Volkrust Formation

Volkrust Fm

Period:

Permian

Age Interval:

Middle Permian (Wordian)

Province:
SouthAfrica-Namibia-Botswana

Type Locality and Naming

Main Karoo Basin (Eastern/Northern Forebulge). Named after the town of Volksrust in the Mpumalanga Province of South Africa, near the border with KwaZulu-Natal. It was formally designated as the uppermost argillaceous (muddy) unit of the Ecca Group in the northeastern part of the Karoo Basin. Lowermost formation in Beaufort Gr in Main Karoo Basin (Eastern/Northern Forebulge)

Synonym:

Lithology and Thickness

A thick, predominantly argillaceous, and highly monotonous basinal succession. It consists almost entirely of dark grey to black, finely laminated to massive, silty shales and mudstones.

Lithology Pattern:

Claystone

Relationships and Distribution

Lower contact

Conformably and abruptly overlies the coarse, sandy, and coal-bearing deltaic deposits of the Vryheid Fm.

Upper contact

Conformably and transitionally overlain by the sandy, fluvio-deltaic deposits of the Normandien Fm (or the Estcourt Fm further south), which represent the basal units of the Beaufort Group (Adelaide Subgroup).

Regional extent

Widespread across the northern, northeastern, and central sectors of the Main Karoo Basin, outcropping extensively in Mpumalanga, KwaZulu-Natal, and the Free State provinces. Upper Ecca Gr. It roughly correlates chronostratigraphically and environmentally with the Fort Brown and Waterford Fm in the southern and western parts of the Main Karoo Basin, and broadly with the Lower Madumabisa Mudstone Fm in Zimbabwe.

GeoJSON

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Fossils

Age

Middle Permian (Wordian)

Age Span:

Beginning stage:

Wordian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

269.21

Ending stage:

Wordian

Fraction up in the ending stage:

1.0

Ending date (Ma):

264.34

Depositional setting

Deep-water, low-energy offshore to extensive inland sea or deep lacustrine environment.

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; Tavener-Smith, R., et al. (1988): Sedimentary models for coal formation in the Vryheid Formation, northern Karoo Basin; Rubidge, B.S., et al. (2000): Timing of the "Great Dying" in South Africa...