中国科学技术大学李梦涵博士及其团队，在研究斯图特雪球地球之后的冰川消退火山作用和复氧化作用中取得新进展。相关论文发表在2023年9月6日出版的《科学进展》杂志上。

研究人员提出，具有正 Δ ¹⁹⁹Hg 偏移的汞富集表明火山作用增强，可能是由于冰川消退期间陆相岩浆房的减压作用引起的。较厚的负 Δ ³³S_py 地层间隔表明，非冰期间歇期以硫酸盐含量低但在上升为特征。模型结果揭示了通过瑞利蒸馏产生  -0.284‰ 的 Δ ³³S 异常的机制。

研究结果显示，极端的温度和缺氧导致斯图特冰期后绿藻的生产发生明显的延迟，而随后富铁和贫硫酸盐的海洋的复氧化为动物的进化铺平了道路。

据介绍，低温期的斯图特冰期和马里诺冰期的雪球地球冰期包含了一个非冰期的间歇期。在此期间，海绵生物和绿藻生物标志物首次出现。为了了解环境扰动与早期动物进化之间的关系，研究人员测定了中国南方大塘坡组的硫和汞同位素。

附：英文原文

Title: Deglacial volcanism and reoxygenation in the aftermath of the Sturtian Snowball Earth

Author: Menghan Li, Yilun Xu, Lilin Sun, Jiubin Chen, Ke Zhang, Dandan Li, James Farquhar, Xiaolin Zhang, Ruoyu Sun, Francis A. Macdonald, Stephen E. Grasby, Yong Fu, Yanan Shen

Issue&Volume: 2023-09-06

Abstract: The Cryogenian Sturtian and Marinoan Snowball Earth glaciations bracket a nonglacial interval during which Demosponge and green-algal biomarkers first appear. To understand the relationships between environmental perturbations and early animal evolution, we measured sulfur and mercury isotopes from the Datangpo Formation from South China. Hg enrichment with positive Δ ¹⁹⁹Hg excursion suggests enhanced volcanism, potentially due to depressurization of terrestrial magma chambers during deglaciation. A thick stratigraphic interval of negative Δ ³³S_py indicates that the nonglacial interlude was characterized by low but rising sulfate levels. Model results reveal a mechanism to produce the Δ ³³S anomalies down to -0.284‰ through Rayleigh distillation. We propose that extreme temperatures and anoxia contributed to the apparent delay in green algal production in the aftermath of the Sturtian glaciation and the subsequent reoxygenation of the iron-rich and sulfate-depleted ocean paved the way for evolution of animals.

DOI: adh9502

Source: https://www.science.org/doi/full/10.1126/sciadv.adh9502