Wellington Formation

Wellington Fm

Period:

Permian

Age Interval:

Early Permian (Asselian-Sakmarian)

Province:
SouthAfrica-Namibia-Botswana

Type Locality and Naming

Ellisras Basin / Waterberg Coalfield (Limpopo Province, South Africa). Named after the farm Wellington in the Lephalale (formerly Ellisras) district of the Limpopo Province. It was formally established as a lithostratigraphic unit by C.S. MacRae in the late 1980s to designate the basal argillaceous (muddy) sequence of the Ecca Group within this isolated, fault-bounded basin. Lower formation in Ecca Gr in Ellisras Basin

Synonym:

Lithology and Thickness

A fine-grained, predominantly clayey basinal succession. It consists primarily of dark grey to black, thinly laminated, carbonaceous shales, mudstones, and subordinate micaceous siltstones.

Lithology Pattern:

Claystone

Relationships and Distribution

Lower contact

Conformably to disconformably overlies the glaciogenic diamictites and post-glacial mudrocks of the Waterhoutkop Fm (the local Dwyka Gr equivalent). Where the Waterhoutkop is absent due to paleotopography, it rests with a profound unconformity directly upon the Precambrian basement. This contact represents the rapid post-glacial flooding of the basin.

Upper contact

Conformably and transitionally overlain by the massive, coarse-grained sandstones and discrete coal seams of the Swartrant Fm (Middle Ecca equivalent).

Regional extent

Restricted entirely to the subsurface of the Ellisras Basin (Waterberg Coalfield) in northwestern South Africa, near the Botswana border. It is known almost exclusively from coal exploration boreholes. Lower Ecca Gr equivalent in the Ellisras Basin. It is the direct regional chronostratigraphic equivalent of the Pietermaritzburg Fm in the Main Karoo Basin.

GeoJSON

null

Fossils

Age

Early Permian (Asselian-Sakmarian)

Age Span:

Beginning stage:

Asselian

Fraction up in beginning stage:

0.1

Beginning date (Ma):

298.35

Ending stage:

Sakmarian

Fraction up in the ending stage:

0.5

Ending date (Ma):

292.02

Depositional setting

Deep-water lacustrine (lake) to expansive inland sea 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; Dreyer, J.C. (1999): The stratigraphy and sedimentation of the Vryheid Formation equivalent in the Waterberg Coalfield.