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古生物学家和生物地层学家经长期研究认为 ,显生宙以来的地球生物演化进程中曾在 2 .5亿年前 ,亦即 ,在对应于二叠系 /三叠系 (P/T)界线的年代附近 ,发生过全球性最为严重的一次生物大灭绝。中国煤山剖面是目前唯一被确定的全球P/T标准层型界线与点的剖面 ,俗称“金钉子”。因此 ,关于该剖面的事件界线层的地球化学研究具有典型意义 ,对理解P/T转折期发生的灾变事件和环境变化具有全局性的科学价值。沿着曾间接提出的P/T转折期可能的全球酸雨事件的传统思路和全球海洋酸性化事件的新思路 ,实验证实 :煤山剖面P/T界线粘土层的潮湿白粘土呈强酸性 ,校正酸度值达到pH0 .80～ 1.32。这一发现向寻找P/T转折期全球海洋酸性化的直接证据迈进了重要一步
Paleontologists and biostratigraphic scientists have long argued that during the evolution of the Earth’s biology from the Phanerozoic, about 250 million years ago, that is, corresponding to Permian / Triassic (P / T) Near the boundary line, the world’s most serious biological extinction took place. The Meishan section in China is currently the only section of the global P / T standard layer boundary and point profile known as “Golden Nail”. Therefore, the geochemical study on the event boundary layer of this section is of typical significance, which is of overall scientific value for understanding the catastrophic events and environmental changes occurring during the P / T transition. According to the indirect idea of possible global acid rain events and global ocean acidification events that have been put forward at the P / T transitional period indirectly, the experiment confirms that the wet white clay in P / T boundary clay layer of coal seam section is strongly acidic, Acidity reaches pH0 .80 ~ 1.32. This finding is an important step toward finding direct evidence of global ocean acidification during the P / T transition