Integration and Data-driven Zonation of Large Airborne Geophysical Maps Using Cluster Analysis

Since the advent of modern desktop computers few attempts have been made towards rapid, automated and objective information extraction from large geophysical data suites. We employ fuzzy c-means (FCM) cluster analysis for the rapid and objective integration of disparate geophysical data sets comprising airborne radiometric and magnetic as well as ground-based gravity data covering a survey area of approximately 5000 km2 located 100 km east-south-east of Johannesburg, South Africa. After preparatory data processing and normalization, the three data sets are subjected to FCM cluster analysis resulting in the generation of a zoned integrated geophysical map delineating distinguished subsurface units based on the information the three input data sets carry. We refer the zoned geophysical map to all available geological information demonstrating that the zoned geophysical map as obtained from FCM cluster analysis outlines geological units which are related to Bushveld-type, other Proterozoic- and Karoo-aged rocks.