1IPGP - Institut de Physique du Globe de Paris (IPGP, 1 rue Jussieu, 75238 Paris cedex 05 ; Université Paris Diderot, Bât. Lamarck A case postale 7011, 75205 Paris CEDEX 13 - France)
Abstract : The origin of carbonatites-igneous rocks with more than 50% of carbonate minerals-and whether they originate from a primary mantle source or from recycling of surface materials are still debated. Calcium isotopes have the potential to resolve the origin of carbonatites, since marine carbonates are enriched in the lighter isotopes of Ca compared to the mantle. Here, we report the Ca isotopic compositions for 74 carbonatites and associated silicate rocks from continental and oceanic settings, spanning from 3 billion years ago to the present day, together with 0 and C isotopic ratios for 37 samples. Calcium-, Mg-, and Fe-rich carbonatites have isotopically lighter Ca than mantle-derived rocks such as basalts and fall within the range of isotopically light Ca from ancient marine carbonates. This signature reflects the composition of the source, which is isotopically light and is consistent with recycling of surface carbonate materials into the mantle
https://hal-insu.archives-ouvertes.fr/insu-02916256 Contributor : Eva FareauConnect in order to contact the contributor Submitted on : Tuesday, August 18, 2020 - 8:21:50 AM Last modification on : Wednesday, May 11, 2022 - 10:00:05 AM Long-term archiving on: : Tuesday, December 1, 2020 - 7:13:49 PM
Elsa Amsellem, Frédéric Moynier, Hervé Bertrand, Amaury Bouyon, João Mata, et al.. Calcium isotopic evidence for the mantle sources of carbonatites. Science Advances , American Association for the Advancement of Science (AAAS), 2020, 6 (23), pp.eaba3269. ⟨10.1126/sciadv.aba3269⟩. ⟨insu-02916256⟩