![]() ![]() The pyrite-realgar ores were deposited by heated retention waters driven through a conjugate fault system by heat generated from volcano-magmatic activity. ![]() The early minerals (pyrite, pyrrhotite, arsenopyrite) found in all three ore types, crystallized at temperatures between 380° and 300☌ the late minerals (realgar, orpiment, stibnite, fahlerz, and sulfosalts of Pb, Tl, Hg, Cu, etc.) formed between 250° and 100☌. Mineralization is believed to have formed at a depth of 1 to 1.5 km and at pressures of 0.15 to 0.6 kbar. Native gold particles are characteristically small (< 10 μm) and their fineness is 910 to 995 in the pyrite-realgar ores, 735 to 950 in the sulfosalt-base metal ores and < 700 in the base metal ores. Types 2 and 3 are hosted by jasperoids and form the outer zone of the deposit which is enriched in As, Sb, Ag, Zn, Cu, and Pb with Au/Ag ratios < 1.0. If you want to continue learning this skill and join our regular Practice sessions, we would welcome you to become a member « All Events. #Oolite stone wall how toThree different ore-types have been recognized: (1) Carlin-like pyrite-realgar ores with a Au/Ag ratio >1.0, accompanied by quartz-sericitic metasomatites, form an inner zone (2) sulfosalt-base metal ores and (3) base metal ores. If you would like to understand how to build a dry stone wall, why not join one of our Courses for 2021. ![]() Mineralization occurs within eruptive breccia (limestone fragments cemented by tuffaceous andesitic material) developed at the limestone-tuffaceous rock contact. The ore zone is controlled by a N-S fault which defines the western margin of a granodiorite - quartz diorite. The similarities with Carlin include wallrock alteration, the presence of dusty pyrite, a Au-As-Sb-Hg-Ba association, and Au dominance over Ag. The Vorontsovskoe gold deposit near Serov, about 300 km north of Sverdlovsk in the Urals, has been recognized as being of the Carlin type. ![]()
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