Granulometric and morphoscopic analyses of mineral sediments in the Poni watershed in Burkina Faso

Abstract

The Poni River basin in southwestern Burkina Faso is a complex geomorphological
system based on a crystalline geological structure where water, sediments, and human
activities interact. The study of grain size distribution using the sieving method on
sediments resulting from water dynamics involved, first, determining the distribution  of different particle sizes in each sediment sample and, secondly, calculating the
Skewness and Trask indices. Morphoscopy, performed using a binocular microscope,
facilitated the characterization of the shape and surface of the quartz particles. The
results, shown as grain size distribution curves in the first case, indicate the
proportions of particle sizes, with their homogeneity indicated by the skewness index.
In the second case, observations of the quartz grains primarily allowed for the
deduction of the sediments’ fluvial origin, their transport distance, and, most
importantly, the processes to which they were subjected. These analyses help to assess
the impact of erosion on water resources and agricultural land, and to better manage the risks
associated with these processes.