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Sueoka, Shigeru; Iwano, Hideki*; Danhara, Toru*; Niwa, Masakazu; Kanno, Mizuho; Kohn, B. P.*; Kawamura, Makoto; Yokoyama, Tatsunori; Kagami, Saya; Ogita, Yasuhiro; et al.
Earth, Planets and Space (Internet), 75(1), p.177_1 - 177_24, 2023/12
Times Cited Count：0 Percentile：0(Geosciences, Multidisciplinary)Fluid-inclusion and thermochronometric analyses have been applied to hydrothermal alteration zones and their host rocks outcropping in the Hongu area of the Kii Peninsula, southwestern Japan in an attempt to detect thermal anomalies related to hydrothermal events and quantify the thermal effects on the host rocks. Hydrothermal events at ca 150 deg. C and ca 200 deg. C were identified by fluid-inclusion microthermometry of quartz veins in the alteration zones. For the host rocks and alteration zones, in the youngest population zircon yielded U-Pb dates ranging between ca 74.7-59.2 Ma, fission-track dates of ca 27.2-16.6 Ma, and (U-Th)/He single-grain dates of ca 23.6-8.7 Ma. Apatite yielded pooled fission-track ages of ca 14.9-9.0 Ma. The zircon U-Pb dates constrain the maximum depositional ages of the sedimentary samples. However, the fission-track and (U-Th)/He dates show no clear trend as a function of distance from the alteration zones. Hence, no thermal anomaly was detected in the surrounding host rocks based on the thermochronometric data patterns. The fission-track and (U-Th)/He dates are rather thought to record regional thermal and exhumation histories rather than a direct thermal imprint of fluid flow, probably because the duration of such activity was too short or because fluid flow occurred before regional cooling events and were later thermally overprinted. Apatite fission-track ages of ca 10 Ma may reflect regional mountain uplift and exhumation related to the obduction of the SW Japan lithospheric sliver onto the Shikoku Basin, or the rapid subduction of the Philippine Sea slab associated with the clockwise rotation of the Southwest Japan Arc.
Fukuda, Shoma; Sueoka, Shigeru; Kanno, Mizuho; Kohn, B. P.*; Tagami, Takahiro*
Fisshion, Torakku Nyusureta, (34), p.9 - 13, 2021/12
In order to explore suitable zircon samples as standard minerals for the zircon (U-Th)/He (namely, ZHe) method, we have attempted to conduct ZHe analyses of the Nisatai dacite sampled in Iwate prefecture. Previous researches reported solid ages at 22-21 Ma and a rapid cooling pattern based on various geochronometric investigations, which inferred a potential of an age standard for ZHe method. Consequently, ZHe ages in this study yielded at 21.5 
0.2 Ma having wide dispersion of grain ages from 40 Ma to 15 Ma, probably caused by random errors. As possible causes of age dispersion, the zoning of parent nuclei in a crystal and the heterogeneous rock pieces revealed by observations of thin-section are considerable. Therefore, the Nisatai dacite was concluded as unsuitable sample for the ZHe age standard. However, geochronologic data of other methods showed comparable ages such as zircon fission-track and U-Pb method, the Nisatai dacite may be used as these age standards. We will continue to explore another candidates for ZHe age standard, e.g., U-Pb age standards.
Kanno, Mizuho; Sueoka, Shigeru; Fukuda, Shoma
JAEA-Testing 2020-010, 38 Pages, 2021/03
JAEA-Testing-2020-010.pdf:3.07MB
This report provides procedures of He measurement for (U-Th)/He dating at Tono Geoscience Center, Japan Atomic Energy Agency. (U-Th)/He method is a radiometric dating based on alpha decay of U and Th series isotopes, being utilized as a thermochronometer. (U-Th)/He thermochronometries on zircon and apatite are especially useful to estimate thermal history at low temperatures. The procedures are presented with the details, tips, and cautions because parts of the procedures can be carried out by beginners, including students and contractors. This report also includes some document formats helpful for conducting the procedures.
Sueoka, Shigeru; Shimada, Koji; Kanno, Mizuho; Yokoyama, Tatsunori
Fisshion, Torakku Nyusureta, (33), p.15 - 18, 2020/10
no abstracts in English
Sueoka, Shigeru; Shimada, Koji; Kanno, Mizuho; Yokoyama, Tatsunori
no journal, ,
no abstracts in English
Sueoka, Shigeru; Kanno, Mizuho; Kawamura, Makoto; Niwa, Masakazu; Iwano, Hideki*; Danhara, Toru*
no journal, ,
no abstracts in English
Fukuda, Shoma; Sueoka, Shigeru; Kanno, Mizuho; Kohn, B.*; Tagami, Takahiro*
no journal, ,
no abstracts in English
Tateishi, Ryo*; Shimada, Koji; Niwa, Masakazu; Sueoka, Shigeru; Shimizu, Mayuko; Kanno, Mizuho; Ishii, Chikako; Ishimaru, Tsuneari
no journal, ,
The major difference between active faults and inactive faults is the elapsed time after the latest activity, and while active faults are considered to be on the order of 
to 
years, inactive faults are over 
years. Therefore, even if the phenomena caused by fault activity are the same in both cases, the chemical changes that occur during the subsequent rest period of fault activity may differ significantly. In this study, the chemical composition of fault clay was collected by literature values and actual analysis, and the feasibility of discrimination by the chemical composition examined by linear discriminant analysis. According to the 11 elements selected based on the AIC, 45 active fault samples and 51 inactive fault samples were identified with a discrimination rate of 96%. Among the elements, TiO
and PO
tended to be concentrated as the latest activity period was newer. These concentration mechanisms are for future work.
