Foredeep submarine fans and forebulge deltas: orogenic off-loading in the underfilled Karoo Basin

Catuneanu, Octavian; Hancox, P. John; Cairncross, Bruce; Rubidge, Bruce S.

doi:10.1016/s0899-5362(02)00154-9

Cited by 83 publications

(65 citation statements)

References 31 publications

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“…It is estimated that the group attained a thickness of about 3000 m in the southern part of the basin, while it is considerably thinner elsewhere in the northern part of the basin [44]. More details on the geology, stratigraphy and tectonic setting of the Karoo Basin can be found in [45][46][47][48][49][50][51][52][53][54].…”

Section: General Geology and Stratigraphymentioning

confidence: 99%

Geochemistry of sandstones and shales from the Ecca Group, Karoo Supergroup, in the Eastern Cape Province of South Africa: Implications for provenance, weathering and tectonic setting

2017

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Geochemical compositions of twenty-four sandstone and shale samples from the Ecca Group were analysed to decipher their provenance, paleoweathering conditions and tectonic setting. The shales have high Fe 2 O 3 , K 2 O, TiO 2 , Ce, Cu, Ga, La, Nb, Nd, Rb, Sc, Sr, Th and Y content more than the sandstones, whereas, sandstones are higher in SiO 2 , Hf and Zr than the shales. The positive correlations of Al 2 O 3 with other elements as well as the abundance of Ba, Ce, Th, Rb, Zn and Zr suggest that these elements are primarily controlled by the dominant clay minerals. Tectonic discrimination diagrams revealed that the sandstones and shales are mostly of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The binary plots of TiO 2 versus Ni, TiO 2 against Zr and La/Th versus Hf as well as the ternary diagrams of V-Ni-Th*10 indicate that the shales and sandstones were derived from felsic igneous rocks. A-CN-K (Al 2 O 3 -CaO-K 2 O) ternary diagram and indices of weathering (CIA, CIW and PIS) suggest that the granitic source rocks underwent moderate to high degree of chemical weathering. The CIA values range between 24.41% and 83.76%, indicating low to high weathering conditions. The CIW values for the studied sandstones and shales range from 25.90 to 96.25%, suggesting moderate to high intensive chemical weathering. ICV values for the sandstones and shales vary from 0.71 to 3.6 (averaging 1.20) and 0.41 to 1.05 (averaging 0.82), respectively. The K 2 O/Na 2 O ratios for the studied samples vary from 0.71 to 8.29, which reveal moderate to high maturity. The plot of CIA against ICV shows that most of the shales are geochemically mature and were derived from both weak and intensively weathered source rocks. The tectonic setting discrimination diagrams support passive-active continental margin setting of the provenance.

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Section: General Geology and Stratigraphymentioning

confidence: 99%

Geochemistry of sandstones and shales from the Ecca Group, Karoo Supergroup, in the Eastern Cape Province of South Africa: Implications for provenance, weathering and tectonic setting

2017

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“…Recent interpretations of the basin evolution and tectonic setting of the MKB range from: a retro-arc foreland basin (Catuneanu et al, 1998;Catuneanu et al, 2002;Veevers, 2004;Johnson et al, 2006); a transtensional foreland system created by subsidence and tilting in a strike-slip regime ); a thin-skinned fold belt that developed from collisional tectonics and distant subduction to the south (Lindeque et al, 2011), to a transient hypothetical mantle plume related model (Turner 1999). A full review of these individual models is beyond the scope of this paper and the interested reader is referred to the references above as well as Bordy et al (2005).…”

Section: Regional Tectonic Frameworkmentioning

confidence: 99%

“…A combination of supra-and sub-lithospheric loads (Pysklywec and Mitrovica, 1989;Catuneanu et al, 2002) is believed to be responsible for the observed flexural profile and generation of accommodation space.…”

Section: Regional Tectonic Frameworkmentioning

confidence: 99%

“…The present literature is split on the question of whether or not the various coal bearing successions in the MKB can be correlated, with authors such as Van Vuuren and Cole (1979), Cadle (1982), Van Vuuren (1983), Falcon (1986a, and Catuneanu et al (2002) believing that they can be, and Tavener- Smith (1983) questioning the validity of using coal seams for correlation. The senior author is of the opinion that Van Vuuren and Cole (1979) and Van Vuuren (1983) have however shown that detailed sedimentological and stratigraphic research, coupled with palynological and petrographic data, allows for informative and useful seam correlations.…”

