Fossil biocalcite remains open to isotopic exchange with seawater for tens of millions of years

Details

Serval ID
serval:BIB_13DD1ABD0955
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Fossil biocalcite remains open to isotopic exchange with seawater for tens of millions of years
Journal
Scientific Reports
Author(s)
Cisneros-Lazaro Deyanira, Adams Arthur, Stolarski Jarosław, Bernard Sylvain, Daval Damien, Baronnet Alain, Grauby Olivier, Baumgartner Lukas P., Vennemann Torsten, Moore Jo, Baumgartner Claudia, Martin Olmos Cristina, Escrig Stéphane, Meibom Anders
Publication state
Submitted to the publisher
Peer-reviewed
Oui
Language
english
Abstract
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.
Create date
19/03/2024 16:12
Last modification date
08/11/2024 18:56
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