ENVIRONMENTAL GEOLOGICAL ASPECTS OF THE DOLOMITES OF SOUTH-AFRICA

The dolomite rocks in South Africa coincide for the most part with the so-called Pretoria-Witwatersrand-Vereeniging complex which comprises the industrial heart of the country. Urban development will, therefore, also be concentrated in this area, with the inevitable establishment of townships on the dolomite. This development has great impact on the dolomitic environment and vice versa. The most important environmental aspects which influence Man's occupation of the dolomite environment include the formation of sinkholes and dolines (compaction subsidences) and also the potential pollution of the dolomite aquifers. These aquifers consist of weathered, blanketing materials overlying the bedrock with sometimes shallow water levels, high permeabilities, storativities and transmisivities. All these factors contribute to the excellent groundwater resource in the dolomite rocks as well as to their high pollution potential. The environmental hazards associated with development of dolomite land is discussed with reference to loss of life, financial implications and efforts to reduce the impact of development. The importance of pre-emptive and appropriate land management is stressed. A clear understanding of the dolomite environment is, therefore, essential.