Tectonics

The Tectonics Subdivision is concerned with the stratigraphy and structural-metamorphic aspects of the oldest rocks found in Namibia, i.e. the Palaeo – to Neoproterozoic orogenic belts. A simplified tectonostratigraphic map showing the major tectonic and stratigraphic domains of the country is available and can be downloaded here

Current Mapping / Research Activities
Huab Metamorphic Complex, Khoabendus Group & Fransfontein Granite Suite

This project, which encompasses the stratigraphy, petrology, geochronology and metamorphic history of the Palaeoproterozoic Kamanjab Inlier west of Outjo, started in 2000 with the mapping of the southernmost outcrops of the Huab Metamorphic Complex and has been ongoing since. Hatched areas as indicated, are areas mapped since the beginning of the project. Petrographic and whole rock geochemical analyses of the Fransfontein granites and Khoabendus Group felsic volcanic rocks were conducted in order to better constrain the plate tectonic framework during deposition. The Fransfontein Suite has granitic compositions and high contents of rare earth elements. Petrographic and trace element compositions indicate that they are probably I-type felsic rocks. The apparent continental-arc chemistry of the granitoid and felsic volcanic rocks is probably derived from calc-alkaline sources. The Fransfontein granites and Khoabendus felsic volcanics have trace element features (e.g. Nb–Ta depletion), which indicate their emplacement in a convergent margin setting. The MORB-normalized spider diagrams exhibit a fractionated LILE/HFSE pattern recognized in subduction zones.

In addition to petrographic and whole rock geochemical analyses, structural analysis, determination of the genesis of the fluid system, and an evaluation of the tectono-metamorphic history of the Khoabendus Group was carried out, within the framework of three B.Sc. Honours theses entitled “The geology of the Khoabendus Group in Northwestern Namibia”, “Mineralization in the northern part of the Khoabendus Group (northwestern Namibia)” and “Petrology and Geochemistry of the Khoabendus Group and the Fransfontein Suite in the Kamanjab Area (Northwestern Namibia)”, which are available at the National Energy and Earth Sciences Information Centre - NESEIC - at the Geological Survey.

Stratigraphy

The Stratigraphy Subdivision deals with the stratigraphy, sedimentology and palaeontology of the younger Palaeozoic to Cenozoic sedimentary basins, including offshore basins

Current mapping/research activities

Ongoing mapping project of Quaternary to Recent surficial sediments of the Central Namib Uranium District, within the Walvis Bay sheet. The locations are selected with the help of  ASTER mineral maps and HyVista hyperspectral mineral products, based on spectral mineralogical criteria..

 The project aimed at mapping previously undifferentiated Quaternary surficial sediments in the study area by means of integrated GIS and remote sensing techniques in tandem with field verification. Results of this project will provide important new geological baseline data of the composition, age, distribution and provenance of uranium-hosting sediments, as well as factors controlling the localisation and origin of the secondary uranium mineralization, and on the environmental monitoring of uranium exploration and mining.

Below is the part of the study area showing previously undifferentiated Quaternary surficial sediments (published  map, left) and interpreted, new regolith units for the inland area (right). The inland site is dominated by alluvial cover sediments and here the regolith is transported SW, mainly by fluvial systems.

GIS & Remote Sensing

Whose task it is to convert field and archival map data into digital format, assess and compile information from various sources to produce digital maps, and employ such remote sensing techniques as are available to improve existing field data.

The GIS & Remote Sensing Subdivision’s task is the capture and compilation of field data acquired by Geological Survey staff or obtained from outside agencies, maintenance of the geological map data base, as well as the analyses of digital geological data for the production of thematic maps and reports. The subdivision also deals with remote sensing in geological mapping, making use of aerial photographs, orthophotos, satellite images and hyperspectral data, which are especially useful for this purpose in arid regions, with little or no vegetation cover.