New Insights into the Geology of the Namaqua Tectonic Province, South Africa, from Ion Probe Dating of Detrital and Metamorphic Zircon

Raith, Johann; Cornell, David H.; Frimmel, Hartwig E.; Beer, C.H. de

doi:10.1086/373973

Cited by 68 publications

(30 citation statements)

References 27 publications

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“…The metamorphic history of the Bushmanland terrane can also be correlated with that of the Natal belt. An older metamorphic event has been dated at 1187 ± 15 Ma from overgrowths on 1200-1250 Ma detrital zircon grains in keeping with the 1182 ± 19 Ma age obtained from the Tugela terrane, with a younger HT-LP event dated from metamorphic rims at 1032 ± 12 Ma (Robb et al, 1999) and 1022 ± 5 Ma (Raith et al, 2003). This younger event, which took place at temperatures up to 870°C at 5 kbar, (cf.…”

supporting

confidence: 73%

“…A recent U-Pb single zircon study (Raith et al, 2003) has shown that contrary to previous assumptions, at least some of the supracrustal rocks in the southern part of the Bushmanland terrane are Mesoproterozoic in age. Detrital zircon grains from the lowermost tectono-stratigraphic part of this succession yielded dates between 1200 and 1250 Ma while meta-pelite from the top of the structural succession contains detrital zircon grains as young as 1136 ± 21 Ma (Raith et al, 2003). The timing of magmatism in the Namaqua belt is best constrained from the O'oKiep district in the northern part of the Bushmanland terrane.…”

mentioning

confidence: 71%

“…Juvenile crust has been identified in the Areachap terrane adjacent to the western margin of the Kaapvaal craton (Cornell et al, 1986;Geringer et al, 1994). In the northern part of the Bushmanland terrane to the west of the Areachap arc, however, Palaeoproterozoic (2.0-1.8 Ga) crust forms the basement to a sequence of Mesoproterozoic supracrustal rocks (Robb et al, 1999) and detrital zircon grains as old as 1.7 Ga characterise meta-pelite from the southern part of the terrane (Raith et al, 2003). In addition, a Palaeoproterozoic Andean-type magmatic arc, the Richtersveld terrane (Reid, 1997), forms a fault-bounded basement wedge along the northern margin of the Bushmanland terrane (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…This younger event, which took place at temperatures up to 870°C at 5 kbar, (cf. Margate terrane) is attributed to abnormally high heat flow due to synorogenic magmatism in an extensional regime (Raith et al, 2003).…”

mentioning

confidence: 99%

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Geology and evolution of the Natal belt, South Africa

McCourt

Armstrong

Grantham

et al. 2006

Journal of African Earth Sciences

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supporting

confidence: 73%

mentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Geology and evolution of the Natal belt, South Africa

McCourt

Armstrong

Grantham

et al. 2006

Journal of African Earth Sciences

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“…Hartnady et al, 1985;Joubert, 1986a, b;Cornell et al, 1992;2006;Gibson et al, 1996;Thomas et al, 1994;1996;Basson and Watkeys, 2003;Colliston and Schoch, 2002;Eglington and Armstrong, 2003;Raith et al, 2003;Eglington, 2006;Bailie et al, 2007;Cornell and Pettersson, 2007 and references therein).…”

Section: Mesoproterozoic Tectonic Settingmentioning

confidence: 99%

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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The O’okiep Copper District, Namaqualand, South Africa: a review of the geology with emphasis on the petrogenesis of the cupriferous Koperberg Suite

Clifford

Barton

2012

Miner Deposita

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New Insights into the Geology of the Namaqua Tectonic Province, South Africa, from Ion Probe Dating of Detrital and Metamorphic Zircon

Cited by 68 publications

References 27 publications

Geology and evolution of the Natal belt, South Africa

Geology and evolution of the Natal belt, South Africa

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

The O’okiep Copper District, Namaqualand, South Africa: a review of the geology with emphasis on the petrogenesis of the cupriferous Koperberg Suite

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