Karoo super group
The Karoo supergroup is a lithostratigraphic structural unit in Africa . It is made up of several sedimentary basins that occur mainly south of the equator .
Definition
The geological term "Karoo" was initially limited to the sedimentary structures of the Karoo Basin in South Africa. This was used to describe continental sediments that extend beyond the Karool landscape . As knowledge progressed, the term was mainly applied to all continental sediments that emerged from the extensional basin structures of Gondwana . Similar sedimentary basins from the Upper Carboniferous to the Jura have also been found in India, Antarctica and Australia.
geology
The Karoo supergroup comprises a succession of sediments formed over 100 million years. The thickness of the deposits in individual cases exceeds 10,000 meters. The Karoo supergroup is having a major impact on the landscape in many African countries.
The first sediment formation within this supergroup began in the Carboniferous , about 300 million years ago, with the glacial deposits of the Dwyka Group. It was followed by marine sediments in the period of the Ecca Group (Ecca Group). Later fluvial sediments of the Beaufort Group and Stormberg Group were deposited over it . In the most recent section (Drakensberg Formation) of the Karoo period, lava effusions penetrated and covered the existing sediments. The most important evidence of this Plutonic activity are the Drakensberg in Lesotho and South Africa . This concludes the Karoo super group in the Jura .
Typical rocks include sandstones , siltstones , slate clays and tillites . Tectonic activities have created magmatic intrusions in some basin structures, which are among the most recent formations in the Karoo supergroup. The Karoo dolerites are best known in southern Africa. In the Lebombo Mountains , the common border area of South Africa and Mozambique , however, basalts , rhyolites , tuffs and ignimbrites occur.
Large structures
Important individual pelvic structures are:
- Aranos Basin ( Namibia , Botswana )
- Barotse Basin ( Zambia )
- Cabora Bassa Basin ( Zimbabwe , Mozambique )
- Diego Basin ( Madagascar )
- Duruma Basin ( Kenya )
- Elisras Basin (South Africa, Botswana)
- Huab Basin (Namibia)
- Kalahari Basin (Botswana, Namibia)
- Karasburg Basin (Namibia)
- Karoo main basin (South Africa, Lesotho)
- Congo Basin ( Democratic Republic of the Congo )
- Lebombo Basin (South Africa, Swaziland , Mozambique)
- Luangwa Basin (Zambia)
- Lukusashi Basin (Zambia)
- Majunga Basin (Madagascar)
- Mana Pools Basin (Zimbabwe)
- Metangula Basin ( Tanzania , Mozambique)
- Mid-Zambezi Basin (Zimbabwe, Botswana)
- Morondava Basin (Madagascar)
- Nuanetsi Basin (Mozambique)
- Owambo Basin (Namibia)
- Ruhuhu Basin (Tanzania, Malawi)
- Sava Basin (Zimbabwe)
- Selous Basin (Tanzania)
- Springbok Flats Basin (South Africa)
- Tanga cymbals (Tanzania)
- Tshipise Basin (South Africa, Zimbabwe)
- Tuli Basin (Zimbabwe)
- Waterberg Basin (Namibia)
- unnamed basin ( Angola )
Individual evidence
- ↑ JJ Lambiase: The framework of African rifting during the Phanerozoic . In: Journal of African Earth Sciences (8) 1989, pp. 183-190
- ^ Nick Norman, Gavin Whitefield: Geological Journeys . Cape Town (Struik Publishers) 2006, p. 166 ISBN 1-77007-062-1
Web links
- D. Adelmann, K. Fiedler: Sedimentary development of the Upper Ecca and Lower Beaufort Groups (Karoo Supergroup) in the Laingsburg subbasin (SW Karoo Basin, Cape Province / South Africa). Series of publications by the German Geological Society, Vol. 1, 88–89, 1996
- O. Catuneanu, H. Wopfner, PG Eriksson et al .: The Karoo basins of south-central Africa. In: Journal of African Earth Sciences, Vol. 43, pp. 211-253, 2005 (pdf, 3 MB)
- Igneous and metamorphic petrology - first term field trip to the Lower Orange River Region - Photo Gallery. ( Memento of September 8, 2010 in the Internet Archive ) Images of South African geology, Department of Geological Sciences, University of Cape Town (English)
- 3.8 Ga Earth History of South Africa - March 24 & 28, 2006 - Karoo 1 ( Memento from June 12, 2007 in the Internet Archive ) Excursion of the Geological Faculty of the University of Würzburg to South Africa (German)
- Map of the Karoo lava fields in southern Africa (pdf) (145 kB)
- Karoo supergroup in Botswana
- Karoo supergroup in Angola (PDF file; 39 kB)
- Context and history of study of the Malawi Karoo Detail thereof summary in German
- Florian Heinrich. Bremer: Karoo Rifting in the Morondava Basin, Madagascar (Dissertation TU Berlin 2005, 193 pages) (PDF file; 8.97 MB)
- geological overview map and description of Tanzania
- Geology of Zambia