autometamorphism
/ˌɔːtə(ʊ)ˌmɛtəˈmɔːfɪz(ə)m/noun
Geology. Metamorphism of an igneous rock caused by the action of volatile constituents of the rock itself, under conditions of falling temperature.
Origin
Mid 19th century (in an earlier sense). From auto- + metamorphism.