Chemical weathering of the Himalayan river system in Bangladesh: a multi-isotope approach
| Project/Area Number |
16H05883
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| Research Category |
Grant-in-Aid for Young Scientists (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | Japan Agency for Marine-Earth Science and Technology (2017-2019)
The University of Tokyo (2016) |
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Principal Investigator |
YOSHIMURA Toshihiro 国立研究開発法人海洋研究開発機構, 海洋機能利用部門(生物地球化学プログラム), 研究員 (90710070)
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥24,700,000 (Direct Cost: ¥19,000,000、Indirect Cost: ¥5,700,000)
Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2018: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Fiscal Year 2017: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2016: ¥16,120,000 (Direct Cost: ¥12,400,000、Indirect Cost: ¥3,720,000)
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| Keywords | 化学風化 / ヒマラヤ / 同位体 / 氾濫原 / 削剥 / 河川 / 安定同位体比 / 風化 / 安定同位体 / 風化作用 |
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| Outline of Final Research Achievements |
This study investigated spatial isotopic variations of Sr, Li, Mg, Ca, O and H in dry- and wet-season river waters from the Ganges, Brahmaputra, and Meghna river system and groundwater in the Bengal Plain, Bangladesh. The sediment load in low-altitude plains is derived from rapid denudation of high mountains, where physical erosion rate is high and hence material is incompletely weathered (i.e., weathering-limited regime). The river samples collected in dry and wet seasons were within the analytical error of our analyses, thus indicating that relative inputs from the distinct the sources were effectively the same at a given sampling site. For the Bengal Plain, chemical weathering at greater sediment depths is more congruent. The Himalayan-derived material continue to be actively weathered during their transit through the floodplain, which is an important knowledge for climate-weathering feedback.
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| Academic Significance and Societal Importance of the Research Achievements |
ベンガル平野の河川水と地下水の同位体組成から、その溶質が上流の高山地帯からに由来するものではなく、多くは降雨と堆積物が反応することでもたらされたことが判明した。50m以深の地下水では化学組成がケイ酸塩鉱物の溶解反応の影響を多く受ける。本研究地域から海洋にもたらされる各種元素の同位体フラックスは非常に大きいため、長期的な海水の同位体組成に影響を及ぼす。地下水の同位体組成の平均値はガンジス・ブラマプトラ川の平均値と誤差の範囲で一致することから、化学風化が上流部と下流部で一致する定常状態にあることを示した。風化の気候影響を知る上で重要な知見である。
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Report
(5 results)
Research Products
(31 results)
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[Journal Article] Seasonal and spatial variations of chemical weathering in the Mekong basin: From the headwaters to the lower reaches2020
Author(s)
Kajita, H., Ota, Y., Yoshimura, Y., Araoka, D., Manaka, T., Ziyu, O., Iwasaki, S., Inamura, A., Uchida, E., Zheng, H., Yang, Q., Wang, K., Yanase, T., Suzuki, A., and Kawahata, H.
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Journal Title
Aquatic Geochemistry
Volume: －
Issue: 2
Pages: 1-23
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Journal Article] Partitioning and chemical environments of minor elements in individual large benthic foraminifera cultured in temperature-controlled tanks2019
Author(s)
Yoshimura, T., Maeda, A., Tamenori, Y., Suzuki, A., Fujita, K., Kawahata, H.
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Journal Title
Frontiers in Earth Science
Volume: 7
Pages: 124-124
DOI
Related Report
Peer Reviewed / Open Access
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[Journal Article] Altervalent substitution of sodium for calcium in biogenic calcite and aragonite2017
Author(s)
Yoshimura, T., Tamenori, Y., Suzuki, A., Kawahata, H., Iwasaki, N., Hasegawa, H., Nguyen, L.T., Kuroyanagi, A., Yamazaki, T., Kuroda, J., Ohkouchi, N.,
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Journal Title
Geochimica et Cosmochimica Acta
Volume: 202
Pages: 21-38
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Presentation] A change in the net carbonate input during the Quaternary desuced from the 88Sr/86Sr record2017
Author(s)
Yoshimura, T., Wakaki, S., Kuroda, J., Yamazaki, T., Iwasaki, S., Takagi, H., Kimoto, K., Sakuramoto, Y., Ishikawa, T. and Ohkouchi, N.
Organizer
ASLO 2017 Ocean Sciences Meeting
Place of Presentation
ホノルル市, ハワイ州, アメリカ合衆国
Year and Date
2017-02-26
Related Report
Int'l Joint Research
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[Presentation] δ26Mg of the chloropigments from oxygenic and anoxygenic phototrophic bacteria inside benthic microbial mat of the Trapani solar salterns (Italy)2017
Author(s)
Isaji, Y., Yoshimura, T., Araoka, D., Kuroda, J., Ogawa, N. O., Takano, Y., Jimenez-Espejo, F. J., Makabe, A., Suzuki, A., Shibuya, T., Lugli, S., Santulli, A., Manzi, V., Roveri, M., Kawahata, H. and Ohkouchi, N.
Organizer
ASLO 2017 Ocean Sciences Meeting
Place of Presentation
ホノルル市, ハワイ州, アメリカ合衆国
Year and Date
2017-02-26
Related Report
Int'l Joint Research
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[Presentation] A Quaternary 88Sr/86Sr record from planktonic foraminifera of Equatrial Pacific sediment2016
Author(s)
Yoshimura, T., Wakaki, S., Kuroda, J., Yamazaki, T., Iwasaki, S., Takagi, H., Kimoto, K., Sakuramoto, Y., Ishikawa, T. and Ohkouchi, N.
Organizer
Goldschmidt 2016
Place of Presentation
横浜市，神奈川県，日本
Year and Date
2016-06-26
Related Report
Int'l Joint Research
