ANTLER OROGENY

a mountain-building event in Late Devonian and Mississippian time (about 340,000,000 to 350,000,000 years ago) that affected a linear belt in the Cordilleran Geosyncline, extending from the CaliforniaNevada border northward through the central part of Nevada into Idaho. The term Antler Orogenic Belt, and formerly Manhattan Geanticline, is applied to the deformed rocks produced by this orogeny. Evidence for the Antler orogeny consists of the widespread extent of coarse clastic sediments of Mississippian and Early Pennsylvanian age east and west of the belt and the development of a very prominent eastward-moving thrust fault in Early Mississippian time, the Roberts Mountain Thrust.