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Marine Strontium Isotope Evolution at the Triassic-Jurassic Transition Links Transient Changes in Continental Weathering to Volcanism of the Central Atlantic Magmatic Province
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  • Bernát Heszler,
  • Joachim A. R. Katchinoff,
  • Laszlo Palcsu,
  • Anikó Horváth,
  • Zsolt Vallner,
  • Emma Blanka Kovács,
  • Noah Planavsky,
  • József Pálfy
Bernát Heszler
School of Earth Sciences, University of Bristol
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Joachim A. R. Katchinoff
Yale University
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Laszlo Palcsu
Isotope Climatology and Environmental Research Centre, Institute for Nuclear Research
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Anikó Horváth
Isotope Climatology and Environmental Research Centre, Institute for Nuclear Research
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Zsolt Vallner
Department of Geology, Institute of Geography and Earth Sciences, Eötvös Lóránd University
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Emma Blanka Kovács
Trinity College Dublin, The University of Dublin
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Noah Planavsky
Yale
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József Pálfy
Eötvös Loránd University

Corresponding Author:[email protected]

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Abstract

The end-Triassic extinction (ETE) is one of the most severe biotic crises in the Phanerozoic. This event was synchronous with volcanism of the Central Atlantic Magmatic Province (CAMP), the ultimate cause of the extinction and related environmental perturbations. However, the continental weathering response to CAMP-induced warming remains poorly constrained. Strontium isotope stratigraphy is a powerful correlation tool that can also provide insights into the changes in weathering regime but the scarcity of 87Sr/86Sr data across the Triassic-Jurassic boundary (TJB) compromised the use of this method. Here we present new high-resolution 87Sr/86Sr data from bulk carbonates in Csővár, a continuous marine section that spans 2.5 Myrs across the TJB. We document a continuing decrease in 87Sr/86Sr the from the late Rhaetian to the ETE, terminated by a 300 kyr interval of no trend and followed by a transient increase in the early Hettangian that levels off. We suggest that the first in the series of perturbations is linked to the influx of non-radiogenic Sr from the weathering of freshly erupted CAMP basalts, leading to a delay in the radiogenic continental weathering response. The subsequent rise in 87Sr/86Sr after the TJB is explained by intensified continental crustal weathering from elevated CO2 levels and reduced mantle-derived Sr flux. Using Sr flux modeling, we also find support for such multiphase, prolonged continental weathering scenario. Aggregating the new dataset with published records employing an astrochronological age model results in a highly resolved Sr isotope reference curve for an 8.5 Myr interval around the TJB.
23 Jan 2024Submitted to ESS Open Archive
24 Jan 2024Published in ESS Open Archive
Mar 2024Published in Geochemistry, Geophysics, Geosystems volume 25 issue 3. 10.1029/2024GC011464