African Natural History
On-line version ISSN 1816-8396
MCMILLAN, Ian K.. Reappraisal of foraminiferal assemblages of the Santonian-Campanian Mzamba Formation type section, and their correlation with the stratigraphic succession of the KwaZulu Basin. Afr. nat. history (Online) [online]. 2008, vol.4, pp. 25-34. ISSN 1816-8396.
Recent processing of additional samples, re-processing of the M. Makrides samples and re-evaluation of benthic and planktic foraminifera assemblages previously described from Mzamba Cliff, has led to the finding of several rare species that support previous ammonite datings of the succession. These include numbers of the planktic species Dicarinella asymetrica (Sigal) and Sigalia sp., which are limited to the Middle to Late Santonian, and to the Middle Santonian, respectively. Sigalia sp. appears to be a different species from the widely distributed Sigalia deflaensis (Sigal), as it is distinguished by depressed sutures throughout. Alternatively Sigalia sp. maybe avariant limited to shallow or temperate waters; or it may be a juvenile form of Sigalia deflaensis. In addition, rare tests of the Santonian larger benthic foraminifera Pseudosiderolites sp. have been found, the first such larger foraminifera from the Late Cretaceous succession of southern Africa. Comments on the possible stratigraphic value of a species of Cyclammina occurring through the Campanian interval at Mzamba Cliff are also included. A palaeoecological review is presented, as well as an updated attempt at a foraminiferal bed-by-bed stratigraphy of the Mzamba outcrop succession.
Keywords : Cretaceous; Santonian; Campanian; benthic; planktic; foraminifera; mudbelt.