The constraint of the Altyn Tagh fault system to growth and rise of the northern Tibetan Plateau

Category Tectonic & Seismotectonic
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Li, Haibing۱; Yang , Jingsui۱; Xu, Zhiqin۱; Paul, Tapponnier۲; Jerome, Van Der Woerd۳; Anne-Sophie, Meriaux۴
Holding Date 20 September 2008

The sinistral ductile shear zone along the Altyn Tagh fault system indicated the existence of ancient Altyn Tagh fault; Multiple Isotope dating proved that the fault developed in Triassic, yielded intensely sinistral strike-slip in Jurassic and Cretaceous, then reacted and became the present fault system after the collision between the India plate and the Eurasia plate. The whole evolvement should contain the activity and movement of both ancient and current Altyn Tagh fault system. Main displacement of the fault occurred in (1) 245-220 Ma; (2) 180-140 Ma; (3) 120-100 Ma; (4) 90-80 Ma; (5) 60-45 Ma); (6) Paleocene-Miocene; (7) Pliocene-Pleistocene; and (8) Holocene. As a result of the strike slip displacement, a series of thrust faults and normal faults occurred along the Altyn Tagh fault system indicating the rise during the strike slip, As a result of the strike-slip displacement, a series of thrust fault and normal fault occurred along the Altyn Tagh fault system and indicating the rise in the strike-slip. The volcanic activities since the Cretaceous at both east and west ends of the Altyn Tagh fault system were also the results of the reactivation. Basing on the deformation structures, isotope chronological and paleomagnetic data, during the sinistral strike-slip of the ancient Altyn Tagh fault system, the southeastern block clockwise rotated, and the thrust fault developed in the northeastern part made the pre-Cretaceous geological bodies rise and form the nascent Qilian Mountains. The reactivation of the fault in the Cenozoic created northern border of the Qinghai-Tibet plateau. The variation of the slip rate along the Altyn Tagh fault system indicated that part of the energy has transformed into the thrust faults in both sides of the fault; along these faults crust was shortened, old geological bodies rose and built a series of mountain ranges. The isotope chronological data, slip rate and accumulative displacement revealed the evolvement from middle to both sides of the Altyn Tagh fault system and several mountains formed in this period including from north to south the Qilian mountains, the Daxueshan mountains, the Danghenanshan mountains, the North Qaidam mountains, the Qiman Tagh mountains and the Kunlun mountains, which indicate that the Altyn Tagh fault system developed or controlled the "basin-range" geomorphic features in northern part of the Qinghai-Tibet plateau and constrained growth and rise of northern Qinghai-Tibet Plateau.