南天山东段乌祖尔恩布拉格花岗岩锆石U-Pb年龄、地球化学特征及地质意义  

Zircon U-Pb age, geochemical characteristics, and geological significance of the Wuzur’ enbulage intrusion in the eastern section of South Tianshan Mountains

作　　者：刘传朋 邓俊 刘同 李兆营 梁成 姚永林 张勇 王凯凯 LIU Chuanpeng;DENG Jun;LIU Tong;LI Zhaoying;LIANG Cheng;YAO Yonglin;ZHANG Yong;WANG Kaikai(The 7th Institute of Geology&Mineral Exploration of Shangdong Province,Linyi,Shandong,276006;Shandong Key Laboratory of Diamond Mineralization Mechanism and Exploration,Linyi,Shandong,276006)

机构地区：[1]山东省第七地质矿产勘查院,山东临沂276006 [2]山东省金刚石成矿机理与探测重点实验室,山东临沂276006

出　　处：《地质论评》2022年第4期1481-1500,共20页Geological Review

基　　金：新疆地质勘查基金两权价款项目“新疆南天山东段大草湖一带1∶5万K45E014016 K45E014017、K45E015015、K45E015016、K45E015017五幅区域地质矿产调查”(编号:T15-1-LQ25)的成果。

摘　　要：乌祖尔恩布拉格花岗岩位于南天山造山带东段,其对于研究古生代南天山洋盆的闭合时限及南天山造山带构造演化具有重要意义。笔者等对南天山东段乌祖尔恩布拉格花岗岩进行了锆石U-Pb年代学、岩石地球化学研究。锆石U-Pb定年结果显示,2个样品的锆石U-Pb年龄为291.2±2.9 Ma和284.9±3.7 Ma,表明乌祖尔恩布拉格花岗岩形成于早二叠世。地球化学特征表明,乌祖尔恩布拉格花岗岩具有高硅,富含铝和碱,而钙、镁、铁、钛和磷含量低的特点,属于高钾钙碱性I型花岗岩;微量元素富集大离子亲石元素和轻稀土,亏损高场强元素(Nb、Ta、P、Ti),具有中等的负铕异常(δEu=0.27~0.87),且Sr、Ba也显示明显的亏损特征。乌祖尔恩布拉格花岗岩形成于后碰撞环境,表明至少在早二叠世,南天山洋盆东段已经闭合,南天山造山带在早二叠世由同碰撞构造环境向后碰撞构造环境演化。Objectives:The Wuzur’ enbulage intrusion is located in the eastern section of South Tianshan Orogenic Belt(STOB),which is of great significance for studying the closure time of the Paleozoic South Tianshan Ocean and the tectonic e volution of STOB.In this paper, we report new zircon U-Pb age and geochemical of the Wuzur’ enbulage intrusionin the eastern section of south Tianshan Mountains.Methods:On the basis of field investigation, according to the zircon U-Pb age, combined with geochemical characteristics.Results:The zircon U-Pb dating results show that the two ages of granite are 291.2 ± 2.9 Ma and 284.9±3.7 Ma, indicating that the Wuzur’ enbulage ion was formed in the Early Permian.They are characterized by high Si, rich in Al and alkali and low intrcontent usof Ca, Mg, Fe, Ti and P, belong to hi gh-potassium calc-alkaline I-typegran ite.They are enriched in LILEs and LREEs, depleted in HFSEs(e.g.,Nb, Ta, P, Ti), medium-negativeEu anomal ies(δEu = 0.27~0.87), and predominately negative Sr, Ba anomalies.Conclusions:The Wuzur’ enbulage intrusion was emplaced in a post-collisional environment, indicating that the eastern section of South Tianshan Ocean was closed at least in the Early Permian, and STOB evolved from syn-collisionaltectonic environment to post-collisional tectonic environment in the Early Permian.

关 键 词：南天山 花岗岩 锆石U-PB测年 地球化学 

分 类 号：P588.121[天文地球—岩石学] P597.3[天文地球—地质学] P542