Sedimentological and mineralogical characteristics of Limpopo River Sand at Beit Bridge Border between South Africa and Zimbabwe

Abstract

The research aimed to investigate the sedimentological and mineralogical characteristics of Limpopo River sand upstream of Beit Bridge, situated on the South Africa/Zimbabwe border. Due to limited information available about the minerals and sediments associated with Beit Bridge, this study was conducted to fill this knowledge gap and enhance knowledge of the river’s history and environmental changes. Samples of sediment representing the river were collected from upstream of Beit Bridge along the Limpopo River. The sieve analysis technique was used to classify the particle size of the samples. The X-ray Diffractometer (XRD) analysis identified mineral composition, detecting quartz, feldspar, and other minerals. The petrographic analysis offered detailed mineral component observations, confirming XRD findings. Subsequently the X-ray fluorescence (XRF) analysis traced sediment provenance by identifying specific elements and compounds, illuminating geological history. The results showed that sand was the most dominant component across all stations, with varying proportions of fine silt and gravel. XRD and microscopic analysis revealed minerals such as quartz, plagioclase, microcline, muscovite, and actinolite to be dominant. The prevalence of quartz suggests a quartz-rich source, while plagioclase indicates a predominance of igneous and metamorphic rocks in the local geological formations. The geochemical analysis indicated intense weathering, as evidenced by the high concentration of SiO2 in the sediments. The SiO2/Al2O3 ratio suggests significant leaching processes. Enrichment of Large Ion Lithophile Elements (LILE) in the sediments indicates a provenance from the subduction zone's geochemical region. The Al2O3/TiO2 ratio reflects diverse sources, including basic and ultrabasic plutonic protoliths. These geochemical insights contribute to understanding the area's geological history and mineral resource potential, guiding future exploration and exploitation efforts. The research successfully determined the sedimentological and mineralogical characteristics of the Limpopo River sand upstream of Beit Bridge. The combination of sieve analysis, XRD analysis, petrographic analysis, and XRF analysis yielded valuable insights into the historical transformations in the river's surroundings and the geological mechanisms that influenced the terrain in the examined area.