--> Abstract: Tertiary/Cretaceous Syntectonic Sediments of the Central Nevada Thrust Belt, by R. L. Chamberlain, D. Roeder, and A. K. Chamberlain; #91012 (1992).

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ABSTRACT: Tertiary/Cretaceous Syntectonic Sediments of the Central Nevada Thrust Belt

CHAMBERLAIN, RANDY L., Consultant, Littleton, CO, DIETRICH ROEDER, Anschutz Corporation, Denver, CO, and ALAN K. CHAMBERLAIN,* Cedar Strat Corporation, Hiko, NV

Tertiary/Cretaceous sediments (TKs) sandwiched between folded and eroded Paleozoic rocks and Tertiary volcanic rocks are distributed along the leading edge of the 400 mi-long Central Nevada Thrust Belt (CNTB). TKs were deposited in the foreland adjacent to the CNTB containing giant imbricates or duplex stacks of Devonian reservoir rocks and Mississippian source rocks. Paleocurrent indicators suggest that the drainage in the foreland was directed to the south toward the Gulf of California.

Although Nevada TKs are not as extensive as the TKs of the Utah/Wyoming thrust belt to the east, they are similar in that they are composed of basal conglomerates and overlying lacustrine limestones. Upper and lower age constraints on thrusting can be inferred from relationships of the TKs and thrusts.

The TKs thicken to several thousand feet and coarsen toward their western source. Thrust faults and the TKs become younger eastward. In some areas, the TKs contain exotic clasts. For example, conglomerates containing Receptaculites-bearing Ordovician Pogonip limestone clasts in the TKs at Monte Mountain, Timpahute Range overlie folded Mississippian limestones and shales. The nearest Pogonip outcrops are found in a hanging-wall thrust imbricate of Ordovician over Devonian, several miles to the west.

A better understanding of the distribution and composition of the TKs may provide insight into history of thrusting and into timing of hydrocarbon generation and migration. Also the distribution of the TKs may provide hints of early Tertiary paleogeography that reflect buried thrust features that are capable of trapping hydrocarbons.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)