| 何鹏,芦西战,杨睿娜,陈培伟,刘晓,张焕,贺晓天,李福斌.阿尔金北缘尧勒萨依河口Ⅰ型花岗岩岩石地球化学、锆石U-Pb年代学研究[J].矿产勘查,2020,11(9):1822-1830 |
| 阿尔金北缘尧勒萨依河口Ⅰ型花岗岩岩石地球化学、锆石U-Pb年代学研究 |
| Petrogeochemistry, zircon U-Pb chronology of I type granite from Yaolesayi estuary, Northern Altun |
| 投稿时间：2020-04-09 |
| DOI： |
| 中文关键词: 岩石地球化学 花岗岩 锆石U-Pb年代学 构造 北阿尔金 |
| 英文关键词: petrogeochemistry, granite, U-Pb chronology, tectonic, North Altyn-Tagh |
| 基金项目:新疆维吾尔自治区地质勘查基金项目(编号:K16-1-LQ12)资助。 |
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| 中文摘要: |
| 阿尔金北缘尧勒萨依河口花岗岩主要由黑云二长花岗岩组成。为确定该地区侵入岩源区性质、形成时代和地质背景,对其进行了地球化学、构造环境及锆石U-Pb年代学研究,认为研究区花岗岩为高硅(SiO2=67.48%～70.75%)、高钾(K2O=5.03%～7.66%)、富碱(Na2O+K2O=8.45%～11.32%)的特征,岩石里特曼指数δ=2.92～5.08,属碱性系列；铝过饱和指数(A/CNK)=0.8～1.15,基本为准铝质系列岩石；稀土总量偏高,轻稀土元素富集,(La/Yb)N=24.67～117.33,轻、重稀土元素分馏明显,Eu有弱负异常(δEu=0.59～0.97),无明显Ce异常(δCe=0.99～1.05)。富集轻稀土和大离子亲石元素(Rb、K、Th、U),Nb、Ta、P、Ti等高场强元素相对亏损,具有弧形岩浆岩的地球化学特征。花岗岩锆石U-Pb加权平均年龄为(237.3±2)Ma,为中三叠世岩浆活动产物。研究表明,该区侵入岩属I型花岗岩,具有陆陆碰撞型花岗岩的特征,属同碰撞阶段,为壳幔混合源花岗岩类型。 |
| 英文摘要: |
| The granite from Yaolesayi estuary in north Altyn-Tagh is mainly composed of biotite monzogranite. In order to find out the origin, formation age and tectonic setting of granites in this area, studies of zircon U-Pb chronology, tectonic environment and geochemistry were carried out. We have learnt that granite in research area is rich in silicon (SiO2=67.48%-70.75%), potassium (K2O=5.03%-7.66%), and alkali(Na2O+K2O=8.45%-11.32%). The Rittmann index of granite is 2.92-5.08 which shows a characteristics of alkaline series. The aluminum oversaturated index (A/CNK) of granite is 0.8-1.15, which is a metaluminous series. The granite is characterized by high ∑REE(∑REE 161.23×10-6-1217.10×10-6), LREE enrichment, notable light and heavy REE fractionation ((La/Yb)N=24.67-17.33), negative Eu anomaly (δEu=0.59-0.97), inapparent positive Ce anomaly (δCe=0.99-1.05), rich LILEs such as Rb,K,Th and U and depleted HFSEs such as Nb,Ta,P and Ti. LA-ICP-MS U-Pb dating obtains the age of (237.3±2)Ma, which is Middle Triassic. These characteristics suggest that the granite in research area is typical I-type granite and may be continent-continent collisional granite, which is produced during the stage of syn-collision. The granite magma is proved to be a crust-mantle mixing origin. |
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