德国格雷夫斯瓦尔德大学M. Arwed Gibb课题组的一项最新研究发现，等深流-漂流档案将晚泥盆世生物事件与周期性缺氧陆架水级联关联起来。这一研究成果于2024年7月24日发表在国际顶尖学术期刊《地质学》上。

本研究识别出的等深流阶地形成于冈瓦纳大陆北部被动北缘的最上斜坡。它的内部被一个顺坡等深流河道和一个位于其下坡边缘的丘状漂流物所包围。相规模和漂流规模等深流特征表明，来自冈瓦纳北部陆表海的高密度、高含盐量、缺氧水的反复溢出驱动了向西北方向的底层流。

这些周期性的溢流通过Ougarta海槽，然后在科里奥利力的作用下向西偏转，越过Tafilalt conttheite阶地，并向下坡倾泻，直到达到密度平衡水平，可能形成了一个中等水团。密集的、缺氧的陆架水的级联支持了为Kellwasser危机和相关泥盆纪缺氧事件提出的透光层富营养化(自上而下)模型。研究结果强调了缺氧溢流与泥盆纪演化事件之间的直接联系。

据悉，研究人员对摩洛哥东部Anti-Atlas泥盆纪等深流沉积体系的分析，揭示了广泛的侵蚀间断和富含有机物的生物碎屑等深流沉积(ORCs)的形成，与Frasnian生物事件期间缺氧水团扩张相一致，最终引发了Kellwasser危机。

附：英文原文

Title: Contourite-drift archive links Late Devonian bioevents with periodic anoxic shelf water cascading

Author: M. Arwed Gibb, Heiko Hüneke, Jayant Jadhav, Laura M. Gibb, Paul Mehlhorn, Oliver Mayer, Z. Sarah Aboussalam, R. Thomas Becker, Ahmed El Hassani, Lahssen Baidder

Issue&Volume: 2024-07-24

Abstract: Analysis of a Devonian contourite depositional system in the eastern Anti-Atlas of Morocco reveals the formation of widespread erosional hiatuses and organic-rich bioclastic contourites (ORCs) coinciding with the expansion of an anoxic water mass during Frasnian bioevents, ultimately culminating in the Kellwasser crisis (Frasnian-Famennian extinction event). The identified contourite terrace formed on the uppermost slope of the northern passive margin of Gondwana. Its inner part was bounded by an along-slope contourite channel and a small mounded drift at its downslope margin. Facies- and drift-scale contourite features evidence northwest-directed bottom currents driven by repeated overflows of dense, highly saline, anoxic water originating from the northern Gondwana Epicontinental Sea. These periodic overflows were channeled through the Ougarta trough, then deflected westward over the Tafilalt contourite terrace by the Coriolis force and cascaded downslope until reaching a density equilibrium level, probably forming an intermediate water mass. The cascading of dense, anoxic shelf water supports the photic-zone eutrophication (top-down) model proposed for the Kellwasser crisis and related Devonian anoxic events. We propose a direct link between the anoxic overflows and the Devonian evolutionary events.

DOI: 10.1130/G52117.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G52117.1/645840/Contourite-drift-archive-links-Late-Devonian