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Niwa, Masakazu; Mizuochi, Yukihiro*; Tanase, Atsushi*
Geofluids, 15(3), p.387 - 409, 2015/08
Times Cited Count：11 Percentile：50.67(Geochemistry & Geophysics)It is expected that in some cases water-rock interaction in fault zones can strongly affect nuclide migration. In this study, we analyzed the chemical composition of well-exposed fault rocks from the Atera Fault, Central Japan, to understand the variability and behavior of major and some selected trace elements. Hydrogen and oxygen isotope ratios in fault gouges, and carbon and oxygen isotope ratios in carbonates indicate that the two major clay-rich zones formed in bedrock at near surficial depth, consistent with observed deformation structures. Based on the analyses of chemical compositions, we identified depletion of SiO
, NaO, KO, and light rare earth elements associated with the formation of smectite and kaolinite, and increase of CaO, MnO, and heavy rare earth elements associated with carbonate precipitation caused by the mixing of allochthonous basalt fragments during fault activities.
Fukuda, Tetsuya*; Tanase, Atsushi*; Umeda, Koji; Kobayashi, Tetsuo*
Gekkan Chikyu, 37(5), p.197 - 203, 2015/05
no abstracts in English
Yasue, Kenichi; Takatori, Ryoichi*; Tanikawa, Shinichi*; Ninomiya, Atsushi*; Tanase, Atsushi*; Furusawa, Akira*; Tajikara, Masayoshi*
Chishitsugaku Zasshi, 120(12), p.435 - 445, 2014/12
Estimating the rate of change in landforms and geological environments due to erosion is important when assessing the safety of the geological disposal of high-level radioactive waste in Japan. The aim of this study is to develop an index of erosion rates in inland mountains. We focused on circular abandoned channels, which are old river valleys around detached meander cores formed by the cut-off of incised meandering rivers. The channels can be useful for estimating incision rates because they occur at a range of elevations throughout the Japanese Islands. We undertook a case study to determine the incision rate using a circular abandoned channel in the middle reaches of the Kumanogawa River in the Kii Peninsula, where many circular abandoned channels have been identified. We obtained undisturbed core samples of old river channel deposits and angular gravel deposits that overlie the circular abandoned channel. The old river channel deposits have been emergent since at least MIS5, based on an analysis of the soil color in angular gravel deposits. The incision rate, as calculated from this age and the difference in elevation between the abandoned and present channels, is less than about 0.9 m/ky. This study shows that analyses of circular abandoned channels can yield estimates of incision rates and potentially also uplift rates. More accurate estimates of incision rates require further studies of the dating and evolution of sediments that overlie circular abandoned channels.
Takatori, Ryoichi; Yasue, Kenichi; Tanikawa, Shinichi*; Ninomiya, Atsushi*; Tanase, Atsushi*
JAEA-Data/Code 2012-028, 15 Pages, 2013/03
JAEA-Data-Code-2012-028.pdf:34.12MB
JAEA-Data-Code-2012-028-appendix(CD-ROM).zip:0.52MB
To develop a method for estimating late Quaternary uplift rates of inland mountainous terrains where fluvial terraces are poorly developed, we focused on "circular abandoned channels", formed by meander cut-offs or river capture of an incised meandering river. We studied about 1,000 circular abandoned channels distributed throughout the Islands of Japan, and developed GIS database on circular abandoned channel in Japan. This database contains formation process, relative heights, degree of dissection and bedrocks of circular abandoned channels. Circular abandoned channels are distributed in inland mountainous terrains, where late Quaternary uplift rates are unknown, and indicate different relative heights along the same river. Relative heights tend to correlate with degree of dissection of the circular abandoned channels, which may indicate that degree of dissection correlate with ages of abandonment of circular abandoned channels.
Niwa, Masakazu; Mizuochi, Yukihiro*; Tanase, Atsushi*
Island Arc, 18(4), p.577 - 598, 2009/12
Times Cited Count：13 Percentile：10.09(Geosciences, Multidisciplinary)Architecture of fault/crush zones and their development histories are closely linked to the long-term stability of the underground environment. Herein, we studied part of the Atera Fault System, one of several large, active faults in Central Japan, and described the detailed mesoscopic and microscopic features of a crush zone to reveal its development at higher structural levels of the fault (i.e. several hundred meters to kilometers in depth). The zone is characterized by brittle fracturing and rock mass pulverization, lacks both ultracataclasite bands and any deformation structures showing pressure solution. The characteristics of the deformation structures suggest that the exposed crush zone was formed at a depth of less than several kilometers. Features of clay mineral and carbonate precipitations in the zone indicate the repetition of intense fragmentation and shear localization through periodic activities on the Atera Fault after the Pleistocene.
