Mercury and Other Trace Elements 

In Sphalerite and Wallrocks 

From Central Kentucky, Tennessee 

And Appalachian Zinc Districts

GEOLOGICAL SURVEY BULLETIN 1251-F

Mercury and Other Trace Elements 

In Sphalerite and Wallrocks 

From Central Kentucky, Tennessee 

And Appalachian Zinc Districts

By JANICE L. JOLLY and ALLEN V. HEYL

CONTRIBUTIONS TO ECONOMIC GEOLOGY

GEOLOGICAL SURVEY BULLETIN 1252-F

A discussion of the mercury, cadmium, 

germanium, gallium, and strontium 

content of sphalerite from ore deposits of 

the Central and Eastern United States

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1968
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

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

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

Page

Abstract ________________.._______________ Fl

Introduction ___________________________ 2

Acknowledgments ___________________ 3

Methods of analysis ______________________________. 4

Mercury in sphalerite ______________________________. 5

Cadmium, germanium, and gallium in sphalerite ____________. 15

Mercury in other ores _____________________________ 21

Mercury in other minerals ____________________ 22

Mercury in wallrock _____________________ 22

Conclusions _________________________________ 26

References cited _______________________ 27

ILLUSTRATIONS

Page

FIGURE 1. Map showing mineral districts in Central and Eastern 

United States from which mercury-bearing samples 

were obtained ______________________ . F6

2. Diagram showing mineral paragenesis in the central Kentucky mineral district ____________ _ - 12

3. Sketch of Faircloth mine adit showing location of limestone samples and amount of mercury _ 24

TABLES

Page

TABLE 1. Mercury content of sphalerite from Central and Eastern

U.S. mineral districts ____________________ F7

2. Complete semiquantitative spectrographic analyses of 

selected sphalerites from the central Kentucky, central 

Tennessee, and other mineral districts _____ . 16

3. Average germanium and gallium content of sphalerites 

from the central Kentucky mineral district showing 

distribution by zone and stage of mineral distribution _. 19

4. Variance of mercury content in a suite of limestone

samples from the Faircloth vein, Woodford County, Ky _. 23

5. Mercury content of limestone wallrock from the Hoover

vein, shaft 1, Cannon County, Tenn _____ - 23

6. Mercury content of a wallrock suite along a thinned, altered, and silicified limestone bed of a major ore body 

in the Mascot-Jefferson City belt, east Tennessee 25

III

CONTRIBUTIONS TO ECONOMIC GEOLOGY

MERCURY AND OTHER TRACE ELEMENTS IN

SPHALERITE AND WALLROCKS FROM

CENTRAL KENTUCKY, TENNESSEE, AND

APPALACHIAN ZINC DISTRICTS

By JANICE L. JOLLY and ALLEN V. HEYL

Abstract

Sphalerite samples collected from the central Kentucky and central Tennessee districts and from a selection of other mineral deposits in the Central 

and Eastern United States contain anomalous amounts of mercury. Mercury 

is present as an integral part of sphalerite in amounts ranging from 100 to 

300,000 parts per billion. Sphalerites from central Kentucky, central Tennessee, and from one locality in North Carolina contain the most mercury. 

Sphalerites from east Tennessee, other Appalachian Valley, and Upper 

Mississippi Valley zinc districts contain less mercury than those from central 

Kentucky, central Tennessee, and several eastern hydrothermal vein and 

massive sulfide deposits in metamorphic rocks.

The sphalerites of the central Kentucky and central Tennessee vein districts contain notable amounts of cadmium, germanium, and gallium, which 

along with mercury may possibly be recovered by smelters if sphalerites are 

mined in the future. These sphalerites also contain strontium, whereas this 

element is lacking in sphalerites analyzed from other districts. Sphalerites of 

the Appalachian Valley contain less germanium and cadmium than do those 

of the central Kentucky and central Tennessee veins. Even so, the cadmium 

content is relatively high in all sphalerites analyzed as compared with the 

content of those from other mineralized regions in the United States and 

Canada. Except for higher mercury content, sphalerites collected from Triassic border-zone deposits in Pennsylvania and Connecticut are similar in 

trace-element content to the Appalachian Valley sphalerites, whereas the 

higher temperature New England vein and massive sulfide sphalerites, which 

contain 5 to 10 percent iron, either completely lack or contain very little 

germanium or gallium.

Scattered preliminary analyses show that several minerals, soils, and wallrocks in mineral deposits in Central and Eastern United States also contain 

anomalous mercury. The mercury content of wallrock at the Faircloth vein 

in central Kentucky, at the Hoover vein in central Tennessee, and at a major 

ore body in the Mascot-Jefferson City belt of east Tennessee suggests the 

presence of detectable mercury leakage anomalies; such anomalies may be 

used effectively in prospecting for lead-zinc deposits.

Fl
F2 CONTRIBUTIONS TO ECONOMIC GEOLOGY

INTRODUCTION

This paper describes in detail the first published occurrences of 

mercury in mineral deposits east of the Mississippi River. Until 

recently mercury was never considered a significant trace element 

in the lead and zinc deposits of the Central and Eastern United 

States. Preliminary observations on mercury in central Kentucky 

and central Tennessee sphalerites were presented by us (Jolly and 

Heyl, 1966) in a paper given at the 1964 Southeastern Section 

meeting of the Geological Society of America at Nashville, Tenn. 

The present paper is a product of research by members of the 

U.S. Geological Survey on the mineral deposits of the Central and 

Eastern United States from 1960 to 1967. The sphalerite and 

wallrock specimens analyzed were collected by Alien V. Heyl, 

Janice L. Jolly, and Maurice Brock in 1960, 1962, 1964, 1965, and 

1966.

Only a few authentic natural occurrences of mercury east of the 

Mississippi River were known in 1964. Mercury was reported in 

a prospect adit near Vienna, Mo. (Roscoe Smith, oral commun., 

1964), sampled by the U.S. Geological Survey and assayed by the 

U.S. Bureau of Mines. A channel sample of the face contained 

0.01 to 0.005 percent mercury. W. S. White (oral commun., 

1964), in checking a report of mercury associated with native 

silver in Michigan, had two samples analyzed from White Pine, 

Mich. The two samples of native silver contained 0.44 percent 

(98.5 percent silver) and 0.27 percent (68.5 percent silver) 

mercury.

Nearly all the other reported occurrences of mercury in the 

Central and Eastern United States are unsubstantiated, or the 

mercury in the occurrences is probably of artificial origin. There 

are a few unsubstantiated reports of metallic mercury placers in 

Michigan and along the Ohio River in the literature of the early 

1800's (Cleaveland, 1822, p. 552). Free mercury in clay was reported by C. B. Strow in a freshly dug basement in Kanawha 

County, W. Va. Subsequent examination by the U.S. Bureau of 

Mines (written commun., 1942) revealed the presence of 

calomel (?) and cinnabar (?); one sample of clay assayed as much 

as 0.3 percent mercury. Samples 10 feet away, however, contained 

no mercury. The reason for this local accumulation of mercury is 

not known, and its presence here as a natural occurrence was 

subject to much debate. Native mercury also was reportedly 

found in a basement in Nashville, Tenn. (R. A. Laurence, oral 

commun., 1964). Probably both of these last two occurrences are
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F3

of recent human origin from some unexplained sources of waste 

mercury.

The absence of naturally occurring minerals such as cinnabar, 

metacinnabar, and calomel north and east of Arkansas may reflect 

the deep erosion of rocks and ore deposits and the greater age of 

the mineral deposits in this area than in those to the west. All 

mercury reported in this paper is in the form of trace amounts in 

minerals or in wallrocks of ore deposits.

Mercury has long been used as a geochemical prospecting tool 

(Hawkes and Webb, 1962; Saukov, 1946; Williston, 1964). Case 

histories of prospecting on the basis of anomalous trace concentrations of mercury have been published in the U.S.S.R. (Saukov, 

1946; Vershkovskaya, 1956; Fursov, 1958; Ozerova, 1959) a,nd 

recently in the Western United States where similar methods have 

been utilized (Brokaw and others, 1962; Friedrich and Hawkes, 

1966). The recent development of more precise methods of 

measurement, accurate to 1 to 2 ppb (parts per billion) mercury, 

is certain to make mercury even more valuable as an indicator 

of base-metal ores.

