2009 Fiscal Year Final Research Report
WEATHERING AND DENUDATION RATES OF LIMESTONES AND FORMATIVE PROCESSES OF KARST LANDFORMS
| Project/Area Number |
19300305
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geography
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| Research Institution | University of Tsukuba |
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Principal Investigator |
MATSUKURA Yukinori University of Tsukuba, 大学院・生命環境科学研究科, 教授 (80107341)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUZAKI Hiroyuki 東京大学, 大学院・工学研究科, 准教授 (60313194)
HATTANJI Tsuyoshi 筑波大学, 大学院・生命環境科学研究科, 講師 (00418625)
AOKI Hisashi 大東文化大学, 経営学部, 講師 (30423742)
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| Project Period (FY) |
2007 – 2009
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| Keywords | 地形 / 風化 |
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| Research Abstract |
This study attempted to quantify long-term subaerial denudation of bare carbonate rock surfaces by using in situ-produced cosmogenic ^<36>Cl in calcite. Carbonate samples were collected from the topmost 5cm of exposed pinnacles at several non-glaciated karst areas in subtropical to subarctic regions in Japan. Concentrations of natural Cl and ^<36>Cl in calcite were determined by accelerator mass spectrometry with isotope dilution with ^<35>Cl-enriched carrier spike. The nuclide concentrations were of the order of 10^5-10^6 atom g^<-1>, and converted to total denudation rates averaged over a 10^5 yr-timescale of chemical and physical processes acting on the karst surfaces. The denudation rates were 20-60mm kyr<-1>, being lowest in the central part of Japan. This tendency indicates the alternation of relative importance of chemical (dissolution) and physical (frost shattering) processes in denudation, depending on site-specific factors such as mean temperature, annual precipitation, and freeze-thawing intensity.
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[Journal Article] Denudation rates of carbonate pinnacles in Japanese karst areas : estimates from cosmogenic ^<36>Cl in calcite2010
Author(s)
Matsushi, Y., Sasa, K., Takahashi, T., Sueki, K., Nagashima, Y., Matsukura, Y.
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Journal Title
Nuclear Instruments and Methods in Physics Research B 268巻, Issues 7-8
Pages: 1205-1208
Peer Reviewed
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