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Petrogenesis of hybrid porphyry pipes and evolution of alkaline magmas in the Kanabeam Igneous Complex, Southern Namibia

Includes bibliography. / The linear Kuboos Bremen Igneous Province (KBIP) stretches 270km from the South African Atlantic coast north-eastwards into southern Namibia, and was emplaced at approximately 500Ma. One central complex within the KBIP is the Kanabeam Igneous Complex (KIC) where practically all the rock types found in the province are represented and include nepheline syenites, quartz syenites as well as granites. In addition to these plutonic phases a number of late stage, xenolith rich porphyry pipes were emplaced, exploiting contact zones between earlier plutons. Xenolith types include gabbro possibly derived from unexposed deeper parts of the KIC, syenites (more proximal components of the KIC), trachytes from an inferred overlying volcanic edifice, basement granites, gneisses and metasediments as well as Nama Group sediments. Petrographicl examination in the porphyries has releaved that there are numerous minerals out of textual equilibrium, including olivine, pyroxene and plagioclase. Other minerals such as biotite, amphibole and alkali feldspar appear more stable.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/4195
Date January 2001
CreatorsDunn, Natalie Kirsty
ContributorsReid, David
PublisherUniversity of Cape Town, Faculty of Science, Department of Geological Sciences
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeMaster Thesis, Masters, MSc
Formatapplication/pdf

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