Preliminary assessment of the physico-mechanical properties and rock quality of the sedimentary rocks in the Northern Volta Basin, Ghana

This study presents a preliminary evaluation of the aggregate potential of representative sedimentary rocks from the Voltaian Supergroup in northern Ghana. Fifteen rock samples were collected from Gambaga, Pigu and Tamale, representing the Bombouaka, Oti-Pendjari and Obosum Groups. They were analysed using petrography, SEM–EDX and standard physico-mechanical tests conducted in accordance with BS 812 and ASTM procedures. Petrographic and microanalytical results indicate that the Bombouaka and Obosum samples are quartz-rich sandstones, whereas the Oti-Pendjari sample is a fine-grained calcareous rock with a micritic carbonate matrix and subordinate siliciclastic constituents. The physico-mechanical results reveal clear lithological contrasts in engineering performance. The Oti-Pendjari rock records the lowest aggregate impact, crushing and Los Angeles abrasion values (16%, 18% and 25%, respectively), indicating superior resistance to impact, crushing and wear. The Obosum sandstone shows moderate performance, whereas the Bombouaka sandstone performs poorly despite its high quartz content. These results demonstrate that aggregate quality in the Voltaian Supergroup is governed not only by mineralogical maturity, but also by textural and diagenetic controls, including grain support, matrix content and cementation. The study provides the first integrated preliminary dataset linking petrographic characteristics with engineering behaviour for selected Voltaian sedimentary rocks, and highlights the need to evaluate sedimentary aggregate resources based on fabric and rock quality rather than quartz abundance alone.