Effect of Pressure on Hydrogen Isotope Fractionation in Methane during Methane Hydrate Formation at Temperatures Below the Freezing Point of Water

Isotopic fractionation of methane between gas and solid hydrate phases provides data regarding hydrate-forming environments, but the effect pressure on isotopic is not well understood. In this study, hydrates were synthesized in a cell, hydrogen isotope compositions residual hydrate-bound gases determined. The δ2H formed below freezing point water was 5.7–10.3‰ lower than that methane, indicating generally encapsulates lighter molecules (CH4) instead CH32H. factors αH-V range 0.9881–0.9932 at temperature 223.3–268.2 K 1.7–19.5 MPa, respectively. Furthermore, increased with increasing formation pressure, suggesting difference isotopes surrounding yields pressure. Although differences observed study are insignificant, precise analyses natural same area enable determination during formation.