研究者詳細 - 北川　浩之

論文 - 北川　浩之

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*Radiocarbon concentration of lake sediment cellulose from Lake Erhai in southwest China 査読有り

H. Kitagawa, S. M. Tareq, H. Matsuzaki, N. Inoue, E. Tanoue and Y. Yasuda

Nucl. Instr. and Meth. in Phys. Res. B 259 巻頁： 526–529 2007年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

To improve age models for lake sediment cores without suitable 14C dating materials such as terrestrial plant fossils, we investigated the radiocarbon dating of lake sediment cellulose. The cellulose fraction in the sediments was obtained by a sequential decomposition of other organic matter, and subsequently dated by AMS. In general, 14C ages of the lake sediment cellulose obtained from a 10-m sediment core from Lake Erhai on the Yunnan-Guizhou Plateau are in agreement with 14C dates from terrestrial plant fossils. For the early Holocene, however, differences of up to 1000 14C years are observed between lake sediment cellulose and terrestrial plant fossils. This disagreement is probably caused by the contribution of 14C-depleted cellulose synthesized by aquatic plants/algae in the lake. To obtain a precise

Tropical South China Sea Surface 14C record in an annually-banded coral 査読有り

T. Mitsuguchi, Dang, X. Phong, H. Kitagawa, M. Yoneda and Y. Shibata

Radiocarbon 47 巻 ( 2 ) 2007年

Environmental Magnetic Record and Paleosecular Variation Data for the Last 40 Kyrs from Lake Biwa Sediments, Central Japan. 査読有り

A. Hayashida, M. Ali, Y. Kuniko, H. Kitagawa, M. Torii, K. Takemura

Earth, Planets and Space 59 巻頁： 807-814 2007年

Magnesium isotope analysis of different chlorophyll forms in marine phytoplankton using multi-collector ICP-MS 査読有り

K. Ra and H. Kitagawa

J. Anal. At. Spectrom. 22 巻頁： 817-821 2007年

記述言語：英語掲載種別：研究論文（学術雑誌）

A new separation method of magnesium in the different chlorophyll forms, including chlorophyll a, b, c1 + c2 and c3, of phytoplankton, was developed for isotope measurements. Our method is based on a two-step separation using HPLC and a C18 column. The method made it possible to determine the magnesium isotopes (d25Mg and d26Mg) of the particular chlorophyll forms in marine living phytoplankton with a high precision using a multi-collector ICP-MS. The differences of d26Mg values among commercial chlorophylls (four types of chlorophyll a and two types of chlorophyll b) and the different chlorophyll forms of marine diatom-rich phytoplankton collected from the Northwest Pacific show variations of 1.5% and 0.65%, respectively. We found a slight enrichment in the heavier magnesium isotopes in chlorophylls relative to sea-water: 0.58%, 0.74%, 0.27% and 0.35% on d26Mg for chlorophyll a, b, c1 + c2 and c3, respectively. Our data suggest a mass dependent fractionation of magnesium isotopes among species of photosynthetic organisms and the chlorophyll forms. The magnesium isotope analysis by chlorophyll forms might not only give a new insight into the biosynthetic pathways associated with chlorophylls but also be a potential environmental indicator preserved in marine phytoplankton and other photosynthetic organisms.

Variation of solar cyclicity during the Spoerer Minimum 査読有り

H. Miyahara, K. Masuda, Y. Muraki, H. Kitagawa and T. Nakamura

J. of Geophysical Research (Space Physics) 111 巻 ( A3 ) 頁： A03103 2006年3月

Sr/Ca ratio of Porites coral from Con Dao Island, South of Vietnam 査読有り

Dang, X. Phong, T. Mitsuguchi, H. Kitagawa, T. Uchida and Y. Shibata

Proc. of 10th Int'l Coral Reef Symposium 頁： 567-571 2006年

Seasonally specific responses of the East Asian monsoon to deglacial climate changes 査読有り

T. Nakagawa, P. E. Tarasov, H. Kitagawa, Y. Yasuda and K. Gotanda

Geology 34 巻 ( 7 ) 頁： 521-524 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）

The deglacial meltwater pulse in the North Atlantic that induced the Younger Dryas event also prompted climate cooling in East Asian monsoon regions such as Japan and coastal mid latitude China. However, very little is understood about the mechanism that can transmit changes in the North Atlantic to the Far East. Here we show that the shutdown of the North Atlantic thermohaline circulation brought about significantly lower temperatures and higher precipitation in the Japanese winter, whereas the change in the Japanese summer climate was considerably smaller. The cooling of the Siberian air mass seems to have caused an increased pressure gradient between Siberia and the West Pacific in winter, intensifying the winter monsoon. The Mongolian high pressure system and the westerly jet stream played an important role in the teleconnection. In contrast, the warming at the onset of the late glacial interstadial (GI-1; Bølling-Allerød) in the West Pacific did not have season-specific features, implying that the principal driving mechanism of this warming event may lie in a panhemispheric or global factor, such as insolation changes.

