2-3-1 構造I型結晶のメタン・エタン混合ガスハイドレートの解離時における構造II型結晶の二次生成(Session 2-3 ハイドレート物性I)

抄録

Methane and ethane mixed-gas hydrate composed of the cubic structure I and II has been discovered in a same sediment core retrieved from the mud volcanoes at Lake Baikal. We investigated the formation process of double structure gas hydrate in a laboratory experiment. The mixed-gas hydrates dissociated in a calorimeter showed two peaks in their thermograph, suggesting that a secondary formation of ethane-rich gas hydrate formed in their dissociation process. Isotopic fractionation of hydrogen isotope of hydrate-bound ethane was detected in the hydrate-bound gases between the first and second peaks, corresponded to the field data of the double structure observed at the Kukuy K-2 mud volcano (central Baikal Basin). These results supported an idea that the ethane-rich (structure II) gas hydrate formed after dissociation of methane-rich (structure I) gas hydrate.