Structural evolution of the Gurla Mandhata detachment system, southwest Tibet: Implications for the eastward extent of the Karakoram fault system

Research Article| April 01, 2002 Structural evolution of the Gurla Mandhata detachment system, southwest Tibet: Implications for the eastward extent of the Karakoram fault system M.A. Murphy; M.A. Murphy 1Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095-1567, USA Search for other works by this author on: GSW Google Scholar An Yin; An Yin 1Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095-1567, USA Search for other works by this author on: GSW Google Scholar P. Kapp; P. Kapp 1Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095-1567, USA Search for other works by this author on: GSW Google Scholar T.M. Harrison; T.M. Harrison 1Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095-1567, USA Search for other works by this author on: GSW Google Scholar C.E. Manning; C.E. Manning 1Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095-1567, USA Search for other works by this author on: GSW Google Scholar F.J. Ryerson; F.J. Ryerson 2Lawrence Livermore National Laboratory, Livermore, California 94550, USA Search for other works by this author on: GSW Google Scholar Ding Lin; Ding Lin 3Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China Search for other works by this author on: GSW Google Scholar Guo Jinghui Guo Jinghui 3Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China Search for other works by this author on: GSW Google Scholar GSA Bulletin (2002) 114 (4): 428–447. https://doi.org/10.1130/0016-7606(2002)114<0428:SEOTGM>2.0.CO;2 Article history received: 25 Sep 2000 rev-recd: 22 Aug 2001 accepted: 26 Sep 2001 first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation M.A. Murphy, An Yin, P. Kapp, T.M. Harrison, C.E. Manning, F.J. Ryerson, Ding Lin, Guo Jinghui; Structural evolution of the Gurla Mandhata detachment system, southwest Tibet: Implications for the eastward extent of the Karakoram fault system. GSA Bulletin 2002;; 114 (4): 428–447. doi: https://doi.org/10.1130/0016-7606(2002)114<0428:SEOTGM>2.0.CO;2 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 SocietyGSA Bulletin Search Advanced Search Abstract Field mapping and geochronologic and thermobarometric analyses of the Gurla Mandhata area, in southwest Tibet, reveal major middle to late Miocene, east-west extension along a normal-fault system, termed the Gurla Mandhata detachment system. The maximum fault slip occurs along a pair of low-angle normal faults that have caused significant tectonic denudation of the Tethyan Sedimentary Sequence, resulting in juxtaposition of weakly metamorphosed Paleozoic rocks and Tertiary sedimentary rocks in the hanging wall over amphibolite-facies mylonitic schist, marble, gneisses, and variably deformed leucogranite bodies in the footwall. The footwall of the detachment fault system records a late Miocene intrusive event, in part contemporaneous with top-to-the-west ductile normal shearing. The consistency of the mean shear direction within the mylonitic footwall rocks and its correlation with structurally higher brittle normal faults suggest that they represent an evolving low-angle normal-fault system. 40Ar/39Ar data from muscovite and biotite from the footwall rocks indicate that it cooled below 400 °C by ca. 9 Ma. Consideration of the original depth and dip angle of the detachment fault prior to exhumation of the footwall yields total slip estimates between 66 and 35 km across the Gurla Mandhata detachment system. The slip estimates and timing constraints on the Gurla Mandhata detachment system are comparable to those estimated on the right-slip Karakoram fault system, to which it is interpreted to be kinematically linked. Moreover, the mean shear-sense direction on both the Karakoram fault and the Gurla Mandhata detachment system overlap along the intersection line between the mean orientations of the faults, which further supports a kinematic association. If valid, this interpretation extends previous results that the Karakoram fault extends to mid-crustal depths. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.