阿尔金山地区构造单元划分和前寒武纪重要地质事件  

Tectonic units division and Precambrian significant geological events in Altyn Tagh Mountain, China

作　　者：刘永顺[1] 于海峰[1] 辛后田[1] 陆松年[1] 修群业[1,2] 李铨[1] 

机构地区：[1]中国地质调查局天津地质矿产研究所,天津300170 [2]核工业北京地质研究院,北京100029

出　　处：《地质通报》2009年第10期1430-1438,共9页Geological Bulletin of China

基　　金：中国地质调查局基础地质综合研究项目(编号:200113900070);国家自然科学基金重点项目(编号:40032010-C)资助

摘　　要：阿尔金山地区构造单元从北至南划分为敦煌地块、阿尔金北缘蛇绿混杂岩带、中阿尔金中—新元古代构造岩片、阿尔金构造杂岩带和阿尔金南缘基性超基性岩带5个构造单元,它们具有不同的岩石组合和变质变形特征。在正确识别地质事件的性质和特征的基础上,根据现有同位素年龄资料甄别出5期重要地质事件。3600～2500Ma的数据表明敦煌地块内存在始太古代、古太古代、中太古代、新太古代古老地壳和多期的岩浆活动;2500～1800Ma的古元古代是敦煌地块遭受强烈改造和中基性侵入岩形成的时代;1000～800Ma存在新元古代碰撞造山和大规模的岩浆活动;530～500Ma是阿尔金北缘蛇绿混杂岩带、高压变质泥质岩和榴辉岩的变质时代,形成的构造杂岩带是古生代早期秦岭-柴达木盆地北缘巨型碰撞带的西延部分;400Ma的柴水沟辉长岩的斜锆石年龄代表了碰撞后的裂解事件。Five tectonic units are divided in Altyn Tagh Mountain area respectively Dunhuang block, ophiolitic mélange of north Altyn Tagh, Meso-Neoproterozoic tectonic slice of middle Altyn Tagh, tectonic complex belt of Altyn Tagh and basic-ultrabasic igenous rocks zone of south Altyn Tagh with different rocks assemblages and deformation-metamorphism characteristics. Based on the correct recognition of tectonic significance of geological events, five important geological events are identified in this area according to the isotopic data. Data from 3600Ma to 2500Ma shows that within Dunhuang block there are Eoarchean, Paleaoarchean and mesoarchean crust relicts and multi-phase magmatic activities. In Palaeoproterozoic from 2500Ma to 1800Ma, strong deformation and metamorphic reworking took place in Dunhuang block with some medium-basic and granite intrusion. In the period from 1000Ma to 800Ma, a lot of syn-collisional granite bodies reflect Neoproterozoic collisional orogeny in the tectonic complex belt of Altyn Tagh. The events in the age from 530Ma to 500Ma include mélange accumulation and high pressure metamorphism of muddy rocks in the ophiolitic mélange of north Altyn Tagh, high pressure metamorphism of eclogites in the tectonic complex belt of Altyn Tagh, the tectonic complex belt of Altyn Tagh is the western part of the huge scale of collisional zone of Qinling-North margin of Qadam basin.

关 键 词：阿尔金山 构造单元 前寒武纪 地质事件 

分 类 号：P542.4[天文地球—构造地质学]