Based on a visit in May 2017. Photos by the author except where otherwise indicated.
To some the South African Karoo is an area to be passed through as quickly as possible while driving between the Cape and the population centres in Gauteng and the rest of the northern regions, or to be flown over even more quickly. For others though it has a magic of its own with views which stretch for ever over plains broken by small flat topped hills and longer ridges. Being of the latter variety we chose to break a trip to the Tankwa Karoo (also known as Tanqua) on the farm Osfontein south of Carnarvon, just off the Loxton road.
This farm lies in the Great Karoo, as opposed to the much smaller Little Karoo south of the Swartberg mountains, and in the higher lying part of the Upper Karoo. Various definitions of what constitutes the Karoo exist but to me a defining feature is the predominance of small bushes growing, of necessity, at least half a metre apart and separated by largely bare ground. The absence of grass is thus is requirement for this and I typically get that Karoo feeling driving out of Colesberg when the NI road turns west driving to Cape Town. However good rains can produce long grass here, even when the rains are not that heavy, giving rise to what my Colesberg acquaintance calls a green drought, as prevailed on our recent trip.
The flat plains of the Karoo reflect the relatively undisturbed sedimentary rocks in contrast to the highly folded Cape mountains to the south. Much of the surface is made up of the remaining part of the 5.6 km thick Beaufort Group. These sediments were then covered by a thick layer of the igneous rock, dolerite, which has largely eroded away except in the Drakensberg to the east. The igneous rock penetrated the sedimentary rocks both vertically to the surface through dykes and horizontally through the sedimentary layers as sills. When the sills are exposed through erosion they protect, for a time, the underlying sedimentary rocks to leave the flat topped hills which are so characteristic of the Karoo (similar to what are termed inselbergs in other parts of the world). In contrast the dykes are evidenced by small sharp ridges typically abounding in rounded boulders. Carboniferous deposits were laid down from time to time during the sedimentation process, hence the interest in fracking. An interesting view on this, from a not necessarily impartial source, comes from Rosemary Falcon of the University of Witwatersrand Clean Coal Technology unit. She maintains that the intrusive dolerite “would have devolatilised much of the oil and gas” in the vicinity of the dykes and sills such that though there may be pockets of gas, “how commercially economic they are for setting up major energy production is yet to be seen.”
Another defining feature of the Karoo is the climate with extremes of heat and cold and generally low rainfall which varies roughly from 50 to 250mm pa. This with summer heat frequently exceeding 40°C produces the semi desert nature of the flora with the Tankwa area being close to full desert. The animals which typify the area by virtue of their drought resistance are springbok and gemsbok though the variety of less noticeable fauna constantly surprises. Despite images of the area presenting a hot dry picture, temperatures can drop to -10°C.
Osfontein farm lies at around 1450 metres above sea level (GPS S31.23500 E22.27201). One can imagine the first European settlers chancing on this place and finding water for their oxen (as the name implies) and for themselves. Nevertheless it is a harsh environment for people and animals and maybe the first to find it still moved on.
Despite this, some of the dwellings on the property date well back into the nineteenth century. Of particular interest is the corbelled house. Stegman and Natasha Lubbe, the current owners tell me that this was constructed nearly 200 years ago by early European settlers due to the lack of timber for a normal roof truss arrangements. The construction is not unlike a typical arch, with keystone, uprated to a three dimensional basis. The photo shows the original two houses to which Stegman has added two more built by himself.
The colour of the sky gives a good idea of the atmospheric clarity given the height and remoteness. Some visitors come for the stargazing. The farm lies between the Southern Africa Large Telescope near Sutherland, noted for the absence of interference on visible wavelengths, and the Square Kilometre Array (SKA) core site north of Carnarvon where freedom from from signals in the 50 MHz to 14 GHz (and later 30GHz) frequency range is required. The SKA incorporates numerous southern hemisphere sites and Wikipedia notes that ”it should be able to survey the sky more than ten thousand times faster than ever before.” This has been a rare achievement for South Africa and has required excellent communications capacity. SKA download levels will be greater than 2013’s internet traffic.
The interior of the corbelled house presents a fascinating sight by virtue of the circular construction (looking directly upwards):
We stayed in the kliphuis, or stone cottage, an old building gutted and then meticulously restored by the Lubbes complete with additional dry stone walling and hand made furniture and fittings combining to present a most pleasant old world ambiance. Just one feature that took some getting used to was the 1.5 metre doorway! An almost permanent resident at the kliphuis was one of the sheepdogs, always looking for attention or otherwise streaking across the veld at amazing speed while we were out walking.
The accommodation on the farm is completed by a tree house comprising a tent pitched on a platform with extensive views over the Karoo. Stegman’s photo inside the very well appointed tent gives an idea of the tree house which naturally has extensive views over the surrounding area.
The farm covers 20,000 hectares of typical Karoo sparse bush scenery but with a dolerite dyke forming a protective ridge behind the farmhouse. The dolerite (which I believe is known as diabase in North America) is a black crystalline rock not unlike the darker granites or basalt but on weathering becomes a fairly light brown on oxidation of the magnetite. It also tends to weather along joints and cracks into large blocks which themselves weather, in these warmer areas of the world, into rounded boulders as the corners and edges weather faster than the faces (spheroidal or onion skin weathering). This sometimes leaves mounds of rocks piled atop each other as though left by some ancient civilisation. The ridges are thus a particularly attractive variation on the surrounding plains. [Walking in the area is covered as a footnote.] The following picture was taken from the top of the small hill behind the farm.
Looking at this farm you can’t but think about the government’s proposals to limit landholdings, which I recall was at one time proposed to be 500 acres. The current Regulation of Agricultural Land Holdings Bill under consideration would give the Minister of Rural Development and Land Reform the power to determine the maximum land holding size for every ‘district’, with a district being a municipal district, which at least would provide some degree of homogeneity within a district but even then there can be great differences between the size of farms needed in valley bottoms and mountain areas. Osfontein at 2,000 hectares (almost 5,000 acres) can only support about 300 sheep, so in no way represents a massive enterprise that should be subject to restriction, despite the area covered. The sparse vegetation has to sustain the sheep through good times and bad with the retailer demanding that organically produced food must originate from farms with solely natural grazing – no bought in feedstuffs – so careful stock management is required to prevent overgrazing. It can easily happen that after walking for a while you may have seen springbok but wonder where the sheep are. This is because the farm is divided into camps and the sheep moved from camp to camp for an optimal grazing routine, and the camps are not small.
The typical absence of clouds makes renewable energy an obvious choice here and the Lubbes are in the vanguard of this in their area with 17 photovoltaic panels producing 4kw and a wind turbine 1kw. These feed two inverters to make 9kw available during the day and 5 kw during the night from 12 200AH 48v batteries. This has greatly reduced their reliance on the grid.
Walking footnote: The land is generally fairly flat and crisscrossed by numerous jeep tracks. Walking from the farmhouse can bring you to fences but these frequently mark the boundaries of camps rather than of the farm itself. The dolerite dykes, although only producing small hills, are quite steep sided, and to walk along the ridges produced by the dykes requires much maneuvering around and over rocks such that the effort expended seems out of proportion to the distance and height achieved. The following picture, although not the best quality, nevertheless shows the rocky and somewhat serrated nature of the ridge .