in the asemi-gawa area of intermediate high-pressure and low-temperature sanbagawa metamorphic belt in central shikoku, japan, piemontite-quartz schists are common in which cation exchange between piemontite and garnet has been studied. piemontite in contact with garnet usually contains two zones in which core is enriched in mn3+ and surrounded by a rim rich in fe3+. garnet is ca-fe-bearing spe...

In the Asemi-gawa area of intermediate high-pressure and low-temperature Sanbagawa metamorphic belt in central Shikoku, Japan, piemontite-quartz schists are common in which cation exchange between piemontite and garnet has been studied. Piemontite in contact with garnet usually contains two zones in which core is enriched in Mn3+ and surrounded by a rim rich in Fe3+. Garnet is Ca-Fe-bearing spe...

Determining the Mn valence variation at nanometer scale will be an important advance in study of heterogeneous natural silicates. Here, potential scanning transmission X-ray microscopy L2,3-edges (640–655 eV) as a probe for manganese redox state is evaluated. For this purpose, several Mn-silicates (rhodonite, ardennite, piemontite, Mn4+-silicate, jacobsite) were analysed to identify spectral pa...