Anthropogenic-scale CO2 degassing from the Central Atlantic Magmatic Province as a driver of the end-Triassic mass extinction

Throughout Earth&#8217;s history, the coincidence in time between Large Igneous Province eruptions and mass extinctions points out a potential causality, where volcanic degassing may drive the global-scale climatic and environmental changes leading to biotic crises. The volcanic activity of the Central Atlantic Magmatic Province (CAMP, ca. 201 Ma), one of Earth&#8217;s most voluminous Large Igneous Provinces, is synchronous with the end-Triassic mass extinction event, among the most severe extinctions during the Phanerozoic. Combining different in situ analytical techniques (optical microscopy, confocal Raman microspectroscopy, EMP, SEM-EDS, and NanoSIMS analyses), bubble-bearing melt inclusions within basaltic rocks revealed the abundance of CO2 (up to 1.0 wt.%) in CAMP magmas [1]. Gaseous CO2&#160;and solid elemental C, alternatively preserved by gas exsolution bubbles within melt inclusions mainly hosted in clinopyroxene crystal clots, represent direct evidence for large amounts of volcanic CO2&#160;(up to 105&#8201;Gt) emitted into Earth&#8217;s surface during the entire CAMP activity [1]. The entrapment conditions of these melt inclusions within clinopyroxene aggregates constrain the degassed CO2 to a mantle and/or lower-middle crustal origin, indicating a deep source of carbon which may favour rapid and intense CAMP eruption pulses. Each magmatic pulse may have injected CO2 into the end-Triassic atmosphere in amounts similar to those projected for the anthropogenic emissions during the 21st century [1]. Therefore, volcanic CO2 degassed during CAMP eruptions likely contributed to end-Triassic global warming and ocean acidification with catastrophic consequences for the biosphere.&#160;[1] Capriolo et al. (2020),&#160;Nat. Commun.&#160;11,&#160;1670.

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Uppermost Triassic phosphorites from Williston Lake, Canada: link to fluctuating euxinic-anoxic conditions in northeastern Panthalassa before the end-Triassic mass extinction

Scientific Reports ◽

10.1038/s41598-019-55162-2 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Ekaterina Larina ◽

David J. Bottjer ◽

Frank A. Corsetti ◽

John-Paul Zonneveld ◽

Aaron J. Celestian ◽

...

Keyword(s):

Mass Extinction ◽

Regional Scale ◽

Broad Area ◽

Electron Microscopic ◽

Stressful Environment ◽

Central Atlantic Magmatic Province ◽

Minimum Zone ◽

Polyphosphate Metabolism ◽

Central Atlantic ◽

Oxygen Minimum

AbstractThe end-Triassic mass extinction (ETE) is associated with a rise in CO2 due to eruptions of the Central Atlantic Magmatic Province (CAMP), and had a particularly dramatic effect on the Modern Fauna, so an understanding of the conditions that led to the ETE has relevance to current rising CO2 levels. Here, we report multiple phosphorite deposits in strata that immediately precede the ETE at Williston Lake, Canada, which allow the paleoenvironmental conditions leading up to the mass extinction to be investigated. The predominance of phosphatic coated grains within phoshorites indicates reworking in shallow water environments. Raman spectroscopy reveals that the phosphorites contain organic carbon, and petrographic and scanning electron microscopic analyses reveal that the phosphorites contain putative microfossils, potentially suggesting microbial involvement in a direct or indirect way. Thus, we favor a mechanism of phosphogenesis that involves microbial polyphosphate metabolism in which phosphatic deposits typically form at the interface of euxinic/anoxic and oxic conditions. When combined with data from deeper water deposits (Kennecott Point) far to the southwest, it would appear a very broad area of northeastern Panthalassa experienced anoxic to euxinic bottom water conditions in the direct lead up to the end-Triassic mass extinction. Such a scenario implies expansion and shallowing of the oxygen minimum zone across a very broad area of northeastern Panthalassa, which potentially created a stressful environment for benthic metazoan communities. Studies of the pre-extinction interval from different sites across the globe are required to resolve the chronology and spatial distribution of processes that governed before the major environmental collapse that caused the ETE. Results from this study demonstrate that fluctuating anoxic and euxinic conditions could have been potentially responsible for reduced ecosystem stability before the onset of CAMP volcanism, at least at the regional scale.

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Two-pronged kill mechanism at the end-Triassic mass extinction

Geology ◽

10.1130/g49560.1 ◽

2022 ◽

Author(s):

Calum P. Fox ◽

Jessica H. Whiteside ◽

Paul E. Olsen ◽

Xingqian Cui ◽

Roger E. Summons ◽

...

Keyword(s):

Surface Waters ◽

Mass Extinction ◽

Global Scale ◽

Central Atlantic Magmatic Province ◽

Igneous Provinces ◽

Extinction Event ◽

Isotope Distributions ◽

Permian Mass Extinction ◽

Central Atlantic ◽

Camp Activity

High-resolution biomarker and compound-specific isotope distributions coupled with the degradation of calcareous fossil remnants reveal that intensive euxinia and decalcification (acidification) driven by Central Atlantic magmatic province (CAMP) activity formed a two-pronged kill mechanism at the end-Triassic mass extinction. In a newly proposed extinction interval for the basal Blue Lias Formation (Bristol Channel Basin, UK), biomarker distributions reveal an episode of persistent photic zone euxinia (PZE) that extended further upward into the surface waters. In the same interval, shelly taxa almost completely disappear. Beginning in the basal paper shales of the Blue Lias Formation, a Lilliput assemblage is preserved consisting of only rare calcitic oysters (Liostrea) and ghost fossils of decalcified aragonitic bivalves. The stressors of PZE and decalcification parsimoniously explain the extinction event and inform possible combined causes of other biotic crises linked to emplacement of large igneous provinces, notably the end-Permian mass extinction, when PZE occurred on a broad and perhaps global scale.

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