CO2 outgassing during collisional orogeny is facilitated by the generation of immiscible fluids

Abstract Orogenic degassing is emerging as a potentially relevant source of carbon dioxide (CO 2 ) from the continental crust. However, processes mobilization are still poorly explored. Here, we use thermodynamic modeling to investigate decarbonation sediments metamorphosed under high geothermal gradients. Our shows that immiscible CO -rich vapors and hydrosaline brines generated at these conditions, with different properties mobility through The fluid fraction could rapidly rise toward surface without interacting host rocks by carbo-fracturing or deep faults. denser likely permeate rocks. When applied active Himalayan orogen, observations reconcile measured fluxes positive conductivity anomalies associated micro-seismicity depth. crust represents reservoir can be efficiently degassed during hot collisions.