Nonmarine sedimentary rocks of Tertiary age in the Lake Mead region, southeastern Nevada and northwestern Arizona.

Abstract

The character, age, nomenclature, and geologic history of Tertiary strata throughout the Lake Mead region are examined with respect to the history of development of the Basin and Range Province. The interpreted history suggests that a widespread but shallow basin formed there about 20-17 m.y. ago over gently deformed rocks east of the Sevier thrust terrane. A deep, fault-bounded trough developed after that time and lasted until about 13.5 m.y. ago, but this trough did not have the trend of shape of later Basin and Range basins. Lateral slip faults fragmented both of these early basins and strongly controlled sedimentation until about 12 m.y. ago, when horsts and grabens associated with Basin and Range structure began to develop.

21 samples from this reference