Formation process of swamp sediments of the Karako Lowland in northern Shimabara Peninsula, Western Japan

Nakanishi, Toshimichi*; Okuno, Mitsuru*; Yamasaki, Keiji*; Hong, W.*; Fujita, Natsuko; Nakamura, Toshio*; Horikawa, Yoshiyuki*; Sato, Eiichi*; Kimura, Haruo*; Tsutsumi, Hiroyuki*

Nagoya Daigaku Nendai Sokutei Kenkyu, 5, p.38 - 43, 2021/03

no abstracts in English

A Geochemical approach for identifying marine incursions; Implications for tsunami geology on the Pacific coast of northeast Japan

Watanabe, Takahiro; Tsuchiya, Noriyoshi*; Yamasaki, Shinichi*; Sawai, Yuki*; Hosoda, Norihiro*; Nara, Fumiko*; Nakamura, Toshio*; Komai, Takeshi*

Applied Geochemistry, 118, p.104644_1 - 104644_11, 2020/07

https://doi.org/10.1016/j.apgeochem.2020.104644

Possible tsunami inundation areas can be predicted from the distribution of paleo tsunami deposits, which are mainly composed of marine-derived sands and muds on land. Such exotic sandy and muddy layers have been identified by multiple approaches. However, there still remain uncertainties and other useful proxies need to be investigated for the identification of tsunami deposits. Here we show the geochemical signatures of modern tsunami deposits from the Pacific coast of Northeast Japan (2011 Tohoku tsunami), as well as those paleo tsunami deposits, which were taken from the Tohoku District (Jogan, ca. 1080 calibrated ages before present [cal BP] and Yayoi, ca. 2000 cal BP). A geochemical ternary diagram (Seawater-Rock-(As+Metals)) enables the weathering trend of tsunami deposits over ca. 2000 years in the Sendai Plain in the Tohoku to be shown. In the paleo tsunami layers from the Tohoku, the Na/Ti atomic ratios markedly increased to 23.4, and the average values were 19.33.0 (Jogan and Yayoi tsunami deposits), which were clearly higher than those of other layers (soil deposits, 10.33.5 on average). These results show that the Na/Ti ratio is a useful indicator of marine incursions in our case. Our rapid and simple method using the Na/Ti ratio can be easily applied to the Tohoku, and it may contribute to the detection of unrecorded muddy tsunami deposits.

C ages and calendar years of Japanese nails measured with accelerator mass spectrometry

Nagata, Kazahiro*; Furunushi, Yasuko*; Matsubara, Akihiro*; Kokubu, Yoko; Nakamura, Toshio*

Tetsu To Hagane, 105(4), p.488 - 491, 2019/04

https://doi.org/10.2355/tetsutohagane.TETSU-2018-137

The Japanese nails had been produced by the traditional ironmaking way of Tatara until the Edo period since the late of 6 Century. The quality of the Japanese nails is affected from steel produced by Tatara in each age. The C ages of 3 Japanese nails collected at shrines and temples at their repair were measured with accelerator mass spectrometry and calibrated to calendar years. Each C age provided plural calendar year periods with definite probabilities, and one of the periods determined in comparison with the history of temples and their repair records. The production ages of nails used in the Daibutuden of the Todaiji temple, the living quarters of the Manjuin temple and the Zaoudo of the Yoshino-Kongoji temple are before 1692, the 12 Century and before 1592, respectively, when they were repaired or reconstructed.

Hydrological and climate changes in southeast Siberia over the last 33 kyr

Katsuta, Nagayoshi*; Ikeda, Hisashi*; Shibata, Kenji*; Kokubu, Yoko; Murakami, Takuma*; Tani, Yukinori*; Takano, Masao*; Nakamura, Toshio*; Tanaka, Atsushi*; Naito, Sayuri*; et al.

Global and Planetary Change, 164, p.11 - 26, 2018/05

https://doi.org/10.1016/j.gloplacha.2018.02.012

Paleoenvironmental and paleoclimate changes in Siberia were reconstructed by continuous, high-resolution records of chemical compositions from a sediment core retrieved from the Buguldeika Saddle, Lake Baikal, dating back to the last 33 cal. ka BP. The Holocene climate followed by a shift at ca. 6.5 cal. ka BP toward warm and dry, suggesting that the climate system transition from the glacial to interglacial state occurred. In the last glacial period, the deposition of carbonate mud from the Primorsky Range was associated with Heinrich events (H3 and H1) and the Selenga River inflow was caused by meltwater of mountain glaciers in the Khamar-Daban Range. The anoxic bottom-water during Allerod-Younger Dryas was probably a result of weakened ventilation associated with reduced Selenga River inflow and microbial decomposition of organic matters from the Primorsky Range. The rapid decline in precipitation during the early Holocene may have been a response to the 8.2 ka cooling event.

AMS radiocarbon dates of pyroclastic-flow deposits on the southern slope of the Kuju Volcanic Group, Kyushu, Japan

Okuno, Mitsuru*; Nagaoka, Shinji*; Kokubu, Yoko; Nakamura, Toshio*; Kobayashi, Tetsuo*

Radiocarbon, 59(2), p.483 - 488, 2017/00

https://doi.org/10.1017/RDC.2016.66

We present here results of AMS C dating to refine the history of the middle and western parts of the Kuju Volcanic Group, located in middle Kyushu, Japan, which consists of more than 20 lava domes and cones. C dating has conducted by AMS (JAEA-AMS-TONO) under the Common-Use Facility Program of JAEA. The Handa PF deposits, which are products of the largest eruption of the group, were dated to 53.5 ka BP. The Shirani and Muro PF deposits, which are block-and-ash flows, were dated to 44 to 50 cal ka BP and 3539 cal ka BP, respectively. These ages can be correlated with the TL ages for the lava domes. Therefore, both TL and C methods can be useful tools in establishing the eruptive sequence of lava domes and pyroclastic flows. This study also demonstrates that these eruptive activities occurred after the Handa pfl, the biggest eruption during the last 150 kyrs without a significant time interval.

