Africa: Wet and Dry!

Notes de l'éditeur

1. These roads however are quite hazardous. Pole dancers on the road signs are the least of your problems!
2. Animals more so – especially at night. They all seem to sleep on the road.
3. Armoured ground crickets smell to high heaven if you run them over and they seem to like to eat their own roadkill.
4. Most of the roads are gravel and there are good gravel roads and bad.
5. Accidents are commonplace.
6. Namibia is an arid country that has a semi- arid desert (100-200mm per annum) on its south eastern edge (Kalahari) and a severe desert (less than 50mm per annum) on its western edge (Namib). A desert is an area which receives less than 250mm of precipitation. This definition is often contested. Why? This map is courtesy of the Digital Atlas of Namibia. Higher resolution download available from www.uni-koeln.de/stb389/e/e1/download/atlas_namibia
7. The Okavango Delta (or Okavango Grassland) in Botswana is a very large inland delta formed where the Okavango River reaches a tectonic trough in the central part of the endorheic basin of the Kalahari. All the water reaching the Delta is ultimately evaporated and transpired, and does not flow into any sea or ocean. Each year approximately 11 cubic kilometres of water spreads over the 6,000-15,000 km² area.
8. Look after your car, mister?
9. Lianshulu Lodge – the waters peak between June and August.
10. The basin only has an altitudinal range of 2 metres. More like a lake than a river.
11. Tsodillo is 48 kms away – or 3 hours on the backie!
12. Not the best of roads then…
13. A Kalahari Ferrari!
14. These hills are of great cultural and spiritual significance to the San peoples of the Kalahari. They believe the hills are a resting place for the spirits of the deceased and that these spirits will cause misfortune and bad luck if anyone hunts or causes death near the hills. The San people believe these hills to be the site of first Creation. Factually, the San people painted more than 4500 rock paintings against the magnificent stone faces of the Tsodilo Hills, making it one of the most historically significant art sites in the world. The San did most of the paintings, although there are a few by Bantu-speakers whose style differs from that of the San. The exact age of the paintings is not known although some are thought to be more than 20,000 years old. The hills contain 500 individual sites representing thousands of years of human habitation.
15. Tsodilo means “sheer”.
16. This is Brad – the croc diver in “Planet Earth” and the Nat Geographic Planet Explorer.
17. The burning season. They burn here mainly to improve the pasture.
18. There is invariably a queue for petrol.
19. Wind, by itself, can remove only dry unconsolidated deposits. This process of lowering the land surface through the removal of clay, silt and sand particles is called deflation. Wind and fluvial (water) erosion, transportation and deposition have resulted in the formation of three main types of desert surface.
20. Geology, relief and water determine the landscapes of Namibia. A fourth major desert landscape type has to be mentioned when studying Namibia. Numerous PANS or dry lake beds are to be found in Namibia. One of these pans, Etosha, is large enough to be seen from space as shown here.
21. There are two kinds of pan surface in Namibia. Etosha is a SALT PAN. It does flood occasionally but the main cycle of water is that of groundwater being drawn upwards through the crust of the pan to be evaporated off on the surface leaving behind a variety of salts.
22. Kori Bustard – can actually fly!
23. So we say goodbye to Etosha and head south towards the coastal desert.
24. The rocky desert (the HAMADA of the Sahara) - a desolate surface of bedrock with patches of rubble and sand. An example of hamada is provided here by the Luderitz peninsula. Chemical weathering by salt appears to be contributing to this landscape. (see the notes on Death Valley - Ventifact Ridge)
25. An example of a stony desert (the REG of the Sahara) - with a surface covered by gravel, pebbles or even boulders.
26. An example of a sandy desert (the ERG of the Sahara).
27. A thin layer of closely packed gravel protects many of the plain surfaces in Namibia. This desert pavement protects the underlying sediment from deflation. It is also sometimes referred to as desert armour or desert mosaic. These lag deposits usually form a thin layer over predominantly finer material. Lag deposits usually form as a result of deflation from poorly sorted deposits such as alluvium.
28. Welwitschia plants - living fossils – up to 2000 years old Found in Namibia and Angola. At threat from collectors.
29. Sossusvlei is a CLAY PAN where the water table is a considerable distance below the surface for most of the year and the main movement of water is downwards leaving behind a clay residue on the pan surface. The infiltration capacity of the clay is low and surface water lasts days or even months, depending on the depth of the inundation.