Manning, Craig E., Shock, Everett, Sverjensky, Dimitri A., et al.
Carbon can be a major constituent of crustal and mantle uids, occurring both as dissolved ionic species (e.g., carbonate ions or organic acids) and molecular species (e.g., CO[subscript 2], CO, CH[subscript 4], and more complex organic compounds). The chemistry of dissolved carbon changes dramatically with pressure (P) and temperature (T). In aqueous uids at low P and T, molecular carbon gas species such as CO[subscript 2] and CH[subscript 4] saturate at low concentration to form a separate phase. With modest increases in P and T, these molecular species become fully miscible with H[subscript 2]O, enabling deep crustal and mantle uids ...