Abiogenic Fischer-Tropsch synthesis of methane at the Baogutu reduced porphyry copper deposit, western Junggar, NW-China

Combining the results indicates that CO2 likely originated from the upper mantle with trace addition of sedimentary organic matter. During the uplift or emplacement of the granitoids, significant degassing caused the depletion of 13C and 2H. As the granitoids cooled, notable hydrothermal fluid boiling and water-rock interaction produced the depletion of 2H and 18O, respectively, and the magmatic CO2 was reduced to CH4 by Fischer-Tropsch type reactions that probably occurred during Ca-Na and potassic hydrothermal alteration.