Bootstrap window, Elko and Eureka Counties, Nevada

Journal of Research of the U.S. Geological Survey
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Abstract

The Bootstrap window in the Roberts Mountains thrust of north-central Nevada contains a 1,500-ft (460-m)- thick autochthonous section of carbonate assemblage rocks. These carbonate rocks include the upper part of the Roberts Mountains Formation and an unnamed limestone of Devonian age. They contain abundant material that must have been deposited in or near a reef. Allochthonous chert and shale of the siliceous assemblage, presumably Ordovician and Silurian in age, are present around the window and in a north-trending graben within the window.

The Paleozoic rocks contain altered dikes, most of which may originally have been granodioritic. The localized recrystallization in the Paleozoic rocks probably occurred during dike emplacement. Sometime after the intrusion; both the dikes and their host rocks were epithermally altered. Some gold has been mined, and relatively high gold values (≥1 ppm) occur in rocks of the siliceous assemblage in and near the northern part of the steep north-trending fault zone on the west side of the graben. Areas of secondary alteration and of high values of silver and mercury are more widespread than the area of high gold values. The highest concentrations of silver and mercury, however, are also found near the same gold-bearing fault zone.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Bootstrap window, Elko and Eureka Counties, Nevada
Series title Journal of Research of the U.S. Geological Survey
Volume 4
Issue 1
Year Published 1976
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Description 7 p.
First page 119
Last page 125
Country United States
State Nevada
County Elko Coundy, Eureka County
Other Geospatial Roberts Mountains
Online Only (Y/N) N
Additional Online Files (Y/N) N