扬子陆核古元古代变质事件——来自孔兹岩系变质锆石U-Pb同位素年龄的证据  

Paleoproterozoic metamorphic event in the nucleus of the Yangtze craton:Evidence from U-Pb geochronology of the metamorphic zircons from the khondalite

作　　者：邱啸飞[1,2] 赵小明[2] 杨红梅[1,2] 魏运许[1,2] 吴年文 卢山松[1,2] 江拓[1,2] 彭练红[2] QIU Xiaofei;ZHAO Xiaoming;YANG Hongmei;WEI Yunxu;WU Nianwen;LU Shansong;JANG Tuo;PENG Lianhong(Isotope Geochemistry Laboratory, Wuhan Center of Geological Survey, CGS, Wuhan 430205, Hubei, China;Research Center for Petrogenesis and Mineralization of Granitoid Rocks, CGS, Wuhan 430205, Hubei, China)

机构地区：[1]中国地质调查局武汉地质调查中心同位素地球化学研究室,湖北武汉430205 [2]中国地质调查局花岗岩成岩成矿地质研究中心,湖北武汉430205

出　　处：《地质通报》2017年第5期706-714,共9页Geological Bulletin of China

基　　金：国家自然科学基金项目<扬子克拉通神农架地区新元古代基性岩墙时代;成因和构造意义的地球化学研究>(批准号:41303026);中国地质调查局项目<武当-桐柏-大别成矿带武当-随枣地区岩浆岩同位素年代学与地球化学调查>(编号:DD20160030);<中南地区基础地质综合调查与片区总结>(编号:DD20160351)和中国地质调查局百名青年地质英才培养计划

摘　　要：崆岭杂岩除太古宙结晶基底外,还出露一套以含石墨和富铝矿物为特征的孔兹岩系。相对于结晶基底,目前对于该套表壳岩系的同位素年代学研究有限。对该套孔兹岩系中代表性岩石类型榴线英岩开展了变质锆石U-Pb同位素年龄测定。研究结果表明,榴线英岩变质年龄为1964±12Ma。结合前人在相近地层岩石组合中报道的锆石U-Pb年龄数据,推测崆岭杂岩孔兹岩系原岩可能沉积于2.1~2.0Ga。扬子陆核的古元古代变质-岩浆作用可能与全球广泛存在的同时期(2.1~1.8Ga)碰撞造山事件有关,暗示其很可能是Columbia超大陆的重要组成部分。Apart from the Archean metamorphic crystal basement,a series of khondalite-bearing graphites and Al-rich minerals areexposed in the Kongling Complex.However,relative to the study of metamorphic crystal basement,geochronological studies of thesupracrustal rocks are still very insufficient.In this study,the LA-ICP-MS zircon U-Pb study was carried out for the typical samplesof garnet-sillimanite quartzite in the khondalite series.The result shows that the garnet-sillimanite-quartzite was metamorphosed at1964±12Ma.Combined with the documented zircon U-Pb geochronologic data,the authors hold that the khondalite-series in theKongling Complex was deposited at2.1~2.0Ga.The Paleoproterozoic metamorphism and magmatism recognized in the interior ofthe Yangtze craton are consistent with the worldwide coeval collision-related orogenic event during2.1~1.8Ga,indicating that thisevent may have been an important component in the Columbia supercontinent.

关 键 词：扬子克拉通 崆岭杂岩 孔兹岩系 锆石U-PB 年代学 构造演化 

分 类 号：P534.3[天文地球—古生物学与地层学] P597.3[天文地球—地质学]