>Magister Scientiae - MSc / The Proterozoic Namaqua-Natal Province comprises highly deformed rocks of medium to high grade metamorphism and is bordering the Archean Kaapvaal Craton to the west, south and east in South Africa. The sector to the west of the Craton, namely the Namaqua Sector, is structurally complex and subdivided from west to east into the Bushmanland Subprovince, the Kakamas and Areachap terranes of the Gordonia Subprovince and the Kheis Subprovince. The prominent Neusberg Mountain Range, with exposures to the north and south of the Orange River in the Kakamas Terrane constitutes evidence of crustal shortening as a result of continental collision of the Namaqua Sector block with the Kaapvaal Craton during the Namaquan Orogeny. The Mesoproterozoic Korannaland Group in the Kakamas Terrane is affected by faulting, folding and shearing.

>Magister Scientiae - MSc / The group of granites on the eastern margin of the Mesoproterozoic Namaqua sector of the polydeformed and highly metamorphosed Namaqua-Natal Province of southern Africa is known as the Keimoes Suite. The suite includes mixtures of diverse rock types not belonging to a single intrusive series and so it should be subdivided into more than one intrusive suite. The exact definition, extent, distribution and petrogenesis of these granites have been poorly defined in the past, with various authors defining the suite differently due to the lack of proper geochronology and geochemical data. The exact contact between the Namaqua sector and Kaapvaal Craton together with the role of the suite to the Namaqua tectonic evolution is still unclear. The granites of the Keimoes Suite are thought to mark the contact between the Namaqua sector and the Kaapvaal Craton. This study seeks to address the above mentioned problems by making use of new geochronology, isotope, major and trace element geochemistry together with petrography. The granites of the Keimoes Suite were previously grouped based on their degree of deformation. The geochronology, undertaken as part of this study, has proven that this classification is unfounded. The degree of foliation in these granites appears to be largely controlled by the abundance of platy minerals, such as biotite and muscovite, together with the intrusion mechanism, with deformational processes, such as shearing, playing a secondary role. The geochronology, together with geochemistry has helped to redefine the previously defined Keimoes Suite so that two well defined separate suites are recognized and the third is poorly defined due to lack of more samples of that age group. The new classification or grouping of the granites of the eastern Namaqua sector allows a more detailed examination of the tectonic evolution of this region. A member of the 1225 to 1200 Ma early syn-tectonic granites, the Josling Granite, shows a strongly developed foliation and was derived from a depleted source with a relatively low continental crustal component. This granite intruded during the time of arc accretion, and is associated with, and partly responsible for the D₁ deformation and M₁ metamorphism recognized in most of the rocks of the eastern terranes of the Namaqua sector. In terms of age, the syn-tectonic granites of the Augrabies Suite extend from 1200 to 1120 Ma and were largely derived from depleted sources with variable but more substantial amounts of continental crustal components as compared to the early syn-tectonic granite. The granites of this suite intruded during the period of peak D₂ deformation with peak magmatism between 1180 - 1135 Ma, and particularly around 1150 Ma, during the peak of metamorphism (M₂) caused by, and associated with these voluminous intrusions. The Keimoes Suite can now be defined as comprising granites of late- to post-tectonic age relative to the 1.2 - 1.08 Ga Namaquan Orogeny with magmatism occurring on the western side of the Kaapvaal Craton. The 1116 to 1066 Ma Keimoes Suite intruded during the stage of the Namaquan Orogeny in which there was continued indentation of the Kaapvaal Craton into the Namaqua sector with wrenching and shearing causing the development of rifting into which the granites intruded. The Keimoes Suite granites were derived from continental crustal sources and incorporated varying degrees of depleted source components. The intrusives and extrusives of this age occured after the main collisional event between the Namaqua Sector and the Kaapvaal Craton and are associated with the D₃ deformational event, imparting the thermal conditions leading to the M₃ metamorphic event of the rocks within both the Kakamas and Areachap Terranes. The suites mark the suture between the Archean Kaapvaal Craton and the Proterozoic Namaqua sector. The compositions of the granites of the individual suites were mainly controlled by the source with the degree of partial melting exerting a major control. The proportion of entrained peritectic assemblages and accessory minerals played a major role in controlling the compositions of the granites, particularly those of the trace elements. Variations within the compositions of the same suite are due to source heterogeneities. Generally, fractionation processes played a secondary role in influencing the composition of the granites. / Council for Geoscience and National Research Foundation

>Magister Scientiae - MSc / The thesis provides a study into the main structural features of the Namaqua Region and their relation to the intrusion of the Keimoes Suite. This was achieved by producing a digitized map of the Namaqua Region structural framework using a LandSAT image and MOVE software for remote sensing. The structural framework showed an array of shear zones and fault systems which trend in a NW-SE direction. The validation of the sense of movement, location and orientation of the shear zones was done by field mapping. The general orientation of all shear zones was NW-SE. The sense of movement along the Neusspruit, Boven Rugzeer and Trooilapspan shear zones was found to be dextral strike slip movement and the Cnydas shear zone had a sinistral strike slip movement. The location of the shear zones were determined by analyzing the deviation in general foliation trend which was visualized using Rose Diagrams. The field data and the remote sensing were found to agree with the transpressive environment of the Namaqua Region. The oblique collision of the Namaqua-Natal crustal block with the Kaapvaal Craton during the orogenic event at ~1.2 Ga created a compressionalgeotectonic setting which allowed for the intrusion of the early to late syn-tectonic Keimoes Suite granites. The lateral escape of the Namaqua-Natal crustal block took place along the western margin of the Kaapvaal Craton. This was brought on by prolonged compression which resulted in the formation of a releasing bend in the Namaqua Region. This releasing bend produced the negative flower structure with dextral shear zones which facilitated the intrusion of the post-tectonic Keimoes Suite granites.