New research on a rock outcrop on the edge of the Kalahari Desert in South Africa disputes the assumption that modern human origins and complex behaviors were limited to coastal environments. A collection of unusual artifacts that are more than 100,000 years old indicates that the interior Homo sapiens was just as innovative as their cousins on the coast.
There is a general belief that the origins of modern humans and modern human cognition may lie in southern Africa. Since many of the archeological sites associated with early human activities are located on the coast, experts have adopted it Homo sapiens their technological and symbolic behavior also developed in that region. But a new study published in the journal Nature paints a very different picture.
One of the stone tools excavated from the Ga-Mohana Hill North Rockshelter. (Credit: Jayne Wilkins)
The oldest evidence for modern humans in the Kalahari Desert
An international team of scientists has explored the Ga-Mohana Hill North Rockshelter, a terrain overlooking the savannah of the Kalahari Desert and more than 600 km (370 miles) inland. Chief Writer, dr. Jayne Wilkins, of Griffith University’s Australian Human Evolution Research Center, explained the importance of the discovery in a press release from the University of Innsbruck:
“Our findings of this rock help show that too simplified models for the origin of our species are no longer acceptable. Evidence suggests that many regions across the African continent were involved, and the Kalahari was only one […] There were very few preserved, dateable archaeological sites in the interior of southern Africa that could tell us about the origin of Homo sapiens off the coast. A rock hero on the Ga-Mohana hill that stands above a vast savannah in the Kalahari is such a terrain. ”
According to the press release, the scientists’ work also provides’ the oldest evidence for modern humans in the Kalahari Desert in Africa ‘.
Archaeological excavations at Ga-Mohana Hill North Rockshelter, where early evidence for complex Homo sapiens behavior has been restored. (Credit: Jayne Wilkins)
View “Miniature Clocks”
An analysis of the site and the artifacts found in the rock shelter provide evidence that the behavioral patterns of Homo sapiens on the site was parallel to what happened 100,000 years ago on the coast. The primary evidence comes from a collection of calcite crystals and fragments of ostrich eggshell, which, according to the researchers, may have been used as a container for water storage.
Using Optically Stimulated Luminescence (OSL), the team determined the age of the various archaeological layers in which the artifacts were found and dated the objects to 105,000 years old. Michael Meyer, the head of the OSL laboratory at the Institute of Geology at the University of Innsbruck and the geologist who led the OSL analysis, explained the technique:
‘This method utilizes natural light signals that accumulate in sedimentary quartz and feldspar grains over time. You have to think of each grain as a miniature clock. Under controlled laboratory conditions, we can read aloud this natural light or so-called luminescent signal, which in turn informs us about the age of the archaeological sediment layers. The lighter the older the sediment. ”
The researchers also noted that the climate of the Kalahari Desert was much wetter – as evidenced by the tufa (a type of limestone) formations found around the rock shelter. Uranium-thorium dating of these features provides an age of between 110,000 and 100,000 years – the same time that the ancient people inhabited the place.
A collection of Kalahari crystals – symbols of a very ancient sacred palace?
Initially, the collection of 22 calcite crystals presented something of a mystery because the researchers, unlike the pieces of the ostrich shell, could not see any obvious utility for it. Then they decided it was a clue. Dr. Wilkins said: “Our analysis shows that the crystals were not brought into the deposits by natural processes, but were deliberately collected objects that were probably linked to spiritual beliefs and rituals.”
Crystals are collected early Homo sapiens 105,000 years ago in the southern Kalahari. (Credit: Jayne Wilkins)
Study co-author, dr. Sechaba Maape, of the University of the Witwatersrand, agrees and said: “This is remarkable, as the site is still used today to practice ritual activities.” The archaeological team is aware of the fact that the Ga-Mohana hill still has spiritual significance for local communities, and they say they are trying to limit their impact on the local use of the rock shelter. “Leaving no visible traces and working with the local community is critical to the sustainability of the project,” said Dr. Wilkins noted that this is also important. “So that Ga-Mohana Hill can continue to provide new insights into the origin and evolution of Homo sapiens in the Kalahari.”
The archeological site at a rock shelter in the Kalahari Desert in South Africa. More than 100,000 years ago, people used the so-called Ga-Mohana Hill North Rockshelter for spiritual activities. (Credit: Jayne Wilkins)
The article, entitled “Innovative Homo sapiens behavior 105,000 years ago in a wetter Kalahari, ”is published in the magazine Nature.
Top image: Calcite crystal is excavated from 105,000 year old deposits at Ga-Mohana Hill North Rockshelter in the Kalahari Desert in South Africa. Source: Jayne Wilkins
By Alicia McDermott