Seismic reflection evidence for two-phase development of Tertiary basins from east-central Nevada

Two east-west seismic reflection profiles crossing Antelope Valley, Smokey Valley, Railroad Valley, and Big Sand Springs Valley in east-central Nevada demonstrate the evolution of Tertiary basin extension in the Basin and Range Province from broad sags to narrow, fault-bounded basins. Two distinct phases of basin development occurred, separated by a regional unconformity. The early phase is characterized by development of a broad symmetric basin riddled with many small offset normal faults. The later phase shows a narrowing of the basin and subsidence along one dominant structure, an apparent planar normal fault. -from Authors