Landscape settings and mineralogy of some geophagic clay occurrences in south africa

Abstract

In the regions of Asia and Africa geophagic clays are traditionally used by population based on historical and traditional motivations including ethno-medical ones. The aim of the present research was to reveal the general common properties of some geophagic clay occurrences based on their mineral composition and landscapes specificity, in which they were sampled. In addition to assess the potential source of the minerals in geoghagic clays, the mineral association of the hard rocks, located in geophagic loose material, was studied too. Mineralogy of the samples was investigated using X-ray diffractometry, FTIR spectroscopy, and optical microscopy. The studied samples were collected in two provinces of South Africa: Free State and Limpopo. It was shown that location of geophagic materials is spread widely in the studied provinces. Using material as geophagic is more historically and traditionally determined than by the type or specificity of a landscape, which cannot be characterized by common features. Whereas it was revealed that despite the differences in location and rock geneses, the most common mineral in the fine size fraction of the studied geophagic samples is smectite—a fine-sized clay mineral with high specific surface area being able to play a role as adsorbent.