A Geophysical Case Study Of A Copper-Zinc Sulphide Deposit In The Northern Cape

The 1989 Wits University Geophysics Field School was held at<br>Copperton, 60km southwest of Prieska, northern Cape. With the<br>permission of Anglovaal Ltd., an intensive geophysical study was<br>carried out over the annex to the main sulphide ore body. The<br>geology of the deposit is described in detail by Wagener and Van<br>Schaikwyk (1986). At the site of the Annex sulphide body, the host<br>rocks are overlain by a thin layer of tillite of the Dwyka Formation.<br>Calcrete is locally developed. On the basis of previous work<br>(Anglovaal Ltd.), two lines on the existing survey grid ware chosen<br>for detailed study. Various techniques were used, and instrument<br>responses were compared over these two lines, each 500m long and 200m<br>apart. We present data from one of these lines (Fig. 1). The<br>techniques used ware EM (Geonics EM-34, Crone Pulse EM, Scintrex<br>Genie), time domain IP (gradient array), SP, resistivity sounding<br>(Schlumberger array) and profiling (gradient array), gravity,<br>magnetics and hammer refraction seismics. The results and a<br>qualitative interpretation follow.