One of Namibia’s most well-known features are the iconic ocher dunes of the Namib Sand Sea. Fascination with this sea of sand began in 1960 when the first satellite images of the earth were presented to the world. One of the most curious features these early images revealed was the abrupt end of the sand sea on the southern edge of the Kuiseb River.
A few hiccups of sand dunes occur on the southern bank of more northerly rivers, but this abrupt end of the major sand sea is visibly dramatic.
The Kuiseb River runs just often enough to stop the sand from crossing the barrier
Image left shows the dramatic end to the sand sea just south of the Namib Desert Safari route
Declared a UNESCO World Heritage Site in 2007 along with the rock engravings of Twyfelfontein, the sinuous dunes of the Namib are compelling subjects for photographers. The supply of sand originates from the Orange River and is carried northward by the upwelling Benquela Current and deposited back onshore further north where powerful winds carry the sand inland.
Dune Types Found in the Namib
On the coast where sand supply is low, crescent-shaped Barchan dunes form. Able of move rapidly (up to 30 metres a year) these dunes are capable of consuming roads, railway lines and even buildings – very evident on the road to Luderitz.
Inland dunes derive their deep ochre colour from the presence of haematite (iron oxide) which forms on more stable dunes. The paler costal dunes on the coast (image above), where movement of sand is greater, don’t allow the oxidation process to develop.
Further inland where more sand is available, long linear dunes of the greater sand sea produce giant dune ridges like mountain ranges.
Formed by strong prevailing contrary winds from east and south west, these dunes move slowly northward until they come up against a formidable obstacle of the Kuiseb River. (See blog on Ephemeral Rivers)
The distinctive ochre colour of these dunes is apparent compared to the paler coastal dunes above
Very little grows permanently on sand dunes, except for the true giants of the Namib Sand Sea, the star dunes around Sossusvlei. (Image left) Here weaker multi-directional winds are unable to move much sand. Over 300 metres high, these giants support an astonishing amount of life for so arid an area.
Adaptations for survival in this sea of sand abound – from behavioural to physiological adaptations – the fascinating creatures of the Namib never cease to astound in their ability to survive in this harsh environment. Sand swimming avoids exposure to predators, heat and aridity. The flattened bodies of Darkling beetles and shovel snouts of lizards (image right), tubular nostrils and protective eyelids - all ease life below the sand surface.
There is something indescribable about these overwhelmingly vast places that moves us in ways we cannot explain. The great psychologist C.G Jung observed, on his first visit to Africa, that he had the remarkable certainty that he had seen it all before – the vast plains and endless vistas. The deeper into Africa he went, the closer his identification with Africa become… and gave him his final confirmation of the collective unconscious in man. Is it this which captivates, intrigues and enchants – this forgotten primitive awakening…
“Travel for travel sake” Jung said, “is one thing; quite another is the far more difficult journey some of us are called upon to undertake into the unknown universe of ourselves.”
Africa provokes what has been forgotten in us….