|
1 Nevada Bureau of Mines and Geology, Mail Stop 178, University of Nevada, Reno, NV 89557-0088, USA (e-mail: munteanj{at}unr.edu)
2 Ries-Coward Associates Ltd, 70 Grosvenor Road, Caversham, Reading RG4 5ES, UK
3 Oro Gold Resources Ltd, Suite 1440-625 Howe Street, Vancouver, British Columbia, Canada V6C 2T6
Mappable surface structures control linear trends of Carlin-type gold deposits in north-central Nevada. Some of these structures probably resulted from reactivation of Palaeozoic normal faults, linked to underlying basement faults that originated during rifting of western North America during the Proterozoic. These old faults served as conduits for deep crustal hydrothermal fluids responsible for formation of Carlin-type gold deposits in the Eocene. The reactivated structures are recognized by stratigraphic and structural features. Stratigraphic features include rapid facies changes, growth fault sequences and sedimentary debris-flow breccias. Structural features resulted from inversion of the normal faults during the Late Palaeozoic Antler and subsequent orogenies. Inversion features include asymmetric hanging-wall anticlines, flower-like structures, and floating island geometries. Inversion resulted in structural culminations that occur directly over the basement faults, providing an optimal setting for the formation of Carlin-type gold deposits.