额尔齐斯杂岩碎屑锆石U-Pb年龄及其对阿尔泰和东准噶尔地体拼合时限的制约  

Detrital zircon U-Pb ages from the Irtysh complex and its constraints on the amalgamation time of Altai and East Junggar terranes

作　　者：李昂 徐严[1] 韩宝福[1] 廖闻[1] LI Ang;XU Yan;HAN Baofu;LIAO Wen(Ministry of Education Key Laboratory of Orogenic Belts and Crustal Evolution,School of Earth and Space Sciences,Peking University,Beijing 100871,China)

机构地区：[1]造山带与地壳演化教育部重点实验室,北京大学地球与空间科学学院,北京100871

出　　处：《地质通报》2024年第6期1032-1046,共15页Geological Bulletin of China

基　　金：国家自然科学基金项目《古亚洲洋南部俯冲起始的三重约束》(批准号:41972234)。

摘　　要：额尔齐斯杂岩位于新疆北部的阿尔泰和东准噶尔地体之间,经历了强烈的变质变形作用,记录了2个地体的构造拼合事件。为约束阿尔泰和东准噶尔地体的拼合时限,通过碎屑锆石U-Pb年龄分析探讨沉积物源。从变碎屑岩样品中获得最年轻的碎屑锆石年龄为354 Ma。在综合分析新的和已发表的碎屑锆石和区域构造年代学资料后,认为在额尔齐斯杂岩中,除同时以阿尔泰和东准噶尔地体为物源和以东准噶尔地体为单一物源的2类晚石炭世同碰撞沉积外,还可能包括较早以阿尔泰地体为单一物源的被动陆缘沉积,表明额尔齐斯杂岩形成时,阿尔泰和东准噶尔地体已经拼合。The Irtysh complex is located between Altai and East Junggar terranes in Northern Xinjiang and underwent strong metamorphism and deformation,which recorded the tectonic amalgamation of the two terrains.In order to constrain the amalgamation time of the Altai and East Junggar terrains,we used detrital zircon U-Pb ages to analyze and discuss the provenance.The youngest detrital zircon age obtained from the metaclastic rock sample is 354 Ma.Based on a comprehensive analysis of new and published detrital zircon U-Pb age data from the Irtysh complex and a comparison with regional tectonic and magmatic U-Pb age data,this paper proposes that the Irtysh complex may contain older detritus from the passive continental margin of the Altai terrane,in addition to the Late Carboniferous syn-collisional deposits from both of the Altai and East Junggar terranes and only the East Junggar terrane,suggesting that the Altai and East Junggar terranes had been amalgamated when the Irtysh complex was formed.

关 键 词：额尔齐斯杂岩 变碎屑岩 物源分析 碎屑锆石 

分 类 号：P597.3[天文地球—地球化学]