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Retrograde Ag-enrichment in fahlores from the Coeur d'Alene mining district, Idaho, USA

Published online by Cambridge University Press:  05 July 2018

R. O. Sack ,
S. M. Kuehner  and
L. S. Hardy
R. O. Sack*
Affiliation:
Department of Earth & Space Sciences, Box 351310 University of Washington, Seattle, WA, 98195–1310, USA
S. M. Kuehner
Affiliation:
Department of Earth & Space Sciences, Box 351310 University of Washington, Seattle, WA, 98195–1310, USA
L. S. Hardy
Affiliation:
Sunshine Precious Metals Inc., Kellogg, ID 83837, USA
*
*E-mail: sack@geology.washington.edu
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Abstract

Tetrahedrite fahlores from the Coeur d'Alene mining district (Idaho) have been found to be enriched in Ag by the Ag–Cu exchange reaction

which occurred during cooling following galena mineralization. This solid–state reaction resulted in quantitative removal of Ag (in a AgSbS2 component) from galena and development of bournonite coronas on fahlore grains. The reaction produced a distinct population of high-Ag fahlores found in galena-rich samples and accounts for all of the bournonite mineralization. The most argentian of these high-Ag fahlores examined in this study (molar Ag/(Ag+Cu) = 0.303±0.011 and 0.336±0.011) are found in samples which achieved saturation with respect to other Ag-sulfosalts, namely pyrargyrite and polybasite and diaphorite, respectively. Multiple lines of evidence for the Ag-Cu exchange reaction are presented in this paper which applies mass-balance constraints and a thermodynamic database for sulfides/sulfosalts to microprobe analyses and textural observations, and to bulk production data. This solid-state reaction may explain why previous district studies have been unable to demonstrate convincingly primary fahlore zoning. Based on the Ag/(Ag+Cu) of fahlores coexisting with other Agsulfosalts and Fe-Zn partitioning between fahlore and sphalerite, we estimate that fahlore compositions were frozen in by 175°C. Examining the composition data for other Ag tetrahedrite fahlores found in the Coeur d'Alene district and elsewhere, we conclude that the thermodynamic database provides an accurate description of phase equilibria, except possibly for very Fe-rich systems where further studies of the Fe-Zn partitioning between fahlore and Fe-rich (Zn,Fe)S phases and of the thermodynamics of Fe-rich (Zn,Fe)S phases are warranted.

Keywords

tetrahedrite-fahloregalenaCoeur d'Alene mining DistrictIdahoUSAbournonite
Type
Research Article
Information
Mineralogical Magazine , Volume 66 , Issue 1 , February 2002 , pp. 215 - 229
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2002

