Abstract
Two styles of gold dendrites are variably developed at the McLaughlin Mine. The most abundant occurrence is hosted by amber-coloured hydrocarbon-rich opal. Silica likely precipitated from a boiling hydrothermal fluid and complexed with immiscible hydrocarbons forming an amorphous hydrocarbon-silica phase. This phase likely scavenged particulate gold by electrostatic attraction to the hydrocarbon-silica phase. The dendritic nature of the gold is secondary and is the result of dewatering of the amorphous hydrocarbon-silica phase and crystallization of gold into syneresis fractures. The second style of dendritic gold is hosted within vein swarms that focused large volumes of fluid flow. The dendrites occur along with hydrocarbon-rich silica at the upper contact of the vein margins which isolated the dendrites allowing sufficient time for them to grow. In a manner similar to the amber-coloured opal, the dendrites may have formed by scavenging particulate gold by electrostatic attraction to the hydrocarbon-silica phase.
Similar content being viewed by others
References
Bailey, E.H. (1959) Froth veins, formed by immiscible hydrothermal fluids, in mercury deposits, California. Geol. Soc. Am. Bull. 70:661–664
Bennett, P., Siegel, D.I. (1987) Increased solubility of quartz in water due to complexing by organic compounds. Nature 326:684–686
Bennett, P.C., Melcer, M.E., Siegel, D.I., Hassett, J.P. (1988) The dissolution of quartz in dilute aqueous solutions of organic acids at 25 °C. Geochim. Cosmochim. Acta 52:1521–1530
Blake, M.C. Jr., Jones, D.L. (1981) The Franciscan assemblage and related rocks in northern California: a reinterpretation. In: Ernst, W.G. (ed.) The geotectonic development of California, Rubey Volume I. Prentice-Hall, Englewood Cliffs, New Jersey, pp. 306–328
Dickinson, W.R. (1981) Plate tectonics and the continental margin of California. In: Ernst, W.G. (ed.) The geotectonics development of California, Rubey Volume I. Prentice-Hall, Englewood Cliffs, New Jersey, pp. 1–29
Disnar, J.R., Sureau, J.F. (1990) Organic matter in ore genesis: progress and perspectives. Org. Geochem. 16:577–599
Fournier, R.O. (1985) The behavior of silica in hydrothermal solutions in epithermal systems. In: Berger, B.R., Bethke, P.M. (eds.) Geology and geochemistry of epithermal systems. Rev. Econ. Geol. 2:45–61
Frondel, C. (1938) Stability of colloidal gold under hydrothermal conditions. Econ. Geol. 33:1–20
Gatellier, J.P., Disnar, J.R. (1990) Kinetics and mechanism of the reduction of Au(III) to Au(0) by sedimentary organic materials. Org. Geochem. 16:631–640
Gustafson, D.L. (1991) Anatomy of a discovery: the McLaughlin gold mine, Napa, Yolo, and Lake counties, California. In: Hutchinson, R.W., Grauch, R.I. (eds.) Historical perspectives of genetic concepts and case histories of famous discoveries. Econ. Geol. Monogr. 8:350–359
Haas, J.L. (1971) The Effect of salinity on the maximum thermal gradient of a hydrothermal system at hydrostatic pressure. Econ. Geol. 66:940–946
Hearn, B.C. Jr., Donnelly-Nolan, J.M., Goff, F.E. (1981) The ClearLake volcanics: tectonic setting and magma sources. In: McLaughlin, R.J., Donnelly-Nolan, J.M. (eds.) Research in the Geysers-Clear Lake geothermal area, northern California, U.S. Geol. Sur. Pro. Paper 1141:25–46
Herrington, R.J., Wilkinson, J.J. (1993) Colloidal gold and silica in mesothermal vein systems. Geology 21: 539–542
Jowett, E.C. (1992) Role of organics and methane in stratiform Cu-Ag deposits and evidence of quartz dissolution by organic complexes. In: GAC-MAC, Joint Annual Meeting, Program with Abstracts
Lehrman, N.J. (1986) The McLaughlin Mine, Napa and Yolo counties, California. In: Tingley, J.V., Bonham, H.F. Jr. (eds.) Precious-metal mineralization in hot-springs systems, Nevada-California, Nev. Bureau Mines Geol. Report 41:85–89
Lehrman, N.J. (1990) The McLaughlin Mine, California: an update. GAC-MAC Joint Annual Meeting, Program with Abstracts
Peabody, C.E., Einaudi, M.T. (1992) Origin of petroleum and mercury in the Culver-Baer cinnabar deposit, Mayacmas district, California. Econ. Geol. 87:1078–1103
Pearcy, E.C. (1989) The geology and evolution of the hot spring gold deposit at Cherry Hill, California. Unpublished Ph.D. thesis, Harvard University, 248 pp
Pearcy, E.C., Peterson, U. (1990) Mineralogy, geochemistry and hydrothermal alteration of the Cherry Hill hot-spring gold deposit. In: Hedenquist, J.W., White, N.C., Siddeley, G. (eds.) Epithermal gold mineralization of the circum-Pacific. Ass. Expl. Geochem. Spec. Publ. 16b: 143–170
Peters, E.K. (1991) Gold-bearing hot spring systems of the northern Coast Ranges, California. Econ. Geol. 86:1519–1528
Rytuba, J.J. (1993) Epithermal precious-metal and mercury deposits in the Sonoma and Clear Lake volcanic fields, California. In: Rytuba, J.J. (ed.) Active geothermal systems and gold/mercury deposits in the Sonoma/Clear Lake Volcanic Fields, California. Soc. Econ. Geol. Guidebook Series 16:38–51
Saunders, J.A. (1990) Colloidal transport of gold and silica in epithermal precious-metal systems: evidence from the Sleeper Deposit, Nevada. Geology 18:757–760
Saunders, J.A. (1994) Silica and gold textures in bonanza ores from the Sleeper deposit, Humbolt county, Nevada: evidence for colloids and implications for epithermal ore-forming processes. Econ. Geol. 89:628–638
Saunders, J.A., Schoenly, P.A. (1993) Boiling-induced chaos and the genesis of gold dendrites in bonanza epithermal Au-Ag deposits. Geol. Soc. Am. Ann. Meeting, Program with Abstracts
Sherlock, R.L. (1992) The empirical relationship between gold-mercury mineralization and hydrocarbons, in the northern Coast Ranges, California. GAC-MAC Joint Annual Meeting, Program with Abstracts
Sherlock, R.L. (1993a) The geology and geochemistry of the McLaughlin Mine sheeted vein complex, northern Coast ranges, California. Unpublished Ph.D. Thesis, University of Waterloo, 309 pp
Sherlock, R.L. (1993b) The genesis of the McLaughlin Mine sheeted vein complex, fluid inclusion and stable isotope evidence. In: Rytuba, J.J. (ed.) Active geothermal systems and gold/mercury deposits in the Sonoma/Clear Lake Volcanic Fields, California. Soc. Econ. Geol. Guidebook Series 16:330–349
Tosdal, R.M., Enderlin, D.A., Nelson, G.C., Lehrman, N.J. (1993) Overview of the McLaughlin precious metal deposit, Napa and Yolo counties, northern California. In: Rytuba, J.J. (ed.) Active geothermal systems and gold/mercury deposits in the Sonoma/Clear Lake Volcanic Fields, California. Soc. Econ. Geol. Guidebook Series 16:312–329
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Sherlock, R.L., Lehrman, N.J. Occurrences of dendritic gold at the McLaughlin Mine hot-spring gold deposit. Mineral. Deposita 30, 323–327 (1995). https://doi.org/10.1007/BF00196368
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00196368