possibly

but the most common process results from superheaing (Vernon, 1985, Geology, 13, 846-845). it could b caused by the falling of a felsic hydrous magma into a magma chamber. this would led to orbicukes with core as a K-feldspar. in case of a cordierite core, it could result of a part of the roof falling into the magma chamber (abdallah et al., 2007, Jour frixan Earth Sci, 49, 153-178)

i could mail you those papers

jl

JL: Don't remember what Ron Vernon wrote but, why can't it be simple partial wall rock assimilation (e.g., roof falling) or magma mingling WITHOUT requiring superheat? It is very unusual for magma to carry superheat. Just a thought.