Israeli scholars find millions of years old human traces in ‘Miracle’ cave

A group of researchers from the Hebrew University of Jerusalem and the University of Toronto have unearthed traces of human activity dating back millions of years in the Wonderwerk Cave in the Kalahari Desert in South Africa. The results were published in the May issue of Quaternary Science Reviews.

The cave, whose name means ‘miracle’ in Afrikaans, offers some of the earliest evidence of the use of fire and the production of tools.

The new study used paleomagnetism and burial dating to scan sedimentary layers 2.5 meters thick containing ashes and animal remains, tools and fires.

Oldowan choppers, scrapers and hand axes are the oldest man-made tools. They usually consisted of roughly worked cutting tools whipped in two directions.

“Wonderwerk is unique among the ancient sites of Oldowan, a type of tool first discovered 2.6 million years ago in East Africa, precisely because it is a cave and not an outdoor event, ”Shaar said.

Attributing traces of open-air fires to human activity is more difficult because the influence of natural fires cannot be definitively excluded.

Paleomagnetism is the study of magnetic rocks and sediments to document the history of the Earth’s magnetic field, which has implications for a wide range of problems, including climate change and navigation systems.

When objects containing magnetic minerals burn at a very high temperature, the minerals are re-magnetized and register the direction and amplitude of the field at that precise moment.

While the direction of the Earth’s magnetic field has pointed to true north in the modern era, it was previously completely neutral or even pointing south.

“We carefully removed hundreds of tiny sediment samples from the cave walls and measured their magnetic signal,” Shaar said. “Our lab analysis showed that some of the samples were magnetized south rather than north, which is the direction of the current magnetic field. Since the exact timing of these magnetic “reversals” is widely recognized, this has given us clues to the antiquity of the entire sequence of layers in the cave.

They were also analyzed by a second method to confirm the results.

“Quartz particles in sand have a built-in geological clock that begins to run when they enter a cave,” said Professor Ari Matmon, director of the Institute of Earth Sciences at Hebrew University. “In our lab, we are able to measure the concentrations of specific isotopes in these particles and deduce the time that has elapsed since these grains of sand entered the cave.”

The results of the study have far-reaching implications for better understanding not only the vicissitudes of Wonderwerk Cave and ancient human evolution, but also the current challenges, the press release said.

“With a firmly established timescale for Wonderwerk Cave, we can continue to study the link between human evolution and climate change and the changing way of life of our early human ancestors,” said Professor Michael Chazan of the University of Toronto and Liora Kolska Horwitz of the Hebrew The University’s National Natural History Collections said in a joint statement.