Ferruginised metapelites of the Kazaure Schist belt, northwestern Nigeria

Abstract

Field, petrographic and geochemical evidence shows the occurrence of ferruginised metapelites (FMP) in the Kazaure Schist Belt (KZSB). The KZSB consists predominantly of quartzites, pelitic metasediments, and metaconglomerates. Minor rocks includes metavolcanics and iron formations (Banded Iron Formation and ferruginised metapelites). The FMP occurs as narrow bands associated with quartzites and phyllites. Magnetite as euhedral to subhedral crystals together with subordinate anhedral hematite forms the Fe band. The Fe content of the FMP (14.54-82.8 %) is comparable to that of banded iron formations in the schist belt. It contains lesser amounts of Mn (0.07-17.83 %), Ca (0.067-1.25%), and the lithophile elements average values: K (1.21 ppm); Rb (89.89 ppm); Sr (190.78 ppm). It is envisaged that the FMP developed from the alteration of the metasediments entrapped as a kind of tectonic mélange as a result of late tectonic brittle deformation and activity of fluids rich in iron.