Section: Main Karoo Basinmentioning

confidence: 99%

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South Africa's coalfields — A 2014 perspective

Hancox

Götz

2014

International Journal of Coal Geology

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Highlights• South Africa's Coalfields are presented.• The role of Gondwanan coals as palaeoclimate archives is stated.• Future research fields include palynology, sequence stratigraphy, basin fill. AbstractFor well over a century and a half coal has played a vital role in South Africa's economy and currently bituminous coal is the primary energy source for domestic electricity generation, as well as being the feedstock for the production of a substantial percentage of the country's liquid fuels. It furthermore provides a considerable source of foreign revenue from exports.Based on geographic considerations, and variations in the sedimentation, origin, formation, distribution and quality of the coals, 19 coalfields are generally recognised in South Africa. This paper provides an updated review of their exploration and exploitation histories, general geology, and coal seam nomenclature and coal qualities. Within the various coalfields autocyclic variability is the norm rather than the exception, whereas allocyclic variability is much less so, and allows for the correlation of genetically related sequences. During the mid-Jurassic break up of Gondwana most of the coals bearing successions were intruded by dolerite. These intrusions are important as they may cause devolatilisation and burning of the coal, create structural disturbances and related seam correlation problems, and difficulties in mining operations.Whilst many of the coalfields have been extensively explored and exploited, those in the north of the country have until recently received much less attention. Four coalfields occur partly or wholly within the Limpopo Province of South Africa and these may contain as much as 70% of South Africa's remaining coal resources. These coalfields in particular have been the focus of recent exploration due to the presence of large coking and thermal coal resources, as well as for their coal bed methane potential, resources that need to be unlocked regards to maximum benefit and minimal environmental degradation. South Africa's coals have been also recently addressed as palaeoclimate archives recording Gondwana's postglacial climate amelioration by major changes in land plant communities, and proving high-resolution palyno-stratigraphy as a crucial tool to decipher climate change during the Permo-Carboniferous. This aspect of the coals of South Africa is also reviewed.

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“…The depositional history of the Main Karoo retro-arc foreland basin, recorded in the Karoo Supergroup, spans from the Late Carboniferous to the Middle Jurassic (Catuneanu et al, 2002). Situated on the craton side of the Cape Fold Belt, a north verging fold and thrust belt created by subduction along the palaeopacific margin (Daly et al, 1992), the Karoo Supergroup attains a maximum thickness of 6-8 km in the south (Rubidge, 1995).…”

Section: Geological Settingmentioning

confidence: 99%

Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa

Herbert

Compton

2007

Sedimentary Geology

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The upper Dwyka and lower Ecca Groups in the Karoo Basin of South Africa document the climatic and palaeoenvironmental changes associated with the final Permo-Carboniferous deglaciation of the Gondwana supercontinent. The depositional environments of these groups have, until recently, been interpreted on the basis of sedimentological and palaeontological evidence. Here we use the geochemistry of early diagenetic concretions -septarian calcite concretions from the upper Dwyka Group and phosphatic chert concretions and beds from the lower Ecca Group -to infer the depositional environment of these rocks in the southwestern Karoo Basin. δ 18 O values (7.8 to 8.9‰ SMOW) suggest that the calcite concretions precipitated from a mixture of meteoric and glacial melt waters rather than Permian seawater. δ 13 C values (−15 to − 3‰ PDB) indicate that the carbon was derived from a mixture of craton-derived calcareous material and organic matter, bacterially degraded in the lower sulphatereduction to upper methanogenesis zones during early burial diagenesis. The rare-earth element (REE) patterns, Sr concentrations and 87 Sr/ 86 Sr ratios (0.716-0.737) significantly greater than Permian seawater (0.708), together also support the interpretation that calcite and phosphatic concretions formed in glacial, fresh water sediments.

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Foredeep submarine fans and forebulge deltas: orogenic off-loading in the underfilled Karoo Basin

Cited by 83 publications

References 31 publications

Geochemistry of sandstones and shales from the Ecca Group, Karoo Supergroup, in the Eastern Cape Province of South Africa: Implications for provenance, weathering and tectonic setting

Geochemistry of sandstones and shales from the Ecca Group, Karoo Supergroup, in the Eastern Cape Province of South Africa: Implications for provenance, weathering and tectonic setting

South Africa's coalfields — A 2014 perspective

Depositional environments of the lower Permian Dwyka diamictite and Prince Albert shale inferred from the geochemistry of early diagenetic concretions, southwest Karoo Basin, South Africa

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