The Tankwa Karoo is one of the most arid sections of the Karoo (25-100mm rain p/a), a semi-desert which covers central South Africa. The extremely arid summers make large parts of the Karoo unsuitable for farming. The Doring and Tankwa rivers, which rise in the Klein Roggeveld region, drain the Tankwa Karoo. These rivers are non-perennial, experiencing occasional floods during heavy rainstorms. The Tankwa river flows through Stonehenge Private Reserve.
The mean July (winter) minimum temperature is 6°C (lowest measured -1°C), and the mean January (summer) maximum temperature is 38°C (highest measured 50°C). The highest average maximum temperatures occur from November to March with the hottest months being January and February. The highest wind speeds occur from October to March.
In May and June days are usually pleasantly warm, nights can be chilly. Most likely there is no or little rainfall, however, if it rains, it’s often a rainstorm. Dust or sandstorms do occur. The best time to visit Stonehenge Private Reserve and Tankwa Artscape is from March to November.
Animals of the Tankwa Karoo include Aardvark, Jackal, Cape fox, Cape hare, Baboons, Grey duiker, Grey rhebok, Klipspringer, Kudu, Leopard, Meerkat, Porcupine, Honey badger, Dassie, Genet, Springbok, Steenbok, Mongoose and Eagle.
Snakes (cape cobra, puff adder) are rare, due to the scarcity of small mammals to feed on, but do occur, as do scorpions. Some of these animals are extremely shy or nocturnal.
The Tankwa Karoo is within the Succulent Karoo Biome. The Succulent Karoo Biodiversity Hotspot covers some 116,000km2 of desert stretching along the Atlantic coast of Africa, from south-western South Africa into southern Namibia. It is one of the 25 richest and most threatened reservoirs of plant and animal life on earth and the only arid region recognised as a biodiversity hotspot. Compared to other hotspots, the vegetation remains relatively intact. The Lowland Succulent Karoo is described as very sparse shrub land and dwarf shrub land. Dwarf Shrubland (Ganna bush) dominated by leaf succulents is found throughout the Tankwa Karoo.
The Succulent Karoo is vulnerable to several land use pressures, particularly overgrazing on communal lands, ostrich farming in the southeast, mining and the illegal collection of plants and animals for trade. Grasses are uncommon, making most the biome unsuitable for grazing. The low rainfall, in fact, discourages most forms of agriculture. Climate change is also expected to have a serious impact on the region’s biodiversity.
Dwarf shrubland, succulents, Euphorbia, Ruschia, Stipagrostis obtuse
Like many places on earth the Tankwa Karoo has seen significant changes throughout various geological settings over billions of years of Earth history. The sediments which formed the rocks comprising the geology of the Tankwa Karoo were laid down in the deep southwestern portion of a large, intracontinental basin (Karoo basin) that stretched from east of present day Johannesburg to the north of where Ceres is now.
All of this happened around 258 million years ago and available evidence indicates that the water depth for the basin in this vicinity was between 500 – 700m. The slow and methodical ‘filling up’ of the Karoo with sediments over time happened before the initiation of the break up of Gondwanaland, which occurred around 18- -200 million years ago.
Subsequent to the deposition of the Tankwa sediments into the basin, which became rocks over time, a further 7 to 8km of younger sediments were deposited on top of them, themselves forming rocks over time. These latter rocks have been eroded over millions of years to reveal the present day landscape as we can observe it.
Evidence suggest that the Tankwa sediments were sourced from the ‘proto’ Andes mountains, located then ca. 700km from the southwestern portion of the Karoo. The Andes mountains are now thousands of km away!
Only fine grained sedimentary rocks (sandstone and shale rock types) are to be seen in the Tankwa Karoo nowadays. At least five distinct sandstone and shale units gave been identified.
Any oil or gas, which was formed as a matter of course, has been lost over time through seepage and degassing as there were no geological mechanisms to trap it and keep it. Oil and gas geologists have come from all over the world to see ‘first hand’ in the Tankwa what is usually only available to them through remote-sensing instruments and borehole data.
The rocks themselves have not been folded (bent/buckled) by earth pressure as in most other places where deep water, sandstone and shale fans are exploited for hydrocarbons, which makes them ideal to study and learn from.
