MINERALOGICAL, GEOCHEMICAL, MICROMORPHOLOGICAL AND SPECTRAL ANALYSES OF QUARTZ SANDSTONES IN NORTHWEST CHAD BASIN, NIGERIA

Here, we present quartz sandstone samples observed from widely distributed, white-coloured, uncemented units in and around Matsena village located in northwest of Chad Basin, NE Nigeria. The mineralogical, geochemical compositions and micromorphological characteristics of the quartz sandstones were determined by X-ray diffraction (XRD), X-ray fluorescence (XRF), stereo microscope and scanning electron microscopy (SEM), respectively. The spectral distribution of these lithological units was determined by using Landsat 8 OLI and image enhancement techniques. XRD and XRF analyses reveal that the quartz sandstone samples can be characterized as mature-super mature by their high SiO 2 contents. General appearances of the quartz grains under SEM show rounded to sub-rounded and to a lesser extent sub-angular habits with dish-shaped cavities, V-shaped depressions, mature conchoidal fractures and linear grooves, all of which suggest the mechanical impact on quartz grains from aeolian, fluvial-marine and colluvial environments.