Exploring relationships between geological structures delineated from high resolution geophysical data collected over 1:50,000 mapsheets 2229AB Mapungubwe and 2229AD Coila, Beit Bridge Terrane, Central Zone, Limpopo Belt, South Africa
Date
2014-03-05
Authors
Havenga, Marinda
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
High resolution aeromagnetic and radiometric data covering the 1:50,000 mapsheets
2229AB Mapungubwe and 2229AD Coila were collected by the Council for Geoscience
and interpreted in this study. Several generations of magnetised lineaments were
identified and modelled as mafic dykes. North-northwest, east-northeast and east-west
trending lineaments occur in the pre-Karoo basement (~2.04 Ga to Dwyka) and east-west
trending lineaments predominate in Karoo sediments (<183 Ma).
A number of circular magnetic anomalies occur in north-northwest and east-northeast
trending clusters in the southwest of the study area. These were interpreted to be
intrusive plugs – possibly feeders for the dolerite sills and dykes that occur in the area.
Radiometric data delineate geological units within the pre-Karoo basement. Granitic to
granodioritic rocks (2.6 Ga) are enriched in uranium and thorium while tonalitic rocks are
not.
Geological cross-sections, constructed along flight lines and tie-lines, suggest that there
are two or more sills at depth under the southwestern portion of the study area intruded
by the Venetia kimberlite pipes. In addition a large strongly magnetic anomaly with no
surface expression was identified in the northeastern area and modelled to be at about
1200 m depth.
Description
Thesis (M.Sc.)--University of the Witwatersrand, Faculty of Health Sciences, 2013.