东天山卡拉塔格矿集区奥陶—志留纪侵入岩地球化学特征及成因  

Geochemical characteristics and genesis of Ordovician-Silurian intrusive rocks from the Kalatag ore cluster area,east Tianshan

作　　者：许骏 杨利亚[2] 陈曦[2] 陈磊 张文东 王丰丰 王燕超 王洋 XU Jun;YANG Liya;CHEN Xi;CHEN Lei;ZHANG Wendong;WANG Fengfeng;WANG Yanchao;WANG Yang(Sichuan Metallurgical and Geological Exploration Bureau Chengdu Geological Research Institute,Chengdu 610203,Sichuan,China;Beijing Institute of Geology for Mineral Resources,Beijing 100012,China;School of Earth Sciences,East China University of Technology f Nanchang 330013,Jiangxi,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Ministry of Education),School of Geosciences and Irtfo-Physics,Central South University,Changsha 410083,Hunan,China;Hami Hongshi Mining Co.,LTD.,Hami 839000,Xinjiang,China)

机构地区：[1]四川省冶金地质勘查局成都地质调查所,四川成都610203 [2]北京矿产地质研究院,北京100012 [3]东华理工大学地球科学学院,江西南昌330013 [4]中南大学地球科学与信息物理学院有色金属成矿预测与地质环境监测教育部重点实验室,湖南长沙410083 [5]哈密红石矿业有限公司,新疆哈密839000

出　　处：《矿产勘查》2020年第9期1797-1811,共15页Mineral Exploration

基　　金：国家重点研发计划(编号:2018YFC0604006);新疆高层次人才引进工程全职创新人才经费(编号:新人社函〔2019〕39号);国家自然科学基金项目(编号:41572077);中国地质调查局项目(编号:DD20190159-08、1212011140056)资助。

摘　　要：卡拉塔格矿集区位于东天山大南湖岛弧带,大量古生代岩浆岩的发育,在研究东天山古生代弧盆演化上具有天然优势。本文对矿集区内侵入岩进行地球化学研究,结果表明,区内侵入岩表现出低-中钾、富钠、过铝质、钙碱性特征,富集Rb、Ba、K等大离子亲石元素,而亏损Nb、Ta、P等元素;ε_(Nd)(t)为正且稳定,Isr变化大,t_(2DM)较年轻;闪长岩和花岗闪长岩LA-ICP-MS锆石U-Pb加权平均年龄为(449. 9±3. 6) Ma和(435. 5±3. 4) Ma。综合分析认为,区内侵入岩皆为成熟岛弧产物,岩浆来源可能为地幔,为流体上升交代地幔楔橄榄岩发生部分熔融而形成。Sr-Nd同位素暗示基底可能存在古地壳,但影响极其有限。岩石年代学表明俯冲活动从奥陶纪就已开始,大南湖—头苏泉岛弧带是康古尔洋向北俯冲的产物。Kalatag ore cluster area is located in Dananhu island arc belt of East Tianshan where a large number of Paleozoic magmatic rocks have developed as a natural research advantage for evolution of Paleozoic arc basin in East Tianshan. In this paper,the geochemical study of intrusive rocks in ore cluster area shows that those rocks have low-medium K,rich-Na,peraluminous,and calcium-alkaline characteristics. They are enriched large-ion lithophile element Rb,Ba,and K,while depleted Nb,Ta,P and other elements;The values of εNd( t) are positive and stable,the values of Isr change greatly,and the age of t2DMis young;this article obtained the weighted average age of LA-ICP-MS zircon U-Pb is( 449.9±3.6) Ma for diorite and( 435.5±3.4) Ma for granite. According to comprehensive analysis,the intrusive rocks in this area are all mature island arc products,and the source of magma may be the mantle,which are formed by fluid ascending to partial melt the metasomatized peridotite of mantle wedge. The Sr-Nd isotope suggests that there may be paleo-crust in the basement,but its impact is extremely limited. Lithochronology suggests that subduction began in the Ordovician and may indicate the Dananhu-Tousuquan Island arc was formed because of northward subduction of the kanggur Ocean.

关 键 词：锆石U-PB测年 主微量元素 SR-ND同位素 侵入岩 卡拉塔格矿集区 新疆 

分 类 号：P581[天文地球—岩石学]