The glamour of prospecting

by Fred C. Cornell

FORMATION OF THE DUNES AND PANS—“KOBO-KOBO” PAN—RAIN IN THE DESERT—SCORPIONS—AAR PAN—MIRAGE AND “SAND-DEVILS”—KOICHIE KA—THE PIT AND THE PUFF-ADDER.

The long, parallel, wave-like formation of the sand-dunes of the Kalahari has been explained by many scientists as the result of the action of the prevailing wind, but this theory scarcely holds water. For though the majority of the dunes trend between west-north-west and east-south-east, this uniformity is broken in the vicinity of each of the numerous pans, around which the dunes are often formed in concentric rings, whilst the dried-up river-beds are usually flanked for some distance with dunes running parallel to their devious courses. So prominent is this concentric formation near many of the almost circular pans, that it appears probable that volcanic activity may have been the disturbing factor which formed both “pan” and dunes. Certain it is that no “prevailing wind” such as still blows, and still moves sand, would have formed either “waves” or rings as they lie to-day; and though science may be able to refute my theory, it is that the former were formed by successive and severe earth tremors (or earth waves) passing in the same direction whilst the sand was loose and without the binding vegetation much of it bears to-day, whilst the upheaval of volcanic magma similar to that of the Kimberley mine had in many instances formed the latter.

Many ingenious theories have also been advanced as to the origin of these pans, which, although such a feature of the desert, are by no means confined to it. They are generally believed to have also been formed by the action of the prevailing wind (which seems to have quite a lot to answer for!), and doubtless in many places, where the sand is thin, this had been the case. But it can scarcely have been the case in these numerous pans of the “Game Reserve,” where the sand is at its deepest, and where many of the circular or oval pans are surrounded and protected by dunes of well over 100 feet in height, as with a wall. A learned German scientist (Passarge) has suggested that pans have been formed through vast herds of animals drinking and wallowing in the mud at these spots, causing depressions in which rain-water and sub-surface water collected, and I believe this is generally given as an explanation of the salt pans such as I have described.

But for animals to “wallow in mud” presupposes water in these spots, and they must have been free of sand in the first place to allow of water standing there.

I have visited scores of these pans, and I have found them to differ so greatly that it is hard to find a theory that would account for them all. In many the soil is what is known locally as brak alkaline, spongy, powdery, into which the foot sinks deep at every step; in others the surface is a hard, sun-baked mud, red in colour and covered with a shining glaze. Some are salt pans such as I have described, in others I found several feet of blue or greenish “pot clay,” under which was a sort of black volcanic mud; still others were filled with a species of Kimberlite (blue ground) almost identical with that of the Premier Mine; and though the surface was often the usual blue shale that underlies most of the desert sand, in very many cases these depressions—on which the surrounding sand never accumulates—marked an entirely different “country rock” from that of the region generally.

One useful peculiarity about these pans, and one by which we were able eventually to locate them, was that their position was invariably marked by exceptionally high dunes in the immediate vicinity—usually on the south side; those of Aar Pan, the highest in the Reserve, being a good 300 feet above the level of the pan they flank.

But to return to our own particular troubles.

Old Gert, when he had been given a very drastically edited account of our trip, was able to describe minutely how we could take our bearings from the Salt Pan to find a large pan called “Kobo-Kobo,” whence the locating of our first diamond pan would be easy, and a day or two later Du Toit, Telfer, and myself made an attempt to reach it; van Reenen, with the “boys,” meanwhile testing a small pan about a mile to the north, where volcanic action was unmistakable, but where we found only pot-clay and volcanic mud.

As we had a great distance to traverse, we this time took the precaution to load ourselves well with water, each man starting with several spare bottles, which we buried at prominent spots along the route. By midday we were at the Salt Pan, which we skirted, and with a short rest pressed on, and by evening had reached the big pan, “Kobo-Kobo.” It is one of the most perfect pans in the desert, as true a circle as though drawn by a compass, surmounted by extremely high dunes, and with a perfectly level, spongy, alkaline floor. In common with most of the pans, it appears to have at some time contained a large quantity of water, as the margin was covered with a miniature beach of pebbles of jasper, banded ironstone, etc., identical with the deposits found along the Orange River. On one of the dunes near it stood a solitary wit boom, a big tree for these parts, about 10 feet high, and in the branches of which was a Bushman’s sleeping place, composed of a few sticks placed across each other, and on which they take refuge at night, when leopards or wild dogs are around and they do not wish to make a fire. It was a very old nest, however, and the bird had long since flown. Here we rested comfortably, the dry sticks making a good fire. Towards morning a cold, gusty wind got up and the morning broke with a sky completely overcast. It had threatened rain so often that we thought nothing of it, and leaving our food, water, etc., in the tree, we set out towards the highest dunes on the farther side of the pan, from which we hoped to see the smaller one we wanted so badly. Arrived there, however, we found that this time at least the thunder-clouds were not bluffing, for rain was coming across the desert in that direction in a perfect sheet, and whilst we stood discussing plans, the first big drops began to fall amongst us.

We were totally unprepared for it, being dressed in two garments only of the thinnest khaki: it was quite useless for us to attempt to find the pan till it was over, and with one accord we turned back towards the tiny tree—the only bit of “shelter” within a day of us. By the time we were half across the pan the rain was coming down in sheets, punctuated with flashes of lightning, and the spongy surface of the pan was transformed into a quagmire in which we struggled up to our ankles. So soft did the brak become in a few minutes that I had serious misgivings as to whether the whole place would not dissolve into a sort of quicksand and engulf us, and I was extremely glad to be again amongst the dunes.