Mercury is not commonly considered as a potential byproduct 

where it occurs as a minor element in lead-zinc deposits. At 

Langpele mine, Sweden, however, mercury is currently recovered 

from sphalerite that commonly contains 0.1 to 0.2 percent mercury. Chiefly a lead-zinc district, Langpele is nevertheless one of 

the largest sources of mercury in the world (Erland Grip, oral 

commun., 1966; Gavelin, 1955, p. 823).

ACKNOWLEDGMENTS

The assistance of many individuals in the preparation of this 

study is gratefully acknowledged. Members of the Kentucky 

Geological Survey and the Tennessee Division of Geology and 

R. A. Doyle, State Geologist of Maine, were of particular help. 

The assistance of Douglas Black, M. R. Brock, A. R. Taylor, 

Richard Lewis, W. E. Hall, R. A. Laurence, George Simmons, J. 

D'Agostino, D. Cox, and Helmuth Wedow of the U.S. Geological 

Survey, as well as many private company geologists, especially 

from the New Jersey Zinc Co., American Zinc Co., Dennison 

Mines, Ltd., Callahan Mining Co., Tri-State Zinc Co., OzarkMahoning Co., and Eagle Picher Co., was of great value. The 

special efforts of Joseph Dinnin and Helen Worthing of the 

U.S. Geological Survey in developing new and more accurate 

chemical and spectrographic methods of analysis were notably 

helpful in the success of the study.
F4 CONTRIBUTIONS TO ECONOMIC GEOLOGY

METHODS OF ANALYSIS

Special refinements were made in each method of analysis used, 

which included wet chemical (Dinnin and Worthing, 1966), 

atomic absorption, and special spectrographic procedures. Agreement (table 1) between different methods of analysis on the same 

sample was good for some samples and poor for others. The 

reasons for this are the many difficulties encountered in handling 

mercury-bearing sulfides, as well as variable limits of sensitivity 

between methods. Although the technical aspects of analytical 

methods are not an objective of this paper, some problems inherent in mercury analysis should be mentioned.

Most important to any method is the recognition of the relation 

of the mercury to its host mineral. Fryklund and Fletcher (1956, 

p. 227), Stoiber (1940), and Friedrich and Hawkes (1966) have 

considered mercury as among the elements likely to substitute for 

part of the sphalerite lattice. Our information also indicates 

that the mercury in sphalerite of these districts is held in the 

lattice. It is probably incorporated by coprecipitation and does 

not occur as a separate included or intergrown mineral such as 

cinnabar or metacinnabar. Several reasons for this conclusion 

areas follows:

1. No mercury minerals are known in the districts.

2. X-ray diffraction traces showed the presence of not two but 

one mineral that has sphalerite structure.

3. No foreign mineral was observed in microscope examination of 

slides and polished sections.

4. Microchemical tests of the coarsely crushed but not powdered 

sphalerite did not free any mercury but were negative, as expected if the mercury was a part of the lattice.

Fryklund and Fletcher (1956) and Oftedal (1940) indicated 

that mercury as a component of natural sphalerite reacts differently to the spectroscopic arc as compared with mercury in the 

compound mercuric sultfide mixed into a synthetic standard. The 

mercury held in the sphalerite lattice is less volatile and burns 

longer, presenting a problem to accurate spectroscopic analysis.

Friedrich and Hawkes (1966) also recognized the inherent 

difficulties in analyzing sulfides and probably many rock-forming 

silicates for mercury. On this problem they stated: "* * * mercury 

substitutes for other elements and therefore can be extracted only 

after destruction of the lattice. The tightly bound mercury in 

these minerals is released much more slowly and at a variable 

rate." After destruction of the lattice, Friedrich and Hawkes used
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F5

a gold filter trap as an extra step in their method of analysis to 

avoid this problem.

Variant results for two separate handpicked parts of the same 

sample may also indicate that the mercury is not evenly distributed throughout the mineral. The amount of grinding in sample preparation and the conditions under which the sample is 

stored also might attribute to a variant assay. Mercury has been 

detected evaporating from recently ground sphalerite samples 

(F. N. Ward, oral commun., 1965). Such losses by leakage can be 

held at a minimum only if the sample is ground immediately 

prior to analysis. Without these special precautions, mercury 

analyses of suMdes such as sphalerite probably should be regarded as semiquantitative.

Mercury fulminate, used in blasting caps and certain other 

explosives, is another possible major source of contamination of 

samples from fairly recent mines (W. H. Callahan, oral commun., 

1966) and from roadcuts in which the chemical is used for explosives. Unusual care should be taken to obtain unfractured clean 

samples with entirely fresh surfaces to minimize such contamination.

MERCURY IN SPHALERITE

Mercury has been reported in sphalerite from several sources, 

many of which were compiled by Fleischer (1955) in a paper on 

minor elements in some sulfide minerals. In Europe, mercury has 

been reported in sphalerite from Austria (Schroll, 1950-51; 

1953); Bohemia (Kutina, 1958; Yak, 1951); France, the 

Mediterranean area, and northern Africa (De Launay and 

Urbain, 1910); Spain (Pina de Rubies and Lopez de Azcona, 

1937); Norway (Oftedal, 1940); and Sweden (Gabrielson, 1945).

Sphalerite that contains mercury has also been reported from 

the Soviet Union (Saukov, 1946). Fursov (1958) described a 

mercury anomaly derived from oxidation of mercury-rich 

sphalerite and galena. The mercury was considered an "isomorphous admixture," in both ore and wallrock, as no mercury 

sulfides were known in the deposit. Ozerova (1959) in the Karatu 

district also reported mercury aureoles around lead-zinc deposits 

derived from mercury-bearing sphalerite, galena, tetrahedrite, 

and barite. Ozerova (1959, p. 799) concluded that mercury is 

present probably as a "diadochic substitute" in all minerals.

In the United States, mercury has been reported as a minor 

element in sphalerite from the Coeur d'Alene district of Idaho
F6 CONTRIBUTIONS TO ECONOMIC GEOLOGY

(Fryklund, 1964; Fryklund and Fletcher, 1956); Leadville, Colo. 

(Bartlett, 1889); and Cripple Creek, Colo. (Eckel, 1961). In the 

Coeur d'Alene district, mercury substitutes for zinc in amounts 

from 0.005 to 0.02 percent and averages 0.0095 percent. Other 

than tetrahedrite, which contains less than 0.01 percent mercury, 

no other mercury-bearing1 mineral is known in that district 

(Fryklund and Fletcher, 1956, p. 227). At Cripple Creek, Cdo.,

50 100 150200 MILES

1. Tri-State

2. Central Missouri

3. Southeast Missouri

4. Kentucky-Illinois

5. Central Tennessee

6. Cumberland River

7. Central Kentucky

8. Upper Mississippi Valley

9. East Tennessee

10. Southwest Virginia

11. Ducktown, Tenn.

12. Linville Falls, N.C,

13. Timberville, Va.

14. Friedensville, Pa.

15. Shawangunk, N.Y.

Large Small

Mineral district

and number

Mineral districts

16. White Pine, Mich.

17. Pembroke, Maine

18. Cherryfield, Maine

19. Blue Hill (Black Hawk, 

Callahan), Maine

20. Madison mine, New Hampshire

21. Bristol Copper, Conn.

22. Phoenixville, Pa.

23. Bamford mine, Pennsylvania

24. Almedia mine, Pennsylvania

25. Ancram mine, New York

26. New London quarry, Maryland

27. Virginia Piedmont deposits

28. Serpent Mound, Ohio

29. Angel Station, Ala.

FIGURE 1. Mineral districts in Central and Eastern United States from 

which mercury-bearing samples were obtained.
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F7

one small specimen suggests the complete replacement of a 

sphalerite crystal by cinnabar.

Analyses of 76 sphalerite samples from mineral districts in the 

Central and Eastern United States show anomalous mercury 

content (table 1). Figure 1 shows the location of these mineral 

districts. Mercury occurs in amounts ranging from 100 to 300,000

TABLE 1. Mercury content of sphalerite from Central and Eastern U.S.

mineral districts

[Number in parentheses after mine or district name indicates index number shown in fig. 1. 

