Mercury enrichments and the Frasnian-Famennian biotic crisis: A volcanic trigger proved?

Abstract

This is a repository copy of Mercury enrichments and the Frasnian-Famennian biotic crisis: A volcanic trigger proved?.

Pulses of enhanced continental weathering associated with multiple Late Devonian climate perturbations: Evidence from osmium-isotope compositions

“…Argon-argon (Ar-Ar) dating of Viluy Trap basalts has indicated a major magmatic pulse of late Frasnian age (~374 Ma; Ricci et al, 2013;Polyansky et al, 2017), with widespread volcanic activity also taking place on several tectonic rift-systems during the Late Devonian (reviewed in Kravchinski, 2012). A precise coincidence between this volcanism and the Upper Kellwasser Event has been inferred on the basis of mercury enrichments within UKW strata (Racki et al, 2018). The very high Os concentration and low Os (i) value of 0.21 from the inferred LKW Horizon observed in this study (Figure 3) may also indicate a major input of unradiogenic Os from primitive mantle-derived volcanism during the earlier event; a meteorite impact might also cause these changes in Os concentration and isotopic composition, but evidence for such a phenomenon during the LKW Event is lacking (Claeys et al, 1996;Racki, 1999;Percival et al, 2018).…”

“…The ultimate causes of the various Late Devonian environmental perturbations remain debated. Numerous triggers have been postulated for the Kellwasser crises, including extra-terrestrial impacts (e.g., Wang, 1992;Claeys et al 1996;Du et al, 2008), large-scale volcanic activity potentially linked to the Viluy Traps in Siberia (e.g., Courtillot et al, 2010;Ricci et al, 2013;Racki et al, 2018), orogenic uplift and erosion (Averbuch et al, 2005), and the expansion of vascular-rooted terrestrial flora (Algeo et al, 1995;Algeo and Scheckler, 1998). Many of the environmental perturbations also appear to have coincided with climate cooling (e.g., Streel et al, 2000;Joachimski and Buggisch, 2002;Balter et al, 2008).…”

“…Consequently, it is unknown how the global Os inventory responded to possible influences from any or all of the postulated meteorite impacts, volcanic activity, or enhanced continental weathering rates thought to have occurred during the various Late Devonian environmental perturbations (e.g., Wang, 1992;Claeys et al, 1996;Algeo and Scheckler, 1998;Averbuch et al, 2005;Chen et al, 2005;Courtillot et al, 2010;Ricci et al, 2013;Whalen et al, 2015;Racki et al, 2018).…”

A stable and productive marine microbial community was sustained through the end‐Devonian Hangenberg Crisis within the Cleveland Shale of the Appalachian Basin, United States

“…The HC decimated ammonoid, trilobite, conodont, and vertebrate taxa, and marked the end of stromatoporoid sponges, though many affected groups recover in the Carboniferous (Caplan & Bustin, 1999;Sallan & Coates, 2010;McGhee et al, 2013). Numerous extinction mechanisms and triggers have been proposed including: oceanwide marine anoxia, volcanism, eustatic change, climate fluctuations (Caplan & Bustin, 1999;Marynowski et al, 2012;Carmichael et al, 2015;Racki, Rakociński, Marynowski, & Wignall, 2018), and the evolution and expansion of land plants (by increasing weathering rates and drawing down CO 2 ; Algeo, Berner, Maynard, & Scheckler, 1995;Tulipani, Grice, Greenwood, Schwark et al, 2015), though there were likely synergistic effects operating that contributed to the ecological crisis. The event was likely rapid (calculated duration of ~50-100 ka; Myrow et al, 2014), marked by glaciation, and globally expressed (Kaiser, Aretz, & Becker, 2015).…”

Anomalous Upper Devonian mercury enrichments: comparison of Inductively Coupled Plasma – Mass Spectrometry (ICP-MS) and Atomic Absorption Spectrometry (AAS) analytical data

“…De tailed anal y sis and in ter preta tion of the world wide anom a lous Hg spikes as so ci ated with the Up per De vo nian biodiversity cri ses, first re ported here for D-C tran si tion, will be given else where. How ever, at least the most dis tinc tive Hg sig nal just be low the F-F bound ary is shown as a prob a ble sig na ture of cat a clys mic vol ca nism that led to the global biodiversity col lapse (Racki et al, 2018).…”