table 2. Average, standard deviation, and number of 

analyses of samples containing detectable palladium, platinum, and rhodium in mineralogic and petrologic groupings of the Guichon Creek batholith and Bethlehem porphyry copper deposits 

[Unaltered rocks include major plutonic units of the Guichon Creek 

batholith, as well as weakly altered and weakly mineralized rocks from the 

Bethlehem porphyry property. Younger phases include the Skeena variety, 

Witches Brook phase, Bethsaida phase, dacite porphyry, aplite, granite, 

granodiorite, and porphyritic quartz latite. The averages for the Guichon 

variety include the analyses of Bethlehem porphyry, and the averages for 

the Guichon variety include the analyses of leucocratic Guichon variety. 

Average (x), standard deviation (rr), and number (n). -,no data] 

Group Palladium Platinum Rhodium 

X (J' n X (J' n X (J' n 

Unaltered rocks ....... 0.94 0.36 19 1.42 0.50 10 0.28 0.19 5 

Younger phases ...... .84 .24 9 1.53 .55 7 .2 - 3 

Bethlehem phase ..... .78 .33 4 <1 5 .35- 2 

Guichon variety. . . . .. 1.29 .36 4 1.25 .35 2 .6 -

Altered and mineralized 

rocks .............. 1.20 .69 16 1.77 .33 14 .68 .17 5 

Propylitic .......... .95 .23 3 2.0 - 1 <.5 - 4 

Phyllitic ........... 1.24 .62 10 1. 75 .33 8 .68 .17 5 

Bethlehem phase . . . . .79 .23 5 1.47 .06 3 .66 .19 4 

Guichon variety ..... 1.69 .56 5 1.92 .31 5 .75- 1 

Potassic ........... 1.33 1.27 3 1.76 .37 5 <.3 6 

Veins ............. 17 1 14 4.1 -

ization, but with the limited amount of data, it is not 

possible to document these changes reliably. 

Chondrite-normalized PGE ratios have been used to 

compare different groups of rocks including those from 

ophiolites, komatiites, and stratiform layered intrusions 

(Naldrett, 1981; Page and others, 1982). Generally, 

chromitites from ophiolites show negative slopes, komatiites flat slopes, and layered intrusions positive slopes. 

Figure 3 shows chondrite-normalized ratios for palladium, 

platinum, and rhodium for rocks from the Guichon Creek 

batholith and Bethlehem porphyry deposits. Bornite from 

veins has the highest ratios; relatively unaltered and unmineralized rocks, the lowest; and altered and mineralized 

rocks, intermediate ratios. Superimposed on the diagram is 

the field of ophiolitic chromitites, which represents different worldwide occurrences and ages. Komatiites and stratiform layered intrusions tend to have higher chondritenormalized ratios of palladium, platinum, and rhodium, and 

thus are not shown. Although altered and unaltered rocks 

and mineralized and unmineralized rocks from the batholith 

and the deposits have lower chondrite-normalized ratios 

than ophiolitic chrornitites, their overall negative-sloping 

character allows speculation that these patterns represent 

platinum-group elements picked up by the calc-alkaline 

magmas as they traversed through oceanic crust and islandarc volcanic lithologies, which perhaps include serpentinized ultramafic rocks of ophiolitic affinity. Nevertheless, 

the platinum-group element data are missing the iridium and 

ruthenium values necessary to define complete trends, and 

the data are too limited to firmly support such a conclusion. 

F6 Contributions to Commodity Geology Research 

w 

(.9 

a.. 

w 

!::: 

0.05 

~ 0.01 

z 

0 

::c 

~ w 

(.9 

a.. 

~ 

u 

0 

a: 

lr 

Detection Limit Ru 

~ 

Detection Limit lr 

Ru Rh Pt Pd 

ELEMENT 

Figure 3. Chondrite-normalized ratios for palladium, ~!atinurn and rhodium averages for the sample groupmgs 

defin~d in table 2 from the Guichon Creek batholith and 

the Bethlehem porphyry deposits. Field of ophiolites from 

Page and others (1985); Iron Canyon fr~m Page and others 

(1978); averages and standard dev1at1on from table 2; 

chrondite-normalizing values are the same as used by 

Page and others (1982). PGE, platinum-group element. 

Unknown mechanisms or processes in PGE metal transport 

in porphyry copper systems may be the explanation for the 

observed patterns. 

In summary, ( 1) the platinum-group elements are 

present in calc-alkaline porphyry copper systems almost at 

levels that can be investigated by the methods used; (2) 

these elements appear to show changes in concentration 

with respect to petrogenetic, alteration, and mineralization 

processes in porphyry copper systems; and (3) accumulation 

of adequate platinum-group element data from numerous 

systems may help determine source areas of metals in some 

magmatic hydrothermal copper deposits. 

REFERENCES 

Ageton, R.W., and Ryan, J.P., 1970, Platinum-group metals, in 

Mineral facts and problems: U.S. Bureau of Mines Bulletin 

650, p. 653-669. 
Barr, D.A., Fox, P.E., Northcote, K.E., and Preto, V.A., 1976, 

The alkaline suite porphyry deposits-A summary, in Sutherland Brown, A., ed., Porphyry deposits of the Canadian 

Cordillera: Canadian Institute of Mining and Metallurgy 

Special Volume 15, p. 359-367. 

Briskey, J.A., Jr., 1980, Geology, petrology, and geochemistry of 

the Jersey, East Jersey, Huestis, and Iona porphyry coppermolybdenum deposits, Highland Valley, British Columbia: 

Corvallis, Oregon, Oregon State University, Ph.D. dissertation, 399 p. 

Briskey, J.A., Jr., and Bellamy, J.R., 1976, Bethlehem Copper's 

Jersey, East Jersey, Huestis, and Iona deposits, in Sutherland 

Brown, A., ed., Porphyry deposits of the Canadian Cordillera: Canadian Institute of Mining and Metallurgy Special 

Volume 15, p. 105-119. 

Briskey, J.A., Jr., Field, C.W., and Bellamy, J.R., 1981, 

Geology, petrology, and geochemistry of the Jersey, East 

Jersey, Huestis, and Iona porphyry copper-molybdenum 

deposits, Highland Valley, British Columbia: U.S. Geological Survey Open-File Report 81-355, p. 107-126. 

Carlson, R.R., Venuti, P.E., Page, N.J, and Theodore, T.G., 

1976, Descriptions and chemical analyses of 270 rocks and 

soils analyzed for platinum-group metals from the Iron 

Canyon area, Lander County, Nevada: U.S. Geological 

Survey Open-File Report 76-524, 32 p. 

Christopher, P.A., and Carter, N.C., 1976, Metallogeny and 

metallogenic epochs for porphyry mineral deposits in the 

Canadian Cordillera, in Sutherland Brown, A., ed., Porphyry 

deposits of the Canadian Cordillera: Canadian Institute of 

Mining and Metallurgy Special Volume 15, p. 64-71. 

Eckle, E. B., 1949, Geology of the ore deposits of the La Plata 

district, Colorado: U.S. Geological Survey Professional 

Paper 219, 179 p. 

Eilers, A., 1913, Rare metals in blister copper: American Institute 

of Mining Engineers Transactions, v. 47, p. 217-218. 

Finch, R.J., Ikramuddin, M., Mutschler, F.E., and Shannon, 

S.S., Jr., 1983, Precious metals in alkaline suite porphyry 

copper systems, western North America: Geological Society 

of America Abstracts with Programs, v. 15, no. 6, p. 572. 

Haffty, Joseph, Haubert, A.W., and Page, N.J, 1980, 

Determination of iridium and ruthenium in geological 

samples by fire assay and emission spectrograph: U.S. 

Geological Survey Professional Paper 1129A-I, p. G1-G4. 

Haffty, Joseph, Riley, L.B., and Goss, W.D., 1977, A manual on 

fire assaying and determination of the noble metals in 

geological materials: U.S. Geological Survey Bulletin 1445, 

58 p. 

McMillan, W.J., 1976, Geology and genesis of the Highland 

Valley ore deposits and the Guichon Creek batholith, in 

Sutherland Brown, A., ed., Porphyry deposits of the Canadian Cordillera: Canadian Institute of Mining and Metallurgy 

Special Volume 15, p. 85-104. 

---1978, Notes and legend to accompany preliminary map no. 

30-Geology of the Guichon Creek batholith: British Columbia Ministry of Mines and Petroleum Resources, 17 p. 

Mutschler, F.E., Griffin, M.E., Stevens, S.D., and Shannon, 

S. S. , Jr. , 1984, Precious metal deposits related to alkaline 

igneous rocks in the North American Cordillera: Geological 

Society of American Abstracts with Programs, v. 16, no. 6, 

p. 606. 

Naldrett, A.J., 1981, Platinum-group element deposits, in Cabri, 

L.J., ed., Platinum group elements, mineralogy, geology, 

recovery: Canadian Institute of Mining and Metallurgy Special Volume 23, p. 197-231. 

Page, N.J, Banerji, P.K., and Haffty, Joseph, 1985, Characterization of the Sukinda and Nausahi ultramafic complexes, 

Orissa, India, by platinum-group element geochemistry: Precambrian Research, v. 30, p. 27--41. 

Page, N.J, Cassard, Daniel, and Haffty, Joseph, 1982, Palladium, 

platinum, rhodium, ruthenium, and iridium in chromitites 

from the Massif du Sud and Tiebaghi Massif, New Caledonia: Economic Geology, v. 77, no. 6, p. 1571-1577. 

Page, N.J, Myers, J.S., Haffty, Joseph, Simon, F.O., and 

Aruscavage, P.J., 1980, Platinum, palladium, and rhodium 

in the Fiskenaesset complex, southwestern Greenland: Economic Geology, v. 75, no. 6, p. 907-915. 

Page, N.J, Theodore, T.G., Venuti, P.E., and Carlson, R.R., 

1978, Implications of the petrochemistry of palladium at Iron 

Canyon, Lander County, Nevada: U.S. Geological Survey 

Journal of Research, v. 6, no. 9, p. 107-114. 

Simon, F.O., Aruscavage, P.J., and Moore, R.. 1978, Determination of platinum, palladium, and rhodium in geologic 

spectroscopy using electrothermal atomization [abs.]: American Chemical Society, National Meeting, 176th, Miami 

Beach, Florida, September 11-14, 1978. 

Smith, R.M., 1976, Mineral resources, pt. 2 of Geology and 

mineral resources of White Pine County, Nevada: Nevada 

Bureau of Mines and Geology Bulletin 85, p. 36-105. 

Theodore, T.G., Venuti, P.E., Page, N.J, and Carlson, R.R., 

1976, Maps showing distribution of palladium and other 

elements in rocks at Iron Canyon, Lander County, Nevada: 

U.S. Geological Survey Miscellaneous Field Studies Map 

MF-790, 2 sheets. 

Werle, J.L., Ikramuddin, Mohammed, and Mutschler, F.E., 

1984, Allard stock, La Plata Mountains, Colorado-An 

alkaline rock-hosted porphyry copper-precious metal deposit: 

Canadian Journal of Earth Sciences, v. 21, p. 630-641. 

Platinum-Group Elements-The Bethlehem Porphyry Copper Deposits F7 

Chapter G 

Platinum-Group ElementsOccurrences in Gold Deposits 

in Nevada, Oregon, and Idaho 

By NORMAN J PAGE, WILLIAM C. BAGBY, RAUL j. 

MADRID, and BARRY C. MORING 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract Gl 

Introduction G 1 

Geologic Setting G2 

Deposits Sampled G2 

Analytical Techniques G4 

Discussion of Results G4 

Platinum-Group-Element Occurrences and Resources G4 

Relations of Platinum-Group Elements to the Origin of the Deposit Types G6 

References Cited G7 

FIGURE 

1. Map of Nevada and adjacent parts of neighboring States showing locations of 

deposits from which rocks were analyzed for platinum, palladium, and rhodium; 

geologic host terranes; and inferred Precambrian basement G3 

TABLES 

1. Platinum and palladium analyses of rocks from hydrothermal deposits in Nevada, 

Oregon, and Idaho G5 

2. Summary of palladium and platinum analyses in rocks from five types of gold 

deposits G6 

3. Summary of palladium and platinum analyses of various rocks from carbonatehosted gold-silver deposits G6 

Contents Ill 

Platinum-Group Elements-Occurrences in Gold 

Deposits in Nevada, Oregon, and Idaho 

By Norman J Page, William C. Bagby, Raul j. Madrid, and Barry C. Moring 

Abstract 

Mineralized and unmineralized rock samples, 

selected in a reconnaissance fashion from carbonatehosted gold-silver, hot-spring gold-silver, epithermal 

gold, hot-spring mercury, and hot-spring manganesetungsten deposits in Nevada, Oregon, and Idaho are 

analyzed for platinum, palladium, and rhodium. Average 

values of platinum range from 1.6 to 23 parts per billion 

(ppb), and average values of palladium range from less 

than 1 to 4 ppb. These averages are highly biased by the 

large proportion of unmineralized rock included in the 

samples. All except hot-springs manganese-tungsten 

deposits contain detectable amounts of platinum (<1.0 

ppb) and palladium (0.5 ppb). Higher palladium contents 

tend to correlate with higher gold contents. Data are too 

sparse to speculate on the origin or genesis of the 

platinum-group elements in these deposits or to evaluate 

the possible resources in these deposit types. The range 

of concentrations of the platinum-group elements is 

remarkably limited considering the diversity of the samples analyzed. 

INTRODUCTION 

A geochemical survey of platinum-group elements 

(PGE) in Nevada, Oregon, and Idaho was initiated because 

of the reported occurrence of these metals associated with 

gold in a few widely spread and geographically significant 

hydrothermal deposits. Platinum and palladium occurrences 

have been previously recognized in placer and lode gold 

deposits from Nevada. Platinum-group elements have been 

produced from porphyry copper deposits in Nevada and 

Utah and in hydrothermal systems elsewhere (Quiring, 

1962; Mertie, 1969; Blair and others, 1977). Samples of 

placer gold from the Iron Canyon area (Theodore and 

Roberts, 1971), the Natomas placer (Theodore and Blake, 

1975), and lode gold from the east orebody of the Copper 

Canyon porphyry copper deposit (Theodore and Blake, 

1975) contained between 2 and 100 parts per million (ppm) 

palladium. Followup studies by Carlson and others (1976), 

Theodore and others (1976), and Page and others (1978) 

indicated that about half of 270 samples of rocks analyzed 

from the Iron Canyon mine area in Nevada contained 

measurable amounts of palladium that averaged 3.4 ppb. 

Other notable occurrences of platinum-group elements associated with gold include deposits in Arizona, 

British Columbia, and Brazil. In the Lost Basin-Gold Basin 

mining districts in northwestern Arizona, lode gold samples 

from the Golden Gate mine, Senator mine, and a prospect 

northwest of the Golden Hill mine contained traces of 

palladium as determined by semiquantitative spectrographic 

analyses, and a sample from the Senator mine contained 

traces of platinum (Antweiler and Campbell, 1982). Page, 

Briskey, and Mei (this volume) summarize the PGE contents in porphyry copper deposits and present PGE analyses 

for the Bethlehem porphyry copper deposits. Abundant 

palladium (as much as 2.5 metric tons, or t) along with gold 

has been produced from the Serra Pelada gold mine in 

Brazil (Engineering and Mining Journal, 1986). Some 

nuggets of gold at Serra Pelada have concentrations of as 

much as 10 percent palladium (Dayton and Sassos, 1985). 

The occurrence of platinum-group elements in the 

above deposits suggested the possibility that other gold 

deposits might also contain significant amounts of 

platinum-group elements. Based on this limited background 

of previous investigations, 65 grab samples of mineralized 

and unmineralized rocks were collected from various types 

of lode gold deposits and analyzed for platinum-group 

elements. The deposits from which the samples were 

obtained include carbonate-hosted gold-silver, hot-springs 

gold-silver, epithermal gold, hot-springs mercury, and hotsprings manganese-tungsten deposits. 

Due to the reconnaissance nature of the sampling, and 

the lack of a clear geologic context for many of the samples, 

this report should be considered preliminary. This study 

investigates the PGE resources in lode gold deposits and the 

utility of the platinum-group elements in assessing the 

genesis of the various types of gold deposits. The latter 

aspect has been discussed in Page and Talkington ( 1984) 

and may prove useful in the future when more PGE data are 

available for lode gold deposits. In this report, our purpose 

is to introduce analytical data, to discuss the significance of 

the PGE contents, and to suggest further lines of research. 

Platinum-Group Elements-Occurrences in Gold Deposits in Nevada, Oregon, and Idaho G1 
GEOLOGIC SETTING 

The deposits sampled occur in a number of diverse 

stratigraphic and structural settings of the Basin and Range 

province of the Western Cordillera (fig. 1). These settings 

are described below to illustrate their diversity ,which, it 

will be shown, appears to have had a limited effect on the 

range of PGE concentrations in rocks analyzed in this study. 

This area has been the site of repeated deformation, 

plutonism, and widespread volcanism during much of 

Phanerozoic time. 

During the Paleozioc, oceanic rocks of the Roberts 

Mountains and Golconda allochthons were emplaced over 

the continental shelf during the late Devonian Antler and 

latest Permian Sonoma orogenies, respectively (Roberts and 

others, 1958). The continental-rise and deeper water strata 

that form these allochthons were deposited in complex 

basins developed west of, and adjacent to, depositional sites 

of the continental shelf. The predominantly chertsandstone-greenstone and subordinate carbonate stratigraphy of these allochthons record sedimentologic and 

structural events that tie them to the North American craton 

(Miller and others, 1984) and, specifically, to similar events 

recorded within the coeval, largely carbonate rocks of the 

continental shelf. Thus, the Paleozoic allochthonous rocks 

in Nevada differ from rocks of similar compositions in the 

accreted terranes of the Sierra Nevada and Klamath 

Mountains, which do not display stratigraphic ties with 

rocks of the continental margin. 

These rocks in Nevada are covered by those of Upper 

Paleozoic age that composed the continental shelf and were 

deposited on the allochthons and the earlier Paleozoic 

continental shelf. These rocks, termed the Overlap 

Assemblage (Roberts and others, 1958) and the Foreland 

Basin deposits (Poole and Sandberg, 1977), occur as far 

east as western Utah and extend as far north as the Pioneer 

Mountains in Idaho. 

The early Mesozoic is characterized by the presence 

of basinal and shelf strata that discontinuously covered 

much of western Nevada and portions of north-central 

Nevada. Late Jurassic, Cretaceous, and Early Tertiary 

plutons intruded these and earlier Paleozoic rocks 

throughout the region. 

The predominance of extensional tectonics in the 

Basin and Range province developed as early as Eocene 

time but culminated during the Miocene (Stewart, 1984). 

Widespread volcanism accompanied this extensional 

tectonism in three major episodes: late Eocene to middlelate Oligocene, early to middle Miocene, and post-latemiddle Miocene. 

Isotopic studies by Kistler and Peterman (1978), 

Farmer and DePaolo ( 1983), and Kistler ( 1983) suggest that 

the Precambrian basement is present beneath the area 

studied and extends as far west as central-Nevada (fig. 1). 

G2 Contributions to Commodity Geology Research 

Overlying this basement are the Paleozoic carbonate rocks 

of the continental shelf and the allochthonous rocks. 

Paleozoic rocks are the hosts for the vast majority of 

the sediment-hosted gold-silver deposits of the region. 

Other epithermal deposit types are hosted in volcanogenic 

sedimentary and volcanic rocks or are associated with 

plutonism. 

DEPOSITS SAMPLED 

Several types . of deposits were sampled. These 

included carbonate-hosted gold-silver, hot-spring mercury, 

hot-spring gold-silver, hot-spring manganese-tungsten, and 

epithermal gold. The terminology follows that of Cox and 

Singer (1986). 

Carbonate-hosted gold-silver deposits, also known 

as sediment-hosted disseminated gold, Carlin-type, or 

invisible gold, contain assemblages of native gold± 

arsenic-bearing pyrite±barite±stibnite±realgar±orpiment 

±arsenopyrite±cinnabar±fluorite and are usually associated with silicification. These minerals, together with silica, 

selectively replace thin-bedded silty or argillaceous, and 

sometimes carbonaceous, limestone or dolostones (Bagby 

and Berger, 1985; Berger, 1985; Tooker, 1985; Madrid and 

Bagby, 1986a). Such deposits are of high tonnage 

(median= 5.1 million metric tons) and relatively low-grade 

gold compared to other types (median= 2.5 g/t) with goldto-silver ratios generally greater than 1 (Bagby, 1984; 

Bagby and Berger, 1985). The sediment-hosted gold 

deposits appear to have formed between the late Cretaceous 

and the inception of Basin and Range faulting during the 

Miocene (Madrid and Bagby, 1986b). Data suggest that 

perhaps they were formed primarily during the Oligocene, 

but more absolute dates are needed to narrowly constrain 

the episode of mineralization. Structural relations 

associated with sediment-hosted deposits indicate that 

mineralization is spatially associated with high-angle 

normal faulting. 

Hot-spring mercury deposits contain assemblages of 

cinnabar±native mercury±pyrite±minor marcasite that are 

disseminated in, and on, fractures in siliceous sinters and 

associated breccias of fossil hot-springs systems. They have 

a median tonnage of 9,500 metric tons (Rytuba, 1986). 

These deposits generally occur in Miocene and postMiocene rocks and are associated in part with volcanism. 

Gold resources that range from about 200 to over 300 

million grams (300 t) and with ore that grades 1 to 15 g/t 

gold occur in hot-spring gold-silver deposits (Tooker, 

1985). These deposits consist of assemblages of native gold 

±pyrite± stibnite ±realgar, or arsenopyrite± sphalerite± 

chalcopyrite±fluorite, or silver-selenide, or telluride± 

pyrite in crustified banded veins, stockworks, breccias, or 

disseminated in subaerial rhyolitic to andesitic ·volcanic 

centers. They are related to shallow geothermal systems 

(Berger, 1985). 
42° 

120° 118° 116° 

OREGON 

--,---·- I 

I 

e Horse Canyon 0 

~-

·. 6: 0 3 ·. \ :_ ~ 

.Alligator 

Ridge 

":\ ·. ci 

·. · ..\ .. ,' 

I · .. ·. \ 

'\, 6 ': :1 /": 

9 .. :_., :/ .r . ' ./ .· . ', ........ ) .. · I 

""'·: ....... /· I ·. ·' . I 2 ., 

114° 

I 

I 

\ 

I 

I 

\ 3 ·-~ .·~·· 

·,, 

112° 

.. 1 

I 

I" 

\i 

,o 

,>-

2 \~ 

Salt Lake City @. 

2 UTAH 

. ' \ 

. ·""~· I ------- ' .---- "' ',~~ \ I ......,_ £_.~ I 

' '~ '() J ""' ~', ' \ 

200 MILES '", \ 

~--~~~----~--~--------~ ' ' 50 

ARIZONA 

100 

50 100 200 KILOMETERS "' ',l 

Figure 1. Locations of deposits (solid circles) in 

Nevada and adjacent parts of neighboring States from 

which rocks were analyzed for platinum, palladium, 

and rhodium; geologic host terranes; and inferred 

Precambrian basement. Terranes (separated by 

dotted lines) after Silberling and others (1984) are (1) 

cratons, (2) miogeoclinal cratonal shelf, (3) Roberts 

Mountains, (4) Golconda, (5) Mesozoic overlap, (6) 

Walker Lane, (7) Jackson, (8) Black Rocks, (9) Sierra 

Nevada batholith, and (10) Idaho batholith. Shaded 

ares is postaccretion volcanic cover; dashed lines are 

0.7060 and 0.7080 initial strontium lines from Kistler 

(1983) and Farmer and DePaolo (1983), respectively. 

Platinum-Group Elements-Occurrences in Gold Deposits in Nevada, Oregon, and Idaho G3 
The term "epithermal gold deposit type" is used here 

in a broad sense to include assemblages of native gold, 

precious-metal-bearing tellurides and sulfosalts, and basemetal sulfides. These assemblages are present in vuggy 

quartz veins and breccias within zones of argillic and silicic 

alteration that are related to felsic to intermediate volcanic 

rocks. 

