吉林省南部二道白河地区中元古代地层的发现及其地质意义  

Discovery and Geological Significance of Mesoproterozoic Strata in Erdaobaihe Area, Southern Jilin Province

作　　者：石成龙 周晓东[2] 聂立军[2] 周凯[2] 孙罡[2] Shi Chenglong;Zhou Xiaodong;Nie Lijun;Zhou Kai;Sun Gang(Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;Survey of Regional Geological and Mineral Resource of Jilin Province,Changchun 130022,China)

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]吉林省区域地质矿产调查所,吉林长春130022

出　　处：《地球科学》2020年第7期2441-2451,共11页Earth Science

基　　金：全国陆域及海区地质图件更新与共享(No.DD20190370)。

摘　　要：为了查明吉林南部是否存在中元古代地层,并探索该地区的构造演化过程,利用LA-MC-ICP-MS方法对该区碎屑岩样品进行U-Pb同位素定年以及原位Lu-Hf同位素测试.两件碎屑锆石年龄主要集中在太古代(>2.5 Ga),εHf(t)为正值(+1.5^+7.5和+1.4^+4.6),中元古代和古元古代(1.7~2.3 Ga),εHf(t)为(-5.6^+5.7和-5.4^+3.4).表明其物质来源主要为太古代结晶基底和古元古代晚期辽东-吉南造山带同碰撞的花岗岩,少量可能来源于造山带的火山岩及早期花岗岩.该套地层可能为龙岗、狼林两个微陆块经历俯冲-碰撞形成了胶-辽-吉造山/活动带后的中元古代盖层沉积.In order to find out whether Mesoproterozoic strata exist in southern Jilin,and to explore the tectonic evolution of this area.U-Pb isotope dating and in situ Lu-Hf isotope test were performed on the detrital zircon samples in this area by LA-MC-ICPMS.The age of detrital zircon is mainly concentrated in Archean(>2.5 Ga),εHf(t)values show positive(+1.5 to+7.5 and+1.4 to+4.6),Mesoproterozoic and Paleoproterozoic(1.7~2.3 Ga),andεHf(t)values appear positive and negative(-5.6 to+5.7 and-5.4 to+3.4).It is indicated that the material source are mainly the granites of the Archean and the Late Paleoproterozoic Liaodong-Jinan orogenic belt,and a small amount may be derived from the volcanic rocks and early granites of the orogenic belt.The set of strata may be the Middle Proterozoic caprock deposits after the subduction-collision of the two microcontinental blocks of Longgang and Langlin formed the Jiao-Liao-Ji orogenic/active belt.

关 键 词：吉林南部 二道白河 年代学 沉积地层 碎屑锆石 

分 类 号：P611[天文地球—矿床学]