新疆阿尔泰克兰盆地泥盆纪花岗岩年代学特征及其地质意义  

Geochronological Characteristics of Devonian Granitoids in Kelan Basin of Altay, Xinjiang, China and Their Geological Implications

作　　者：张忠利 杨成栋[2] 张斌 王永强 李强[2] 杨富全[2] ZHANG Zhong-li;YANG Cheng-dong;ZHANG Bin;WANG Yong-qiang;LI Qiang;YANG Fu-quan(No. 706 Geological Team,Xinjiang Nonferrous Geoexploration Bureau,Altay 836500,Xinjiang,China;MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]新疆维吾尔自治区有色地质勘查局七〇六队,新疆阿勒泰836500 [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

出　　处：《地球科学与环境学报》2019年第4期414-430,共17页Journal of Earth Sciences and Environment

基　　金：新疆维吾尔自治区阿勒泰地区资源补偿奖励资金项目;国家自然科学基金项目(41802112)

摘　　要：新疆阿尔泰克兰盆地及外围广泛发育花岗质侵入岩。对分布于克兰盆地西南部和东北部的花岗岩开展了详细的岩相学及年代学研究,旨在为进一步研究克兰盆地的形成和演化机制提供新的依据。研究的花岗岩类有中细粒含二云正长花岗岩、中粗粒二云二长花岗岩、白云二长花岗岩和中粗粒英云闪长岩,LA-MC-ICP-MS锆石U-Pb年龄分别为(404.6±4.7)、(386.7±4.8)、(395.6±2.9)和(406.6±3.1)Ma,表明岩体侵位于早—中泥盆世。结合区域年代学和地质背景的研究成果认为,克兰盆地花岗岩形成时代有奥陶纪、泥盆纪和二叠纪,其中泥盆纪花岗岩的分布范围最大,泥盆纪特别是400Ma左右为克兰盆地花岗质岩浆侵入活动的高峰期,与区域上一致。克兰盆地泥盆纪花岗岩与康布铁堡组火山岩时代大体一致,花岗岩侵位略晚于火山岩,花岗岩与火山岩的时空关系表明两者为陆缘弧构造背景下同一岩浆事件的产物。Granitic intrusions are widespread in and around Kelan Basin of Altay, Xinjiang, China. With the aim to provide a new basis for further study on the origin and evolution of Kelan Basin, the detailed petrologic and geochronological constraints on the granitoids in the southwestern and northeastern segments of Kelan Basin were presented. Lithologies of the samples include medium-fine-grained two-mica-bearing syenogranite, medium-coarse-grained two-mica monzonite granite, muscovite monzonite granite, and medium-coarse-grained tonalite. The LA-MC-ICP-MS zircon U-Pb dating yields the ages of (404.6±4.7),(386.7±4.8),(395.6±2.9) and (406.6±3.1)Ma, respectively, indicating that the intrusion occurs in Early-Middle Devonian. Combined with the references of the regional geochronology and tectonic setting, the granitoids in Kelan Basin are thought to have been emplaced during Ordovician, Devonian and Permian. The Devonian granitoid has the largest distribution, especially the age of 400 Ma represents the peak intrusive phase of Kelan Basin, which is consistent with that of the entire Altay. The age of Devonian granitoid is slightly later than that of Kangbutiebao Formation in Kelan Basin. The temporal and spatial relationships between the granitoids and volcanic rocks indicate that they are the products of the same magmatic event in a continental arc setting.

关 键 词：年代学 花岗岩 锆石U-PB年龄 泥盆纪 岩浆侵入 克兰盆地 阿尔泰 新疆 

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