Metamorphic heterogeneities within a single HP unit: Overprint effect or metamorphic mix?

Due to the fact the Western Alps do not reach the mature stage of a colliding belt, as the Central or as the Eastern Alps, the rocks of the Entrelor area can be viewed as an exhumed part of a frozen subduction channel attributed to a metamorphic mixing of rocks having different metamorphic evolution and accreted at great depths.