The Chandman massif, a typical structure of the Mongolian Altai, consists of a migmatite-magmatite core rimmed by a lower grade metamorphic envelope of andalusite and cordierite-bearing schists. Theoldest structure in the migmatite-magmatite core is a subhorizontal migmatitic foliation S1 parallel to rare granitoid sills.
This fabric is folded by upright folds F2 and transposed into a vertical migmatitic foliation S2 that is syn-tectonic, with up to several tens of metres thick granitoid sills.