Carlin-Type Gold Deposits in Nevada: Critical Geologic Characteristics and Viable Models
©2005 Society of Economic Geologists, Inc. Economic Geology 100th Anniversary Volume pp. 451–484 Carlin-Type Gold Deposits in Nevada: Critical Geologic Characteristics and Viable Models JEAN S. CLINE,† University of Nevada, Las Vegas, 4505 Maryland Parkway, Box 454010, Las Vegas, Nevada 89154-4010 ALBERT H. HOFSTRA, Mineral Resources Program, U.S. Geological Survey, Mail Stop 973, Box 25046, Denver, Colorado 80225 JOHN L. MUNTEAN, Nevada Bureau of Mines and Geology, Mail Stop 178, University of Nevada, Reno, Nevada 89557-0088 RICHARD M. TOSDAL, AND KENNETH A. HICKEY Mineral Deposit Research Unit, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia, Canada V6T 1Z4 Abstract Carlin-type Au deposits in Nevada have huge Au endowments that have made the state, and the United States, one of the leading Au producers in the world. Forty years of mining and numerous studies have pro- vided a detailed geologic picture of the deposits, yet a comprehensive and widely accepted genetic model re- mains elusive. The genesis of the deposits has been difficult to determine owing to difficulties in identifying and analyzing the fine-grained, volumetrically minor, and common ore and gangue minerals, and because of postore weathering and oxidation. In addition, other approximately contemporaneous precious metal deposits have overprinted, or are overprinted by, Carlin-type mineralization. Recent geochronological studies have led to a consensus that the Nevada deposits formed ~42 to 36 m.y. ago, and the deposits can now be evaluated in the context of their tectonic setting. Continental rifting and deposi- tion of a passive margin sequence followed by compressional orogenies established a premineral architecture of steeply dipping fluid conduits, shallow, low dipping “traps” and reactive calcareous host rocks.
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