Letter in parentheses following the mercury analysis vaflue indicates separate parts of handpicked specimens ; letter may be repeated under the separate analytical methods, indicating 

a split of the same part of a specimen. Spectrographie analyses: N.D., none detected 

(less than 5,000 ppb) ; <5,000, between 4,000 and 4,999 ppb]

Mercury content, in parts per billion

Location and description Wet Spectrp- Atomic

chemical graphic absorption

analyses l analyses 2 methods 3

Appalachian Valley zinc districts

Pennsylvania:

Uberroth mine, Priedensville (14), Lehigh 

County, Beekmantown Group 

Massive gray sphalerite _ _ _ N.D. ________

Bamford zinc mine (23), Lancaster County, 

Kinzers Formation 

Gray sphalerite __________________- 15,000 _____ 

Almedia mine (24), Columbia County, in 

Devonian dolomite

Brown sphalerite _______________ _______ 5,000 _ _ 

Virginia:

Bowers-Campbell mine (13), Rockingham County, 

Beekmantown Dolomite 

Dark sphalerite ______ 100

Bowers-Campbell mine (13), Rockingham County, 

Beekmantown Dolomite

Yellow sphalerite _________________ __ N-D- _______

Old Timberville mine (13), Rockingham County, 

Beekmantown Dolomite

Yellow sphalerite __________________ _______ 7,000 ________

Ivanhoe mine (10), Austinville district, Wythe 

County

Brown sphalerite _________________ 1,100 _______ _ _ 

Arcadia zinc mine (10), Scott County, Kingsport 

dolomite

Black sphalerite __________________ _______ 5,000 ________

Myers prospect (10), Smyth County, Beekmantown Dolomite

Yellow sphalerite _________________ _______ <5,000 _ _

East Tennessee:

Mascot mine (9), Knox County, Kingsport 

Formation 

Dark-banded sphalerite ___________ N.D. ________

Yellow sphalerite ______________ ____ N.D.

Young mine (9), Jefferson County, Kingsport 

Formation 

Yellow sphalerite _________________ ______ N.D. ________

New Jersey Zinc Jefferson City mine (9), 

Jefferson County, Kingsport Formation 

Yellow sphalerite __________________________

Flat Gap mine (9), Hancock County, Kingsport _______ 5,000 ________

Formation

Dark colloform sphalerite ____________ _______ N.D. ______

Yellow sphalerite __________________ ______ N.D. ________

Very pale yellow sphalerite _________ ______ N.D. ________

New Prospect mine (9), Union County, Maynardville Limestone Member

Colloform yellow <Iark gray sphalerite _ N.D. ________

Shiloh prospect (9), Hawkins County, Kingsport 

Formation

Orange-yellow sphalerite __________ - 5,000 ________

See footnotes at end of table.
F8 CONTRIBUTIONS TO ECONOMIC GEOLOGY

TABLE 1. Mercury content of spfialerite from Central and Eastern U.S. 

mineral districts Continued

Mercury content, in parts per billion

Location and description Wet Spectrpchemical graphic 

analyses 1

Atomic 

absorption 

methods 3

Appalachian Valley zinc districts Continued 

East Tennessee Continued

Ballard mine, Sweetwater (9) district, Monroe 

County, Kingsport Formation

Pale-yellow sphalerite ______________ ___ - 5,000 __________

Jackson mine, Embreeville (9) district, Washington County, Shady Dolomite

Brown sphalerite ______________ 5,000 __________

North Carolina:

Linville Falls prospect (12), McDowell County, 

Shady Dolomite

Bluish-gray sphalerite ______________ 300,000 _________

Mississippi Valley mineral districts 

Central Tennessee:

Hoover vein (5), Cannon County, Carters Lime8 oTrk sphalerite ___________________ 390 (a) 350 (b) 

Red-orange sphalerite _______-__ 700 _________

Red-orange sphalerite _______ - 300 __________

Oakley vein (5), Wilson County, Carters Limestone

Dark sphalerite in second-stage barite 12,500 (a) __________

3,500 (b) _ __________

Holt vein (5), Williamson County, Carters 

Limestone

Dark sphalerite __________________ 30,000 __________

Vickers vein (5), Dekalb County, Catheys 

Limestone

Dark sphalerite _________________- 300,000 _________

Central Kentucky:

Zone 1: Allender vein (7), Woodford County

First-stage dark sphalerite ____ 300 N.D. ___ 

First-stage dark sphalerite ____ 300 (a) 500 (b) 

Second-stage yellow-black sphalerite _ 24,500 (a) __________

28,000(b) _______ _______

130,000 (c) _______ ______I 

Second-stage yellow-black sphalerite _ 170,000 __________

Zone 2: McChord vein (7), Fayette County

Second-stage yellow-black sphalerite _ 500 _______ 1,800 

Zone 3: Camp Pleasant vein (7), Franklin 

County 

Yellow-black sphalerite ________ 7,800 (a) ____

8,100 (b) 30,000 (b) __________

Georgetown quarry vein (7), Scott 

County

Yellow-black sphalerite ________ 17,800-

18,000 (a) _______ __ _____

 . . , 37,500 (b) 100,000 (b) 6,500 (c) 

Grata vein (7), Cox prospect, Henry 

County

Second-stage yellow-black sphalerite _ 170,000 __________

Grata vein, Ohio shaft, Owen County

Second-stage yellow-black sphalerite _ 180,000(a) 200,000(b) 

Grata vein, Twin Valley mine, Owen 

County

First-stage yellow-black sphalerite _ 1,000(a)

1,100 (b) _______ ~ 425 (c) 

Second-stage yellow-black sphalerite _ 120,000 

Milner vein (7), Woodford County

Second-stage yellow-black sphalerite _ 1,000 5,000 

Purdy vein (7), Bourbon County

Second-stage yellow-black sphalerite _ 1,000 (a) _______ 250 (b) 

Third-stage red-orange sphalerite __ 200 (a) _______ 450 (b)

Illinois-Kentucky fluorspar district 

Southern Illinois:

Oxford mine (4), Cave-In-Rock, Hardin County

Brown sphalerite __________________ _______ _______ 20,000 

Deardorf mine (4), Cave-In-Rock, Hardin 

County 

Dark-brown sphalerite ______________ _______ __ _ _ 100
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F9

TABLE 1. Mercury content of sphalerite from Central and Eastern U.S. 

________________mineral districts Continued

Mercury content, in parts per billion

Location and description Wet Spectrp- Atomic

chemical graphic absorption

analyses J analyses 2 methods 3

Upper Mississippi Valley district 

Northern Illinois:

Bautsch mine (8), main shaft-pitch, Galena, 

Jo Daviess County

Brown sphalerite __________________ ______ __________ 250

Amelia mine (8), Galena, Jo Daviess County

Reddish-brown sphalerite __________ ____ ______ 150

Wisconsin:

Old Dodgeville mine (8), Dodgeville, Iowa County

Sphalerite _______________________ ______ _______ 300 

Hoskins mine (8), New Diggings, Lafayette 

County

Sphalerite _______________________ _______ _______ 425 

Belmont Mound (8), Iowa County

Sphalerite in Silurian limestone _________ ___ 1,000 

Thompson-Temperly mine (8), New Diggings, 

Lafayette County

Sphalerite _______________________ ______ 100 

Piquette No. 2 mine (8), Tennyson, Grant 

County 

Sphalerite _______________________ ______ ____ 700

Tri-State district 

Oklahoma:

Blue Goose mine (1), Cardin, Ottawa County, 

1,200 feet from trough 

Sphalerite _____________________ -______ ________ 1,000

Webber mine (1), north of Picher, Okla., in 

Cherokee County, Kans. 

