1994 Fiscal Year Final Research Report Summary
Detection of uranium fission tracks in minerals using tandem accelerator and its application to paleo-geothermal history analysis
| Project/Area Number |
05452090
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
WATANABE Koichiro Faculty of Erg., Kyushu Univ., Assoc.Prof., 工学部, 助教授 (10182916)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Tandem accelerator / Fission track / Paleo-geothermalactivity / Thermal history analysis / Geochronology |
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| Research Abstract |
1. Field survey and sampling were performed in the paleo-geothermal area. Investigated areas are (1) paleo-geothermal field in Goto-Fukue island, (2) hydrothermal alteration zone in Yamaguni-Onta area in Oita Pref., (3) Kunisaki-Bajyo gold field in Oita Pref. (4) Nansastu and Hokusatsu gold fields in Kagoshima Pref. (5) Hasami gold field in Nagasaki Pref.and Arita porcelain clay deposit in Saga Pref. (6) Unzen geothermal field in Nagasaki Pref. (7) Hoshino gold field in Fukuoka Pref. (8) Taio gold field in Oita Pref.XRD study clarified hydrothermal alteration zoning in each study field. Then fission track age of zircon and apatite, K-Ar age of biotite and hornblende and thermoluminescence age of quartz were determined for rock samples. Host rocKs or altered rocks in such areas indicated ages of middle Miocene to late Pleistocene.
2. Zircon and apatite were mounted in tefron disk and irradiated with heavy ion at a tandem accelerator in Kyushu University. Beam energy was 80-95 MeV,and ion flux was controlled with Rutherford scattering with Au foil. After irradiation, sample was chemically etched, and then confined fission tracks of uranium intersecting heavy ion tracks were detected successfully. Ni is convenient to generate heavy ions. Silicon semi-conductor detector is useful to control fluence of ion beam.
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