Do mercury isotopes record the signature of massive volcanism in marine sedimentary records?

Thibodeau, Alyson M.; Bergquist, Bridget A.

doi:10.1130/focus012017.1

Cited by 63 publications

(56 citation statements)

References 20 publications

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“…Further tests of our hypothesis will be possible via tighter constraints on the geochronology of the Sturtian glaciation and the Franklin LIP, and better estimates of sulfur release with melt inclusion studies along with three‐dimensional coupled ocean‐atmosphere modeling of the climate effect of stratospheric aerosol emissions. Mercury anomalies have been observed in sedimentary records that span the Permian‐Triassic and Triassic‐Jurassic boundaries and have been attributed to the Siberian Traps and CAMP, respectively [ Thibodeau and Bergquist , , and references therein]. Our model predicts that similar mercury signals will be present in sedimentary successions deposited during onset of the Sturtian glaciation.…”

Section: Resultsmentioning

confidence: 99%

Initiation of Snowball Earth with volcanic sulfur aerosol emissions

Macdonald

Wordsworth

2017

Geophysical Research Letters

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We propose that the first Neoproterozoic Snowball Earth event, the Sturtian glaciation, was initiated by the injection of sulfate aerosols into the stratosphere. Geochronological data indicate that the Natkusiak magmatic assemblage of the Franklin large igneous province coincided with onset of the Sturtian glaciation. The Natkusiak was emplaced into an evaporite basin and entrained significant quantities of sulfur, which would have led to extensive SO2 and H2S outgassing in hot convective plumes. The largest of these plumes could have penetrated the tropopause, leading to stratospheric sulfate aerosol formation and an albedo increase sufficient to force a Snowball. Radiative forcing was maximized by the equatorial location of the Franklin and the cool Neoproterozoic background climate, which would have lowered the tropopause height, increasing the rate of stratospheric aerosol injection. Our results have implications for understanding Phanerozoic mass extinction events, exoplanet habitability, and aerosol perturbations to the present‐day climate.

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Section: Resultsmentioning

confidence: 99%

Initiation of Snowball Earth with volcanic sulfur aerosol emissions

Macdonald

Wordsworth

2017

Geophysical Research Letters

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“…The positive  199 Hg shift is consistent with increased direct atmospheric deposition of volcanically derived Hg 2+ to the ocean (Thibodeau and Bergquist, 2017). This shift also coincides with the reef demise, implying that onset of ELIP eruption, marked by increased Hg 2+ , may have caused reef development to cease through significant CO2 release triggering greenhouse warming, as seen in conodont oxygen isotopes record (Chen et al, 2011).…”

Section: Environment Perturbationsmentioning

confidence: 53%

“…DR4) suggests that the stratigraphic pattern of Hg concentration is not due to 176 variation in TOC content. With respect to Hg sources, volcanic Hg has insignificant MIF 177 ( 199 Hg 0 ‰) (Thibodeau and Bergquist, 2017). Once emitted to the environment, MIF 178 ( 199 Hg) mostly occurs and results in positive  199 Hg values (Blum et al, 2014).…”

Section: Environment Perturbationsmentioning

confidence: 99%

Biotic responses to volatile volcanism and environmental stresses over the Guadalupian-Lopingian (Permian) transition

Huang

Chen

Wignall

et al. 2018

Geology

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“…Mercury can undergo complex geochemical transformation processes in the environment, that may induce mass dependent fractionation (MDF) and mass independent fractionation (MIF) of Hg isotopes 25,45,46 . MDF can occur during various physical, chemical, or biological transformations of Hg, whereas MIF is generated through a more limited set of pathways (mostly photochemical), making it a more conservative tracer 46 . Generally, Hg derived from volcanic eruptions or geogenic sources has insignificant MIF (Δ 199 Hg ~ 0‰) with δ…”