Sphalerite _______________________ _______ ____-__ 650

Maine sulfate districts 

Maine:

Dolsan Mines Ltd., Pembroke, Washington 

County, Ellsworth Schist 

Discovery pit (17), Pb-Zn veins in diabase

Black sphalerite ________________ _______ _______ 40,000 

Spanish pit (17), Pb-Zn veins in fractured 

diabase and agglomerate

Black sphalerite ________________ _ 34,000 

Big Hill pit (17), Zn-Pb-Ag veins in 

fractured volcanic agglomerate

Black sphalerite ________________ - 5,400 

Cherryfield prospect (18) (Cu, Pb, Zn, Ag), 

Washington County, Ellsworth Schist 

Veins in sheared diabase

Black sphalerite ________________ ____ 5,400 

Callahan mine (19) (Cu, Zn, Pb), Hancock 

County, Ellsworth Schist

Massive red sphalerite and chalcopyrite in 

talc schist

Red sphalerite _________________ _____ 5,400 

Black Hawk mine (19) (Cu, Zn, Pb, Ag, Au), 

Hancock County, Ellsworth Schist

Massive sphalerite zone in fragmental

quartzite ^ 

Black sphalerite ______________ __ 32,000

New England Pennsylvania veins 

New Hampshire:

Madison mine (20) (Pb, Zn), Carroll County 

Mineralized fracture zone in granite of White 

Mountain Plutonic-Volcanic Series

Dark-brown sphalerite ________ 11,000 

Connecticut:

Bristol Copper mine (21), Hartford County, 

Triassic Newark Group

Brown sphalerite ______________ 30,000 

Pennsylvania:

Wheatley mine (22), Phoenixville district, Chester 

County, Wissahickon Formation

Pb-Zn veins in gneiss and pegmatite and

Brown sphalerite _______________ ______ 20,000 (a) 17,000 (b)
F10 CONTRIBUTIONS TO ECONOMIC GEOLOGY

TABLE 1. Mercury content of splwlerite from Central and Eastern U.S. 

mineral districts Continued ___

Mercury content, in parts per billion

Location and description Wet Spectrp- Atomic

chemical graphic absorption

analyses 1 analyses 2 methods 3

New England-Pennsylvania, veins Continued 

New York:

Ancram Ag-Pb mine (25), Dutchess County

Black sphalerite ___________________ _______ 70,000 ________ 

Otisville Pb mine (15), Orange County, Shawangunk Conglomerate

Brown sphalerite __________________ _______ 50,000 __________

Virginia-Maryland Piedmont deposits 

Maryland:

New London marble quarry (26), Frederick 

County, Wakefield Marble

Gray sphalerite ___________________ _______ 10,000 _______ 

Virginia:

Dumfries mine (27), Louisa County, Wissahickon 

Formation 

Black sphalerite ___________________ _______ 15,000 __________

Valzinco mine (27), Spotsylvania County, 

Wissahickon Formation 

Black sphalerite __________________ _______ <5,000 __________

Armenius mine (27), Louisa County, Wissahickon 

Formation

Black sphalerite __________________ _______ 30,000 __________

Serpent Mound and other Ohio deposits 

Ohio:

Serpent Mound (28), Adams County, Silurian 

and Devonian dolomite 

Yellow sphalerite __________________ _______ N.D. __________

Smith quarry, Highland County, Greenfield 

Dolomite Member of Silurian age

Pale-brown sphalerite ______________ ______ <5,000 __________

1 By special procedures (Dinnin and Worthing, 1966) ; U.S. Geol. Survey analyst, J. I. 

Dinnin, 1964, 1965, and 1966.

2 By special procedure (Dinnin and Worthing, 1966) ; U.S. Geol. Survey analyst, H. W. 

Worthing, 1965.

3 U.S. Geol. Survey analyst, J. H. McCarthy, 1964; W. W. Janes, 1967.

ppb in the sphalerites of these districts. Most of the samples 

given in table 1 contain mercury well above the average background values for limestone and sandstone wallrock. A few of the 

samples are listed as mercury not detected, below 5,000 ppb 

mercury, which is the lower limit of detection for the specially 

adapted spectrographic method used. The central Kentucky, 

central Tennessee, and McDowell County, N.C., sphalerites contain the highest amounts detected. The sphalerites of the Wisconsin lead-zinc district and those collected in the east Tennessee, 

Virginia, and Pennsylvania Appalachian Valley zinc-mineral districts contain the lowest amounts detected. Although the Linville 

Falls, N.C., deposit is normally considered part of the Appalachian Valley zinc deposit group, the large amount of mercury in 

the sphalerite may be an indication that the deposit is anomalous 

to the group and that it may not have the same genesis. Likewise,
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES Fll

the lack of significant mercury in the Serpent Mound structure, 

Ohio, sphalerites indicates they are not related to the nearby 

central Kentucky mineralization.

In the central Kentucky district, where the mineral paragenesis 

and zoning (fig. 2) is well established (Jolly and Heyl, 1964), it 

was possible to collect a few specimens to represent each stage 

and zone. The ore deposits of the central Kentucky district have 

a districtwide lateral zoning in a concentric pattern. Within each 

zone three or four stages of mineral deposition occur. Near the 

middle of the district, two centers of fluorite-calcite dark 

sphalerite veins are designated Zone 1. Surrounding these centers 

is a much larger Zone 2, in which nearly all the veins contain 

fluorite, barite, calcite, and yellow-black sphalerite. Galena is 

absent or present in only minute quantities in both Zones 1 

and 2. In Zone 3, barite, galena, and sphalerite are the principal 

minerals; fluorite is absent, or present only in traces. Textures of 

the mineral veins change from bands of course comb crystals in 

Zone 1 to mostly colloform bands in the outer zones. The mineral 

paragenesis (fig. 2) throughout the district is constant and traceable, although the relative abundance of minerals varies from 

vein to vein.

Fourteen sphalerite samples collected from the central 

Kentucky mineral district contain 200 to 200,000 ppb mercury. 

More than half the samples contain amounts greater than 8,000 

ppb, and five contain more than 100,000 ppb (0.01 percent). 

This preliminary selection indicates that the highest values of 

mercury are in the second-stage yellow-black sphalerites of all 

zones. In contrast, the mercury values of the first and third stage 

dark and red sphalerites are much lower.

Sphalerites from the mineralized areas of eastern Tennessee all 

contain 5,000 ppb mercury or less. Sphalerites collected from the 

Jefferson City mine, Ballard mine, and Jackson mine contain 

5,000 ppb mercury, but less is indicated for the yellow and dark 

sphalerites from the Mascot, Flat Gap, and New Prospect mines. 

The analyzed sphalerites from the Appalachian Valley zinc deposits of Virginia also contain less than 5,000 ppb mercury. Black 

sphalerite from the Arcadia mine, Scott County, Va., contains 

5,000 ppb mercury. The five samples from the Wisconsin mineral 

district contain 1,000 ppb mercury or less.

Preliminary analyses of sphalerite-bearing ores from other 

Appalachian Valley zinc districts and a few nearby districts
F12 CONTRIBUTIONS TO ECONOMIC GEOLOGY

Il

;>-,£, ac

'2

&

.B i ,al

M

l

i i

i ill!!
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F13

suggest that mercury is rather abundant in some of the 

sphalerite. The districts in which mercury was detected include:

Faber mine, Albemarle County, Va.

Roanoke, Roanoke County, Va.

Osborn mine, Cresswell, Russell County, Va.

Ducktown, Polk County, Tenn.

Angel Station, Calhoun County, Ala.

Shawangunk mine, Sullivan County, N.Y.

Guymard mine, Orange County, N.Y.

For comparison, sphalerites from several higher temperature 

mineral deposits were also analyzed. These included (see table 1) 

sphalerites from the massive sulfide deposits of eastern Maine and 

Virginia and the hydrothermal mineralized veins of New Hampshire, Connecticut, Pennsylvania, New York, and Maryland. The 

amount of mercury detected in these sphalerites ranges from 

5,000 to 70,000 ppb. It would appear that most sphalerites of 

hydrothermal origin in the Central and Eastern United States 

contain anomalous mercury as a trace element and that deposition 

need not have been at low temperature. Deposits that are generally presumed to have magmatic affiliations have sphalerites that 

contain between 1 and 10 percent Fe (see table 2).

That sphalerites in central Kentucky, Tennessee, and other 

Appalachian Valley zinc districts as well as sphalerites in massive sulfide and other known high-temperature hydrothermal 

deposits contain mercury in any amount greater than normal 

background is of general significance to geochemical prospecting. 

