Fragments of hot and metasomatized mantle lithosphere in Middle Miocene ultrapotassic lavas,southern Tibet
会议名称：《中国科学院地质与地球物理研究所第11届（2011年度）学术年会》
会议日期：2012年
学科分类：070801[理学-固体地球物理学] 07[理学] 0708[理学-地球物理学]
基 金：supported by funds from National Natural Science Foundation of China(40873024, 40873023) Chinese Academy of Sciences(KZCX2EW -109)
摘 要：Uplift of the Tibetan Plateau and its influence on our global climate have been the focus of numerous *** potassic to ultrapotassic volcanism is widespread in southern Tibet and has been generally attributed to convective removal of collision-thickened Asian lithosphere,which is also responsible for the uplift of the *** implicit assumption of this model is the existence of a hydrous,metasomatized(i.e.,phlogopite bearing) lithospheric mantle that remained after the convective thinning and was subsequently heated to form small-volume *** such a lithospheric mantle was present in the Miocene,it implies further change since that time,as seismic velocities indicate that cold and strong upper mantle occurs beneath the thick crust in southern *** we describe peridotite xenoliths entrained in Middle Miocene ultrapotassic lavas from Sailipu,southern *** results suggest the existence of hot,highly metasomatized lithospheric mantle beneath southern Tibet during the Middle Miocene,and thus support the idea that convective thinning of the lithosphere was responsible for the uplift of the *** relict mantle was later removed or squeezed northward by the underthrusting Indian continental lithosphere,which terminated magmatism in southern Tibet and played a role in creating the entire plateau.