Northwest Basin and Range Geothermal Region

The Basin and Range Province in northwestern Nevada and northeastern California is characterized by late Cretaceous - early Cenozoic regional erosion, Oligocene - Miocene volcanism, and subsequent late Miocene extension. Extensional faulting in northwestern Nevada began everywhere at 12 Ma and has continued up to the present. Faulting in the Warner Range in northeastern California can only be constrained to have begun between 14 and 3 Ma, but may represent westward migration of Basin and Range extension during the Pliocene. Compared to the many parts of the Basin and Range in central and southern Nevada, extension in northwestern Nevada began more recently, is of lesser total magnitude, and was accommodated entirely by high-angle normal faults. Fission-track data document Late Cretaceous unroofing of Cretaceous (115 –100 Ma) granitic basement rocks in northwestern Nevada, followed by a long period of relative tectonic quiescence that persisted through Oligocene and Miocene volcanism until the onset of Basin and Range extension at 12 Ma. The low magnitude of extension (12%) and early Tertiary stability suggest that the modern 31 km thick crust in northwestern Nevada was only slightly thicker (35 km) prior to extension at 12 Ma, and was no thicker than 38 km in the Late Cretaceous. This stands in contrast to other parts of the Basin and Range, where the crust was thickened to at least 45 to 50 km by Cretaceous thrusting and subsequently thinned to 30 km by large magnitude (>50%) extension. Cenozoic Tectonic Evolution of the Basin and Range Province in Northwestern Nevada ^[1]
Assessment of Moderate- and High-Temperature Geothermal Resources of the United States^[2]