These analyses are presented here to illustrate the strong 

possibilities of finding mercury anomalies in overlying soils and 

wallrock, which can be useful in locating blind ore deposits in 

most of the Eastern United States lead-zinc districts. Further 

sampling may also show that some districts, such as in central 

Kentucky and North Carolina, contain sufficient mercury in 

sphalerites to warrant its recovery as a byproduct.

The presence of mercury as an integral part of sphalerite precludes the supposition that it is the result of a more recent addition by replacement or by pore-space filling. Mercury was 

probably deposited from the original ore solution, coprecipitating 

with zinc in the cubic zinc sulfide lattice. In this way, the precipitating mineral "scavenges" (Hawkes, 1957) traces of certain 

elements from solutions a.nd incorporates them into the crystal 

lattice. In central Kentucky and central Tennessee, the zinc sulfide that contains the mercury is sphalerite, as established by Xray, and not wurtzite.
F14 CONTRIBUTIONS TO ECONOMIC GEOLOGY

The presence of mercury as an integral trace element in 

sphalerite suggests that the deposits are hydrothermal (warm 

water) in origin. Mercury may be transported in ore solutions as 

a complex ion in slightly alkaline sulfide solutions, as the volatile 

chloride, or as a mercury vapor (Krauskopf, 1951). The solubility of mercuric sulfide in pure water (pH 7) at 25°C is 

1X10~17 grams per liter and at 400°C is 3xlO~15 (Verhoogen, 

1938). It also has been reported (Hawkes and Webb, 1962) that 

when mercury vapor comes in contact with cool ground water, it 

condenses and cannot move through permeable material that is 

saturated with water. This fact indicates that pure cool water is 

incapable of carrying much mercury in solution.

Most workers (Tunell, 1964; Krauskopf, 1951) agree that the 

temperature of alkaline ore solutions depositing mercuric sulfide 

must be low, not as low as 80°C, nor as high as 250°C. Krauskopf 

(1951) stated that mercuric sulfide cannot exist in any system 

above 250°C that includes moving vapors without high concentrations of mercury or sulfur. It is also doubtful that mercury 

can exist as a complex sulfide ion in solutions at such temperatures. At temperatures where other sulfides precipitate, mercuric 

sulfide is unstable, so that its components are forced to travel to 

a cooler region before the compound can form. Even so, in deposits where mercuric sullfide is not a predominant constituent, it 

seems evident that mercury can be incorporated or scavenged by 

other precipitating sulfides (such as tetrahedrite and sphalerite) 

at a much higher temperature. With further study on the geochemistry of mercury as a minor component of minerals such as 

sphalerite, mercury may prove useful as a low-temperature geothermometer. Mercury is an element with normally limited 

physicochemical and temperature capacities, and it seems Mkely 

that the reasons for its presence, as well as amount present, as a 

minor element in other minerals will also show definable limitations.

The available geologic and geochemical data suggest (Jolly 

and Heyl, 1964) that the central Kentucky veins were deposited 

at temperatures less than 120°C. Edwin Roedder (written commun., 1967) has studied fluid inclusions in seven samples of 

fluorite and sphalerite from five mines of the central Kentucky 

district. They were found to be very similar to the fluid inclusions 

in most other deposits of the Mississippi Valley type. All 125 inclusions believed to be primary had freezing temperatures below 

 10°C (as low as 25°C), indicating concentrated brines containing approximately 15 to 35 weight percent salts. A small
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F15

group of primary inclusions in the outermost zone of several of 

the fluorite crystals contained considerably less concentrated 

brines, in the range of 5 to 10 weight percent salts. Although no 

homogenization experiments were run, all the inclusions contained small bubbles, indicating low temperatures of formation.

The geochemical data recently provided by Hall and Friedman 

(1963) from minerals in the Kentucky-Illinois district suggest by 

analogy that the ore-bearing solutions in central Kentucky and in 

central Tennessee were heated connate brines, probably mixed 

with minor quantities of magmatic brines. Districtwide zoning of 

minerals in a concentric pattern of three established zones (Jolly 

and Heyl, 1964) also affords critical evidence of heat that was 

supplied from a possible magmatic source centered deep beneath 

the Lexington and the Nashville domes. Higher temperatures of 

deposition in the central Kentucky district are indicated by the 

abundance of fluorite, dark sphalerite, and comb textures of 

veins (which are characteristic of epithermal ore deposits) in the 

central Zone 1 and by their absence in the outer two zones.

CADMIUM, GERMANIUM, AND GALLIUM IN SPHALERITE

The sphalerites of the central Kentucky and central Tennessee 

lead-zinc-barite-fluorite veins also contain notable amounts of 

cadmium, germanium, and gallium (table 2), which along with 

mercury should be considered as potential byproducts at the 

smelters, should these veins be mined in the future. In 37 semiquantitative spectrographic analyses representing a complete 

range of sphalerite from all zones in central Kentucky, the 

average cadmium content is 1.34 percent, the average gallium is 

0.009 percent, and the average germanium is 0:028 percent. The 

average cadmium content of six sphalerite specimens from 

central Tennessee is 1.3 percent, average gallium is 0.015 percent, 

and average germanium is 0.02 percent.

According to Warren and Thompson (1945), the average 

cadmium content of sphalerites of eastern Canada, Newfoundland, Greenland, and the Eastern United States is less than 0.30 

percent; that of sphalerites of the Western United States and 

Mexico is 0.43 percent. The maximum cadmium content in sphalerite reported (Campbell, 1959) is 2.1 percent in Sardinia. 

Stoiber (1940) stated that the 0.01 to 0.1 percent gallium, which 

is typical of ma*ny of the central Kentucky sphalerites, is higher 

than any European analyses and most other sphalerites of the 

Mississippi Valley type. The principal domestic source of ger-
F16 CONTRIBUTIONS TO ECONOMIC GEOLOGY

TABLE 2. Complete semiquantitative spectrographic analyses of selected

mineral

[Analyses by J. Harris and H. Worthing,

Sample Si Al Fe Mg Ca Ti Mn Ag Ba

Central Kentucky

1 CK-323A 0.01 0.002 0.3 0.002 0.2 0.0003 0.002 

2 A1-106A .001 .001 .3 .001 .1 0 .0003 

3 TL-94B .007 .003 .2 .0015 .03 .0005 .0002 

4 Cumb 210 .7 .001 .2 .02 .07 .003 .0005 

5 Boyle-1 .01 0 .1 .005 .003 0 0

0.0003 

.0001 

.00005 

.0002 

0

0.1 

1.5 

.15 

.3 

.0006

Central Tennessee

6 Hoov-64-1 .01 .001 .5 .001 .001 0 .0001 

7 Oak-64-100 .001 .001 .5 .001 .1 0 .0007 

8 K-64-100A .7 .001 .15 .02 .3 .003 .0002

0 

0 

0

.015 

.5 

.015

Kentucky-Illinois

9 WH-59-74A 0 0 4.2 0 0 0 .002 

10 WH-59-53 0 0 1.2 0 0 0 .002

.0002 

.0002

.0002 

.0002

East Tennessee

11 FG-10 .07 .001 .3 .015 .100 

12 T-12 .1 .001 .3 .001 .01 0 0

.0002 

.007

.0003 

.0003

North Carolina

13 LF-60-1 .03 .001 1 .07 .1 0 .001 .0015 .0003

Maine

14 BLK-106-66 2 .02 10 1 .05 .007 .2 

15 BH-206-66 2 <.001 10 .01 .1 0 .3 

16 IP-106A-66 .3 <.001 7 .02 .07 0 .3 

17 Sul-200-66 1 .01 5 .007 .005 .007 .02

.0007 

.07 

.02 

.1

.0003 

.0005 

.0003 

.001

New England and Pennsylvania veins

18 Mad-100-66 .15 <.001 1.5 .002 .002 0 .15 

19 Bris-100-66 .15 <.001 .7 .003 .003 0 .01 

20 W-201-66 .02 <.001 1 .0015 .001 0 0

1 Mercury analyses are excessive owing to procedures, used. 

2 Mercury was detected in these samples by other methods of analysis. See 

l.Faircloth vein ; Stage 1, Zone 1, dark sphalerite. 

