ABSTRACT: Monte Mountain Thrust, Additional Confirmation of the Central Nevada Thrust Belt
Alan K. Chamberlain, Randy L. Chamberlain
The Monte Mountain thrust, a newly identified thrust exposed in the Timpahute Range, east-central Nevada, places porous Devonian reservoir rocks over rich Mississippian source rocks that are at the peak oil-generating window. The thrust provides insurmountable evidence of a thrust model that may lead to discovery of giant oil and gas fields along the 400 mi long Central Nevada Thrust Belt. The Timpahute Range lies a little over 50 mi on strike to the south of the prolific Grant Canyon field.
Scattered remnants of the north-trending thrust belt are obscured by parallel valleys of Tertiary valley fill and volcanics. The fact that the east-west-trending Timpahute Range could contain exposures of the north-south-trending central Nevada thrust belt attracted us to the range. Familiarity with the stratigraphic section led to the discovery of the thrust.
As much as 750 ft of Devonian Guilmette sandstones, in the hanging wall just above the thrust contact, have been erroneously mapped as Mississippian Scotty Wash sandstones. These Devonian sandstones could be excellent reservoir rocks. Sandstones in the Guilmette increase in thickness westward. East vergent thrusting has juxtaposed plates of thicker Guilmette sandstones with plates of thinner sandstones. Reconstruction of Devonian paleogeography provides a clue to the amount of displacement along thrust boundaries.
AAPG Search and Discovery Article #91002©1990 AAPG Rocky Mountain Section Meeting, Denver, Colorado, September 16-19, 1990