ANALYTICAL TECHNIQUES 

Rock samples were collected as grab samples from 

outcrops that represent ore and unmineralized rocks. The 

samples are probably not as representative of a larger mass 

as would be other types of samples, such as channel 

samples, concentrates, or tailings. Sample locations and 

descriptions are given in table 1. 

The samples were analyzed for platinum, palladium, 

and rhodium by using a fire-assay preconcentration with 

gold wire extraction (Haffty and others, 1977) followed by 

a graphite furnace atomic absorption technique (Simon and 

others, 1978; Page and others, 1980). The samples were 

analyzed in two groups. Detection limits for one group were 

0.5, 1.0, and 0.5 ppb for palladium, platinum, and 

rhodium, respectively. For the other group, detection limits 

were 1, 10, and 1 ppb for palladium, platinum, and 

rhodium, respectively. At the 1-ppb level, precision is 

about ±30 percent for platinum, and at the 0.5-ppb level, 

precision is ± 20 percent and 50 percent for palladium and 

rhodium, respectively. Samples, except those from the 

Preble deposit, were analyzed for gold, arsenic, and 

antimony by atomic absorption techniques. The method of 

O'Leary and Meier (1984) was used for gold and has a 

lower limit of detection of 0.05 ppm; modifications of 

Viets's (1978) technique were used for arsenic and 

antimony with lower limits of detection of 5 and 2 ppm, 

respectively. Mercury was analyzed by a thermally released 

mercury-gold amalgam/atomic absorption method modified 

from Vaughn and McCarthy (1964) and McNerney and 

others (1972) and has detection limits of 0.02 ppm. The 

samples from the Preble deposit were analyzed by 

quantitative emission spectroscopy with lower limits of 

detection of 0.1 or 0.2 and 1 or 2 ppm for gold and arsenic, 

antimony, and mercury, respectively. The limit of detection 

depends on how carefully the plates are read. 

Table 1 presents the results. Rhodium was detected 

only in one sample and therefore is not reported in table 1. 

Iridium and ruthenium were analyzed in samples having 

prefixes 84BM by a fire-assay spectrographic technique 

(Haffty and others, 1980) with detection limits of 20 and 

100 ppb for iridium and ruthenium, respectively. Iridium 

and ruthenium were not detected in any of the samples. 

G4 Contributions to Commodity Geology Research 

DISCUSSION OF RESULTS 

Platinum-Group-Element Occurrences and 

Resources 

During mining for gold from deposits in the area 

under consideration, samples are not commonly analyzed 

for platinum-group elements. Thus, as a resource, the 

potential for the various platinum-group elements is 

virtually unknown for the deposit types sampled for this 

report. The concentrations of palladium and platinum 

reported in table 1 for the rock samples are not high; 

however, very few of these samples represent the higher 

grade gold ores of the deposits considered. Of the 15 

samples analyzed for gold, only 4 contain gold greater than 

0.2 ppm (table 1). These four samples also contain 

palladium in the range of 2.2 to 3.8 ppb, which is high 

relative to all other samples. If higher grade ore samples are 

enriched in platinum-group elements, then the potential for 

those elements as a resource may be significant. The 

arsenic, antimony, and mercury are common trace elements 

associated with gold in carbonate-hosted gold deposits. In 

table 1, high values of palladium and platinum correspond 

to the higher values of arsenic and mercury. Although the 

number of samples is insufficient to establish statistical 

limits and constraints, the rough correspondence suggests 

that future analyses should also include rocks containing 

these gold-associated elements. 

Detailed sampling across the major gold orebodies of 

each of these deposit types will be necessary to establish 

abundances of the platinum-group elements for resource 

assessment. Table 2 summarizes the palladium and 

platinum data now available in the deposit types sampled. 

The numbers of samples with detectable concentrations of 

palladium and platinum are limited; however, they indicate 

that these elements are present in the gold and mercury 

epithermal environments. The samples from the Preble 

deposit (table 1) were collected from a wide area relative to 

the orebody. Emphasis was placed on those samples that 

displayed various degrees of hydrothermal alteration, and 

these show consistent PGE values. Table 3 summarizes 

concentration data for palladium and platinum in carbonatehosted hot-spring deposits. These data are heavily biased by 

the amount of information from the Preble deposit (table 1). 

Only a few background rock samples were analyzed for 

platinum-group elements, and they appear to display 

average PGE concentrations slightly lower than 

concentrations for the altered rocks. Therefore, a systematic 

sampling program of the unaltered host rocks of the 

orebodies should be conducted to establish threshold values 

for PGE in ore and to assess the background values of the 

host rocks. 
Table 1. Platinum and palladium analyses of rocks from hydrothermal deposits in Nevada, Oregon, and Idaho 

[Locations are shown on figure 1. Rhodium was analyzed in all samples but was not detected at 0.5 ppb except in samples as noted. Analysts: C. Gent 

for Pt, Pd, and Rh by fire assay-atomic absorption; Chris Heropoulous for Au, As, Sb, and Hg by emission spectrograph; Randy Hill for Au, As, Sb, and 

Hg by atomic absorption. *, contains 1 ppb Rh] 

Sample Location Pd (ppb) Pt (ppb) Au (ppm) As (ppm) Sb (ppm) Hg (ppm) Lithology and description 

Carbonate-hosted gold-silver deposits 

*84ARM 1 ........ Alligator Ridge 5 <1 Altered shale with disseminated 

gold. 

84ARM 2 ......... do. <1 <2 Carbonaceous shale. 

4CA001C ......... Carlin 2.2 1 Surface massive jasperoid west ore 

zone. 

CA003A .......... do. 2.0 <1 Arsenical carbonaceous ore. 

CA004B .......... do. .6 <1 Jasperoid, east wall of main pit. 

CAR830B • 0 ••••••• do. .5 <1 Limestone, fresh Roberts Mountains 

Formation. 

4CA002C ......... do. 2.8 3 Dike in northwest structure, south 

wall of main pit. 

BCB305 .......... Dee 3.2 <1 3 130 66 0.34 Silicified siltstone. 

4DE007A 0 •••••••• do. <.5 <1 Silicified, brecciated, veined siltstone. 

BC8302 ........... do. <.5 <1 .2 50 92 .48 Silicified ore-grade rock. 

4DE003A ......... do. 4.8 1 Dike, andesitic. 

19MAU83 ......... Getchell 4 <10 Carbonaceous ore. 

GEOOlB .......... do. 1.4 <1 Quartz vein in Osgood Pluton. 

GEDD4A ......... do. .6 <1 Dike, andesitic. 

OP001A .......... do. .6 <1 Fresh granodiorite. 

OPOOlA .......... do. .8 <1 Vein quartz in Osgood Pluton. 

16MAU83 ......... Pinson 5 <10 Gold ore. 

PN8302 ........... do. 3.6 1 2.9 1,800 110 80 A zone jasperoid. 

PN003B .......... do. 1.4 <1 Altered silty bed near dike. 

25MAU83 ......... Preble <10 Jasperoid breccia. 

PS1017-4 •••••••• 0 do. 1.8 1 Jasperoid with some calcite. 

4PR010C ......... do. 1 <1 <.2 40 53 <2 Jasperoid. 

4PR014D ......... do. .4 <1 Do. 

4PR024B ••••••• 0. do. 2.4 1 <.1 30 3 1.5 Do. 

4PR015D ......... do. 2.0 Do. 

4PR022B ......... do. .8 <.2 2.4 <2 <2 Limestone, unaltered. 

RM-17A .......... do. 1.6 <1 <.2 6.3 <2 <2 Limestone. 

RM-12A .......... do. 2.6 3 Dolornitized limestone. 

4PR015A ......... do. 2.2 <1 Dolomite vein. 

4PR021A ......... do. 1.1 4 <.2 25 44 <2 Carbonaceous phyllite, weakly 

altered. 

4PR016A ......... do. 1.3 <.2 2.2 <2 <2 Phyllite, unaltered 

RM 13B .......... do. 2.8 <1 Clay-altered phyllite. 

4PR014G ......... do. 2.6 <1 <.1 70 70 20 Do. 

4PR012A ......... do. 2.2 <1 1.5 70 70 20 Silicified phyllite. 

RM-15 ........... do. 1.6 <1 100 percent clay-altered phyllite. 

P-001A ........... do. 1.4 1 Stockwork quartz veins. 

4PR014E ......... do. 1.4 <1 <.1 100 10 2 Quartz vein. 

4PR012C ••••••• 0. do. 3.8 2 1 150 70 10 Do. 

4PR012N ......... do. .6 <1 <.1 30 1.5 Do. 

4PR016B .......... do. .6 <1 <.1 <1 <1 <1 Quartz vein, metamorphic. 

RM-8A ........... do. 1 <1 Quartz veins in fault zone. 

PR003A .......... do. 1.2 <1 Altered intermediate compositions 

dike. 

84BM15 .......... Horse Canyon <.5 <1 Limestone. 

84BM16 .......... do. <.5 <1 Dike rock with sulfides. 

84BM1 ........... Ten Mile <.5 <1 Altered siltstone with sulfides. 

Hot-spring gold-silver deposits 

6MAU83 .......... Delamar <1 <10 Altered porphyritic rhyolite. 

7MAU83 .......... do. <1 <10 Do. 

8MAU83 .......... do. <1 <10 Altered vitrophyre. 

12MAU83 ......... do. <1 <10 Altered porphyritic rhyolite. 

13MAU83 ......... do. <1 <10 Volcanic breccia. 

Platinum-Group Elements-Occurrences in Gold Deposits in Nevada, Oregon, and Idaho G5 
Table 1. Platinum and palladium analyses of rocks from hydrothermal deposits in Nevada, Oregon, . and 

Idaho-Continued 

Sample Location Pd (ppb) Pt (ppb) Au (ppm) As (ppm) Sb (ppm) Hg (ppm) Lithology and description 

Hot-spring gold-silver deposits-Continued 

84BM25 .......... Ivanhoe district 

84BM26 .......... do. 

84BM27 .......... do. 

84BM28 .......... do. 

2MAU83 .......... Sulfur 

<.5 

<.5 

<.5 

<.5 

<1 

<1 

<1 

<1 

<1 

23 

Mineralized tuff. 

Mineralized basalt. 

Do. 

Mineralized sinter. 

Chalcedonic sinter. 

Epithermal gold deposits 

84BM3 ........... Adelaide 

84BM4 ••••••• 0 ••• do. 

84BM5 . . .. ....... do. 

84BM22 •••• 00 •••• Marigold mine 

<.5 

2.0 

.9 

1.6 

<1 

2.0 

3.0 

<1 

Sinter. 

Altered rock . 

Dolomite . 

Mineralized veins. 

Hot spring mercury deposits 

84BM7 ........... Gold Banks 2.7 <1 Altered sedimentary rock. 

84BM8 ..... ...... do. .5 <1 Mineralized sinter . 

3MAU83 .......... McDermitt 2.0 13 Cinnabar ore. 

4MAU83 .......... do. <1 16 Tailings from retorted mercury ore. 

Hot-spring manganese-tungsten deposits 

20MAU83 ......... Golconda <1 <10 

Table 2. Summary of palladium and platinum analyses in 

rocks from five types of gold deposits 

[X=average; O"=standard deviation; n=number of samples above detection limits; n.a. =not applicable] 

Element Palladium, ppb Platinum, ppb 

deposit type x 0' n x 0' 

Carbonate-hosted Au-Ag .. 1.93 1.28 40 1.57 1.02 

Hot-spring Au-Ag ....... <1 n.a. 0 23 n.a. 

Epithermal Au .......... 1.50 n.a. 3 2.5 n.a. 

Hot-springs Hg .......... 1.73 n.a. 3 14.5 n.a. 

Hot-springs Mn-W ....... <1 n.a. 0 <10 n.a. 

Relations of Platinum-Group Elements to the 

Origin of the Deposit Types 

n 

14 

1 

2 

2 

0 

Igneous activity may serve as a source of metals, as a 

heat source for the development of ore deposits, and 

perhaps as the responsible agent for the formation of 

structures along which many deposits are formed. For most 

of the deposit types presented here, igneous activity has 

been invoked to explain the presence of the gold and 

associated elements, even though no clear links have been 

established. Certainly, there appears to be some relation 

between igneous activity and the formation of the hotspring, epithermal, and carbonate-hosted deposit types. 

There is oxygen isotopic evidence (Taylor, 1979; Radtke 

and others, 1980) that demonstrates that the waters associated with the ore stage in most epithermal and carbonatehosted deposits may have been predominantly meteoric. 

Despite this, buried plutons at depth are commonly invoked 

G6 Contributions to Commodity Geology Research 

Manganese-rich sinter. 

Table 3. Summary of palladium and platinum analyses of 

various rocks from carbonate-hosted gold-silver deposits 

[X=average; O"=standard deviation; n=number of samples above detection limit; n.a.=not applicable] 

Element Palladium, ppb Platinum, ppb 

rock type X 0' n X 0' n 

Ore ................... 4.0 1.41 4 <1 n.a. 0 

Jasperoid • 0 •••••••••••• 1.67 1.02 9 1 n.a . 5 

Quartz veins 0 •••••••••• 1.35 1.04 8 1.33 n.a. 3 

Granitic rocks and dikes .. 1.8 2.02 4 2.0 n.a. 2 

Altered and unaltered siltstones, shales, phyllites ... 2.03 .78 8 2.5 n.a. 2 

Limestone and dolomite .. 1.54 .89 5 2.0 n.a. 2 

to explain both the heat source and the source of the metals 

and fluids for all epithermal types. It is clear, however, that 

cause and effect for the source fluids is not well documented 

and that faulting alone may penetrate sufficiently hot 

reservoirs at depth, without invoking directly related plutonism. 

The depth of penetration of the faults associated with 

gold deposits in the study area is not well known, but a 

depth of 11 to 14 km may be a common penetration depth 

for most high-angle normal faults in the region. These 

depths are great enough so that tapping of rocks heated by 

the prevailing geothermal gradient is possible, particularly 

in this area where the continental crust is thin. Fluids that 

circulated within these deep fault zones may have affected 

the complete stratigraphic section. The rock types so 

affected potentially range from Precambrian basement to 
those presently exposed at the surface in the region. 

Presently, most of the large, sediment-hosted gold-silver 

deposits are hosted by Paleozoic rocks that were derived 

from, and overlie, a common Precambrian basement. 

The samples in table 1 display values that, with some 

exceptions (those for Sulfur and McDermitt), show a 

limited overall range. This result is surprising, inasmuch as 

the samples span a wide range in compositions, ages, and 

alteration and the ages of mineralization for the deposits 

span a considerable time period. Thus, this result may 

reflect a consistent overall background value for platinumgroup elements in the host rocks, a common source for the 

platinum-group elements, or common factors in the fluid 

compositions that affected the host rocks. The range in 

values may also be an artifact of the sampling without 

proper geologic context. PGE contents seem to be independent of rock type. Correlation of PGE and gold-arsenic 

contents suggests that both are dependent on the intensity of 

hydrothermal activity or on the composition of the hydrothermal fluids. 

Page and Talkington ( 1984) defined differences in the 

patterns of PGE occurrence relative to their occurrence in 

chondrite. Relative enrichments of palladium, platinum, 

and rhodium reflect their mantle source rock. This relation 

could have been used to establish sources for the platinumgroup elements found associated with the gold deposits of 

this study had the samples contained high enough PGE 

concentrations to adequately depict the necessary sourcedependent PGE patterns. 

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Antweiler, J.C., and Campbell, W.L., 1982, Implications of the 

compositions of lode and placer gold, in Theodore, T.G., 

Blair, W.N., and Nash, J.T., eds., Preliminary report on the 

geology and gold mineralization of the Gold Basin-Lost 

Basin Mining districts, Mohave County, Arizona: U.S. 

Geological Survey Open-File Report 85-1052, p. 245-263. 

Bagby, W.C., 1984, Sediment-hosted disseminated gold deposits 

in Nevada-A review of their geologic characteristics [abs.]: 

Geological Society of America Abstracts with Programs, v. 

16, no. 6, p. 434. 

Bagby, W. C. , and Berger, B. R. , 1985, Geologic characteristics 

of sediment-hosted, disseminated precious-metal deposits in 

the western United States, in Berger, B.R., and Bethke, 

P.M., eds., Geology and geochemistry of epithermal systems: Reviews in Economic Geology, Society of Economic 

Geologists, v. 2, p. 169-202. 

Berger, B.R., 1985, Geologic-geochemical features of hot-spring 

precious-metal deposits, in Tooker, E.W., ed., Geologic 

characteristics of sediment- and volcanic-hosted disseminated 

gold deposits-Search for an occurrence model: U.S. Geological Survey Bulletin 1646, p. 47-53. 

Blair, W.N., Page, N.J, and Johnson, M.G., 1977, Map and list 

of reported occurrences of platinum-group metals in the 

continental United States: U.S. Geological Survey Miscellaneous Field Studies Map MF-861, scale 1:5,000,000, 2 

sheets. 

Carlson, R.R., Venuti, P.E., Page, N.J, and Theodore, T.G., 

1976, Descriptions and chemical analyses of rocks and soils 

analyzed for platinum-group metals from the Iron Canyon 

area, Lander County, Nevada: U.S. Geological Survey OpenFile Report 76-524, 32 p. 

Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: 

U.S. Geological Survey Bulletin 1693, 379 p. 

Dayton, S.H., and Sassos, M.P., 1985, Carajas, a new district, 

new mines and a big future: Engineering and Mining Journal, 

v. 186, no. 11, p. 24-31. 

Engineering and Mining Journal, 1986, In Latin America, Brazil, 

Serra Pelada: Engineering and Mining Journal, v. 187, no. 1, 

p. 56. 

Farmer, G.L., and DePaolo, D.J., 1983, Origin of Mesozoic and 

Tertiary granite in the Western United States and implications 

for pre-Mesozoic crustal structure, pt. 1, Nd and Sr isotopic 

studies in the geocline of the northern Great Basin: Journal of 

Geophysical Research, v. 88, no. B4, p. 3379-3401. 

Haffty, Joseph, Haubert, A.W., and Page, N.J, 1980, Determination of iridium and ruthenium in geological samples by fire 

assay and emission spectrograph: U.S. Geological Survey 

Professional Paper 1129-A-I, p. Gl-G4. 

Haffty, Joseph, Riley, L.B., and Goss, W.D., 1977, A manual on 

fire assaying and determination of the noble metals in 

geological materials: U.S. Geological Survey Bulletin 1445, 

58 p. 

Kistler, R.W., 1983, Isotope geochemistry of plutons in the 

northern Great Basins, in The role of heat in the development 

of energy and mineral resources in the northern Basin and 

Range Province: Geothermal Resources Council Special 

Report, No. 13, 383 p. 

Kistler, R.W., and Peterman, Z.E., 1978, Reconstruction of 

crustal blocks of California on the basis of initial strontium 

isotopic compositions of Mesozoic granitic rocks: U.S. Geological Survey Professional Paper 1071, 17 p. 

Madrid, R.J., and Bagby, W.C., 1986a, Vein paragenesis in 

selected sediment-hosted gold deposits in north-central 

Nevada: Geological Society of America Abstracts with Programs, v. 18, no. 5, p. 393. 

---1986b, Structural alignment of sediment-hosted gold 

deposits in north-central Nevada: An example of inherited 

fabrics: Geological Society of America Abstracts with Programs, v. 18, no. 5, p. 394. 

McNerney, J.J., Buseck, P.R., and Hanson, R.C., 1972, Mercury 

detection by means of thin gold film: Science, v. 178, p. 

611-612. 

Mertie, J. B., Jr., 1969, Economic geology of the platinum metals: 

U.S. Geological Survey Professional Paper 630, 120 p. 

Miller, E.L., Holdsworth, B.K., Whiteford, W.B., and Rodgers, 

D., 1984, Stratigraphy and structure of the Schoonover 

sequence, northeastern Nevada: Implication for Paleozoic 

plate-margin tectonjcs: Geological Society of America Bulletin, v. 95, p. lO(b-1076. 

O'Leary, R.M., and Meier, A.L., 1984, Analytical methods used 

in geochemical exploration: U.S. Geological Survey Circular 

948, p. 51-55. 

Platinum-Group Elements-Occurrences in Gold Deposits in Nevada, Oregon, and Idaho G7 
Page, N.J, Myers, J.S., Haffty, Joseph, Simon, F.O., and 

Aruscavage, P.J., 1980, Platinum, palladium, and rhodium 

in the Fiskenaesset complex, southwestern Greenland: Economic Geology, v. 75, no. 6, p. 907-915. 

Page, N.J, and Talkington, R.W., 1984, Palladium, platinum, 

rhodium, ruthenium and iridium in peridotites and chromitites from ophiolite complexes in Newfoundland: Canadian 

Mineralogist, v. 22, p. 137-149. 

Page, N.J, Theodore, T.G., and Venuti, P.E., 1978, Implications 

of the petrochemistry of palladium at Iron Canyon, Lander 

County, Nevada: U.S. Geological Survey Journal of 

Research, v. 6, no. 1, p. 107-114. 

Poole, F.G., and Sandberg, C.A., 1977, Mississippian paleogeography and tectonics of the western United States, in Stewart, 

J.H., Stevens, C.H., and Fritsche, A.E., eds., Paleozoic 

Paleogeography Symposium 1: Society of Economic Paleontologists and Mineralogists, Pacific Section, Symposium 1, 

p. 67-85. 

Quiring, H., 1962, Die Metallischen Rohstoffe, ihre Lagerungsverhaltnisse und ihre wirtschaftliche Bedeutung-Platinmetalle: Stuttgart, Ferdinand Enke, v. 16, 288 p. 

Radtke, A.S., Rye, R.O., and Dickson, F.W., 1980, Geology and 

stable isotope studies of the Carlin gold deposit, Nevada: 

Economic Geology, v. 75, no. 5, p. 641-672. 

Roberts, R.J., Hotz, P.E., Gilluly, James, and Ferguson, H.G., 

1958, Paleozoic rocks of north-central Nevada: American 

Association of Petroleum Geologists Bulletin, v. 42, no. 12, 

p. 2813-2857. 

Rytuba, J.J., 1986, Descriptive model of hot-spring Hg, in Cox, 

D.P., and Singer, D.A., eds., Mineral deposit models: U.S. 

Geological Survey Bulletin 1693, p. 178. 

Silberling, N.J., Jones, D.L., Blake, M.C., Jr., and Howell, 

D. G. , 1984, Part C-Lithotectonic terrane map of the westem conterminous United States, in Silberling, N.J., and 

Jones, D.L., eds., Lithotectonic terrane maps of the North 

American Cordillera: U.S. Geological Survey Open-file 

Report 84-523, p. C1-C43. 

G8 Contributions to Commodity Geology Research 

Simon, F.O., Aruscavage, P.J., and Moore, R., 1978, Determination of platinum, palladium, and rhodium in geologic 

spectroscopy using electrothermal atomization [abs.]: American Chemical Society National Meeting, 176th, Miami 

Beach, Fla., September 11-14, 1978. 

Stewart, J.H., 1984, Geology of Nevada: Nevada Bureau of 

Mines Special Publication 4, 136 p. 

Taylor, H.P., 1979, Oxygen and hydrogen isotope relationships in 

hydrothermal mineral deposits, in Barnes, H.L., ed., 

Geochemistry of hydrothermal ore deposits: New York, 

Wiley-Interscience, p. 236-277. 

Theodore, T.G., and Blake, D.W., 1975, Geology and geochemistry of the Copper Canyon porphyry copper deposit and 

surrounding area, Lander County, Nevada: U.S. Geological 

Survey Professional Paper 798-B, 86 p. 

Theodore, T.G., and Roberts, R.J., 1971, Geochemistry and 

geology of deep drill holes at Iron Canyon, Lander County, 

Nevada, with a section on Geophysical logs of drill hole 

DDH-2 by C.J. Zablocki: U.S. Geological Survey Bulletin 

1318, 32 p. 

