Global Positioning System measurements from eastern Tibet and their implications for India/Eurasia intercontinental deformation

We present and interpret Global Positioning System (GPS) measurements of crustal motions for the period 1991–1998 for a network encompassing the eastern part of the Tibetan Plateau and its foreland. Relative to a Eurasian frame defined by minimizing the velocities of 16 GPS stations in Europe, central Asia, and Siberia, stations within all parts of the plateau foreland in south China move 6–10 mm/yr east-southeast, indicating that the eastward movement within the plateau is part of a broader eastward movement that involves the plateau and its eastern and northern foreland. North of the plateau, foreland stations move northeastward at ∼10 mm/yr, indicating that the northern boundary of the deformation zone lies north of the plateau. With this realization of a Eurasian frame, the velocity of the GPS station at Bangalore in southern India implies that the northward motion of India is 5–12 mm/yr slower than that predicted from the NUVEL-1A plate reconstruction. Viewed relative to the South China Block, stations of the northeast plateau, bounded on the north by the Qilian Shan and the Altyn Tagh fault, move NNE to NE with velocities ranging from 19 mm/yr within the plateau to 5–11 mm/yr in its foreland. The Altyn Tagh fault shows left-lateral slip of ∼10 mm/yr at 95°E and shortening across the fault of <5 mm/yr. Stations south and west of the Xianshuihe/Xiaojiang fault system define a crustal fragment rotating clockwise at ∼10 mm/yr relative to the South China Block around the eastern Himalayan syntaxis. The GPS measurements indicate no significant shortening (< 3 mm/yr) within the Longmen Shan of the central eastern plateau and its adjacent foreland, although the Longmen Shan rise over 6 km in <100 km horizontal distance. Geological studies indicate that the deformational field was established diachronously in late Miocene to Pliocene time, was characterized by no east-west shortening of Tibetan crust, and has an inhomogeneous style of deformation resulting from a balance of different tectonic processes.

[1]  B. Burchfiel,et al.  Motion of the Pacific plate relative to Eurasia and its potential relation to Cenozoic extension along the eastern margin of Eurasia , 1995 .

[2]  K. Whipple,et al.  Neotectonics of the Min Shan, China: Implications for mechanisms driving Quaternary deformation along the eastern margin of the Tibetan Plateau , 2000 .

[3]  B. Burchfiel,et al.  Late Cenozoic tectonic evolution of the Ningxia-Hui Autonomous Region, China , 1990 .

[4]  R. King,et al.  Geodetic measurement of crustal motion in southwest China , 1997 .

[5]  G. Peltzer,et al.  Magnitude of Late Quaternary Left-Lateral Displacements Along the North Edge of Tibet , 1989, Science.

[6]  Demitris Paradissis,et al.  Global Positioning System constraints on plate kinematics and dynamics in the eastern Mediterranean and Caucasus , 2000 .

[7]  J. Brock.  Force associated with the Temperature Gradient on a Small Particle suspended in a Plasma , 1964, Nature.

[8]  P. Tapponnier,et al.  Northeastward growth of the Tibet plateau deduced from balanced reconstruction of two depositional areas: The Qaidam and Hexi Corridor basins, China , 1998 .

[9]  C. Boucher,et al.  The ITRF96 realization and its associated velocity field , 1998 .

[10]  Wen-yao Zhu,et al.  Global plate motion models incorporating the velocity field of ITRF96 , 1999 .

[11]  J. Freymueller,et al.  Geodetic evidence for a low slip rate in the Altyn Tagh fault system , 2000, Nature.

[12]  B. Burchfiel,et al.  Tectonics of the Longmen Shan and Adjacent Regions, Central China , 1995 .

[13]  G. Peltzer,et al.  Rate of left-lateral movement along the easternmost segment of the Altyn Tagh fault, east of 96°E (China) , 1996 .

[14]  B. Windley,et al.  Late Cenozoic transpression in southwestern Mongolia and the Gobi Altai-Tien Shan connection , 1996 .

[15]  Walter H. F. Smith,et al.  New version of the generic mapping tools , 1995 .

[16]  J. Mercier,et al.  Active faulting in and along the Qinling Range (China) inferred from SPOT imagery analysis and extrusion tectonics of south China , 1995 .

[17]  E. Hauksson,et al.  Focal mechanisms and aftershock locations of the Songpan earthquakes of August 1976 in Sichuan, China , 1984 .

[18]  J. Dewey,et al.  The tectonic evolution of the Tibetan Plateau , 1988, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[19]  T. Herring,et al.  Relatively recent construction of the Tien Shan inferred from GPS measurements of present-day crustal deformation rates , 1996, Nature.

[20]  W. Holt,et al.  Earthquake strain rates and instantaneous relative motions within central and eastern Asia , 1995 .