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References

Amcoff, O. (1976) The solubility of silver and antimony in galena. Neues Jahrbuch für Mineralogie Monatshefte, 1976(6), 247–261.Google Scholar
Anderson, R.J. (1940) Microscopic features of ore from the Sunshine Mine. Economic Geology, 35, 659–667.CrossRefGoogle Scholar
Armstrong, J.T. (1988) Bence Albee after 20 years: review of the accuracy of the a-factor correction procedures for oxide and silicate minerals. Pp. 469–476 in: Microbeam Analysis. (Newbury, D.E., editor). San Fransisco Press, San Fransisco, CA, USA.Google Scholar
Balabin, A.L and Sack, R.O. (2000) Thermodynamics of (Zn, Fe)S sphalerite: a CVM approach with large basis clusters. Mineralogical Magazine, 64, 923–943.CrossRefGoogle Scholar
Charlat, M. and Levy, C. (1974) Substitutions multiples dans la série tennantite-tetrahedrite. Bulletin Societé français Minéralogie et Cristallographie, 97, 241–250.CrossRefGoogle Scholar
Craig, J.R. and Barton, P.B. Jr., (1973) Thermochemical approximations for sulfosalts. Economic Geology, 68, 493–506.CrossRefGoogle Scholar
Cronstedt, A. (1758) Mineralogie; eller Mineral–Rickets Upstallning. Magellan, Stockholm.Google Scholar
Ebel, D.S. (1993) Thermochemistry of fahlore (tetra-hedrite) and biotite mineral solutions. PhD thesis, Purdue University, IN, USA.Google Scholar
Ebel, D.S. and Sack, R.O. (1989) Ag–Cu and As–Sb exchange energies in tetrahedrite-tennantite fahlores. Geochimica et Cosmochimica Acta, 53, 2301–2309.CrossRefGoogle Scholar
Ebel, D.S. and Sack, RO. (1991) As-Ag incompatibility in fahlore. Mineralogical Magazine, 55, 521–528. CrossRefGoogle Scholar
Ebel, D.S. and Sack, R.O. (1994) Experimental determination of the free energy of formation of freibergite fahlore. Geochimica et Cosmochimica Acta, 58, 1237–1242.CrossRefGoogle Scholar
Foord, E.E., Shawe, D.R. and Concklin, N.N. (1988) Coexisting galena, PbS and sulfosalts: Evidence for multiple episodes of mineralization in the Round Mountain and Manhattan gold districts, Nevada. Canadian Mineralogist, 26, 355–376.Google Scholar
Fryklund, V.C. Jr., (1964) Ore deposits of the Coeur d'Alene district, Shoshone County, Idaho. U.S. Geological Survey Professional Paper, 445, 103pp.Google Scholar
Ghosal, S. and Sack, R.O. (1995) As-Sb energetics in argentian sulfosalts. Geochimica et Cosmochimica Acta, 59, 3573–3579.CrossRefGoogle Scholar
Ghosal, S. and Sack, R.O. (1999) Bi-Sb energetics in sulfosalts and sulfides. Mineralogical Magazine, 63, 723–733.CrossRefGoogle Scholar
Goodell, P.C. and Petersen, U. (1974) Julcani mining district, Peru: a study of metal ratios. Economic Geology, 69, 347–361.CrossRefGoogle Scholar
Hackbarth, C.J. (1984) Depositional modeling of tetrahedrite in the Coeur d'Alene district. PhD thesis, Harvard University, Cambridge, MA, USA.Google Scholar
Hackbarth, C.J. and Petersen, U. (1984) Systematic compositional variations in argentian tetrahedrite. Economic Geology, 79, 448–460.CrossRefGoogle Scholar
Hall, W.E. and Czamanske, G.K. (1972) Mineralogy and trace-element content of the Wood River lead-silver deposit, Blaine County, Idaho. Economic Geology, 67, 350–361.CrossRefGoogle Scholar
Harlov, D.E. and Sack, R.O. (1994) Thermochemistry of polybasite-pearceite solutions. Geochimica et Cosmochimica Acta, 58, 4363–4375.CrossRefGoogle Scholar
Harris, R.H., Lange, I.M. and Krouse, H.R. (1981) Major element and isotopic variation in the lower Chester vein, Sunshine mine, Idaho. Economic Geology, 76, 706–715.CrossRefGoogle Scholar
Hoda, S.N. and Chang, L.L.Y. (1975) Phase relations in the system PbS–Ag2S-Sb2S3 and PbS-Ag2S-Bi2S3 . American Mineralogist, 60, 621–633.Google Scholar
Jeanloz, R. and Johnson, M.L. (1984) A note on the bonding, optical spectrum and composition of tetrahedrite. Physics and Chemistry of Minerals, 11, 52–54.CrossRefGoogle Scholar
Johnson, M.L. and Jeanloz, R. (1983) A brillouin-zone model for compositional variation in tetrahedrite. American Mineralogist, 68, 220–226.Google Scholar
Knowles, C.R. (1983) A microprobe study of silver ore in northern Idaho. Pp. 1–64 in: Microbeam Analysis (Gooley, R., editor). San Fransisco Press, San Fransisco, CA, USA.Google Scholar
Klein, C. and Hurlbut, C.S. Jr., (1993) Manual of Mineralogy. John Wiley & Sons, New York.Google Scholar
Lueth, V.W., Megaw, P.K.M., Pingatore, N.E. and Goodell, P.C. (2000) Systematic variation in galena solid solution at Santa Eulalia, Chihuahua, Mexico. Economic Geology, 95, 1673–1687.Google Scholar
