The Cape Basin, South Africa: A review

Shone, R. W.; Booth, P. W. K.

doi:10.1016/j.jafrearsci.2005.07.013

Cited by 59 publications

(36 citation statements)

References 21 publications

(49 reference statements)

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“…The regional geology of the southern Karoo Basin and CFB are well documented and not described in detail here (e.g. Hälbich 1983a, b, c;Söhnge and Hälbich, 1983;de Wit and Ransome, 1992;Hälbich, 1993;Thomas et al, 1993;Veevers et al, 1994;Johnson et al, 1996;2006;Shone and Booth, 2005). Table 1 and Figure 2 summarise the stratigraphy compiled from the geological field maps (CGS, 2000) and nearby boreholes SA-1/66 and KW-1/67 (PASA, 1966;1967b).…”

Section: Introductionmentioning

confidence: 98%

Deep Crustal Profile Across the Southern Karoo Basin and Beattie Magnetic Anomaly, South Africa: An Integrated Interpretation With Tectonic Implications

Lindeque

Wit

Ryberg

et al. 2011

South African Journal of Geology

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Two geophysical onshore-offshore lines on the southern margin of Africa form the Agulhas-Karoo Geophysical Transect (AKGT) and cross prominent geological features such as the Karoo Basin, Cape Fold Belt (CFB) and the Beattie Magnetic Anomaly (BMA). Geophysical data acquired along this AKGTransect between 2004 and 2007 within the Inkaba yeAfrica (lyA) framework, provide the platform for constructing a deep crustal section (IyA-200501) for the centre 100 km of the western AKGT-transect in order to resolve these features at depth. We present a detailed deep crustal model constructed from the joint interpretation of: i. archive data comprising surface geology, aeromagnetic data, nearby deep boreholes, teleseismic receiver functions and regional seismic reflection profiles, and ii. line coincident newly acquired high-resolution geophysical data consisting of near vertical seismic reflection data, shallow P-and S-wave velocity data, wide-angle refraction data, high resolution magnetotelluric data and impedance spectroscopy measurements on borehole samples. Our model differentiates four components in the up to 45 km thick crust: 1. a ~2 to 5 km thick folded Karoo Supergroup, disrupted by low-angle thrust faults rooted in a zone of local décollements in the lower Ecca Group and resting paraconformably on 2. a continuous undeformed sub-horizontal ~1.5 to 10 km thick wedge of the Cape Supergroup (CSG). This CSG wedge stretches from the Escarpment in the north to the tectonic front of the CFB in the south, and rests on an unconformity that dips about three degrees to the south. The angular unconformity is interpreted as an erosional peneplain that separates the CSG wedge from component 3. the ~13 to 21 km mid-crust basement below. The mid-crust contains a distinct north-dipping seismic fabric, here interpreted as 1.4 to 1.0 Ga Mesoproterozoic Namaqua-Natal Metamorphic Belt (NNMB) crust. A south-dipping mid-crustal detachment, interpreted as a ductile thrust zone, separates the mid-crust from component 4. a highly reflective ~10 to 24 km thick lower crust. The latter is interpreted as an older Palaeoproterozoic section of the NNMB (or even Archean cratonic basement), and bounded by a ~2 to 5 km thick, highly reflective bottom layer below that lies subparallel to a clear Moho. This bottom layer is interpreted as a mafic underplate, metasomatic reaction zone, or lower-crust to mantle transition zone. Collectively the seismic reflection and wide-angle refraction data support an interpretation that the NNMB mid-crustal layer contains the BMA source, possibly connected to two zones of strong reflectivity: a ~10 to 12 km wide northern zone and a ~5 to 7 km wide southern zone, both about 5 km thick and 7 to 8 km below surface. We interpret the BMA source to be at least in part, a Namaqua-like massive to disseminated, deformed/metamorphosed stratiform sulphide-magnetite ore body with metasomatic overprint.

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Section: Introductionmentioning

confidence: 98%

Deep Crustal Profile Across the Southern Karoo Basin and Beattie Magnetic Anomaly, South Africa: An Integrated Interpretation With Tectonic Implications

Lindeque

Wit

Ryberg

et al. 2011

South African Journal of Geology

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“…In the Early Palaeozoic (Cambrian-Silurian), sediments of the Cape Supergroup were deposited along a passive continental margin during a period of extensional tectonism. Sedimentation continued into the Late Palaeozoic (Devonian-Carboniferous) and was followed by deposition of the Permo-Triassic Karoo sediments (Hälbich 1983(Hälbich , 1992Shone and Booth 2005). Tectonic inversion took place towards the end of the Palaeozoic.…”

Section: Geological Settingmentioning

confidence: 99%

Geothermal energy from the Main Karoo Basin? New insights from borehole KWV-1 (Eastern Cape, South Africa)

2016

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“…De Wit and Ransome (1992) synthesized the belt's inversion tectonics and de Beer (1992) and Booth (2009) reviewed its structural geology and structural evolution. Despite all these studies the structure and evolution of the CFB is a matter of considerable debate among geologists (see Booth, 2011;de Wit and Ransome, 1992;Shone and Booth, 2005;Shone et al, 1990) and the belt still lacks fully integrated studies (Mielke and de Wit, 2009).…”

Section: Regional Tectonic Settingmentioning

confidence: 99%

“…Various detailed descriptions of the styles of deformation of the Cape Supergroup rocks have been presented by various authors, particularly in the Eastern Cape (e.g. Booth and Shone, 2002;Shone and Booth, 2005). Only a brief summary is presented below.…”

Section: Geological Deformation In the Cfbmentioning

confidence: 99%

Structural control of fluvial drainage in the western domain of the Cape Fold Belt, South Africa

Manjoro

2015

Journal of African Earth Sciences

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The Cape Basin, South Africa: A review

Cited by 59 publications

References 21 publications

Deep Crustal Profile Across the Southern Karoo Basin and Beattie Magnetic Anomaly, South Africa: An Integrated Interpretation With Tectonic Implications

Deep Crustal Profile Across the Southern Karoo Basin and Beattie Magnetic Anomaly, South Africa: An Integrated Interpretation With Tectonic Implications

Geothermal energy from the Main Karoo Basin? New insights from borehole KWV-1 (Eastern Cape, South Africa)

Structural control of fluvial drainage in the western domain of the Cape Fold Belt, South Africa

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