Whitehill Formation
Whitehill Formation | |
---|---|
Ma | |
Type | Karoo Basins |
Geologic map of Namibia with the Whitehill Formation partly cropping out in the southeastern area (orange) |
The Whitehill Formation, alternatively written as White Hill Formation and formerly known as White Band or Whitehill or White Hill Member, is a regional
The formation comprises
The Whitehill Formation of the
Description
The Whitehill Formation is an extensive Lower Permian unit, cropping out in a thin band stretching from the Western Cape in South Africa through southeastern Namibia and the Northern Cape in the north to the Eastern Cape of South Africa in the east.[1] The formation is found at the edge of the Karoo Basin at distances of 600 kilometres (370 mi) north to south and east to west.[2] The formation is part of the Karoo Supergroup, more precisely the Ecca Group, where it overlies the Prince Albert Formation and is overlain by the Collingham Formation,[3] and in the southern Karoo by the Tierberg Formation.[4]
Single zircon U-Pb SHRIMP dating yielded an age of 279.1 ± 1.5 Ma for the Uhabis River Tuff present in the upper strata of the underlying Prince Albert Formation.[5] The Khabus Tuff within the Whitehill Formation provided a weighted mean 206Pb/238U age of 280.5 ± 2.1 Ma.[6] Other authors use an estimated age for the whole formation of around 275 Ma.[7]
In the central part of the
Lithologies
The Whitehill Formation has been subdivided into two major subunits according to their weathering color in outcrops. The lower and thicker part consists mainly of bluish- to greenish-grey
A
Depositional environments
The Whitehill Formation was deposited in a shallow
From outcrops in southernmost Namibia (Aussenkjer-Noordoewer area) it became evident that the boundary between the Prince Albert and the Whitehill Formation represents the turning point from a
Correlations
The Whitehill Formation is time equivalent with the Pietermaritzburg Formation of the Waterberg Basin of southern Namibia.[18] To the north in the Karoo Basin, the shales of the Whitehill Formation are laterally equivalent with the Vryheid Formation.[19] The upper part of the formation is correlated with the Irati Formation of the Paraná and Pelotas Basins in Rio Grande do Sul, Brazil, the Black Rock Member of the Falkland Islands,[18] and with the Huab Formation in the Huab Basin of northwestern Namibia. The lower section correlates with the Palermo and Rio Bonito Formations of the Paraná Basin and the Prince Albert Formation of the Karoo.[20] The Permian sequence in the Huab Basin is much thinner than those of the Paraná and Karoo Basins.[21] The fossil assemblages of Glossopteris and Mesosaurus are known from other parts of Gondwana; the Vryheid Formation of South Africa and coal deposits of the Lower Permian in Australia.[22]
Fossil content
The Whitehill Formation has provided a variety of fossil insects, rare flora and
The following fossils have been reported from the Whitehill Formation:[24][25][26][27][28][29][30][31]
- Reptiles
- Fish
- Insects
- Flora
Economic geology
The high concentration of organic matter in the
Results from
See also
- List of fossiliferous stratigraphic units in Namibia
- List of fossiliferous stratigraphic units in South Africa
- Geology of Namibia
- Geology of South Africa
- Ganigobis Formation
- Gondwanide orogeny
References
- ^ Cole, 2014, p.4
- ^ Cole, 2014, p.15
- ^ a b Evans & Bender, 1999, p.175
- ^ Cole, 2014, p.28
- ^ Werner, 2006, p.207
- ^ Werner, 2006, p.362
- ^ Geel et al., 2013, p.259
- ^ Branch et al., 2007, p.465
- ^ Branch et al., 2007, p.475
- ^ Branch et al., 2007, p.467
- ^ Werner, 2006, p.80
- ^ Werner, 2006, p.221
- ^ Cole, 2014, p.22
- ^ Geel et al., 2013, p.258
- ^ Werner, 2006, p.99
- ^ Werner, 2006, p.383
- ^ Werner, 2006, p.377
- ^ a b Werner, 2006, p.373
- ^ Cole, 2014, p.7
- ^ Horsthemke et al., 1990, p.74
- ^ Holzförster et al., 2000, p.255
- ^ Horsthemke et al., 1990, p.69
- ^ Evans & Bender, 1999, p.177
- ^ Khabus; Hill of the Captain's House at Fossilworks.org
- ^ Modderdrift farm at Fossilworks.org
- ^ Brandhoek (Bra 111) at Fossilworks.org
- ^ Krantz Poort farm at Fossilworks.org
- ^ Kenmoore Farm at Fossilworks.org
- ^ Victoria West District at Fossilworks.org
- ^ Burghersdorp at Fossilworks.org
- ^ District of Albania, Griqualand West at Fossilworks.org
- ^ a b Evans & Bender, 1999, p.176
- ^ Geel et al., 2013, p.263
- ^ Geel et al., 2013, p.260
- ^ Cole, 2014, p.5
- ^ Cole, 2014, p.31
- ^ Geel et al., 2013, p.264
Bibliography
- Branch, Thomas; Oliver Ritter; Ute Weckmann; Reinhard F. Sachsenhofer, and Frank Schilling. 2007. The Whitehill Formation – a high conductivity marker horizon in the Karoo Basin. South African Journal of Geology 110. 465–476. Accessed 2018-08-26.
