2001 Fiscal Year Final Research Report Summary
ENVIRONMENTAL VARIATION RECORDED IN STRAW STALACTITE
| Project/Area Number |
12680525
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | UNIVERSITY OF THE RYUKYUS |
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Principal Investigator |
TAIRA Hatsuo UNIVERSITY OF THE RYUKYUS, SCIENCE, PROFESSOR, 理学部, 教授 (70044998)
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| Co-Investigator(Kenkyū-buntansha) |
TANAHARA Akira UNIVERSITY OF THE RYUKYUS, INSTRUMENTAL RESEARCH CENTER, ASSOCIATED PROFESSOR, 機器分析センター, 助教授 (00217100)
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| Project Period (FY) |
2000 – 2001
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| Keywords | STRAW STALACTITE / SPELEOTHEM / STARAW STALACTITE / CAVE / RADON / CHEMICAL COMPOSITION / ENVIRONMENTAL VARIATIO / 洞窟 |
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| Research Abstract |
Straw stalactite in cave is generallry formed by decarbonization from droping water origined from ground water. Concrete straw is, however, generated by neutralization of Ca(OH)_2 in droping water with the absorption of carbon dioxide in atmosphere.
Differences on the growing process between natural carbonate such as coral and concrete straw are the following.
1. The gowth of concrete straw by the absorption of CO_2in atmosphere is rapid, whereas natural carbonates are gradually deposited。
2. Dropping water from concrete is to be Ca(OH)_2 alkaline solution (pH>12).
3. Chemical compositins of cave straw were different from concete straw showing higher Mg and Na<K.
4. Some cave straw show SC_4^<2-> in the matrix, however it was not found in concrete straw.
5. From the moniter of dropping waere for a year, small variation of Cl, Na, K and Mg, and large variation of NO_3^- and SO_4^<2-> were found.
6. The growth of concrete straw depends on the frequency of rain fall, but the lack in rain fall causes dehydration of the straw.
It was found that considerable amount of nitrate is corporated into concrete straw collected from Iriomote Island. It is well known, however, that nitrate is not to be incorporated in calcium carbonate. It is, therfore, interesting to study on the mechanisms of the formation of the concrete straw and the incorporation of nitrate into calcium carbonate.
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