2000 Fiscal Year Final Research Report Summary
Formation ages of elevated peneplains of the Japanese Islands-An approach from the fission-track dating.
| Project/Area Number |
10440144
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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 |
Geology
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| Research Institution | Himeji Institute of Technology |
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Principal Investigator |
GOTO Atsushi Himeji Institute of Technology, Faculty of Science, Research associate, 理学部, 助手 (50211917)
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| Co-Investigator(Kenkyū-buntansha) |
MORINAGA Hayao Faculty of Science, Himeji Institute of Technology Associate Professor, 理学部, 助教授 (40210182)
MATSUDA Takaaki Himeji Institute of Technology, Faculty of Science, Professor, 教授(技官) (50145827)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Elevated peneplain / Apatite / Fission track dating / Closure temperature / Thermochronology / Track length / Granitic rocks / Cretaceous volcanic rocks |
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| Research Abstract |
As Matsuda et al., (1997) made clear, the titanite, zircon and apatite fission track ages whose ages provide the cooling ages down to about 300℃, 240℃ and 110℃ respectively were younger than the formation ages of the granitic rocks of the Hida mountains. For the Hida granitic rocks, the apatite fission track ages are rather narrow in range from 40 to 50 Ma, although the zircon fission track ages are wide in range from 99 to 172 Ma. They pointed out that the latest uplift and cooling age that is assumed to be equal to the apatite fission track age with closure temperature of 110℃ was similar through the Hida mountains, 40-50 Ma. Further, they concluded that the age corresponded to the formation age of the elevated peneplain in the Hida mountains. The present work is an extension of their work for detarmination of the formation age of the elevated peneplains of the Japanese Islands. For the present work, we determined the apatite fission track ages of granitic rocks and Cretaceous volcanic rocks. The apatite fission track ages are as follows ; the Kitakami mountains, 82-100 Ma ; the Abukuma mountains, 46-78 Ma (mostly 55-70 Ma) ; Mt. Goto in Niigata prefecture, 6.08 Ma ; the Hida mountains, 40-50 Ma (the pattern of their track length is of slow cooling) ; granitic and acidic volcanic rocks in Chubu district, 45-55 Ma ; Chugoku district, 16-30 Ma ; Awaji and Shikoku islands, 28-46 Ma. The age is narrow in each area. The cooling by about 110℃ differs between areas of the Japanese islands. This suggests that the formation ages of the elevated peneplain deduced from the apatite fission track dating are different from place to place after the Cretaceous time.
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Research Products
(4 results)
