Bulletin . ly in asingle piece of ore from the dmnp of the High Hill mine. In this specimenthe silver occurred as a thin film in a minute fracture in the ore, and wasclearly of supergene origin. RELATION OF THE COPPER-BEARING SULPHIDES TO EACH OTHER. General statement.—The relations of the sulphides to each other havebeen discussed with some thoroughness in the pages devoted to the detaileddescription of the ores, pp. 63-82, but it has been thought best to repeatand to some extent enlarge, in this place, the descriptions of the inter-relations of the ore minerals which have a bearing upon thei
Bulletin . ly in asingle piece of ore from the dmnp of the High Hill mine. In this specimenthe silver occurred as a thin film in a minute fracture in the ore, and wasclearly of supergene origin. RELATION OF THE COPPER-BEARING SULPHIDES TO EACH OTHER. General statement.—The relations of the sulphides to each other havebeen discussed with some thoroughness in the pages devoted to the detaileddescription of the ores, pp. 63-82, but it has been thought best to repeatand to some extent enlarge, in this place, the descriptions of the inter-relations of the ore minerals which have a bearing upon their origin,deposition, and the secondary alterations which they have suffered. Ofgreatest importance in these respects are the graphic intergrowths betweenbornite and chalcocite in the primary ores, or, in other words, the oresbelieved to be of hypogene origin. These relationships are so character-istically different from those of the secondary, or supergene sulphides, VIRGINIA GEOLOGICAL SURVEY. PLATE rnm (B) Photomicrograph of a polished section of ore from the Pontiac mine (Glasscockshaft). Shows typical supergene chalcocite in bornite. Similar in allrespects to the section shown in (Ai. White = chalcocite. Gray = bornite. Black = pits. VIRGINIA GEOLOGICAL SURVEY. PLATE XII.
Size: 1574px × 1587px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectgeology, booksubjectm
