The route begins at the Bundi River Rafters Camp and follows through to Aussenkehr. Many landmarks down the Orange River have been given informal names by the river guides. The geological background to these landmarks follows.
The cliffs of yellow-weathering strata are of sedimentary origin and belong to the Dwyka Tillite Formation of the Karoo Super group. They are approximately 300 million years old. They continue to outcrop past the first weir and change to black near river level as the river makes a broad left bend of rapid water. Look out for large dropstones within the black tillite exposures.
Not to be confused with the Echo Cliffs, this comes later. Soon after leaving the camp a series of sheer grey limestone cliffs rise over the left bank of the river. This limestone’s belong to the Nama Group and were deposited in shallow seas from about 540 million years ago. Today the modern setting would be similar to the tropical coral reefs of the Caribbean, but back then the only life forms would have been primitive algae that precipitated the carbonate as planar to wavy mats.
Look carefully at the thick limestone beds and you will notice that they are built of numerous thin laminae, each of which would represent annual seasonal accumulation, much like the growth rings of trees. Counting up these thin laminae would allow you to establish how many years it took to deposit the entire cliff thickness; it probably took several thousands of years. From a distance the thick limestone layers show a broad wavy pattern described as open folds. Squeezing of the strata as if in a vice has caused the originally flat-laying beds to buckle, much in the same way as folding a magazine. Sound is bounced back from these cliffs in a dramatic fashion, the time for the echo depending on the distance. Try shouting or smacking the river with your paddles.
The Nama limestones rise out of the river into a stupendous sheer wall that dwarfs even the Echo Krantzes. About halfway along Echo Cliffs you can see a vertical crack in the rock layers, where displacement has occurred. This vertical crack is called a fault, probably produced during an ancient earthquake that heralded the breakup of Gondwanaland about 300 million years ago.
Many of these faults contributed to the splitting of the continent and the ultimate drifting away of South America from Africa. All the major rift faults along the coast are now obscured by the ocean, so we have to look elsewhere for their smaller associated breaks, which you can see extended quite a distance inland.
Also called “Thumbprint” or “Swiss Roll”. The Snail represents a smoother fold structure, caused by the buckling under pressure that was exerted during the rifting of Gondwanaland. Very soon along the river the Nama beds disappear from the canyon altogether along a major fault boundary, so the folds represented by Snail are part of this contorted zone heralding the margin. The faults in Echo Cliffs and accompanying snail folds have all developed along the edge of a graben within which the Nama Group have been preserved.
Peace of Ashes – Petroglyphs
Just beyond Echo Cliffs and below Snail, the left bank plays host to most likely San rock paintings (Petroglyphs) that are preserved on the smooth flat faces of large Nama limestone blocks that have fallen from the ridges behind the left bank.
An imposing black tower rises abruptly from the left bank and marks the confluence of the Stinkfontein River. This river forced the Orange to the right by the boulder field washing out from its floods. Weathering of the black tower, which is formed from one of the numerous dykes running along the length of the Orange, has produced a pattern of joints and pit readily likened to the face of the famous movie monster. The grassy terraces below KK’s glaring stare is a favourite camping spot, and one can take the opportunity to climb the tower for spectacular views of the Canyon and Richtersveld mountains
Sjambok Fluorspar Mine
The west wall of Sjambok Kloof near its junction with the Orange is made up of Richtersveld granite, cut by several veins of fluorite (or fluorspar), which has been mined on a small scale since the early 20th century. Small dumps of fluorite are still remaining below the cliffs. River travelers are known to gather some for grinding into powder and throwing onto the coals of a fire. Fluorite reacts to the heat by becoming luminescent, glowing a pale blue color and popping vigorously due to the thermal stress. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture or are also usable in the far-ultraviolet range, where conventional glasses are too absorbent for use.
7 Pillars Mine
The name comes from the book of Proverbs comparing the creation of Wisdom’s house being hewn from Seven pillars, with the late Rudi Beneke fashioning a mine from the unforgiving rock. Also, the massive table mountain of quartzite that looms over the mine workings has a series of vertical fissures that give the appearance of several pillars. Diamonds have been recovered from ancient gravel terraces that are perched above the modern channel of the Orange River, attesting to a greater flow in the distant past. Continued down cutting of the river results in portions of these old terraces being preserved high on the canyon wall.
A fanciful comparison to the long pointed hats worn by these much maligned women, the Witches refer to a series of eroded quartzite towers that rise sheer from the Orange River canyon. After Seven Pillars, the Orange turns almost to a right angle to the west again and then curves in a series of arcs through the Rosyntjieberg gorge. Here the hard unyielding quartzite ridges cross the river and build several imposing peaks, the first viewed from a distance over a broad expanse of still water. Witches Hat is composed of tightly contorted beds of grey quartzite.
Some of the quartzite towers that border the Rosyntjieberg gorge contain sedimentary layers that reveal the origin of the hard grey rock. Initially laid down in shallow seas nearly 2000 million years ago as clean white sand, much like that seen on all the west coast beaches today, the sediment was buried and hardened by heat and pressure, then buckled by prolonged Earth movements. Erosion of the overburden revealed these tightly folded layers, which now appears as steep lines, or scratches, in the canyon walls. Inter-bedded with the pale quartzite are thin bands of black rock full of the iron oxide mineral magnetite. The sharp contrast of black and white beds in close proximity probably highlights the vertical structures.
Some of the quartzite towers that border the Rosyntjieberg gorge contain sedimentary layers that reveal the origin of the hard grey rock. Initially laid down in shallow seas nearly 2000 million years ago as clean white sand, much like that seen on all the west coast beaches today. The sediment was buried and hardened by heat and pressure, then buckled by prolonged earth movements. Erosion of the overburden revealed these tightly folded layers, which now appears as steep lines or scratches in the canyon walls. Inter-bedded with the pale quartzite are thin bands of black rock full of the iron oxide mineral magnetite. The sharp contrast of black and white beds in close proximity probably highlights the vertical structures.
With broad plains stretching away on both sides, the Orange River becomes very sedate and resembles a huge lake with practically no current flow whatsoever. Paddling this section is a major mission, especially in a strong headwind (divorce straights), as inactivity will cause you to retrace your route back upstream. Both banks are thickly forested, the left masking the diamond workings, and the right bordering the vast irrigated plains of table grape vines and many other fruit and vegetable crops. With the feeble flow of the river offering practically no sound, only the steady whine of the pumps that siphon the water up to reservoirs break the silence.