西昆仑造山带东段中生代碰撞造山事件的记录:来自新疆温泉—胜利达坂一带三叠纪侵入岩年代学、地球化学的证据  

Record of Mesozoic Collision Orogeny on the Eastern Section of the West Kunlun Orogen:Evidence from Geochronology and Geochemistry of the Triassic Wenquan-Shenglidaban Granitic Intrusions,Xinjiang

作　　者：鲁浩 刘欢 胡峰 王海波 王超 孔祥超 LU Hao;LIU Huan;HU Feng;WANG Haibo;WANG Chao;KONG Xiangchao(Shandong No.3 Exploration Institute of Geology and Mineral Resources,Yantai,Shandong 264004,China)

机构地区：[1]山东省第三地质矿产勘查院,山东烟台264004

出　　处：《现代地质》2023年第3期573-585,共13页Geoscience

基　　金：新疆地勘基金中心项目“新疆西昆仑温泉—独尖山一带1:5万区域地质矿产调查”(K15-1-LQ20);“新疆若羌县大沙沟一带1:5万区域地质矿产调查”(XB-DK-2015-1-05)。

摘　　要：西昆仑造山带东段温泉—胜利达坂一带发育大量三叠纪侵入岩,岩性主要为中细粒二长花岗岩,为进一步丰富西昆仑造山带中生代地质构造演化史,对区内金、汞、锑等多金属的成矿时代提供年代学制约,对研究区内三叠纪阿塔木帕下序列花岗岩进行了详细的岩石学、岩石地球化学和锆石U-Pb年代学研究。研究结果表明,温泉—胜利达坂一带花岗岩形成时代为(203.3±1.4)Ma,为晚三叠世岩浆活动产物;岩石地球化学特征显示,区内花岗岩SiO_(2)含量为74.41%~76.78%,Na_(2)O为2.70%~3.81%,K_(2)O为3.93%~5.01%,铝饱和指数(A/CNK)为1.00~1.25,表明区内花岗岩属过铝质高钾钙碱性系列花岗岩;岩石稀土元素总量较低,且富集轻稀土元素,具负Eu异常(δEu=0.39),相对富集Rb、Th、U,亏损Ba、Nb、Sr、Ti等元素,显示岩石具有壳源花岗岩特征,为S型花岗岩。结合区域构造演化,区内三叠纪阿塔木帕下序列花岗岩形成于造山作用后造山阶段,为地壳变质碎屑岩俯冲到下地壳部分熔融后形成岩浆,上升侵位形成的后碰撞型花岗岩。Many Triassic intrusive rocks are emplaced in Wenquan-Shenglidaban area in the eastern section of the West Kunlun orogen.The lithology mainly includes medium-/fine-grained monzogranite,which records the Mesozoic tectonic evolution of the orogen and provides chronological constraints for the metallogenic age of gold,mercury,antimony and other metals in this area.In this study,detailed analyses on the petrology,whole-rock chemistry and zircon U-Pb geochronology of the Lower Triassic Adamupa lower series granites are presented.The results show that the Wenquan-Shenglidaban granite was emplaced at(203.3±1.4)Ma,indicating a product of the Late Triassic magmatic activity.The rocks have SiO_(2),Na_(2)O,K_(2)O and A/CNK of 74.41%-76.78%,2.70%-3.81%,3.93%-5.01%and 1.00-1.25,respectively,indicating that the granites are peraluminous high-K calc-alkaline with low total rare earth element contents.The granites are rich in light rare earth elements and negative Eu anomaly(δEu=0.39),and are relatively rich in Rb,Th and U,but depleted in Ba,Nb,Sr,and Ti.This indicates that the granites are crustal-derived S-type.Combined with the regional tectonic evolution,the Atamupa granite was likely formed in the post-orogenic stage.It is probably a post-collisional granite sourced by the partial melting of the subducted metamorphic clastic rocks into the lower crust.The resulted magma then ascended and emplaced at upper crust and the granites was formed.

关 键 词：S型花岗岩 锆石U-PB年代学 岩石地球化学 温泉—胜利达坂 西昆仑 

分 类 号：P588.12[天文地球—岩石学] P595[天文地球—地质学] P597.3