RICE-W (Radiocarbon Intercomparison on Chemical Experiments, Water series) program; An Examination of the precipitation method

Minami, Masayo*; Takahashi, Hiroshi*; Aramaki, Takafumi*; Kokubu, Yoko; Ito, Shigeru*; Nakamura, Toshio*

Nagoya Daigaku Kasokuki Shitsuryo Bunsekikei Gyoseki Hokokusho, 26, p.132 - 137, 2015/03

http://www.nendai.nagoya-u.ac.jp/ja/tande_report/2014/minami132%202014.pdf

We have started a Radiocarbon Intercomparison on Chemical Experiments, Water series (RICE-W) program to examine whether carbon isotopic fractionation and carbon contamination occur or not on C analysis of dissolved inorganic carbon (DIC) in water by different sample preparation and storage methods. Eight water samples of four kinds (surface seawater, ground water, hot spring water, and sodium bicarbonate solution) have already analyzed by six AMS laboratories in Japan, and the results obtained are gradually being published. Here, we report the progress of RICE-W program briefly, and then give consideration to the result using the precipitation method, by which DIC is precipitated into SrCO or BaCO, and then oxidized with HPO to extract CO.

AMS radiocarbon dating of wood trunks in the pumiceous deposits of the Kikai-Akahoya eruption in Yakushima Island, SW Japan

Okuno, Mitsuru*; Nakamura, Toshio*; Geshi, Nobuo*; Kimura, Katsuhiko*; Kokubu, Yoko; Kobayashi, Tetsuo*

Nuclear Instruments and Methods in Physics Research B, 294, p.602 - 605, 2013/01

https://doi.org/10.1016/j.nimb.2012.05.015

We found numerous wood trunks from pumiceous deposits along Nagata, Isso and Miyanoura rivers on the northern side of Yakushima Island, 60 km south of Kyushu Island, and conducted radiocarbon dating using accelerator mass spectrometry (AMS). The obtained C dates were around 6500 BP, and geological characteristics of the pumiceous deposits indicate that these specimens were buried during the Kikai-Akahoya (K-Ah) eruption from the Kikai caldera. However, they are not charred, suggesting that the origin of these deposits is not of pyroclastic flow but that of tsunami. Fourteen taxa were identified through anatomical characteristics. This is the first discovery on species of the forest of the Yakushima Island before the devastating eruption.

An Inter-laboratory comparison study on C measurements between two AMS laboratories of Nagoya University and JAEA Mutsu

Nakamura, Toshio*; Tanaka, Takayuki; Kabuto, Shoji; Ota, Tomoko*

Nagoya Daigaku Kasokuki Shitsuryo Bunsekikei Gyoseki Hokokusho, 21, p.159 - 165, 2010/03

http://www.nendai.nagoya-u.ac.jp/ja/tande_report/2009/nakamura%20mutsu2009.pdf

An inter-laboratory comparison of C dating studies with AMS were performed between Nagoya University and JAEA. Two kinds of archeological samples used for the intercomparison were offered from the Education Board of Nirasaki city. One part of them was a charred rice sample with known historical age, which was collected from the ruin of Shimpu-Jo castle remains. The rice was charred when the castle was burnt in 1582, when the castle was abandoned by Katsuyori Takeda during the battle against the combined military forces of Oda and Tokugawa families. The other samples were charred pyrenes of peach and nutshells of Japanese walnut collected from the Shukujiri-Daini-Iseki archeological site. The results from the two AMS laboratories were quite consistent within statistical uncertainties. In addition, calibrated C ages for the charred rice samples were also consistent with the historical age when the Shimpu-Jo castle was burnt down.

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

Study on operation conditions and an operation system of a nuclear powered submersible research vessel; Report of working group on application of a very small nuclear reactor to an ocean research

Ura, Tamaki*; Takamasa, Tomoji*; Nishimura, Hajime*; Aoki, Taro*; Ueno, Michio*; Maeda, Toshio*; Nakamura, Masato*; Shimazu, Shunsuke*; Tokunaga, Sango*; Shibata, Yozo*; et al.

JAERI-Tech 2001-049, 154 Pages, 2001/07

JAERI-Tech-2001-049.pdf:11.24MB

JAERI has studied on design and operation of a nuclear powered submersible research vessel, which will navigate under sea in the Arctic Ocean, as a part of the design study of advanced marine reactors. This report describes operation conditions and an operating system of the vessel those were discussed by the specialists of hull design, sound positioning, ship motions and oceanography, etc. The design conditions on ship motions for submersible vessels were surveyed considering regulations in our country, and ship motions were evaluated assuming the observation activities in the Arctic Ocean. A submarine transponder system and an on ice communication buoy system were examined as a positioning and communication system supposing the activity under ice. Procedures to secure safety of nuclear powered submersible research vessel were discussed based on the investigation of accidents. These results were reflected to the concept of the nuclear powered submersible research vessel, and subjects fto be settled in the next step were clarified.