Namibia is a vast country. The coast line to the Atlantic Ocean (2253 miles long) is its west border. The tropic of Capricorn is about half-way north and south across the country so that summer and winter months are almost opposite those in the UK. The surface area of the country is 824,268 square kilometres. It is bordered by Angola and Zambia in the north (close to where I am in Katima Mulilo), by South Africa in the south and in the east by Botswana (also close to where I am in Katima Mulilo).
There are two huge ancient deserts in Namibia, the Namib (from which the country derived its name) and the Kalahari. The Namib Desert is a long narrow strip of moist coastal desert between 50-140 kilometres in width and 1350 kilometres in length from the north of the country to the south. The Kunene River borders the north of the Namib and the Orange River borders the southern end. This desert is thought to be the oldest on earth along with the Atacama Desert in South America.
The Kalahari Desert is in the east of Namibia, beyond the central plateau highlands (between 1000 – 2000 metres in height). This desert is has typical long, vegetated dunes of deep red sand.
There are granite landscapes in the Damaraland and Brandberg where isolated mountains of hard jagged rock rise up from the surrounding areas. Mineral deposits including diamonds have been found in the rocks in a coastal region north from the Orange River.
Many other rocks of Namibia are sedimentary, formed 600 million years ago at the bottom of huge primeval seas. Since their formation they have been pressurised, transformed and eroded to make the desert landscape. Over millions of years the Orange River has eroded and carried away vast amounts of sand from its origin or source, in the highlands of Lesotho and all along its journey through Namibia to the Atlantic Ocean.
A very strong cold current flows onto the coast, called the Benguela Current. This current works to rebuild the landscape that the Orange River has eroded and transports the sand northwards from the river’s mouth and deposits it on the shore again to create huge coastal dunes. The wind then lifts the sand and moves it again northwest until it is deposited inland again. This process is known as the ‘marching of the dunes’ and it continues at an average rate of 20 metres each year.
The dunes themselves form a variety of shapes but all have a more gentle slope on the exposed side (windward) and a much steeper sheltered side (leeward). Some of the dunes can be 300 metres high (1000 feet) making them the highest of anywhere in the world.
Try to locate the area described on Google Earth and see if you can track the shape of the dunes. Along the coast are crescent shaped dunes which lie perpendicular (at right angles) to the strong southerly winds (ref: Google Earth: Fly to: Namibia Skeleton Coast Park). Further to the east there is a belt of transverse dunes (north and south trending). These lie parallel to the southerly summer winds but are also affected by the strong easterly winds which blow in the winter months. Star dunes are to be found to the east and south of the transverse dunes. These have three or more ‘arms’ extending from their peak or high point. Star dunes are formed by multi-directional winds that move the sand in many different directions. The dunes here ‘rest’ on a horizontal solid sandstone terrace (ref: Googlearth: Fly to: Namibia Sossusvlei).
Next weekend, driving to Swakopmund from Omaruru on the C33 and B2 roads we will cross the southern edge of the Namib dunes / desert.
