加拿大地质调查局 Stephen E. Grasby 团队近日在研究二叠纪—三叠纪大灭绝期间“海雪”中取得一项新成果。这一研究成果发表在2023年11月29日出版的国际学术期刊《地质学》上。

该团队研究人员对新西兰 Waiheke 剖面的有机物进行了检测，结果表明，这些沉积物主要由钙铝石组成，由藻华期间产生的单细胞原生生物或群体浮游植物组成，被称为“海雪”。研究人员模拟了西伯利亚暗色岩大火成岩省火山喷发产生的火山灰的影响，并论证了它们给泛大洋提供了磷和铁，诱发“海雪”的形成和显著的碳下降，标志着二叠纪—三叠纪大灭绝期间的主要生物华。

据介绍，二叠纪—三叠纪大灭绝(PTME)期间，以无机和有机碳(C)同位素的重大偏移为标志。碳循环模型预测，这些趋势是由生产力的大幅提高所驱动的，然而有机碳在大多数二叠纪—三叠纪大灭绝期间，陆架沉积序列中没有富有机碳的岩石记录。日本和新西兰已发现的罕见深海平原记录中，报告了异常富碳相，二叠纪—三叠纪大灭绝期间的黑色页岩是异常富有机质的单元。

附：英文原文

Title: Marine snowstorm during the PermianTriassic mass extinction

Author: Stephen E. Grasby, Omid H. Ardakani, Xiaojun Liu, David P.G. Bond, Paul B. Wignall, Lorna J. Strachan

Issue&Volume: 2023-11-29

Abstract: The PermianTriassic mass extinction (PTME) interval is marked by major excursions in both inorganic and organic carbon (C) isotopes. Carbon cycle models predict that these trends were driven by large increases in productivity, yet organic Crich rocks are not recorded in most PTME shelf sedimentary successions. Anomalous C-rich facies have been reported from rare abyssal plains records now exposed in Japan and New Zealand, where black shales at the PTME are extraordinarily organic-rich units. We examined organic matter at the Waiheke, New Zealand, section, and results show that these deposits are dominated by lamalginites composed of unicellar solitary or colonial phytoplankton produced during algal blooms that falls as “marine snow.” We modeled the impact of ash fall from eruptions in the Siberian Traps large igneous province and argue that they fertilized the Panthalassa Ocean with P and Fe, leading to a marine “snowstorm” and significant C drawdown marking this major biobloom during the PTME.

DOI: 10.1130/G51497.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G51497.1/629933/Marine-snowstorm-during-the-Permian-Triassic-mass