辽西中生代的壳幔过渡带的形成、破坏与改造  

Formation,destruction and deformation of the Mesozoic crust-mantle transition zone in west Liaoning province,China

作　　者：邵济安[1] 卢造勋[2] 路凤香[3] 袁学诚[4] 

机构地区：[1]北京大学地球与空间科学学院,北京1000871 [2]辽宁省地震局,沈阳110031 [3]中国地质大学,武汉430074 [4]中国地质科学院,北京100037

出　　处：《岩石学报》2006年第12期2825-2832,共8页Acta Petrologica Sinica

基　　金：国家自然科学基金(编号40372103);中国科学院矿产资源研究重点实验室资助项目.

摘　　要：利用火成岩及其携带的捕虏体的岩石学、年代学等研究成果,反演辽西中生代时期的壳幔相互作用,重塑这时期的壳幔边界组成。对应于中生代活跃的壳幔相互作用,辽西义县-北票一带理论上应该存在一个发育的壳幔过渡带。然而现今的各种地球物理研究显示辽西的莫霍面是清晰的间断面,其上、下地震波速变化从6.5～6.7km/s 截然变成8.0～8.1 km/s。壳幔过渡带到那里去了?围绕这一问题,本文依据火山岩及其捕虏晶的研究,探讨了在软流圈底辟体上涌背景下,壳幔过渡带被破坏和改造的原因。最后从演化角度将辽西与张家口和西藏高原的壳-幔边界进行了比较。The Mesozoic crust-mantle interaction in west Liaoning province is studied according to petrologic and chronologic results of igneous rocks and xenoliths in them, and composition of the crust-mantle boundary in Mesozoic is reconstructed. Theoretically, there should be a developed crust-mantle transitional zone in Yixian-Beipiao area of west Liaoning province, where occurred active Mesozoic crust-manfle interaction. But the current Moho in the west Liaoning province is a clearly discontinuous interface with the seismic velocities above and below it being 6.5 - 6.7 km/s and 8.0 -8.1 km/s respectively. Where the crust-mantle transitional zone could have gone？ To answer this question, the authors explore the possible causes and processes of deformation and destruction of the crust- mantle transitional zone in the light of upwelling diapirs of asthenosphere. The crust-mantle-boundary structure in the west Liaoning province is also compared evolutionally with those in the Zhangjiakou area and in the Tibet plateau.

关 键 词：辽西 中生代 壳幔过渡带 底侵作用 捕虏晶 

分 类 号：P542.5[天文地球—构造地质学]