Mineralogical and Physical Characterisation of QwaQwa Sandstones
Mineralogy, texture and sedimentary structure are essential to the study of all sedimentary rock. Sandstones from QwaQwa rural area in South Africa were characterised for their mineralogical and physical properties. Six samples (whitish, greenish, blackish, reddish, yellowish and greyish) were collected and studied. The X-ray Diffraction (XRD) revealed that the samples were quartz based. Scanning Electron Microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS) revealed the differences in the morphology and Silicon element was found present in all the samples. The X-Ray Fluorescence (XRF) exhibited that the samples contained 43.14 % of Silicon (whitish). The grain sizes of the samples ranged from coarse, medium to fine grains. The Greyish sample had the highest compressive strength value of 56.74 MPa. Dielectric properties measurements were also conducted on the samples; and the results were temperature dependant. The water absorption by total immersion revealed that the blackish sandstone had the highest percentage of 6.62 %. Furthermore, the greyish sandstone had the highest density (2.7235 g/cm3) and the reddish sample had the lowest (2.6502 g/cm3).
KeywordsCompressive strength Density Dielectric properties Phase identification Quartz Sandstones Water absorption
The author acknowledges Prof A. F. Mulaba-Bafubiandi for initiating the project on QwaQwa sandstones. Fikile Moreti sandstones (Mr. Karafu, QwaQwa, South Africa) for providing the sandstone samples. The financial support of the University of Johannesburg is acknowledged.
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