Abstract
The Buffels River Complex is located in the Northern Cape Province between the towns of Springbok
and Kleinzee. Mining of the diamondiferous gravels of the Buffels River Complex have taken place
over the last 50 years. During this time very little scientific work has been conducted on the deposit,
except for an internal unpublished report by Myburgh (2004) for De Beers. The age of deposition as
well as the source regions of the diamonds are unknown. Understanding the age of deposition of the
sediments of the Buffels River Complex as well as the source regions will give insight into the
development of the coastal hinterlands after the breakup of Gondwana. Using the current
understanding of the landscape evolution after the breakup of Gondwana and comparing it to the
Buffels River Complex, a better understanding of the deposit can be made. Attaining the objectives
above required field work of the Buffels River complex, U/Pb detrital zircon provenance studies on
the different sedimentary units of the BRC as well as 40Ar - 39Ar age determination of Mnoxyhydroxide
crusts.
Field work on the Buffels River Complex, relating the erosional surfaces and accompanying
stratigraphy with that of the known landscape evolution, focusing on the formation of the landsurfaces
after the breakup of Gondwana indicated that the Buffels River Complex did indeed form after the
breakup of Gondwana. This was based on similarities between the paleoenvironments as well as the
depositional environments during the formation of the Post African 1-and Post African 2 landsurfaces
and the sediments of the Buffels River Complex.
40Ar – 39Ar age determination of the Mn-oxyhydroxide crusts related to the formation of the erosional
surfaces found in the stratigraphy of the Buffels River Complex were unsuccessful, producing only
near plateaus and staircase patterns. These patterns indicated that multiple K-bearing phases are
present in the samples. The release patterns produced very old ages ranging from early Cambrian to
late Silurian. This indicates that the ages obtained most likely where produced from K–baring detrital
mineral phases present in the Mn-oxyhydroxide crusts and not related to the formation of the Mnoxyhydroxide
crusts.
U/Pb provenance studies of the detrital zircon grains obtained from the different units of the Buffels
River Complex produced a wide range of detrital zircon ages ranging from Archean to Cambrian.
The absence of younger ages which is observed within the Karoo Supergroup indicates that the
Buffels River Complex must have formed from a restricted source area which did not contain any
Karoo Supergroup rocks.
M.Sc. (Geology)