End-Triassic extinctions tied to Central Atlantic Magmatic Province eruption pulses

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Ben Creisler

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Oct 28, 2024, 5:07:31 PMOct 28
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Ben Creisler

A new paper:

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Dennis V. Kent, Paul E. Olsen, Huapei Wang, Morgan F. Schaller, and Mohammed Et-Touhami (2024)
Correlation of sub-centennial-scale pulses of initial Central Atlantic Magmatic Province lavas and the end-Triassic extinctions
Proceedings of the National Academy of Sciences 121(46): e2415486121
doi: https://doi.org/10.1073/pnas.2415486121
https://www.pnas.org/doi/10.1073/pnas.2415486121


Significance

During the initial phase of eruptions, Central Atlantic Magmatic Province (CAMP) basalts spewed more than 500 times the amount of sulfur released during the Laki historic eruption in Iceland. The repeated injections of sulfate aerosols, constrained by paleosecular variation data, occurred in rapid succession. The resulting severe [albedo-induced] volcanic winters may have been the proximal cause for the well-resolved end-Triassic mass extinction in the continental realm. However, in the less temporally constrained marine realm, longer-term cumulative release of carbon dioxide from CAMP eruptive and intrusive activity may have played an important albeit somewhat diachronous role in the extinctions through ocean acidification and longer-term warming.

Abstract

The end-Triassic extinction (ETE) on land was synchronous with the initial lavas of the Central Atlantic Magmatic Province (CAMP) and occurred just after the brief 26 thousand year (kyr) reverse geomagnetic polarity Chron E23r that can be used for global correlation. Lava-by-lava paleomagnetic secular variation data, previously reported from Morocco and northeastern United States combined with our data for the North Mountain Basalt from the Fundy Basin of Canada show that the initial phase of CAMP volcanism occurred in only five directional groups or pulses each occupying less than a century. The first four directional groups occur during a ~40 kyr period based on available astrochronology and U-Pb geochronology. The coincidence of the initial major pulse of CAMP volcanism with the ETE points to short-lived volcanic winters albedo-induced by sulfate aerosols as a plausible key agent of the extinctions in the tropical continental realm, whereas looser correlations allow prolonged CO2 emissions to contribute to more long-ranging effects in the marine realm via ocean acidification and longer-term warming.

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Dinosaurs thrived after ice, not fire, says a new study of ancient volcanism

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