Abstract

At least 14,000 feet of Cambrian to Pennsylvanian(?) strata are exposed in the Wheeler Peak and Garrison quadrangles which straddle the southern Snake Range in east-central Nevada.

Six thrust faults, not all of which have had much displacement, generally follow the shaly formations, and in places some of the thrust faults cut out several thousand feet of strata. The upper thrust plates moved relatively east-northeastward. A fence diagram and a structure contour map of one of these thrust faults show the coincidence of some of the troughs or structurally low belts in the thrust plane with areas of gouged-out underlying shaly beds. The sequence of truncation of the thrust plates indicates that successively higher plates were active as the underlying ones were essentially locked in place. Some normal faults in the widespread thrust breccia sheets are restricted to one or several thrust plates and are believed to be contemporaneous with the thrust faults. Only one major orogeny of probably late Mesozoic or early Tertiary age is necessary to explain these structures; very likely they are the near-surface expression of one major thrust zone.

Two Tertiary granitic stocks that show little contact alteration are located in areas of regional and local structural domes and have drag features along their borders that indicate a viscous magma was forcibly injected at relatively low temperature.

Several periods of movement along high-angle faults bordering the range are recorded by major unconformities in the probably late Tertiary to Recent deposits flanking the range and by various erosion surfaces.

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