| 论地学幸存者效应——以中上扬子五峰龙马溪组页岩沉积环境为例 |
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| 引用本文：毛小平,陈修蓉.2025.论地学幸存者效应——以中上扬子五峰龙马溪组页岩沉积环境为例[J].地球学报,46(4):659-710. |
| DOI：10.3975/cagsb.2024.111511 |
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| 基金项目:国家能源碳酸盐岩油气重点实验室开放基金课题“基于浅陆封寒思路的深层-超深层古老烃源岩有机质富集机制”(编号: 33550000-24-ZC0613-0105); 贵州省科技计划项目“矿产资源数字化勘查开发技术推广”(编号: 黔科合成果[2022]重点003) |
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| 中文摘要:黑色页岩记录了大量古环境信息, 与伴生的各种成矿元素、地质现象之间可能存在密切的成因和空间关系。以黑色页岩为切入点, 准确分析其沉积环境和有机质的富集规律, 将有助于寻找大矿、富矿, 并能对一些重大地质事件进行更为合理的解读。因此本文研究具有重要意义。通过分析现代沉积固碳规律, 结合古代环境的研究, 探讨了五峰组—龙马溪组黑色页岩的沉积环境及其伴生元素的相关性, 提出了地学幸存者效应。结果表明, 较封闭的水体环境是有机质及伴生矿物质聚集的场所, 富集后成为地质历史的幸存者保存至今, 而较开阔的水体环境因稀释和分解等原因无法有效富集。沉积物中有机质的分解效率对温度的敏感性远大于氧化还原条件。在寒温带, 低分解效率更易保存和富集有机质。因此得出结论, 四川盆地五峰组—龙马溪组页岩发育于冷湿气候和海退过程下的较封闭的潟湖环境; 气候和水体封闭性是影响页岩沉积时期有机质富集的两个主要因素; 富有机质的页岩与其伴生元素之间不存在因果关系, 符合地学幸存者效应。本研究将为我们提供一个新的视角, 帮助理解页岩有机质的富集环境。 |
| 中文关键词:黑色页岩 沉积环境 古气候 局限环境 幸存者偏差 |
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| The Survivor Effect of Geoscience: A Case Study of the Shale Sedimentary Environment of the Wufeng–Longmaxi Formation in the Middle–Upper Yangtze Region |
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| Abstract:Black shale serves as a significant repository of paleoenvironmental information, exhibiting a close genetic and spatial relationship with various associated mineralization elements and geological phenomena. By focusing on black shale and accurately analyzing its depositional environment and the mechanisms governing organic matter enrichment, researchers can identify large ore deposits and rich ore bodies, thereby offering a more nuanced interpretation of major geological events. Consequently, this research holds substantial significance. This study discusses the correlation between the depositional environment of the Wufeng Formation–Longmaxi Formation black shale and its associated elements by analyzing the principles of modern sedimentary carbon sequestration and integrating them with ancient environmental studies. Furthermore, the concept of the geoscientific survivor effect is proposed. The findings suggest that relatively closed water environments serve as focal points for the accumulation of organic matter and associated minerals. Following enrichment, these materials become remnants of geological history, preserved to the present day, whereas more open water environments are less effective at enrichment due to dilution and decomposition. Notably, the efficiency of organic matter decomposition in sediments is significantly more sensitive to temperature variations than to redox conditions. In cold temperate zones, low decomposition efficiency facilitates the preservation and enrichment of organic matter. It can be concluded that the Wufeng Formation–Longmaxi Formation shale in the Sichuan Basin developed in a relatively closed lagoon environment characterized by a cold and humid climate, alongside a marine regression; climate and water closure are the two primary factors influencing organic matter enrichment during the shale deposition period. Importantly, there is no causal relationship between organic-rich shale and its associated elements, which aligns with the geological survivor effect. This study offers a novel perspective that enhances our understanding of the enrichment environment of shale organic matter. |
| keywords:black shale sedimentary environment paleoclimate limited environment survivor bias |
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