Abstract
Abstract Large spikes in mercury (Hg) concentration are observed globally at the latest Permian extinction (LPE) horizon that are thought to be related to enhanced volcanic emissions of the Siberian Traps large igneous province (LIP). While forming an effective chemostratigraphic marker, it remains unclear whether such enhanced volcanic Hg emissions could have generated toxic conditions that contributed to extinction processes. To address this, we examined the nature of enhanced Hg emissions from the Siberian Traps LIP and the potential impact it may have had on global ecosystems during the LPE. Model results for a LIP eruption predict that pulses of Hg emissions to the atmosphere would have been orders of magnitude greater than normal background conditions. When deposited into world environments, this would have generated a series of toxic shocks, each lasting >1000 yr. Such repeated Hg loading events would have had severe impact across marine trophic levels, as well as been toxic to terrestrial plant and animal life. Such high Hg loading rates may help explain the co-occurrence of marine and terrestrial extinctions.
Highlights
Large igneous provinces (LIPs) have shaped evolution of life on the planet
The total Hg mass released by the Siberian Traps, estimated to be ∼4.0 × 108 Mg based on known relationships to SO2 emissions (Grasby et al, 2015), was distributed as a function of eruption volume generated in our model, such that the temporal variations of Hg emissions to the atmosphere are directly associated with the modeled eruption rate
Hg release is characterized by a series of pulsed emissions to the atmosphere throughout the LIP event, rather than a constant increased emission rate
Summary
Defined as emplacements of >100,000 km of mainly mafic magma (Ernst and Youbi, 2017), LIPs are temporally associated with all of the major mass extinctions of the Phanerozoic (Bond and Grasby, 2017; Ernst and Youbi, 2017). The exact killing mechanism of a LIP remains controversial, and not all LIPs drive mass extinctions (Bond and Grasby, 2017). LIPs can impact global biogeochemical systems through, for example, emissions of greenhouse gases driving global warming and ocean acidification (Svensen et al, 2009) and halogens that deplete the ozone layer (Black et al, 2014), as well as an increased flux of toxic metals to the environment (Grasby et al, 2015). Most volcanically released metals are Inthemethylatedform,Hgisapotentn eurotoxin associated with behavioral, developmental, nephrological, reproductive, and endocrinological consequences (Eagles-Smith et al, 2018)
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