metasomatism
noun
meta·so·ma·tism ˌme-tə-ˈsō-mə-ˌti-zəm 
: metamorphism that involves changes in the chemical composition as well as in the texture of rock
metasomatic
ˌme-tə-sō-ˈma-tik
adjective 
Word History
Etymology
metasomatic from German metasomatisch, from Greek meta- + sōmat-, sōma body
First Known Use
1886, in the meaning defined above