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Yoshida, Hidekazu; Yamamoto, Koshi*; Amano, Yuki; Katsuta, Nagayoshi*; Hayashi, Toru*; Naganuma, Takeshi
Environmental Geology, 55(6), p.1363 - 1374, 2008/09
Times Cited Count：9 Percentile：26.69(Environmental Sciences)Takashikozo is a phenomenon of Quaternary sediments in Japan. They are cylindrical Fe-oxyhydroxide nodules that form as plaques round plant roots. Structural features suggest that after the roots have decayed, the central space where the roots were situated acts as a flow path for oxidized water. Analysis of microbial 16S rDNA extracted from the nodules identified iron-oxidizing bacteria encrusted round the roots where they are the likely initiators of nodule formation. Geological history and nanofossil evidence suggest that these Fe-nodules may have been buried at a depth of up to several tens of meters for a least 100000 years in reducing Quaternary sediments. Thus Fe-oxyhydroxide nodules with water and rock by microbial mediation can persist under reducing conditions. The phenomenon is significant as an analogue of post-closure conditions in radioactive waste repositories, since it could influence nuclide migration.
Yoshida, Hidekazu; Metcalfe, R.*; Yamamoto, Koshi*; Amano, Yuki; Hoshii, Daisuke*; Kanekiyo, Akiko*; Naganuma, Takeshi*; Hayashi, Toru*
Applied Geochemistry, 23(8), p.2364 - 2381, 2008/08
Times Cited Count：9 Percentile：26.07(Geochemistry & Geophysics)Subsurface redox fronts control the mobilization and fixation of many trace elements. Any safety assessment for a deep geological repository for radioactive wastes needs to take into account adequately the long-term redox processes in the geosphere surrounding the repository. The water-rock-microbe interactions can be considered analogous to the processes occurring in the redox fronts that would develop around geological repositories for radioactive waste. Once formed, the Fe-ooxyhydroxides within such a front would be preserved even after reducing conditions resume following repository closure.
Chen, X.*; Chikamatsu, Kentaro*; Nagata, Mitsuhiro; Yokoyama, Tatsunori; Kagami, Saya; Yamamoto, Koshi*; Oto, Shigeru*
no journal, ,
no abstracts in English
Yoshida, Hidekazu*; Yamamoto, Koshi*; Maruyama, Ippei*; Asahara, Yoshihiro*; Minami, Masayo*; Shirono, Shinichi*; Hasegawa, Hitoshi*; Katsuta, Nagayoshi*; Nishimoto, Shoji*; Muramiya, Yusuke*; et al.
no journal, ,
no abstracts in English
Yoshida, Hidekazu*; Yamamoto, Koshi*; Maruyama, Ippei*; Karukaya, Koichi*; Nakayama, Masashi; Sakurai, Akitaka; Sato, Toshinori
no journal, ,
Spherical, isolated carbonate concretions occur throughout the world in marine argillaceous sedimentary rocks of widely varying geological ages. These concretions are characteristically highly enriched in CaCO
compared to the surrounding sedimentary rock matrices and are commonly containing the well-preserved fossils inside. Recently the process of the enrichment of CaCO has been revealed and synthetic concretion materials are developed. Here we will introduce the in-situ experiment with the synthetic concretion material for EDZ sealing carried out in Horonobe Underground Research Laboratory and the preliminary results of the EDZ sealing process and their sealing effectiveness.
Yoshida, Hidekazu*; Yamamoto, Koshi*; Karukaya, Koichi*; Matsui, Hiroya
no journal, ,
no abstracts in English
Yoshida, Hidekazu*; Yamamoto, Koshi*; Asahara, Yoshihiro*; Karukaya, Koichi*; Saito, Akane*; Matsui, Hiroya
no journal, ,
no abstracts in English
Yoshida, Hidekazu*; Yamamoto, Koshi*; Asahara, Yoshihiro*; Karukaya, Koichi*; Matsui, Hiroya; Metcalfe, R.*
no journal, ,
The ability of synthetic concretion-forming solvents to seal groundwater flow-paths by rapid precipitation of CaCO in bed rock flow-paths has been tested by an in-situ experiment in the underground research laboratory (URL) located in Horonobe, northern Hokkaido, Japan. The experiment showed a decrease in permeability to as low as 1/100 to 1/1,000 of the initial permeability over a period of one year. This sealing process can be applied to various activities that require long-term containment of materials underground, for example abandonment of boreholes connected with hydrocarbon extraction, or CO
injection, or sealing of facilities for geological disposal of nuclear wastes.
Yoshida, Hidekazu*; Yamamoto, Koshi*; Asahara, Yoshihiro*; Karukaya, Koichi*; Saito, Akane*; Matsui, Hiroya; Mochizuki, Akihito
no journal, ,
The report are the results of the in situ experiment for sealing to underground cavities by a synthetic concretion-forming solvent and observed phenomenon of the sealing function after a earthquake.
Yoshida, Hidekazu*; Yamamoto, Koshi*; Asahara, Yoshihiro*; Karukaya, Koichi*; Saito, Akane*; Matsui, Hiroya; Mochizuki, Akihito
no journal, ,
This report summarized the latest results of in-situ feasibility experiment for self-sealing process of EDZ and flow-paths factures in Horonobe URL of JAEA and calsite crystallization induced by concretion-forming solvent injection was observed on the fracture surface in EDZ.
