The contact relationship of charnockite and biotite gneiss at Bauchi, northern Nigeria
Moshobalaje Olaloye Oyawoye
"Petrographic and chemical study of biotite gneiss and charnockite and the gradational transition zone between them suggests three probable modes of origin: (i) that charnockite was regionally widespread and the biotite gneiss was derived from it by retrograde metamorphism; (ii) that the charnockite represents a conformable intrusive igneous rock which with biotite gneiss was subjected to high-grade metamorphism; (iii) that the charnockite was derived from the biotite gneiss, by the introduction of some ferrous-iron rich juvenile solution. The latter is preferred."
This record provided courtesy of AGI/GeoRef.
