Globally enhanced mercury deposition during the end-Pliensbachian extinction and Toarcian OAE: A link to the Karoo–Ferrar Large Igneous Province

Percival, Lawrence; Witt, Melanie; Mather, Tamsin A.; Hermoso, Michaël; Jenkyns, Hugh C.; Hesselbo, Stephen P.; Suwaidi, Aisha Al; Storm, Marisa; Xu, Weimu; Ruhl, Micha

doi:10.1016/j.epsl.2015.06.064

Cited by 256 publications

(202 citation statements)

References 92 publications

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“…Several Phanerozoic events have previously been linked to approximately coeval LIPs through documented increases in sedimentary Hg concentrations, including the end-Permian and end-Cretaceous extinctions and Toarcian Oceanic Anoxic Event (e.g., refs. [26][27][28][29]. Importantly, sedimentary drawdown of Hg is typically achieved via organic matter (30,31), although sulphides and clays may also play a role (32)(33)(34).…”

Section: Significancementioning

confidence: 99%

Mercury evidence for pulsed volcanism during the end-Triassic mass extinction

Percival

Ruhl

Hesselbo

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

201

171

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The Central Atlantic Magmatic Province (CAMP) has long been proposed as having a causal relationship with the end-Triassic extinction event (∼201.5 Ma). In North America and northern Africa, CAMP is preserved as multiple basaltic units interbedded with uppermost Triassic to lowermost Jurassic sediments. However, it has been unclear whether this apparent pulsing was a local feature, or if pulses in the intensity of CAMP volcanism characterized the emplacement of the province as a whole. Here, six geographically widespread Triassic–Jurassic records, representing varied paleoenvironments, are analyzed for mercury (Hg) concentrations and Hg/total organic carbon (Hg/TOC) ratios. Volcanism is a major source of mercury to the modern environment. Clear increases in Hg and Hg/TOC are observed at the end-Triassic extinction horizon, confirming that a volcanically induced global Hg cycle perturbation occurred at that time. The established correlation between the extinction horizon and lowest CAMP basalts allows this sedimentary Hg excursion to be stratigraphically tied to a specific flood basalt unit, strengthening the case for volcanic Hg as the driver of sedimentary Hg/TOC spikes. Additional Hg/TOC peaks are also documented between the extinction horizon and the Triassic–Jurassic boundary (separated by ∼200 ky), supporting pulsatory intensity of CAMP volcanism across the entire province and providing direct evidence for episodic volatile release during the initial stages of CAMP emplacement. Pulsatory volcanism, and associated perturbations in the ocean–atmosphere system, likely had profound implications for the rate and magnitude of the end-Triassic mass extinction and subsequent biotic recovery.

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Section: Significancementioning

confidence: 99%

Mercury evidence for pulsed volcanism during the end-Triassic mass extinction

Percival

Ruhl

Hesselbo

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

201

171

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“…Its enrichments are used to trace increased volcanic activity in both proximal and distal sites, because of its emission in the form of gaseous elemental mercury (Hg 0 ), which is globally distributed due to a rather long atmospheric residence time (0.5–1 year)28. After oxidation to reactive Hg 2+ , Hg is deposited in continental and marine environments by precipitation29 (Fig. S1 in supplementary material).…”

mentioning

confidence: 99%

“…S1 in supplementary material). In sedimentary deposits, Hg is preferentially adsorbed onto organic matter, hydrous iron (Fe) oxides, and/or clay minerals2529303132 (Fig. S1 in supplementary material).…”

mentioning

confidence: 99%

“…The Hg, total organic carbon (TOC) and/or phyllosilicate and iron contents are therefore generally correlated in modern and ancient sediments29303132. Consequently, the origin of sedimentary Hg anomalies is evaluated by discrmining between enrichments related to enhanced TOC, iron, and/or clay mineral contents and enrichments related to volcanic activity29. In fact, since the pioneering work of Sanei et al 25,.…”

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confidence: 99%

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Mercury enrichment indicates volcanic triggering of Valanginian environmental change

Charbonnier

Morales

Duchamp‐Alphonse

et al. 2017

Sci Rep

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The Valanginian stage (Early Cretaceous) includes an episode of significant environmental changes, which are well defined by a positive δ13C excursion. This globally recorded excursion indicates important perturbations in the carbon cycle, which has tentatively been associated with a pulse in volcanic activity and the formation of the Paraná-Etendeka large igneous province (LIP). Uncertainties in existing age models preclude, however, its positive identification as a trigger of Valanginian environmental changes. Here we report that in Valanginian sediments recovered from a drill core in Wąwał (Polish Basin, Poland), and from outcrops in the Breggia Gorge (Lombardian Basin, southern Switzerland), and Orpierre and Angles (Vocontian Basin, SE France), intervals at or near the onset of the positive δ13C excursion are significantly enriched in mercury (Hg). The persistence of the Hg anomaly in Hg/TOC, Hg/phyllosilicate, and Hg/Fe ratios shows that organic-matter scavenging and/or adsorbtion onto clay minerals or hydrous iron oxides only played a limited role. Volcanic outgassing was most probably the primary source of the Hg enrichments, which demonstrate that an important magmatic pulse triggered the Valanginian environmental perturbations.

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“…Sanei et al 17 demonstrated that the Siberian Trap eruption, the largest LIP in the geologic record and also associated with the largest Phanerozoic extinction event, left a characteristic mercury spike as a fingerprint in the rock record. Subsequent work has confirmed Hg spikes associated with other LIP events associated with mass extinction intervals [18][19][20][21][22][23] . Grasby et al 21 also demonstrated that background Hg levels appear constant over geologic time, showing that Hg spikes associated with LIPs are truly anomalous features of the rock record.…”

Section: Mercury As a Proxy For Lip Eventsmentioning

confidence: 80%

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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Globally enhanced mercury deposition during the end-Pliensbachian extinction and Toarcian OAE: A link to the Karoo–Ferrar Large Igneous Province

Cited by 256 publications

References 92 publications

Mercury evidence for pulsed volcanism during the end-Triassic mass extinction

Mercury evidence for pulsed volcanism during the end-Triassic mass extinction

Mercury enrichment indicates volcanic triggering of Valanginian environmental change

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

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