阿尔金—祁连—昆仑造山带早古生代构造格架及结晶岩年代学研究进展  

Progress of Studies on Early Paleozoic Tectonic Framework and Crystalline Rock Geochronology in Altun—Qilian—Kunlun Orogen

作　　者：董顺利[1,2] 李忠[1] 高剑[1,2] 朱炼[3] 

机构地区：[1]中国科学院地质与地球物理研究所岩石圈演化国家重点实验室,北京100029 [2]中国科学院大学,北京100049 [3]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地质论评》2013年第4期731-746,共16页Geological Review

基　　金：国家自然科学基金项目(批准号:41172096);国家重大专项(编号:2011ZX05008-003)的成果

摘　　要：阿尔金—祁连—昆仑(阿祁昆)造山带早古生代加里东期的构造事件一直是国内外研究的热点,近年来发表了大量的研究成果。本文着重调研了各造山带内构造混杂带的重要组成部分——蛇绿岩、岩浆岩和高压—超高压变质岩的地球化学特征,尤其是同位素年代学资料。蛇绿岩的地球化学特征表明阿尔金—祁连—昆仑地区早古生代的蛇绿岩有MORB和OIB两种类型,其产出于成熟的洋盆、小洋盆或是与消减带有关的弧前或弧后盆地,还有很大的争议。根据大量的同位素年代学资料,阿尔金—祁连—昆仑地区洋盆在晚新元古代开启,寒武纪发育成熟,于中—晚奥陶世开始发生俯冲消减作用,晚志留世—早泥盆世进入碰撞后伸展阶段。再者,通过同位素年代学数据对比,证明北阿尔金与北祁连、南阿尔金与柴达木北缘、西昆仑与东昆仑在早古生代分别为同一条构造带,于新生代期间被活动的阿尔金左行走滑断裂错开了400多千米。The Early Paleozoic—Caledonian tectonic event of Altun—Qilian—Kunlun orogen has been always the research hotspot at home and abroad. Plenty of research results were published in these years. This paper mainly investigated the geochemical characteristics of the important components of the tectonic melange zones, such as the ophiolites, magmatic rocks and HP—UHP metamorphic rocks, especially the results of the isotopic geochronology. The geochemical characteristics show that the ophiolites have two types, MORB and OIB, whether the ophiolites developed in the mature ocean, small ocean basin, or fore-arc/back-arc basin remains controversial today. According to plenty of isotopic geochronological data, the Proto-Tethys in Altun—Qilian—Kunlun area developed into mature-ocean stage in Cambrian, started to subduct in Middle—Late Ordovician, and became to the post-collision and extension environment in Late Silurian Epoch—Early Devonian Epoch. Furthermore, the North Altun and the North Qilian, the South Altun and the North Qaidam, the West Kunlun and the East Kunlun were the same tectonic belt in Early Paleozoic, respectively, which were fractured by the Cenozoic Altun Tagh strike- slip falut.

关 键 词：阿尔金山 祁连山 昆仑山 造山带 早古生代 蛇绿岩 年代学 

分 类 号：P597.3[天文地球—地球化学]