新疆西昆仑库尔良一带A型花岗岩的发现及地质意义  

Geochronology,Petrogeochemistry and Geological Significance of the Kuerliang Syenite in the Western Kunlun Mountains,Xinjiang

作　　者：李咸阳 滕宇翔 李正辉 郑飞 李兴俭 王哲 Li Xianyang;Teng Yuxiang;Li Zhenghui;Zheng Fei;Li Xingjian;Wang Zhe(Xinjiang Uygur Autonomous Region Institute of Geology,Urumqi,Xinjiang,830000,China;Xinjiang High Altitude Shallow Coverage Area Geological Exploration Engineering Technology Research Center,Urumqi,Xinjiang,830000,China;Xinjiang Zijin Gold Co.,Ltd,Wuqia,Xinjiang,845450,China)

机构地区：[1]新疆维吾尔自治区地质研究院,新疆乌鲁木齐830000 [2]新疆高海拔浅覆盖区地质勘察工程技术研究中心,新疆乌鲁木齐830000 [3]新疆紫金黄金有限公司,新疆乌恰845450

出　　处：《新疆地质》2025年第1期28-35,共8页Xinjiang Geology

基　　金：中央引导地方科技资金项目青藏高原北部西昆仑地区新生代火山活动与干热岩形成关系研究(ZYYD2023A12);新疆维吾尔自治区自然科学基金资助项目洋板块地层重建对卡拉麦里晚古生代洋盆俯冲削减的制约(2022D01A288);新疆地矿局自筹资金项目和田地区重要战略性矿产资源成矿规律研究与靶区优选(XGMB202249)共同资助。

摘　　要：西昆仑造山带是中国西部重要的地质构造单元之一,研究区位于西昆仑造山带之库地-其曼于特蛇绿混杂岩带内,北侧为铁克里克基底残块,南侧为奥伊切克-塔木其陆缘弧。本文对库尔良一带侵入岩开展了系统调查研究,获得正长岩的LA-ICP-MS锆石U-Pb年龄为(473±4.4)Ma(早奥陶世);岩石地球化学显示该岩体K_(2)O/Na_(2)O值较高,铝质指数(A/CNK)显示为铝-过铝质;稀土元素球粒陨石标准化配分模式表现为平缓的右倾型特征,具显著的负Eu异常,呈“海鸥型”型特征;微量元素显示Rb,K、La,Ce,Nd,Hf,Sm元素富集,Ba,Nb,Sr,Ti,P元素亏损。主量及微量元素特征显示A2型花岗岩地球化学特征;结合区域地质背景,认为该期花岗岩形成于原特提斯洋俯冲背景下巨厚地壳的重熔。The West Kunlun orogenic belt is one of the most important geological structural units in western China.The study area is within the Kudi-Qimanyuerte ophiolite mélange zone in the West Kunlun orogenic belt,with the Teklik basement fragment the north and the Oyik-Tamuch arc to the south.This paper presents a systematic investigation of the intrusive rocks in the Kuerliang area The LA-ICP-MS zircon U-Pb age of the syenite in these rocks is determined to be 473±4.4 Ma(Early Ordovician).The geochemistry of the rocks shows a high K_(2)O/Na_(2)O ratio,and the aluminum index(A/C)indicates an aluminum-rich to over-aluminum composition.The chondrite-normalized rare earth element(REE)distribution pattern shows a gentle rightward trend,a signi ficant negative Eu anomaly,forming a“seagull”pattern.The trace elements show enrichment in Rb,K,La,Ce,Nd,H,and Sm,and depletion in Ba,Nb,Sr,Ti,and P.The major and trace element characteristics exhibit the geochemical features of A2 granites.Combined with the regional geological background,it is inferred that these granites were formed by the remelting of thickened crust in the context of subduction of the Proto-Tethys Ocean.

关 键 词：新疆西昆仑 库尔良裂谷 U-PB测年 

分 类 号：P619.222[天文地球—矿床学]