1990 Fiscal Year Final Research Report Summary
ESR Dating of Elephant Teeth
Project/Area Number |
01550042
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Research Category |
Grant-in-Aid for General Scientific Research (C)
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Allocation Type | Single-year Grants |
Research Field |
応用物理学一般(含航海学)
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Research Institution | Nagoya University |
Principal Investigator |
SOOCHONG Tai Nagoya University, Faculty of Nuclear Engineering, Associated Professor, 工学部, 教務職員 (60109296)
|
Co-Investigator(Kenkyū-buntansha) |
NAKASHIMA Yoshiyuki Nagoya University, Faculty of Nuclear Engineering, Associated Professor, 工学部, 助教授 (40023113)
|
Project Period (FY) |
1989 – 1990
|
Keywords | ESR / Dating / Elephant Teeth / Dose Rate / ^<60>Co / Gamma-ray spectroscopy / Radionuclide / Rad |
Research Abstract |
Chemical analysis of ^<238>U, ^<232>Th and ^<40>K in the dentine as well as enamel of elephant tooth fossil has been carried out in order to estimated the internal absorbed dose rate of the speciments, which was estimated to be (39<plus-minus>4)mrad/y on the assumption of early uptake model of radionuclides. The external radiation dose tate in the soil including the contribution from cosmic rays was also estimated to be (175<plus-minus>18)mrad/y with the help of gamma-ray spectroscopic techniques of the soil samples in which the specimens were buried. The ^<60>Co gammaray equivalent accumulated dose of (2<plus-minus>0.2)x10^4 rad for the tooth enamel gave "ESR age" of (9<plus-minus>2)x10^4 y, which falls in the geologically estimated range between 3x10^4 and 30x10^4 y before the present.
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