2014 Fiscal Year Annual Research Report
ＴＬ，ＯＳＬ，ＥＳＲによる百万年までのテフラの年代測定の比較的手法による確立
| Project/Area Number |
13F03325
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| Research Institution | Okayama University of Science |
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Principal Investigator |
豊田 新 岡山理科大学, 理学部, 教授 (40207650)
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| Co-Investigator(Kenkyū-buntansha) |
BISWAS Md Rabiul Haque 岡山理科大学, 理学部, 外国人特別研究員
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Keywords | dating / ESR / OSL / IRSL / tephra / quartz / feldspar |
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| Outline of Annual Research Achievements |
1. Dating of Japanese marker tephra using luminescence and ESR: We investigated three Japanese marker tephras, Ikeda-ko (6.4 ka), Aira-Tn (30 ka) and Aira-Iwato (45–50 ka). We could establish that post infrared- infrared stimulated luminescence signal (pIR-IRSL) of volcanic feldspar at elevated temperature has potential to date tephra up to ~400 ka. ESR ages were grossly correlated with the reference ages but large deviation and large associated errors are observed, possibly because of either low signal to noise ratio or heterogeneous dose response of different aliquot in multiple aliquot additive dose (MAAD) approach.
2. Band-tail states and anomalous fading of IRSL signal: Analysing museum and sedimentary K-feldspar we could understand the dependency of anomalous fading and band tail width which we observed non-Arrhenius are linked with degree of crystallinity of mineral.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
南九州の年代既知のテフラの分析が進んでおり、石英を用いたESR（電子スピン共鳴）年代と長石を用いたIRSL（赤外刺激発光）年代とで整合的な結果が得られた。
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| Strategy for Future Research Activity |
1. Testing the reliability of pIR-IRSL dating of tephra for older samples, up to 400 ka: Towards this we have collected tephra up to 120 ka from Hokkaido region and some more older samples will be collected to establish the new method to date quaternary tephra.
2. Dating of Kurobegawa granite using luminescence and ESR: Kurobegawa granites, the youngest granites in the world are dated as 0.5 to 10 Ma using K-Ar method and there is an indication of different thermal history. The same study will be performed using luminescence and ESR.
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