Drakensberg Gr

Period:

Jurassic

Age Interval:

Middle Jurassic (Toarcian)

Province:
SouthAfrica-Namibia-Botswana

Type Locality and Naming

Main Karoo Basin (Eastern/Northern Forebulge), Tuli Basin, Save Basin. Named after the spectacular Drakensberg mountain range (uKhahlamba), which forms the great eastern escarpment of South Africa and the high plateau of Lesotho. The entire upper elevations of this mountain range are composed of these basalts.

Synonym: Karoo Volcanics; Stormberg Lavas, Basalt Fm (Tuli Basin, Save Basin)

Lithology and Thickness

A massively thick succession of subaerial, tholeiitic continental flood basalts.

Lithology Pattern:

Lava

Relationships and Distribution

Lower contact

Conformably to paraconformably overlies the massive aeolian desert sandstones of the Clarens Fm.

Upper contact

Unconformably forms the modern erosional surface (the high plateau of Lesotho and the peaks of the Drakensberg escarpment).

Regional extent

Dominates the high-altitude topography of Lesotho and the surrounding bordering provinces of South Africa (KwaZulu-Natal, Free State, Eastern Cape). The feeder systems for these lavas form a massive network of dolerite dykes and sills that intrude the entire underlying Karoo Supergroup across much of South Africa. It is the direct regional chronostratigraphic equivalent of the Batoka Basalt Fm (Zambezi Basin), Stormberg Lava Gr (Kalahari Basin), the Kalkrand/Hoachanas basalts (Namibia), and the Letaba Fm (Lebombo Group, partly).

GeoJSON

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Fossils

Age

Middle Jurassic (Toarcian)

Age Span:

Beginning stage:

Toarcian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

184.20

Ending stage:

Toarcian

Fraction up in the ending stage:

0.2

Ending date (Ma):

182.30

Depositional setting

Continental flood basalts (Large Igneous Province).

Depositional pattern:

Additional Information

Compiler:

From the O. Catuneanu et al. / Journal of African Earth Sciences 43 (2005) 211–253; Marsh, J.S., et al. (1997): Stratigraphy and age of Karoo basalts of Lesotho and implications for correlations within the Karoo igneous province; Johnson, M.R., et al. (2006): Sedimentary rocks of the Karoo Supergroup. In: The Geology of South Africa.