Seasonal changes of alkaline dust aerosol and its climatic influencing factors in western Songnen Plain, North-east China 査読有り

B. Chen, H, Ke, J. Dong-mei, H. Kitagawa and F. Li

Acta Scientiae Circumstantiae 26 巻 ( 3 ) 頁： 521-527 2006年

Late Quaternary faulting along the western margin of the Poronaysk Lowland in central Sakhalin, Russia 査読有り

H. Tsutsumi, Y. Suzuki, A. I. Kozhurin, M. I. Strel'tsov, T. Ueki, H. Goto, K. Okumura, R. F. Bulgakov and H. Kitagawa

Tectonophysics 407 巻頁： 257-268 2005年

Pollen/event stratigraphy of the varved sediment of Lake Suigetsu, central Japan from 15,701 to 10,217 SG vyr BP (Suigetsu varve years before present): Description, interpretation, and correlation with other regions 査読有り

T. Nakagawa, H. Kitagawa, Y. Yasuda, P. E. Tarasov, K. Gotanda and Y. Sawai

Quaternary Science Reviews 24 巻頁： 1691–1701 2005年

Eolian quartz flux variations in Cheju Island, Korea, during the last 6500 yr and a possible Sun–monsoon linkage 査読有り

J. Lim, E. Matsumoto and H. Kitagawa

Quaternary Research 64 巻頁： 12–20 2005年

韓国南東部・蔚山断層の古地　震活動－慶州市葛谷里における第2次トレンチ調査－査読有り

木康弘・岡田篤正・竹村恵二・慶　在福・廣内大助・金　幸隆・伊藤　愛・大石　超・中村洋介・成瀬敏郎・北川浩之・渡辺満久

活断層研究 25 巻頁： 147-152 2005年

Holocene evolution, of the outer lake of Hwajinpo Lagoon on the eastern coast of Korea; environmental changes with Holocene sea-level fluctuation of the East Sea (Sea of Japan)

J. G. Yum, K. M. Yu, K. Takemura, T. Naruse, A. Kitamura, H. Kitagawa and J. C. Kim

Radiocarbon 46 巻 ( 2 ) 頁： 797-808 2004年

The earliest record of major anthropogenic deforestation in the Ghab Valley, northwest Syria: a palynological study 査読有り

Y. Yasuda, H. Kitagawa and T. Nakagawa

Quaternary International 123/125 巻頁： 127-136 2004年

Radiocarbon contents in tree rings during the Sporer Minimum 査読有り

H. Miyahara, K. Masuda, Y. Muraki, T. Uemura, M. Kato, H. Toyoizumi, H. Furuzawa, T. Nakamura, H. Kitagawa and E. Matsumoto

Nucl. Instr. and Meth. in Phys. Res. B 233/224 巻頁： 655-659 2004年

High-resolution 14C analyses of annually-banded coral skeletons from Ishigaki Island, Japan: Implications for oceanography 査読有り

T. Mitsuguchi, H. Kitagawa, E. Matsumoto, Y. Shibata, M. Yoneda, T. Kobayashi, T. Uchida and N. Ahagon

Nucl. Instr. and Meth. in Phys. Res. B 223/224 巻頁： 455-459 2004年

Marin reservoir age in the south of Vietnam estimated from an annually-banded coral skeleton 査読有り

Dang X. Phong, T. Mitsuguchi, H. Kitagawa, Y. Shibata and T. Kobayashi

Radiocarbon 46 巻 ( 2 ) 頁： 657-660 2004年

Environmental archaeology at the Chengtoushan site, Hunan Province, China, and implications for environmental change and the rise and fall of the Yangtze River civilization 査読有り

Y. Yasuda, T. Fujiki, H. Nasu, M. Kato, Y. Morita, Y. Mori, M. Kanehara, S. Toyama, A. Yanoa, M. Okuno, H.

Quaternary International 123/125 巻頁： 149-158 2004年

Late-Holocene natural and anthropogenic vegetation changes in the Dongbei Pingyuan (Manchurian Plain), northeastern China 査読有り

M. Makohonienkoa, H. Kitagawa, T. Naruse, H. Nasu, A. Momohara, M. Okuno, T. Fujiki, X. Liug, Y. Yasuda and H. Ying

Quaternary International 123/125 巻頁： 71-88 2004年

Variation of the radiocarbon content of tree rings during the Spoerer Minimum 査読有り

H. Miyahara, K. Masuda, H. Furuzawa, Y. Muraki, T. Nakamura, H. Kitagawa and K. Arslanov:

Radiocarbon 46 巻 ( 2 ) 頁： 965-968 2004年

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