Mississippian Stratigraphy and Tectonics of East-Central Nevada: Post-Antler Orogenesis

TREXLER, JAMES, and PATRICIA CASHMAN, University of Nevada, Reno, NV

High-resolution stratigraphic studies in the Diamond Mountains are revealing details of tectonic deformation and basin filling that post-date the emplacement of the Antler allochthon and predate the Sonoma orogeny. Antler foreland-basin strata were deformed, uplifted, and eroded in the middle Mississippian, and a late Mississippian successor basin was established that persisted into the Pennsylvanian.

The Antler peripheral foreland basin of eastern Nevada formed in the early Mississippian as a result of obduction of an accretionary prism onto the western edge of the North American craton. This basin filled with submarine-fan sediments shed from the west that range in age from late Osagean to middle Meramecian or slightly younger. In the Diamond Mountains, these strata are deformed into open folds, and are truncated by a regional unconformity. The unconformity documents an uplift and erosion event in the late Meramecian that we have called the Diamond Mountain phase of deformation. Oldest strata above the unconformity are early Chesterian.

Renewed subsidence in Chesterian time resulted in formation of a wide and shallow successor basin, bounded on the west by the relict Antler highland, and on the east by a siliciclastic shelf and the craton margin. This successor basin was filled with recycled Antler foreland sediments and intrabasinal shelf carbonates. Reworked Antler clastics were distributed throughout the basin by a system of mainly south-flowing fluvial and deltaic distributaries. This mixed clastic/carbonate basin persisted well into the Pennsylvanian.

AAPG Search and Discovery Article #91009©1991 AAPG-SEPM-SEG-SPWLA Pacific Section Annual Meeting, Bakersfield, California, March 6-8, 1991 (2009)