@misc{oai:repo.qst.go.jp:00059967,
 author = {Fehn, Udo and Snyder, G. and Muramatsu, Yasuyuki and 村松 康行},
 month = {Sep},
 note = {The large-scale occurrence of gas hydrates in marine sediments has attracted increased attention over the last decade, but the origin of methane remains a major open question associated with these hydrocarbons.  Iodine is a strongly biophilic element and has one long-lived cosmogenic isotope, 129I.  The half-life of this isotope is 15.7 Ma, giving it a dating range of about 80 Ma.  A strong enrichment of iodine (and, to a lesser degree, of bromine) has been observed in pore waters associated with gas hydrates, which suggests that the 129I system can be used for the dating of iodine in these fluids.   We report here new results from two ODP legs, Peru Margin (ODP 201) and Hydrate Ridge (ODP 204) and compare them to earlier investigations of pore fluids collected from the hydrate field at the Nankai Trough (Fehn et al., 2003), and from Blake Ridge, ODP 164 (Fehn et al., 2000). In all of these cases, ages found for the iodine in the pore waters are considerably older than the ages of the sediments hosting the pore waters and the gas hydrates.  Most of the ages range between 25 and 55 Ma, in some cases giving quite uniform ages for a set of samples (i.e. Blake Ridge), while showing considerable variation in other cases.  The results suggest that iodine and, by association, methane is not derived in-situ, but from organic material much older than the host sediments.  The distribution of isotopic values in specific cases reflects the history of advection and mixing between advected and resident iodine., 第13回 Goldschmidt 2003},
 title = {On the origin of marinegas hydrates: Systematics of iodine and I-129 in pore waters},
 year = {2003}
}