Upward secondary sulphide enrichment and chalcocite formation at Butte, Montana

Austin Flint Rogers
1913 Economic Geology and The Bulletin of the Society of Economic Geologists  
Though first hinted at by Gonzalo y Tarin 2 in 'his monograph on Huelva, in •888, and by Fu.chs and de Launay, a in •893, the development of the idea of secondary sulphide enrichment is the result almost entirely of the observations of American geologists and constitutes perhaps the most important American contribution to the theory of ore-deposits. The pioneer papers of S. F. Emmons, 4 Weed, * and Van Hise ø appeared almost simultaneously in' the same year (•9oo). Ransome's 7 valuable paper on
more » ... 7 valuable paper on "Criteria of Downward Sulph,ide Enrichment" was followed by interesting discussions by Foote, Gregory, Keyes, Louis, Sales, Wells, and A. N. Winchell in volume five of EcoNoMic G•oLoG¾. An excellent short summary of secondary sulphide enrichment (with bibliography) by Tolman s appeared early in •9•3, and recently a comprehensive summary of the whole subject by W. H. Emmons ø has been published by the United States Geological Survey. ß The objection to the use of the term has been pointed out to the writer by Prof. C. F. Tolman and Prof. W. H. Emmons. Prof. Emmons suggests deep-seated metasomatic development of chalcocite, but for the sake of argument the term as given is retained. • Reference cited by Becker in Emmons' volume on Ore Deposits, p.' xxxix. " Trait• des Gites Min•raux et
doi:10.2113/gsecongeo.8.8.781 fatcat:tiukg6rk2fepjimc5eu3jinmj4