| 大火成岩省与大规模黑色页岩沉积的成因联系及其意义 |
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| 引用本文： | 张拴宏,裴军令,胡国辉,张琪琪,税国豪,赵越.大火成岩省与大规模黑色页岩沉积的成因联系及其意义[J].地质力学学报,2019,25(5):920-931. |
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| 作者姓名： | 张拴宏 裴军令 胡国辉 张琪琪 税国豪 赵越 |
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| 作者单位： | 1.中国地质科学院地质力学研究所, 北京 100081 |
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| 基金项目： | 国家自然科学基金项目（41725011,41920104004）;国家重点研发计划课题（2018YFC0603802） |
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| 摘 要： | 大火成岩省对全球性大气-海洋环境的巨变及生物灭绝有非常重要的影响。已有研究结果表明,显生宙（即寒武纪以来）大火成岩省与全球大洋缺氧与生物灭绝有明显的成因联系,显生宙国际地质年代表中多个金钉子均与以大火成岩省、黑色页岩及生物灭绝为代表的全球性地质事件相对应。但由于对前寒武纪,特别是"地球中年期"（18~8亿年,"枯燥的10亿年"）大气氧浓度、海洋的氧化-还原状态及生物门类及演化认识的局限性,关于前寒武纪大火成岩省与环境的影响及其与黑色页岩沉积的成因联系一直很不清楚。通过对全球哥伦比亚（奴那）超大陆中约13.8亿年全球性大火成岩省及黑色页岩沉积时空分布的研究,发现这些大火成岩省及黑色页岩的分布有明显的规律。约13.8亿年大火成岩省广泛分布在北美、格陵兰、西伯利亚、波罗地、卡拉哈里、刚果、西非、亚马逊、南极及西澳大利亚等大陆上;而同期的黑色页岩在华北及北澳大利亚克拉通广泛分布,在西伯利亚、巴西及印度等克拉通也有分布。根据这些黑色页岩在超大陆重建图中的空间分布,提出了哥伦比亚（奴那）超大陆中这些广泛分布的约13.8亿年黑色页岩可能沉积于连通的大型海相盆地,而不是以往所认为的局部封闭的小盆地。通过约13.8亿年大火成岩省与黑色页岩内火山灰（斑脱岩）年龄的对比,进一步提出约13.8亿年存在一次与全球性大火成岩省有关的大洋缺氧事件,以此期大火成岩省与黑色页岩为代表的全球性地质事件为中元古代盖层系与延展系提供了精确的界限年龄为1383 Ma。初步的研究结果还显示,"地球中年期"可能还有多期的大火成岩省与黑色页岩沉积有时空联系,有望为晚前寒武纪地质年代表划分提供新的事件约束。
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| 关 键 词： | 大火成岩省 黑色页岩沉积 大洋缺氧事件 地质年代表划分 |
| 收稿时间： | 2019/9/1 0:00:00 |
| 修稿时间： | 2019/9/23 0:00:00 |
GENETIC LINK BETWEEN LARGE IGNEOUS PROVINCES AND LARGE VOLUMES OF BLACK SHALE DEPOSITION AND ITS IMPLICATIONS |
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| ZHANG Shuanhong,PEI Junling,HU Guohui,ZHANG Qiqi,SHUI Guohao and ZHAO Yue.GENETIC LINK BETWEEN LARGE IGNEOUS PROVINCES AND LARGE VOLUMES OF BLACK SHALE DEPOSITION AND ITS IMPLICATIONS[J].Journal of Geomechanics,2019,25(5):920-931. |
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| Authors: | ZHANG Shuanhong PEI Junling HU Guohui ZHANG Qiqi SHUI Guohao and ZHAO Yue |
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| Institution: | 1.Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China2.Key Laboratory of Paleomagnetism and Tectonic Reconstruction, Ministry of Natural Resources, Beijing 100081, China |
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| Abstract: | Large igneous provinces (LIPs) have a significant influence on global climate changes and mass extinction events. Previous results show that some of the Global Boundary Stratotype Section and Points (GSSPs) in the Phanerozoic international geologic time scale are corresponding to the coeval global-scale LIPs, mass extinction events and/or ocean anoxic events (OAEs) represented by black shales. However, due to limited knowledge of atmospheric oxygen concentrations, ocean redox conditions and early fossils during the Meso-Neoproterozoic Era prior to the Ediacaran period, little is known on the climate and environmental effects of LIPs and link between LIPs and black shales during a billion years in "Earth''s Middle Age" (or "Boring Billion") from 1800 Ma to 800 Ma. Recent results on global distribution of the~1380 Ma LIPs and black shales indicate a temporal and genetic link between the~1380 Ma LIPs and black shales in the Columbia (Nuna) supercontinent. The~1380 Ma LIPs are widely distributed in Baltica, North America, Greenland, Siberia, Kalahari, Congo, West Africa, Amazonia, East Antarctica and West Australia; the coeval black shales have been identified in North China and Northern Australia Graton, and probably in Siberia, Brazil and India Cratons. We proposed that the~1380 Ma black shales were deposited in an and/or several large marine basins, not some restricted basins as previously regarded. Comparisons of the baddeleyite/zircon U-Pb ages of~1380 Ma LIPs and zircon U-Pb ages of tuffs from the black shales within the Xiamaling Formation indicate that global deposition of the~1380 Ma black shales are related to an oceanic anoxic event induced by environment effects of the~1380 Ma LIPs, and the coeval black shales and LIPs provide a robust natural marker for the Calymmian-Ectasian boundary at 1383 Ma. Preliminary results on global distribution of other Meso-Neoproterozoic LIPs and black shales suggest that several other stages of LIPs in "Earth''s Middle Age" are correlated with coeval black shales and can potentially provide more natural markers for the Meso-Neoproterozoic geological time scale. |
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| Keywords: | large igneous provinces (LIPs) black shale sediments oceanic anoxic events (OAEs) subdivision of geologic time scale |
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