Theodore, T.G., Venuti, P.E., Page, N.J, and Carlson, R.R., 

1976, Maps showing geochemical distribution of palladium 

and other elements in rocks at Iron Canyon, Lander County, 

Nevada: U.S. Geological Survey Miscellaneous Field Studies 

Map MF-790. 

Tooker, E.W., ed., 1985, Geologic characteristics of sedimentand volcanic-hosted disseminated gold deposits-Search for 

an occurrence model: U.S. Geological Survey Bulletin 1646, 

150 p. 

Vaughn, W.W., and McCarthy, J.H., Jr., 1964, An instrumental 

technique for the determination of submicrogram concentrations of mercury in soils, rocks and gas, in Geological Survey 

Research 1964: U.S. Geological Survey Professional Paper 

501-D, p. D123-D127. 

Viets, J.G., 1978, Determination of silver, bismuth, cadmium, 

copper, lead, and zinc in geologic materials by atomic 

absorption spectrometry with tricaphylylmethyl ammonium 

chloride: Analytical Chemistry, v. 50, p. 1097-1101. 
Chapter H 

Sand and Gravel-An Enormous 

Offshore Resource within the 

U.S. Exclusive Economic Zone 

By S. JEFFRESS WILLIAMS 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract Hl 

Introduction Hl 

Grades and Specifications H4 

Present and Future Uses H4 

Exploration Methods and Equipment H4 

Marine Geologic Settings HS 

Atlantic Province HS 

Gulf of Mexico H6 

Caribbean Province H7 

Pacific Province H7 

Environmental Effects HS 

Conclusions H9 

References Cited H9 

FIGURES 

1, 2. Maps of the Exclusive Economic Zone: 

1. For the conterminous United States showing the occurrence of marine sand 

and gravel H2 

2. For Alaska showing the occurrence of marine sand and gravel H3 

TABLE 

1. Estimates of sand and gravel resources within the U.S. Exclusive Economic 

Zone H6 

Contents Ill 

Sand and Gravel-An Enormous Offshore Resource 

within the U.S. Exclusive Economic Zone 

By S. Jeffress Williams 

Abstract 

The U.S. Geological Survey (USGS), in collaboration 

with other Federal and State agencies and academic 

groups, is actively conducting geologic and geophysical 

studies in continental margin areas within the Exclusive 

Economic Zone (EEZ) of the United States. Some of the 

USGS projects have as objectives the location and evaluation of marine sand and gravel resources and the interpretation of the origins of the deposits. Results from these 

studies show that many extremely large deposits are 

located close to expanding metropolitan areas, which 

have a need for aggregate materials for construction, and 

near developed coastal areas, where beach replenishment 

may be used to mitigate coastal erosion. Offshore deposits are likely to be commercially mined when conventional 

deposits onshore are depleted or are no longer available 

because of land-use and environmental limitations. The 

latest estimates of onshore and offshore resources compared with the annual sand and gravel consumption in the 

United States suggest that anticipated national needs can 

be easily satisfied for the foreseeable future. 

The Nation's largest offshore sand and gravel deposits are found on the Atlantic continental margin and 

offshore Alaska, because these regions have large continental shelf areas that were affected by glacial processes 

and sea-level fluctuations that favor deposition and preservation of large sand bodies. Sand and limited volumes of 

gravel are also present on the U.S. Pacific Continental 

Shelf and on the narrow insular shelves around the 

Hawaiian Islands, Puerto Rico, and the U.S. Virgin Islands. 

Sand is also present throughout much of the Gulf of 

Mexico, but it is nearshore and tends to be fine grained 

and often mixed with muddy or organic detritus as well as 

carbonate shell material. 

INTRODUCTION 

The stability and economic well-being of the United 

States are dependent to a large degree on the mineral 

resources contained within its boundaries or available from 

reliable foreign sources. Although the Nation is self-sufficient in many minerals, much attention has focused recently 

on shortages and the uncertain supply of some strategic or 

critical minerals. 

In 1983, Presidential declaration of an Exclusive 

Economic Zone (EEZ) around the United States and its 

territories and possessions established the Nation's sovereign right to explore, conserve, and manage all resources 

within the EEZ, an area extending seaward 200 nautical 

miles around all the coasts. The EEZ proclamation more 

than doubled the national domain by adding over 3 billion 

acres (figs. 1 and 2) of submerged continental margin 

(Ballard and Bischoff, 1984) to the U.S. territorial area. 

The economically important resources identified 

within the EEZ include fisheries, oil and gas, and metallic 

and nonmetallic minerals. Recent new scientific discoveries 

of metallic minerals at deep-ocean plate boundaries in the 

Atlantic and Pacific Oceans have directed attention to the 

potential of all marine minerals. Sand and gravel, however, 

probably constitute the most widespread and immediately 

useful nonenergy mineral resource contained in offshore 

areas (Emery and Uchupi, 1984; McKelvey, 1986). 

In general, onshore sand and gravel resources are still 

plentiful across the conterminous United States, and average unit prices are less than $5 per ton; however, metropolitan areas such as Boston, New York, Los Angeles, San 

Francisco, San Juan, and Honolulu are already experiencing 

shortages in local supply and a resulting increase in cost. 

For example, prices in the New York metropolitan area can 

reach $25 per ton, and a recent U.S. Bureau of Mines 

(1987) report states that both New York City and Boston, 

Mass. , have immediate potential as markets for development of offshore mining of sand and gravel resources. 

Because transportation is a primary component in the price 

of sand and gravel, the use of marine sand and gravel is 

becoming increasingly attractive to cities having port facilities. Barge transport is often considerably less expensive 

and less disruptive than rail or truck haul, and offshore 

mining may offer land-use and environmental advantages 

over onshore mining (Williams, 1986). 

Several foreign nations such as the United Kingdom, 

the Netherlands, Denmark, and Japan already have wellestablished marine-mining industries and derive nearly 20 

percent of their sand and gravel requirements from nearshore mining. The Dutch, in particular, have a highly 

Sand and Gravel-An Enormous Offshore Resource within the U.S. Exclusive Economic Zone H1 
::I: 

N 

r'l 

0 

~ ET 

s. 

s· 

:I 

'I> 

0 

r'l 

0 

3 

3 

0 

e: 

~ 

~ 

rD 

0 

0 

CJQ 

'< 

~ 

rD 

'I> 

rD 

~ t") 

:r 

50°N 

40°N 

30°N f___ 

20°N 

\ 

\ 

130°W 

~ 

\~\ 

(1) 

..0 

'7. 

~ '0 

-'L 

00 

~ ~ 

120°W 110°W 

CANADA 

;~ 

\ I I 

MEXICO 

0 200 400 600 MILES 

0 200 400 600 KILOMETERS 

100°W 90°W 80°W 70°W 

~ 

I \ L.J ,--"'~- / 

GULF OF MEXICO 

60°W 50°W 

~/ ~ 61 0 

I 

~(; 

t 

~ ~ 

EXPLANATION 

Sand and gravel 

G) Known occurrence 

Likely occurrence 

Figure 1. Occurrence of marine sand and gravel in the Exclusive Economic Zone for the conterminous United States (modified from Williams, 1986). 
120°E 70°N 130°E 140°E 160°E 180° 160°W 140°W 120°W 100°W go ow 80°W 70°N 

I ........ \ c ........ C: Z.?' 7 7 I \ '\ " _<JiFtSJ =1_ i L j' I 0 ~ ~ 120°E 

130°E 

140°E i ARCTIC OCEAN 

U.S.S.R. 

V'l 60°N 

~~ AI 

::;, 

150°E <:_') c.. 

AI 

::;, 

c.. 

~ 

iil <...1 r Ill < rc if T 

> f( ::;, 

0 

0 

3 

I'TI 

::;, 

~ ~_./'\_____ -- A 

c 160°E fl) 

0 

::::: 

fl) 

:::r 

I ~ 0 rc 

~ -\\s.~"'v~ ~ I \ CANADA rc 

fl) 

0 

5; 50°N t') 

rc 

!- ' ~ 

:::r 

:r 

-:::r 

rc 

c: 

~ 170°E 

' I'TI t>...,.d >< ~ p.27r. t') ,.<) " c 

fl) 70 

::;:· 

rc ~ .:0 EXPLANATION I'TI 

t') 

0 Sand and gravel 00 200 400 600 MILES ::;, 

G) Known occurrence 0 

3 

;::;· ~ ~ 0 200 400 600 KILOMETERS 1 Likely occurrence 

N 

0 40°N ::;, 

rc 

Figure 2. Occurrence of marine sand and gravel in the Exclusive Economic Zone for Alaska (modified from Williams, 1986). 

:I 

t..J 
developed dredging technology to operate in the North Sea. 

Today, commercial viability of large-scale dredging worldwide appears to be restricted to water depths of less than 

approximately 40 m (Cruickshank and Hess, 1975) and 

maximum economic haul distances of approximately 150 

km, although distances can be greater depending upon the 

local factors affecting the cost of barge transport (Manheim 

and Hess, 1981; U.S. Bureau of Mines, 1987). 

The practical limit for sand and gravel resource 

assessments is the continental shelf edge, nominally at 

200-m depths. However, current dredging technology and 

economics further concentrate the focus on sand and gravel 

resources to inner shelf regions landward of about 40-m 

depths (Williams, 1986). This region will be the major 

focus of this paper. Descriptions of specific areas are based 

on resource studies completed. Other areas not mentioned 

have not been studied in sufficient detail, but future 

exploration is likely to show that they contain sizable 

resources as well. 

GRADES AND SPECIFICATIONS 

The terms "sand" and "gravel" denote grain-size 

classes of granular sediments that often occur together in the 

same deposit but in highly variable proportions due to the 

processes of formation, transport, and deposition. Both 

sand and gravel are composed of diverse rock types; 

however, the major constituent is quartz, with secondary 

amounts of feldspar, iron oxides, and heavy minerals. 

According to the widely used Udden-Wentworth classification, sand is material between 0.63 and 2 mm (4 to -1 phi 

units), retained on a No. 230 sieve. Gravel is material in the 

range of 2 mm to 64 mm. Sand and gravel used as aggregate 

in concrete for construction and road building often have 

very specific grain size, sorting, shape, and chemical 

characteristics (Tepordei, 1987). 

Selection of sand used as fill for beach replenishment 

and restoration is dependent upon the physical properties of 

the native beach sediments and on the intended use of the 

beach after fill operations are completed (Duane, 1969). 

Ideally, the borrow material should be similar in grain size, 

sorting, and composition to the native sediments. Matching 

the composition of the native beach with borrow sand is also 

important. Sands having a large proportion of calcium 

carbonate fragments are likely to be broken and abraded 

relatively quickly if placed on high-energy quartz beaches. 

PRESENT AND FUTURE USES 

Prior to the buildup of metropolitan areas and the 

construction of concrete road systems, demand for sand and 

gravel was limited, and mining and production were small. 

However, steadily increasing requirements for large volumes have made sand and gravel the third largest (behind 

H4 Contributions to Commodity Geology Research 

cement and crushed stone) U.S. nonfuel mineral industry. 

The most recent ( 1986) U.S. production figures from 

Tepordei (1987) show that domestic production of construction sand and gravel was 837 million short tons, valued at 

$2.6 billion. Production of industrial sand and gravel for 

1986 totaled 28.5 million tons, valued at $360 million. In 

terms of marine minerals, even though construction sand 

and gravel have a low unit price (average $3.20 per ton, 

Tepordei, 1987), they are the second most valuable marine 

mineral (behind oil and gas) mined at the seabed (Emery 

and Uchupi, 1984; McKelvey, 1986). 

Most sand and gravel production is from onshore 

sources and is intended primarily for construction, mainly 

as aggregate in concrete and as road-base material and earth 

fill. Lesser amounts are utilized in specialty applications 

such as glass making, as foundry sand for metal casting, 

and by the abrasives industry. In Alaska, sand and gravel 

from onshore and offshore are used to construct islands on 

which to locate facilities associated with exploration and 

recovery of hydrocarbons. The islands, which are built in 

nearshore areas in water depths not exceeding 20 m, enable 

year-round drilling. To date, approximately 10 million 

cubic meters of sand and gravel have been mined in the 

North Slope region for island construction (Molnia, 1979). 

Since the early 1950's, use of sand as fill to replenish 

eroded beaches has become more widespread, both to 

enhance the recreational assets and to lessen storm damage 

due to waves and storm-surge flooding (Duane, 1969). 

More than 40 beach restoration projects in the United States 

have been completed. The Federal projects alone used more 

than 59 million m3 of sand fill. For environmental reasons 

and to obtain sand of optimum texture at the lowest cost, 

marine or estuarine sources have been used in most nourishment projects. 

Recent scientific evidence suggests that sea level 

around the world could rise 70 em in the next 100 years due 

to climate warming brought on by the buildup of atmospheric carbon dioxide and other gases released as a 

consequence of human activities (Revelle, 1983). Natural 

sea-level rise, which has averaged 15 to 20 em over the past 

century, is a primary factor in coastal erosion; consequently, these forecasts of accelerated rise for the near 

future are reason for concern. In coastal areas where 

engineering solutions are deemed economically feasible, 

construction of protective beaches and dikes is going to 

require many millions of tons of fill material. Offshore 

areas may be a logical source of such large volumes of sand 

and gravel. 

EXPLORATION METHODS AND EQUIPMENT 

The procedures for locating and assessing sand and 

gravel on the seabed generally begin with high-resolution 

seismic-reflection profiling by use of equipment towed from 
survey vessels. Seismic analog records are formed by echos 

from subbottom strata and are similar to geologic cross 

sections. These records are useful in determining the 

subbottom stratigraphy and structure and for mapping 

buried features such as fluvial and tidal-inlet channels. 

Another tool, high-resolution sidescan sonar equipment, 

focuses a broad acoustic beam across a swath of seabed to 

define the small-scale relief (shoals, bedforms) and variations in seabed texture. The latest of these automated 

systems include computer-assisted recorders that adjust for 

the slant-range distortion. These data can be used to 

produce photolike images of the seabed when sonograms 

from parallel ship tracks are fit into a mosaic (Williams, 

1982). 

Grab samples of sea-floor sediment are useful in 

confirming interpretations from seismic and sidescan sonar 

data regarding sediment composition and are helpful in 

identifying promising sites worthy of deeper sampling by 

cores. Vibratory coring equipment (pneumatic, hydraulic, 

and electric) is relatively inexpensive to operate and has 

been used successfully since the early 1960's for recovering 

long and relatively undisturbed cores of granular sediment. 

Pneumatic vibracores are limited to water depths of about 

100 m, but hydraulic and electric vibracores are more 

versatile for deep-water sampling and can operate to at least 

shelf-edge depths (200 m). Cores as long as 6 m are 

routinely taken, and recovery of 10 to 12m of sediment can 

be accomplished by using water-jetting techniques with the 

vibracore (Meisburger and Williams, 1981). 

A variety of electronic positioning equipment is 

available to accurately determine the horizontal location of 

bottom and subbottom features detected during the geophysical and sediment-sampling surveys. Microwave systems are desirable for nearshore surveys because of their 

high (±3m) accuracy. For longer range surveys, LORANe is widely used, and automated and very accurate global 

positioning systems are becoming more widely available. 

MARINE GEOLOGIC SETTINGS 

The occurrence, sedimentary character, and distribution of sand and gravel on the continental shelves are the 

result of a combination of glaciofluvial, marine, and estuarine processes that affected the continental shelves many 

times during Pleistocene and Holocene times, periods 

spanning the past 1. 6 million years (Field and Duane, 

1976). The following factors from Williams (1986) are 

major influences on the geologic framework and geomorphologic character of the U.S. continental margin: ( 1) Four 

or more major glacial advances in northern latitudes of the 

Atlantic and Pacific regions transported massive volumes of 

sediment from continental areas to coastal plain regions, 

parts of which are now submerged continental shelves. (2) 

Growth and decay of continental glaciers due to climate 

change and isostatic adjustments due to glacial loading and 

unloading have caused worldwide and local fluctuations in 

sea level in the range of 100 to 150 m. These fluctuations 

caused repeated transgressions and regressions of the coast 

across the shelves. (3) Meltwater-enlarged streams and 

rivers drained glacial terrains and transported large volumes 

of terrestrial sediment onto exposed shelf areas during 

Pleistocene sea level lowstands. (4) Tectonic changes, 

especially along the U.S. Pacific margin, altered land 

elevations, which affected the gradients of streams and their 

capacity to transport sediments to the coast and onto the 

shelf. 

Atlantic Province 

On the U.S. Atlantic continental margin, the EEZ 

encompasses very large continental shelf areas as well as 

portions of the slope and rise (fig. 1). The northern region 

from Maine to Long Island, N.Y., experienced at least four 

glacial advances and associated marine transgressions during the Quaternary period. Numerous geologic studies 

(Schlee and Pratt, 1970; Trumbull, 1972; Schlee, 1973) 

show that thick sequences of glaciofluvial outwash sand and 

gravel deposits are present throughout much of the region, 

resulting in enormous resources estimates (Manheim, 

1972). Although sand and gravel may be plentiful, the 

deposits are likely to vary considerably in textural properties, and muddy sediments are occasionally mixed with or 

overlie sand and gravel deposits (Schlee, 1973). 

Gravel is most abundant north of lat 40° N. To the 

south, gravel distribution is patchy and limited to areas 

where exposed ancestral river channels and deltas are 

subject to marine erosion and winnowing processes. The 

most promising sand and gravel deposits are associated with 

glacial depositional features such as moraines, outwash 

plains, and glaciofluvial deltas (Duane and Stubblefield, 

1986). Several moraines and deltas offshore Maine and 

Massachusetts are described by Oldale and others (1983) 

and Oldale ( 1985). High-quality aggregate associated with 

such glacial landforms has been identified around Massachusetts Bay (Schlee and others, 1973) and Nantucket. 

Identified resources of offshore sand and gravel (table 1) 

appear sufficient to supply the New England market well 

into the future (Manheim and Hess, 1981). 

The New York City metropolitan area is one of the 

major markets for sand and gravel in the United States. 

Large sand and gravel deposits on the inner shelf and along 

the south shore of Long Island (Williams and Duane, 197 4; 

Schlee and Sanko, 1975) and in more restricted areas of 

Long Island Sound (Williams, 1981) have great potential 

for use as commercial aggregate and as sand fill to replenish 

the eroded coast along the south shore of Long Island 

(Williams, 1976). Offshore resources are judged to be in 

excess of 10 billion m3 (Williams, 1976), enough to meet 

Sand and Gravel-An Enormous Offshore Resource within the U.S. Exclusive Economic Zone H5 
Table 1. Estimates of sand and gravel resources within 

the U.S. Exclusive Economic Zone 

[Modified from Williams,1986] 

Province 

Atlantic 

Volume 

(cubic meters) 

Maine-Long Island . . . . . . . . . . . . . . . . . . . . . . . . . . . 340 billion 

New Jersey-South Carolina........ . . . . . . . . . . . . . 190 billion 

South Carolina-Florida . . . . . . . . . . . . . . . . . . . . . . . . 220 billion 

Gulf of Mexico . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 billion 

Caribbean .................................... . 

Virgin Islands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 million 

Puerto Rico . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 million 

Pacific 

Southern California . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 billion 

Northern California-Washington.... . . . . . . . . . . . . . Insufficient data 

Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 billion 

Hawaii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 billion 

the needs of Metropolitan New York for many centuries at 

current consumption rates. The middle Atlantic Shelf 

region, from New Jersey to South Carolina, is south of the 

direct influence of Pleistocene glaciation, but the area 

received large volumes of clastic terrigenous sediment when 

sea level was lower and the ancestral Delaware, Susquehanna, Potomac, and Roanoke Rivers had much larger 

sediment discharges than do their present-day counterparts. 

The largest sand deposits are present in the relict deltas, 

located where the rivers intersected paleoshorelines, and in 

the filled fluvial channels that transect the shelf. The many 

prominent capes along the coast are regions of abundant 

sand supply as well, and their associated shoals are promising sites for future exploration. 

Linear shoals are common sea-floor features, particularly on the continental shelf off New Jersey and the 

Delmarva Peninsula. The shoals, which are as much as 10 

m thick and hundreds of meters wide, extend for tens of 

kilometers (Duane and others, 1972). Seismic profiles and 

cores show most of these shoals are composed of clean 

medium-to-coarse sand, texturally similar to the onshore 

beaches they abut (Field, 1980). Some of the shoals may 

represent relict barrier spits and islands drowned in place by 

the late Holocene transgression~ however, geologic evidence suggests the majority formed in the nearshore region 

by coastal hydraulic processes reworking existing sand 

bodies, such as relict deltas and ebb-tide shoals. With 

sea-level rise, the coast migrates landward, and the shoals 

become detached from the shoreface (Field and Duane, 

1976). 

Individual shoals, many containing millions of cubic 

meters of sand, appear to be highly suitable borrow sources 

for beach-fill projects. At present, several linear shoals 

offshore Maryland are being evaluated as sand sources for 

replenishment of the beaches at Ocean City, Md. (Kerhin 

and Williams, 1987). With regard to the sand budget of the 

adjacent coast, the environmental effects of dredging the 

H6 Contributions to Commodity Geology Research 

shoals are cause for concern, but these effects can be 

minimized if sand is removed from several shoals that are 

well seaward of the zone of active littoral processes. 

Even though more information is available for estimating sand and gravel resources along the Atlantic EEZ 

than for anywhere else, these resource estimates vary 

greatly depending upon the assumptions made and the 

degree of extrapolation from limited, often widely spaced 

data. Manheim and Hess (1981) have estimated as much as 

830 billion m3 of sand and gravel are present on the shelf 

based on average thicknesses of 5 m. Current scientific 

knowledge, however, suggests that the sedimentologic 

character of the shelf is much more complex. Gravel is 

limited and patchy in distribution, and sand is widespread, 

but the greatest thicknesses are found in discrete bodies. 

North of lat 40° N. , thicknesses of sand and gravel may 

exceed 5 m~ however, this thickness is too optimistic an 

average for other areas. Probably the most reliable estimate 

of sand and gravel for the Atlantic shelf is 750 billion m3 

(table 1), but this estimate is likely to increase when 

additional areas are surveyed. Estimates will be further 

refined as the U.S. Geological Survey and several State 

Geological Surveys, including those in Maine, Connecticut, 

Maryland, Virginia, Florida, and Louisiana, complete 

cooperative studies aimed at evaluating sand and gravel 

deposits within their respective territorial waters. 

Gulf of Mexico 

The Gulf of Mexico Continental Shelf from the 

Florida peninsula to the Mexico border is an enormous area 

in which little attention has been focused on sand and gravel 

resources (fig. 1). Like the Atlantic Shelf, the Gulf of 

Mexico Shelf owes most of its geomorphological character 

and shallow sedimentary stratigraphy to Quaternary sealevel fluctuations and the resulting transgressions and 

regressions of the coast. In the central Gulf of Mexico, the 

Mississippi River has been a dominant influence on the 

composition and distribution of clastic sediments. Ancestral 

channels of the Mississippi River have shifted position over 

time, each channel building large deltaic complexes that are 

fronted by sandy barrier islands. When the channels change 

position, the coastal barriers and abandoned deltas erode 

and migrate landward, leaving blanket-type sand deposits 

and linear shoals having relief of 5 to 10 m (Berryhill and 

others, 1985). Among those off Louisiana are the Chandeleur Islands and their associated sand sheet, the Isles 

Dernieres and associated Ship and Outer Shoals, and Trinity 

and Tiger Shoals. 

Over the past 8 years, the Louisiana Geological 

Survey has cooperated with the U.S. Geological Survey to 

carry out geophysical and coring surveys over parts of the 

Louisiana Shelf to identify and map the geometry of sand 

bodies. Plans are now underway by the State to use offshore 
sand to nourish three different coastal areas to test the 

effectiveness of constructing beach fills to mitigate the 

serious erosion and land-loss problems in coastal Louisiana. 

