Petrology and geochemistry of Early Cretaceous bimodal continental flood volcanism of the NW Etendeka, Namibia Part 1: introduction, mafic lavas and re-evaluation of mantle source components
- Authors: Ewart, A , Marsh, Julian S , Milner, Simon C , Duncan, Andrew R , Kamber, B S , Armstrong, R A
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150583 , vital:38986 , https://doi.org/10.1093/petrology/egg083
- Description: The bimodal NW Etendeka province is located at the continental end of the Tristan plume trace in coastal Namibia. It comprises a high-Ti (Khumib type) and three low-Ti basalt (Tafelberg, Kuidas and Esmeralda types) suites, with, at stratigraphically higher level, interstratified high-Ti latites (three units) and quartz latites (five units), and one low-Ti quartz latite. Khumib basalts are enriched in high field strength elements and light rare earth elements relative to low-Ti types and exhibit trace element affinities with Tristan da Cunha lavas.
- Full Text: false
- Date Issued: 2004
Petrology and geochemistry of early cretaceous bimodal continental flood volcanism of the NW Etendeka, Namibia Part 2: characteristics and petrogenesis of the high-Ti latite and high-Ti and low-Ti voluminous quartz latite eruptives
- Authors: Ewart, A , Marsh, Julian S , Milner, Simon C , Duncan, Andrew R , Kamber, B S , Armstrong, R A
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150593 , vital:38987 , https://doi.org/10.1093/petrology/egg082
- Description: As a result of their relative concentration towards the respective Atlantic margins, the silicic eruptives of the Paraná (Brazil)–Etendeka large igneous province are disproportionately abundant in the Etendeka of Namibia. The NW Etendeka silicic units, dated at ∼132 Ma, occupy the upper stratigraphic levels of the volcanic sequences, restricted to the coastal zone, and comprise three latites and five quartz latites (QL).
- Full Text: false
- Date Issued: 2004
MORB-related dolerites associated with the final phases of Karoo flood basalt volcanism in southern Africa.
- Authors: Duncan, Andrew R , Armstrong, R A , Erlank, Anthony J , Marsh, Julian S , Watkins, R T
- Date: 1990
- Language: English
- Type: text , conference paper
- Identifier: http://hdl.handle.net/10962/143299 , vital:38222 , https://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetailampidt=6938249
- Description: The Rooi Rand dyke swarm is approximately 200km long and up to 20km wide. It crops out in the southern portion of the Lebombo monocline where the dykes intrude basalts of the Sabie River Basalt Formation which is the major basaltic unit in the eastern portion of the Karoo volcanic succession. The Horingbaai dolerites form thin dykes and sills which intrude the base of the Etendeka lava pile (considered part of the Karoo Volcanics, but correlated with the Serra Geral Formation of Brazil) along the coast of Namibia. Both the Rooi Rand and Horingbaai magma types are similar in composition to enriched MORB and are compositionally distinct from most of the Karoo-basalts they intrude.
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- Date Issued: 1990
Strontium isotope characterization of Karoo volcanic rocks
- Authors: Bristow, J W , Allsopp, H L , Erlank, Anthony J , Marsh, Julian S , Armstrong, R A
- Date: 1984
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/134176 , vital:37081 , https://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetailamp;idt=6453595
- Description: Karoo volcanics of both mafic and felsic composition cover large areas of southern Africa, and are characterized by considerable ranges in their initial 87Sr/86Sr (i.e. Ro) ratios. Mafic volcanics from the eastern and western continental margins show the greatest range in Ro ratios, i.e. Lebombo-Nuanetsi area: 0.7035-0.7134 and Etendeka: 0.7030-0.7135 respectively. In the Central Karoo area the mafic rocks show a smaller spread of ratios: 0.7046-0.7094.
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- Date Issued: 1984