| 塔里木地块西北缘震旦系发现二叠纪基性岩床侵入事件 |
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| 引用本文： | 吴鸿翔,黄伟康,励音骐,林秀斌,陈汉林,程晓敢,章凤奇.塔里木地块西北缘震旦系发现二叠纪基性岩床侵入事件[J].地质学报,2020,94(6):1869-1882. |
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| 作者姓名： | 吴鸿翔 黄伟康 励音骐 林秀斌 陈汉林 程晓敢 章凤奇 |
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| 作者单位： | 1) 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；
2) 教育部含油气盆地构造研究中心，杭州，310027 |
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| 基金项目： | 本文为国家重点研发计划项目（编号2016YFC0601004）和国家自然科学基金面上项目（编号41772205，417201400，41972217和41472181）和国家科技重大专项项目(编号2017ZX05008001)联合资助的成果。 |
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| 摘 要： | 准确识别侵入岩和火山岩并厘定其形成时代是野外地质调查的一项基础工作,它们对认识区域岩浆事件序列和建立沉积地层年代格架具有重要的作用。塔里木地块西北缘阿克苏地区以出露连续的新元古界和丰富多样的新元古代岩浆岩而成为备受前寒武纪地质研究工作者关注的地区。本文通过遥感影像的识别、野外剖面地质调查和岩石学研究,发现塔里木西北缘阿克苏市西南部的震旦系中发育的基性岩具有典型的岩浆侵入特征,包括局部截切地层、包裹围岩块和内部结晶粗、边缘结晶细等特点。结合锆石U-Pb年代学研究,发现该地区震旦系发育的基性岩浆岩并不全是震旦纪玄武岩,有相当一部分是早二叠世(ca. 290Ma)侵入的辉绿岩岩床,其侵位年龄与塔里木二叠纪大规模溢流玄武岩的喷发时代接近,很可能是塔里木大火成岩省的重要组成部分。这期显著的岩浆热事件可能对该地区前寒武纪岩石重磁化产生重要影响,同时也启示今后开展塔里木北缘震旦纪岩浆作用研究时需要特别引起重视并加以仔细鉴别。
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| 关 键 词： | 塔里木地块 震旦系 基性岩床 二叠纪 塔里木大火成岩省 |
| 收稿时间： | 2020/5/3 0:00:00 |
| 修稿时间： | 2020/5/13 0:00:00 |
Discovery of Permian mafic sills intrusion event in the Sinian system, Northwest Tarim block |
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| WU Hongxiang,HUANG Weikang,LI Yinqi,LIN Xiubin,CHEN Hanlin,CHENG Xiaogan,ZHANG Fengqi.Discovery of Permian mafic sills intrusion event in the Sinian system, Northwest Tarim block[J].Acta Geologica Sinica,2020,94(6):1869-1882. |
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| Authors: | WU Hongxiang HUANG Weikang LI Yinqi LIN Xiubin CHEN Hanlin CHENG Xiaogan ZHANG Fengqi |
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| Abstract: | Correct identification and chronology of intrusive and volcanic rocks is a prerequisite for understanding the succession of regional magmatic events and establishing chronostratigraphic framework. Aksu area, located in the Northwest Tarim block, is known for the successively exposed Neoproterozoic stratum and various kinds of igneous rocks and thus attracts many Precambrian researchers. This work reports typical intrusive characteristics among the basic rocks in the Sinian beds based on remote sensing image recognition, field profile geological survey and petrological study in the southwest Aksu city. These intrusive characteristics include truncating Sinian sandstone layers, wrapping wall rocks and fine- grained tendency of crystal size from the basic rock bed interior to margins. These typical intrusive features, integrated with our U- Pb chronological studies on zircons, indicate that the basic rock in the Sinian beds in the southwest Aksu area are not entirely Sinian erupted basalts- a part of them are actually Early Permian (ca.290 Ma) intrusive dolerite sills which was contemporaneous with the main eruption episode of massive flood basalt during the Permian Tarim Large Igneous Province. We suggest that they are an important component of the Tarim Large Igneous Province. This remarkable magmatic thermal event probably had a great impact on remagnetization of Precambrian rocks in this district. Meanwhile, it also highlights the importance of carefully recognizing and distinguishing the igneous rock types when conducting research on Precambrian magmatism in the Northwest Tarim block. |
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| Keywords: | Tarim block Sinian mafic sills Permian Tarim Large Igneous Province |
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