South African Committee for Stratigraphy (SACS)
Stratigraphy is not only one of the oldest branches of geology, but is unquestionably also one of the most important, because it considers the form, arrangement, distribution, chronological succession, classification, nomenclature and relationships of all classes of rock. The structure within which these data are compiled is usually provided in publications of formal stratigraphic commissions such as the South African Committee for Stratigraphy (SACS). Prior to 1970, the geological classification and nomenclature of South Africa was uncertain and geologists followed a mixture of methods and approaches from the 1950s to the mid-twentieth century. The science of systematic stratigraphy in South Africa started with the adoption in principle of the recommendations of the International Sub-commission on Stratigraphic Classification in 1970.
The most important function of SACS is to provide and manage a standardised nomenclature and information that provide clear definitions of lithostratigraphic and lithodemic units according to a certain minimum number of characteristics in order to clearly communicate stratigraphic information. The standards for terminology and nomenclature are commonly compiled into stratigraphic codes, which represent the end result of the thought and work of many persons, many hours of writing, and extensive review. The work of SACS is supported by various task group or sub-committees composed of technical experts from academia, internal staff, and industry geologists experienced in geological mapping. These committees are managed by a national committee with policy-making and oversight duties, and collectively represent a resource of a few hundreds of years of relevant experience. The main responsibilities of the task groups are the regulation of stratigraphic nomenclature and control over the publication of lithostratigraphic and lithodemic descriptions in specific areas of geology. Apart from their regulatory responsibilities, task group committees also arrange for the compilation of the definitions of stratigraphic units as SACS descriptions. These descriptions were first published by the former South African Geological Survey/now known as the Council for Geoscience, first as a lithostratigraphic series and later as a more succinct catalogue series. More recently, the publications were replaced by papers in the South African Journal of Geology. SACS also publishes documents under another two series, categorised according to biostratigraphy and chronostratigraphy.
Since the early 1980s to the present, SACS and its collaborators have produced fifty-one (51) full-length lithostratigraphic descriptions and more than 150 catalogue-style, succinct descriptions. SACS has also published more than twenty (20) descriptions in the South African Journal of Geology since 2015 and provided a system based on which more than seventy (70) 1:250 000-scale maps would evolve and be published over more than forty years. This Committee continues to provide the framework within which the latest 1:50 000-scale mapping can continue to develop in an orderly manner.
- Stratigraphy of South Africa. Part 1. Lithostratigraphy of the Republic of South Africa, South West Africa/Namibia, and the Republics of Bophuthatswana, Transkei and Venda (L.E. Kent, compiler). Handbook, Geological Survey of South Africa, 8, 690 pp.
- Johnson, M.R. Guidelines for standardised lithostratigraphic descriptions/Riglyne vir gestandaardiseerde litostratigrafiese beskrywings. Geological Survey of South Africa, Pretoria, 19 pp.
- Johnson, M.R., Cornell, D.H. and Walrafen, F. (editors). A revised Precambrian time scale for South Africa. Chronostratigraphic Series, 1, Geological Survey of South Africa, Pretoria, 6 pp.
- Rubidge, B.S. (editor). Biostratigraphy of the Beaufort Group (Karoo Supergroup). Council for Geoscience, Pretoria, 46 pp.
- South African code of stratigraphic terminology and nomenclature/Suid-Afrikaanse kode vir stratigrafiese terminologie en nomenklatuur. Council for Geoscience, Pretoria, 16 pp.
- Joubert, P. and Johnson, M.R. (editors). Abridged lexicon of South African stratigraphy. Council for Geoscience, Pretoria, 160 pp.