Carbonate dissolution during subduction revealed by diamond-bearing rocks from the Alps

.Carbon should therefore be retained in the slab and transportedto great depths in the mantle, rather than supply the arcvolcanoes. Here we identify diamonds in ultrahigh-pressurerocks from the Italian western Alps that have an oceanicorigin. We assess the geochemistry of diamond-bearing fluidinclusions and find that they contain bicarbonate, carbonateand sulphate ions, silica monomers, and crystals of carbonateand silicate. This fluid geochemistry...