Sonoma orogeny

Sonoma orogeny, an orogenic event that affected the eugeosynclinal (deepwater) portion of the Cordilleran Geosyncline in northwestern Nevada occurring between Middle Permian and Early Triassic times (270 million to 245 million years ago). Evidence for the orogeny consists of an angular unconformity between Late Permian volcanics and older rocks, and a thrust fault, the Golconda Thrust, that has moved pre-Late Permian rocks eastward for many kilometres.