Surveys of limited extent in Florida, Louisiana, and 

Texas, aimed at mapping and characterizing nearshore sand 

bodies for beach nourishment, have been conducted by the 

U.S. Army Corps of Engineers over the past decade. These 

surveys have focused on nearshore areas of St. Petersburg 

and Panama City, Fla., Grand Isle, La., and Galveston and 

Corpus Christi, Tex. All but the Galveston coast have been 

nourished in the decade. Williams and others (1979) identified five potential sites offshore Galveston where relict 

channels and deltas contain an estimated 63 million m3 of 

mostly muddy fine sand, but so far no dredging of material 

for use in beach replenishment has taken place. 

Caribbean Province 

Exclusive Economic Zones have also been established for the U.S. Virgin Islands and Puerto Rico. The 

Virgin Islands and Puerto Rico are part of a volcanic 

island-arc complex exhibiting narrow insular shelves and 

abrupt shelf breaks at about 100 m below sea level. 

Terriginous sediments are most abundant close to shore, 

where modem and ancient rivers deposited marine deltas. 

The sediments, which exhibit a reduction in grain size, 

become mixed with carbonate and organic material away 

from the river mouths. Both Puerto Rico and the Virgin 

Islands are experiencing severe shortages of sand and gravel 

for concrete aggregate as well as sand of suitable texture for 

replenishment of eroded beaches. In some areas, onshore 

sources of sand are so limited that the beaches and dunes 

have been mined. These practices occurred for many years 

until recently and have altered the esthetic beauty and 

natural protection of the beach and have aggravated coastal 

erosion. 

In the early 1970's, the beaches of the Virgin Islands 

were recognized as a valuable natural resource that attracted 

tourists, and mining along the coast was prohibited. Until 

1977, except for illegal sand extraction from the beaches at 

night, the Virgin Islands' primary sand source was Puerto 

Rico, where sand from river channels and deltas was mined 

and shipped at a cost of approximately $16Im3 (Hubbard 

and others, 1981). This practice was halted by the Commonwealth when the rivers were recognized as the source 

for most of the sand on the coast. Once the environmental 

effects of mining the shore and onland sites were known, 

both countries began to investigate the feasibility of mining 

offshore sand bodies. 

In the late 1970s, the U.S. Geological Survey conducted surveys to inventory sand on the insular shelves of 

the U.S. Virgin Islands. Holmes (1978) reports several 

promising sand prospects and estimated that one sand body 

off the southwest coast of St. Thomas contains 30 million 

m3 of fine sand, and another, a shoal near Buck Island, is 

calculated to contain 12 million m3 of sand. Recent surveys 

offshore St. Croix have identified two major sand bodies on 

the broad southern shelf (table 1). A site on its eastern shelf 

contains almost 4 million m3

. Seismic-reflection data suggest that sand thicknesses of 17 m are present over a broad 

area west of Sand Point (Hubbard and others, 1981); 

however, long sediment cores are needed in conjunction 

with the seismic profiles in order to estimate actual sand 

volumes. 

The narrow shelves on all these islands lack large 

sand bodies, apparently because the dominant coastal processes transport sand offshore into the deeper basins. These 

processes are aided by several submarine canyons that 

funnel sand seaward into deep water. Additional seismic 

and coring surveys are necessary before potential deposits 

can be evaluated in other parts of the U.S. Virgin Islands. 

Areas with naturally high biogenic sand productivity may 

be especially promising for mining, although no studies 

have been done to determine rates of production of carbonate sands. 

Puerto Rico requires about 7 million m3 of construction sand in addition to the large volumes of fill needed to 

mitigate beach erosion. Present onshore supplies are very 

limited. Cooperative efforts by the U.S. Geological Survey 

and the Department of Natural Resources of Puerto Rico 

over the past decade have identified three offshore sand 

bodies in water depths shallower than 16 m (Grove and 

Trumbull, 1978, and Rodriguez, 1984). The best prospects 

are off Cabo Rojo on the southwest coast and at the Escollo 

de Arenas deposit. Their total volume of 170 million m3 

could supply the anticipated need of Puerto Rico for over 

two decades. Present field surveys are directed at studying 

the broad insular shelf off eastern Puerto Rico, and preliminary results indicate a high potential for additional large 

volumes of sand (Rodriguez, 1984). 

Pacific Province 

The major commercial requirements for sand and 

gravel in the U.S. Pacific region are in southern California 

for construction aggregate and fill for beach nourishment; in 

Alaska, to serve in construction of manmade islands for 

hydrocarbon exploration and production; and in Hawaii, 

where shortages are such that local prices for constructionquality sand reach $501m3 (Ballard and Bischoff, 1984). 

The tectonically active U.S. Pacific margin has a 

comparatively narrow continental shelf, limiting the deposits recoverable by present dredge technology. The narrowness of the shelf and its unrestricted exposure to Pacific 

storms result in much larger waves than on the Atlantic or 

Gulf of Mexico coasts, thereby constricting the periods 

during which dredges can operate safely. 

Sand and Gravel-An Enormous Offshore Resource within the U.S. Exclusive Economic Zone H7 
Geophysical and coring surveys off southern California, summarized by California Department of Boating and 

Waterways (1983), show that sand, generally fine-grained, 

and some gravel are present in narrow zones parallel to the 

coast. Most sand and gravel occur as relict blanket, deltaic, 

and stream-valley fill deposits in the offshore extensions of 

some major rivers. Large and economically significant 

deposits are present on the shelf off San Diego, San Pedro, 

and Santa Monica (fig. 1). Some of these deposits are of 

limited extent and occur in basins bounded by bedrock 

cropping out at the seabed, whereas other deposits are of 

currently marginal value because of muddy overburden 

sediments several meters thick. Various studies have 

yielded estimates of 30 billion m3 of sand and gravel 

resources for southern California. However, only about 10 

billion m3 are located within depths of 30 m below sea 

level, and some of the deposits may be too fine for use as 

either beach fill or construction sand (California Department of Boating and Waterways, 1983). 

The distribution of surficial sediments at the seabed 

for the rest of the California, Oregon, and Washington Shelf 

is known only to a limited degree, but even less information 

is available on the shallow stratigraphy and sedimentary 

character. Preliminary work indicates several high-potential 

deposits are present off central Washington, proximal to 

markets in Portland, Oreg., and Seattle, Wash. Oregon has 

recently released a map of the EEZ of its coast that includes 

resource information on sand, gravel, and other commodities (Gray and Kulm, 1985). 

The U.S. Geological Survey has studied the geologic 

character and modem processes of much of Alaska's coasts 

and shelves. Many of these efforts have been summarized 

by Peter Stauffer (written commun., 1986), who describes 

the occurrence, distribution, and estimated volumes of sand 

and gravel on the Alaska Shelf (fig. 2). Sediments there are 

highly variable because of Alaska's complex geologic 

history and the dominant influence of seasonal ice and 

glacial erosion and deposition. Gravel is abundant in many 

regions. The largest sand and gravel deposits are contained 

in moraines at the coast or on the seabed where waves and 

currents have winnowed and removed the fine-grained 

sediment, leaving a coarse lag deposit (Molnia, 1979). 

Many of the barrier islands and spits in Alaska 

contain large volumes of gravel, but most are now cut off 

from their sediment sources. Mining could harm sensitive 

areas and increase coastal erosion. Also, many of the 

offshore areas of Alaska exhibit complex topography that 

includes deltas and fields of sand ridges containing large 

volumes of sand. Peter Stauffer (written commun., 1986) 

reports the Yukon River delta and associated sand bodies 

alone contain an estimated 70 billion m3 . Buried stream 

channels in nearshore shelf areas also contain large volumes 

of coarse sand. The effects of mining these deposits may 

come closest to duplicating the natural process where sea 

ice gouges troughs or furrows in the seabed that are 

H8 Contributions to Commodity Geology Research 

subsequently filled by shelf sediments. If Alaska's construction growth and oil exploration continue, demand for 

sand and gravel is likely to be high. And while onshore 

resources are large and widespread, the high transportation 

costs and lack of roads may favor offshore mining to meet 

future commercial demands. 

Many parts of the Hawaiian Islands suffer severe 

shortages of suitable sand and gravel for reasons similar to 

those in the U.S. Virgin Islands and Puerto Rico. Demand 

is great for construction-quality aggregate, and beach nourishment is a method preferred by the State for mitigating 

erosion of the recreational beaches that are so important to 

the economy of Hawaii (Dollar, 1979). Sand from onshore 

pits can cost $501m3 , but some of the islands do not have 

enough sand to meet demands at any price. The offshore 

areas may offer a logical alternative. Several geophysical 

and sediment sampling surveys have identified pockets of 

sand along the narrow insular shelves (Moberly and others, 

197 5). Much of the material is a mixture of volcanic detritus 

and calcareous sand; the most promising deposits are relict 

Pleistocene shore terraces, drowned by the Holocene transgression. One such source area is off Penguin Bank, 35 km 

from Honolulu in 50-m to 60-m water depths. It contains an 

estimated 270 million m3 of sand (Campbell and others, 

1970). Other such banks and buried ancestral stream valleys 

containing potentially valuable sand may exist offshore. 

Additional site-specific studies to locate and evaluate these 

features will help in assessing Hawaii's sand resources. 

ENVIRONMENTAL EFFECTS 

Environmental concerns have been a major deterent 

to implementation of marine mining in the United States, 

even when suitable deposits are present and where the 

economic factors are favorable. A number of the environmental studies carried out over the past decade and summarized by N aqui and Pullen (1982) show that the impact of 

dredging depends largely on the local geologic and biologic 

conditions. Dredging effects are most detrimental where 

proportions of fine-grained sediment are high and where the 

dredging is close to nonmobile benthic communities, 

because the muds can reduce light transmission and smother 

organisms. This situation could be a problem in reef areas 

of southern Florida and for many of the islands in the 

Caribbean and Pacific. 

Dredging can also affect the environment by exposing 

a different substrate or by causing substantial changes in the 

seabed topography from removal of large volumes of sand. 

Dredging in areas with mobile fauna produces no apparent 

long-term ill effects, and in cases where sediment elutriation releases organics into the water column, the effects 

actually may be beneficial. Most long-term environmental 

damages can be avoided by careful planning prior to 

dredging, by the use of proper dredging equipment, and by 
close monitoring of the dredge site and adjacent areas 

during the operation (Naqui and Pullen, 1982). 

Dredging too close to coastal areas is likely to remove 

sand from the active sediment budget and alter wave and 

current patterns, changes that can eventually increase erosion. The volume of sand along the coast and the morphology of nearshore areas are influenced by wave and current 

conditions. If sand is dredged too close to shore, the shore 

profile will shift as sand moves seaward from the shore to 

fill the dredge holes. These problems can be avoided if 

dredging is limited to relict sand bodies, which are no 

longer connected to littoral processes, or to areas where 

natural sediment input is great enough to compensate for 

losses due to dredging. These safeguards may require 

dredging farther offshore, which will increase costs, but the 

alternatives will accelerate coastal erosion and property 

damage and may ultimately be far more costly. 

CONCLUSIONS 

Sand and gravel deposits are abundant and widespread resources within much of the U.S. Exclusive Economic Zone. Their volume and proximity to market areas 

make them potentially the most valuable and immediately 

useful nonenergy commodity within U.S. offshore areas. 

Some deposits are already competitive with onshore deposits for uses such as beach replenishment and manmade 

island construction. Other deposits could be competitive 

within the next decade, especially near urban areas such as 

Boston, New York, Los Angeles, San Juan, and Honolulu, 

where nearby onshore deposits are depleted or where land 

use and environmental laws constrain mining. Dredging 

technology is now available for the mining of sand and 

gravel in water depths to 40 m with little long-term 

environmental harm, and private industry appears willing to 

pursue marine mining if suitable leasing provisions are 

established by Federal and State governments. 

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---1981 , Sand resources and geological character of Long 

Island sound: Coastal Engineering Research Center, Technical Paper 81-3, 65 p. 

---1982, Use of high resolution seismic reflection and sidescan sonar equipment for offshore surveys: Coastal Engineering Research Center, Technical Aid 82-15, 22 p. 

---1986, Sand and gravel deposits within the United States 

Exclusive Economic Zone-Resource assessment and uses: 

Offshore Technology Conference, 18th Proceedings, p. 

377-386. 

Williams, S.J., and Duane, D.B., 1974, Geomorphology and 

sediments of the inner New York Bight Continental Shelf: 

Coastal Engineering Research Center, Technical Memorandum No. 45, 83 p. 

Williams, S.J., Prins, D.A., and Meisburger, E.P., 1979, Sediment distribution, sand resources, and geologic character of 

the inner continental shelf off Galveston County, Texas: 

Coastal Engineering Research Center, Miscellaneous Report 

79--4, 159 p. 
Chapter I 

Tungsten-Geology and Resources of 

Deposits in Southeastern China 

By JAMES E. ELLIOTI 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract 11 

Introduction 11 

Geologic Settings of Tungsten Deposits 12 

Tectonics and Structure 12 

Association with Granitoid Rocks 12 

Description of Deposits 12 

Shizhuyuan Mine 15 

Xihuashan Mine 16 

Piaotang Mine 16 

Dajishan Mine 17 

Production and Resources 17 

Summary 18 

References 19 

FIGURES 

1. Map showing locations of major tungsten mines and districts in southeastern 

China 13 

2. Generalized cross section through the Shizhuyuan deposit 15 

3. Generalized longitudinal section through the Xihuashan and Piaotang tungsten 

deposits in the Dayu district 16 

4. Generalized cross section through the Dajishan mine area 18 

TABLE 

1. Deposit types, lithologies, and ages of host and associated igneous rocks and the 

references for mines and districts shown in figure 1 I4 

Contents Ill 

Tungsten-Geology and Resources of Deposits in 

Southeastern China 

By James E. Elliott 

Abstract 

The People's Republic of China is the largest producer of tungsten in the world with an annual production 

of about 15,000 metric tons of contained tungsten, approximately a third of the world's total production. In addition, 

it is estimated that more than 40 percent of world's 

tungsten reserves are in China. Nearly all of China's 

tungsten deposits are located in the southeastern part of 

the country, a region that was a complex continental 

margin from Middle Proterozoic to at least Late Cretaceous time. The complex geology is the result of sedimentation that was interrupted by several periods of folding, 

faulting, metamorphism, and igneous activity. 

Most of China's tungsten production comes from 

wolframite-bearing quartz-vein systems such as those at 

the Xihuashan and Dajishan mines; these mines have 

operated since the early 1900's. During the last 35 years, 

important skarn deposits have also been discovered; 

these include the Shizhuyuan W-Sn-Mo-Bi deposit, the 

largest tungsten deposit in the world. Other important 

kinds of deposits include disseminated, stockwork or 

porphyry, greisen, and strata-bound. Most of the deposits 

have complex mineralogy, and most mines produce a 

variety of byproducts in addition to tungsten. The most 

common of these are tin, molybdenum, and bismuth. 

Other commodities such as copper, lead, zinc, niobium, 

tantalum, beryllium, and rare earth elements are also 

important. 

Nearly all of the tungsten deposits are closely related 

to highly evolved, felsic, high-silica granites of Jurassic or 

Cretaceous age. These probably formed by anatexis of 

continental crust, which was made up of metasedimentary 

and older felsic igneous rocks that were enriched in 

tungsten and associated metals. The partial melting of 

continental crust and the generation of granitic magmas 

occurred as a result of westward-directed subduction 

during the middle and late Mesozoic. 

INTRODUCTION 

Since the early 1900's, when tungsten first became 

important to the industrial countries in North America and 

Europe, China has been a major supplier of this strategic 

commodity to world markets. At present, China continues 

to dominate the tungsten market as the world's leading 

producer of tungsten, accounting for approximately onethird of the world's production in 1985. Until about 1949, 

most of the tungsten production was from small mines 

worked by local villagers and farmers by hand with little 

mechanization. Most of these workings were on surface 

outcrops of veins and in shallow underground workings 

along the veins. Since the founding of the People's Republic of China in 1949, the explorati<Dn, development, and 

mining of tungsten have been organized and directed by 

government agencies. Many districts having numerous 

small mines were consolidated and developed as large 

mechanized tungsten mines with centralized milling facilities. In addition, systematic exploration since about 1960 

has resulted in the discovery of many new deposits, several 

of which have not yet reached full production status. 

Until recently, information on the geology and 

resources of tungsten in China was very sparse and fragmentary. Prior to about 1982, the few geologic reports 

available were generally based on information obtained 

prior to 1949. Since 1982, however, there has been a rapid 

increase in the knowledge of the geology and mineral 

resources of China as a result of visit$ by western geologists 

to China, the publication of Chinese-authored reports in 

English, and international conferences and symposia held in 

China. Nevertheless, information on tungsten mines and 

deposits is still very limited because many aspects of the 

geology, production, reserves, and even accurate locations 

of deposits are still considered to be confidential by Chinese 

government agencies. Some of the most valuable and 

accurate data on the resources and $eology of tungsten in 

China are the result of personal visits to important mines 

and districts by western geologists. 

During 1984 several U.S. Geological Survey (USGS) 

geologists participated in an exchange with geologists from 

the Chinese Academy of Geological, Sciences. Part of this 

exchange consisted of visits to major tungsten mines and 

districts in China by three of the USGS geologists. The 

major deposits visited included the Shizhuyuan deposit in 

the Dongpo ore field, Hunan province; the Xihuashan and 

Tungsten-Geology and Resources of Deposits in Southeastern China 11 
Piaotang mines in the Dayu district, Jiangxi province; and 

the Dajishan mine, Jiangxi province. During these visits, a 

great deal of information was gained on geology and 

mineral deposits of these areas, and a limited amount of 

resource and production data was obtained. The descriptions of the geology and resources of these deposits are 

based principally on information obtained during these 1984 

visits. 

GEOLOGIC SETTINGS OF TUNGSTEN 

DEPOSITS 

Nearly all of the important tungsten deposits of China 

are located in southeastern China, mostly in the provinces 

of Jiangxi, Hunan, and Guangdong (fig. 1; table 1). This 

region of approximately 800 by 800 km is roughly equivalent in area to that of the combined States of California and 

Nevada. Other deposits in China are located in the Fujian, 

Guangxi, and Yunnan provinces. Many of the largest and 

most productive deposits, both present and past, are located 

in the relatively small, mountainous region of Nanling, 

which lies in southern Jiangxi, southeastern Hunan, and 

northern Guangdong provinces. The principal tungsten 

deposits are quartz vein, stockwork or disseminated, and 

skarn types (table 1). Greisen and strata-bound deposits also 

occur. Most of the tungsten mines produce a variety of 

byproducts; the most common are tin, molybdenum, and 

bismuth. 

The regions in which most of the tungsten deposits 

are found are geologically complex; sequences of Proterozoic and Paleozoic clastic and carbonate-rich sedimentary 

rocks have been repeatedly folded and faulted and intruded 

by plutonic rocks of several ages. The deposits are closely 

associated with highly evolved, leucocratic granites that 

show enrichment in many lithophile elements and are 

generally of Yanshanian (Jurassic and Cretaceous) age. 

Tectonics and Structure 

The region of southeastern China where most of the 

tungsten deposits are found is called the South China 

Accretionary Fold Belt (Zhang and others, 1984) and is also 

called the East China Continental Margin Domain (Yang 

and others, 1986). It consists of two fold zones, the 

Xianggui and Min-Yue, separated by the Jien'ou Uplift 

(Yang and others, 1986). This region has been a complex 

continental margin since the middle Proterozoic and was 

subjected to repeated magmatism, folding, and faulting 

during the Paleozoic and Mesozoic eras. 

From Late Proterozoic (Sinian) through Silurian time, 

the region was a passive continental margin along the 

eastern border of the Yangtze craton, where sequences of 

flysch, graywacke, carbonates, and minor volcanic rocks 

accumulated (Zhang and others, 1984). Near the end of the 

12 Contributions to Commodity Geology Research 

early Paleozoic, these strata were folded, metamorphosed, 

and intruded by granitic plutons forming the Caledonian 

basement (Yang and others, 1986). Shallow marine and 

terrestrial sedimentary rocks, including carbonates, were 

deposited during the late Paleozoic and Triassic. Following 

the Triassic, the Mesozoic Circum-Pacific volcanic belt 

began to take form and evolve. As part of that belt, this 

region was subjected to major episodes of folding, faulting, 

and igneous activity. The Mesozoic marked the end of 

large-scale marine transgressions and the start of active 

westward-directed subduction in south China (Yang and 

others, 1986). Profuse magmatic activity during the Jurassic 

and Cretaceous periods (Y anshanian) was accompanied by 

the formation of deposits of tungsten, tin, molybdenum, 

and other metals throughout most of southeastern China. 

Association with Granitoid Rocks 

Granitoid rocks of southeastern China have been 

classified into two major types: (1) transformation or crustal 

and (2) syntexis or transitional (Xu and others, 1982). The 

former rocks are highly evolved granites with greater than 

70 percent Si02 ; low CaO, MgO, Ti02 , and total Fe; and 

high Na20 and K20. These granites are similar to S-type or 

ilmenite-type granites and are thought to be formed by the 

melting of continental crust. They are commonly associated 

with tungsten, tin, niobium, and tantalum deposits. The 

syntexis granitoids have compositions ranging from quartz 

diorite to monzonite and Si02 generally ranging from 56 to 

70 percent. They are similar to I-type or magnetite-type 

granitoids and are thought to be formed by mixing of 

magma from the upper mantle with continental crust. Some 

tungsten and many copper and molybdenum deposits are 

associated with syntexis granitoid plutons. 

The granites that are genetically linked to most of the 

tungsten deposits are strikingly similar to specialized tin or 

S-type granites described in many other parts of the world 

and are also similar to Climax-type granites of the Western 

United States. They differ from most of the granitic rocks of 

the Cordilleran region of North America that occur with 

skarn tungsten deposits in California, Nevada, Montana, 

and northwestern Canada. These Cordilleran granitic rocks 

are generally more mafic, have lower silica contents, and 

are less evolved than the Chinese tungsten granites; they 

have been interpreted as variably contaminated I-type granites (Newberry and Swanson, 1985). 

DESCRIPTION OF DEPOSITS 

Most of the China's tungsten production, past and 

present, is from wolframite-bearing quartz-vein deposits 

that occur both within granite plutons (endocontact deposits) and in the metasedimentary rocks adjacent to granite 

bodies (exocontact deposits). Since the 1960's, however, 
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0 100 200 300 MILES 

0 1 00 200 300 KILOMETERS 

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• Major mine or mining district * Major mine or mining district visited 

Major city 

Figure 1. Locations of major tungsten mines and districts in southeastern China. Xihuashan and Piaotang mines are located in Dayu district. 
Table 1. Deposit types, lithologies, and ages of host and associated igneous rocks and the references for mines and 

districts shown in figure 1 

Age and lithology of Age and I ithology of 

Name Province Deposit type associated igneous References host rocks rocks 

Xingluokeng ....... Fujian Porphyry/stockwork/ Jurassic granite; Devo- Jurassic granite Liu, 1982. 

vein. nian hornfels. 

Lianhuashan ........ Guangdong Porphyry/stockwork Cretaceous quartz por- Cretaceous quartz Lu, 1985; Bai and othphyry; Early Jurassic porphyry. ers, 1983; Tan, 1983; 

sandstone. Li and others, 1982. 

Wengyuan ......... ----do.---- Vein Jurassic granite; Devo- Jurassic granite Li and Wang, 1955. 

nian sandstone. 

Yochang .......... ----do.---- ----do.---- Jurassic granite; Per- ----do.---- Do. 

rnian sandstone, 

shale. 

Damingshan ..... .. Guangxi Stratiform/stockwork/ Devonian sandstone, Cretaceous granite Ma, 1982; Wan, 1982 . 

vein. shale. 

Shizhuyuan ........ Hunan Stockwork/skarn/ Devonian limestone Jurassic granite Wang and others, 

greisen. 1982. 

Yangjiatan •• 0 ••••• ----do.---- Vein Paleozoic metasedi- Mesozoic granite Carter and Kiilsgaard, 

mentary rocks. 1983. 

