西天山特克斯地区哈拉达拉基性岩体LA-ICP-MS锆石U-Pb定年及其地质意义  

LA-ICP-MS Zircon U-Pb Dating of the Haladala Basic Pluton in Tekesi County,Western Tianshan and Its Geological Implication

作　　者：陈维民 白建科[2] 仇银江 马忠美 王红杰[4] 

机构地区：[1]新疆维吾尔自治区地质勘查基金项目管理中心,新疆乌鲁木齐830001 [2]中国地质调查局西安地质调查中心,陕西西安710054 [3]新疆有色地质勘查局地质矿产勘查院,新疆乌鲁木齐830002 [4]中国地质科学院郑州矿产综合利用研究所,河南郑州450006

出　　处：《西北地质》2017年第2期69-79,共11页Northwestern Geology

基　　金：中国地质调查局项目(DD20160006);国家自然科学基金项目(41202077)联合资助

摘　　要：哈拉达拉基性岩体位于西天山特克斯县东北部,主要由橄长岩、橄榄辉长岩、角闪辉长岩和辉长岩组成。作为西天山造山带出露规模最大的基性-超基性侵入杂岩体,其形成时代及构造环境的意义一直是关注的焦点。岩浆演化过程中,通过早期橄榄石和斜长石结晶分离后,残余岩浆侵位形成了辉长岩。笔者对辉长岩进行LA-ICP-MS锆石U-Pb年代学研究,表明辉长岩年龄为(304.5±2.6)Ma(MSWD=0.59,n=25),时代为晚石炭世。通过地球化学分析,表明哈拉达拉辉长岩属于钙碱性系列,富集大离子亲石元素,亏损高场强元素,是地幔基性岩浆上侵与地壳发生混染,同时受流体作用影响形成的产物。结合区域地质资料,认为西天山晚石炭世处于伸展构造环境,哈拉达拉岩体可能与天山造山带后碰撞裂谷演化有关。The Haladala basic pluton,consists of troctolite,olivine gabbro,hornblende gabbro,and gabbro,intruded into Late Carboniferous rocks in the Northeastern Tekesi County,Western Tianshan.As the largest basic-ultrabasic intrusive complex of western Tianshan orogenic belt,the formation age and tectonic environment of the Haladala pluton have always been the focus problem for the evolution of Tianshan orogenic belt.In the process of magma evolution,after the fractional crystallization of olivine and plagioclase,the residual magma intruded and formed gab-bro.LA-ICP-MS zircon U-Pb chronology indicates that the age of gabbro is(304.5 ± 2.6)Ma(MSWD=0.59,n=25).The Haladala gabbro belongs to calc-alkaline series,with the enrichment of large ion lithophile elements and the depletion of high strength field elements.The geochemical characteristics suggest that the Haladala basic pluton was produced by mantle-based magmatic invasion and crustal contamination,and it was affected by the fluid at the same time.Based on the regional geological data,it is concluded that the Western Tianshan was in the extentional setting during the Late Carboniferous,which may be related to the post collision rift evolution of the Tianshan orogenic belt.

关 键 词：哈拉达拉基性岩体 锆石U-PB年龄 裂谷构造环境 西天山 

分 类 号：P597[天文地球—地球化学]