Oligocene or younger thrust faulting in the Ruby Mountains, northeastern Nevada

Ronald Willden; Thomas A. Hermann; T.W. Stern

doi:10.1130/0016-7606(1967)78[1345:ooytfi]2.0.co;2

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Oligocene or younger thrust faulting in the Ruby Mountains, northeastern Nevada

Ronald Willden·Thomas A. Hermann·T.W. Stern

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Abstract

A klippe of unmetamorphosed Devonian carbonate rocks rests on the Harrison Pass intrusive body south of Toyn Creek in the central Ruby Mountains , Elko County, Nevada . This klippe and other klippen of Carboniferous strata - first mapped by R. P. Sharp (1942) - that rest on lower Paleozoic strata are believed to represent a once-continuous thrust sheet that developed after emplacement of the intrusive body. This intrusion of coarse-grained granodiorite to quartz monzonite is exposed over an area of about 45 square miles. Potassium-argon and lead-alpha age determinations on four samples of the intrusive body establish Oligocene or younger age for the thrusting. Potassium-argon age determinations on biotites from the four samples range from 29 to 36 m.y. with a possible analytical error of ±10 percent. Lead-alpha age determinations (all with a possible analytical error of ±10 m.y.) on zircon showed 40 m.y. for three of the samples and 30 m.y. for the fourth. Lead-alpha and potassium-argon dates on a fifth sample collected by R. R. Coats also fall within these ranges. The agreement of the radiometric dates indicates a lack of thermal activity subsequent to the emplacement of the intrusion and establishes a maximum age of Oligocene for the thrust faulting . The present distribution of thermally metamorphosed Paleozoic rocks in the Ruby Mountains seems to preclude the possibility that the thrust plate originated within the Ruby Mountains . Sharp suggested a western source with displacement of from 7 to 10 miles.

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Geological Society of America Bulletin Article

Source-reported bounding extent: 39.83385008019448° to 42.00032514831621° latitude; -119.981689453125° to -114.04907226562499° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Ronald Willden, Thomas A. Hermann, T.W. Stern. 1967. Oligocene or younger thrust faulting in the Ruby Mountains, northeastern Nevada. https://doi.org/10.1130/0016-7606(1967)78%5B1345%3Aooytfi%5D2.0.co%3B2

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