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

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.