Geometrical relations between the Transvaal Supergroup, the Rooiberg Group, and the mafic rocks of the Bushveld Complex: a discussion (S.Afr. J. Geol., 101, 275-279)

Abstract

In his paper on the geometrical relations between the Transvaal Supergroup and the Bushveld Complex, Cawthorn ( 1998) argues that there is ·no need to infer a considerable period of pre-Rooiberg Group erosion prior to emplacement of the Bushveld Complex-Rooiberg volcanic rocks. He further suggests that a significant time interval between the Pretoria and Rooiberg Groups is now common knowledge, but that the extent of Pretoria Group erosion before Rooiberg volcanism is unknown. We note that these two proposals of Cawthorn (1998) are not readily compatible: a considerable time gap should in fact promote a reasonable amount of weathering and erosion between the deposition of the two groups. We wish to contribute positively to the debate on the relationship· of the Transvaal and Bushveld rocks by qualifying the proppsals of Cawthorn (1998) on the basis of the evidence presented below.