Carbon-saturated COH fluids in the upper mantle: a review of high-pressure and high-temperature ex situ experiments

Abstract. High-pressure COH fluids have a fundamental role in variety of geological processes. Their composition terms volatile species can control the solidus temperature and carbonation/decarbonation reactions, as well influence amount solutes generated during fluid–rock interaction at depth. Over last decades, several systems been experimentally investigated to unravel effect upper-mantle conditions. However, fluid is rarely tackled quantitative issue, rather infrequently are analyzed same way associated solid phases experimental assemblage. A comprehensive characterization carbon-bearing aqueous hampered by difficulties synthetizing analyzing high-pressure without altering their upon quenching. Recently, improved techniques proposed for analyses carbon-saturated fluids, leading significant advancement synthetic characterization. Here, we present review experiments conducted lower-crust P–T (pressure temperature) conditions, which characterized quantitatively through ex situ techniques. We background most commonly employed thermodynamic models together with synthetize them analyze when coexists phases. highlight how approach step understand these conditions provide strong foundation ultimately deep cycling elements.