Y aogangxian ....... ----do.---- Vein/skarn Devonian sandstone Jurassic granite Wang and others, 

1930. 

Dajishan .......... Jiangxi Vein/disseminated Cambrian phyllite, ----do.---- Li and Wang, 1955; 

slate, sandstone. Shi and Hu, 1986; 

Chang, 1974. 

Dayu (includes ----do.---- Vein/stockwork Jurassic granite; Cam- ----do.---- Wu and Mei, 1982; 

Xihuashan and brian sandstone, Wang and Zhou, 

Piaotang) ........ phyllite, slate. 1982. 

Gueimeishan ....... ----do.---- ----do.---- Cambrian, Ordovician ----do.---- Hsu, 1943. 

quartzite, phyllite. 

Huangsha ......... ----do.---- Vein Cambrian quartzite, ----do.---- Chen and Hu, 1982; 

slate. Xia and others, 

1982. 

Pangushan ......... ----do.---- Vein/stockwork Devonian sandstone ----do.---- Hsu, 1943; Cai and 

others, 1982. 

Shangping ......... ----do.---- Vein Proterozoic, Cambrian ----do.---- Hsu, 1943. 

phyllite, quartzite. 

Xialong ........... ----do.---- ----do.---- Proterozoic, Cambrian ----do.---- Do. 

phyllite, quartzite. 

Y angchuling ....... ----do.---- Porphyry/stockwork Jurassic granodiorite Jurassic granodiorite Yan and others, 1980. 

porphyry. porphyry. 

Baishapo .......... Yunnan Skarn/vein/placer Triassic limestone Cretaceous granite Anstett and others, 

1985. 

14 Contributions to Commodity Geology Research 
many other kinds of tungsten deposits have been discovered 

in China, and these deposits will become increasingly 

important as sources of tungsten. These kinds of deposits 

include skarn, stockwork or porphyry, greisen, disseminated, and strata-bound. 

During October 1984, four major tungsten deposits in 

southeastern China were visited by the author and two other 

USGS geologists. These visits were arranged by members 

of the Chinese Academy of Geological Sciences, Ministry 

of Geology and Mineral Resources, as part of an exchange 

between that agency and the USGS. This exchange was 

focused on the study and comparison of environments of ore 

deposition and the genesis of deposits of tungsten, tin, 

niobium, and tantalum in southeastern China and the 

Western United States. The Chinese deposits visited 

included the Shizhuyuan deposit, Hunan province; the 

Xihuashan and Piaotang deposits in the Dayu district, 

Jiangxi province; and the Dajishan deposit, Jiangxi province (fig. 1). These represent a variety of deposit types 

including quartz-vein, skarn, stockwork, greisen, and disseminated. Large mines are present at two of these deposits, 

Xihuashan and Dajishan, and these mines have a long 

history of production; the Shizhuyuan and Piaotang deposits 

are being developed for production. 

Shizhuyuan Mine 

Shizhuyuan is the largest known tungsten deposit in 

the world with an estimated 627,000 metric tons of contained W03 (Anstett and others, 1985). It was discovered in 

the 1950's in southeastern Hunan province (fig. 1). Other 

mines in the district produce copper, lead, and zinc. 

Shizhuyuan is presently being mined on a small scale and is 

being developed as a large mine-mill complex that will 

produce up to 5,000 tons per day (Ye Qingtong, oral 

commun., 1984). 

The deposit is hosted by argillaceous limestone of 

Late Devonian age in the contact zone of the Qianlishan 

granite stock of Jurassic (Early Yanshanian) age (Wang and 

others, 1982). The stock is composite, consisting of at least 

four phases of granite, granite porphyry, and quartz porphyry, which are highly evolved and peraluminous, have 

silica contents of greater than 70 percent, and are enriched 

in tin, tungsten, molybdenum, and bismuth. 

The deposit is large and complex; it occurs above the 

contact between the stock and the overlying metasedimentary rocks and dips to the east (fig. 2). The body of 

mineralized rock is about 1,000 m long (north-south), 600 

to 800 m wide (east-west), and generally 200 to 300m thick 

with a maximum thickness of about 500 m (Wang and 

others, 1982). The deposit has been subdivided into four 

zones based on kind and grade of ore (fig. 2): 

Zone I-The uppermost zone, 50 to 220m thick, consists of 

a stockwork of cassiterite-sulfide-quartz veins in marble. 

w Dm E 

-+-+--+~ + 

+ + + + + ':to... + 

+ + '1- + + + + +"-.+ + + + + + + + + + + +~ 

+ + + + + + + + + + + + + + + + + + + + + + Jg + + + + + + • + + + + + + + + + + + + + 

+ + + + + + + + + + + • + + + + 0 100 METERS + ++~. 

Figure 2. Generalized cross section through the 

Shizhuyuan deposit showing ore zones I to IV (explanation in text). Other units are Dm, Devonian dolomitic 

marble; jqp, jurassic quartz porphyry; jg, jurassic granite 

and porphyritic granite; Sk, skarn with subeconomic concentrations of ore minerals. Modifi¢d from unpublished 

data of Chinese Academy of Geological Sciences. 

The veins are closely spaced and g~nerally less than 1 em 

thick. The average grade of tin is about 0.17 percent, but 

tungsten, molybdenum, and bismuth are very low, each 

usually less than 0.05 percent. 

Zone II-Below the tin-bearing stockwork zone is a zone in 

which garnet skarn has selectively replaced favorable 

beds within the marble. The skarn layers are lenticular to 

stratiform and contain scheelite, cassiterite, molybdenite, 

bismuthinite, and various beryllium minerals in addition 

to calc-silicate minerals, such as .garnet and pyroxene, 

and quartz. The number and thickness of the skarn layers 

increase downward toward the granite contact; unreplaced marble is rare or absent in 1 the lower part of the 

zone. This zone is 10 to 150 m thick and contains 

approximately 0.21 percent tungsten, 0.15 percent tin, 

0.02 percent molybdenum, and 0.10 percent bismuth. 

Zone III-Adjacent to the granite stock is a zone that 

consists of complex pyroxene-garnet-sulfide skarn cut by 

a stockwork of quartz veins. 'Iihese veins range in 

thickness from a few centimeters to about 0. 5 m and 

increase in number toward the granite contact; close to 

the contact they commonly exceed: 50 percent by volume 

of the contact zone. Most of the ore minerals are 

contained in these veins, although the skarn also contains 

significant concentrations of tungsten and other metals. 

Both wolframite and scheelite occur in the veins, but 

scheelite is the principal tungsten-ibearing mineral in the 

skarn between the veins. This zone ranges in thickness 

from 40 to 200 m and contains the highest grades of 

tungsten, molybdenum, and bismuth. The approximate 

grades are 0.50 percent tungsten, 0.12 percent molybdenum, 0.18 percent bismuth, and 0.09 percent tin. 

Zone IV-In places the mineralization is found below the 

granite-skarn contact forming an ore zone in greisenized, 

Tungsten-Geology and Resources of Deposits in Southeastern China 15 
sw 

0 

Figure 3. Generalized longitudinal section through the 

Xihuashan and Piaotang tungsten deposits in the Dayu 

district. Other vein systems are indicated by heavy lines. 

I, upper limits of ore zones; II, lower limits of ore zones. 

silicified granite. This type is relatively thin and discontinuous, usually less than a few meters thick. Ore grades 

are similar to those in zone III. 

Strong metal zonation is evident in zones I to III. Tin 

is highest in zone I and decreases toward the granite 

contact. Tungsten, molybdenum, and bismuth all increase 

toward the granite contact. Tungsten is less than 0.05 

percent in zone I and increases to about 0. 5 percent in zone 

III. Molybdenum and bismuth show similar increases from 

zones I to III. 

Xihuashan Mine 

The Xihuashan mine is the largest mine in the Dayu 

district (fig. 1) and is the most famous tungsten mine in 

China, having a history of production dating back to 1908. 

Prior to 1949, the area was mined by many individuals in 

surface and shallow underground workings. Since 1949, the 

mining has been conducted by the government through the 

development of a large underground mine and a mill for 

processing of the ore (Zhou Yuzhen, oral commun., 1984). 

In 1984, the Xihuashan mine was producing at a rate 

of 3,000 metric tons (t) of ore per day and 2,500 t of 

tungsten concentrate (containing 65 percent W03) per year. 

Molybdenum, tin, and bismuth are also recovered as 

byproducts. Since 1960, when centralized, large-scale mining and milling began, the mine has produced about 75,000 

t of tungsten concentrate. The ore reserves in 1984 were 

110,000 t of W03 (87 ,232 t contained tungsten) (Zhou 

Yuzhen, oral commun., 1984). 

The deposit consists of a system of wolframite-quartz 

veins in the southwest part of the Xihuashan stock of 

Jurassic age, which has intruded Late Proterozoic and 

Cambrian metasedimentary rocks. The stock is exposed 

over an area of about 24 km2 and is composite; four stages 

of biotite granite plus a stage of granite porphyry are 

recognized. All granitic stages are highly evolved; they are 

high in silica content (74-76 percent Si02) and are enriched 

16 Contributions to Commodity Geology Research 

PIAOTANG NE \_ -I---

METERS 

1000 

500 

SEA LEVEL 

5 KILOMETERS 

Modified from Yang and Lu (1982). Patterned area is 

granite batholith. Unpatterned area is sedimentary and 

metamorphic rocks. 

in many trace elements. Each of the four stages of biotite 

granite is accompanied by alteration and mineralization; 

these vary in intensity and type of metals. The Xihuashan 

mineralized zone occupies about 6.5 km2 of the stock; 

granites of the first two stages are the principal types 

exposed in the mine workings; these are closely related to 

the economic mineralization in the mine. 

The Xihuashan mine is an endocontact deposit in 

which the wolframite-quartz veins occur near the top and 

around the periphery of the stock (fig. 3). They pinch out 

rapidly where they cross the contact into the metasedimentary rocks. The mineralized zone consists of more than 650 

veins arranged in three sets of steeply dipping parallel 

veins. The veins have an average thickness of 0.4 m 

(maximum of 3.6 m) and length of 150 m (maximum of 

1,075 m). The orebodies in the veins show vertical zoning 

in the kind and concentration of ore minerals and in the style 

of alteration. The vertical extent of orebodies in each set of 

veins is commonly about 250 m (Zhou Yuzhen, oral 

commun., 1984). 

Piaotang Mine 

The Piaotang mine, also in the Dayu district, is 

located about 13 km northeast of the Xihuashan mine (fig. 

3). It is an exocontact deposit hosted by Cambrian metasedimentary rocks in the contact zone and above a granite 

cupola. It was discovered in 1918 but has been mined only 

in small-scale operations, mainly in surface and shallowunderground workings. In 1984, the mine was being developed for production, and a mill was under construction. The 

principal products of this operation will be tungsten and tin, 

but molybdenum, bismuth, copper, lead, zinc, beryllium, 

niobium, tantalum, and other commodities are planned 

byproducts (Wu Chang Zhu, oral commun., 1984). 

Whereas Xihuashan is a large-vein deposit, Piaotang 

is a small-vein deposit. Most veins at Piaotang are too thin 

to be mined individually, and ore bodies consist of many 
small, closely spaced veins. These veins occur within a 

mineralized zone that trends northeast, is more than 1. 3 km 

long, and is more than 500 m from the surface to the deepest 

levels that were affected by mineralization. From top to 

bottom, the zone shows systematic variations in the number 

and thickness of veins, from the "thread-vein" subzone at 

the top to the "big vein" subzone at the bottom. The No. 1 

or thread vein subzone consists of many closely spaced 

veinlets (three to eight veinlets per meter, about 0.5 to 3 em 

thick). The No.5 or big vein subzone, occurring at the level 

of the granite-metasediment contact, consists of a few 

widely spaced veins that are 30 to 200 em thick. The 

orebodies are generally found in the intermediate subzones, 

and the best grades are in the No. 3 or "big-veinlet vein" 

subzone where 2-cm to 5-cm veins are interspersed with 

large veins (3 to greater than 100 em, average about 15 em) 

and where the vein density is about 2.5 veins per meter. 

Veins constitute about 11 percent by volume of the total 

rock in this No. 3 subzone, which is about 200m from top 

to bottom (Wu Chang Zhu, oral commun., 1984). 

On the basis of crosscutting relations between alteration types and veins of different mineralogy, seven paragenetic stages have been defined at Piaotang. The earliest 

stage, stage 1, is contact metamorphism and silicification of 

the metasedimentary rocks. Where carbonate-bearing beds 

are present in the sequence, calc-silicate minerals have 

replaced the original carbonate and silicate minerals forming skarn. Stages 2 through 7 consist of sets of veins that 

show a progressive change in mineralogy from early stages 

of mainly oxides and silicates (wolframite, cassiterite, 

beryl, quartz), through intermediate stages of oxides, silicates, and sulfides (mainly molybdenite, chalcopyrite, 

sphalerite, galena, and pyrite), to late stages of sulfides, 

chlorite, quartz, fluorite, and carbonate minerals. Minerals 

of economic value are found mainly in the intermediate 

stages (stages 2 through 5) (Wu Chang Zhu, oral commun., 

1984). 

Dajishan Mine 

The Dajishan mine is one of the largest producing 

tungsten mines in China, having a mill capacity of 3,000 t 

of ore per day (Wu, 1982). The average grade of ore mined 

is about 0.25 percent W03 , and this value is upgraded to 

greater than 0.5 percent wo3 by preconcentrating through 

hand and photometric sorting prior to treatment in the mill. 

As at Xihuashan, the principal orebodies are tungstenbearing quartz veins. The Dajishan mine has a long history 

of production, having been worked for more than 60 years 

(Wu, 1982). 

The Dajishan mine is located near the edge of a 

granitoid batholith of Jurassic age. Two types of deposits 

are exposed in the underground workings of the mine. The 

principal one, which is the source of most of the past and 

present production, consists of sets of steeply dipping 

parallel quartz veins hosted by Cambrian metasandstone, 

slate, and phyllite. A second type consists of disseminated 

wolframite and beryllium-bearing artd niobium-tantalumbearing minerals in albite muscovite granite that occurs as 

an irregularly shaped intrusive body in the lower levels of 

the mine (Shi and Hu, 1986) (fig. 4). 

The quartz veins occur as west-trending to westnorthwest-trending parallel veins that dip steeply to the 

northeast. Hundreds of veins have been worked in the 

mineralized zone that is bounded on the east and west sides 

by northeast -trending faults. Orebod]es occur in a vertical 

range of over 500 m, and the mine area is underlain by a 

body of biotite-muscovite granite (fig. 4). Veins are 

variable in thickness from about 1 em or less to about 3m. 

Smaller veins (less than 1 m) contain higher grades and 

account for most of the economic mineralization, but some 

of the larger veins contain spectacular large clusters of 

wolframite crystals; individual crystals of up to 1 m long 

have been noted. A mass of nearly pure wolframite 

weighing about 2.5 twas taken out of one of the large veins 

and is now on display at the Great Hall of the People in 

Beijing (Teng Jian De, oral commun., 1984). The principal 

ore minerals are wolframite and sche¢lite (ratio ranges from 

3:1 to 4:1). The veins also contain minor amounts of sulfide 

minerals and native bismuth plus a variety of silicate and 

oxide minerals. Molybdenum and bismuth are recovered as 

byproducts in the mill (Wu, 1982). 

The muscovite granite body that contains the disseminated tungsten-niobium-tantalum-beryllium mineralization 

is exposed in the lower workings of the mine and is 

connected at depth with biotite-muscovite granite (fig. 4). 

The muscovite granite has a well+-developed pegmatoid 

margin, and the ore minerals are contained in the interior of 

the granite in spheroidal to ellipsoidal masses, 10 to 100 em 

in diameter, that contain up to 30 p4rcent W03 plus minor 

amounts of beryllium-bearing and niobium-tantalumbearing minerals. This mineralization is earlier than that 

found in the quartz veins, which cut the muscovite granite 

as well as the metasedimentary rocks (Shi and Hu, 1986). 

PRODUCTION AND RESOURCES 

China is the leading producer of tungsten in the world 

and has been a leader since the early 1900's. During the 

period of 1913 to 1937, China contributed about 37 percent 

of the world's production (Li and 'Wang, 1955). China's 

1986 estimated production was approximately one-third of 

the total world production of 42,474 t of contained tungsten 

(Smith, 1988). China's role as a supplier of tungsten to 

world markets has strengthened in recent years, especially 

since about 1980. During the period of 1980 to 1986, the 

production of tungsten in China was maintained at high 

Tungsten-Geology and Resources of Deposits i~ Southeastern China 17 
....J 

UJ 

> w 

...J 

<( 

UJ 

(/) 

w 

> 

0 

aJ 

<( 

(/) 

c: 

UJ 

1-

w 

~ 

700~~----------------------------------~N 

500 

300 

£s 

+ + + 

/+ + + + + + + + + 

/ + + + + + + + + + 

+ ........... - - -- ~c + + + + + + + + + + + + + + + + + + 

++++++++++++++++++++ 

~ 

v 

Jmbg 

Figure 4. Generalized cross section through the Dajishan 

mine area. V, wolframite-quartz veins; F, fault; £s, Cambrian metasedimentary rocks; Jmg, Jurassic muscovite 

granite with tungsten-niobium-tantalum-beryllium ore 

bodies; jmbg, Jurassic muscovite biotite granite. Dashed 

line indicates area where contact is approximate. Modified 

from Chang (1974). 

levels, in the range of 12,500 to 15,000 t of contained 

tungsten per year (Chin, 1983; Smith, 1988). Over this 

same period the production by U.S. mines dropped dramatically from 2,738 t of contained tungsten in 1980 (U.S. 

Bureau of Mines, 1985) to 817 t in 1986 (U.S. Bureau of 

Mines, 1988). This drop in U.S. production is mainly the 

result of the fall of market prices from an average of $144 

per metric ton unit W03 in 1980 (U.S. Bureau of Mines, 

1985) to an average of $56 in 1986 (Smith, 1988). 

Also during the period of 1980 to 1985, there has 

been a dramatic shift in the type of products produced and 

exported by China and corresponding changes in the importation of these products into the United States. Prior to 

1980, nearly all of China's tungsten production was in the 

form of tungsten concentrates. Since that time, however, 

there has been a rapid increase in the production of 

value-added products such as ammonium paratungstate 

(APT) and tungsten oxide. As a result, a major trend in the 

U.S. trade patterns has been the shift from importing 

tungsten concentrate to importing these value-added products (Thurber, 1985). In 1980, the United States imported 

tungsten concentrate containing 918 t tungsten and APT 

with 10 t contained tungsten from China (Thurber, 1985). 

18 Contributions to Commodity Geology Research 

By 1986, the amount of tungsten in concentrate had fallen 

to 302 t, whereas the amount of tungsten in APT had risen 

to 971 t (Smith, 1988). 

The aggressive production and pricing policies of 

Chinese producers have had a serious negative effect on 

both world and U.S. tungsten mining and refining 

industries. All of the major U.S. operations, such as the 

Pine Creek mine near Bishop, Calif., and the Emerson and 

Springer mines in Nevada, have been closed or are operating on greatly reduced schedules. Exploration for and 

development of tungsten deposits have virtually been discontinued in the United States. In China, however, production continues at high levels and could be increased if more 

deposits are put into production. For example, in 1984 the 

Piaotarig and Shizhuyuan mines were being developed for 

production. Shizhuyuan is the largest known tungsten 

deposit in the world and, if put into production at the 

planned capacity of 5,000 t of ore per day, would be the 

largest producing mine in China (Y e Qingtong, oral commun., 1984). 

Certainly much of the success that China has gained 

in competition with the rest of the world in tungsten 

marketing stems from the low cost of labor there. China's 

mines are labor intensive but, unlike the situation in U.S. 

mines, labor costs are a much lower percentage of overall 

operating costs. For underground mines in the United 

States, wages account for 44 to 64 percent of total costs, 

whereas in China wages for labor make up only 10 to 25 

percent of the total costs (Chen, 1986). In China, the yearly 

wage for an underground worker is about 3,000 yuan ($937 

at a rate of 3.2 yuan per dollar) versus about $30,000 per 

year for an underground worker in the United States (Chen, 

1986). At tungsten mines and mills, these low labor rates 

permit hand sorting of ore prior to milling. This practice, 

which is prohibited by high labor costs in the United States, 

allows lower grade ores to be mined economically, thus 

prolonging the lives of many mines (Wu, 1982). At 

Xihuashan, for example, approximately 200 people were 

employed in the hand sorting of ore in 1984. 

Besides being the world's leader in production, China 

also has a Jllajor share of the world's resources of tungsten. 

Recent estimates (Smith, 1988) indicate that China has 

reserves of 1,200,000 t of contained tungsten and a reserve 

base (reserves plus marginal reserves and some subeconomic resources) of 1,230,000 t contained tungsten. These 

reserves are 42.9 percent of the world's estimated total of 

2,800,000 t contained tungsten. 

SUMMARY 

As the leading producer of tungsten, China dominates 

the world's tungsten market. Favorable factors contributing 

to this dominance are its large tungsten ore reserves, the low 

cost of labor in China, aggressive production and pricing 
policies by Chinese producers, and the recent changes in 

government policies that promote expanded trade with 

market economy countries. 

China's tungsten deposits are located in the southeastern part of the country in a region that is geologically 

complex. Many of the mines having the largest production 

and longest history of operation are located in the Nanling 

region in the southern parts of Hunan and Jiangxi provinces 

and the northern part of the Guangdong province. Southeastern China has been a complex continental margin since 

Late Proterozoic time and during the Paleozoic and Mesozoic eras the sedimentation was repeatedly interrupted by 

orogenic periods of faulting, folding, and igneous activity. 

Of greatest significance to the formation of tungsten deposits was the widespread and abundant granitic plutonism of 

the Jurassic and Cretaceous periods (Yanshanian). Most of 

the major tungsten deposits are directly associated with 

granitic rocks of this age. 

The occurrence of so many large and productive 

tungsten deposits in a relatively small area of the world such 

as southeastern China has long been a source of controversy 

and questions. What is the source of the tungsten and 

associated metals? Is the source sedimentary or magmatic? 

Is the mantle of the Earth unusually enriched in tungsten in 

this part of the world? Are the tungsten deposits the result of 

a single cycle or multiple cycles of magmatism, erosion, 

and sedimentation? 

Three principal factors seem to control the occurrence 

of tungsten deposits in southeastern China. They are (1) the 

occurrence of source rocks, mainly sedimentary, which are 

enriched in tungsten, (2) a favorable tectonic environment 

over a long period of time, and (3) a long history of cyclic 

and widespread granitic plutonism. Some of the oldest 

sedimentary units such as the Banxi Group of Late Proterozoic age (Yang and others, 1986) show appreciable enrichment in tungsten. In western Hunan province, rocks of this 

group contain 5 to 15 parts per million (ppm) tungsten. 

Even higher levels (up to about 800 ppm tungsten) have 

been detected in Proterozoic and Paleozoic sedimentary 

rocks in southeastern Hunan and southern Jiangxi provinces 

(Xu and others, 1982). The anomalies in the sedimentary 

rocks may have been inherited from an uneven distribution 

of tungsten in the upper mantle in the region of southeastern 

China. Evidence of this enrichment is seen in a range of 

tungsten values in mafic and ultramafic Precambrian rocks 

from different parts of southeastern China (Xu and others, 

1982). The tectonic environment of southern China has, 

through a long history of sedimentation interrupted by 

orogenies, promoted a recycling of tungsten and associated 

metals through sedimentation, erosion, and magmatism into 

deposits of increasing degrees of enrichment over geologic 

time. It has also provided favorable zones for the movement 

of magma and hydrothermal fluids and favorable environments for the final deposition of economic deposits. Granitic plutonism, the result, in part, of the tectonic environment, has occurred periodically since Late Proterozic time. 