- Cole, Doug. 2014. Geology of Karoo shale gas and how this can influence economic gas recovery, 1–34. Council for Geoscience. Accessed 2018-08-26.
- Evans, Fiona J., and Patrick A. Bender. 1999. The Permian Whitehill Formation (Ecca Group) of South Africa: a preliminary review of palaeoniscoid fishes and taphonomy. Records of the Western Australian Museum Supplement 57. 175–181. Accessed 2018-08-26.
- Geel, Claire; Hans-Martin Schulz; Peter Booth; Maarten de Wit, and Brian Horsfield. 2013. Shale gas characteristics of Permian black shales in South Africa: results from recent drilling in the Ecca Group (Eastern Cape). Energy Procedia 40. 256–265. Accessed 2018-08-26.
- Holzförster, Frank; Harald Stollhofen, and Ian G. Stanistreet. 2000. Early Permian deposits of the Huab area Namibia: a continental to marine transition. Communications of the Geological Survey of Namibia 12. 247–257. Accessed 2018-08-26.
- Horsthemke, E.; S. Ledendecker, and H. Porada. 1990. Depositional environments and stratigraphic correlation of the Karoo Sequence in northwestern Damaraland. Communications of the Geological Survey of Namibia 6. 67–77. Accessed 2018-08-26.
- Wanke, Angsar. 2000. Karoo-Etendeka Unconformities in NW Namibia and their Tectonic Implications (PhD thesis), 1–114. Julius-Maximilians-Universität Würzburg. Accessed 2018-08-26.
- Werner, Mario. 2006. The stratigraphy, sedimentology, and age of the Late Palaeozoic Mesosaurus Inland Sea, SW-Gondwana - New implications from studies on sediments and altered pyroclastic layers of the Dwyka and Ecca Group (lower Karoo Supergroup) in southern Namibia (PhD thesis), 1–428. Julius-Maximilians-Universität Würzburg. Accessed 2018-08-26.
Further reading
- J. M. Anderson and H. M. Anderson. 1985. Palaeoflora of Southern Africa. Prodromus of South African Megafloras Devonian to Lower Cretaceous 1-423
- H. Geertsema and J. A. van den Heever. 1996. A new beetle, Afrocupes firmae gen. et sp. nov. (Permocupedidae), from the late Palaeozoic Whitehill Formation of South Africa. South African Journal of Science 92:497-499
- G. Gürich. 1889. Ditrochosaurus capensis - ein neuer Mesosaurier aus der Karooformation Süd-Afrikas. Zeitschrift der Deutschen Geologischen Gesellschaft 41(4):641-652
- I. R. McLachlan and A. M. Anderson. 1977. Fossil insect wings from the Early Permian White Band Formation, South Africa. Palaeontologia Africana 20:83-86
- T. Rossmann. 2000. Studien an Mesosauriern (Amniota inc sed: Mesosauridae): 2 Neue Erkenntnisse zur Anatomie, mit Berücksichtigung der Taxonomie von Mesosaurus pleurogaster (Seeley). Senckenbergiana lethaea 80(1):13-28
- H. G. Seeley. 1892. The Mesosauria of South Africa. Quarterly Journal of the Geological Society of London 48:586-604
- E. Stromer. 1914. Die ersten fossilen Reptilreste aus Deutsch-Südwestafrika und ihre geologische Bedeutung. Centralblatt für Mineralogie, Geologie und Paläontologie 1914:530-541