GEOCHEMICAL EVOLUTION AND FIELD RELATION OF MIGMATITES AROUND DIR, BAUCHI, NORTHEASTERN NIGERIA

Abstract

The migmatite rocks around Dir, in Bauchi Local Government Area of Bauchi State were 
studied with the interest to determine the geology, field relation, geochemical evolution and 
morphology of the study area. The geological mapping indicated various morphological 
units of migmatites; Diatexite migmatites occurring as Melanocratic-diatexite, 
Mesocratic-diatexite and Leucocratic-diatexite. Field studies showed the presence of the 
various rock forming minerals which comprises of plagioclase, quartz, biotite, microcline 
and muscovite. Geochemically, a slight inverse correlation between SiO2 and few oxides 
is observed. This suggests that the classic model of fractional crystallization is not the 
principal process influencing the lithological diversity but partial melting in which the   
correlation patterns are controlled by the geochemistry of the solid phases been added 
to the melt. Correlation of the geochemical data and their field occurrence reflects that the 
leucocratic-diatexite has highest amount of added fluid. The geochemical variations 
observed for the migmatites showed they were formed within the volcanic arc granite 
and oceanic ridge granite tectonic setting. A model was used to determine the parents of 
the migmatites in the study area. In the plot the migmatites fell within sedimentary and 
igneous field which suggests that the protoliths of the migmatites are of sedimentary and 
igneous rocks.