The granitoid rocks of southern China have average tungsten values of 3.6 ppm, which is about 2.4 times the clarke 

value (Liu and others, 1982). Studies show that the highest 

values are found in evolved felsic, s~lica-rich granites and 

that there is a progressive enrichment of tungsten in these 

granites from oldest to youngest (Liu and others, 1982). 

Regional variations have also been • determined, and the 

highest value (5.2 ppm) was found in granites in the 

Nanling region where most of the lar$est and most productive tungsten mines are located (Liu and others, 1982). 

Tungsten deposits usually occur with ~he youngest granites, 

usually Jurassic, in the regions, such, as Nanling, in which 

they are found. These granites are the transformation or 

crustal type and are enriched in tungsten and other metals 

such as tin, molybdenum, bismuth, niobium, and tantalum. 

They have formed as a result of anatexis of crustal material, 

either metasedimentary or felsic igneous rocks, which were 

previously enriched in tungsten and associated metals. 

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Information Circular 9025, 51 p. 

Bai Yuzhen, Man Fasheng, Ni Shoubin, and Li Tong, 1983, K-Ar 

dating of Lianhuashan tungsten ore , deposit: Geochimica, v. 

6, no. 2, p. 133-139. 

Cai Jianming, Liu Ruolan, and Zeng Gu~gsheng, 1982, Study on 

fluid inclusion and its relation to mineralization of Pangushan 

tungsten deposit, Jiangxi Provine¢, China, in Hepworth, 

J.V., and Yu Hong Zhang, eds., Tqngsten geology, Jiangxi, 

China: Bandung, Indonesia, ESCAP/RMRDC, p. 233-243. 

Carter, W.D., and Kiilsgaard, T.H., 1983, Landsat analysis ofthe 

Yangjiatan tungsten district, Hunan Province, People's 

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Weill, G., eds., Remote sensing and mineral exploration: 

Advances in Space Research, v. 3, no. 3, Pergamon Press, p. 

113-123. 

Chang, Tsung-chen, 1974, Report on a Ta-, Nb-, W-, and 

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256. 

Chen Yunhe, 1986, Selective underground mechanization: Engineering and Mining Journal, v. 187, no. 5, p. 31-33. 

Chen Zunda and Hu Lisui, 1982, The geological characteristics 

and primary zoning of Huangsha vein-type tungsten deposit, 

in Hepworth, J.V., and Yu Hong Zhang, eds., Tungsten 

geology, Jiangxi, China: Bandungj Indonesia, ESCAP/RMRDC, p. 257-268. 

Chin, Edmond, 1983, The mineral in<Justry of China, in U.S. 

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Printing Office, p. 225-249. 

Hsu, Ke-Chin, 1943, Tungsten deposits of southern Kiangsi, 

China: Economic Geology, v. 38, 'no. 6, p. 431-474. 

Tungsten-Geology and Resources of Deposits in Southeastern China 19 
Li, K.C., and Wang, C.Y., 1955, Tungsten, its history, geology, 

ore-dressing, metallurgy, chemistry, analysis, applications, 

and economics: New York, Reinhold Publishing Corp., 

506 p. 

Li Tung, Man Fasheng, Bai Yuzhen, and Ni Shoubin, 1982, 

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Liu Wengzhang, 1982, Geological features of mineralization of 

the Xingluokeng tungsten (molybdenum) deposit, Fujian 

Province, in Hepworth, J.V., and Yu Hong Zhang, eds., 

Tungsten geology, Jiangxi, China: Bandung, Indonesia, 

ESCAPIRMRDC, p. 339-348. 

Liu Yimao, Yang Qishun, Zhu Yunjie, and Jiang Qingsong, 1982, 

Tungsten abundance and its evolution in granitoid rocks of 

south China, in Hepworth, J.V., and Yu Hong Zhang, eds., 

Tungsten geology, Jiangxi, China: Bandung, Indonesia, 

ESCAP/RMRDC, p. 349-357. 

Lu Huangzhang, 1985, Fluid inclusion studies of a new type of ore 

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Ma Linqing, 1982, The geological characteristics of Damingshan 

sedimentary-magmatic hydrothermal wolframite deposit, 

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China: Bandung, Indonesia, ESCAP/RMRDC, p. 375-384. 

Newberry, R.J., and Swanson, S.E., 1985, Granites associated 

with tungsten skarns, in Taylor, R.P., and Strong, D.P., 

eds., Granite-related mineral deposits: Halifax, Nova Scotia, 

Canada, CIM Conference on Granite-Related Mineral Deposits, p. 197-199. 

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the Dajishan mine, Jiangxi Province, China [abs.]: Terra 

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Market Metalworking News, Tungsten Special Issue, February 6, 1985, p. 9A, 11A. 

U.S. Bureau of Mines, 1985, Mineral commodity summaries 

1985: U.S. Bureau of Mines, p. 168-169. 

---1988, Mineral commodity summaries 1988: U.S. Bureau 

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Wan Bing, 1982, The Damingshan strata-bound tungsten deposits 

in Guangxi Zhuang Autonomous Region, China, in Hep110 Contributions to Commodity Geology Research 

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Jiangxi, China: Bandung, Indonesia, ESCAP/RMRDC, p. 

403-412. 

Wang Changlie, Xu Youzhi, Xie Ciguo, and Xu Wenguang, 

1982, The geological characteristics of Shizhuyuan W-SnMo-Bi deposit, in Hepworth, J.V., and Yu Hong Zhang, 

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ESCAPIRMRDC, p. 413-425. 

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7-11. 

Wang Zehua and Zhou Yuzhen, 1982, Major features of twolayered type mineralization in Xihuashan mine and its genetic 

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Tungsten geology, Jiangxi, China: Bandung, Indonesia, 

ESCAPIRMRDC, p. 427-436. 

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in China, in Tungsten -1982, Proceedings of the Second 

International Tungsten Symposium, San Francisco, June 

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multi-phase mineralization in Xihuashan tungsten ore field, 

in Hepworth, J.V., and Yu Hong Zhang, eds., Tungsten 

geology, Jiangxi, China: Bandung, Indonesia, ESCAPIRMRDC, p. 437-449. 

Xia Hongyuan, Liang Shuyi, Xie Weixin, and Shuai Dequan, 

1982, Primary zoning of Huangsha tungsten deposit and its 

genesis, in Hepworth, J.V., and Yu Hong Zhang, eds., 

Tungsten geology, Jiangxi, China: Bandung, Indonesia, 

ESCAP/RMRDC, p. 451-461. 

Xu Keqin, Hu Shouci, Sun Minzhi, Zhang Jingrong, Ye Jun, and 

Li Huiping, 1982, Regional factors controlling the formation 

of tungsten deposits in south China, in Hepworth, J. V., and 

Yu Hong Zhang, eds., Tungsten geology, Jiangxi, China: 

Bandung Indonesia, ESCAPIRMRDC, p. 473-488. 

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Mining Geology Special Issue, No. 8, pp. 215-221. 

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J.V., and Yu Hong Zhang, eds., Tungsten geology, Jiangxi, 

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Chapter J 

Tungsten-Grades and Tonnages of Some 

Deposits 

By W. DAVID MENZIE, GAIL M. JONES, and JAMES E. 

ELLIOTT 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract Jl 

Introduction Jl 

Tungsten Skarn Deposits Jl 

Wolframite-Bearing Quartz Vein Deposits J3 

Porphyry Tungsten-Molybdenum Deposits JS 

Discussion JS 

References J 6 

FIGURES 

1-3. Graphs showing: 

1. Grade-tonnage model for tungsten skarn deposits J3 

2. Grade-tonnage model for quartz-wolframite vein deposits JS 

3. Grade and tonnage domains for tungsten skarn, wolframite-bearing quartz 

vein, and tungsten-molybdenum porphyry deposits J6 

TABLES 

1. Deposits used to construct the tungsten skarn model J2 

2. Deposits used to construct the wolframite-bearing quartz vein model J4 

Contents Ill 

Tungsten-Grades and Tonnages of Some Deposits 

By W. David Menzie, Gail M. jones, and james E. Elliott 

Abstract 

Descriptive and grade/tonnage models of ore deposits are important tools for mineral exploration, regional 

mineral-resource assessment, and commodity availability 

studies. Tungsten has been produced as a primary commodity mostly from two deposit types: scheelite-bearing 

skarns and wolframite-bearing quartz veins. Grade/tonnage models built with data from 36 skarn and 19 vein 

deposits indicate that these deposit types do not differ 

greatly in tonnage or grade. Half of the scheelite-bearing 

skarns have tonnages greater than just less than 1 million 

metric tons, and half of the wolframite-bearing quartz 

veins have tonnages that exceed 680 thousand metric 

tons. Although the veins have slightly smaller tonnages 

than the skarns, they have slightly higher grades. Half of 

the veins have grades that exceed 0.8 weight percent 

wo3, while half the skarns have grades that exceed 0.64 

weight percent W03 • In contrast to their similarity in 

grades and tonnages, vein and skarn deposits differ in 

important characteristics including tectonic setting, environment of formation, morphology, mineralogy, and 

associated alteration assemblages. 

Although tungsten has been produced mainly from 

two types of deposits, it is known to occur in a variety of 

geologic settings, and new types of deposits are being 

recognized. From the perspective of potential supply, 

porphyry (or stockwork) tungsten-molybdenum deposits 

may be an important new deposit type. Examples include 

the deposits at Mount Pleasant, New Brunswick, Canada; 

Logtung, Yukon Territory, Canada; Yangchuling, Jiangxi 

province, People's Republic of China; and Xingluokeng, 

Fujian province, People's Republic of China. These deposits are associated with composite granites and possess 

distinctive metals (W, Mo, Bi) and alteration assemblages. 

Available grade/tonnage data of these deposits range from 

tens to hundreds of millions of metric tons of ore containing from 0.1 to 0.3 percent wo3. 

INTRODUCTION 

Descriptive and grade/tonnage models are important 

tools for mineral exploration and regional resource assessment. Such models are established for many types of 

deposits including rhyolite-hosted, replacement (exhalative?), vein, greisen, and skarn tin deposits (Reed, 1986a~; 

Reed and Cox, 1986; Reed and others, 1986; Menzie and 

others, 1988). This paper discusses and presents grade 

tonnage models of scheelite-bearing skarn and wolframitebearing quartz vein deposits, presently the most important 

sources of tungsten. Another deposit type-porphyry 

tungsten-molybdenum-may be an important source of 

tungsten in the future and is discussed briefly. 

Tungsten has been produced as a primary commodity 

mainly from two deposit types, scheelite-bearing skarns and 

wolframite-bearing quartz veins, that occur in plutonic 

environments. The plutonic environment, however, is not 

the only geologic environment in which tungsten occurs. 

Others include shallow, low-temperature geologic 

environments such as hot springs and lake brines (Hobbs 

and Elliott, 1973). In addition, tungsten deposits have been 

identified in new environments including the shallow 

intrusive (porphyry), submarine volcano-sedimentary 

(strata-bound), and subaerial volcanic (hot springs), and the 

environments of formation of some previously known 

deposits have been reinterpreted. 

TUNGSTEN SKARN DEPOSITS 

Tungsten skarn deposits occur at or near contacts of 

carbonate rocks and calc-alkaline granitic bodies, which 

vary from batholithic to stock size. The composition of 

intrusives that are associated with skarns may vary from 

granodiorite to granite (Newberry and Swanson, 1985; 

classification based on Streckeisen, 1975), and the intrusives usually have coarse-grained, equant to porphyritic 

textures. The granites form from water-undersaturated, 

contaminated "I" type magmas, and the skarns form at 

relatively high pressures (Newberry and Swanson, 1985). 

Tungsten skarns form at high temperatures ( 400-600 

°C) and under relatively reducing conditions compared to 

many other deposit types, such as porphyry copper deposits. However, the mineralogy of skarns and the composition 

of calc-silicate minerals define both reduced and oxidized 

types (Morgan, 1975; Einaudi and others, 1981). Many 

tungsten skams show a common sequence of discrete stages 

of formation. This sequence is (1) prograde thermal metamorphism, (2) high-temperature garnet-pyroxene-scheelite 

metasomatism, (3) lower temperature amphibole-biotiteTungsten-Grades and Tonnages of Some Deposits )1 
Table 1. Deposits used to construct the tungsten skarn 

model 

Deposit name Location Source of data 

Baily . . . . . . . . . . . . . . . . . Yukon Territory, Canada 5 

Brejui ................. Rio Grande de Norte, Brazil 16 

Calvert ................ Montana, U.S.A. 9 

Cantung . . . . . . . . . . . . . . . Northwest Territories, Canada 17 

Costabonne ............. Pyrennes, France 18 

Dublin Gulch ........... Yukon Territory, Canada 5 

Emerald-Dodger . . . . . . . . . British Columbia, Canada 1,11 

Gardnerville ............ Nevada, U.S.A. 21 

Gunmetal ............. . do. 21 

Hope Valley ............ California, U.S.A. 21 

Iron Mountain ........... New Mexico, U.S.A. 21 

Kara. . . . . . . . . . . . . . . . . . Tasmania, Australia 13 

King Island. . . . . . . . . . . . . do. 3 

Lost Creek ............. Montana, U.S.A. IO 

Lucky Mike . . . . . . . . . . . . British Columbia, Canada 4 

Mactung. . . . . . . . . . . . . . . Northwest Territories, Canada 4 

Maykhura .............. U.S.S.R. 11 

Molyhill . . . . . . . . . . . . . . . Northern Territory, Australia 13 

Mount Alexander ........ West Australia, Australia 13 

Milford ............... Utah, U.S.A. 6 

Nevada-Massachusetts . . . . Nevada, U.S.A. 

Nevada Scheelite. . . . . . . . . do. 

Osgood Range . . . . . . . . . . do. 

21 

I4,I9 

8 

Pine Creek ............. California, U.S.A. 2I 

Quixaba . . . . . . . . . . . . . . . Brazil II 

Ray Gulch . . . . . . . . . . . . . Yukon Territory, Canada 5 

Risby. . . . . . . . . . . . . . . . . do. 7 

Salau ................. Ariege, France 18 

Sangdong .............. Kan Won Province, Republic of I2 

Korea 

Stormy Group. . . . . . . . . . . Yukon Territory, Canada 5 

Tern Piute .............. Nevada, U.S.A. 20 

Tyrny Auz ............. North Caucasus, U.S.S.R. I1 

Uludag ................ Turkey 11,15 

Victory. . . . . . . . . . . . . . . . British Columbia, Canada 5 

Yellow Pine ............ Idaho, U.S.A. 2 

Ysxjoberg .............. Sweden 11 

Sources of data for tungsten skarn grade/tonnage model (table 1) 

1. British Columbia Department of Mines and Petroleum Resources, 

1973, Geology, Exploration and Mining in British Columbia, 

642 p. 

2. Cook, E.F., 1956, Tungsten deposits of south-central Idaho: Idaho 

Bureau of Mines and Geology Pamphlet No. 108, 40 p. 

sulfide metasomatism, and ( 4) chlorite-calcite-epidotequartz retrograde metamorphism and metasomatism 

(Meinert and others, 1981). Scheelite may be formed during 

stages 2, 3, and 4, but sulfides are generally restricted to 

stage 3. 

The formation of skarn deposits is controlled by the 

shape of the contact of the intrusive rock, by the presence of 

favorable beds in the host rock sequence, and by structural 

relations of the strata to the contact (Bateman, 1965; Hobbs 

and Elliott, 1973). Skams commonly form at irregularities 

in the contact, especially where there is an overhang of the 

granitic contact (Bateman, 1982). They form by the metaJ2 Contributions to Commodity Geology Research 

3. Danielson, M.J., 1975, King Island scheelite deposits, in Knight, 

C.L., ed., Economic geology of Australia and Papua New Guinea, v. 

l, Metals: The Australasian Institute of Mining and Metallurgy, 

Monograph Series no. 5, p. 592-598. 

4. Einaudi, M.T., Meinert, L.D., and Newberry, R.J., 1981, Skarn 

deposits, in Skinner, B.J., ed., Economic Geology, 75th Anniversary Volume: p. 317-391. 

5. Energy, Mines and Resources Canada, 1980, Canadian mineral 

deposits not being mined in 1980: Mineral Policy Sector, Internal 

Report MRI 80/7, 294 p. 

6. Everett, F.D., 1961, Tungsten deposits in Utah: U.S. Bureau of 

Mines Information Circular 8014, p. 40-41. 

7. Financial Times, 1986, Mining international yearbook: Essex, 

England, Longman Group Ltd., 547 p. 

8. Hotz, P.E., and Willden, R., 1964, Geology and mineral deposits of 

the Osgood Mountains quadrangle, Humboldt County, Nevada: U.S. 

Geological Survey Professional Paper 431, 128 p. 

9. Krohn, D.H., and Weist, M.M., 1977, Principal information of 

Montana mines: Montana Bureau of Mines and Geology, Special 

Publication 75,150 p. 

10. Larson, L.P., Lowrie, R.L., and Leland, G.R., 1971, Availability of 

tungsten at various prices from resources in the United States: U.S. 

Bureau of Mines Information Circular 8500, 65 p. 

11. Laznicka, Peter, compiler, 1973, Manifile-The University of Manitoba file of nonferrous metal deposits of the world, pt. 2: Winnipeg, 

University of Manitoba, Department of Earth Science, 767 p. 

12. Lemmon, D.M., and Ross, D.C., 1956, Resources, chap. II, in 

Materials survey-Tungsten: U.S. Department of Commerce, Business and Defense Services Administration, compiled for the Office 

of Defense Mobilization, p. 11-1-11-16. 

13. Louthean, Ross, ed., 1986, Register of Australian mining 1984-85: 

Sydney, Australia, Australian Consolidated Press Ltds., 488 p. 

14. Mining Congress Journal, 1979, v. 65, no. 7, p. 10, 13. 

15. Mining Magazine, 1979, v. 140, no. 6, p. 501. 

16. Ministero das Minas e Energia (Brazil), 1969, Relatorio Preliminar 

Sobre as Investigacoes Geological na Minas Brejue-R.N. (Projeto 

Tungstenio/Molibdeno), Recife, Brazil, 53 p. 

17. Pazour, D.A., 1979, Canada Tungsten to double production: World 

Mining, v. 32, no. 4, p. 50-54. 

18. Pouit, Georges, and Fortune, Jean-Pol, 1980, Metallogenesis of 

Pyrenees compared with that of the Southern Massif Central: 

International Geological Congress, 26th, Paris 1980, Excursion 205, 

p. 109-161. 

19. Schilling, J.H., 1964, Tungsten, in Mineral and water resources of 

Nevada: Nevada Bureau of Mines and Geology Bulletin 65, p. 

155-161. 

20. Wall Street Journal, 1977, Union Carbide advertisement, July 5, 

p. 7. 

21. Proprietary data. 

somatism of relatively pure marble or limestone, and their 

formation is enhanced where the bedding of the sedimentary 

rocks dips into, rather than away from, the intrusive 

contact. Other structures such as premineral faults and 

plunging troughlike features in the intrusive contact may 

also be important. 

The grade/tonnage model of scheelite-bearing skams 

is built with data from 36 deposits (table 1). The majority of 

the deposits are from the United States and Canada, but 

deposits from Australia, Brazil, France, Korea, and Sweden 

are also included. In most cases, the data include past 

production plus reserves and resources. Because it is 
commonly difficult to define precisely what constitutes a 

skarn deposit from mineral production, reserve, and 

resource data, all bodies of mineralized skarn associated 

with the contact of a particular intrusion are considered to 

belong to one "deposit." Thus physically separate skarns on 

opposite sides of an intrusion were considered to be parts of 

the same deposit in order to maintain consistency in the 

data. Lognormal distributions fit the observed distributions 

of both grade and tonnage, and the two variables are not 

significantly correlated (r=0.06). Ninety percent of the 

deposits contain at least 41,000 metric tons (t), half of the 

deposits contain just less than 1 million t (fig. 1). Ninety 

percent of the skarn deposits have grades of at least 0.30 

percent, half have grades of at least 0.64 percent, and 10 

percent have grades of at least 1.3 percent wo3 (fig. 1). 

WOLFRAMITE-BEARING QUARTZ VEIN 

DEPOSITS 

Wolframite-bearing quartz vein deposits are widely 

distributed and as recently as 1973 accounted for more than 

three-fourths of the world reserves of tungsten (Hobbs and 

Elliott, 1973). The great bulk of these reserves occur in 

southeastern China, the most productive region in the world 

for tungsten. 

These deposits are similar to most lode tin deposits 

and many molybdenum deposits in that they are found 

associated with highly evolved and highly differentiated 

granites that can be generally classified as specialized or 

tin-bearing granites (Tischendorf, 1977). These granites 

form multiphase, composite plutons of biotite or biotitemuscovite granite. In southeastern China, the majority of 

wolframite-bearing quartz-vein deposits are associated with 

granites of the early Y anshanian (mostly Jurassic in age) 

period (Yan and others, 1980) that are highly enriched in 

tungsten, tin, niobium, and tantalum and are compositionally similar to granites associated with Climax-type molybdenum deposits (Mutschler and others, 1981) in the United 

States and to tin-bearing granites (Tischendorf, 1977) in 

many other parts of the world. 

Found commonly with granite stocks or cupolas that 

form topographic highs or ridges of granite batholiths, these 

tungsten deposits occur both within the intrusive rock 

(endocontact) and in the adjacent metasedimentary rocks 

(exocontact). Wolframite-bearing quartz veins commonly 

are steeply dipping to vertical as at Xihuashan and Dajishan, southeastern China, but may be flat lying or subhorizontal as at Panasqueira, Portugal (Kelly and Rye, 1979). 

In many exocontact deposits in China, the quartz 

veining shows distinctive vertical zonation in the morphology and mineralogy of the veins and veinlets (Y an and 

others, 1980). The upper zone consists of closely spaced 

abundant quartz-mica veinlets containing small, subeconomic amounts of ore minerals such as wolframite and 

(/) 

1-

U) 

0 

0... 

w 

Q 

LL 

0 

z 

0 

i= 

c::: 

0 

Q.. 

0 

c::: 

Q.. 

(/) 

IU5 

0 

Q.. 

w 

Q 

LL 

0 

z 

0 

i= 

a: 

0 

0... 

0 

c::: 

Q.. 

0.8 

0.6 

0.4 

0.2 

EXPLANATION 

G Deposit 

0.0 L____J_ _ ___L _ ___L_ _ _L__...J.___J_~~----L----l....-=-_,1 

0.001 O.Q1 0.1 1.0 10.0 

1.0 

0.8 

0.6 

0.4 

0.2 

0.0 

MILLION METRIC TONS ORE 

EXPLANATION 

G Deposit 

0.1 0.16 0.25 0.40 0.63 1.0 1.6 

GRADE (PERCENT W03

) 

Number of 

Variable deposits in 90% 50% 

the model 

Ore tonnage, in 

million metric tons 36 0.041 0.80 

Average weight 

percent W03 36 0.30 0.64 

100.0 

2.5 

10% 

18 

1.3 

Figure 1. Grade-tonnage model for tungsten skarn 

deposits. 

cassiterite. Downward, the veinlets increase in thickness 

but decrease in number through an intermediate zone that 

contains most of the economic mineralization to a lowermost subeconomic zone of sparse, thick veins (typically 1 to 

3m) near or within the intrusion. These zoned systems also 

show complex parageneses in crosscutting vein relations 

that include silicate, oxide, sulfide, and carbonate stages 

(Yan and others, 1980). The silicate stage is characterized 

by formation of calc-silicate and other silicate minerals as 

skarn or hornfels in the metasedimentary rocks of the 

contact zone. This stage is followed by the oxide, or main 

ore, stage that includes most of the wolframite, scheelite, 

Tungsten-Grades and Tonnages of Some Deposits J3 
Table 2. Deposits used to construct the wolframitebearing quartz vein model 

Deposit name Location Source of data 

Bir Tawila . . . . . . . . . . . . . . . . . . . Saudi Arabia 

Carrock Fell . . . . . . . . . . . . . . . . . . England 

Chicote Grande. . . . . . . . . . . . . . . . Bolivia 

Chojilla area . . . . . . . . . . . . . . . . . . do. 

