许骏,杨利亚,陈曦,陈磊,张文东,王丰丰,王燕超,王洋.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[J].矿产勘查,2020,11(9):1797-1811 |
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 |
投稿时间:2019-11-14 |
DOI: |
中文关键词: 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 |
英文关键词: zircon U-Pb dating,major-tace elements, Sr-Nd isotope, intrusive rocks,Kalatage area,Xinjiang |
基金项目: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)及中国地质调查局项目(编号:DD20190159-08、1212011140056)资助。 |
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中文摘要: |
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;εNd(t)为正且稳定,Isr变化大,t2DM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。 |
英文摘要: |
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 t2DM is 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. |
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