| Project/Area Number |
03452068
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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 |
地質学一般
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| Research Institution | Nagoya University |
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Principal Investigator |
ADACHI Mamoru Nagoya University School of Science Associate Professor, 理学部, 助教授 (10113094)
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| Co-Investigator(Kenkyū-buntansha) |
KOJIMA Satoru Nagoya University School of Science Assistant Professor, 理学部, 助手 (20170243)
TANAKA Tsuyoshi Nagoya University School of Science Professor, 理学部, 教授 (00236605)
SUZUKI Kazuhiro Nagoya University School of Science Associate Professor, 理学部, 助教授 (90111624)
MIZUTANI Shinjiro Nagoya University School of Science Professor, 理学部, 教授 (50022538)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1992: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1991: ¥4,600,000 (Direct Cost: ¥4,600,000)
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| Keywords | CHIME (Chemical Th-U-total Pb Isochron Method) / Detrital heavy minerals / Precambrian zircon / Precambrian detrital monazite / Hida terrane / Mino terrane / Maizuru terrane / Kurosegawa terrane / 砕屑性ジルコン / トリウムーウランー全鉛アイソクロン年代 / キ-ワ-ド / 壺ノ沢片麻岩 |
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| Research Abstract |
(1) Precise electron microprobe analysis of monazite and zircon grains has been successful to develop a new dating method: CHIME (Chemical Th-U-total Pb Isochron Method).
(2) CHIME ages of detrital monazite grains in Jurassic sandstones of the Mino and Hida terranes concentrate around 1750-1400 Ma, with minor concentrations around 1250, 850 and 250 Ma.
(3) CHIME ages of detrital monazites from the Upper Triassic Nabae Group in the Maizuru terrane range largely from ca. 400 to 500 Ma, being much younger than those from the Mino and Hida terranes.
(4) Monazite and zircon grains from the Gray Granite, intruding the Hida gneiss in central Japan, yield CHIME ages of ca. 250 Ma; this age is much different from the previously-reported Precambrian Rb-Sr whole-rock age for the Gray Granite.
(5) The Tsubonosawa paragneiss included in the Hikami Granite in the South Kitakami terrane yield CHIME zircon ages of 350-2000Ma; rarely some well-rounded zircon grains show an Archean age as old as 3000Ma.This is the first record of Archean detrital zircons from the Japanese Islands.
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