Mercury evidence for pulsed volcanism during the end-Triassic mass extinction
Mercury evidence for pulsed volcanism during the end-Triassic mass extinction
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.
7929–7934
Percival, Lawrence M. E.
213ddd99-3fac-4b44-8632-5306c4bdb3dc
Ruhl, Micha
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Hesselbo, Stephen P.
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Jenkyns, Hugh C.
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Mather, Tamsin A.
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Whiteside, Jessica H.
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25 July 2017
Percival, Lawrence M. E.
213ddd99-3fac-4b44-8632-5306c4bdb3dc
Ruhl, Micha
c6ff3880-cfc4-4fc3-8150-c5fdc519ff30
Hesselbo, Stephen P.
bc7df614-e7f5-493a-9a80-643c506b5661
Jenkyns, Hugh C.
fff51099-4260-4b20-b72b-d5828994b2c5
Mather, Tamsin A.
fb84c181-8e26-47ac-9f7e-a4bd2d72bc8b
Whiteside, Jessica H.
5d9ad7aa-eba3-4ad9-9f6f-81be71b6829b
Percival, Lawrence M. E., Ruhl, Micha, Hesselbo, Stephen P., Jenkyns, Hugh C., Mather, Tamsin A. and Whiteside, Jessica H.
(2017)
Mercury evidence for pulsed volcanism during the end-Triassic mass extinction.
Proceedings of the National Academy of Sciences, 114 (30), .
(doi:10.1073/pnas.1705378114).
Abstract
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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Accepted/In Press date: 19 May 2017
e-pub ahead of print date: 19 June 2017
Published date: 25 July 2017
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Local EPrints ID: 412178
URI: http://eprints.soton.ac.uk/id/eprint/412178
ISSN: 0027-8424
PURE UUID: 4650a9c6-a8da-4afb-a4b2-8275d37bb5d4
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Date deposited: 13 Jul 2017 16:31
Last modified: 15 Mar 2024 15:14
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Author:
Lawrence M. E. Percival
Author:
Micha Ruhl
Author:
Stephen P. Hesselbo
Author:
Hugh C. Jenkyns
Author:
Tamsin A. Mather
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