Grey River . . . . . . . . . . . . . . . . . . . Newfoundland 

Hamme district . . . . . . . . . . . . . . . . North Carolina 

Isla de Pinos . . . . . . . . . . . . . . . . . . Cuba 

Josefina . . . . . . . . . . . . . . . . . . . . . Argentina 

Karni . . . . . . . . . . . . . . . . . . . . . . . Bolivia 

Los A vestruces . . . . . . . . . . . . . . . . Argentina 

Los Condores . . . . . . . . . . . . . . . . . do. 

Montredon . . . . . . . . . . . . . . . . . . . France 

Needle Hill. . . . . . . . . . . . . . . . . . . Hong Kong 

Oakleigh Creek. . . . . . . . . . . . . . . . Tasmania 

Panasqueira . . . . . . . . . . . . . . . . . . Portugal 

Pasto Bueno . . . . . . . . . . . . . . . . . . Peru 

San Martin . . . . . . . . . . . . . . . . . . . Argentina 

Storeys Creek . . . . . . . . . . . . . . . . . Tasmania 

Xihuashan 00 00 00 00 00 00 00 00 00 • China 

15 

2 

17 

7 

8 

16,5 

11 

3 

18 

3 

13 

4 

14 

19 

9,12 

3 

6,10 

20 

Sources of data for wolframite vein grade/tonnage model (table 2) 

1. Ahlfeld, Federico, and Schneider-Scherbina, Alejandro, 1964, Los 

yacimientos minerales y hidrocarburos de Bolivia: Bolivia Ministerio 

de Minas y Petroleo, Servicio Geologico, Bol. no. 5 especial, 388 p. 

2. Ball, T.K., Fortey, N.J., and Shepard, T.J., 1985, Mineralization at 

the Carrock Fell tungsten mine, N. England: Paragenetic, fluid 

inclusion and geochemical study: Mineralium Deposita, v. 20, p. 

57-65. 

3. Bundesanstalt fur Geowissenschaften und Rohstoffe, 1975, Argentina: Rohstoffwirtschaftliche Landerberichte, v. 10, 118 p. 

4. Davis, S.G., 1961, Mineralogy and genesis of the wolframite ore 

deposit, Needle Hill mine, New Territories, Hong Kong: Economic 

Geology, v. 56, no. 7, p. 1238-1249. 

5. Espenshade, G .H., 194 7, Tungsten deposits of Vance County, North 

Carolina, and Mecklenburg County, Virginia: U.S. Geological Survey 

Bulletin 948-A, p. 1-17. 

6. Financial Times, 1972, Mining international year book 1972-73: 

London, England, FT Business Publications Limited, 693 p. 

cassiterite, beryl, minor sulfide minerals, and lithiumbearing micas in quartz veins. Sulfide minerals, including 

pyrite, sphalerite, galena, and other sulfide minerals, as 

well as minor wolframite and cassiterite, are deposited in 

quartz veins during the sulfide stage. The late carbonate 

stage is characterized by minor amounts of tungsten- and 

tin-bearing minerals in fluorite-pyrite-carbonate-quartz 

veins. 

At the most famous tungsten mine in China, Xihuashan in the Dayu district, Jiangxi province, the orebodies 

occur as parallel sets of several hundred steeply dipping 

quartz veins across a 2.5-km distance (Tanelli, 1982). Each 

set or zone of quartz veins has economic mineralization 

over vertical ranges of 250 to 300 m and shows vertical 

zonation in ore and alteration mineralogy (Wu and Mei, 

1982). Wolframite is concentrated mostly in the middle to 

upper parts of the veins; sulfides are highest in the lower to 

J4 Contributions to Commodity Geology Research 

7. ---1986, Mining international yearbook 1986: Essex, England, 

Longman Group Limited, 547 p. 

8. Higgins, N.C., 1985, Wolframite deposition in a hydrothermal vein 

system-The Grey River tungsten prospect, Newfoundland, Canada: 

Economic Geology, v. 80, no. 5, p. 1297-1327. 

9. Hyde, D.M., 1983, The mineral industry of Peru: Mineral yearbook 

1981, v. 3, Area reports: International, p. 773-782. 

10. Kingsbury, C.J.R., 1965, Cassiterite and wolframite veins of Aberfoyle and Storeys Creek, in McAndrew, John, ed., Geology of 

Australian ore deposits: Commonwealth Mining and Metallurgical 

Congress, Australia and New Zealand, 8th, v. 1, Melbourne, 1965, 

p. 506-511. 

11. Li, K.C., and Wang, C.Y., 1955, Tungsten-Its history, geology, 

ore-dressing, metallurgy, chemistry, analysis, applications, and 

economics (American Chemical Society Monograph no. 94, 3d ed.): 

New York, Reinhold Publishing, 506 p. 

12. Malaga Santolalla, Fermin, 1954, El tungsteno en el Peru: Sociedad 

Geologica Del Peru, Bol. 27, 186 p. 

13. Pouit, Georges, and Fortune, J.P., 1980, Metallogenie comparee 

des Pyrenees et du sud du Massif Central-ltineraires geologiques, excursions dans "le Grand Sud-ouest," preparees dans le 

cadre du 26e Congres Geologique International: (Paris, Juillet 1980), 

Aquitaine, Languedoc, Pyrenees, Bulletin des Centres de Recherches Exploration-Production Elf-Aquitaine, Memoire no. 3, p. 

381-439. 

14. Register Australian Mining, 1981: Leederville, Western Australia, 

Lodestone Press Pty Ltd., p. 190. 

15. Salpeteur, 1., 1985, Geochemical dispersion from the Bir Tawilah 

wolfram-quartz veins in the pediplain of Saudi Arabia: The Institution of Mining and Metallurgy, Prospecting in Areas of Desert 

Terrain, p. 141-154. 

16. U.S. Bureau of Mines, Calculated cumulative deposit production 

from mineral data canvass. (Individual records on microfilm files are 

proprietary.) 

17. Valasco, Pablo, 1985, The mineral industry of Bolivia, in U.S. 

Bureau of Mines; Minerals yearbook 1983, v. 3, Area reports-International: Washington, D.C., U.S. Government Printing Office, p. 

111-120. 

18. Willig, C.D., and Delgado, J., 1985, South America as a source of 

tungsten, in Primary Tungsten Association: Madrid, Spain, International Tungsten Symposium, 3d, 36 p. 

19. Proprietary data. 

20. Estimate by author. 

middle sections; and calcite and fluorite are most abundant 

in the lower parts. Alteration varies from predominantly 

potash feldspathization in the lower parts to predominant! y 

greisenization in the upper parts of each vein. 

The grade/tonnage model of wolframite-bearing 

quartz veins has been built with data from 19 deposits (table 

2). Although the deposits are distributed worldwide, China 

is represented by only one deposit even though it has the 

largest number of important deposits of this type. Data for 

many of the deposits include reserves, resources, and past 

production. Ninety percent of the deposits contain at least 

60,000 t of ore, half contain at least 680,000 t, and 10 

percent contain at least 7.7 million t (fig. 2). Figure 2 also 

presents the distribution of tungsten grades for wo3 in the 

deposits. Ninety percent of the deposit grades exceed 0.5 

percent; 50 percent exceed 0. 8 percent; and 10 percent 

exceed 1.4 percent W03 • Lognormal distributions fit the 
1.0 

(/) EXPLANATION 1- 0.8 U5 0 Deposit 0 

c.. 

w 

0 0.6 u. 

0 

z 

0 0.4 i= 

a: 

0 

Q.. 

0 0.2 a: 

Q.. 

0.0 

0.01 0.1 1.0 10.0 100.0 

MILLION METRIC TONS ORE 

1.0 

(/) 

1- EXPLANATION 

0.8 U5 

0 0 Deposit Q.. 

w 

0 0.6 u. 

0 

z 

0 0.4 i= 

a: 

0 

Q.. 

0 0.2 !f 

0.0 

0.25 0.40 0.63 1.0 1.6 2.5 

GRADE (PERCENT W03

) 

Number of 

Variable deposits in 90% 50% 10% 

the model 

Ore tonnage, in 

million metric tons 19 0.06 0.68 7.7 

Average weight 

percent wo3 19 0.52 0.81 1.4 

Figure 2. Grade-tonnage model for quartz-wolframite vein 

deposits. 

observed distributions of tonnage and grade well. The 

correlation coefficient (r= -0.45) shows a marginally significant inverse correlation between grade and tonnage at a 

5-percent significance level. 

PORPHYRY TUNGSTEN-MOLYBDENUM 

DEPOSITS 

Porphyry or stockwork tungsten-molybdenum deposits (Hobbs and Elliott, 1973) represent another class of 

deposit; studies have been published on only a few of this 

type. Deposits that have been described include the Mount 

Pleasant deposit, New Brunwick, Canada (Parrish, 1982); 

the Logtung deposit, Yukon territory, Canada (Noble and 

others, 1984); the Y angchuling deposit, Jiangxi province 

People's Republic of China (Yan and others, 1980); and 

Xingluokeng, Fujian province, People's Republic of China 

(Liu, 1982). 

The Xingluokeng, Yangchuling, and Logtung deposits include scheelite, wolframite, and molybdenite as disseminated grains, in veins and veinlets, and in breccia pipes 

in or above epizonal granitic rocks. The deposits are 

associated with late phases of granodiorite to granite 

(monzogranite) stocks. The stocks are emplaced into 

contact-metamorphosed clastic sedimentary rocks. The 

deposits show several generations of mineralization. The 

main ore minerals are scheelite, wolframite, and molybdenite; bismuthinite, pyrrhotite, pyrite, sphalerite, arsenopyrite, galena, and chalcopyrite are also present. Alteration 

assemblages include K-feldspar, biotite, quartz, sericite, 

and montmorillonite (Yan and others, 1980; Liu, 1982; and 

Noble and others, 1984). 

The Fire Tower zone near Mount Pleasant consists of 

wolframite, molybdenite, native bismuth, sphalerite, arsenopyrite, chalcopyrite, stannite, and galena disseminated in 

brecciated rhyolite porphyry. The rhyolite porphyry, which 

changes gradationally with depth to microgranite, was 

emplaced into a quartz feldspar porphyry unit that probably 

contains both intrusive and extrusive rocks. The deposits 

are strongly zoned in terms of the metal content, mineralogy, and types of altered rocks (Parrish, 1982). 

Grade and tonnage data are available for deposits near 

Mount Pleasant (Parrish, 1982) and Logtung (Noble and 

others, 1984). Liu (1982) presents data on grades and 

physical dimensions of the Xingluokeng deposit. While 

these data are too few to construct a grade/tonnage model, 

they are adequate to obtain a rough idea of the magnitude of 

tonnages and grades for these deposits. These few data 

suggest porphyry tungsten-molybdenum deposits contain 

from a few tens of millions to a few hundreds of millions of 

metric tons of ore. Grades of W03 probably vary from 0.1 

to 0. 3 percent; grades of molybdenum probably vary from 

about 0. 0 1 to 0. 1 percent. 

DISCUSSION 

Mineral deposit and grade/tonnage models are useful 

aids in making decisions with regard to land classification, 

mineral exploration, and mineral availability. Figure 3 

shows three types of tungsten grade/tonnage domains 

derived from such models. For the tungsten skarns and 

wolframite-bearing quartz veins, the domain is defined by 

the mean plus and minus one standard deviation of the 

logarithms of grade and tonnage. These domains should 

contain about 45 percent of deposits of each type. The 

domain for porphyry tungsten-molybdenum deposits is an 

Tungsten-Grades and Tonnages of Some Deposits )5 
10 

OM 

3: 

1-

z 

w 

u 

a: 

w 

a.. 1 w 

(!) 

<( 

a: 

w 

> <( 

10 

0.1 

100 

10 

MILLION METRIC TONS ORE 

100 1000 

Figure 3. Grade and tonnage domains for tungsten skarn, 

wolframite-bearing quartz vein, and tungsten-molybdenum porphyry deposits. Domains for skarn and vein 

deposits are defined by the mean plus and minus one 

standard deviation of the logarithms of the grade and 

tonnage data. Domain for porphyry deposits is 

approximate. 

approximation based upon limited data. Figure 3 shows the 

slight differences between skarn and vein types and the 

greater differences between these types and the porphyry 

tungsten-molybdenum deposits. 

REFERENCES 

Bateman, P.C., 1965, Geology and tungsten mineralization of the 

Bishop district, California: U.S. Geological Survey 

Professional Paper 470, 208 p. 

---1982, Scheelite-bearing skarns of the east-central Sierra 

Nevada, California, U.S.A., in Hepworth, J.V., and Yu 

Hong Zhang, eds., Symposium on tungsten geology, Jiangxi, 

People's Republic of China, 1981, Proceedings: ESCAP/RMRDC, Bandung, Indonesia, p. 23-31. 

Einaudi, M.T., Meinert, L.D., and Newberry, R.J., 1981, Skarn 

deposits, in Skinner, B.J., ed., Economic Geology, 75th 

Anniversary Volume: p. 139-183. 

Hobbs, S.W., and Elliott, J.E., 1973, Tungsten, in Brobst, D.A. 

and Pratt, W.P., eds., United States mineral resources: U.S. 

Geological Survey Professional Paper 820, p. 667-678. 

Kelly, W.C., and Rye, R.O., 1979, Geologic, fluid inclusion, and 

stable isotope studies of the tin-tungsten deposits of 

Panasqueira, Portugal: Economic Geology, v. 74, p. 

1721-1822. 

Liu Wengzhang, 1982, Geological features of mineralization of 

the Xingluokeng tungsten (molybdenum) deposit, Fujian 

Province, in Hepworth, J.V., and Yu Hong Zhang, eds., 

Symposium on tungsten geology, Jiangxi, People's Republic 

of China, 1981, Proceedings: ESCAP/RMRDC, Bandung, 

Indonesia, p. 339-348. 

J6 Contributions to Commodity Geology Research 

Meinert, L.D., Newberry, Rainer, and Einaudi, M.T., 1981, An 

overview of tungsten, copper, and zinc-bearing skarns in 

western North America, in Silberman, M.L., Field, C.W., 

and Berry, A.L. eds., Proceedings of the symposium on 

mineral deposits of the Pacific Northwest: U.S. Geological 

Survey Open-File Report 81-355, p. 303-327. 

Menzie, W.D., Reed, B.L., and Singer, D.A., 1988, Grades and 

tonnages of some lode tin deposits, in Hutchinson, C.S., ed., 

Geology of tin deposits in Asia and the Pacific: Berlin, 

Springer-Verlag, p. 73-88. 

Morgan, B.A., 1975, Mineralogy and origin of skarns in the 

Mount Morrison pendant, Sierra Nevada, California: 

American Journal of Science, v. 275, p. 119-142. 

Mutschler, F.E., Wright, E.G., Ludington, Steve, and Abbott, 

J.T., 1981, Granite molybdenite systems: Economic 

Geology, v. 76, p. 874-897. 

Newberry, R.J., and Swanson, S .E., 1985, Granites associated 

with tungsten skarns, in, Taylor, R.P., and Strong, D.F., 

eds., Granite-related mineral deposits: Halifax, Nova Scotia, 

Canada, CIM, p. 197-199. 

Noble, S.R., Spooner, E.T.C., and Harris, F.R., 1984, The 

Logtung large tonnage, low grade W (scheelite)-Mo porphyry 

deposit, South-Central Yukon Territory: Economic Geology, 

v. 79, p. 848-868. 

Parrish, I.S., 1982, The Mt. Pleasant tungsten deposit, Canada, in 

Hepworth, J.V., and Yu Hong Zhang, eds., Symposium on 

tungsten geology, Jiangxi, People's Republic of China, 1981, 

Proceedings: ESCAP/RMRDC, Bandung, Indonesia, p. 

165-178. 

Reed, B.L, 1986a, Replacement Sn, in Cox, D.P., and Singer, 

D.A., eds., Mineral deposit models: U.S. Geological Survey 

Bulletin 1693, p. 61. 

---1986b, Sn veins, in Cox, D.P., and Singer, D.A., eds., 

Mineral deposit models: U.S. Geological Survey Bulletin 

1693, p. 70. 

---1986c, Sn greisen, in Cox, D.P., and Singer, D.A., eds., 

Mineral deposit models: U.S. Geological Survey Bulletin 

1693, p. 70. 

Reed, B.L., and Cox, D.P., 1986, Sn Skarns, in Cox, D.P., and 

Singer, D.A., eds., Mineral deposit models: U.S. Geological 

Survey Bulletin 1693, p. 58. 

Reed, B.L., Duffield, W., Ludington, S.D., Maxwell, C.H. and 

Richter, D.H., 1986, Rhyolite-hosted Sn, in Cox, D.P., and 

Singer, D.A., eds., Mineral deposit models: U.S. Geological 

Survey Bulletin 1693, p. 172. 

Streckeisen, A., 1975, To each plutonic rock its proper name: 

Earth-Science Reviews, v. 12, p. 1-33. 

Tanelli, G., 1982, Geological setting, mineralogy and genesis of 

tungsten mineralization in Dayu district, Jiangxi (People's 

Republic of China)-An outline: Mineralium Deposita, v. 

17' p. 279-294. 

Tischendorf, G. , 1977, Geochemical and petrographic 

characteristics of silicic magmatic rocks associated with 

rare-element mineralization, in Stemprok, M., Burnol, L., 

and Tischendorf, G. , eds. , Metallization associated with acid 

magmatism, v. 2: Prague, Czechoslovakia Geological 

Survey, p. 41-96. 

Wu Yongle, and Mei Yong Wen, 1982, Multi-phase intrusion and 

multi-phase mineralization in Xihuashan tungsten ore field, 

in Hepworth, J.V., and Yu Hong Zhang, eds., Symposium 
on tungsten geology, Jiangxi, People's Republic of China, 

1981, Proceedings: ESCAPIRMRDC, Bandung, Indonesia, 

p. 437-449. 

Yan Meizhong, Wu Yongle, and Li Chongyou, 1980, Metallogenetic systems of tungsten in southeast China and their 

mineralization characteristics, in Ishihara, Shunso, and Takenouchi, Sukune, eds., Granitic magmatism and related 

mineralization: Mining Geology Special Issue 8, p. 215-221. 

Tungsten-Grades and Tonnages of Some Deposits )7 

Chapter K 

Vanadium-Resources in Fossil Fuels 

By GEORGE N. BREIT 

U.S. GEOLOGICAL SURVEY BULLETIN 1877 

CONTRIBUTIONS TO COMMODITY GEOLOGY RESEARCH 

CONTENTS 

Abstract Kl 

Introduction Kl 

Production and Resources in Fossil Fuels Kl 

Petroleum Kl 

Coal K2 

Tar Sands K3 

Oil Shale K3 

Form of Vanadium K4 

Mechanisms of Vanadium Enrichment K4 

Summary K6 

References K6 

TABLES 

1. Range of vanadium abundances in petroleum from various locations K2 

2. Vanadium content of bitumen recovered from selected tar sands deposits K3 

3. Vanadium and oil content of selected oil shales K3 

Contents Ill 

Vanadium-Resources in Fossil Fuels 

By George N. Breit 

Abstract 

Significant amounts of vanadium are made available 

for commercial use as a byproduct of petroleum, while 

minor amounts are produced as byproducts of coal and oil 

shale. Depending on the future demand for fossil fuels, 

vanadium recovered from these sources could satisfy a 

substantial portion of the world's vanadium needs. 

Though the United States does not possess large 

resources of vanadiferous fossil fuels comparable to those 

in Venezuela, Australia, and Canada, vanadium contained 

in heavy oils in California and in oil shales in Montana and 

Kentucky may some day satisfy domestic needs. 

Vanadium is variably distributed in fossil fuels. It 

occurs as oil-soluble organic complexes, particularly porphyrins (tetrapyrroles), and in authigenic minerals. The 

vanadium content of fossil fuels is related to the origin and 

composition of the organic matter as well as depositional 

conditions and diagenetic history. The origin of vanadium 

and mechanisms of concentration are incompletely 

understood, though it seems likely that the interaction of 

seawater and terrestrial sediments surrounding depositional basins mobilized a portion of the metal incorporated into the organic material. 

INTRODUCTION 

In 1985, approximately one-half of the domestic 

vanadium requirement of the United States was satisfied by 

recovery of the metal as a byproduct of petroleum processing and consumption (Hilliard, 1987). The magnitude of 

this production highlights the potential of vanadium produced from oil and other organic-rich geologic materials. If 

the projected reliance on metal-rich oils is accurate (International Petroleum Encyclopedia, 1985), the amount of 

byproduct vanadium could increase dramatically. Approximately 10 percent of the world's vanadium resources are 

contained in tar sands and petroleum (Kuck, 1985). Future 

energy demands may favor worldwide development of oil 

shales and other presently uneconomic fossil fuel resources 

that contain large amounts of vanadium. 

In addition to petroleum, byproduct vanadium has 

been produced from the mining and beneficiation of iron, 

uranium, phosphate, and aluminum; in these deposits, the 

vanadium content rarely exceeds 1 percent. In the recent 

past, the demand for vanadium in the United States was 

satisfied largely by uranium ores mined on the Colorado 

Plateau. A large drop in the price of uranium closed most of 

these mines, forcing vanadium mills in the United States to 

rely on imported feedstocks, such as iron slags from South 

Africa and petroleum residues. Whereas most petroleum 

residues are from imported oils, development of some of the 

domestic heavy oil resources could satisfy a substantial 

portion of the United States' vanadium demand. 

This paper focuses on vanadium resources contained 

in petroleum, coal, tar sands, and oil shale. The evaluation 

includes a brief review of vanadium production from and 

resources in these materials, a discussion of the form of the 

metal, and speculation on the origin of the variable amounts 

of vanadium in these materials. This paper is not intended 

as a thorough review of vanadium resources in organic-rich 

geologic materials but as an introduction to the importance 

of these materials in projecting future vanadium supplies. 

The important problems related to recovering the vanadium 

contained in these materials are not addressed. 

PRODUCTION AND RESOURCES IN FOSSIL 

FUELS 

Petroleum 

Crude oils contain vanadium concentrations from less 

than 0.2 parts per million (ppm) to 1,400 ppm (table 1). The 

highest vanadium contents are generally associated with 

heavy oils, those having API gravity lower than 20°. Heavy 

oils also contain high abundances of sulfur and asphaltenes 

(Yen, 1975), which cause problems during refining (International Petroleum Encyclopedia, 1985). Decreasing supplies of lighter oils have favored production of these 

metal-rich oils, and refineries and oil production facilities 

have been designed to accommodate associated processing 

problems (Peer, 1981). 

Vanadium is recovered from oil by processing ash 

generated in thermoelectric power plants, petroleum coke 

residues generated during refining of heavy oils, and 

residues plated onto catalysts. An estimated 3,000 metric 

tons (t) of vanandium (10 percent of the world's vanadium 

Vanadium-Resources in Fossil Fuels K1 
Table 1. Range of vanadium abundances in petroleum 

from various locations 

[Data from Whisman and Cotton, 1971; Nelson, 1972; and Kuck, 1985] 

Location 

Abu Dhabi ............................... . 

Australia ................................. . 

Indonesia ................................ . 

Iran ..................................... . 

Israel .................................... . 

Libya .................................... . 

Mexico .................................. . 

Nigeria .................................. . 

North Sea ................................ . 

Venezuela ............................... . 

United States ............................. . 

Alaska ................................ . 

Arkansas .............................. . 

California ............................. . 

Louisiana .............................. . 

Mississippi ............................ . 

Oklahoma ............................. . 

Texas ................................. . 

Wyoming .............................. . 

