西准噶尔拉巴岩体的成因--来自岩石学、年代学和地球化学的证据  

Petrogenesis of Laba Plutons in West Junggar,Central Asian Orogenic Belt:Evidence from Petrology,Chronology,and Geochemistry

作　　者：徐盛林[1] 陈宣华[1] 马飞宙[2] 邵兆刚[1] 丁伟翠[1] 韩乐乐 王叶 XU Sheng-lin;CHEN Xuan-hua;MA Fei-zhou;SHAO Zhao-gang;DING Wei-cui;HAN Le-le;WANG Ye(Chinese Academy of Geological Sciences,Beijing 100037;China Geological Survey,Beijing 100037;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083)

机构地区：[1]中国地质科学院,北京100037 [2]中国地质调查局,北京100037 [3]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地球学报》2022年第6期875-894,共20页Acta Geoscientica Sinica

基　　金：中国地质调查局地质调查项目(编号:DD20160083;DD20190011;DD20221643);国家重点研发计划项目(编号:2018YFC0603700);中国地质科学院基本科研业务费项目(编号:JKY202011)联合资助。

摘　　要：西准噶尔西南部的拉巴岩体形成于早二叠世(285.7~295.1 Ma),由花岗岩、花岗闪长岩、二长花岗岩岩基和一系列花岗闪长斑岩、闪长岩、花岗岩等岩脉组成,矿物主要包括石英、斜长石、碱性长石、角闪石和黑云母等,CaO、Na_(2)O含量较高,Eu弱负异常,高εNd、低(^(87)Sr/^(86)Sr)i,具有中高硅、钙碱性、贫镁铁、准铝质-弱过铝质的特点,属典型的Ⅰ型花岗岩,可进一步分为高Sr低Yb的高压型埃达克岩和低Sr高Yb的低压型岛弧花岗岩,均形成于洋壳俯冲的岛弧环境,西准噶尔地区在早二叠世可能仍存在未完全关闭的有限洋盆,对完善区域大地构造演化具有重要意义。The Laba plutons in southwest West Junggar were formed in the Early Permian(285.7~295.1 Ma).They are composed of granite,granodiorite,monzogranite batholith,and a series of granodiorite porphyry,diorite,granite,and other dikes.Minerals mainly consist of quartz,plagioclase,alkali feldspar,hornblende,and biotite.The Laba plutons are characterized by medium-high silicon,calc-alkaline,mafic,and peraluminous with high CaO and Na_(2)O content,Eu weak negative anomaly,highεNd,and low(^(87)Sr/^(86)Sr)i.They are typical Ⅰ-Type granites formed in the island arc environment of oceanic crust subduction,which can be further divided into high-pressure adakite with high Sr and low Yb content and low-pressure island arc granite with low Sr and high Yb content.In the Early Permian,there may still have been a limited ocean basin in West Junggar,which is of great significance to improvement of the regional tectonic evolution.

关 键 词：地球化学 U-PB年代学 SR-ND-HF同位素 有限洋盆 西准噶尔 

分 类 号：P584[天文地球—岩石学] P597.3[天文地球—地质学]