High-pressure metamorphism of the Joetsu Belt viewed from boulders in the Miocene Awazawa Formation, Minakami Town, Gunma Prefecture, Japan

Abstract

Paleozoic high-pressure metamorphic rocks of the Joetsu belt appear only as sporadic small outcrops on top of the Mt. Tanigawa-dake and as boulders in the Miocene Awazawa Formation. Shimizu et al. (2000, Geol. Soc. Japan 107th Meeting Abst. 289; 2001, GSJ 108th Meeting Abst. 160) reported petrologic nature of those basic and pelitic schists. Combining these petrographic and mineral chemical data, we discuss nature of the Joetsu high-pressure metamorphis, and compare it with those of the Renge, Sambagawa and Kamuikotan high-pressure metamorphic belts.