| 华北地台中元古界雾迷山组浅海脉冲式增氧 |
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| 引用本文： | 孙龙飞,汤冬杰,周利敏,方浩,吴孟亭,郭华,周锡强,邹佳男,史晓颖.华北地台中元古界雾迷山组浅海脉冲式增氧[J].古地理学报,2020,22(6):1181-1196. |
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| 作者姓名： | 孙龙飞 汤冬杰 周利敏 方浩 吴孟亭 郭华 周锡强 邹佳男 史晓颖 |
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| 作者单位： | 1. 中国地质大学(北京)生物地质与环境地质国家重点实验室,北京 100083;2. 中国地质大学(北京)地球科学与资源学院,北京 100083;3. 中国地质大学(北京)科学研究院,北京 100083;4. 国家地质实验测试中心,北京 100037;5. 中国地质大学(武汉)生物地质与环境地质国家重点实验室,湖北武汉 430074;6. 中国科学院地质与地球物理研究所新生代地质与环境重点实验室,北京 100029;7. 中国科学院大学,北京 100049 |
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| 基金项目： | 国家自然科学基金项目(编号: 41930320,41972028)、中国科学院地质与地球物理研究所重点研究项目(编号: IGGCAS-201905)、中国地质大学(北京)“求真学人”项目(编号: 2652018005)、中国地质大学(北京)大学生创新创业训练计划项目(编号:S201911415008)共同资助; |
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| 摘 要： | 氧气对真核生物的起源和早期演化至关重要,但是有关元古宙中期大气和浅海氧气浓度的限定却分歧很大,目前存在持续低氧(<0.1%~1%现代大气水平,PAL)、相对高氧(>4%PAL)和动态波动等多种观点。为了进一步揭示真核生物集中分布的浅海水体的氧化还原条件,文中选择华北中元古界雾迷山组四段下部环潮坪碳酸盐岩为研究对象,通过稀土Ce异常重建当时正常浪基面之上海水的氧化还原状态。结果表明,雾迷山组四段下部1段厚约150m的碳酸盐岩地层(~1480-1475Ma)具有明显的Ce负异常(Ce/Ce*=0.82±0.11,n=10),而下伏和上覆地层均为具弱Ce正异常的碳酸盐岩,可能代表了1次持续时间约5Ma的浅海脉冲式增氧过程。该层段的脉冲式增氧可能表明元古宙中期浅海氧气浓度存在频繁波动,并非处于稳定的低氧或相对高氧平台状态。该研究成果有助于进一步确定元古宙中期浅海氧化还原状态和演变特征,并为探讨海水氧化还原状态对早期真核生物演化的影响提供重要信息。
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| 关 键 词： | 碳酸盐岩 Ce异常 硫同位素 脉冲式增氧 真核生物 |
| 收稿时间： | 2020-05-22 |
A pulsed oxygenation in shallow seawater recorded by the Mesoproterozoic Wumishan Formation,North China Platform |
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| Sun Long-Fei,Tang Dong-Jie,Zhou Li-Min,Fang Hao,Wu Meng-Ting,Guo Hua,Zhou Xi-Qiang,Zou Jia-Nan,Shi Xiao-Ying.A pulsed oxygenation in shallow seawater recorded by the Mesoproterozoic Wumishan Formation,North China Platform[J].Journal of Palaeogeography,2020,22(6):1181-1196. |
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| Authors: | Sun Long-Fei Tang Dong-Jie Zhou Li-Min Fang Hao Wu Meng-Ting Guo Hua Zhou Xi-Qiang Zou Jia-Nan Shi Xiao-Ying |
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| Abstract: | Oxygen is crucial for the origin and early evolution of eukaryotes. However,the oxygen levels in the atmosphere and shallow ocean of Mesoproterozoic have been poorly constrained,with varying viewpoints including persistent low(equals to <0.1%~1% of the present atmosphere level,PAL),relatively high(>4%~8% of PAL),and dynamic variation. In order to further constrain the redox conditions in shallow waters where eukaryotes inhabited,the Ce anomaly of the peritidal carbonates from lower Member 4 of the Mesoproterozoic Wumishan Formation in North China was investigated. The results show that the significant negative Ce anomalies(Ce/Ce*=0.82±0.11,n=10)occurs in the carbonate of the lower Member 4 of the Wumishan Formation with the thickness of about 150 m. The carbonate formation with the significant negative Ce anomaly is interlayered between the carbonates with inconspicuous positive Ce anomalies,which may represent a pulsed oxygenation in shallow seawater with a duration of ~5 Ma(~1480-1475 Ma). It reflects that the redox conditions of Mesoproterozoic shallow seawater fluctuated greatly rather than stable at low or relatively high level of oxygen. The results are helpful to determine the evolution of redox state of the Mesoproterozoic shallow sea,and it provides important information for studying the influence of redox state of seawater on the evolution of early eukaryotes. |
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| Keywords: | carbonate rock Ce anomaly sulfur isotope pulsed oxygenation eukaryote |
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