Micromorphological and microchemical characterisation of mosheneng Serpentinite associated with the Neo-Archaen Taupone Dolomite Group, Botswana

This work aimed at elucidating on the micromorphology and microchemistry of serpentine minerals occurring in the Moshaneng Serpentinite associated with the Neo-Archaen Taupone Dolomite Group, Botswana. Samples obtained from Moshaneng Serpentinite abandoned mine were analysed by environmental scanning electron microscopy (ESEM) and energy dispersive X-ray (EDX) spectrometry in order to identify and characterise their mineral constituents. The micromorphology of the samples depicted fine grained platy lizardite and tubular fibre veins of chrysotile. Results of microchemical analyses indicated that the samples consisted of MgO and SiO sub(2) in acceptable wt %ages for serpentine. Varied wt %ages of A1 sub(2)O sub(3), Fe sub(2)O sub(3), CaO, SO sub(2), C1 sub(2)O, K sub(2)O, TiO sub(2), and MnO in the samples could be due to isomorphic substitution of Al and Fe in the octahedral and tetrahedral sheets of serpentine. Mineralization in Moshaneng Serpentinite is considered to have been of two phases: the first being the formation of lizardite through isochemical serpentinization of olivine; and the second being the mineralization of chrysotile by allochemical serpentization of lizardite. Because chrysotile is the dominant asbestos mineral in the Moshaneng Serpentinite, aspects of environmental and human health as well as rehabilitation of the abandoned mine should be addressed with exigency.