Vryheid Formation

Vryheid Fm

Period:

Permian

Age Interval:

Early-Middle Permian (Artinskian-Roadian)

Province:
SouthAfrica-Namibia-Botswana

Type Locality and Naming

Main Karoo Basin (Eastern/Northern Forebulge). Named after the town of Vryheid in northern KwaZulu-Natal, South Africa. It was formally established to encompass the main coal-bearing sequence of the Ecca Group in the northern and northeastern portions of the Karoo Basin. Upper formation in Ecca Gr in Main Karoo Basin (Eastern/Northern Forebulge).

Synonym:

Lithology and Thickness

A thick, economically vital siliciclastic succession, typically ranging from 300 to 500 meters in thickness.

Lithology Pattern:

Claystone

Relationships and Distribution

Lower contact

Conformably and transitionally overlies the dark, deep-water shales of the Pietermaritzburg Fm.

Upper contact

Conformably, but rapidly, overlain by the dark basinal shales of the Volksrust Fm.

Regional extent

Extensively distributed across the northern, northeastern, and central sectors of the Main Karoo Basin, outcropping heavily in the Mpumalanga, KwaZulu-Natal, and Free State provinces. It hosts the vast majority of South Africa's economic coal reserves. Middle Ecca Gr (historically). It correlates chronostratigraphically and environmentally with other major coal-bearing units across Gondwana, including the Black Shale and Coal Gr (Wankie Coal Fm) in Zimbabwe and the Mmamabula Fm/Morupule Fm in Botswana.

GeoJSON

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Fossils

Age

Early-Middle Permian (Artinskian-Roadian)

Age Span:

Beginning stage:

Artinskian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

290.51

Ending stage:

Roadian

Fraction up in the ending stage:

1.0

Ending date (Ma):

269.21

Depositional setting

Extensive fluvio-deltaic, coastal plain, and paludal (peat swamp) environments.

Depositional pattern:

Additional Information

Compiler:

From the O. Catuneanu et al. / Journal of African Earth Sciences 43 (2005) 211–253; Johnson, M.R., et al. (2006): Sedimentary rocks of the Karoo Supergroup. In: The Geology of South Africa; Cadle, A.B., et al. (1993): The Vryheid Formation of the Main Karoo Basin, South Africa...; Tavener-Smith, R., et al. (1988): Sedimentary models for coal formation in the Vryheid Formation, northern Karoo Basin.