| The Permian mafic intrusive events in the northwestern margin of the Tarim Basin and their tectonic significanceSCIEI北大核心CSCD |
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| 引用本文： | 程小鑫,吴鸿翔,孙大亥,黄伟康,陈汉林,林秀斌,朱孔阳,章凤奇.The Permian mafic intrusive events in the northwestern margin of the Tarim Basin and their tectonic significanceSCIEI北大核心CSCD[J].岩石学报,2022,38(3):743-764. |
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| 作者姓名： | 程小鑫 吴鸿翔 孙大亥 黄伟康 陈汉林 林秀斌 朱孔阳 章凤奇 |
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| 作者单位： | 浙江大学地球科学学院, 浙江省地学大数据与地球深部资源重点实验室, 杭州 310027;教育部含油气盆地构造研究中心, 杭州 310027;浙江大学地球科学学院, 浙江省地学大数据与地球深部资源重点实验室, 杭州 310027;浙江省地质调查院, 杭州 311203 |
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| 基金项目： | 本文受国家自然科学基金基础科学中心项目（51988101）、国家自然科学基金项目（42072233）和国家重点研发计划项目（2016YFC0601004）联合资助. |
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| 摘 要： | 塔里木大火成岩省是我国境内发现的两个重要的二叠纪大火成省之一，不仅有大规模的溢流相玄武岩喷发，还有复杂多样的侵入岩及其组合。以往的研究主要集中在二叠系等显生宙地层发育区，对于前寒武系等古老层系中是否存在二叠纪岩浆侵入未引起重视。本文通过野外地质调查，在阿克苏地区前寒武系中识别出数条侵入南华系的基性岩墙和较大规模侵入震旦系的基性岩床。岩墙、岩床与围岩之间均显示出典型的侵入接触关系，包括岩体内部结晶粗、边部结晶细的淬冷边结构、岩床顶底面显著的切层现象以及包裹围岩团块等；显微镜下观察表明，辉绿岩具有典型的辉绿结构和嵌晶含长结构。锆石U-Pb年代学结果表明，侵入下震旦统的辉绿岩岩床和侵入南华系的辉绿岩岩墙的侵位时代在误差范围内基本一致，约为290Ma。岩石地球化学特征表明，辉绿岩岩床具有与洋岛玄武岩(OIB)相似的稀土及微量元素配分模式，结合Sr-Nb-Pb同位素测试结果，认为它们来源于碳酸盐化的富集型岩石圈地幔部分熔融，而辉绿岩岩墙具有Nb、Ta、Zr、Hf等负异常的地球化学特征，可能来自曾被俯冲相关流体/熔体交代的岩石圈地幔源区。本文的早二叠世辉绿岩岩床和岩墙的形成时代、岩浆源区和岩浆演化...
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| 关 键 词： | 塔里木盆地 二叠纪 大火成岩省 辉绿岩岩床和岩墙 地幔柱 壳幔作用 |
| 收稿时间： | 2021/5/28 0:00:00 |
| 修稿时间： | 2021/11/8 0:00:00 |
The Permian mafic intrusive events in the northwestern margin of the Tarim Basin and their tectonic significance |
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| CHENG XiaoXin,WU HongXiang,SUN DaHai,HUANG WeiKang,CHEN HanLin,LIN XiuBin,ZHU KongYang,ZHANG FengQi.The Permian mafic intrusive events in the northwestern margin of the Tarim Basin and their tectonic significance[J].Acta Petrologica Sinica,2022,38(3):743-764. |
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| Authors: | CHENG XiaoXin WU HongXiang SUN DaHai HUANG WeiKang CHEN HanLin LIN XiuBin ZHU KongYang ZHANG FengQi |
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| Institution: | Key Laboratory of Geoscience Big Data and Deep Earth Resources of Zhejiang Province, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China;Research Center for Structures in Oil & Gas Bearing Basins, Ministry of Education, Hangzhou 310027, China;Key Laboratory of Geoscience Big Data and Deep Earth Resources of Zhejiang Province, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China;Zhejiang Institute of Geological Survey, Hangzhou 311203, China |
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| Abstract: | The Tarim Large Igeneous Province is one of the two important Permian Large Igeneous Provinces discovered in China, which not only has large-scale overflow basalt eruptions, but also has complex and diverse intrusive rocks and their assemblages. Previous studies mainly focused on the Permian and other Phanerozoic strata, but did not pay attention to the existence of Permian magmatic intrusions in the Precambrian strata. Based on geological survey of field sections, we identified two types of basic rocks in the Precambrian sedimentary strata in the Aksu area, i.e., the basic dikes intruding into the Nanhua System and the basic sills intruding into the Middle and Lower Sinian System. These basic dikes and sills show typical intrusive contact relationship with wall rocks, which is supported by the quenched edge structure showing coarse and fine crystals respectively in the interior and edge of the sills, truncation of the bottom and top of the sills against the sandstone layers, and these basic intrusive rocks wrapping the wall rocks mass, and so on. The microscopic study shows that the basic intrusive rocks are mainly characterized by typical diabasic structure and poikilitic structure. Zircon U-Pb geochronological results show that the intrusive ages of the Lower Sinian diabase sills and the Nanhua diabase dikes are generally consistent within the test error range, about 290Ma. The geochemical characteristics of the diabase sills show that the rare and trace elements distribution pattern of the diabase bed is similar to that of the Ocean Island basalt (OIB). Combined with the Sr-Nb-Pb isotope test results, it is believed that the diabase sills are derived from the partial melting of the enriched lithosphere mantle due to carbonation. The diabase dikes have the negative anomaly characteristics of Nb, Ta, Zr and Hf, and they were derived from lithospheric mantle sources that had been metasomatized by subduction-related fluids/melts. In addition, these Early Permian diabase dikes and sills are very similar to the mafic rocks of the Tarim Large Igneous Province including their formation age, magmatic source, magmatic evolutionary characteristics and tectonic setting, and their adjacent spatial development. Therefore, we believe that these intrusive basic rocks belong to the important component of the early basic magma of the Tarim Large Igneous Province. This means that there are not only large-scale basaltic eruptions, but also a large number of basic intrusions in Precambrian strata during the early stage of the Tarim Large Igneous Province. This study enriched the rock types and spatial distribution of the Tarim Large Igneous Province, and promoted our understanding on the Early Permian crust-mantle interacting processes in the deep lithosphere. |
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| Keywords: | Tarim Basin Permian Large Igneous Province Diabase dikes and sills Mantle plume Crust-mantle interaction |
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