Structure of the Table Mountain Group in the Port Elizabeth area

Abstract

Selected outcrops along the Baakens valley and coastal strip east of Sardinia Bay were used to determine the overall structure of the Table Mountain Group (TMG) close to Port Elizabeth. A large recumbent fold (nappe?) structure is interpreted to be the result of an early phase of shortening. Pelitic horizons were subsequently smeared out along thrusts in the TMG. This caused repeated stacking, resulting in an unusually thick sequence of quartzites. The last phase of tectonism was extensional. An 8 km broad graben formed between two prominent west-northwest-striking fault zones, the Moregrove and Chelsea-Noordhoek faults