西昆仑苏纳克早古生代花岗岩锆石U-Pb年龄、地球化学特征及其地质意义  

Zircon U-Pb Dating and Geochemical Characteristics of Early Paleozoic Granite in the Southern Sunake of West Kunlun,Northwest China and Their Geological Significances

作　　者：陈贵民 刘俊辰 王义天[2] 胡乔青[2] 黄诗康 孙政浩 尼加提·阿布都逊 孔德懿 刘景峰 CHEN Gui-min;LIU Jun-chen;WANG Yi-tian;HU Qiao-qing;HUANG Shi-kang;SUN Zheng-hao;Nijiati ABUDUXUN;KONG De-yi;LIU Jing-feng(No.6 Geological Party,Xinjiang Bureau of Geology and Mineral Exploration and Development,Hami 839000,Xinjiang,China;MLR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;School of Geology and Mining Engineering,Xinjiang University,Urumqi 830046,Xinjiang,China;No.10 Geological Party,Xinjiang Bureau of Geology and Mineral Exploration and Development,Hotan 848000,Xinjiang,China)

机构地区：[1]新疆维吾尔自治区地质矿产勘查开发局第六地质大队,新疆哈密839000 [2]中国地质科学院矿产资源研究所自然资源部成矿作用与资源评价重点实验室,北京100037 [3]中国地质大学(北京)地球科学与资源学院,北京100083 [4]新疆大学地质与矿业工程学院,新疆乌鲁木齐830046 [5]新疆维吾尔自治区地质矿产勘查开发局第十地质大队,新疆和田848000

出　　处：《地球科学与环境学报》2020年第4期427-441,共15页Journal of Earth Sciences and Environment

基　　金：“十二五”国家科技支撑计划项目(2015BAB05B02)。

摘　　要：苏纳克花岗岩位于西昆仑造山带库尔良裂谷带内,岩体岩性为黑云母二长花岗岩,其中侵入有花岗闪长岩脉。LA-ICP-MS锆石U-Pb定年结果显示,黑云母二长花岗岩和花岗闪长岩脉的结晶年龄分别为(477.0±2.1)Ma和(466.7±2.0)Ma,为早—中奥陶世岩浆活动的产物。苏纳克黑云母二长花岗岩主量元素组成具有高硅(SiO2含量(质量分数,下同)为72.75%~76.44%)、富碱(Na2O+K2O值为8.58%~9.12%)的特征,A/CNK值为1.02~1.11,为弱过铝质、高钾钙碱性系列。球粒陨石标准化稀土元素配分模式表现为平缓的右倾型特征,并呈“V”字型,且具有显著的负Eu异常。微量元素组成明显富集Rb、K等大离子亲石元素及Th、U等高场强元素,强烈亏损Ba、Sr、Eu、P、Ti等。整体上,苏纳克黑云母二长花岗岩具有高分异I型花岗岩的地球化学特征,是西昆仑早古生代原特提斯洋俯冲过程中的产物。Sunake granite,located in Kuerliang rift zone of West Kunlun orogen,is composed of biotite monzogranite,in which granodiorite dikes are intruded.The LA-ICP-MS dating yields zircon U-Pb ages of(477.0±2.1)Ma and(466.7±2.0)Ma from the biotite monzogranite and granodiorite,respectively,which are the products of tectonic magmatism during Early-Middle Ordovician.The major elements of Sunake biotite monzogranite are characterized by high silica(the contents of SiO 2 are 72.75%-76.44%)and alkali(the contents of Na 2O+K 2O are 8.58%-9.12%)with the A/CNK of 1.02-1.11,showing that they are weakly peraluminous and high-K calc-alkaline series.The chondrite-normalized REE pattern presents a gentle right-leaning and“V”shape with significant negative Eu anomalies.The trace elements are enriched in Rb,K,Th and U,and evidently depleted in Ba,Sr,Eu,P and Ti.Overall,Sunake biotite monzogranite has the geochemical characteristics of high fractionated I-type granite,which is the product of Proto-Tethys Ocean subduction in West Kunlun during Early Paleozoic.

关 键 词：花岗岩 锆石U-PB年龄 地球化学 岩石成因 构造背景 库尔良裂谷带 西昆仑 新疆 

分 类 号：P588.1[天文地球—岩石学] P59[天文地球—地质学]