Dukwi Formation

Dukwi Fm

Period:

Carboniferous, Permian

Age Interval:

Late Carboniferous-Early Permian (Moscovian- Sakmarian)

Province:
SouthAfrica-Namibia-Botswana

Type Locality and Naming

Kalahari Basin (Central), Kalahari Basin (NE). Named after the Dukwi village and wellfield area in northeastern Botswana (near the Makgadikgadi Pans / Sua Pan). It was defined primarily through borehole cores, although some marginal outcrops exist.

Synonym:

Lithology and Thickness

A classic glaciogenic sequence highly variable in thickness depending on the pre-Karoo basement topography. It typically consists of basal massive diamictites (tillites), grading upward into stratified pebbly mudstones, thinly bedded varved shales (glaciolacustrine rythmites) with dropstones, and lenses of fluvioglacial sandstones and conglomerates.

Lithology Pattern:

Glacial till

Relationships and Distribution

Lower contact

Rests with a profound regional unconformity directly upon the glacially scoured pre-Karoo basement (typically Archean rocks of the Zimbabwe Craton or Proterozoic fold belts). The basement paleotopography consists of deep glacial valleys.

Upper contact

Conformably to paraconformably overlain by the coarse-grained, feldspathic fluvio-deltaic sandstones of the Mea Fm (or directly by lower Ecca carbonaceous shales (Bori Fm) where the arkose is absent).

Regional extent

Widespread across the northern and northeastern sub-basins of the Kalahari Basin in Botswana (including the Central Kalahari, Francistown, and Sua Pan areas). Dwyka Gr equivalent. It is the direct northern/northeastern Botswana equivalent to the Malogong Fm and Khuis Fm (Gemsbok Sub-basin, southwestern Botswana) and the Dwyka Gr of the Main Karoo Basin in South Africa.

GeoJSON

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Fossils

Age

Late Carboniferous-Early Permian (Moscovian- Sakmarian), recording the local expression of the Late Paleozoic Ice Age.

Age Span:

Beginning stage:

Moscovian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

311.09

Ending stage:

Sakmarian

Fraction up in the ending stage:

0.5

Ending date (Ma):

292.02

Depositional setting

Glacial, fluvioglacial, and glaciolacustrine environments.

Depositional pattern:

Additional Information

Compiler:

From the O. Catuneanu et al. / Journal of African Earth Sciences 43 (2005) 211–253