Luce, F.D., Tuttle, C.L. and Skinner, B.J. (1977) Study of sulfosalts of copper. V. Phases and phase relations in the system Cu-Sb-As-S between 350°C and 500°C. Economic Geology, 72, 271–289.CrossRefGoogle Scholar
Mitcham, T.W. (1952) Indicator minerals, Coeur d'Alene silver belt. Economic Geology, 47, 414–450.CrossRefGoogle Scholar
O'Leary, M.J. and Sack, R.O. (1987) Fe-Zn exchange reaction between tetrahedrite and sphalerite in natural environments. Contributions to Mineralogy and Petrology, 96, 415–425.CrossRefGoogle Scholar
Pattrick, R.A.D. (1978) Microprobe analyses of cadmium-rich tetrahedrites from Tyndrum, Perthshire, Scotland. Mineralogical Magazine, 42, 286–288.CrossRefGoogle Scholar
Ramdohr, P. (1969) The Ore Minerals and Their Intergrowths, pp. 554–562. Pergamon Press, New York, USA.Google Scholar
Rasor, C.A. (1934) Silver mineralization in the Sunshine mine, Coeur dAlene district, Idaho. MS thesis, University of Idaho, Moscow, ID, USA Google Scholar
Riley, J.F. (1974) The tetrahedrite-freibergite series with reference to the Mount Isa Pb-Zn-Ag orebody. Mineralium Deposita, 9, 117–124 CrossRefGoogle Scholar
Roberts, W.L., Campbell, T.L. and Rapp, G.R Jr., (1990) Encylcopedia of Minerals. (2nd edition) Van Nostrand Reinhold Company, New York, USA.CrossRefGoogle Scholar
Sack, R.O. (1980) Adirondack mafic granulites and a model lower crust. Bulletin of the Geological Society of America, 91, Part I, 89-93, Part II, 349–442.CrossRefGoogle Scholar
Sack, R.O. (1992) Thermochemistry of tetrahedrite-tennantite fahlores. Pp. 243–266 in: The Stability of Minerals. (Ross, N.L. and Price, G.D., editors). Chapman & Hall, London.Google Scholar
Sack, R.O. (2000) Internally consistent database for sulfides and sulfosalts in the system Ag2S-Cu2S-ZnS-Sb2S3-As2S3 . Geochimica et Cosmochimica Acta, 64, 3803–3812.CrossRefGoogle Scholar
Sack, R.O. and Ebel, D.S. (1993) As-Sb exchange energies in tetrahedrite-tennant ite fahlores and bournonite-seligmannite solid solutions. Mineralogical Magazine, 57, 633–640.CrossRefGoogle Scholar
Sack, R.O. and Loucks, R.R. (1985) Thermodynamic properties of tetrahedrite-tennantites: Constraints on the interdependence of the Ag↔Cu, Fe↔Zn, Cu↔Fe, and As↔Sb exchange reactions. American Mineralogist, 70, 1270–1289.Google Scholar
Sack, R.O., Ebel, D.S. and O'Leary, M.J. (1987) Tennahedrite thermochemistry and metal zoning. Pp. 701–731 in: Chemical Transport in Metasomatic Processe. (Helgeson, H.C., editor). D. Reidel, Dordrecht, The Netherlands.CrossRefGoogle Scholar
Sandecki, J. and Amcoff, O. (1981) On the occurrence of silver-rich tetrahedrite from Garpenburg Norra, central Sweden. Neues Jahrbuch für Mineralogie, Abhandlungen, 141, 324–340.Google Scholar
Spiridonov, E.M. (1984) Species and varieties of fahlore (tetrahedrite-tennantite) minerals and their rational nomenclature. Doklady Akademii Nauk, SSSR, 279, 166–172.Google Scholar
Springer, G. (1969) Electron probe analyses of tetrahedrite. Neues Jahrbuch für Mineralogie, Monatshefte, 24–32.Google Scholar
Wavra, C.S., Bond, W.D. and Reid, R.R. (1994) Evidence from the Sunshine Mine for dip-slip movement during Coeur D'Alene district mineralization. Economic Geology, 89, 515–527.CrossRefGoogle Scholar
White, B.G. (1989) Superposed map-scale folds and subsequent veins unrelated to Osburn strike-slip fault, Coeur d'Alene mining district, Shoshone County, Idaho. Geological Society of America. Abstracts with Programs (Rocky Mountain Cordilleran Section), 21, 158.Google Scholar
White, B.G. (1998) New tricks for an old elephant: Revising concepts of Coeur d'Alene geology. Mining Engineering, August, 27–35.Google Scholar
Whitney, P.R. and McLelland, J.M. (1973) Origin of coronas in the Adirondack Mountains, New York. Contributions to Mineralogy and Petrology, 29, 81–98.CrossRefGoogle Scholar
Willard, M.E. (1941) Mineralization at the Polaris mine. Economic Geology, 36, 539–550.CrossRefGoogle Scholar
Wu, I. and Petersen, U. (1977) Geochemistry of tetrahedrite-tennantite at Casapalca, Peru. Economic Geology, 72, 993–1016.CrossRefGoogle Scholar
Zeng, N., Izawa, E., Motomura, Y. and Lai, L. (2000) Silver minerals and paragenesis in the Kangjiawan Pb-Zn-Ag-Au deposit of the Shuikoushan mineral district, Hunan Province, China. Canadian Mineralogist, 26, 11–22.CrossRefGoogle Scholar