Seismic reflection evidence of crustal duplexing and lithospheric underthrusting beneath the western Qilian Mountains,northeastern margin of the Tibetan Plateau

作者：Xingfu HUANG,Rui GAO,Wenhui LI,Xiaosong XIONG

摘要：The geological processes responsible for outward growth of the Tibetan Plateau are debated.The Qilian Mountains on the northeastern margin of the plateau comprise one of the youngest structural components of the plateau whose understanding is key to deciphering the broader geological evolution of the region.Here,based on a reprocessed deep seismic profile which was originally collected during the 1990 s across the northeast margin of the western Qilian Mountains and previous geological and geophysical data,we find evidence for decoupled crustal deformation that was partitioned by a decollement,in which lowercrustal deformation featured by local duplexing preceded upper-crustal deformation featured by imbricate thrusts.Furthermore,we propose that the Asian lithospheric mantle is being underthrust beneath the western Qilian Mountains,as inferred from patterns of lower crustal deformation which is marked by the Moho geometry.Integrating these results yields a better understanding of lithospheric deformation of western Qilian Mountains,northeastern margin of the plateau during the Cenozoic.

发文机构：School of Earth Science and Engineering Southern Marine Science and Engineering Guangdong Laboratory（Zhuhai） Key L aboratory of Deep-Earth Dynamics SinoProbe Center

关键词：SeismicreflectionCrustalduplexingLithosphericunderthrustingQilianMountainsNETibetanPlateau

分类号： P31[天文地球—固体地球物理学]