2007 Fiscal Year Final Research Report Summary
Integrated chronology of the possible last-Interglacial marine terraces, southeast Shikoku Island, southwest Japan
| Project/Area Number |
18500789
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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 |
Geography
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| Research Institution | National Institute of Advanced Industrial Science and Technology |
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Principal Investigator |
UEKI Takeyuki National Institute of Advanced Industrial Science and Technology, Institute of Geology and Geoinformation, 研究員 (40371025)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAZAWA Tsutomu Institute of Geology and Geoinformation, 主任研究員 (50357620)
NAKASHIMA Rei Institute of Geology and Geoinformation, 研究員 (00392639)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Quaternary / Shikoku / marine terrace / chronology / paleomagnetism / bohore core / Pleistocene |
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| Research Abstract |
This study aims to construct a methodology to determine absolute age of Quatemary geomorphology and geology that lack a tephra bed. Integrated chronology including tephra correlation, paleomagnetic measurement, optically stimulated luminescence dating and various micro-fossil biostratigraphy were planed to apply the possible Last-Interglacial marine terraces distributed to the Tano Town, southeast Shikoku Island, southwest Japan. Fluvial sediments beneath the terraces buried a valley ; this stratigraphy suggests that the sediments were deposited during Oxygen Marine Isotope Stage 6 to 5e, and fine facies would contain a wide-spread tephra bed.
This study focuses on following three strategy. Valley-fill sediments were continuously sampled by borehole coring. In addition to tephra correlation, paleomagnetic measurement and optically stimulated luminescence dating were applied to core samples. Physical property measurements, facies analysis, chemical analysis, micro-fossil biostratigraphy, molluscan assemblage were combined to core samples.
Three coring were made for valley-fill sediments beneath the marine terraces. However, only one core contained valley-fill sediments and lacked a tephra bed. As a result, the ages of valley-fill sediments and overlying terraces were still unclear.
Paleomagnetic measurements were performed for drilled valley-fill sediments. Samples held a stable remanent magnetization with downward inclination, without 50 cm horizon range with upward or shallowly downward inclination. This exceptional inclination may result from geomagnetic excursion.
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