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Journal Articles

Quantitative micro-X-ray fluorescence scanning spectroscopy of wet sediment based on the X-ray absorption and emission theories; Its application to freshwater lake sedimentary sequences

Katsuta, Nagayoshi*; Takano, Masao*; Sano, Naomi; Tani, Yukinori*; Ochiai, Shinya*; Naito, Sayuri*; Murakami, Takuma*; Niwa, Masakazu; Kawakami, Shinichi*

Sedimentology, 66(6), p.2490 - 2510, 2019/10

 Times Cited Count:2 Percentile:39.34(Geology)

Micro-X-ray fluorescence (XRF) scanning spectroscopy of marine and lake sedimentary sequences can provide detailed paleoenvironmental records available through element intensities proxy data. However, problems for effects of interstitial pore water on the micro-XRF intensities have been pointed out so far because of direct measurement on the split wet sediment surfaces. In this study, new methods for the XRF corrections were developed by being considered with the micro-X-ray scanning spectroscopy.

Journal Articles

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

 Times Cited Count:6 Percentile:46.34(Geography, Physical)

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.

Journal Articles

The Development of Fe-nodules surrounding biological material mediated by microorganisms

Yoshida, Hidekazu; Yamamoto, Koshi*; Amano, Yuki; Katsuta, Nagayoshi*; Hayashi, Toru*; Naganuma, Takeshi

Environmental Geology, 55(6), p.1363 - 1374, 2008/09

 Times Cited Count:8 Percentile:27.38(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.

Oral presentation

Continental response to millennial-scale climate change during the last glacial to Holocene period

Ikeda, Hisashi*; Shibata, Kenji; Murakami, Takuma; Kokubu, Yoko; Katsuta, Nagayoshi*

no journal, , 

no abstracts in English

Oral presentation

Late Holocene environmental changes in west Mongolia revealed by the lacustrine sediment analyses

Hayakawa, Tsubasa*; Katsuta, Nagayoshi*; Kokubu, Yoko; Hasebe, Noriko*; Murakami, Takuma; Miyata, Yoshiki*; Hasegawa, Hitoshi*; Nagao, Seiya*; Kawakami, Shinichi*

no journal, , 

no abstracts in English

Oral presentation

OSL and radiocarbon chronology of Late Quaternary sediments from Valley of the Gobi Lakes, Mongolia and implication to the glacier retreat in Khangai mountain range

Igarashi, Yudai*; Udaanjargal, U.*; Kokubu, Yoko; Watanabe, Takahiro; Hasegawa, Hitoshi*; Niiden, I.*; Katsuta, Nagayoshi*; Davaadorj, D.*; Hasebe, Noriko*

no journal, , 

Lake Olgoy locates in the "Valley of the Gobi lakes" in southern Mongolia, on the southern slope of Khangai Mountain range. The 10.5 m core was collected from Lake Olgoy in the winter of 2017. This study measured quartz OSL, feldspar IRSL and radiocarbon ages. Quartz OSL ages range in 0.6$$pm$$0.1 ka to 10.7$$pm$$2.5 ka, feldspar IRSL in 1.1$$pm$$0.1 ka to 52.9$$pm$$5.0 ka and radiocarbon ages in 1.4 ka to 48.6 ka. Based on the comparison of ages by three methods, the age-depth model of the core was proposed. Together with other analytical data from the core, glacier melting events in Khangai Mountains will be discussed.

Oral presentation

OSL, IRSL and radiocarbon chronology of Late Olgoi sediments, Mongolia, and implication to the glacier retreat events in Khangai mountain range

Igarashi, Yudai*; Udaanjargal, U.*; Kokubu, Yoko; Fujita, Natsuko; Hasegawa, Hitoshi*; Niiden, I.*; Katsuta, Nagayoshi*; Davaadorj, D.*; Hasebe, Noriko*

no journal, , 

Lake Olgoy locates in the "Valley of the Gobi lakes" in southern Mongolia, on the southern slope of Khangai Mountain range. The 10.5m core was collected from Lake Olgoy in the winter of 2017. This study measured quartz OSL, feldspar IRSL and radiocarbon ages. Quartz OSL ages range in 0.6$$pm$$0.1 ka to 10.7$$pm$$2.5 ka, feldspar IRSL in 1.1$$pm$$0.1 ka to 52.9$$pm$$5.0 ka and radiocarbon ages in 1.4 ka to 48.6 ka. Based on the comparison of ages by three methods, the age-depth model of the core was proposed. Together with other analytical data from the core, glacier melting events in Khangai Mountains will be discussed.

Oral presentation

Spherical concretion formation; Understandings and applications

Yoshida, Hidekazu*; Yamamoto, Koshi*; Maruyama, Ippei*; ASAHARA, Yoshihiro*; Minami, Masayo*; Sirono, Sinichi*; Hasegawa, Hitoshi*; Katsuta, Nagayoshi*; Nishimoto, Shoji*; Muramiya, Yusuke*; et al.

no journal, , 

no abstracts in English

Oral presentation

Environmental changes in paleo-dammed lake of Ane River in the mid-Holocene inferred from carbon, nitrogen, and sulfur isotopes

Masuki, Yuma*; Katsuta, Nagayoshi*; Niwa, Masakazu; Yoshimizu, Chikage*; Tayasu, Ichiro*

no journal, , 

In this presentation, we reported the results of stable carbon, nitrogen, and sulfur isotope analyses for lacustrine sediments formed by the sector-collapse in Mt. Ibuki, Shiga Prefecture.

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