Postgraduate Research Thesis in Applied Geology

University: University of the Western Cape

Thesis title: Geochronology, petrogenesis and isotopic significance of the Paleoproterozoic Gladkop Suite, north-western portion of the Namaqua Sector, Namaqua-Natal Metamorphic Complex.

Student name: Mr Ansahmbom Yong Nke

Student no.: 3004335

Supervisor: Dr. Russell Bailie

Department: Earth Sciences, Applied Geology.

Abstract:

The Namaqua Metamorphic Complex formed as a result of global mid- to late- Proterozoic orogenic events during the regional 1.2-1.0 Ga Namaquan Orogeny. The pink and grey gneisses of the Gladkop Suite (Van Aswegen, 1983) occur in the north-western portion of the Namaqua Metamorphic Complex and predate the Namaquan Orogeny forming a “basement” to the younger supracrustal successions and emplacement of granitic gneisses. Based on their composition, the orthogneisses of the Gladkop Suite are divided into three major gneiss units, namely the Steinkopf Gneiss, the Brandewynsbank Gneiss and the Noenoemaasberg Gneiss (Van Aswegen, 1983). These gneiss units exhibit intrusive relationships, with each progressively intruding the other (Van Aswegen, 1983). A detailed description of the Gladkop Suite is provided by Van Aswegen (1983) while Robb et al. (1999) provided zircon ²⁰⁷Pb/²⁰⁶Pb ages for the Brandewynsbank Gneiss: magmatic zircon: ~1822±36Ma, xenocrystic zircon: ~2018±8Ma and zircon rim: ~1032±18Ma. However, the Steinkopf Gneiss which represents the major lithological unit, and the Noenoemaasberg Gneiss have not been dated.

This study will provide emplacement and metamorphic ages for both the Steinkopf and Noenoemaasberg Gneiss units. The geochemistry of the Gladkop Suite will be examined with the aim of obtaining the characteristics and origin (petrogenesis) of the orthogneisses. Isotope analyses will also be carried out to determine their source. This information obtained will be used to determine the role of the Gladkop Suite in the development of the Namaqua-Natal Metamorphic Province.

References

Robb, L. J., Armstrong, R. A. & Waters, D. J. (1999). Nature and duration of mid-crustal granulite-facies metamorphism and crustal growth: evidence from single zircon U-Pb geochronology in Namaqualand, South Africa. Journal of Petrology 40, 1747–1770.

Van Aswegen, G. (1983). The Gladkop Suite – the grey and pink gneisses of Steinkopf. Spec. Publ. geol. Soc. S. Afr. 10, 31-44.

The Funds will be used to carry out laboratory analyses which are quite expensive and for the trips to and from my study area. I work part-time, but the money I get from waitering is just enough to pay for my tuition and accomodation.

Thanks for your support.