Origin of Early Creceouscalc-alkaline granite, Taxkorgan: Implications for evolution of Tethys evolution in central Pamir  

塔什库尔干早白垩世钙碱性花岗岩成因：对中帕米尔特提斯洋演化的启示（英文）

作　　者：LI Rui-hua PENG Bo ZHAO Cai-sheng YU Miao SONG Lin-shan ZHANG Han 李睿华;彭勃;赵财胜;于淼;宋林山;张晗(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,CAGS,Beijing 100037,China;School of Earth and Space Sciences,Peking University,Beijing 100871,China;Technology and International Cooperation Division,Ministry of Nature Resources of China(MLR),Beijing 100034,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,School of Geosciences and Info-Physics,Central South University,Changsha 410083,China;Geological Research Academy of Xinjiang,Urumqi 830011,China;Yanduzhongshi Geological Analysis Laboratories Ltd.,Beijing 100094,China)

机构地区：[1]MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,CAGS,Beijing 100037,China [2]School of Earth and Space Sciences,Peking University,Beijing 100871,China [3]Technology and International Cooperation Division,Ministry of Nature Resources of China(MLR),Beijing 100034,China [4]Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,School of Geosciences and Info-Physics,Central South University,Changsha 410083,China [5]Geological Research Academy of Xinjiang,Urumqi 830011,China [6]Yanduzhongshi Geological Analysis Laboratories Ltd.,Beijing 100094,China

出　　处：《Journal of Central South University》2019年第12期3470-3487,共18页中南大学学报（英文版）

基　　金：Project(41802103)supported by the National Natural Science Foundation of China;Project(2017YFC0601403)supported by the National Key R&D Program of China

摘　　要：The Pamir plateau may have been a westward continuation of Tibet plateau.Meanwhile,the Rushan-Pshart suture is correlative to the Bangong-Nujiang suture of Tibet,and the Central Pamir is the lateral equivalent of the Qiangtang Block.We present the first detailed LA-ICPMS zircon U-Pb chronology,major and trace element,and Lu-Hf isotope geochemistry of Taxkorgan two-mica monzogranite to illuminate the Tethys evolution in central Pamir.LA-ICPMS zircon U-Pb dating shows that two-mica monzogranite is emplaced in the Cretaceous(118 Ma).Its geochemical features are similar to S-type granite,with enrichment in LREEs and negative Ba,Sr,Zr and Ti anomalies.All the samples show negative zirconεHf(t)values ranging from 17.0 to 12.5(mean 14.5),corresponding to crustal Hf model(TDM2)ages of 1906 to 2169 Ma.It is inferred that these granitoids are derived from partial melting of peliticmetasedimentary rocks analogous to the Paleoproterozoic Bulunkuole Group,predominantly with muscovite schists component.Based on the petrological and geochemical data presented above,together with the regional geology,this work provides new insights that Bangong Nujiang Ocean closed in Early Cretaceous(120114 Ma).帕米尔高原作为青藏高原的西延,Rushan-Pshart缝合带对应青藏高原的班公湖-怒江缝合带,中帕米尔地块即为羌塘板块的西向延伸部分。本文对塔什库尔干二云母二长花岗岩进行了详细的LA-ICPMS锆石U-Pb年代学,岩石地球化学和Lu-Hf同位素分析,阐明了中帕米尔构造结的特提斯演化。LA-ICPMS锆石U-Pb定年结果显示,二云母二长花岗岩形成于早白垩世(118 Ma)。地球化学特征与S型花岗岩相似,富集LREEs,亏损Ba,Sr,Zr,Ti。锆石样品全部显示负的εHf(t),范围介于17.0~12.5(平均值14.5),对应的二阶段模式年龄(TDM2)为1906~2169 Ma。上述地球化学特征表明该花岗岩形成于部分熔融的古元古代布伦阔勒群泥质变质碎屑岩,主要由白云母片岩组成。鉴于上述岩石成因与地球化学数据,综合区域地质,本文进一步限定了中帕米尔地区班公湖-怒江洋闭合时代为早白垩世(120~114 Ma)。

关 键 词：Tethys ocean Pamir plateau S-type granite Early Cretaceous tectono-magmatism Geochronology and petrogenesis 

分 类 号：P58[天文地球—岩石学]