Gravity Anomalies and Crustal Structure in South Africa

Abstract

Summary In this paper an account is given of the isostatic anomaly field in South Africa. Estimates of crustal thickness are made by using the regression coefficient criterion proposed by Heiskanen, the minimum sum of squares criterion proposed by Bowie and a new criterion based on minimum sum of squares of departure from the regression lines. It is found that the regression coefficient criterion is not satisfactory because it is sensitive to systematic effects such as arise in South Africa near the escarpment. The other criteria yield results which are consistent with the seismically inferred crustal structure, i.e. with a crustal thickness 30–40 km.