Rapid middle Miocene extension and unroofing of the southern Ruby Mountains, Nevada

By: , and 



Paleozoic rocks in the northern Ruby Mountains were metamorphosed during Mesozoic crustal shortening and Cenozoic magmatism, but equivalent strata in the southern Ruby Mountains were never buried deeper than stratigraphic depths prior to exhumation in the footwall of a west dipping brittle normal fault. In the southern Ruby Mountains, Miocene sedimentary rocks in the hanging wall of this fault date from 15.2 to 11.6 Ma and contain abundant detritus from the Paleozoic section. Apatite fission track and (U-Th)/He samples of the Eocene Harrison Pass pluton record rapid cooling that peaked ca. 17–15 Ma, while apatite fission track data from Jurassic plutons east and west of the southern Ruby Mountains indicate near-surface temperatures (<60°C) since the Cretaceous. We interpret these data to record rapid unroofing of the southern Ruby Mountains during slip on the west dipping brittle detachment between 17–16 and 10–12 Ma, followed by minor high-angle faulting. We interpret published Oligocene to early Miocene K-Ar biotite and zircon fission track dates from the Harrison Pass pluton to be partially reset rather than to directly record fault slip. Our new data, together with published data on the distribution and composition of Miocene basin fill, suggest that rapid middle Miocene slip took place on the west dipping brittle detachment that bounds the Ruby Mountains and East Humboldt Range for 150 km along strike. This fault was thus active during a period of rapid extension (ca. 17–15 to 12–10 Ma) documented widely across the northern Basin and Range Province.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Rapid middle Miocene extension and unroofing of the southern Ruby Mountains, Nevada
Series title Tectonics
DOI 10.1029/2009TC002655
Volume 29
Year Published 2010
Language English
Publisher American Geophysical Union
Publisher location Washington, D.C.
Contributing office(s) Geology and Geophysics Science Center
Description 38 p.; TC6022
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Tectonics
Country United States
State Nevada
Other Geospatial Ruby Mountains
Google Analytic Metrics Metrics page
Additional publication details