2. Allender vein; Stage 2, Zone 1, dark sphalerite. 

3. Gratz vein ; yellow-black sphalerite, Stage 2, Zone 3. 

4. Cumberland River vein ; Stage 3, Zone 3, red sphalerite. 

5. Diagenetic light-colored ZnS, Boyle Dolomite, Panola quadrangle, Kentucky. 

6. Hoover vein, dark sphalerite. 

7- Oakley vein, dark sphalerite. 

8- Knight vein, red-yellow sphalerite. 

9- Hutson mine, Kentucky, dark sphalerite. 

10. Deardorff mine, Illinois, sphalerite. 

11- Flat Gap mine, Hancock County, yellow sphalerite. 

12. Jefferson City mine, Jefferson County, yellow sphalerite.

.0002 

.0001 

.0002

table 1.

.0005 

.0003 

.0003
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES FIT

sphalerites from the central Kentucky, central Tennessee, and other 

districts

U.S. Geol. Survey. Values are in percent]

Cd Cu Ge Hgi Ni Pb Sr Ga Co Mo Sn In

Central Kentucky

0.5 0.5

2.0 .3

2.0 .5

2.0 .3

.2 .05

0.03 0

.05

.03 1

.1 0

0 0

0

3

0

0

0

0.2

0015 .2

.07

.1

0

0.01

.05

.02

.007

.001

0.02 0

.01 0

.03 0

.02 0

.002 0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Central Tennessee

2.0 .15

2.0 .1

.7 .2

.02 20

.01

.05 0

0

.3 0

0

.007

.2

.007

0

.01

.0007

.01 0

.005 0

.02 0

0

0

0

0

0

0

0

0

0

Kentucky-Illinois

.64 0

.38 0

.004 0

.039 0

0009 .17

.0004 .002

0

0

.012 .0024

.004 <.0004

0

0

0

0

0

0

East Tennessee

.7 .02

1 .05

.002 0

.002 20

0

0

0

.01

0

0

.0007 0

.007 0

0

0

0

0

0

0

North Carolina

.7 .03 0 20 0 0 0 .0015 .002 0 0 0

Maine

1 .02

1 1

1 .07

2 .3

.0007 20

0 20

0 20

0 0

0

0

0

0

.05

.1

.02

.5

0

0

0

0

.0007 0

0 .01

0 .02

.0002 0

.0015

0

0

0

0

0

0

 

0

0

0

New England and Pennsylvania veins

1 .015

2 .07

1 .03

0 20

.005 20

.01 20

0

0

0

.003

.01

.02

0

0

0

.015 0

.007 .02

.0015 .001

0

0

0

0

0

0

.0015

0

0

l.S.Liriville Falls, McDowell County, sphalerite.

14.Black Hawk mine, Hancock County, massive sphalerite zone in fragmental quartzite, black 

sphalerite.

15. Big Hill pit, Pembroke, Washington County, veins in fractured volcanic agglomerate, 

black sphalerite.

16. Spanish pit, Pembroke, Washington County, veins in fractured diabase, black sphalerite.

17. Sullivan mine, Hancock County, veins in micaceous schist, dark sphalerite.

18. Madison mine, Carroll County, N.H., mineralized fracture zone in granite of White 

Mountain Plutonic-Volcanic Series, dark-brown sphalerite.

19.Bristol copper mine, Hartford County, Conn., minor sphalerite with copper ore in 

Newark Group along Triassic fault zone, brown sphalerite.

20.Wheatley mine, Phoenixville, Chester County, Pa., veins in fractured gneiss and pegmatite 

of Wissahickon Formation along Triassic border zone, brown sphalerite.
F18 CONTRIBUTIONS TO ECONOMIC GEOLOGY

manium is the Tri-State zinc-lead district of Missouri, Kansas, 

and Oklahoma, where germanium is extracted from sphalerite 

concentrates containing 0.01 to 0.015 percent germanium, less 

than half the average germanium content of the central Kentucky 

and central Tennessee sphalerites.

Ivanov (1964) reported that high-temperature skarn-type leadzinc deposits and low-temperature silver deposits have the most 

cadmium-rich sphalerites. Next are low-temperature lead-zinc 

deposits; intermediate-temperature sulfide deposits have the least. 

His data confirm, however, that the behavior of cadmium in ore 

formation is much more complex than one of simple temperature 

relationship. Cadmium in sphalerite at low temperatures, for instance, has an inverse relation to the concentration of chloride 

ions in solution, which explains the cadmium-lean ores associated 

with hydrothermal solutions derived from mafic magmas that are 

rich in chlorine. Cadmium may be enriched in ores deposited in 

carbonate rocks and in the presence of fluorite. Ivanov concluded 

that both the temperature of crystallization of sphalerite and the 

degree of concentration of cadmium in the hydrothermal ores 

determine the concentration of cadmium in ores; the effect of 

metallogenetic provinces on the concentration of cadmium in ores 

is considerable. Other workers, such as Badalov and Enikeev 

(1959), Warren and Thompson (1945), and Graton and Harcourt 

(1935), have indicated that cadmium in sphalerite increases as 

the temperature of ore formation decreases, so that its maximum 

content results in the lowest temperature sphalerites.

Our information (see examples in table 2), gathered from 

many analyses in a variety of mineral districts, indicates that 

most sphalerite from the Central and Eastern United States has 

a relatively high cadmium content as compared with other United 

States and Canadian districts, regardless of the temperature of 

deposition. High cadmium content in the epigenetic central Kentucky and central Tennessee sphalerites is most probably a result 

of its availability in a metallogenic province comparatively high 

in cadmium rather than a result of temperature as the principal 

controlling factor. The difference between the cadmium content 

of central Tennessee and central Kentucky sphalerites and the 

comparatively lower cadmium content of east Tennessee 

sphalerites may also be a reflection of temperature, but it is 

difficult to carry this type of comparison further.

The average cadmium content of eight sphalerites from Zone 

1, Stage 1, of central Kentucky is 1.2 percent, slightly lower than
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F19

the district average (37 specimens) of 1.34 percent cadmium. 

Diagenetic sphalerites (example in table 2), however, collected 

from concretions and sedimentary fractures in the southern 

part of the central Kentucky district contain very small amounts 

of cadmium and gallium and are virtually free of germanium. 

The low values for these three elements in the diagenetic 

sphalerite refute the hypothesis of high cadmium in all lowtemperature sphalerites a,nd provide useful tools to distinguish 

these diagenetic sphalerites from the more common epigenetic 

sphalerites in the veins of the same district.

Germanium is generally supposed (Stoiber, 1940, p. 518; 

Fleischer, 1955, p. 993) to be most concentrated in sphalerites 

where the temperatures of formation are lowest. Graton and 

Harcourt (1935), Stoiber (1940), and Warren and Thompson 

(1945) also agree that gallium is a common minor constituent 

in low-temperature varieties of sphalerite.

As mentioned above, the cold-water diagenetic sphalerites of 

central Kentucky are virtually free of germanium (seven samples 

analyzed contained none) and low in gallium (seven samples 

contained an average of 0.001 percent). Table 3 shows preliminary germanium and gallium data for the epigenetic 

sphalerites in central Kentucky. Although the conclusions should 

be regarded as prelininary because of the small number of samples, the data in this table suggest that the vein black and yellow 

sphalerites are highest in both gallium and germanium in Zone 

1, where the temperatures at the time of deposition were highest. 

This relation is indicated in table 3 by a comparison of the black 

and yellow sphalerites of Stages 1, 2, and 3 from Zone 1 to Zone 

3.

