内蒙古呼和浩特北二道凹岩群黑云角闪片岩SHRIMP锆石U-Pb定年  

SHRIMP U-Pb Dating of Erdaowa Rock Group Biotite Hornblende Schist in the North Hohhot,Inner Mongolia

作　　者：张玉清[1] 张婷[2] 宝音乌力吉[1] 银海 曾庆荣 

机构地区：[1]内蒙古自治区岩浆活动成矿与找矿重点实验室内蒙古自治区地质调查院,呼和浩特010020 [2]中国农业大学信息与电气工程学院,北京100083 [3]内蒙古地质矿产勘查院,呼和浩特010010 [4]云南省地质调查院,云南玉溪653100

出　　处：《地质论评》2017年第5期1328-1336,共9页Geological Review

基　　金：中国地质调查局地质调查项目(编号:12120113013200;1212011120751)资助成果~~

摘　　要：二道凹岩群是20世纪70年代初1∶200000区域地质调查时在呼和浩特市北二道凹地区命名的,其岩石组合为变质砾岩、各种片岩、大理岩等。依据最新1∶250000区调成果,自下而上分了三个岩组,即红山口岩组、哈拉更沟岩组、东梁岩组。为进一步研究二道凹岩群的地质时代,本文对东梁岩组的黑云角闪片岩中锆石进行了高精度SHRIMP U-Pb测年研究,其时代为1890±8 Ma,认为该年龄值系黑云角闪片岩原岩的形成时代,即代表了二道凹岩群上部中基性火山岩的形成年龄,结合已有的年龄数据,进一步佐证了二道凹岩群形成于古元古代(1800~2400Ma)。Based on 1∶200000 regional geological mapping in the early 1970’s, the Erdaowa rock Group was named in Erdaowa area of north Hohhot, consisting of metamorphic conglomerate, schists and marbles and so on. According to the latest 1∶250000 regional survey results, the Erdaowa rock Group was subdivided into three sections from the bottom to top, including Hongshankou rock Formation, Halagenggou rock Formation and Dongliang rock Formation. In order to get new age constraint for the Erdaowa rock Group, SHRIMP U Pb dating of zircons from the biotite—amphibole schist of the Dongliang rock Formation was carried out by the authors of this paper. The data show the following age： 1890±8 Ma, interpreted as the formation age of biotite—amphibole schist, the intermediate—basic volcanics of the upper part of the the Erdaowa rock Group. Combined with the available age data, it is concluded that the Erdaowa rock Group formed in the Paleoproterozoic（1800~2400Ma）.

关 键 词：黑云角闪片岩 SHRIMP锆石U-PB年龄 二道凹岩群 内蒙古 

分 类 号：P588.344[天文地球—岩石学] P597.3[天文地球—地质学]