Section: A Late Ordovician Lip Eventmentioning

confidence: 99%

“…When released to the environment, Hg cycles through the atmospheric, marine, and terrestrial reservoirs 46 . In the atmosphere, odd-isotope MIF can be generated through the aqueous photoreduction of Hg 2+ 48 , such as in surface waters and cloud droplets, resulting in excess odd-isotope (i. Hg values at two extinction levels are negligible, suggesting that the Hg spikes are not related to changes in the background Hg source, but rather just enhanced loading from those sources (volcanoes).…”

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confidence: 99%

Mercury Spikes Suggest Volcanic Driver of the Ordovician-Silurian Mass Extinction

Qing¹,

Zhao²,

Wang³

et al. 2017

Geological Society of America Abstracts With Programs

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The second largest Phanerozoic mass extinction occurred at the Ordovician-Silurian (O-S) boundary. However, unlike the other major mass extinction events, the driver for the O-S extinction remains uncertain. The abundance of mercury (Hg) and total organic carbon (TOC) of Ordovician and early Silurian marine sediments were analyzed from four sections (Huanghuachang, Chenjiahe, Wangjiawan and Dingjiapo) in the Yichang area, South China, as a test for evidence of massive volcanism associated with the O-S event. Our results indicate the Hg concentrations generally vary in parallel with TOC, and that the Hg/TOC ratios remain low and steady state through the Early and Middle Ordovician. However, Hg concentrations and the Hg/TOC ratio increased rapidly in the Late Katian, and have a second peak during the Late Hirnantian (Late Ordovician) that was temporally coincident with two main pulses of mass extinction. Hg isotope data display little to no variation associated with the Hg spikes during the extinction intervals, indicating that the observed Hg spikes are from a volcanic source. These results suggest intense volcanism occurred during the Late Ordovician, and as in other Phanerozoic extinctions, likely played an important role in the O-S event.Refinements in radio-isotopic dating techniques has demonstrated a strong temporal link between Large Igneous Province (LIP) volcanism and four out of the five largest mass extinctions in the Phanerozoic, leading to suggestions that LIP events have devastating effects on global ecosystems that in some ways mirrors concerns over modern anthropogenic impacts on the planet [1][2][3][4] . The one anomaly is the Ordovician-Silurian (O-S) mass extinction, the second largest of the "Big Five" extinctions. In terms of species loss the O-S represented about 86% of marine life 5,6 , including the elimination of graptolites 7-9 and brachiopods 10, 11 . The triggering mechanism of the O-S mass extinction has been extensively debated, and various hypotheses have been proposed, including gamma ray burst and bolide impact 12,13 ; however, the cause still remains highly controversial. Intense Late Ordovician volcanism was also suggested as a potential extinction mechanism 14,15 , although no clear geologic record of a Late Ordovician LIP event has been demonstrated. The age of the event makes it possible that any geologic record has been lost 15 . Given this, we tested for indirect evidence of volcanism at the O-S extinction boundary by examining the Hg record from classic sections in south China. Here we show that significant spikes in Hg concentrations occur at the O-S extinction, along with Hg stable isotope data that indicate a volcanic source for these spikes. We suggest that this reflects Hg loading by a LIP event. If correct, these results demonstrate that LIP events have indeed played a critical role in the evolution of life through time. Mercury as a Proxy for LIP eventsVolcanic eruptions are the main natural source of Hg to the environment 16 . Sanei et al. 17 demonstrated that th...

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Do mercury isotopes record the signature of massive volcanism in marine sedimentary records?

Abstract: Large Igneous Provinces (LIPs) are associated with a significant number of mass extinctions and ocean anoxic events (OAEs) during the Phanerozoic. However, the role of LIPs in triggering and sustaining biotic and environmental crises is controversial (e.g., Bond and Wignall, 2014).

Cited by 63 publications

References 20 publications

Initiation of Snowball Earth with volcanic sulfur aerosol emissions

Initiation of Snowball Earth with volcanic sulfur aerosol emissions

Biotic responses to volatile volcanism and environmental stresses over the Guadalupian-Lopingian (Permian) transition

Mercury Spikes Suggest Volcanic Driver of the Ordovician-Silurian Mass Extinction

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