Doubly substituted isotopologues of methane hydrate (13CH3D and 12CH2D2): Implications for methane clumped isotope effects, source apportionments and global hydrate reservoirs

Recently developed methane clumped isotope techniques provides fresh and novel insights into methane biogeochemistry, which have been unobtainable through other techniques such as conventional stable isotope determinations and molecular composition measurements of hydrocarbons. Nonetheless, the governing processes and mechanisms which control the clumped isotope signatures (Δ13CH3D and Δ12CH2D2) of natural methane samples remain an active area of investigation. Here, we present paired clumped isotope measurements in methane hydrate, which is a major methane reservoir widely distributed along the continental margins and which plays an important role in the global carbon cycle and climate system. Our study aims to shed new light into the fundamental processes of methane clumped isotope effects and their potential to answer fundamental questions regarding the source and migration of methane found in naturally occurring gas hydrate accumulations.