Crustal and upper-mantle structure of the southeastern Tibetan Plateau from joint analysis of surfacewave dispersion and receiver functions

作者:Li, MK (Li, Mengkui)^{[ 1 ]} ; Zhang, SX (Zhang, Shuangxi)^{[ 1,2,3 ]} ; Wang, F (Wang, Fang)^{[ 1 ]} ; Wu, TF (Wu, Tengfei)^{[ 1 ]} ; Qin, WB (Qin, Weibing)^{[ 1 ]}

JOURNAL OF ASIAN EARTH SCIENCES

DOI: 10.1016/j.jseaes.2015.12.002

出版年: MAR 1 2016

文献类型:Article

摘要

Researches on the southeastern Tibetan Plateau provide important insights into the tectonic evolution of the Tibetan Plateau. In this study, we have constructed a high-resolution 3D shear-wave velocity model through joint inversion of receiver functions and surface wave dispersion data. The crustalthickness and Poisson's ratio models are first determined by H-k stacking of receiver functions. The crustal thickness changes from 30 km in the south to 62 km in the north, presenting strong lateral variations. The fundamental mode of Rayleigh wave dispersion data spanning periods from 8 to 65 s were then jointly used to constraint the absolute shear-wave velocity. The shear-wave velocity structure shows lateral variations. There are low velocity zones distributed in the crust and upper mantle. Two continuously distributed low velocity zones are clearly presented in the middle-to-lower crust, which extend from north toward southeast and southwest, respectively, joining together in southern Yunnan. In this study, we deduced the migration model of soft materials in middle-to-lower crust in southeastern Tibetan Plateau, which explains that the resistance from Sichuan Basin separates the flowing materials from Tibetan Plateau into southeast and northwest branches. They flow along the west margin of Sichuan Basin and then extrude out from northeastern and southeastern Tibetan Plateau respectively. The southeast branch is blocked and cannot flow in the entire crust. It is limited in a certain range of depths and channels. The two low velocity zones in this study possibly present two flow channels of the middle-to-lower crustal materials extruded from the TibetanPlateau. (C) 2015 Elsevier Ltd. All rights reserved.

作者关键词:Southeastern Tibetan Plateau; Joint analysis; Receiver function; Surface wave dispersion; Crustal flow

KeyWords Plus:H-KAPPA STACKING; STRUCTURE BENEATH; SE TIBET; VELOCITY STRUCTURE; EASTERN TIBET; SEISMIC ANISOTROPY; YUNNAN REGION; DEFORMATION; TOMOGRAPHY; INVERSION

通讯作者地址: Zhang, SX (通讯作者)

地址:

电子邮件地址:shxzhang@sgg.whu.edu.cn

基金资助机构授权号