By analyzing teleseismic waveforms recorded by 53 stations of Hi-Climb profile passing through the central Bangong-Nujiang suture(BNS) ,a total of 4764 high-quality receiver functions are obtained.The average crustal ...By analyzing teleseismic waveforms recorded by 53 stations of Hi-Climb profile passing through the central Bangong-Nujiang suture(BNS) ,a total of 4764 high-quality receiver functions are obtained.The average crustal thickness and Poisson's ratio beneath each station are estimated using the travel time of Ps and PpPs of the Moho.The discontinuities such as the Moho,the 410and 660-km interfaces are also studied using the common converted points(CCP) time to depth migration of receiver functions. The main results are as follows:(1) The Moho of Lhasa terrane and that of Qiangtang terrane nearby BNS are overridden and offset by～10 km.The structural geometry shows a northward uplifting and the southward deepening for the Moho of Lhasa terrane and Qiangtang terrane,respectively,which is related to the reactivated structure beneath BNS since Cenozoic era.(2) The variation range of Poisson's ratios along the profile is between 0.237 and 0.280,indicating that the crust is mainly composed of felsic and intermediate rocks.The anti-correlation between the crustal thickness and Poisson's ratio suggests that thicker crust beneath the southern Qiangtang terrane may be related to the successive thrust of felsic and intermediate rock of Lhasa terrane.(3) The thickness of the mantle transition zone along the profile remains about 255 km,implying that the tectonic activities caused by the India-Asia collision are confined to the depths above 410 km.展开更多
基金supported by the National Basic Research Program of China(Grant No.2008CB425704)
文摘By analyzing teleseismic waveforms recorded by 53 stations of Hi-Climb profile passing through the central Bangong-Nujiang suture(BNS) ,a total of 4764 high-quality receiver functions are obtained.The average crustal thickness and Poisson's ratio beneath each station are estimated using the travel time of Ps and PpPs of the Moho.The discontinuities such as the Moho,the 410and 660-km interfaces are also studied using the common converted points(CCP) time to depth migration of receiver functions. The main results are as follows:(1) The Moho of Lhasa terrane and that of Qiangtang terrane nearby BNS are overridden and offset by～10 km.The structural geometry shows a northward uplifting and the southward deepening for the Moho of Lhasa terrane and Qiangtang terrane,respectively,which is related to the reactivated structure beneath BNS since Cenozoic era.(2) The variation range of Poisson's ratios along the profile is between 0.237 and 0.280,indicating that the crust is mainly composed of felsic and intermediate rocks.The anti-correlation between the crustal thickness and Poisson's ratio suggests that thicker crust beneath the southern Qiangtang terrane may be related to the successive thrust of felsic and intermediate rock of Lhasa terrane.(3) The thickness of the mantle transition zone along the profile remains about 255 km,implying that the tectonic activities caused by the India-Asia collision are confined to the depths above 410 km.