Vanadium (ppm) 

<1-1.3 

<1-2 

<1 

16-150 

<1 

0.2-28 

10-80 

<1-4 

<1-19 

0.3-1,400 

<1-100 

<1-15 

<1-400 

<1-15 

<1-40 

<1-15 

0.01-15 

<1-110 

production) was recovered from these materials in 1985 

(Kuck, 1987). Most of this vanadium is produced by 

processing ash from powerplants. Recovery of vanadium 

from this material was started by Long Island Light Company in 1964 (Kuck, 1985). Refineries that process heavy 

oils concentrate the sulfur, refractory organic compounds, 

and metals in a residual petroleum coke that is sometimes 

burned to provide process heat for the refinery. The ash 

generated from burning the residue commonly contains as 

much as 8 percent vanadium. Primary vanadium is also 

recovered by reprocessing catalysts used in petroleum 

refining. Metals and refractory organic compounds plate on 

the catalysts until they amount to 50 percent of the weight 

of the catalyst and poison the active surfaces. This occurs 

even in refining oils that have low metal contents. Currently, facilities in Japan and Texas produce vanadium by 

reprocessing catalysts, and planned increases in capacity 

will add the capability of producing an additional2,300 t of 

vanadium per annum in the United States alone (Metals 

Week, 1986). 

Most of the ash and petroleum coke treated for the 

recovery of vanadium is from vanadium-rich Venezuelan 

oil. Kapo (1978) estimated that the amount of vanadium 

annually added to the environment as pollution from the use 

of Venezuelan oil is equivalent to the world's consumption 

of vanadium. Venezuela contains the majority of the 

world's heavy oil resources and also contains the largest 

resource of vanadium in petroleum, an estimated 10 million 

t (Kapo, 1978). While no oil fields of comparable extent 

contain the consistently high vanadium contents of the 

Venezuelan fields, oils with greater than 50 ppm vanadium 

K2 Contributions to Commodity Geology Research 

are produced in Iran and from several fields within the 

United States. All of these heavy oils are processed in order 

to remove the metals to a residual fraction prior to refining, 

hence beneficiating the vanadium. 

Within the United States most oils contain less than 

50 ppm vanadium, making them unlikely vanadium feedstocks, though residual ashes from burning even metal-poor 

oils commonly contain 20 weight percent vanadium 

(Hyden, 1961), and a few contain as much as 40 weight 

percent vanadium (Yen, 1975). Major heavy oil deposits in 

California and Alaska contain up to 400 ppm vanadium 

(table 1). The heavy oil fields of California contain an 

estimated 37 billion barrels, about 87 percent of the heavy 

oil resources of the conterminous United States (International Petroleum Encyclopedia, 1985). If half of the contained vanadium is recovered, 250,000 t of vanadium could 

be produced, enough to satisfy the domestic vanadium 

requirements for 50 years at our present rate of consumption. The heavy oil resources in Alaska are not defined 

enough to allow evaluation of their vanadium resources. 

Coal 

The world average vanadium content of coal is 25 

ppm (Valkovic, 1983). Vanadium abundances in ashes 

formed by burning coals generally range from 0.01 to 0.3 

weight percent (Abernathy and Gibson, 1963), though some 

ashes contain almost 8 percent (Reynolds, 1948). The lower 

values are typical for most common coals formed from 

subaerial plant material. However, by comparison, rare 

marine sapropelic (cannel) coals may contain more than 1 

percent vanadium in the raw coal (Zhang, 1985). 

China is the only producer of vanadium from coal. 

Sapropelic coals of Cambrian age in Changyang County, 

Hubei Province have produced vanadium since 1977 

(Wang, 1980). The extent of these deposits is unknown, but 

their development may have influenced China's entry into 

the world vanadium market as an exporter. In addition to 

the coals in China, sapropelic coal deposits in Venezuela 

contain high abundances of vanadium (Kapo, 1978). 

The average content of vanadium in coals in the 

United States is 20 ppm (Swanson and others, 1976). 

Values of most mined coal deposits are less than 100 ppm, 

though Maylotte and others (1981) describe the upper 

portion of a coal layer that contains up to 1, 800 ppm 

vanadium. As far as the author is aware, none of the major 

coal deposits of the United States contain vanadium abundances consistently high enough for them to be considered 

a vanadium resource. 

Vanadium-rich material burned as a substitute for 

coal in Peru and Argentina during World War II was 

actually asphaltite, a petroliferous residue. This resinous 

material occurs as a fracture filling and as layers in 

bituminous shales. Ash generated by burning this material 
Table 2. Vanadium content of bitumen recovered from 

selected tar sands deposits 

[Numbers in parantheses indicate the following references: (1) Peer, 1981; 

(2) Harrison and others, 1981; (3) Ondish and Suchanek, 1981; and (4) 

Martin and others, 1984] 

Vanadium 

(ppm) Location 

Canada 

Athabasca basin ........................ . 180-290(1) 

United States 

Northeastern Oklahoma ................. . 14 (2) 

Southern Oklahoma .................... . 200 (2) 

Uinta basin, Utah ...................... . 20-70 (1) 

Ulvalde, Texas ......................... . 126 (3) 

Southern Texas ........................ . 85 (4) 

contained up to 14 percent vanadium, but Kett (1948) 

determined that these deposits were small and too discontinuous to be mined economically solely for the production 

of vanadium. 

Tar Sands 

Asphaltite deposits, particularly tar sands, are substantial vanadium resources. Although no commercial facilities are producing vanadium from these deposits at present, 

plans have been prepared to recover vanadium by processing ash generated from one of the operations that recovers 

oil from the tar sands in Alberta, Canada (Northern Miner, 

1984). The tar sand deposits in Alberta are the world's 

largest and contain oil resources of 2 trillion barrels (Koch, 

1982). The bitumen in the tar sands contains about 250 ppm 

vanadium, whereas the ash formed during processing has a 

maximum of 2.5 percent vanadium. Estimates indicate that 

the proposed plant could produce 850 t of vanadium per 

year from the 33,000 t of fly ash generated in the production 

of 20 million barrels of oil (Northern Miner, 1984). Plans 

for vanadium plants at other tar sand operations in Alberta 

are under study. 

Measured and speculative tar sand resources in the 

United States contain about 53.7 billion barrels of bitumen 

(Lewin and Associates, 1984). The largest tar sand deposits 

occur in Utah, Alaska, Alabama, California, and Texas. 

Test production of bitumen has been done for several 

deposits (Marchant and Koch, 1982), though no recovery of 

contained metals has been described. The limited data on 

the vanadium contents of these bitumens indicate a range of 

values (table 2). The Uinta basin in Utah hosts the largest 

domestic tar sand deposits, about 20 billion barrels. However, the vanadium content of oil recovered from these 

deposits is low and is comparable to the content of the 

Eocene Green River Formation (table 3), the probable 

source rock. Deposits in California, Oklahoma, and Texas 

Table 3. Vanadium and oil content of selected oil shales 

[Numbers in parentheses designate the following references: (1) Tuttle and 

others, 1983; (2) Ingram and others, 1983; (3) Robl and others, 1983; (4) 

Desborough and others, 1981; (5) Derkey and others, 1985; (6) Glikson 

and others, 1985; (7) Lindner, 1983; (8) Mining Journal, 1974; and (9) 

Shirav and Ginzburg, 1983] 

Vanadium Oil content 

Oil shale (ppm) Fischer assay 

(gal/ton) 

United States: 

Green River Formation. 80 (1) 30 (2) 

Ohio Shale ........... 1,400 (3) 12 (3) 

Heath Formation ...... 25-8,000 (4,5) 10 (5) 

Australia: 

Rundle Formation .... 110 (6) 26 (7) 

Condor deposit .......... 100 (6) 18 (7) 

Toolebuc Formation ... 1,000-2,000 (6) 16 (8) 

Israel: 

Ghareb Formation ..... 110 (9) 16 (9) 

contain greater amounts of vanadium than the Utah deposits, although less than the Alberta tar sands. 

Oil Shale 

Vanadium contents of oil shales range from 25 to 

8,000 ppm (table 3). The highest vanadium contents are 

contained in marine deposits; this is the same relation 

observed in coal deposits. A plant in Nanjing, China, is the 

only reported producer of vanadium from residues of 

processed oil shale (Kuck, 1984). The feedstock for this 

plant probably originated from the extensive Fushun or 

Maoming oil shale deposits (Wang, 1980). Although vanadium is currently produced from only one plant, plans for 

the coproduction of this metal from oil shale have been 

considered for Devonian black shales in the Eastern United 

States (Chase, 1980; Leventhal and Kepferle, 1982), oil 

shales in Estonia (Mining Magazine, 1985), and the Toolebuc Formation, in Australia (Mining Journal, 1974). 

The vanadium resources of the Cretaceous Toolebuc 

Formation near Julia Creek, Queensland, Australia, are the 

world's largest such resources contained in oil shale, with 

average grades of 0. 2 percent vanadium in the shales 

containing the most oil. The deposit contains an estimated 4 

X 109 t of oil shale (Stewart, 1983), which may contain 8 X 

106 t of vanadium. Plans were prepared for the construction 

of a plant to produce 10,000 t of vanadium per year along 

with the oil (Mining Journal, 1974). 

The Mississippian Heath Formation in Montana and 

Devonian black shales in the Eastern United States have the 

greatest potential for the production of vanadium and other 

metals as byproducts of shale oil in the United States. The 

Green River Formation, the richest oil-shale deposit in the 

United States, is an unlikely producer since it has relatively 

low vanadium contents, < 100 ppm (Tuttle and others, 

Vanadium-Resources in Fossil Fuels KJ 
1983). The Heath Formation covers about 7,000 km2 of 

central Montana (Des borough and others, 1981). If 0.1 

percent of the vanadium in the Heath Formation were 

recovered, it would amount to 24,000 t of vanadium 

(Derkey and others, 1985). Devonian black shales including 

the Sunbury Shale, Ohio Shale, Chattanooga Shale, and 

others in the East-Central United States (Robl and others, 

1983) contain a huge volume of low-grade oil shale, 

although only a small percentage can be developed by 

near-surface mining. Estimates indicate that 8,000 t of 

vanadium could be produced annually from an operation 

processing 90 ,000 t of oil shale per day (Leventhal and 

Kepferle, 1982). 

The production of vanadium from oil shales is likely 

only if the oil shale is developed by mining as opposed to in 

situ methods. The form of the vanadium in the shales 

varies, and it may not be extractable by the in situ methods 

capable of extracting the oil. Thus, recovery of metals from 

oil shale will require processing the rock after the oil is 

extracted. 

FORM OF VANADIUM 

The recovery of vanadium from the organic-rich 

geologic materials depends on the compound in which the 

metal occurs and how it is bonded. Three valences of 

vanadium exist under natural conditions; V(V), V(IV), and 

V(III) (Wanty, 1986). The chemically reducing nature of 

humic materials enables them to reduce V (V) to V (IV) 

under most pH conditions (Szalay and Szilagyi, 1967). 

Consistent with these data, extensive electron spin resonance and other instrumental studies indicate that most of 

the vanadium in natural organic compounds, such as that 

contained in fossil fuels, is present as V02 + (Saraceno and 

others, 1961; Filby, 1975). The association of vanadium 

with organic material is due to favorable bonding characteristics of V02 + with functional groups containing nitrogen, oxygen, or sulfur. 

Vanadium in petroleum and tar sands is contained in 

an oil-soluble form including several different organic 

complexes, but porphyrins (tetrapyrroles) are the most abundant (Yen, 1975). The proportion of vanadium in petroleum 

contained in the porphyrin compounds is uncertain, but 

estimates range from 60 to 100 percent (Speight, 1980; 

Spencer and others, 1982; Crouch and others, 1983; Fish 

and Komlenic, 1984; Goulon and others, 1984). The 

porphyrins are altered molecules of chlorophyll or hemoglobin that originated in plants and animals (Baker and 

Louda, 1981). Four nitrogen ligands in the center of the 

porphyrin molecule bond with the vanadium forming a very 

stable complex. The stability of the structure enables it to 

resist breakdown at temperatures as high as 300 oc and 

under conditions of near-surface weathering (Lewan, 

1980). Apparently, the vanadium porphyrins are bound to 

K4 Contributions to Commodity Geology Research 

larger organic molecules characterized as asphaltenes 

(Baker and Louda, 1981), hence the metals concentrate 

with the refractory compounds during refining. 

In oil shales and coal, vanadium also occurs in 

porphyrins and other organic complexes, including oxygenrich compounds (Maylotte and others, 1981). The association of vanadium with oxygen-rich functional groups is 

consistent with epigenetic enrichment described in the 

following section. In addition to organic complexes, vanadium occurs in silicates, sulfides, and oxides. Vanadium 

minerals are probably the result of changes during diagenesis in which some vanadium moved from sites in the 

organic compounds into forming authigenic phases. One of 

the vanadiferous authigenic minerals in coal (Finkelman, 

1981) and oil shale is roscoelite, a vanadiferous mica. Other 

authigenic phases include sulvanite (Cu3VS4) (Fan, 1983) 

and an unidentified iron-vanadium-titanium oxide (Desborough and Poole, 1983). 

MECHANISMS OF VANADIUM ENRICHMENT 

Vanadium is uniformly distributed throughout the 

Earth's crust; most rocks contain between 20 and 250 ppm. 

The high vanadium content in certain fossil fuels implies 

that processes that favored the accumulation of some 

organic material also favored the concentration of vanadium 

or that vanadium was extracted from migrating ground 

waters during diagenesis. However, many otherwise similar 

accumulations of organic matter lack high vanadium contents. Thus, understanding the processes and conditions 

under which vanadium is enriched could aid in identifying 

vanadium resources. 

The vanadium content of fossil fuels was apparently 

acquired from an aqueous phase because the lithic components of the coal, oil shale, and petroleum source rocks have 

normal abundances of vanadium. The accumulation could 

have occurred during the growth of the organisms that were 

precursors to the organic matter, by selective extraction of 

vanadium by particles settling through the water column, or 

from pore waters during diagenesis. Solutions that may 

have provided the vanadium include seawater, meteoric 

ground water, and volcanic exhalations. 

Vanadium enrichment in petroleum and coal has been 

considered epigenetic, the result of interaction between the 

organic accumulations and circulating waters (Elder, 1973). 

Heavy oil is generally considered to have been altered by 

biodegradation of "normal" petroleum (Tissot and Welte, 

1984). The biodegradation is enhanced by the through flow 

of oxygenated ground waters, whicb. may have also supplied the vanadium. Experimental studies, however, have 

shown that vanadium is not adsorbed by petroleum 

(Gulyayeva and Lositskaya, 1968). In addition, the constant 

V/Ni ratio in petroleum and source rocks indicates that the 

vanadium content was controlled by the source rocks and, 
hence, by the depositional environment (Lewan, 1980). On 

the other hand, a portion of the vanadium in many coal 

deposits accumulated largely by interaction with ground 

water. Zilbermintz (1935) attributed the high vanadium 

contents of coals in the Ural Mountains to waters transporting vanadium that was weathered from mafic massifs 

containing vanadiferous magnetite deposits. The interaction 

of the coal macerals with the oxygenated ground waters 

resulted in the oxidation of the organic matter, which then 

adsorbed the dissolved vanadium, bonding it to the coal. 

With the exception of coal, most of the vanadium in fossil 

fuels accumulated during deposition of the organic precursors. Therefore, this discussion emphasizes characteristics 

of environments where organic matter accumulated. 

A notable characteristic of the most vanadium-rich oil 

shales, petroleum accumulations, and coals, is that they are 

or were derived from deposits composed mostly of marinederived organic matter. This restriction implies that seawater, the composition of marine organic matter, or indigenous organisms were somehow essential to the 

accumulation of vanadium. The influence of the composition of the organic matter and the abundance of vanadium 

were examined by Lewan (1980), who determined that the 

highest contents are associated with deposits that were 

originally plankton or algae, organisms abundant in a 

marine environment. 

Plankton may have accumulated vanadium during 

their life cycle, particularly because phytoplankton contain 

abundant chlorophyll, the likely precursor of the porphyrins 

common in fossil fuels. Vanadium contents of plankton 

average 25 ppm (Knauss and Ku, 1983). Therefore, accumulations containing 500 ppm vanadium could form simply 

by loss of 95 percent of the organic constituents of the 

plankton. If these organisms were the pathway of metal 

accumulation, certain metals should be selectively concentrated because of biochemical selectivity in the living 

organisms. Instead, a comparison of the abundance of 

metals in organic-rich shales with the concentration of 

metals in seawater suggests enrichment factors are constant, 

independent of the metal considered (Holland, 1979). 

The presence of vanadium in porphyrins restricts the 

probable conditions in which the organic matter could have 

accumulated and therefore is an indicator of the depositional 

environment of the host sediments. The porphyrins were 

most likely formed by modification of chlorophyll as it 

settled through the water column and during diagenesis 

(Baker and Louda, 1981). Chlorin, a demetallated form of 

chlorophyll (magnesium is removed) is relatively abundant 

in marine sediments deposited in anoxic conditions (Baker 

and Louda, 1981). In aerated seawater, these compounds 

decompose rapidly. This fact implies that much of the water 

column overlying the deposits was anoxic or that the 

organic matter settled through the water column very 

rapidly, before oxidation could occur. Baker and Louda 

( 1981) also concluded that chelation of vanadium by porphyrins may not occur until shallow burial. This finding 

most likely indicates that vanadium was initially bound to 

the sediments by adsorption and weak complexes and was 

later redistributed during early diagenesis. 

Other organisms known to concentrate vanadium, up 

to 5 percent on a dry weight basis, are members of the order 

Tunicata (Glikson and others, 1985). These sessile, benthic 

creatures may have once been abundant in the ocean, but it 

is doubtful that they could have survived in the anoxic 

conditions ambient during the deposition and preservation 

of the organic matter, and therefore they are unlikely as the 

sole accumulators of vanadium. Nevertheless, abundant 

tunicate fossils have been observed in the vanadium-rich 

coals in China (Zhang, 1985). 

Adsorption to particle surfaces is considered the 

major mechanism of vanadium removal from seawater 

(Amdurer and others, 1983). Adsorption processes are 

particularly effective in environments where V(V) (the 

dominant valence in aerated waters) is reduced to V (IV), as 

observed in an estuarine environment (van der Sloot and 

others, 1985). Anoxic conditions favoring the preservation 

of porphyrins would be sufficiently reducing to convert 

V(V) to V(IV). Thus the accumulation of organic matter 

under an at least partially anoxic water column may have 

been required for preferential accumulation of vanadium. It 

is notable that several recent marine deposits of organic 

matter, composed mainly of plankton remains, are not 

particularly enriched in metals including vanadium (Nissenbaum and Swaine, 1976). The low vanadium content of 

these recent sediments may indicate that the overlying water 

columns were not sufficiently reducing or that vanadium 

actually accumulates by diffusion of bottom waters through 

the sediment over relatively long periods (Lewan, 1980). 

Holland (1979) argued that the relatively constant 

enrichment factor of metals (including vanadium) in carbonaceous marine shales favored accumulation directly 

from normal seawater. The present concentration of vanadium in seawater is about 0.002 ppm (Riley and Taylor, 

1972). To concentrate the vanadium in a layer of sediment 

to 1,000 ppm, a column of water at least 1 x 106 times the 

thickness of the layer is required. Therefore, waters that 

formed oil shales in shallow, restricted basins, such as the 

Heath Formation and the Toolebuc Formation (less than 50 

m deep), either contained higher abundances of vanadium 

or were subject to the circulation of large volumes of water. 

The latter seems unlikely considering that both units were 

deposited in restricted basins. 

Some researchers have suggested that the vanadium 

was supplied by volcanic exhalations on the sea floor. This 

concept is consistent with the observed vanadium enrichment near ocean ridges (Hodkinson and others, 1986; 

Marchig and others, 1986). Bostrom and Fisher (1971) 

examined the variation in vanadium abundance in the Indian 

Ocean and concluded that volcanogenic and terrestrial 

sources of vanadium were important. Nevertheless, a subVanadium-Resources in Fossil Fuels K5 
marine volcanogenic source for all vanadium-rich fossilfuel accumulations is precluded by those accumulations that 

formed in restricted, shallow basins, apparently isolated 

from hydrothermal vents. 

Not all marine deposits are enriched in vanadium 

(several oil shales and some petroleums of marine origin 

contain relatively low vanadium contents), implying that 

secondary controls within the marine environment are also 

important. For example, the Toolebuc Formation in Australia and the Ghareb Formation in Israel have substantially 

different vanadium contents (table 3) even though both were 

deposited in shallow cratonic basins during the Cretaceous. 

In addition, oils recovered from Miocene rocks in California (150 ppm V) and Venezuela (350 ppm) have significantly different vanadium contents. Both of these oils are 

heavy (API less than 20°), and although they have other 

compositional differences, the difference in vanadium 

abundances is particularly striking. 

The variation in the vanadium abundance may be 

related to differences in the composition of the rocks 

surrounding the basin. Kapo ( 1978) suggested that the high 

vanadium content in Venezuelan oil and coal was due to a 

source in surrounding uplands. Wedepohl (1964) proposed 

that metals enriched in the bituminous shales of the Kupferschiefer originated from the dissolution of iron oxides in the 

red bed units surrounding the sea. Hite (1978) similarly 

proposed that the evaporation of seawater and the interaction of the resultant brines with clastic deposits resulted in 

a metal-rich brine that enriched the Permian Phosphoria 

Formation (locally a low-grade oil shale) in metals, including vanadium. 

Fossil fuels having high vanadium contents have been 

deposited in variable amounts throughout geologic time; 

therefore, it is unsatisfying to explain the variation in the 

vanadium content of these deposits as the result of changes 

in the composition of seawater. The amount of vanadium is 

also apparently unrelated to specific depositional settings 

because carbon-rich rocks deposited in geosynclines, in 

cratonic basins, and in shelf environments all have high 

vanadium contents in some locations. As shown in this 

discussion, factors that controlled the vanadium contents of 

fossil fuels are poorly understood. 

SUMMARY 

Production of vanadium from fossil fuels will depend 

heavily on the type of materials developed to meet the 

world's future energy needs. Large resources of vanadium 

are contained in the heavy oil deposits in Venezuela, coal in 

China, oil shale in Australia, and tar sands in Canada. In the 

United States, heavy oil deposits in California and possibly 

those in Alaska are the most likely fossil-fuel accumulations 

capable of producing substantial amounts of vanadium in 

the future. Low-grade oil shale deposits in Montana and 

K6 Contributions to Commodity Geology Research 

Kentucky could produce large amounts of vanadium, but 

their development seems unlikely. 

Vanadium is contained in fossil fuels as oil-soluble 

organovanadium compounds and in minerals. The oilsoluble vanadium in petroleum can be concentrated by 

normal processing, generating a residue amenable for vanadium recovery. In oil shales and in coal, vanadium is also 

contained in minerals. The mineral residence of vanadium 

in oil shale will limit recovery of the metal by any in situ 

method of oil production. 

The mechanisms that cause vanadium to accumulate 

in fossil fuels are not well understood. The highest abundances occur in fossil fuels that originated as organic-rich 

deposits in a marine environment. Evidence strongly suggests that the type of organic matter, chemical conditions in 

the overlying water column, and interaction of seawater 

with clastic sediments may have been significant with 

regard to the accumulation of vanadium. 

The drop in the price of crude oil in the mid-1980's 

slowed development of more expensive, vanadium-rich 

fossil fuels described in this paper. However, projections of 

future demand indicate that these resources will be developed. Therefore, vanadium produced from fossil fuels 

including petroleum, tar sands, coal, and oil shale should be 

considered in any long-term evaluation of vanadium supplies. 

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Desborough, G.A., Poole, F.G., and Green, G.N., 1981, Metalliferous oil shales in central Montana and northeastern 

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Comparative study of oil shales and shale oils from the 

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Lewin and Associates, Inc., 1984, Major tar sand and heavy oil 

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Lindner, A. W., 1983, Geology and geochemistry of some Queensland Tertiary oil shales, in Miknis, F.P., and McKay, J.F., 

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Metals Week, 1986, Catalyst reclaimers are hot property: Metals 

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Mining Journal, 1974, Queensland oil shale venture: Mining 

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Nissenbaum, Arie, and Swaine, D.J., 1976, Organic matter-metal 

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Northern Miner, 1984, Recovery of vanadium from oil sands 

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