Abstract
The major portion of the Port Elizabeth municipal area is underlain by rocks of the Table Mountain Group, Cretaceous strata, Recent estuarine and alluvial sediments and semi-consolidated sands. The Alexandra Limestone Formation, raised beach deposits, and dune sands underlie the remainder of the area.
The most significant geotechnical characteristics of the different geological formations are the heaving clays and slope instability problems associated with the Cretaceous strata. Large supplies of construction materials are available. They include sand and gravel which are obtained from the alluvium, crushed stone from the quartzites of the Table Mountain Group, and brick clays from the Cretaceous strata. Salt is produced on a large scale in the Swartkops River valley.
Other noteworthy features in the area include surface and artesian water supplies for Port Elizabeth and the surrounding areas, flooding in the various river valleys, particularly the Swartkops, the coastal and river erosion problems, sewage and solid waste disposal.
