Overview:
Carlin-type deposits are sediment hosted, disseminated gold deposits thought to be associated with hydrothermal activity. They are named for the first discovery of this deposit style near Carlin, located in northeastern Nevada, USA. Carlin-type deposits are characterized by micro-gold particles in pyrite and arsenopyrite. Carlin-type Au deposits appear unique to the western U.S. with occurrences along several trends, primarily in Nevada. Other similar type deposits are known in Iran, Yukon, and China but experts often disagree on whether these non-Nevada deposits are truly Carlin-type Au deposits.
Chemistry of Carlin-type Au show enrichments of Au, As, Sb, Hg, Th, Ba, with limited Ag enrichment in some deposits. These deposits typically show an absence of base metals. Lithologically, these deposits are commonly hosted in silty carbonates and more rarely in carbonaceous sandstones. Mineral enrichment is hypothesized to be associated with hydrothermal circulation with temperatures up to 300 degrees C. A key exploration feature with close association is the presence of jasperoid. This is due to silica-enrichment during hydrothermal alteration of dolomites into a common red, weathering resistant zone of jasperoid.
Carlin References (free):
Carlin-type references:
Kesler, S.E., Riciputi, L.C., and Ye, Z. (2005) Evidence for a Magmatic Origin for Carlin-Type Gold Deposits: isotopic composition of sulfur in the Betze-Post-Screamer Deposit, Nevada, USA.
Radtke, A., (1985) Geology of the Carlin Gold Deposit, Nevada. U.S. Geological Survey Professional Paper 1267.