Two-phase Neogene extension in the northwestern Basin and Range recorded in a single thermochronology sample

Abstract

Research Article| August 01, 2008 Two-phase Neogene extension in the northwestern Basin and Range recorded in a single thermochronology sample Joseph P. Colgan; Joseph P. Colgan * 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA *E-mail: jcolgan@usgs.gov. Search for other works by this author on: GSW Google Scholar David L. Shuster; David L. Shuster 2Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, California 94709, USA Search for other works by this author on: GSW Google Scholar Peter W. Reiners Peter W. Reiners 3Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Joseph P. Colgan * 1U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA David L. Shuster 2Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, California 94709, USA Peter W. Reiners 3Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85721, USA *E-mail: jcolgan@usgs.gov. Publisher: Geological Society of America Received: 25 Feb 2008 Revision Received: 22 Apr 2008 Accepted: 04 May 2008 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2008 Geological Society of America Geology (2008) 36 (8): 631–634. https://doi.org/10.1130/G24897A.1 Article history Received: 25 Feb 2008 Revision Received: 22 Apr 2008 Accepted: 04 May 2008 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Joseph P. Colgan, David L. Shuster, Peter W. Reiners; Two-phase Neogene extension in the northwestern Basin and Range recorded in a single thermochronology sample. Geology 2008;; 36 (8): 631–634. doi: https://doi.org/10.1130/G24897A.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract We use a combination of apatite 4He/3He, (U-Th)/He, and fission-track thermochronology to date slip on the Surprise Valley fault in northeastern California by analyzing a single sample from the Warner Range in the footwall of the fault. This sample, a granitic clast from a conglomerate, yielded a fission-track age of 11.6 ± 2.8 Ma and a (U-Th)/He age of 3.02 ± 0.52 Ma. Geologic relationships indicate that this sample was buried to a depth of ~3.3 km prior to exhumation during slip on the Surprise Valley fault. Fission-track age and length data indicate that the sample was fully reset (>120 °C) prior to exhumation, which began sometime after 14 Ma. A single aliquot of nine apatite grains was step-heated for 4He/3He analysis; modeling of the resulting 4He distribution indicates that cooling from >80 °C to ~20 °C occurred between 3 and 1 Ma. Interconsistent time-temperature (t-T) solutions to the combined 4He/3He, (U-Th)/He, and fission-track data require two distinct periods of cooling, consistent with non-continuous slip on the Surprise Valley fault. Early cooling and fault slip took place between 14 and 8 Ma, followed by more recent fault slip ca. 3 Ma. This timing is consistent with both local geologic relationships and with the regional timing of faulting along the western margin of the Basin and Range Province. These data demonstrate the resolving power of combined fission-track, (U-Th)/He, and 4He/3He thermochronometric data to extract low-temperature t-T information from a single sample close to Earth's surface. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.