Mercury Anomalies Link to Extensive Volcanism Across the Late Devonian Frasnian–Famennian Boundary in South China

Jiawei Zhang,Lingyun Liu,Weipeng Liu,Taiping Ye,Yue Wang,Changzhou Deng,Zuoqi Tang,Weian Liang

doi:10.3389/feart.2021.691827

Abstract

The Late Devonian Frasnian–Famennian (F–F) mass extinction has been long-time debated by non-volcanic causes, extra-terrestrial impacts, and large igneous province (LIP) eruptions. To better understand the ultimate cause of the F–F mass extinction, here we investigate the chemostratigraphy of mercury (Hg) and total organic carbon (TOC) on two marine F–F strata in the Dushan area, South China. In both sections, high Hg and Hg/TOC anomalies were observed near the F–F boundary. These anomalies are in line with those recently observed in Morocco, Germany, Poland, and north Russia, suggesting a global Hg flux. The Late Devonian LIP eruptions, which are believed to have emitted massive amounts of Hg, could be responsible for the global Hg and Hg/TOC anomalies around the F–F boundary. The observed Hg and Hg/TOC anomalies coincide with the extinction of Frasnian fauna in the Dushan area, implying a causal link between the Viluy, Kola, and Pripyat-Dnieper-Donets LIP eruptions and the F–F mass extinction.

Highlights

The Late Devonian Frasnian–Famennian (F–F) transition witnessed one of the “Big Five” mass extinctions which killed at least 40% of all species during the Phanerozoic (e.g., Stanley, 2016)
The rocks mainly consist of dolomite (88–97%) with minor illite, zeolite, calcite, quartz, variable fossil fragments, and organic matter
Organic matter (OM) drawdown plays a critical role in Hg burial onto the seafloor due to its strong affinity to Hg (Sanei et al, 2012; Grasby et al, 2019)

Summary

Introduction

The Late Devonian Frasnian–Famennian (F–F) transition witnessed one of the “Big Five” mass extinctions which killed at least 40% of all species during the Phanerozoic (e.g., Stanley, 2016). Three main Late Devonian extinction events occurred within an interval of 0.7 Ma from the latest Frasnian to the earliest Famennian stages These three extinction events were named the Lower Kellwasser Event (372.5 Ma) from the latest Frasnian stage, the Upper Kellwasser Event near the F–F boundary The Late Devonian Viluy LIP (Ricci et al, 2013) in Siberia and the Kola and Pripyat-Dnieper-Donets LIPs (Puchkov et al, 2016) in Baltica are temporally

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Conclusion