Swartrant Formation

Swartrant Fm

Period:

Permian

Age Interval:

Early Permian (Sakmarian-Kungurian)

Province:
SouthAfrica-Namibia-Botswana

Type Locality and Naming

Ellisras Basin / Waterberg Coalfield (Limpopo Province, South Africa). Named after the farm Swartrant in the Lephalale (formerly Ellisras) district of the Limpopo Province. It was formally defined as a lithostratigraphic unit by C.S. MacRae in the late 1980s to classify the lower, sandstone-dominated coal-bearing succession in the Waterberg Coalfield. Middle formation in Ecca Gr in Ellisras Basin

Synonym:

Lithology and Thickness

A classic fluvio-deltaic succession, typically around 50 to 80 meters thick. Unlike the overlying Grootegeluk Formation (which is highly intercalated coal and shale), the Swartrant Formation is characterized by thick, massive, upward-fining cycles of coarse-grained, cross-bedded, and often gritty arkosic sandstones.

Lithology Pattern:

Coarse-grained sandstone

Relationships and Distribution

Lower contact

Conformably overlies the dark, carbonaceous, deep-water shales and siltstones of the Wellington Fm (the local Lower Ecca / Pietermaritzburg Fm equivalent). Where the Wellington is locally absent, it unconformably rests upon the glaciogenic Waterhoutkop Fm (Dwyka equivalent) or directly on the Precambrian basement rocks.

Upper contact

Conformably and transitionally overlain by the highly intercalated, shale-and-coal-dominated Grootegeluk Fm (Upper Ecca Gr equivalent).

Regional extent

Geographically restricted to the subsurface of the Ellisras Basin (Waterberg Coalfield) in northwestern South Africa. Like most units in this basin, it is primarily known from extensive coal exploration and mining operations. Middle Ecca Gr equivalent. In the mining terminology of the Waterberg Coalfield, it is often informally referred to as the "Lower Coal Zone." It is the direct regional chronostratigraphic equivalent of the Vryheid Fm in the Main Karoo Basin and the Hammanskraal Fm in the Springbok Flats Basin.

GeoJSON

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Fossils

Age

Early Permian (Sakmarian-Kungurian)

Age Span:

Beginning stage:

Sakmarian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

292.02

Ending stage:

Kungurian

Fraction up in the ending stage:

1.0

Ending date (Ma):

274.37

Depositional setting

High-energy fluvio-deltaic environments and expansive peat swamps.

Depositional pattern:

Additional Information

Compiler:

From the O. Catuneanu et al. / Journal of African Earth Sciences 43 (2005) 211–253; MacRae, C.S. (1988): Palynostratigraphic correlation between the Lower Karoo Sequence of the Waterberg and Pafuri coal-bearing basins and the Hammanskraal plant macrofossil locality; Johnson, M.R., et al. (2006): Sedimentary rocks of the Karoo Supergroup. In: The Geology of South Africa; Dreyer, J.C. (1999): The stratigraphy and sedimentation of the Vryheid Formation equivalent in the Waterberg Coalfield.