[21]  M. Watkins,et al.  Glacial isostatic adjustment observed using very long baseline interferometry and satellite laser ranging geodesy , 1999 .

[22]  B. Burchfiel,et al.  Late Cenozoic to Holocene deformation in southwestern Sichuan and adjacent Yunnan, China, and its role in formation of the southeastern part of the Tibetan Plateau , 2000 .

[23]  Wang,et al.  Surface Deformation and Lower Crustal Flow in Eastern Tibet , 1997, Science.

[24]  T. Wallace,et al.  The active tectonics of the eastern Himalayan syntaxis and surrounding regions , 1991 .

[25]  G. Beutler,et al.  Geodynamics - Tracking satellites to monitor global change , 1993 .

[26]  B. Burchfiel,et al.  Amount and style of late Cenozoic deformation in the Liupan Shan area, Ningxia autonomous region, China , 1991 .

[27]  P. Molnar,et al.  Cenozoic Tectonics of Asia: Effects of a Continental Collision: Features of recent continental tectonics in Asia can be interpreted as results of the India-Eurasia collision. , 1975, Science.

[28]  Peter Molnar,et al.  Mantle dynamics, uplift of the Tibetan Plateau, and the Indian Monsoon , 1993 .

[29]  B. Burchfiel,et al.  Tectonic of Asia 50 years after the death of Emile Argand , 1991 .

[30]  C. R. Allen,et al.  Field study of a highly active fault zone: The Xianshuihe fault of southwestern China , 1991 .

[31]  Peter Molnar,et al.  Intracrustal detachment within zones of continental deformation , 1989 .

[32]  Leigh H. Royden,et al.  Topographic ooze: Building the eastern margin of Tibet by lower crustal flow , 2000 .

[33]  Bertrand Meyer,et al.  Crustal thickening in Gansu‐Qinghai, lithospheric mantle subduction, and oblique, strike‐slip controlled growth of the Tibet plateau , 1998 .

[34]  R. Clayton,et al.  Notes on Sedimentary Basins in China Report of the American Sedimentary Basins Delegation to the People's Republic of China , 1986 .

[35]  J. Mercier,et al.  Extension in the graben systems around the Ordos (China), and its contribution to the extrusion tectonics of south China with respect to Gobi-Mongolia , 1998 .

[36]  Peter Molnar,et al.  Bounds on the Holocene Slip Rate of the Haiyuan Fault, North-Central China , 1988, Quaternary Research.

[37]  R. Bürgmann,et al.  Kinematics of the India-Eurasia collision zone from GPS measurements , 1999 .

[38]  Robert W. King,et al.  Estimating regional deformation from a combination of space and terrestrial geodetic data , 1998 .

[39]  Leigh H. Royden,et al.  Late Cenozoic Xianshuihe-Xiaojiang, Red River, and Dali Fault Systems of Southwestern Sichuan and Central Yunnan, China , 1998 .

[40]  Frederick J. Ryerson,et al.  Postglacial left slip rate and past occurrence of M≥8 earthquakes on the Western Haiyuan Fault, Gansu, China , 1999 .

[41]  M. Caffee,et al.  Holocene left-slip rate determined by cosmogenic surface dating on the Xidatan segment of the Kunlun fault (Qinghai, China) , 1998 .

[42]  J. Freymueller,et al.  GPS measurements of present-day convergence across the Nepal Himalaya , 1997, Nature.

[43]  Richard G. Gordon,et al.  Effect of recent revisions to the geomagnetic reversal time scale on estimates of current plate motions , 1994 .

[44]  J. Nábělek,et al.  Present-day deformation of the Qaidam basin with implications for intra-continental tectonics , 1999 .

[45]  W. Peltier,et al.  Ice Age Paleotopography , 1994, Science.

[46]  D. Jackson,et al.  Contemporary crustal deformation in east Asia constrained by Global Positioning System measurements , 2000 .

[47]  B. Pluijm,et al.  Paleomagnetic constraints on Siluro-Devonian Laurentian margin tectonics from northern Appalachian volcanics , 1998 .

[48]  R. Armijo,et al.  Quaternary extension in southern Tibet: Field observations and tectonic implications , 1986 .

[49]  L. Wang,et al.  Displacement and timing along the northern strand of the Altyn Tagh fault zone , 1997 .

[50]  T. Sagiya,et al.  Coseismic slip resolution along a plate boundary megathrust: The Nankai Trough, southwest Japan , 1999 .

[51]  Bertrand Meyer,et al.  Active thrusting and folding in the Qilian Shan, and decoupling between upper crust and mantle in northeastern Tibet , 1990 .

[52]  Jeffrey T. Freymueller,et al.  Global Plate Velocities from the Global Positioning System , 1997 .