Tanase, Atsushi*; Oikawa, Teruki*; Ninomiya, Atsushi; Hayashi, Shintaro*; Umeda, Koji
Kazan, 52(1), p.39 - 61, 2007/02
Temporal and spatial variations on Plio-Pleistocene volcanism in the Ryohaku Mountains, central Japan, have been investigated by newly obtained K-Ar ages on 38 groundmass samples separated from volcanic rocks. The volcanoes in the Ryohaku Mountains form two volcanic rows of the Kuzuryu and hakusan Volcanic Chains which have ESE-WNW and N-S alignments, respectively. Early volcanic activity occurred intermittently from 3.6 Ma to 1.5 Ma, and the volcanoes near the junction of the two volcanic chains were active. The volcanic activity in the ESE-WNW trending Kuzuryu Volcanic Chain was restricted in the age range from 1.2 Ma to 0.7 Ma with migration from Eboshi-Washigatake Volcano (ESE end) to Hoonji Volcano (WNW end). The N-S trending Hakusan Volcanic Chain was active from 0.4 Ma to the present.
Tanase, Atsushi*; Chiba, Akihiko*; Takeda, Masahiro*
JNC TJ7420 2005-014, 210 Pages, 2004/03
JNC-TJ7420-2005-014.PDF:80.52MB
no abstracts in English
Tanase, Atsushi*; Chiba, Akihiko*; Takeda, Masahiro*
JNC TJ7420 2005-025, 316 Pages, 2003/03
no abstracts in English
Ishimaru, Tsunenori; Kakuta, Chifumi; Tanase, Atsushi*
JNC TN7420 2002-001, 43 Pages, 2002/07
JNC-TN7420-2002-001.pdf:0.37MB
A literature survey was carried out in order to understand the spatial and temporal distribution of the igneous activity of monogenetic volcanoes. The contents of the survey are as follows: (1)A review of the distribution, age and volcanic history of monogenetic volcanoes in Japan since 15Ma. (2)A review of the origin, lower crustal-upper mantle models and magma processes of monogenetic volcanoes in island arcs(Japan and overseas).
Tanase, Atsushi*; Uehara, Daijiro*; Ninomiya, Atsushi*
JNC TJ7420 2005-087, 365 Pages, 2002/03
JNC-TJ7420-2005-087.pdf:89.33MB
no abstracts in English
Tanase, Atsushi*
JNC TJ7420 2005-006, 168 Pages, 2002/03
JNC-TJ7420-2005-006.pdf:6.95MB
no abstracts in English
Tanase, Atsushi*
JNC TJ7420 2005-002, 179 Pages, 2001/02
JNC-TJ7420-2005-002.pdf:35.31MB
None
Tanase, Atsushi*
JNC TJ7420 2005-080, 542 Pages, 2000/03
JNC-TJ7420-2005-080.pdf:114.01MB
no abstracts in English
Tanase, Atsushi*
JNC TJ7420 2005-001, 657 Pages, 1998/12
JNC-TJ7420-2005-001.pdf:184.6MB
None
Tanase, Atsushi*
JNC TJ7420 2005-007, 544 Pages, 1998/03
no abstracts in English
Niwa, Masakazu; Nohara, Tsuyoshi; Mizuochi, Yukihiro*; Tanase, Atsushi*; Kobayashi, Hirohisa*
no journal, ,
The Atera Fault in the eastern part of Gifu Prefecture is a NW-trend active fault and shows sinistral strike-slip displacement. A fracture zone of the Atera Fault, in which granite (Naegi-Agematsu Granite) is in fault contact with welded tuff of the Nohi Rhyolite, is exposed several tens meters in width in Kawaue, Nakatsugawa City. Detailed occurrence of the fracture zone is described in this study to examine the research method to reveal histories of active faults. In the studied fracture zone, fault rocks of the welded tuff origin consist of fault breccia and clay, while those of the granite consist of cataclasite. The fault rocks of the welded tuff origin are more clay-rich than those of the granite origin. Textures of host rocks are more well-preserved in the fault rocks of the granite origin than in those of the the welded tuff origin.
Niwa, Masakazu; Mizuochi, Yukihiro*; Tanase, Atsushi*
no journal, ,
no abstracts in English
Niwa, Masakazu; Mizuochi, Yukiiro*; Tanase, Atsushi*
no journal, ,
no abstracts in English
Yasue, Kenichi; Tanikawa, Shinichi; Ninomiya, Atsushi*; Tanase, Atsushi*
no journal, ,
no abstracts in English
Niwa, Masakazu; Tanase, Atsushi*; Mizuochi, Yukihiro*; Kurosawa, Hideki
no journal, ,
no abstracts in English
