RESEARCH ON THE FINE CRUSTAL STRUCTURE OF THE NORTHERH QILIAN-NEXI CORRIDOR BY DEEP SEISMIC REFLECTION
WU XUAN-ZHI; WU CHUN-LING; LU JIE ; WU JIE( Institute of Mineral Deposits, CAGS, Beijing 100037)( Lithosphere Research Center, CAGS, Beijing 100037)( 562 Comprehensive Research Brigade, CAGS, Sanhe, Hebai 101601)
A 94 kilometer long deep seismic reflection profile was completed from northern Qilianmountain to Hexi corridor in Gansu province of China. The Moho is about 40─50 km deepand tilts southwards to Qilian mountain. The North Qilian Front Thrust is also dippingsouthwards, steeply in shallow with decreasing dip to merge with a reflection energy zone at3. 5─4 s, probably coming from a detechment. The Altun fault zone is likely extending eastto Kuantanshan, also inclined southerly and reaches the lower crust. It is the Altun faultzone and the North Qilian Front Thrust which absorb the press stress in Qilian regioncaused by the indian plate's northward movement.