Reconnaissance survey of the Roberts Mountains, Nevada

Geological Society of America Bulletin
By:  and 

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Abstract

The Roberts Mountains region, central Nevada, provides an excellent section of Paleozoic rocks ranging from Upper Cambrian to Permian. Major low-angle thrusting is indicated by deformed Ordovician strata resting on Paleozoics of varying age. Overlying a thick breccia zone, the upper thrust plate consists of sandstones, andesitic flows and tuffs, black shales, and bedded cherts (Vinini formation). Ordovician age of the Vinini is established on the basis of graptolite faunules. A belt of Lower to Middle Ordovician graptolitic facies similar to the Vinini formation crosses the Great Basin west of Roberts Mountains. Deposits of roughly the same age in the Roberts Mountains meridian and eastward are dominantly limestone, carrying distinct faunas. Axial planes of overturned folds in the thrust plate dip west, a further indication that the upper thrust plate moved from west to east. Minimum horizontal displacement is 16 miles. The date of thrusting is uncertain, but presumably was later Cretaceous or early Tertiary. Following thrusting, an alaskite stock and rhyolite porphyry plugs were intruded; lava flows and tuffs covered the area in part. Thrust plate and cover of volcanics have been broken into normal fault blocks. The post-thrusting igneous rocks, like volcanic rocks of Utah and New Mexico, are characterized by high potash content. © 1492 Geological Society of America.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Reconnaissance survey of the Roberts Mountains, Nevada
Series title Geological Society of America Bulletin
DOI 10.1130/GSAB-53-1675
Edition 1
Volume 53
Issue 12
Year Published 1942
Language English
Publisher Geological Society of America
Description 53 p.
First page 1675
Last page 1727
Country United States
State Nevada
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