@misc{oai:repo.qst.go.jp:00071605,
 author = {Fujiwara, Taisei and Toyoda, Shin and Uchida, Ai and Ishibashi, Jun-Ichiro and Nakai, Shun'ichi and Takamasa, Asako and 賞雅 朝子},
 month = {Jun},
 note = {ESR (electron spin resonance) dating method has been
applied to calcite, aragonite, hydroxyapatite, quartz and
gypsum. Recently it was shown that this method is also
practically applicable to barite, especially those in sea-floor
hydrothermal sulfide deposits (Takamasa et al., 2013).
ESR, 226Ra-
210Pb, and 228Ra-
228Th ages were determined for
barite crystals extracted from hydrothermal sulfide deposits
taken at hydrothermal fields at the Okinawa Trough. The ages
range 4.1 to 16000 years where the ages obtained by the three
methods coincide in some of the samples while the 228Ra-
228Th
ages are the youngest and ESR ages, the oldest and the 226Ra- 210Pb ages in between in the other samples. The samples with
younger ESR ages show younger 226Ra-
210Pb ages and those
with older ESR ages show older 226Ra-
210Pb ages with no
detection of 228Ra. The inconsistency of the ages between these
methods would be explained by the mixture of the barite
crystals with younger and older ages, formed by several
hydrothermal activities. The order of ages of the 5
hydrothermal fields would be arranged, from young to old as
follows; Yoron Hole field, Daiyon-Yonaguni Knoll field,
Hatoma Knoll field, being nearly equal to Iheya North Knoll
field．, Goldschmidt2014},
 title = {ESR, 226Ra-210Pb and 228Ra-228Th Dating of Barite in Sea-Floor Hydrothermal Sulfide Deposits in the Okinawa Trough},
 year = {2014}
}