The Development and Evolution of Etosha Pan, Namibia Dissertation zur Erlangung des naturwissenschaftlichen Doktorgrades der Bayerischen Julius-Maximilians-Universität Würzburg Vorgelegt von Martin HT Hipondoka Würzburg 2005 To the demise of the Bantu Education System Table of Contents Table of Contents.................................................................................................................. ii List of Figures...................................................................................................................... iii List of Tables.........................................................................................................................iv Acknowledgments..................................................................................................................v Abstract .................................................................................................................................vi Ausführliche Zusammenfassung...................................................................................... vii 1. Introduction ................................................................................................ 1 1.1 Background..........................................................................................................1 1.2 Aims and Objectives of the Study......................................................................1 2. Methods and Techniques ............................................................................. 4 2.1 Remote Sensing (RS) ..........................................................................................5 2.2 Fieldwork .............................................................................................................9 2.3 Laboratory..........................................................................................................11 2.4 Geographical Information System (GIS) .........................................................12 3. Background Setting ..................................................................................................13 3.1 Location of the Study Area ...............................................................................14 3.2 Geology ..............................................................................................................15 3.2.1 Pre-Kalahari Geology ..............................................................................16 3.2.2 Structural, Sedimentary and Geomorphological Development of the Kalahari Basin .........................................................................................19 3.2.3 The Kalahari Sequence of the Owambo Basin ..........................................21 3.3 Drainage Evolution............................................................................................26 3.1.1 The Okavango System .............................................................................27 3.3.1.1 Lake Palaeo-Makgadikgadi .........................................................................29 3.3.1.2 The Makgadikgadi Pans ..............................................................................31 3.3.1.3 The Okavango Swamps ...............................................................................34 3.4 Climate of the Study Area.................................................................................38 3.5 Soils ....................................................................................................................40 3.6 Vegetation..........................................................................................................42 3.7 Land use.............................................................................................................44 4. The Kunene River and the Catchment of Etosha Pan ..................................47 4.1 The Kunene River..............................................................................................48 4.2 The Kunene River and Etosha Pan...................................................................53 4.3 The Cuvelai System...........................................................................................63 4.4 The Rest of the Etosha Drainage System.........................................................69 5. The Etosha Pan..........................................................................................................79 5.1 Etosha Pan..........................................................................................................80 5.2 Etosha Pan as an Erosional Landform..............................................................88 5.3 Etosha Pan as a Desiccated Palaeolake......................................................... 110 6. The Development and Evolution of Etosha Pan................................................ 113 6.1 The Timing of the Upper Kunene River’s Deflection to the Atlantic Ocean............................................................................................................... 114 6.2 Etosha Pan as an Erosional Landform........................................................... 115 6.3 Palaeoclimate of the Study Area Since the Late Quaternary....................... 128 6.4 Conclusions .................................................................................................... 134 References......................................................................................................................... 137 Appendix........................................................................................................................... 151 ii List of Figures Figure 2.1: Illustrative multi-temporal false color composite of Landsat images covering the western part of Etosha Pan ....................................................................................7 Figure 2.2: Error in SRTM Elevation data in part of the Cuvelai System..................................8 Figure 2.3: Propagation of the error into a longitudinal profile.................................................8 Figure 2.4: Sample from the "field-guide" book generated from satellite images for fieldwork purposes................................................................................................10 Figure 2.5: Major study sites in and around Etosha Pan ...........................................................10 Figure 2.6: Major study sites in and around Oshana Olushandja / Etaka...................................11 Figure 3.1: Location of the study area......................................................................................14 Figure 3.2: Geological cross-section across the Owambo Basin from Ruacana to Tsumeb .......17 Figure 3.3: Approximate location of the Great Escarpment of Southern Africa and thickness distribution of the Kalahari Group sediments..........................................20 Figure 3.4: Cross-section of the Kalahari Group Sediments in the Owambo Basin along the 16°41' longitude...............................................................................................22 Figure 3.5: Schematic section through the Kalahari Sequence of the Owambo Basin ...............23 Figure 3.6: Digital Elevation Model of the Owambo Basin surface..........................................25 Figure 3.7: Longitudinal profile of the Cubango/Kavango River and its main tributary, the Cuito ...............................................................................................................28 Figure 3.8: Digital Elevation Model (90 m ground resolution) of the Okavango Graben and Makgadikgadi Basin. ......................................................................................30 Figure 3.9: Satellite Imagery (Landsat TM) covering the Makgadikgadi Basin and Okavango Graben..................................................................................................31 Figure 3.10: Wind rose at Okaukuejo from 1982 to1990............................................................40 Figure 3.11: The vegetation structure of the Etosha National Park as derived from the classification of a Landsat TM image ....................................................................43 Figure 3.12: ‘Land use’ of Etosha Pan at different environmental conditions.............................46 Figure 4.1: Longitudinal profile of the Kunene River...............................................................49 Figure 4.2: Longitudinal profile of Oshana Etaka/Olushandja from the Kunene River to Etosha Pan. .......................................................................................................54 Figure 4.3: Spatial setting of oshana Olushandja and Kunene River from a Landsat TM perspective .....................................................................................................55 Figure 4.4: Generalized geomorphological map of Ruacana area .............................................56 Figure 4.5: Selectively stretched DEM of Calueque area. ........................................................57 Figure 4.6: Landsat Imagery covering Olushandja Reservoir and Kunene River environs. .......59 Figure 4.7: Longitudinal profile of Oshana Olushandja/Etaka showing the critical point. .........59 Figure 4.8: Cross-section through major geomorphological units around Ruacana area............60 Figure 4.9: Photo showing the southern flank of the gravel pit, and corresponding profile at K2 .....................................................................................................................61 Figure