Archaeological evidence at a rock shelter on the edge of the Kalahari Desert, South Africa, challenges the idea that the origins of our species were related to coastal environments.
“Our findings from this rock shelter show that oversimplified models for the origins of our species are no longer acceptable. The evidence suggests that many regions of the African continent were involved, and the Kalahari is just one, ”said Dr. Wilkins.
“Archaeological evidence for early Homo sapiens has largely been discovered at coastal sites in South Africa, supporting the idea that our origins were linked to coastal environments. There have been very few datable and well-preserved archaeological sites in the interior of southern Africa that can tell us about the origins of Homo sapiens offshore.
“A rock shelter on Ga-Mohana hill that sits on a vast savannah in the Kalahari is one such site.”
Used today as a place of spiritual activities by the local community, archaeological research at the rock shelter has revealed a long history as a place of spiritual importance.
Researchers excavated 22 white calcite crystals and ostrich eggshell fragments, believed to be used as water containers, from deposits dating back 105,000 years at Ga-Mohana Hill North Rockshelter, when the environment was much older. wet than today. The researchers were delighted to discover that the set of human-collected crystals and ostrich eggshell fragments at Ga-Mohana Hill was significantly older than that reported in indoor environments elsewhere.
“Our analysis indicates that the crystals were not introduced into the deposits through natural processes, but were deliberately collected objects, probably related to spiritual beliefs and rituals,” said Dr. Wilkins.
“The crystals point to the spiritual or cultural use of the refuge 105,000 years ago,” said Dr. Sechaba Maape of the University of the Witwatersrand. “This is remarkable considering that the site is still used for ritual activities today.”
The age of the archaeological layers was limited by Optically Stimulated Luminescence (OSL) dating in the OSL laboratory of the Department of Geology, University of Innsbruck, Austria.
“This technique measures the natural light signals that accumulate over time in sedimentary grains of quartz and feldspar,” said Dr. Michael Meyer, director of the OSL Laboratory. “You can think of each grain as a miniaturized clock, from which we can read this signal of natural light or luminescence, which gives us the age of the archaeological sediment layers.”
The name Kalahari is derived from the word tswana Kgala, which means “great thirst”. And today the weather in Ga-Mohana is semi-arid, with little seasonal rain. However, the ancient evidence of abundant water in the landscape is evident from the abundant tuff formations around the refuge. These were aged using the uranium-thorium dating method to between 110,000 and 100,000 years ago, exactly the same time period that people lived there.
“This is a story of water in what we now know as a dry landscape, and of adaptable people who exploited the landscape not just to survive but to thrive,” says Dr. Robyn Pickering, director of the Human Evolution Research Institute. (HERI) at the University of Cape Town.
Due to the continuing spiritual significance of Ga-Mohana Hill, the researchers are conscious of minimizing its impact on the use of the rock shelter by local communities after each season.
“Leaving no visible traces and working with the local community is critical to the sustainability of the project,” said Dr. Wilkins. “So that Ga-Mohana Hill can continue to provide new insights into the origins and evolution of Homo sapiens in the Kalahari.”
Reference: “Innovative Behaviors of Homo sapiens 105,000 Years Ago in a Moist 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