Today Ga-Mohana Hill sits in the middle of a fairly flat and dry landscape, offering a view of the Kalahari dunes. The nearest towns are nearly 4 km away, but new archaeological research suggests that the semi-arid desert has been a site of human congregation – and possibly even spiritual significance – for tens of thousands of years.

In a study Posted in Nature, researchers have found calcite crystals and ostrich eggshell fragments that show signs that humans have collected them. Not only is it difficult to find deposits in rock layers like these, but it is even more unusual to find deposits this old – these finds are estimated to be around 105,000 years old.

The Kalahari, which covers much of southern Africa, receives an irregular amount of rain each year, with severe thunderstorms in summer and extremely dry winters. But the rains in the Kalahari instantly flow through its sand dunes, creating an effective drought. Despite this, archaeologists question the idea that the coastal environments of southern Africa were the only home of early humans. “This tells us that people were able to explore completely different environments, that they were not tied to the coastline,” said Michael C. Meyer of the Institute of Geology at the University of Innsbruck, in Austria, and also one of the study’s authors. This new evidence suggests that the Kalahari could also have supported people.

While there is no definitive evidence as to exactly why these crystals and eggshells were found collected from a rock shelter, archaeologists and geologists involved in the study have strong hypotheses. The artifacts show no signs of wear, nor any modification to suggest that they were used as tools. Researchers also found an abundance of preferable raw materials for stone tools all over the hillside, which early humans would certainly have used in place of seashells and crystals.

Robyn Pickering, a geologist and director of the University of Cape Town’s Institute for Human Evolutionary Research, who authored the study, notes that other explanations of how these crystals could have gotten here without human intervention does not seem to match the geology at Ga-Mohana. One explanation would be that calcite formed when water passed through the area. But the crystals formed this way would be aligned in the same direction, while these are not. Crystals can also naturally accumulate in the roof and walls of the shelter, and could have just fallen. But there was no immediate source of calcite found inside or near the cave to suggest that this happened.

“The closest source we have found for this type of crystal is over two kilometers away. [1.25 miles] away, ”says Ben Schoville, a senior lecturer at the University of Queensland who helped lead the search for crystals. “So we know people were bringing them. And when we searched them, we actually found most of them in a fairly small area the size of a basketball.”

Leaving the two explanations aside, it seems that the relatively high concentration of crystals in this 105,000-year-old layer is no accident. These crystals were deliberately collected and brought to the site. This type of behavior is indicative of what archaeologists call complex human behavior. As complex human behavior is essentially “people doing things for non-utilitarian purposes,” says Pickering. “Collecting beautiful crystals, which have no functional purpose? We identify this as a trace of complex behavior. Evidence of this type of behavior has often pointed to the shores of South Africa, but these new findings challenge that narrative.

While the scientific literature on early human origins has always pointed firmly to Africa, much of the research has suggested that it was primarily the coastal areas that were home to these peoples. Corn more recent studies identified the interior of Botswana and southern Africa as the site of some of the earliest Homo sapiens. The discovery of these 22 white calcite crystals and eggshell fragmentations further supports these theories. The ostrich eggshell containers in particular, which could have been designed to be water containers, and the rock shelter where they were found suggest a time when the Kalahari Desert was much wetter than ‘today.

The rock shelter looks like a cave, but it is much shallower and has been created by erosion over time in the hill. It is covered with another type of rock formation called tuff, a type of limestone made up of calcium carbonate. Pickering notes that the tuff formations must have been created by puddles of standing water above the rock shelter which then sank down the sides of the shelter. “The way they form is [through] the water cascades down the sides of the rock shelter. And as it happens, this turbulent flow causes calcium carbonate to precipitate out of solution. “

“So back then, when they were active, there were waterfalls pouring down the side of the rocky shell,” she says. “It’s a really different picture of a really arid region today.”

After dating portions of this tuff formation, Pickering and his team discovered that one of these rock formation episodes occurred exactly between 110,000 and 100,000 years ago, around the same time humans are believed to have occupied the rock shelter. It means that sooner Homo sapiens the presence coincided with a period when this part of the Kalahari had waterfalls. This evidence, along with the fact that the eggshell fragments appear to have been burned and show no sign of collection by carnivores or scavengers, leads researchers to infer that they could have been used to collect and transport the water.

Although the spiritual practices of 105,000 years ago have long been lost, Ga-Mohana Hill and its surroundings are now home to modern communities with their own connections to the landscape. The region is still considered today as a spiritual place. For this reason, the team took care not to leave any traces of their excavations to ensure that the terrain remains as it was before their arrival. After all, as we roam the earth in search of science, respecting living communities is just as important as discovering ancient communities.