TABLE 3. Average germanium and gallium content of sphalerites from the 

central Kentucky mineral district showing distribution by zone and stage of 

mineral distribution

[Values are in percent. Numbers in parentheses indicate number of analyses. Analysis by 

semiquantitative spectrograph; U.S. Geol. Survey analyst, J. Harris, 1963, 1964]

Color of sphalerite Element Zone 1 Zone 2 Zone 3

Stage

Stage

Stage

1

2

3

Black

Black

Yellow

do

and

do

and

Ho

yellow

black

Red and orange

do

Ge

Ga

Ge

Ga

Ge

Ga

Ge

Ga

0.04

.01

.03

.009

.03

.006

(8)

(8)

(4)

(4)

(1)

(1)

0.01

.007

.02

.006

0

.005

(1)

(1)

(6)

(6)

(1)

(1)

0.01

.008

.01

.008

.007

.004

.08

.01

(3)

(3)

(9)

(9)

(1)

(1)

(3)

(3)
F20 CONTRIBUTIONS TO ECONOMIC GEOLOGY

The late-stage red-orange sphalerites of both central Kentucky 

and central Tennessee (examples in table 2) contain on the 

average more germanium than other types. Red sphalerite from 

the Cumberland River veins in south-central Kentucky contains 

0.07 to 0.1 percent germanium. Red sphalerite is most abundant 

in some veins of Zone 3, where the temperatures of formation are 

lowest. Although representative samples are not shown for all 

zones in table 3, red sphalerite is present as a late mineral in 

minor amounts in a few veins in every zone of the central Kentucky district, where it occurs as an overgrowth on earlier 

sphalerites, or in crosscutting veinlets with purple fluorite, and 

commonly replaces wallrock.

Several second-stage black and yellow sphalerites from the 

central Kentucky veins were separated by hand into black and 

yellow parts. For each sample, it was found that the yellow part 

was one order higher in both germanium and gallium than the 

black part. At the Purdy vein in Bourbon County, Ky., where 

black sphalerite forms the core to the sample analyzed, it was 

found that the germanium and gallium content increases from the 

black interior through outer rims of first yellow and last reddish 

orange. The cadmium conte,nt remains rather constant in all specimens analyzed. Although the dark-yellow sphalerite that is intergrown with the black is high in these elements, such is not true 

of a late very pale yellow sphalerite of the same district. In contrast to this pattern is a late (Stage 3) pale-yellow sphalerite 

collected in a roadcut vein near Danville, Ky.; it contains no germanium and is moderately lean in gallium, but is rich in cadmium.

Table 2 shows several complete semiquantitative spectrographic 

analyses of representative sphalerite samples from central Kentucky and central Tennessee as well as from several other 

districts. The sphalerite samples in table 2 from central Kentucky are selected sphalerites representing three mineral stages 

that range from Stage 1 in Zone 1 to Stage 3 in Zone 3. There is 

a close similarity between the minor elements of the central Kentucky sphalerites and those of central Tennessee, except for a 

general lack of silver in the sphalerites of central Tennessee. 

Sphalerites from central Kentucky and some from central Tennessee also contain strontium, which is notably lacking in all other 

sphalerites analyzed to date. One specimen each from the Sweetwater district, Tennessee, Dyer Hill, western Kentucky and Flat 

River, Mo., contain strontium and are exceptions in more than 100 

analyses. The diagenetic sphalerites of central Kentucky are also 

lacking in strontium.
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F21

Semiquantitative spectrographic analyses of sphalerites collected from the hydrothermal veins and massive sulfide deposits 

of Maine, New England, and Pennsylvania indicate that the 

presence of gallium and germanium may well be a function of 

temperature as well as availability in a metallogenic province. 

Selected samples are shown in table 2 for comparison. Sphalerite 

from veins along the Triassic border zone at Bristol, Conn., and 

at Phoenixville, Pa., are similar to the Appalachian Valley zinc 

sphalerites in cadmium, germanium, gallium, and iron content. 

The sphalerites from Hancock and Washington Counties, Maine, 

and Carroll County, N.H., either lack or contain very low amounts 

of germanium and gallium. These sphalerites contain 5 to 10 percent iron and are thought to have been deposited at higher temperatures than those from either the Appalachian Valley zinc 

districts or the Bristol, Conn., deposits. Molybdenum, indium, and 

tin are elements found in the northeastern sphalerites that do not 

occur in most Appalachian and Mississippi Valley sphalerites. 

Indium was reported (Herbert and Young, 1956, p. 16, table 3) 

in sphalerites of the Timberville district, Virginia, and is known 

to occur in sphalerites of the southeast Missouri district. Indium 

was also reported by Stoiber (1940) as occurring in a single 

specimen from central Kentucky. In the many .samples analyzed 

since, however, no indium has been detected, and it probably 

does not exist as a significant trace element that is typical of these 

sphalerites. Many of the sphalerites from Hancock a*nd Washington Counties, Maine, have high silver values.

MERCURY IN OTHER ORES

On the basis of a study of mercury halos derived from lead-zinc 

deposits in Carboniferous limestone and dolomites in the Achisai 

district of the U.S.S.R., Fursov (1958) concludes that:

1. Mercury halos at the surface represent epicenters of blind ore 

bodies 25 to 300 meters below the surface.

2. Mercury dispersion halos within boundaries of the Achisai ore 

field should be regarded as an indirect indication of lead-zinc 

ores.

3. Mercury halos exist in areas where halos of lead and zinc are 

entirely absent.

4. Mercury is in sulfide and oxidized ores and in galena, sphalerite, pyrite, cerussite, and smithsonite. In general, cerussite 

from the oxidized zone contains the most mercury. (The mercury apparently accumulated in the cerussite by migration from 

the original adjacent host sphalerite, which was removed by
F22 CONTRIBUTIONS TO ECONOMIC GEOLOGY

leaching. The more mobile element zinc was redeposited further

out in the wallrock as smithsonite.) 

5. Mercury has a very low mobility in unheated ground water, as

does lead, but it is highly mobile as a vapor. 

Ozerova (1959) concludes that mercury dispersion halos have a 

considerable advantage over lead halos because they are more 

extensive, a circumstance important in locating major areas for 

more detailed prospecting.

MERCURY IN OTHER MINERALS

Saukov (1946) and Ozerova (1959) also indicate that Hg+a 

may replace Ca+2 or Ba+2. Barite, calcite, and galena occur 

with sphalerite in many of the eastern and central mineral deposits. A few analyses for mercury were made on scattered: samples of these minerals, as well as on oxidized ore, from Virginia, 

Kentucky, and Tennessee. All samples contain greater than background mercury. Barite from the Gratz vein, Owen County, Ky., 

which was analyzed by wet chemical methods, contains less than 

300 ppb mercury. The amount of mercury detected in five galena 

samples from Kentucky and Virginia is 270 to 720 ppb. Preliminary analyses suggest that galena-bearing limestone from the 

Gordon-Wine prospect in the Timberville district of Virginia and 

from the Osborn mine in Russell County, Va., contains 200 to 700 

ppb mercury.

Smithsonite from the Timberville mine in Rockingham County, 

Va., contains 15,000 ppb mercury, as indicated by a spectrographic analysis (U.S. Geol. Survey analyst, H. Worthing, 1967). 

Samples of oxidized ore, principally smithsonite, from the Hoover 

vein and the nearby Pascal vein of Cannon County, Tenm., contain less than 100 ppb mercury by wet chemical analysis (U.S. 

Geol. Survey analyst, J. Dinnin, 1965).

MERCURY IN WALLROCK

In permeable rock such as sandstone, limestone, or dolomite, 

mercury moves rather great distances from the source as a vapor 

or soluble mercuric chloride (Hawkes and Webb, 1962). It would 

be reasonable to expect, therefore, a broad hypogene halo of mercury dispersion in host rocks of lead and zinc ores. The shape of 

the resulting mercury anomaly depends upon the shape of the 

fractures and physical characteristics of the wallrock.

Mercury anomalies have most commonly been detected by 

analysis of bedrock rather than soil. According to Williston 

(1964), however, even analysis of mercury in air may be utilized 

in the future. Friedrich and Hawkes (1966) have suggested that 

the mercury content of residual soil, but not of the unweathered
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F23

rock, may be used as a guide to blind ore deposits in the PachucaReal del Monte district, Mexico.

Limestone wallrock suites from the main Faircloth vein in 

central Kentucky, the Mascot-Jefferson City belt of east Tennessee, and the Hoover vein in central Tennessee were analyzed 

for mercury by refined vapor absorption methods. The results 

shown in figure 3 and tables 4, 5, and 6 are well above the accuracy 

limit (1 to 2 ppb) of the method used.

