Boritse Formation

Boritse Fm

Period:

Permian

Age Interval:

Early Permian (Kungurian)

Province:
SouthAfrica-Namibia-Botswana

Type Locality and Naming

Kalahari Basin (Central). Eastern Botswana. As with most Karoo units in the Kalahari Basin, natural surface outcrops are rare, and the formation was formally defined from extensive coal exploration boreholes by the Botswana Geological Survey. Upper formation in Ecca Gr in Kalahari Basin (Central).

Synonym:

Lithology and Thickness

A highly heterogeneous, coal-bearing succession. It is characterized by alternating sequences of coarse-medium-grained feldspathic sandstones, carbonaceous mudstones, grey siltstones, and thick, economically significant coal seams.

Lithology Pattern:

Sandstone

Relationships and Distribution

Lower contact

Typically overlies the thick, arenaceous (sandy) braided-river deposits of the Kweneng Fm or the Kamakwe Fm (Middle Ecca equivalents).

Upper contact

Conformably or transitionally overlain by the non-carbonaceous, pale mudstones and siltstones of the Kwetla Fm or Tlhabala Fm (Beaufort Gr equivalents).

Regional extent

Widespread across the eastern, central, and northern sub-basins of the Kalahari Basin in Botswana. Upper Ecca Gr equivalent. It chronostratigraphically correlates with the Otshe Fm in the southwestern Gemsbok Sub-basin (Botswana) and the economically vital, coal-bearing Vryheid Fm in the Main Karoo Basin of South Africa.

GeoJSON

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Fossils

Age

Early Permian (Kungurian)

Age Span:

Beginning stage:

Kungurian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

283.30

Ending stage:

Kungurian

Fraction up in the ending stage:

1.0

Ending date (Ma):

274.37

Depositional setting

Fluvio-deltaic and expansive paludal (peat swamp) continental environments.

Depositional pattern:

Additional Information

Compiler:

From the O. Catuneanu et al. / Journal of African Earth Sciences 43 (2005) 211–253; Smith, R. A. (1984): The lithostratigraphy of the Karoo Supergroup in Botswana. Geological Survey of Botswana; Modie, B. N. (2007): The Palaeozoic palynostratigraphy of the Karoo Supergroup and palynofacies insight into palaeoenvironmental interpretations, Kalahari Karoo Basin, Botswana.