二连盆地吉尔嘎朗图凹陷南部基底花岗岩形成演化及其大地构造背景研究  

Emplacement and episodic denudation of basement granites from the southern Jiergalangtu Sag,Erlian Basin and its tectonic implications

作　　者：郭知鑫 杨永太 任祎 王正庆 冯志刚 陈亮 唐振平 GUO Zhixin;YANG Yongtai;REN Yi;WANG Zhengqing;FENG Zhigang;CHEN Liang;TANG Zhenping(School of Resource Environment and Safety Engineering,University of South China,Hengyang 421001,China;Hunan Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes,Hengyang 421001,China;Hengyang Key Laboratory of Geological Theory and Technology for the Nuclear Fuel Cycle,Hengyang 421001,China;CAS Key Laboratory of Crust-Mantle Materials and Environments,School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China)

机构地区：[1]南华大学资源环境与安全工程学院,湖南衡阳421001 [2]湖南省稀有金属矿产开发与废物地质处置技术重点实验室,湖南衡阳421001 [3]衡阳市核燃料循环地质理论与技术重点实验室,湖南衡阳421001 [4]中国科学技术大学地球和空间科学学院,中国科学院壳幔物质与环境重点实验,安徽合肥230026 [5]东华理工大学核资源与环境国家重点实验室,江西南昌330013

出　　处：《地学前缘》2023年第2期259-271,共13页Earth Science Frontiers

基　　金：南华大学博士启动基金资助项目(200XQD044);湖南省自然科学基金青年基金项目(2022JJ40370);湖南省教育厅科学研究项目一般项目(21C0274);2021年度衡阳市指导性计划项目(202121014463);国家自然科学基金项目(41372111);2019年度核资源与环境国家重点实验室开放基金资助项目(NRE1910);2022年湖南省研究生科研创新项目(CX20220978)。

摘　　要：二连盆地是中国北方重要的油气基地、煤炭基地和铀矿床富集区。基底花岗岩是盆地重要的含铀岩系沉积物源和铀源,以及重要的油气储层。然而,至今对二连盆地基底花岗岩的形成年代、成岩后剥蚀抬升历史及其与盆地构造演化关系的认识仍然比较薄弱。本文以吉尔嘎朗图凹陷南部地区钻井揭露的基底花岗岩为研究对象,通过锆石U-Pb年龄分析、锆石和磷灰石裂变径迹年龄分析,结合盆地地层和构造演化历史,对吉尔嘎朗图凹陷南部基底花岗岩的形成和演化进行了系统研究。研究结果表明,凹陷南部地区基底花岗岩成岩时代为早侏罗世(约175 Ma),成岩后经历了晚侏罗世((154±7) Ma、(146±7) Ma)和早白垩世中晚期((114±8) Ma)两期冷却事件。本文认为早侏罗世花岗岩的形成与蒙古—鄂霍茨克洋板块南向俯冲有关,成岩后的两期冷却事件记录了二连盆地经历的两期挤压构造作用,其中晚侏罗世冷却事件可能与蒙古—鄂霍茨克洋的关闭有关,早白垩世中晚期的冷却事件可能与亚洲大陆东缘发生的陆-陆碰撞事件有关。The Erlian Basin is one of the most important oil, gas, coal, and uranium-bearing basins in northern China, and basement granites of the Erlian Basin are gaining importance as uranium source and petroleum reservoir. However, the emplacement time and denudation history of the basement granites are poorly studied. Here, based on newly obtained zircon U-Pb geochronological data and zircon/apatite fission track evidence, the diagenetic age and uplift history of basement granites of the southern Jiergalangtu Sag, Erlian Basin are analyzed. The diagenetic age is constrained to the Early Jurassic(ca. 175 Ma), and two cooling events are recognized. The two cooling events are refined to the Late Jurassic(ca. 154 Ma and ca. 146 Ma) and late Early Cretaceous(ca. 114 Ma), respectively, and considered to be related to the contractional deformation in the Erlian Basin. The present study tentatively attributes the formation of basement granites to the southward subduction of the Mongol-Okhotsk Ocean Block, Late Jurassic cooling to the closure of the eastern Mongol-Okhotsk Ocean, and late Early Cretaceous cooling to the collision of micro-block with East Asia.

关 键 词：二连盆地 吉尔嘎朗图凹陷 基底花岗岩 U-PB年龄 裂变径迹 

分 类 号：P541[天文地球—构造地质学] P597.3[天文地球—地质学]