Gas Hydrate and Water Isotope Anomalies

The water sequestered in the hydrate lattice is preferentially enriched in 0 and deuterium (D), thus the isotopic composition of the water in the pore spaces collected from gas hydrate bearing sediment can provide additional information on the abundance and the characteristics of these deposits. Pore fluid samples that had been modified by hydrate decomposition upon core recovery during ODP Legs 146 (Kastner et al. 1998), and 164 (Matsumoto and Borowski 2000) provided the first field data to derive the oxygen isotope fractionation factor for in situ hydrate formation. A more comprehensive sampling 

C/ and Cl-g are the Cf concentrations of sampled and formation water (i.e., in situ interstitial water) determined as background, respectively. The fraetionation factors for oxygen (a ) and hydrogen (a ) eanbe determined from equilibrium equation, sueh that  

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