Sky, sand and sea merge in the Bay of Sandwich, once an ancient harbour that sheltered sailing ships riding at anchor to load white gold in the form of bird guano and blubber from butchered whales. Those primitive scenes have given way to modern all-wheel drive vehicles, powered by turbo-charged diesel engines, carrying a cargo of holidaymakers. Replete with Global Positioning Systems, two-way radios, cell phones, and the latest in fishing gear, they descend on remote beaches to relax and savour the emptiness.Above them tower the dunes of the oldest desert in the world. Where does all this sand come from? Trace its origins back to the vast hinterlands of South Africa where erosion moves huge amounts of weathered rocks into streams and tributaries that merge to form the mighty Vaal and Orange Rivers. Now called the Gariep, the Orange wends its way through tortuous gorges, emptying its load into the northward-flowing Benguela Current. The basic chemistry of much of this copious discharge is silica oxide or sand, as we know it. Billions of shiny sand crystals pour into the Atlantic Ocean, entering a new world of thundering surf and rasping wind. Curling waves dump this burden back onto beaches where the Sun dries it and the wind carries it to tumble and be reborn as fresh, new pale dunes that soar above the sea. The chemical processes move on relentlessly – tiny iron particles that adhere to the sand begin to oxidize, reddening it, and the ceaseless wind moves the sand ever inland. Eventually, after millions of years, giant dunes rise skywards in the vicinity of Sossusvlei, their crests cascading onto slip-faces, leaving a knife-edge of red sand jutting more than 300 metres into the azure sky. The rusting process is complete.
Moving northwards past Walvis Bay, a narrow spit of land called Pelican Point grows several metres a year, its arrowhead pointing forebodingly towards the land. Eventually, given time, it will encase the present bay to form a shallow lagoon like Sandwich Bay and Conception Bay to the south have done. The evolution of this coast is dynamic and unremitting. Bays appear and disappear. So too do the dune fields. Suddenly, as if cut off by a giant knife the Namib ‘sand sea’ stops at the southern bank of the Kuiseb River, pushing a thin sliver of pale dunes past Walvis Bay to Swakopmund. Why the sudden cessation of sand? The irregular pulses of water that flood the Kuiseb River flush sand from the leading dunes, scouring it and depositing it downstream where the south-westerly wind again plays with the grains, driving them ever northwards. But even the wind has its limits. The powerful ‘wind funnels’ that are responsible for building the 34 000 km2 dune desert between Lüderitz and Walvis Bay decrease their strength towards Swakopmund, leaving the sand stranded. Aeolian sand (the mythical Greek God of the Wind) is totally dependent on its master to proliferate into the giant dunes that make the Namib famous.
Passing Walvis (“Whale”) Bay, two square bunkers of concrete jut grotesquely from their sandy bed in the vicinity of the guano platform, on the approach to Long Beach. Built by the South African armed forces during World War II, their formidable cannons safeguarded the entrance to the harbour against German warships. Now they stand, mute and slowly disintegrating as the grains, whipped up by the persistent winds, scour them like sandpaper.
Rocks replace sand at intervals, their colours and shapes bearing testimony to the heat and pressure by which they were wrought. Jet-black dolerite dykes jut glistening into the sea, their shapes softened by millenniums of pounding waves. Next to them shafts of almost pure white and pink marble mark where liquid intrusions once forced molten magma into faults of the newly-born Earth. They are the remnants of an umbilical link with South America when it and Africa combined to form the super continent of Gondwana some 130 million years ago. Now South America has drifted thousands of kilometres westwards. Rocks of other colours range between these spectrum extremes and together the rocky banks form a kaleidoscope of pools. The rich, oxygenated seawater washes them ceaselessly by day and night with tidal fluxes. They are home to a myriad of marine diversity. Small fish dart among colourful starfish, anemones and mussel banks while sea urchins and snails slowly wend their way, grazing from the ocean floor. Further out, in the wave zone, kelp beds bob gracefully in rhythm with the sea’s urging.
Strange how one’s mind darts here and there while wandering along this paradise of life. I am reminded of a humorous geologist’s formula for describing the range of hardness in minerals found in rocks. On a rating scale of 1 (the softest) to 10 (the hardest), it proclaims that “Tall Girls Can Flirt And Other Queer Things Can Do”. This is a prompt to remember that Talc, Gypsum, Carbon, Fluorite, Andesite, Orthoclase, Quartz, Tourmaline, Carborundum and Diamond are examples of varying solidity in the mineral world.
Between the rocky outcrops sandy beaches stretch, displaying white, brown, purple and black grains. Some of these are magnetic minerals and words like magnetite, ilmenite, titanium and garnet flash through my mind. If teased by drawing a magnet across the surface these minerals will adhere, clinging to the compelling force to assume a dense cluster of fine, hair-like particles on the magnet’s smooth surface. Often the sand’s pattern is broken by the webbed imprint of a ponderous pelican waddling along the shore, or the distinctive paw print of a jackal as it patrols the tidal wash tirelessly in search of morsels thrown up by the waves.
The cry of kelp gulls brings me back to reality. I watch them collect washed up mussels, bearing them aloft and then hovering, to drop the shells within uncanny accuracy onto rocks where they shatter and provide a tasty meal for these persistent scavengers. Prompted by their behaviour I begin collecting fresh brown mussels, wrenching them from their attachment to the rocks. Washed first in seawater and then rinsed in fresh water with flour added to assist the bivalves to flush themselves of grit and other impurities, they will, boiled or grilled over an open fire, provide me with a tangible reminder that all life originated in the oceans.
There can be few experiences as rewarding as walking barefoot along the Namib shore, feeling the fresh sand and icy flush of Antarctic water swirling around your ankles. Kilometres of sand and rocks merge, receding into the distance as you pass. Suddenly, acting on a cue from the wind, a fogbank drifts shoreward enveloping you in a cool blanket of moisture. As it moves inland, lichens unfurl and change from lifeless forms to present an array of shapes and colours. The lifeblood of the Namib Desert has arrived and with it another secret – moisture that ensures it will remain the most diverse desert on Earth. A walk along the Namib coast takes you back in time as far as your thoughts are able to wander; at the same time reminding you of its present vitality and abundance of living things.
