New Open-File Report—in Elko County

Subsurface Trenching Investigation in Support of the Barrick Goldstrike N. Carlin Trend Structure Project
by Richard D. Koehler and Colin M. Chupik
Year: 2018
Series: Open-File Report 18-2
Format: text: 18 pages, color; 12 plates: 11 x 17 inches, color
Scale: 1:60
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Surface geomorphic analyses and subsurface geologic trenching was conducted by the Nevada Bureau of Mines and Geology at a site in the Tuscarora Mountains in Elko County, Nevada within the northern Carlin Trend. The purpose of the investigation was to assess the presence or absence of active faults, refine previous bedrock mapping, and document the locations of stratigraphic contacts and the character of faults and other discontinuities. Surficial evidence of Quaternary faulting was not observed in the project area; however, the Southeast Sheep Creek Range fault and the Tuscarora fault zone project towards the site. Two east-west oriented trenches were excavated for a total exposure of ~3,000 feet (~915 meters). Bedrock exposed in the trenches included the Devonian Slaven Formation and the Tertiary Carlin Formation. Numerous small displacement faults, joints, and other discontinuities associated with carbonate seams and secondary mineralization were documented. A well-developed textural B soil horizon is developed across the entire exposure indicating that tectonic deformation predates the late Pleistocene. Together, the results provide information applicable to refining bedrock maps and improving regional and local structural models.