High-Mg tholeiitic rocks and their significance in the Karroo Central Province
- Eales, Hugh V, Marsh, Julian S
- Authors: Eales, Hugh V , Marsh, Julian S
- Date: 1979
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:36916 , https://hdl.handle.net/10520/AJA00382353_5039
- Description: Averages for the composition of dolerites from the Southern and Eastern Cape, and the correlative basaltic lavas of the Stormberg, are presented for major elements and 8 of the more significant trace elements. The remarkable correspondence between these averages is indicative of the uniformity in composition of the magma emplaced over a very large area.
- Full Text:
- Date Issued: 1979
- Authors: Eales, Hugh V , Marsh, Julian S
- Date: 1979
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:36916 , https://hdl.handle.net/10520/AJA00382353_5039
- Description: Averages for the composition of dolerites from the Southern and Eastern Cape, and the correlative basaltic lavas of the Stormberg, are presented for major elements and 8 of the more significant trace elements. The remarkable correspondence between these averages is indicative of the uniformity in composition of the magma emplaced over a very large area.
- Full Text:
- Date Issued: 1979
Karoo and Etendeks flood basalt provinces, southern Africa and the tectonic development of their adjacent margins:
- Marsh, Julian S, Watkeys, M K
- Authors: Marsh, Julian S , Watkeys, M K
- Date: 1996
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144868 , vital:38386
- Description: Southern Africa hosts remnants of two continental flood basalt provinces emplaced in association with fragmentation of Gondwana. The earliest is the 183 Ma Karoo Province whose relationship to continental breakup and sea floor spreading is complex. Geochemical stratigraphy, Ar-Ar Dating and palaeomagnetism indicate that Karoo mafic igneous rocks throughout Southern Africa were emplaced over a very short interval at 183 Ma.
- Full Text:
- Date Issued: 1996
- Authors: Marsh, Julian S , Watkeys, M K
- Date: 1996
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144868 , vital:38386
- Description: Southern Africa hosts remnants of two continental flood basalt provinces emplaced in association with fragmentation of Gondwana. The earliest is the 183 Ma Karoo Province whose relationship to continental breakup and sea floor spreading is complex. Geochemical stratigraphy, Ar-Ar Dating and palaeomagnetism indicate that Karoo mafic igneous rocks throughout Southern Africa were emplaced over a very short interval at 183 Ma.
- Full Text:
- Date Issued: 1996
Karoo basalts of the Springbok Flats: geochemistry and correlation
- Authors: Marsh, Julian S
- Date: 1984
- Language: English
- Type: text , abstracts
- Identifier: http://hdl.handle.net/10962/131634 , vital:36706
- Description: Karoo basalts underlie an area of about 3750 km2 of the Springbok Flats. Four boreholes were logged and sampled for detailed petrographic and chemical analysis. The Springbok Flats basalt's chemical composition is compared with those of the Sabie River Formation of the Lebombo and the Lesotho type of the Central Karoo area. Sr- and Nd- isotopic data were also used in determining the chemical composition. The study also allows the geographical extent of the incompatible element-enriched clan of Karoo Lavas to be refined.
- Full Text:
- Date Issued: 1984
- Authors: Marsh, Julian S
- Date: 1984
- Language: English
- Type: text , abstracts
- Identifier: http://hdl.handle.net/10962/131634 , vital:36706
- Description: Karoo basalts underlie an area of about 3750 km2 of the Springbok Flats. Four boreholes were logged and sampled for detailed petrographic and chemical analysis. The Springbok Flats basalt's chemical composition is compared with those of the Sabie River Formation of the Lebombo and the Lesotho type of the Central Karoo area. Sr- and Nd- isotopic data were also used in determining the chemical composition. The study also allows the geographical extent of the incompatible element-enriched clan of Karoo Lavas to be refined.
- Full Text:
- Date Issued: 1984
Rare earth element geochemistry of the Insizwa lobe of the Mount Ayliff Complex, Eastern Cape, South Africa
- Authors: Marsh, Julian S
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6736 , http://hdl.handle.net/10962/d1007548
- Description: New rare earth element (REE) data from all lithologies of the Insizwa lobe, Mount Ayliff Complex, are presented. On the basis of size and type of Eu anomaly, the geochemical subdivision of the complex as previously described is sustained and, additionally, the Top Gabbronorite of the Central Zone is shown to have formed from a magma that was compositionally distinct from other Central Zone magmas. The Basal Zone crystallized from magmas with large negative Eu anomalies probably acquired through crustal contamination. Previously recognized compositional heterogeneity in the contact rocks is also a feature of the REE. Overall, the Insizwa magmas had higher La/Sm ratios and, to a lesser extent, higher Gd/Yb ratios than Karoo basalts and appear to have no representatives in the basalt lava sequence of Lesotho.
- Full Text:
- Date Issued: 2004
- Authors: Marsh, Julian S
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6736 , http://hdl.handle.net/10962/d1007548
- Description: New rare earth element (REE) data from all lithologies of the Insizwa lobe, Mount Ayliff Complex, are presented. On the basis of size and type of Eu anomaly, the geochemical subdivision of the complex as previously described is sustained and, additionally, the Top Gabbronorite of the Central Zone is shown to have formed from a magma that was compositionally distinct from other Central Zone magmas. The Basal Zone crystallized from magmas with large negative Eu anomalies probably acquired through crustal contamination. Previously recognized compositional heterogeneity in the contact rocks is also a feature of the REE. Overall, the Insizwa magmas had higher La/Sm ratios and, to a lesser extent, higher Gd/Yb ratios than Karoo basalts and appear to have no representatives in the basalt lava sequence of Lesotho.
- Full Text:
- Date Issued: 2004
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