End-Permian catastrophic event of marine acidification by hydrated sulfuric acid: Mineralogical evidence from Meishan Section of South China
End-Permian catastrophic event of marine acidification by hydrated sulfuric acid: Mineralogical evidence from Meishan Section of South China
复制标题
DOI：
10.1360/02tb9307
复制
发表时间：
2002-08
影响因子：
--
通讯作者：
Handong Liang
中科院分区：
文献类型：
--
作者：
Handong Liang
浙江长兴梅山剖面25层的“白色粘土”是二叠-三叠系界线的标志。本文对该白色粘土及其上覆和下伏层序进行了详细的矿物学研究。调查产生了三个结果，有助于更好地理解EPTB大灭绝的情景。(i)在剖面中的白色粘土基底上首次发现了水平分布的红色针铁矿富集微层（0.3 mm）。微层应被视为一个宏观的地球化学指标，自然跟踪灾难性的启动在EPTB。(ii)由于白色粘土中碳酸盐矿物的空白，发现海相碳酸盐沉积的中断。这一发现提供了海洋酸化事件的重要证据，该事件将发生在古海洋中，海洋酸度估计至少为pH <4.0，并由最终的灾难性事件引发。(iii)石膏是典型的硫酸盐矿物，在该白色粘土中含量很高（34%）。这一事实表明，水合硫酸可能存在于海洋底部，从而以化学方式造成海洋酸化事件。此外，海洋酸化事件不仅可以直接杀死一些海洋生物物种，还可能导致一些衍生事件，如底栖缺氧和全球温度升高等。
The event Permian-Triassic boundary (EPTB) is well marked by the famous “white clay” of bed 25 in Meishan Section located in Changxing county, Zhejiang province of China. In this note, the white clay as well as its overlying and underlying sequences is investigated particularly for mineralogical records. The investigation yields three findings that contribute to better understanding the scenario of the EPTB mass extinction. (i) A red goethite-rich microlayer (0.3 mm) is first recognized to be horizontally widespread on the base of the white clay in the section. The microlayer should be considered as a macro geochemical indicator naturally tracing a catastrophic initiation at the EPTB. (ii) An interruption of marine carbonate deposition is discovered due to blank of carbonate minerals in the white clay. The discovery provides significant evidence of a marine acidification event that would occur in the paleo-ocean with marine acidity estimated at pH <4.0 at least and be triggered by the ultimate catastrophic event. (iii) Gypsum as typical sulfate mineral is identified to exist in the white clay with high abundance (34%). The fact reveals that hydrated sulfuric acid would be present at the bottom of the ocean and thus chemically create the marine acidification event. Furthermore, it is suggested that the marine acidification event could not only directly kill some marine biotic species but also result in some derivative events such as the benthic anoxia and the temporal global temperature-increase during the EPTB mass extinction.