吉林辽源西保安群花岗质糜棱岩SHRIMPU-Pb定年  

SHRIMP U-Pb dating on granitic mylonite for Liaoyuan Xibaoan Group

作　　者：姜正龙[1] 彭玉鲸[2] 张为民[3] 梁爽[3] 曹元婷 

机构地区：[1]中国地质大学海洋学院,北京100083 [2]吉林省区域地质矿产调查所,长春130012 [3]中国石油勘探开发研究院,北京100083

出　　处：《岩石学报》2014年第6期1748-1756,共9页Acta Petrologica Sinica

基　　金：全国油气资源战略选区调查与评价专项(2009GYXQ02-06);国家自然科学基金项目(41130422)联合资助

摘　　要：吉林辽源西保安群是大面积花岗岩侵入体中的残留的构造岩片，传统认为属于华力西晚期或中休罗世花岗闪长岩-二长花岗岩系。本文通过对接触界线附近花岗质糜棱岩样品采集和锆石SHRIMPU—Pb定年，获得多组锆石年龄值为236~231Ma、267．6—358．6Ma、416．3±6．8Ma、9564-16Ma。认为该区花岗岩的侵入期次相当复杂，发育有早中三叠世岩体和发生了中、晚华力西期岩浆活动，西拉木伦河碰撞带可以东延至此，残留锆石的年龄与加里东期和Rodinia期拼合的构造岩浆活动相对应。Xibaoan Group in Jilin Province is a series of the tectonic slices residuesed in the granite intrusions, which is traditionally considered to be Late Variscan or Middle Jurassic granodiorite-monzonitic granite. In this study, samples of the granitic mylonite were collected along the contact line of Xibaoan Group in Dongfeng County Jilin Province, and the zircons were dated using the U-Pb method. The results indicate several zircon ages： 236 ~231Ma, 267.6 -358. 6Ma, 416. 3 ＋6. 8Ma, and 956 ＋ 16Ma. Based on the regional geology, we arrived at the following conclusions ： （ 1 ） The intrusive monzonitic granite of the Xibaoan Group in the contact zone experienced ductile shear deformation and formed in the Early-Middle Triassic. This event was an important part of the eastern extension of the collision belt of the Xar Moron River. （2） The zircon U-Pb SHRIMP age dates indicate that there were multiple periods of emplacement and multiple periods of development of residual magmatic zircons. The tectonic evolution of the Xibaoan Group was complex. （3） The U-Pb SHRIMP age dating of the residual zircons suggest that the magmatic activity occurred during the Caledonian and during the flattening of the Rodinia supercontinent.

关 键 词：花岗质糜棱岩 锆石U-PB年龄 西保安群 吉林辽源 

分 类 号：P588.121[天文地球—岩石学] P597.3[天文地球—地质学]