The geomorphology and aeolian deposits in the vicinity of Florisbad
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Date
2011-05
Authors
Rabumbulu, Mulalo
Journal Title
Journal ISSN
Volume Title
Publisher
Univeristy of the Free State
Abstract
The discovery of the Florisbad hominid prompted further archaeological and
palaeoanthropological research in the Florisbad area. However, research that looks
specifically at the geomorphology and aeolian deposits around Florisbad has been
very limited, although aeolian processes and sand dunes have been widely
recognized as being of significance in understanding past environmental conditions
in this area. Geologists have also shown an interest in trying to explain the formation
of the Florisbad spring and fossil site. The Florisbad spring site has a complex stratigraphy because the deposits are
lithologically variable due to the fact that they are the product of an unusual
depositional environment. Many hypotheses have being proposed in trying to
understand the complex depositional environment at Florisbad. This research
suggests that, in order to better understand the complex depositional environment of
Florisbad, there is a need to understand the surrounding geomorphological setting in
terms of geohydrological and geomorphic processes and features. The methodology comprises a review of current literature on lunette dunes, and
previous work undertaken on the geomorphology and geology at and around
Florisbad, an examination of aerial photographs to identify lunette dunes in the
vicinity of Florisbad, and fieldwork to ground-truth the dunes. Field sampling,
laboratory work (sedimentological techniques, pH, conductivity and geochemical
analysis) as well as statistical analyses (principal component and cluster analyses)
were employed to compare the characteristics of the lunette dune sediments with
those at the spring site itself, and to assist in a general palaeoenviromental
reconstruction.The results of the laboratory analyses do not reveal any obvious differences with
respect to sediment particle size and pH, between the lunette dunes and the spring
site. However it was noted that there were minor differences when it came to dune
structures, electrical conductivity and chemical composition. There is convincing
evidence that the sediments are primarily wind-blown in origin. The geochemical
results suggest the lunettes are older than the dune at the spring site. Two optically
stimulated luminescence dates were determined for a lunette dune close to
Florisbad. The samples were dated to 500 years, and it is suggested that this is
because of reworking of sediments down the slope. The overall geomorphology, as described in this study, suggests a shallow
depression (Florisbad-Soutpan) in which both fluvial and aeolian processes have
conspired to create a unique landscape which has promoted the formation and
preservation of dune deposits and the unique archaeological site which is Florisbad.
Description
Keywords
Dissertation (M.A. (Geography))--University of the Free State, 2011, Geomorphology -- South Africa -- Florisbad, Sedimentation and deposition -- South Africa -- Florisbad, Sedimentary basins -- South Africa -- Florisbad