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Journal Articles

Effects of buried environment on corrosion of iron artifacts excavated from Heijo Palace Site; Examination of the chloride salt accumulation inside of an iron artifact in soil

Yanagida, Akinobu*; Ura, Yoko*; Mitsui, Seiichiro; Ishidera, Takamitsu; Kawakita, Ryohei

Nara Bunkazai Kenkyujo Soritsu 70-Shunen Kinen Rombunshu; Bunkazai Ronso 5, p.843 - 856, 2023/03

To investigate chloride salt accumulation inside an iron artifact in soil, non-destructive analysis of three iron artifacts excavated from the Heijo Palace Site was conducted using elemental mapping by X-ray fluorescence analysis, micro-X-ray diffraction analysis, and X-ray computed tomography. Furthermore, the buried environments of the artifacts were presumed based on the previous reports of the environmental investigation at the Heijo Palace site. The results revealed the iron artifact's corrosion behavior was different individually- (1) the iron artifact that was presumed buried under oxidation environments had a goethite/magnetite corrosion layer and contained akageneite inside the corrosion layer. (2) the metal of the other iron artifacts buried under the oxidation environment had eluted absolutely and the artifacts had a rust layer formed by only goethite. (3) the other artifact buried in reduction environments had a rust layer composed of siderite. Accumulation of chloride salts inside an iron artifact was observed only in (1). Because each Cl $^{-}$ concentration measured in underground water observation holes at the Heijo Palace Site showed almost the same level concentrations, it was presumed that the accumulation of chloride salts depended on the environmental factor except for Cl $^{-}$ concentration. Based on these results, there was a possibility that the occurrence of local corrosion attributed to the separation of anodic and cathodic regions through the formation of the goethite/magnetite rust layer caused chloride salts accumulation inside an iron artifact.

Journal Articles

Fluvial terrace and geomorphology in the Tokigawa (Shonaigawa) river basin since the middle Pleistocene

Tajikara, Masayoshi*; Yasue, Kenichi; Yanagida, Makoto*; Furusawa, Akira*; Tanaka, Norifumi*; Morita, Yoshimune*; Sugai, Toshihiko

Chirigaku Hyoron, 84(2), p.118 - 130, 2011/03

https://doi.org/10.4157/grj.84.118

Many papers reported that Quaternary climate and sea-level fluctuations have controlled riverbed elevation in the river basins in the northeastern Japan. However, in the southwestern Japan, such climatic-controlled riverbed fluctuations have not been reported, except a few reports based on uncertain chronological data. In this research, we investigated fluvial terraces along the Tokigawa river that flows through the low relief mountainous areas, and examined whether riverbed fluctuations similar to these in rivers in the northeastern Japan occurred in the river basin. We mapped fluvial terraces based on air photo analysis, and inferred the age and climate at the time of formation of these terraces based on $^{14}$ C dating, tephra analysis, and pollen analysis. Based on results of these analyses, we concluded that the fluvial terraces in the river basin have been formed in consequence of the riverbed fluctuation linked to the climate change.

Journal Articles

Fluctuations of fossil pollen asseemblages from the Okute Basin, Mizunami City, Gifu Prefecture, Central Japan; Vegetation and climate records since marine isotope stage 9

Morita, Yoshimune*; Kamiya, Chiho*; Sasaki, Toshinori*; Miyagi, Toyohiko*; Sugai, Toshihiko; Yanagida, Makoto*; Furusawa, Akira*; Fujiwara, Osamu*

Kikan Chirigaku, 62(4), p.195 - 210, 2010/12

http://ci.nii.ac.jp/naid/40018701773

It is assumed that the variation of temperature and the precipitation with the climate change may affect geological environment such as the subsurface water flow. Therefore, as well as global climate change from the past to the present, investigation technology to grasp local climate change is indispensable. A palynological study was carried out using the sediment core taken from the Okute Basin, located in the northeast of Mizunami Underground Research Laboratory. As a result, it was appeared that in a interglacial epoch, there was much precipitation around this area, and that in a glacial epoch, became colder and more arid, compared with Kinki region in the same latitude. This shows that the modern analog method with pollen data from the sediment of the inland basin is effective technique to estimate a local climate change.

Journal Articles

Vegetation history since the middle Pleistocene in the middle-temperate zone of the Tokai district, Japan; A Palynological study of the small basin sediments

Morita, Yoshimune*; Kamiya, Chiho*; Sasaki, Toshinori*; Miyagi, Toyohiko*; Sugai, Toshihiko*; Yanagida, Makoto*; Furusawa, Akira*; Fujiwara, Osamu*; Moriya, Toshifumi*

Kikan Chirigaku, 58(3), p.123 - 139, 2006/00

https://doi.org/10.5190/tga.58.123

A palynological study was carried out using the 25.3 m long sediment core taken from Okute basin, Mizunami city, central Japan. Sediments of this core were accumilated for more than ca. 300,000 years. From the results of pollen analysis, the sediments are devided into 15 pollen assemblages zones. These changes show a repetition of five warm and four cool stages. Each stage corresponds to MIS 9 to 1. Consequently, a temperature of MIS 5 was higher than those of MIS 7 and 9. A temperature of MIS 9 was not so high.

JAEA Reports

None

Yanagida, Makoto*; Sasaki, Toshinori*; Sato, Ken*

JNC TJ7420 2005-104, 112 Pages, 2004/03

JNC-TJ7420-2005-104.pdf:19.77MB

no abstracts in English

JAEA Reports

Investigation of geomorphological diffusion coefficient of Japanese landform, 2

Yanagida, Makoto*; Sasaki, Toshinori*

JNC TJ7420 2005-057, 122 Pages, 2004/03

JNC-TJ7420-2005-057.pdf:46.07MB

None

JAEA Reports

Investigations of geomorphological diffusion coefficient of terrace scarps, 1

Yanagida, Makoto*; Sasaki, Toshinori*

JNC TJ7420 2005-046, 182 Pages, 2003/03

JNC-TJ7420-2005-046.pdf:70.88MB

None

JAEA Reports

Research of landslide topographical interpretation

Yanagida, Makoto*; Sasaki, Toshinori*

JNC TJ7420 2005-103, 58 Pages, 2002/03

JNC-TJ7420-2005-103.pdf:13.76MB

no abstracts in English

JAEA Reports

Investigations of geomorphological change speed in hill areas

Yanagida, Makoto*; Sasaki, Toshinori*

JNC TJ7420 2005-059, 352 Pages, 2002/03

JNC-TJ7420-2005-059.pdf:52.74MB

In order to evaluate how geological environment will be stability in the future, we estimated the change speed of the geomorphological process to be inputted into a computer model about geomorphological exchanges to an order in 100,000 years.

JAEA Reports