The development and evolution of Etosha Pan, Namibia
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Date
2005
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Publisher
University of Wurzburg
Abstract
This study explores and examines the geomorphology of a large endorheic basin,
approximately twice the size of Luxemburg, situated in the Etosha National Park, Namibia. The main focus is directed on how and when this depression, known as Etosha Pan, came into being. The opposing view emerged in the 1980s and gained
prominence in the 1990s. This view assumed that there were an innumerable number of small pans on the then surface of what later to become Etosha Pan.
Since the turn of the Pliocene to Early Pleistocene, these individual pans started to experience a combined effect of fluvial erosion during the rainy season and wind deflation during the dry period. The climatic regime during that entire period was
postulated to be semi-arid as today. This climatic status was used to rule out any existence of a perennial lake within the boundary of Etosha since the Quaternary. Ultimately, these denudational processes, taking place in a seasonal rhythm, caused the individual pans to deepen and widen laterally into each other and formed a super-pan that we call Etosha today. Thus the Kunene River had no role to play in the development of the Etosha Pan according to this model. However, proponents of this model acknowledged that the Kunene once fed into the
Owambo Basin and assigned the end of the Tertiary to the terminal phase of that inflow. Geomorphological investigation was complemented and guided primarily by the application and interpretation of satellite-derived information. Etosha Pan has attracted scientific investigations for nearly a century. Unfortunately, their efforts resulted into two diverging and mutually exclusive views with respect to its development. The first and oldest view dates back to the 1920s. It hypothesized Etosha Pan as a desiccated palaeolake which was abandoned following the river capture of its major fluvial system, the Kunene River. The river capture was
assumed to have taken place in the Pliocene/Early Pleistocene. In spite of the absence of fluvial input that the Kunene contributed, the original lake was
thought to have persisted until some 35 ka ago, long after the Kunene severed its ties with the basin. The current size of the basin and its playa status was
interpreted to have resulted from deteriorating climatic conditions. The opposing view emerged in the 1980s and gained prominence in the 1990s. This view assumed that there were an innumerable number of small pans on the then surface of what later to become Etosha Pan. Since the turn of the Pliocene to Early Pleistocene, these individual pans started to experience a combined effect of fluvial erosion during the rainy season and wind deflation during the dry period. The
climatic regime during that entire period was postulated to be semi-arid as today. This climatic status was used to rule out any existence of a perennial lake within the boundary of Etosha since the Quaternary. Ultimately, these denudational processes, taking place in a seasonal rhythm, caused the individual pans to deepen and widen laterally into each other and formed a super-pan that we call
Etosha today. Thus the Kunene River had no role to play in the development of the Etosha Pan according to this model. However, proponents of this model
acknowledged that the Kunene once fed into the Owambo Basin and assigned the end of the Tertiary to the terminal phase of that inflow.
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Keywords
Cuvelai, Etosha Pan, Evolution