Acta Medica Okayama 83 4 2003 Sulphur-isotopic composition of the deep-sea mussel Bathymodiolus marisindicus from currently active hydrothermal vents in the Indian Ocean 841 848 EN Toshiro Yamanaka Chitoshi Mizota Yoshihiro Fujiwara Hitoshi Chiba Jun Hashimoto Toshitaka Gamo Takamoto Okudaira <p>Sulphur-isotopic composition of soft tissues from bathymodiolus marisindicus collected from hydrothermal vents in the indian ocean was reported. the [delta]³⁴s values of the soft tissues (+3[similar]+5‰ vs cañyon diablo troilite) were nearly identical to those from the associated hydrothermal fluid and chimney sulphides (+5 to +8‰), but were significantly different from that of the common seawater sulphate (+21‰), which suggested that the endosymbiotic bacteria used sulphide in the fluid as an energy source. transmission electron microscopic observation of the endosymbionts also suggested that the symbiont is a thioautotroph. bathymodiolus species, which depend on either sulphide or methane oxidation, or both, have a worldwide distribution. bathymodiolus marisindicus from the indian ocean has a close relationship with congeners in the pacific ocean as evidenced by form of symbiosis. biogeography and migration of the genus bathymodiolus based on the relevant data are briefly discussed.</p> No potential conflict of interest relevant to this article was reported.

岡山大学温泉研究所 Acta Medica Okayama 0369-7142 56 1985 水試料の敢素同位体比の自動測定 27 34 EN Hitoshi Chiba Hitoshi Sakai Masatoshi Yasutake 10.18926/21085 The automatic sample preparation system for oxygen isotope analysis of natural water samples was constructed. The system is essentially a modification of that originally designed by W. Dansgaard in the University of Copenhagen. Sixty water samples of 5 ml each are automatically equilibrated with CO(2) of 30 ml NTP each within 4.5 hours. The equilibrated CO(2) gases are successively measured for their oxygen isotopic ratios by an automatic mas-sspectrometer, VG903. The time required for the measurement of the 60 CO(2) samples is about 15 hours; thus approximately 20 hours are required to complete the isotopic measurements of 60 water samples. The accuracy of the oxygen isotopic analyses is about 0.1%. The result of oxygen isotopic analyses by the automatic preparation system agrees with that of the conventional method within about +0.1%. The results indicate that the automatic preparation system is applicable for the oxygen isotope analysis of natural water samples. No potential conflict of interest relevant to this article was reported.

岡山大学理学部地球科学教室 Acta Medica Okayama 1340-7414 12 1 2005 Tin-bearing chalcopyrite and platinum-bearing bismuthinite in the active Tiger chimney, Yonaguni Knoll IV seafloor hydrothermal system, South Okinawa Trough, Japan 1 5 EN Kaul Gena Hiroshi Chiba Katsuo Kase 10.18926/ESR/13850 The active sulfide chimney ore sampled from the flank of the active Tiger chimney in the Yonaguni Knoll IV hydrothermal system, South Okinawa Trough, consists of anhydrite, pyrite, shalerite, galena, chalcopyrite and bismuthinite. Electron microprobe analyses indicated that the chalcopyrite and bismuthinite contain up to 2.4 wt. % Sn and 1.7 wt. % Pt, respectively. The high Sn-bearing chalcopyrite and Pt-bearing bismuthinite are the first occurrence of such minerals on the submarine hydrothermal systems so far reported. The results confirm that the Sn enters the chalcopyrite as a solid solution towards stannite by the coupled substitution of Sn 4+ Fe 2+ for Fe 3+ Fe 3+ while Pt enters the bismuthinite structure as a solid solution during rapid growth. The homogenization temperature of the fluid inclusions in anhydrite (220-310℃) and metasured end-member temperature of the vent fluids (325℃) indicate that the minerals are precipitated as metastable phases at temperature around 300℃. The Sn-bearing chalcopyrite and Pt-bearing bismuthinite expess the original composition of the minerals deposited from a hydrothermal fluid with temperatures of about 300℃. No potential conflict of interest relevant to this article was reported.