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

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.

Grantor dc:publisher.institution

Department of Geological Sciences

Year dc:date.issued

2001

Author dc:creator

• Dunn, Natalie Kirsty

Advisor dc:contributor.advisor

• Reid, David

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/4195

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/4195