藏东类乌齐地区吉塘岩群的构造地层解析及主要依据  

Tectostratigraphical division of the Jitang rock group in the Leiwuqi Region of eastern Tibet,China and the main evidence

作　　者：邱军强[1,2] 强巴扎西 谢尧武 崔永泉 

机构地区：[1]安徽省地质调查院,安徽合肥230001 [2]西藏自治区地质矿产勘查开发局区域地质调查大队,西藏拉萨851400 [3]陕西省地质矿产勘查开发局区域地质矿产研究院,陕西咸阳712000

出　　处：《地质学刊》2015年第1期1-6,共6页Journal of Geology

基　　金：中国地质调查局项目"西藏 1:5万协通;类乌齐镇;瓦昌达;类乌齐县幅区域地质调查"( 1212010710211)

摘　　要：吉塘岩群沿藏东他念他翁—紫曲—吉塘一线分布,主要由片岩、片麻岩和糜棱岩组成构造岩片集合体,变形强烈,同位素年龄自古元古代—晚古生代,有必要进行解体。通过近年来的填图、测制剖面和同位素年龄的测定,并参考前人的资料及综合对比研究,对吉塘岩群（现藏东他念他翁变质杂岩体）进行了解体,将其分解为前奥陶纪—中三叠世类乌齐片麻岩套和前石炭纪吉塘岩群（〉340 Ma）2套地质体。然后将类乌齐片麻岩套划分为5个构造岩石地层单元：前奥陶纪查秋赛岩组（438.2±3.6）~700.0 Ma、早二叠世都拉扎片麻岩单元（282.1±0.91）Ma、晚二叠世加压玛片麻岩单元（254.0±8.0）Ma、早三叠纪世加隆片麻岩单元（246.3±0.8）Ma、中三叠世宁达片麻岩单元（227.0±0.6）Ma。吉塘岩群的解体是该区地层研究的重要进展,有助于藏东基础地质研究。The Jitang rock group along the Taniantaweng- Leiwuqi- Jitang area of eastern Tibet,is mainly composed of schist,gneiss and mylonite tectonic slices,and have been strongly deformed. Isotopic ages of this rock group range widely from the Paleoproterozoic to the late Paleozoic,and it is thus necessary to divide it in detail. In recent years,geological mapping,cross-section measurement and isotopic age determination have been conducted in this area. In combination with the previous data and comprehensive comparison,the original Jitang Rock Group（ the present Taniantaweng metamorphic complex in eastern Tibet） was divided into two sets of geological bodies,i. e.,the Pre-Ordovician- Middle Triassic Leiwuqi gneiss suite and the Pre-Carboniferous Jitang rock group. The Leiwuqi gneiss was further subdivided into five tectonic lithostratigraphic units,i. e.,the pre-Ordovician Chaqiusai rock group（ 438. 2 ± 3. 6）~ 700. 0 Ma,the early Permian Doulazha gneiss unit（ 282. 1 ± 0. 9） Ma,the late Permian Jiayama gneiss unit（ 254. 0 ± 8. 0） Ma,the early Triassic Jialong gneiss unit（ 246. 3 ± 0. 8） Ma,and the middle Triassic Ningda gneiss unit（ 227. 0 ± 0. 6） Ma. This detailed division of the original Jitang rock group is a major advance of the stratigraphical study in the area,and may contribute to the basic geological research in eastern Tibet.

关 键 词：吉塘岩群 解体 片麻岩单元 时代讨论 类乌齐地区 西藏东部 

分 类 号：P534[天文地球—古生物学与地层学]