Abstract
The Joostenberg kaolin deposit is a residual clay overlying Malmesbury Group strata and is located on the farm Joostenberg Vlakte 724, some 12 km northeast of Bellville. By means of field observations and inference derived from the chemical analyses of clay and its precursor rock types, it is suggested that this deposit, which is suitable for brick making, formed as a result of two independent geological processes. The intrusion of the approximately 550 to 510 Ma syn- to post tectonic granitoids of the Cape Granite Suite into micaceous, feldspathic shale of the Malmesbury Group created a hydrothermal vein structure. These veins developed along pre-existing zones of weakness such as fault or shear zones. Hydrothermal fluids migrating along these fractures were initially dominated by magmatic water and later by meteoric or seawater. The hydrothermal fluids were also responsible for extensive alteration of the surrounding shale but the original rock fabric survived. The second geological process comprised a phase of in-situ weathering between the Cretaceous and Neogene Periods, resulting in the development of a deep soil profile and the formation of an iron-rich layer (ferricrete) at surface.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.