|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095-1567, USA
2 Lawrence Livermore National Laboratory, Livermore, California 94550, USA
3 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
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.
Key Words: Himalayas • kinematics • metamorphic core complex • strike-slip faults • Tibetan plateau
This article has been cited by other articles:
|
|
 |
|
  M. J. Jessup, D. L. Newell, J. M. Cottle, A. L. Berger, and J. A. Spotila Orogen-parallel extension and exhumation enhanced by denudation in the trans-Himalayan Arun River gorge, Ama Drime Massif, Tibet-Nepal Geology, July 1, 2008; 36(7): 587 - 590. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. L. Wells and T. D. Hoisch The role of mantle delamination in widespread Late Cretaceous extension and magmatism in the Cordilleran orogen, western United States GSA Bulletin, May 1, 2008; 120(5-6): 515 - 530. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Murphy Isotopic characteristics of the Gurla Mandhata metamorphic core complex: Implications for the architecture of the Himalayan orogen Geology, November 1, 2007; 35(11): 983 - 986. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N.S. Raterman, E. Cowgill, and D. Lin Variable structural style along the Karakoram fault explained using triple-junction analysis of intersecting faults Geosphere, April 1, 2007; 3(2): 71 - 85. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. M. Robinson, P. G. DeCelles, and P. Copeland Tectonic evolution of the Himalayan thrust belt in western Nepal: Implications for channel flow models GSA Bulletin, July 1, 2006; 118(7-8): 865 - 885. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. C. Thiede, J. R. Arrowsmith, B. Bookhagen, M. McWilliams, E. R. Sobel, and M. R. Strecker Dome formation and extension in the Tethyan Himalaya, Leo Pargil, northwest India GSA Bulletin, May 1, 2006; 118(5-6): 635 - 650. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M.-L. Chevalier, F. J. Ryerson, P. Tapponnier, R. C. Finkel, J. Van Der Woerd, L. Haibing, and L. Qing Slip-Rate Measurements on the Karakorum Fault May Imply Secular Variations in Fault Motion Science, January 21, 2005; 307(5708): 411 - 414. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Indian punch rifts Tibet Geology, November 1, 2004; 32(11): 993 - 996.
|
|
|
|
|
|
A. C. Robinson, A. Yin, C. E. Manning, T. M. Harrison, S.-H. Zhang, and X.-F. Wang Tectonic evolution of the northeastern Pamir: Constraints from the northern portion of the Cenozoic Kongur Shan extensional system, western China GSA Bulletin, July 1, 2004; 116(7-8): 953 - 973. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. M. Davis, J. C. Aitchison, Badengzhu, and L. Hui Conglomerates record the tectonic evolution of the Yarlung-Tsangpo suture zone in southern Tibet Geological Society, London, Special Publications, January 1, 2004; 226(1): 235 - 246. [Abstract] [PDF]
|
|
|
|
 |
|
 L. DING, P. KAPP, D. ZHONG, and W. DENG Cenozoic Volcanism in Tibet: Evidence for a Transition from Oceanic to Continental Subduction J. Petrology, October 1, 2003; 44(10): 1833 - 1865. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M.A. Murphy and A. Yin Structural evolution and sequence of thrusting in the Tethyan fold-thrust belt and Indus-Yalu suture zone, southwest Tibet GSA Bulletin, January 1, 2003; 115(1): 21 - 34. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Aitchison, A. M. Davis, A. V. Abrajevitch, J. R. Ali, Badengzhu, J. Liu, H. Luo, I. R. C. McDermid, and S. V. Ziabrev Stratigraphic and sedimentological constraints on the age and tectonic evolution of the Neotethyan ophiolites along the Yarlung Tsangpo suture zone, Tibet Geological Society, London, Special Publications, January 1, 2003; 218(1): 147 - 164. [Abstract] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
