Major oxides distribution, provenance, and tectonic settings of the mudstones from Gombe Formation, Gongola Basin, Upper Benue Trough, Nigeria

Abstract

The Gombe Formation in northeastern Nigeria contains mudstones, along with other sedimentary rocks like sandstones, shales, and coals. To date, however, the major oxides geochemical studies of these mudstones are still poorly documented. The present study investigated the geochemical importance of major oxides in the mudstones from Gombe formation, Upper Benue Trough, Nigeria by x-ray fluorescence spectrometry (XRF) within the context of provenance, tectonic environments, and paleosalinity. Among the twenty (20) major oxides identified, the mudstones exhibit elevated levels of SiO₂, with Al₂O₃ >Fe₂O₃>MgO>TiO₂>K₂O>BAO>SrO; whereas the remaining oxides demonstrated low concentrations. This suggests that mudstones were predominantly constituted of quartz minerals and were formed in marine settings. The relatively elevated levels of Fe₂O₃ (with an average of 3.36 %) and MgO (with an average of 2.48 %) in the samples indicated that the source rocks were likely to be mafic to ultramafic. The major oxides ratios in the mudstones indicated that the sediments were derived from a mixture of felsic igneous and mafic igneous rocks with mixed compositional maturity in close proximity to the active continental margin. This study showed that major oxides were effective in evaluating the provenance and tectonic settings of the mudstones from Gombe formation in Gongola Basin, Nigeria.