%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Lo Forte, F. M.
%A Schiavi, Federica
%A Rose-Koga, E. F.
%A Rotolo, S. G.
%A Verdier-Paoletti, M.
%A Aiuppa, A.
%A Zanon, V.
%T High CO2 in the mantle source of ocean island basanites
%D 2024
%L fdi:010089671
%G ENG
%J Geochimica et Cosmochimica Acta
%@ 0016-7037
%K Alkaline ocean islands ; Intraplate volcanism ; Fogo volcano ; Melt inclusions ; Cape Verde
%K CAP VERT ; ATLANTIQUE
%M ISI:001176581100001
%P 93-111
%R 10.1016/j.gca.2024.01.016
%U https://www.documentation.ird.fr/hor/fdi:010089671
%> https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2024-05/010089671.pdf
%V 368
%W Horizon (IRD)
%X Some of the most CO2-rich magmas on Earth are erupted by intraplate ocean island volcanoes. Here, we characterise olivine-hosted melt inclusions from recent (<10 ky) basanitic tephra erupted by Fogo, the only active volcano of the Cape Verde Archipelago in the eastern Atlantic Ocean. We determine H2O, S, Cl, F in glassy melt inclusions and recalculate the total (glass + shrinkage bubbles) CO2 budget by three independent methodologies. We find that the Fogo parental basanite, entrapped as melt inclusion in forsterite-rich (Fo80-85) olivines, contains up to -2.1 wt% CO2, 3-47 % of which is partitioned in the shrinkage bubbles. This CO2 content is among the highest ever measured in melt inclusions in OIBs. In combination with -2 wt% H2O content, our data constrain an entrapment pressure range for the most CO2-rich melt inclusion of 648-1430 MPa, with a most conservative estimate at 773-1020 MPa. Our results therefore suggest the parental Fogo melt is stored in the lithospheric mantle at minimum depths of -27 to -36 km, and then injected into a vertically stacked magma ponding system. Overall, our results corroborate previous indications for a CO2-rich nature of alkaline ocean island volcanism. We propose that the Fogo basanitic melt forms by low degrees of melting (F = 0.06-0.07) of a carbonenriched mantle source, containing up to 355-414 ppm C. If global OIB melts are dominantly as carbon-rich as our Fogo results suggest, then OIB volcanism may cumulatively outgas as high as -16-21 Tg of carbon yearly, hence substantially contributing to the global deep carbon cycle.
%$ 064 ; 066