Abstract:
A global dataset of molecular and stable isotope compositions of hydrate-bound gases from 244 samples in 18 representative regions(including seas, inland seas and lakes, permafrost)is presented and discussed, during 1999-2011. The results indicate that Methane (C
1) is the most abundant hydrate-bound gas, while CO
2 and C
2 -C
6 hydrocarbon gases are frequently present in small amounts. Other gases, such as C
6+ and H
2S, are uncommon. The kinds of guest molecules in gas hydrates from seas, inland seas, lakes and permafrost were different, and the stable isotope composition (δ
13C and δD) of hydrate-bound gases varies significantly. In addition to the diagnosis of origins and sources of hydrate-bound gases, molecular and isotopic data can help to better study the control factors of formation and decomposition, and provide valuable insights into the gas migration and accumulation process of gas hydrate.