秦岭造山带古生代岩浆作用及地球动力学意义  

Paleozoic Magmatism in the Qinling Orogen and Its Geodynamic Significance

作　　者：吴元保[1] Wu Yuanbao(School of Earth Sciences,China University of Geosciences,Wuhan 430074,CAzwa)

机构地区：[1]中国地质大学地球科学学院

出　　处：《地球科学》2019年第12期4173-4177,共5页Earth Science

基　　金：国家“973”计划项目(No.2015CB856106)

摘　　要：秦岭造山带记录了华南华北板块聚合的完整过程.古生代岩浆岩记录了造山过程中的壳幔相互作用和造山带演化的动力学过程.古生代的中基性岩浆岩揭示了俯冲隧道内变质脱水交代岩石圈地幔过程,其中富水基性杂岩为富钾基性岩,地球化学特征显示其地幔源区经历了洋壳沉积物的交代;看丰沟岩体为高镁闪长岩,地球化学特征显示其来自经历俯冲流体交代的地幔源区.通过对古生代岩浆岩的研究发现,其具有明显的时空分布规律,它们对应于原特提斯洋俯冲、后撤、前进和回转等过程.所以壳幔相互作用发生在原特提斯洋俯冲过程中.The Qinling orogen records the whole amalgamation of the North China and South China blocks.The Paleozoic magmatism in the Qinling orogen registers crust-mantle interaction and geodynamics of the orogeny.In this paper,we give a brief review of the Paleozoic magmatism.Intermediate-mafic magmatic rocks derived from the metasomatic mantle reveal fluid activities in the subducted channel.The Fushui mafic complex is enriched in K,and its mantle source has been metasomatized by subducted oceanic sediment.The Kanfenggou pluton belongs to high-Mg diorite.It is inferred by the geochemical characteristics that the mantle sources of the Kanfenggou pluton have experienced subducted fluid metasomatism.The results show that they exhibit a clear spatio-temporal variation,which might be caused by the subduction,retreat,advancement,and rollback of the Proto-Tethys oceanic plate.Therefore we suggest that the Paleozoic crust-mantle interaction was induced by the subduction of the Proto-Tethys ocean.

关 键 词：秦岭造山带 古生代 岩浆作用 地球动力学. 

分 类 号：P581[天文地球—岩石学]