兴蒙造山带新发现构造混杂岩的地质意义探讨  

Tectonic significance of the newly discovered tectonic mélange within the Xingmeng orogenic belt

作　　者：王果胜[1] 李红英 周志广[1] 吴晨 Wang Guosheng;Li Hongying;Zhou Zhiguang;Wu Chen(School of Earth Sciences and Resources,China University of Geosciences Beijing,Beijing 100083;School of Economics,Sichuan University of Science&Engineering,Zigong,Sichuan 643002;Key laboratory of Continental Collision and Plateau Uplift,Institute of Tibetan Plateau Research,and Center for Excellence in Tibetan Plateau Earth Sciences,Chinese Academy of Sciences,Beijing 100101)

机构地区：[1]中国地质大学(北京),地球科学与资源学院,北京100083 [2]四川轻化工大学,经济学院,四川自贡643002 [3]中国科学院青藏高原研究所,大陆碰撞与高原隆升实验室,北京100101

出　　处：《地质科学》2021年第2期483-507,共25页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目(编号:41872232)资助。

摘　　要：兴蒙造山带发育多条蛇绿混杂岩带,为研究古亚洲洋闭合及造山带形成与演化提供了珍贵的地质资料,由于各蛇绿混杂岩带的板块构造意义以及晚石炭—早二叠世的大地构造属性至今仍未达成共识,导致兴蒙造山带晚古生代的板块构造格局存在争议。笔者近年来新发现了近东西向展布的卫境、补力太、准木布台和大石寨构造混杂岩,它们与晚石炭世—早二叠世海相沉积—火山地层及苏左旗—西乌旗岩浆岩带具有近一致的空间展布特征。本次研究主要通过构造混杂岩中玄武安山岩、辉长岩岩块和闪长岩的年龄,初步限定混杂岩带的时代为晚石炭世—早二叠世,应代表了新生洋盆闭合的产物,并初步探讨其与索伦山—满都拉、温都尔庙—图林凯、柯单山—小苇塘、达青牧场—迪彦庙和二连—贺根山蛇绿混杂岩的时空关系,为研究兴蒙造山带板块构造演化及晚石炭世—早二叠世的构造属性提供新的约束,进而对古亚洲洋闭合模式和陆壳增生机制提供研究支撑。There are several ophiolitic mélange zones developed in the Xingmeng orogenic belt,which has the fundamental implication for the closure of the Paleo-Asian Ocean,and the evolution and formation process of the orogen.Despite this importance,no consensus has been reached on the issues of the plate tectonic framework and evolution of these ophiolitic mélange zones,and the tectonic attribute during the Late Carboniferous-Early Permian,as a result that there is still debate on the plate tectonic pattern of Xingmeng orogenic belt in the Late Paleozoic.In recent years,we have newly found the E-W extending Weijing,Bulitai,Zhunmubutai,and Dashizhai tectonic mélanges,which are characterized by similar distribution as the Late Carboniferous-Early Permian marine sedimentary-volcanic strata and Suzuoqi-Xiwuqi magmatic belt.We constrain the age of the tectonic mélange belt as the Late Carboniferous-Early Permian together with the basaltic andesite and gabbro blocks and the diorite intrusion,which should be the production of the closure of the nascent ocean.Moreover,we will further discuss the spatial-temporal relationships between Solonker-Xar Moron,Wenduermiao-Tulinkai,Kedanshan-Xiaoweitang,Daqingmuchang-Diyanmiao,and Erlian-Hegenshan ophiolitic mélanges.These works will provide better constraints on the plate tectonic evolution of the Xingmeng orogenic belt and its tectonic attribute during the Late Carboniferous-Early Permian,then will further help to give new research supports for the closure process of the Paleo-Asian Ocean and the mechanism of continental crust accretion.

关 键 词：构造混杂岩 兴蒙造山带 中亚造山带 古亚洲洋 构造环境 

分 类 号：P597[天文地球—地球化学] P542[天文地球—地质学]