A Pb, Sr and Nd isotope study of the basement and mesozoic ring complexes of the Jos Plateau, Nigeria

Combined Pb, Sr and Nd isotope determinations on several Nigerian Mesozoic ( 170 Ma) ring complexes, studied previously by van Breemen and co-workers, indicate a multistage petrogenetic process. Mantle-derived differentiated magmas assimilated crustal basement of average Early Proterozoic age. After crystallisation, some plutons were subjected to a second stage of crustal contamination by circulating hydrothermal fluids.Crustal compositions …