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Abstract: Yankee Mine Oil Seep: New Research Yields Additional Evidence of Thrusting; Original Oil Volume in the Seep was Possibly Two Orders of Magnitude Greater Than Previously Calculated

Michael L. Pinnell, Donald W. Anderson

Mesozoic thrusting combined with subsequent Eocene hydrothermal activity have created a regime favorable to major accumulations of both oil and gold in the Long Valley - Buck Mountain - Maverick Springs Range area of northeastern Nevada. Discoveries from ongoing exploration include: Numerous economic accumulations of hydrocarbon associated gold; various thrust relationships from surface geologic mapping and drill holes identifying Devonian rocks faulted onto Permian, Pennsylvanian (?) and Mississippian age rocks; numerous small scale compressional folds and faults indicative of both east vergent (expected) and west vergent (unexpected) structural elements.

Seismic data indicates that oil source rocks, primarily Chainman Shale and Pilot Shale formations, are present to the west in a downdip, subthrust position where hydrocarbon generation and migration would provide large oil volumes to migrate easterly (updip) prior to the formation of the Basin and Range. The Eocene age hydrothermal cell which emplaced gold and oil bearing fluids into the Yankee and associated gold mines probably initiated directly below or east of the Yankee area, but certainly not west of it since no hydrothermal mineralization is present in the Yankee Mine 27-23X Well drilled by Pioneer Oil and Gas west of the mines.

AAPG Search and Discovery Article #90959©1995 AAPG Rocky Mountain Section Meeting, Reno, Nevada