Rb- Sr isochron dating of granitoids from the Kazaure schist belt, Nigeria

Abstract

The results of Rb-Sr isochron dating of granites from the crystalline basement complex of Kazaure Schist Belt are presented in this paper. Whole rock Rb-Sr radiometric age determination of five samples of a syntectonic coarse-grained porphyritic granite define a 4-point whole-rock Rb-Sr isochron (MSWD=1.2) corresponding to an age of 592 + 14 Ma, the initial 87Sr/86Sr ratio being 0.7097 + 0.0004. This is distinctly a Pan-African age and is taken as the time of emplacement and crystallization of a granitic magma formed from a reworking of a pre-existing continental crust. The initial 87Sr/86Sr ratio indicates a significant contribution of older crustal materials by partial melting to the granitic magma.

Key Words: Kazaure Belt, Geochronology, Isochron, Pan-African, Crust.


(Global Journal of Pure and Applied Sciences: 2002 8(3): 319-324)