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
Archaeological evidence in a rock shelter on the edge of the Kalahari Desert, South Africa, disputes the idea that the origin of our species is linked to coastal environments.
‘Our findings from this rock shelter show that too simplistic models for the origin of our species are no longer acceptable. Evidence suggests that many regions across the African continent were involved, and that the Kalahari was just one, ‘said Dr. Wilkins said.
“Archaeological evidence for early Homo sapiens has largely been discovered in coastal areas in South Africa, supporting the idea that our origins are linked to coastal environments. 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 shelter on the Ga-Mohana hill that stands above a vast savannah in the Kalahari is such a place. ‘
Archaeological excavations at Ga-Mohana Hill North Rockshelter where early evidence for complex behavior of Homo sapiens was found. Credit: Jayne Wilkins
Some of the local communities are used today as a place of spiritual activity, and archaeological research in the rock shelter has revealed a long history as a place of spiritual significance.
The researchers excavated 22 white calcite crystals and fragments of ostrich eggshell, presumably used as water containers, from deposits dating to 105,000 years ago at Ga-Mohana Hill North Rockshelter when the area was much wetter than today. The researchers were delighted to discover that the composition of crystals collected by humans and fragments of the ostrich eggshell at Ga-Mohana Hill was significantly older than reported in domestic environments elsewhere.
“Our analysis indicates that the crystals were not introduced into the deposits via natural processes, but were deliberately collected objects that were probably linked to spiritual beliefs and rituals,” said Dr. Wilkins said.
“The crystals indicate 105,000 years ago spiritual or cultural use of the shelter,” said Dr. Sechaba Maape of the University of the Witwatersrand said. “This is remarkable, as the site is still used today to perform ritual activities.”
The age of the archaeological layers was limited by means of Optically Stimulated Luminescence (OSL) dating in the OSL laboratory at the Department of Geology at Innsbruck University, Austria.
“This technique measures natural light signals that accumulate in sedimentary quartz and feldspar over time,” said Dr. Michael Meyer, head of the OSL lab, said. “You can think of every grain as a miniature clock, from which we can read aloud this natural light or brightness signal, which gives us the age of the archaeological sediment layers.”
Crystals were collected 105,000 years ago by early Homo sapiens in the southern Kalahari. Credit: Jayne Wilkins
The name Kalahari is derived from the Tswana word Kgala, meaning ‘great thirst’. And today the climate at Ga-Mohana is semi-arid, with little, much seasonal rainfall. Ancient evidence of abundant water in the landscape, however, is evident from the abundant tufa formations around the shelter. They were aged between 110,000 and 100,000 years ago using the uranium-thorium dating method – exactly the same period as the people who lived there.
“It’s a story of water in what we now know as a dry landscape, and of adaptable people who use the landscape not only to survive, but also to flourish,” says Dr. Robyn Pickering, director of the Human Evolution Research Institute (HERI) at the University of Cape Town.
Because of the continuing spiritual significance of Ga-Mohana Hill, researchers are aware of limiting their impact on local communities’ use of the rock shelter after each season.
“Leaving no visible traces and working with the local community is crucial to the sustainability of the project,” said Dr. Wilkins said. “So that the Ga-Mohana Hill can continue to provide new insights into the origin and evolution of Homo sapiens in the Kalahari.”
Reference: “Innovative Homo sapiens Behavior 105,000 Years Ago in a Weter Kalahari” by Jayne Wilkins, Benjamin J. Schoville, Robyn Pickering, Luke Gliganic, Benjamin Collins, Kyle S. Brown, Jessica von der Meden, Wendy Khumalo, Michael C. Meyer, Sechaba Maape, Alexander F. Blackwood and Amy Hatton, March 31, 2021, Nature.
DOI: 10.1038 / s41586-021-03419-0