Fossil biocalcite remains open to isotopic exchange with seawater for tens of millions of years
Détails
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Etat: Public
Version: Final published version
Licence: CC BY 4.0
Etat: Public
Version: Final published version
Licence: CC BY 4.0
ID Serval
serval:BIB_13DD1ABD0955
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Fossil biocalcite remains open to isotopic exchange with seawater for tens of millions of years
Périodique
Scientific Reports
Statut éditorial
Soumis à l'éditeur
Peer-reviewed
Oui
Volume
14
Pages
24933
Langue
anglais
Résumé
Fossilized remains of marine calcifiers constitute the physical basis for reconstructions of both deep ocean and sea-surface temperatures going back millions of years, but paleoclimate records derived from their isotope and trace-element chemistry can be biased by diagenesis. Experiments simulating diagenesis in the presence of an 18O-rich seawater analogue were conducted with modern and 14 Myr old foraminifera (Ammonia sp.) tests to investigate their relative susceptibility to oxygen isotope exchange. The fossilized tests were of exceptional preservation and similar to modern tests in terms of structure and crystalline organization, but had experienced partial loss of embedded organic structures, thus a priori offering fewer preferential pathways for porewaters to penetrate the tests. NanoSIMS imaging revealed that oxygen isotope exchange was pervasive in fossil tests, with isotopic exchange occurring at approximately half the rate of modern tests. The results unequivocally show that fossil biocalcites are metastable and remain more susceptible to isotope exchange than abiotic calcites millions of years after sedimentation and burial.
Mots-clé
Palaeoceanography, Palaeoclimate
Création de la notice
19/03/2024 16:12
Dernière modification de la notice
15/11/2024 20:28