R8: Metamorphic rocks and tectonics

[R8-14] Re-proposal of a Metamorphic zoning in the Horokanai Area of Kamuikotan Metamorphic Belt

*Takao Hirajima¹, Wataru Yabuta¹, Kohta Minagawa¹, Kohichi Kataoka¹, Shusuke Kinoshita¹, kazuyuki Dohmen¹ (1. Kyoto Univ.)

Keywords:blueschist, lawsonite, petrogenetic grid, Kamuikotan belt

In the Horokanai area of the Kamuikotan Metamorphic Belt, Hokkaido, Japan, a metamorphic zoning based on the presence or absence of lawsonite and epidote in the blue schist and a zone classification based on the K-Ar age of white mica have been proposed, but each proposal has its own problems (see Takeshita et al., 2018). In this study, we find a systematic distribution of the low-variant mineral assemblages in meta-basaltic rocks in the relevant area and verify their significance using the model petrogenetic grid.