A 3D geological model for the East Rand Basin, South Africa

Abstract

The primary aim of this dissertation is to map the geology of the East Rand Basin accurately by creating a 3D model. This was done by using borehole data from the National Groundwater Archive Geodatabase, which the Department of Water and Sanitation collected, and the average depths derived from the literature. Triangulated irregular networks (TINs) and digital elevation models (DEMs) surfaces were created from these data points to determine the depths for areas with no borehole data. Using these surfaces, three methods were used to create three main models. These models were then compared to one another, other geological maps and cross-sections to determine the most accurate and practical model of the three. It was found that the quality and quantity of the data from the National Groundwater Archive Geodatabase were not sufficient for these models; therefore, the results and accuracy of each layer was questionable. This dissertation found that these methods can be used for basic geological studies if the data are of the same quality and quantity. However, if the data are more evenly distributed and higher in quantity, these methods can be used to create more accurate models. Furthermore, the use of commercial software was recommended in this study. The reason for recommending these tools is that they have been specifically designed to create geological layers from boreholes within the ArcGIS software. These tools also allow the user to create cross-sections within ArcGIS.