Fission-track zircon ages of psammitic schist from the chlorite zone of the Sambagawa metamorphic belt, central Shikoku, Japan: two distinct ages, and implications
地質学雑誌 = Journal of the Geological Society of Japan
巻
117
号
1
ページ
53 - 56
発行年
2011-01-01
ISSN
0016-7630
NCID
AN00141768
DOI
10.5575/geosoc.117.53
出版者
日本地質学会 = Geological Society of Japan
抄録
We analyzed the fission-track (FT) thermochronology of zircon in two samples of psammitic schist from the chlorite zone of the Sambagawa metamorphic belt, central Shikoku, Japan. The samples were collected from the lower-grade part of the chlorite zone (pumpellyite-actinolite facies). Detrital zircons from a single locality along the Asemi River are completely annealed, yielding FT ages of 92.6±6.2 Ma (1σ, 13 grains), and those from a single locality along the Dozan River are also completely annealed, yielding FT ages of 47.2±3.8 Ma (1σ, 7 grains). Although both samples were collected from within the chlorite zone, the two FT zircon ages are different, possibly because they represent the timing of peak metamorphism in the former sample, and a D3 thermal event (post peak-metamorphism) in the latter sample.
四国中央部三波川帯緑泥石帯砂質片岩中のジルコンのフィッショントラック年代: 2つの異なる年代とその意味
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