Thomas A. Hermann
T.W. Stern
Ronald Willden
1967
<p><span>A klippe of unmetamorphosed Devonian carbonate rocks rests on the Harrison Pass intrusive body south of Toyn Creek </span>in<span> the central </span>Ruby<span> </span>Mountains<span>, Elko County, </span>Nevada<span>. 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 </span>thrust<span> 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 </span>Oligocene<span> or </span>younger<span> 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 </span>Oligocene<span> for the </span>thrust<span> </span>faulting<span>. The present distribution of thermally metamorphosed Paleozoic rocks </span>in<span> the </span>Ruby<span> </span>Mountains<span> seems to preclude the possibility that the </span>thrust<span> plate originated within the </span>Ruby<span> </span>Mountains<span>. Sharp suggested a western source with displacement of from 7 to 10 miles. </span></p>
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10.1130/0016-7606(1967)78[1345:OOYTFI]2.0.CO;2
en
Geological Society of America
Oligocene or younger thrust faulting in the Ruby Mountains, northeastern Nevada
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