Petrographic Analysis of Rock Samples in Bui Division North West Region of Cameroon: Implications on Water Mineralization and Classification.

Abstract

Percolation of water through rock samples is the main agent of the chemical weathering of most rocks. The rock- water interactions are identified as the main process responsible for water mineralization. The ionic content of any water source is dominantly expected to be as a consequence of these interactions. These assertions were verified in this work. In a bid to determine the possible ions in any water source and obtain its water type, a petrographic analysis of the rock samples within the water source vicinity and the geological set up of the entire zone is imperative. To put into evidence this inference, five water catchments, 29 boreholes. 16 Open wells, 16 rivers and 16 streams were studied in this work. Scrupulously sampling in accordance to the norms of the art was done and water samples taken immediately to the Laboratory for physico-chemical analysis. A petrographic analysis of the rock samples from Bui division was done using Dave’s method in which thin section slides were prepared from the rocks for a microscopic identification of the minerals present. The rocks were basalts, trachytes, rhyolites, ignimbrites, phonolites and scoria characteristic of the dominant volcanic area, with granites in some plains. Water samples were analysed to deduce the relationship between the ions present and their origin from the dissolution of the rock minerals. Nonetheless, there is a likelihood of ions to be present in water sources from anthropogenic sources, but the aim of this article is to discern if the ions in water are dominantly from rock mineral dissolution or from other sources. The ions in the water samples were used to determine the main water type in Bui division. From the rock thin sections, the Modal composition of each rock type was also established. At the end of this research, it was emphatically revealed that rock-water interactions and the resultant mineral dissolution was the main mechanism responsible for mineralization of water sources in Bui division.