Progressive regional dynamothermal metamorphism of the kyanite-sillimanite type has been
recognized in the Uwet area of the Oban massif in southeastern Nigeria. Metamorphic
isograds, based on the entry of pelitic index minerals, biotite, garnet, kyanite and sillimanite
have been mapped. The distribution of these isograds indicates a northwest to southeast
increase in the intensity of metamorphism in the Uwet area from medium greenschist facies
to uppermost amphibolite facies. The presence of kyanite and sillimanite indicate high …