Kanno, Mizuho; Niwa, Masakazu; Shimada, Koji; Tateishi, Ryo*
no journal, ,
It has been reported that there is a slight difference in the chemical composition of the whole rock between the fault gouge generated by fault activity and the uncrushed host rock. The reason for this is not clear, but since many fault gouges are rich in clay minerals, it is possible that the elements adsorbed on the surface of the clay minerals have some effect. Therefore, exchangeable cations were extracted by substituting cesium ions, which are easily adsorbed on the clay mineral surface, for the fault gaudis of active faults and inactive faults, and compared with the whole rock composition. A concentric logarithmic ratio transformation was used for the comparison. As a result, the concentration of inactive faults tended to be higher than that of active faults in Rb.
Tsukahara, Yuzuko; Kanno, Mizuho; Goto, Akira; Fujita, Natsuko; Komatsu, Tetsuya; Maemoku, Hideaki*
no journal, ,
Holocene crustal movements are recorded as fossil calcareous assemblages on rocky coast. It is possible to reconstruct crustal movements by summarizing these heights, structures and 
C ages. In this study, to clarify crustal movements, we collected calcareous assemblages and dated them using the C at Cape Hane. C ages show forming period of the lowest wave-cut-bench. However, it is difficult to determine the history of emerged events in a short cycle. To reconstruct the crustal movement history precisely, it is necessary to identify obvious multi-layer structures or discontinuous surfaces with time interval.
Ogata, Manabu; Tsukahara, Yuzuko; Kawamura, Makoto; Kanno, Mizuho; Nishiyama, Nariaki*; Sueoka, Shigeru; Komatsu, Tetsuya; Nakanishi, Toshimichi*; Yasue, Kenichi*
no journal, ,
Optically stimulated luminescence (OSL) dating method on feldspar is useful to date sediments on geomorphological time scale. In this presentation, we present the case studies for marine terraces in the Noto Peninsula and abandoned river valleys along the Oi River, for which the emergence ages were estimated by using feldspar OSL dating. This study was carried out as a part of the establishment of advanced technology for estimation of uplift rates using emergence ages of emergent landforms project.
Iwamori, Akiyuki*; Ogita, Yasuhiro; Shimada, Koji; Tateishi, Ryo*; Takagi, Hideo*; Ota, Toru*; Kanno, Mizuho*; Wada, Shinya*; Ono, Akihiro*; Otsuka, Yoshiharu*
no journal, ,
We investigated the W value, which is an index showing the progress of weathering, for the fault rocks in the Kojak granite distributed in the eastern Wakasa area. The W value represents the contribution due to weathering calculated from the chemical composition, and along with the M value (contribution of the mafic component) and F value (contribution of the felsic component), a triangular diagram of M + F + W = 100% showing trends from protolith to fault rocks (cataclasite or fault gouge) can be drown. We also investigated on the fault at the geological boundary between the Kojaku granite and the Mino-Tamba metabasalt, and on the difference in characteristics from the fault rock in the Kojaku granite. Granite protolith has an F value of 94.2% and W value of 4.9%, and the fault rock sample has an M value of about 3% regardless of whether it is an active fault or an inactive fault. As weathering progresses, the F value decreases and the W value increases. Metabasalt has an M value of 88.2% and a W value of 6.6%, and the cataclasite has an almost constant F value. As weathering progresses, the M value decreases and the W value increases. Some of the F value increases with the increase of the W value, which is consistent with the contamination of granite-origin quartz fragments found in the basaltic fault gouge. As a result of examination, it was confirmed that NaO and CaO have a great influence on the increase and decrease of the W value.
Tsukahara, Yuzuko; Ogata, Manabu; Kawamura, Makoto; Kanno, Mizuho*; Nishiyama, Nariaki; Sueoka, Shigeru; Nakanishi, Toshimichi*; Komatsu, Tetsuya
no journal, ,
One hundred thousand-year-scale uplift rate of the Japanese mountains is estimated mainly based on the Terrace to Terrace method (TT method; Yoshiyama and Yanagida, 1995). To apply the TT method, it is necessary to identify the pair of the sedimentary terraces of the last glacial period and the one before last glacial period. However, there are many mountains where such terrace pairs are not recognized. Therefore, as an alternative method to the TT method, we suggest the method based on landforms and deposits of incised meandering rivers (for example, Yasue et al., 2014; Ogata et al., 2021). In this presentation, we will report the results of a survey conducted in the middle of the Oi River as part of such research.
