On an Occurrence of Fayalite Quartz-Monzonite in the Basement Complex around Bauchi, Northern Nigeria

Abstract

An unusual fayalite-bearing quartz-monzonite occurs around Bauchi in Northern Nigeria and is distinguished from the high-level fayalite granites of the Newer Granites ring complexes by the presence of a linear structure conformable with those in the surrounding rocks, the gradational nature of its contacts, the extreme coarseness of its mineral constituents and the abundance of myrmekite. It is similar to them in its distinctive green colour and in the high FeO: Fe₂O₃ ratio. The rock is believed to be definitely older than the rocks of the ring-dyke complexes.