A very narrow mercury leakage anomaly is indicated by the 

analyses. At the Faircloth vein, sample 3 was collected from the 

wallrock breccia at the center of the vein (see fig. 3); as might 

be expected, it contains the most (170 ppb) mercury. The specimen with the least amount of mercury (10 ppb) was collected 30 

feet west of the vein. All samples were collected from a single 

limestone bed in the Tyrone Limestone of Middle Ordovician age, 

except the one in the vein center.

At the Hoover vein (table 5), sample 1, collected from the center of the vein, contains the most mercury (560 ppb). All samples 

were collected from a single limestone bed in the Carters LimeTABLE 4. Variance of mercury content in a suite of limestone samples frotn 

the Faircloth vein, Woodford County, Ky.

[Vapor absorption analyses, U.S. Geol. Survey analyst, J. H. McCarthy, 1964]

Specimen

3

5

6

7

8

9

10

11

Location and description Mercury 

(ppb)

170

80

. . 20

20

_ _ 50

10

_ _ 30

70

TABLE 5. Mercury content of limestone wallrock from the Hoover vein, shaft 

1, Cannon County, Tenn.

[Atomic absorption analyses, U.S. Geol. Survey analyst, James Frisken, Dec. 12, 1966]

Specimen Location and description Mercury

(ppb)

1 Center of vein, altered, silicified limestone ____________ 560

2 East wall, altered, silicified limestone _________________ 70

3 1 ft. east of vein, altered, silicified limestone ___________ 70

4 4 ft. east of vein, unaltered limestone _______________ 30

5 84 ft. southeast of vein, unaltered limestone ______- - 40

6 119 ft. southeast of vein, unaltered limestone __________ 40

7 199 ft. southeast of vein, unaltered limestone ____-_-____ 60

8 244 ft. southeast of vein, unaltered limestone _________- 70

9 Soil above smithsonite cap on vein ___________ 2,200
F24 CONTRIBUTIONS TO ECONOMIC GEOLOGY
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F25

TABLE 6. Mercury content of a wallrock suite along a thinned, altered, and 

silicified limestone bed of a major ore body in the Mascot-Jefferson City 

belt, east Tennessee

[Atomic absorption analyses, U.S. Geol. Survey analyst, James Frisken, Dec. 12, 1966]

Specimen Location and description Mercury

(PPb)

1 Founder breccia, near edge of main ore, thinned, altered, and

silicified chert; 3 in. thick ______________________ 170

2 37 ft. west of sample 1, thinned, altered, and silicified chert _ 40

3 41 ft. west of sample 1 next to shear, thinned, altered, and

silicified chert _____________ .________ 10

4 42 ft. west of sample 1, just west of shear, much thinned,

altered, and silicified chert ._ _ 10

5 58 ft. west of sample 1, thinned, altered, and silicified chert _ 40

6 86 ft. west of sample 1, thinned, altered, and silicified chert _ 20

7 140 ft. west of sample 1, thinned, altered, and silicified limy

chert; 6 in. thick _____________________________ 30

8 205 ft. west of sample 1, thinned, altered, and silicified limy

chert; 10 in. thick ____.______________________ 20

9 280 ft. west of sample 1, thinned, slightly altered limestone;

1.5 ft. thick _________________________ 20

stone of Middle Ordovician age, except sample 1, from the center 

of the vein, and sample 9, from the soil above the vein. Sample 4 

contains the least (30 ppb) mercury and is 4 feet east of the vein, 

indicating a very narrow anomaly. Soil directly over the vein contains even higher amounts (2,200 ppb mercury), suggesting that 

analysis of residual soils might provide a more pronounced 

anomaly. Sphalerite from the Hoover contains 300 to 700 ppb 

mercury (table 1).

Sample 1 from the east Tennessee suite (table 6), which also 

contains anomalous mercury (170 ppb), was collected from the 

edge of a main ore body where the siliceous limestone unit of the 

Kingsport Formation, locally known as the 46 chert, has been 

much altered and thinned to a chert bed only 3 inches thick. 

Where it is unaltered, the 46 chert is nearly 3 feet thick and is 

composed of limestone. Samples 3 and 4, which contain the least 

(10 ppb) amount of mercury, are within 1 foot of a shear zone 

along which postore hydrothermal alteration has occurred, as 

suggested by chemical and mineralogical studies now in progress. 

The sharp drop from 40 to 10 ppb at this point in the wallrock 

suite may be the result of removal or leaching of the original 

mercury by these late warm waters. The lowest mercury content 

might otherwise be expected in the least altered samples, 8 and 9, 

which contain 20 ppb.

Low mercury content is characteristic of limestone. The average mercury content of limestone, according to Rankama and 

Sahama (1950), is 33 ppb. Ozerova (1959) reported that the 

average limestone and sandstone of the Fergana Karatu Range,
F26 CONTRIBUTIONS TO ECONOMIC GEOLOGY

U.S.S.R., contains 2x10"" percent (20 ppb) mercury. The average shale contains 400 ppb mercury (Hawkes and Webb, 1962, 

p. 369), and the average igneous rock (Saukov, 1946) contains 

77 ppb.

The limestone in the visibly unaltered wallrock of the Faircloth, 

Hoover, and the east Tennessee deposits (see tables 4, 5, and 6) 

ranges from 10 to 70 ppb mercury, whereas the more sllicified 

samples .nearest the deposits contain 70 to 560 ppb mercury. All 

analyses above 30 ppb, however, should be considered anomalous. 

Accordingly, samples 8, 10, and 11 of the Faircloth and samples 

7 and 8 of the Hoover suites are thought to be near other veins 

as yet undiscovered.

Quartz, as disseminated replacement crystals and jasperoid, 

and dolomite commonly form alteration aureoles near veins in 

these and other lead-zinc districts (Hosterman and others, 1964) 

of the Central United States. At the Faircloth and Hoover veins, 

where silicification is most pronounced in the altered wallrock 

nearest the vein (see fig. 3 and table 5), mercury content is also 

highest. However, silicification does not seem to bear any relationship to the amount of mercury present in the deposit from east 

Tennessee or to the anomalous samples some distance removed 

from the known veins.

CONCLUSIONS

Mercury has been reported as a trace element in sphalerite and 

other minerals from the Western United States and other parts 

of the world, but this is the first notation of such an occurrence 

in the lead-zinc deposits of the Central and Eastern United States. 

Mercury has been detected in amounts greater than background 

in nearly every sphalerite analyzed, indicating that it is a very 

common and widespread trace element in most zinc deposits of 

Central and Eastern United States. The presence of mercury as 

an integral part of sphalerite suggests that these deposits are 

hydrothermal in origin that is, they were deposited by heated 

aqueous solutions, which in the deposition of sphalerite of the 

Mississippi Valley type were probably largely heated connate 

brines. The presence of mercury anomalies associated with the 

central Kentucky, central Tennessee, and east Tennessee deposits 

suggests that other districts containing base metals in the Central 

and Eastern United States also have mercury wallrock halos associated with them. It is hoped that the knowledge of mercury association with these ore bodies will be of help in prospecting for
MERCURY IN SPHALERITE, CENTRAL AND EASTERN STATES F27

other low- to moderate-temperature deposits in the Central and 

Eastern United States, especially in the Mississippi Valley and 

Appalachian Valley zinc districts.

Trace elements such as mercury, cadmium, germanium, and 

gallium should not be overlooked when considering the total value 

of the zinc concentrates. These elements, especially mercury, 

cadmium, and germanium, may occur in sufficient quantities in 

some sphalerites, such as those of the central Kentucky and central Tennessee districts, to warrant consideration as worthwile 

byproducts at the smelters if new commercial ore bodies are found 

and mined. The unusual concentrations of these elements in the 

sphalerite of these two districts is a feature that distinguishes 

the deposits from those in many other districts. The east Tennessee and other Appalachian Valley sphalerites are notably 

leaner in germanium and mercury than those of central Tennessee and central Kentucky. The central Kentucky diagenetic 

sphalerites are very lean in cadmium, germanium, and gallium 

as compared with those in nearby veins. Comparison of central 

Kentucky and northeastern hydrothermal vein and massive sulfide 

sphalerites indicates that the amount of cadmium present is most 

likely a result of abundance in a metallogenic province high in 

cadmium, whereas germanium, gallium, and mercury contents 

may be related to temperature of deposition as well as to source.

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