内蒙古额济纳旗雅干地区北山岩群的厘定及其地质意义  

Determination and Geological Significance of Beishan Group in Yagan Area,Ejiana,Inner Mongolia

作　　者：王振义 李钢柱 丁海生 于洋[4] 闫振军 黄磊[3] Wang Zhenyi;Li Gangzhu;Ding Haisheng;Yu Yang;Yan Zhenjun;Huang Lei(Hohhot Natural Resources Comprehensive Survey Center of China Geological Survey,Hohhot 010010,China;Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;Institute of Water Conservancy and Civil Engineering,Inner Mongolia Agricultural University,Hohhot 010018,China;Institute of Geological Survey,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质调查局呼和浩特自然资源综合调查中心,内蒙古呼和浩特010010 [2]中国地质科学院地质研究所,北京100037 [3]内蒙古农业大学水利与土木建筑工程学院,内蒙古呼和浩特010018 [4]中国地质大学地质调查研究院,湖北武汉430074

出　　处：《地球科学》2022年第4期1177-1193,共17页Earth Science

基　　金：中国地质调查局地质调查项目(No.DD2016007806);国家自然科学基金(No.51969023);内蒙古自治区科技计划项目(No.2020GG0076);内蒙古自然科学基金(No.2021MS04024)。

摘　　要：北山岩群是中亚造山带南缘中段明水-旱山地块的主要组成部分,研究其展布特征和形成时代对探讨带内地块前寒武纪基底构造演化、造山增生过程有着十分重要的意义.首次报道了在雅干南部少木尚德地区原划二叠系地层中新识别出的北山岩群的岩石组合、变质变形、剖面特征和碎屑锆石年龄特征,并将其与甘新蒙北山地区的北山岩群进行了对比.在其中的石英岩中运用LA-ICP-MS法获得了2个碎屑锆石年龄,其年龄值介于1075.7~2708.1 Ma,多集中在1100~1900 Ma,本区的北山岩群最大成岩年龄限定为1075.7 Ma.根据物源区时代特征对比,珠斯楞-杭乌拉构造带与北山地区微陆块、蒙古地块具有相近的亲缘性,与北山地区微陆块可能源于一个统一陆块.该发现证实了阿拉善北部地区与北山地区具有相同的前寒武纪褶皱基底,间接证明了雅干断裂带与红石山-百合山蛇绿构造混杂岩带在构造分化意义上可对比.Beishan Group is the main part of Mingshui-Hanshan block in the middle part of the southern margin of Central Asia orogenic belt,which is of great significance to the study of the tectonic evolution of Precambrian basement and the process of orogenic accretion.In this paper,it reports for the first time the rock association,metamorphic deformation,section characteristics and detrital zircon age of the Beishan Group in the original Permian strata in the Shaomushangde area,southern Yagan,and compares it with the Beishan Group in the Beishan area.Two detrital zircon ages were obtained by LA-ICP-MS in the quartzites.The ages range from 1075.7 to 2708.1 Ma,mostly from 1100 to 1900 Ma,and the maximum depositional age of Beishan Group in this area is 1075.7 Ma.The provenance analyses show tectonic affinity among microcontinent of the Beishan orogenic belts and Mongolia block,and may originate from a unified block with Beishan area.The discovery confirms that the northern Alxa area and Beishan area have the same Precambrian folded basement,and indirectly proves that the Yagan tectonic belt and HongshishanBaiheshan ophiolite tectonic melange belt are comparable in the sense of tectonic differentiation.

关 键 词：雅干南部 北山岩群 碎屑锆石 中新元古代 基底归属 构造 

分 类 号：P56[天文地球—构造地质学]