新疆东准噶尔塔克尔巴斯陶一带闪长岩岩石学及地球化学特征

Petrology and Geochemistry of the Taker Basi To Diorite from a Eastern Junggar of Xinjiang

塔克尔巴斯陶闪长岩体位于东准噶尔北缘,乌伦古河断裂南侧,卡拉麦里断裂北侧。该岩体由辉长闪长岩、辉石闪长岩、二长闪长岩组成,SHIRMP锆石U-Pb测年为（362.5±9.4）Ma。岩石属高钾钙碱系列,富集大离子亲石元素Sr,K,Ba,亏损高场强元素Nb,Ta,Ti,Th,其中Ta为0.28×10-6~0.73×10-6,Hf/Ta为7.41~12.86,Hf/Th为0.67~1.44,Zr/Nb为15.25~29.85,且大多数样品的Nb,Ta有较强的亏损等特征,反映岩浆源区可能来自地幔,并与有着明显Nb,Ta亏损的岛弧环境闪长岩相似。岩体高Sr低Y及低Sr/Y值,同时δEu=0.75~1.09,（La/Yb）N=6.04~11.67,暗示岩体中有大陆地壳物质参与。通过获得的SHIRMP锆石U-Pb年龄及岩石地球化学等特征,判断塔克尔巴斯陶岩体产于俯冲岛弧环境,岩体为地幔岩浆来源,并有一定地壳物质参与,同时也约束了东准噶尔地区俯冲-消减作用结束的时限。

Taker BasiTao rock body is located in the northeastern margin of Junggar,south of Wulungu river afault,and the north of Kalamaili fault.The rock are composed of gabbro diorites,pyroxene diorites and monzodiorite,Zircon SHIRMP U-Pb age is（362.5 .4） Ma.The rock is of high-K calc-alkaline,and rock is riched in LILE Sr,K,Ba,flatter HFSE Nb,Ta,Ti,Th,The Ta is between 0.28~0.73μg/g,Hf/Ta value range of 7.41~12.86,Hf/Th value range of 0.67~1.44,Zr/Nb value range of 15.25~29.85,and most of the samples are more strongly depleted in Nb,Ta,characteristics above show that magmatic source is stem from mantle,and simillar withDiorite which come from island arc environment;the rock mass with high Sr low Y and Sr/Y value Characteristics,the Eu（0.75~1.09） and（La/Yb）N（6.04~11.67） value indicates the rock mass with the participation of certain crustal material.In this paper,through the age of SHIRMP zircon U-Pb and the rock geochemical characteristics,Judge the rock mass is from subduction island arc environment,the rock megma source comes from mantle and crustal materials must have contributed to the formation of the rock,at the same time,it restrains the end of Subduction effect of the eastern Junggar.