Carbonation by fluid--rock interactions at high-pressure conditions: implications for carbon cycling in subduction zones

Piccoli, Francesca; Brovarone, Alberto Vitale; Beyssac, Olivier; Martinez, Isabelle; Ague, Jay J; Chaduteau, Carine (2016). Carbonation by fluid--rock interactions at high-pressure conditions: implications for carbon cycling in subduction zones. Earth and planetary science letters, 445, pp. 146-159. Elsevier 10.1016/j.epsl.2016.03.045

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Carbonate-bearing lithologies are the main carbon carrier into subduction zones. Their evolution during metamorphism largely controls the fate of carbon, regulating its fluxes between shallow and deep reservoirs. Recent estimates predict that almost all subducted carbon is transferred into the crust and lithospheric mantle during subduction metamorphism via decarbonation and dissolution reactions at high-pressure conditions. Here we report the occurrence of eclogite-facies marbles associated with metasomatic systems in Alpine Corsica (France). The occurrence of these marbles along major fluid-conduits as well as textural, geochemical and isotopic data indicating fluid–mineral reactions are compelling evidence for the precipitation of these carbonate-rich assemblages from carbonic fluids during metamorphism. The discovery of metasomatic marbles brings new insights into the fate of carbonic fluids formed in subducting slabs. We infer that rock carbonation can occur at high-pressure conditions by either vein-injection or chemical replacement mechanisms. This indicates that carbonic fluids produced by decarbonation reactions and carbonate dissolution may not be directly transferred to the mantle wedge, but can interact with slab and mantle-forming rocks. Rock-carbonation by fluid–rock interactions may have an important impact on the residence time of carbon and oxygen in subduction zones and lithospheric mantle reservoirs as well as carbonate isotopic signatures in subduction zones. Furthermore, carbonation may modulate the emission of CO2 at volcanic arcs over geological time scales.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Institute of Geological Sciences > Rock-Water Interaction

UniBE Contributor:

Piccoli, Francesca

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0012-821X

Publisher:

Elsevier

Language:

English

Submitter:

Francesca Piccoli

Date Deposited:

11 Jun 2020 16:10

Last Modified:

11 Jun 2020 16:20

Publisher DOI:

10.1016/j.epsl.2016.03.045

BORIS DOI:

10.7892/boris.144414

URI:

https://boris.unibe.ch/id/eprint/144414

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