Fig. 1
From: Thermodynamic forward modeling of retrogressive hydration reactions induced by geofluid infiltration
a Microphotograph in plane polarized light and b X-ray map of Al concentrations showing the characteristics of retrogressed mafic schist in the Sanbagawa metamorphic belt. In amphibole grains (Amp), the Al-rich core (Amp, core) is barroisite, whereas the Al-poor mantle (Amp, Mtl) is actinolite. Microstructural observations indicate that actinolite and lower-grade metamorphic minerals such as epidote (Epi) and chlorite (Chl) grew at the expense of core barroisite, which is a non-equilibrated phase (Okamoto and Toriumi 2005) (for more details, see Additional file 1). Note: this X-ray map was kindly provided by Dr. A. Okamoto