- © 2007 Geological Society of South Africa
Nannofossil assemblages extracted from rock samples collected at depths of between 33 and 15 metres on the Aliwal Shoal, a submerged aeolianite and beachrock complex on the southeast African continental shelf, indicate a late Middle Pleistocene to Holocene (calcareous nannofossil zone NN21) age for both the aeolianite core and younger abutting beachrocks. This indicates that the older aeolianite core, forming the dune ridge, is no older than ~290 000 years BP. The presence of reworked Cretaceous (Campanian to Maastrichtian), Palaeogene and Pliocene forms in younger beachrocks suggests periodic exposure of those sequences on the outer shelf. The most recent sea level lowstand at approximately −125 m during the Last Glacial Maximum (~18 000 years BP) is considered the most likely event releasing these older forms and their subsequent incorporation into the beachrocks during the ensuing post-Last Glacial transgression.