Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and mineralogy - Vol.XX, Nos.2-3

Rb-Sr Age of the Yurappu-dake Plutonic Complex in Southwestern Hokkaido

Nishikawa, Jun'ichi;Hashimoto, Masahiko

Permalink :  http://hdl.handle.net/2115/36713

Abstract

A Rb-Sr whole-rock age and two whole rock-mineral ages of the Yurappu-dake Plutonic Complex in southwestern Hokkaido were determined. The Rb-Sr whole-rock age is 115 ± 9 Ma with an initial 87Sr/86Sr ratio of 0.7057 ± 0.0001, whereas the whole rock-mineral ages are 70 ± 7 and 74 ± 3 Ma. It is suggested that the Yurappu-dake Plutonic Complex had a Sr isotopic heterogeneity when the whole-rock system was closed.


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