University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan Division of Earth Sciences, Department of Environmental...Kyushu University, Motooka 744, Fukuoka 819-0395, Japan a r t i c l e i n f o Article history: Received...and Al2SiO5 components plotting within the Jd (Na,K)(Al,Cr)(Si,Ti) 2O 6 −Qtz (Si,Ti)O 2 −Grt M3 (Al,Cr)...ultrahigh-pressure phases such as coesite, microdiamond, talc, K-rich clinopyroxene and/or Na-rich garnet (Klemd, 2003;...the Tertiary Hidaka metamorphic belt in Hokkaido, Japan (Osanai et al., 1992); (2) pulverised high-magnesian |