Greenwich Formation

Greenwich Fm

Period:

Triassic

Age Interval:

Late Triassic (Carnian-Norian)

Province:
SouthAfrica-Namibia-Botswana

Type Locality and Naming

Ellisras Basin, Waterberg Coalfield (Limpopo Province, South Africa). Named after the farm Greenwich in the Ellisras (now Lephalale) district of the Limpopo Province. It was formally established as a lithostratigraphic unit within the isolated Ellisras Basin during comprehensive coal exploration and stratigraphic correlation efforts in the late 20th century. Lowermost formation in Stormberg Gr

Synonym:

Lithology and Thickness

A predominantly arenaceous (sandy), high-energy clastic succession. It consists largely of medium- to coarse-grained, cross-bedded sandstones, which frequently become pebbly and conglomeratic at the base.

Lithology Pattern:

Sandy_claystone

Relationships and Distribution

Lower contact

Rests with a sharp, distinct regional unconformity upon the fine-grained, brightly colored mudstones of the Eendragtpan Fm (the local Beaufort Group equivalent).

Upper contact

Conformably and transitionally overlain by the fine-grained, massive red mudstones of the Lisbon Fm (Elliot Fm equivalent).

Regional extent

Geographically restricted to the subsurface of the Ellisras Basin (Waterberg Coalfield) in northwestern South Africa. Because the basin is heavily mantled by Cenozoic Kalahari sands, the Greenwich Formation is known almost exclusively from coal exploration boreholes. Stormberg Gr (basal unit in the Ellisras Basin). It is the direct regional chronostratigraphic equivalent of the Molteno Fm in the Main Karoo Basin.

GeoJSON

null

Fossils

Age

Early Triassic (Carnian-Norian)

Age Span:

Beginning stage:

Carnian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

237.00

Ending stage:

Norian

Fraction up in the ending stage:

0.6

Ending date (Ma):

214.36

Depositional setting

High-energy continental braided river environments.

Depositional pattern:

Additional Information

Compiler:

From the O. Catuneanu et al. / Journal of African Earth Sciences 43 (2005) 211–253; MacRae, C.S. (1988): Palynostratigraphic correlation between the Lower Karoo Sequence of the Waterberg and Pafuri coal-bearing basins and the Hammanskraal plant macrofossil locality; Johnson, M.R., et al. (2006): Sedimentary rocks of the Karoo Supergroup. In: The Geology of South Africa.