The Ca and Mg isotope record of the Cryogenian Trezona carbon isotope excursion

Ahm, Anne-Sofie
Higgins, John A; ORCID: 0000-0002-4893-4561
The Trezona carbon isotope excursion is recorded on five different continents in platform carbonates deposited prior to the end-Cryogenian Marinoan glaciation (>635 Ma) and represents a change in carbon isotope values of 16–18‰. In this study, we combine calcium, magnesium, and strontium isotope geochemistry with a numerical model of carbonate diagenesis to disentangle the degree to which the Trezona excursion reflects changes in global seawater chemistry versus local shallow-water platform environments. Our analysis demonstrates that the most extreme carbon isotope values (∼-10‰ versus +10‰) are preserved in former platform aragonite that was neomorphosed to calcite during sediment-buffered conditions and record the primary carbon isotope composition of platform-top surface waters. We also find that the nadir of the Trezona excursion is associated with a fractional increase in siliciclastic sediments, whereas the recovery from the excursion correlates with a relative increase in carbonate.
How to cite this dataset:
Ahm, A., Higgins, J. A., 2022. The Ca and Mg isotope record of the Cryogenian Trezona carbon isotope excursion, Version 1.0. Interdisciplinary Earth Data Alliance (IEDA). Accessed 2024-05-21.
DOI Creation Date:
Ahm, A.-S.C., et al., The Ca and Mg isotope record of the Cryogenian Trezona carbon isotope excursion. Earth and Planetary Science Letters, 2021. 568: p. 117002.
Creative Commons Attribution-ShareAlike 4.0 International [CC-BY-SA-4.0]
Funding source(s):
National Science Foundation: 1654571
Coverage Scope: Regional (Continents, Oceans)
User Contributed Keyword(s):
calcium isotope, magnesium isotope, diagenesis, Snowball Earth
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