The Tankwa Karoo is a treasure trove to earth scientists and an amazing open air laboratory – and it’s a beautiful place to feel one’s spirit in the open plains.
A shortened version from the original article by Sven Coles: https://www.afrikaburn.com/binnekringblog/tankwa-geology
The true meaning of the word “Tankwa” is said to be “place of no water” in /Xam, one of the languages of the San (bushmen).
Humans have lived in the Tankwa for at least 10 000 years - first the hunter/gatherer San (Bushmen) and then the Khoi pastoralists, who moved their livestock with the migration of the wild animals. In the 1700s, the Trekboer farmers started using the Tankwa to graze their dropper and merino sheep while moving from the summer heat of the Cederberg to the cooler temperatures on the Karoo escarpment. In the 1800s early European farmers arrived to farm small stock and plant wheat and watermelons, but the arid climate and poor soils meant that farming was not sustainable.
The earliest hunter-gatherers in southern Africa were the San or Bushmen people. The San populated South Africa long before the arrival of the Bantu-speaking nations, and thousands of years before the arrival of Europeans.
The San believed that no individual owned the land and that everybody had the right to use it. Like many societies who depend on the land for survival, they regard it as sacred and respect it as a gift of God.
The San had no formal authority figure or chief, but governed themselves by group consensus. Disputes were resolved through lengthy discussions where all involved had a chance to make their thoughts heard until some agreement was reached. Certain individuals may have assumed leadership in specific spheres in which they excelled, such as hunting or healing rituals, but they could not achieve positions of general influence or power. San were largely egalitarian, sharing such things as meat and tobacco. Kinship bonds provided the basic framework for political models. Membership in a group was determined by residency.
The most important part of the San’s lives was fire. The men were responsible for making fire and used two fire sticks that they carried with them at all times. Fire provided safety, warmth, light and a way to cook food.
San languages with their implosive ‘clicks’, belonged to a totally independent language family. /Xam speakers originally occupied a large part of western and northern South Africa, but by 1850, only a few hundred /Xam speakers survived in remote parts of the Tankwa Karoo and the Northern Cape. Today, the language /Xam no longer exists, but is documented in the LloydBleekCollection at the UCT archives, taken down word-for-word from some of the last /Xam speakers in the 1860s and 1870s by Lucy Lloyd and Wilhelm Bleek. These pages record not just the /Xam language, but also their myths, beliefs and rituals. http://lloydbleekcollection.cs.uct.ac.za/
About 2 000 years ago life for the San began to change significantly in the Western part of Southern Africa. Pastoralists, also known as the Khoi, arrived, bringing with them their cattle and a different way of life. For the San hunter-gatherers many aspects of the Khoi way of life were strange and difficult to understand.
The spread of the Khoi pastoralists into the Cape resulted in a conflict of interests with the San hunter-gatherers of the area. A major source of conflict was competition for game. But while the Khoi started competing with the San for game, their sheep and cattle were creating a further problem by denuding the pastures on which the game was dependent. As the San watched the vast herds of game disappear, they felt justified in killing or stealing the animals that had taken the place of the game as the concept of ownership was foreign to them.
The Trekboere were nomadic pastoralists of European settler and of Khoi descent living on the frontiers of the Dutch Cape Colony. The Trekboere began migrating into the interior Great Karoo and Tankwa Karoo with their hardy local stock of cattle during the late 17th century and throughout the 18th century to escape the autocratic rule of the Dutch East India Company. They were living in their wagons and rarely remained in one location for an extended period of time and traded both with white settlers and indigenous people. They were, like the Khoi, in constant conflict with the San.
The result seems to have been a classic pattern of cultural displacement – aggressive pastoralists (Bantus, Khoi, Trekboere, white settlers) encounter peaceful hunter–gatherers (the San, who like many hunter–gatherer societies, had no warrior tradition at all), and clear them from the land as they would the game, killing the men, taking the women as concubines and gradually assimilating the indigenous culture into their own. Many historians describe the brutal killing of the San people (which was sanctioned by British colonial rule) by Bantus, Khoi, Trekboere and white settlers in the 18th and 19th century as a genocide.