Notions of hearth and home are fundamental to our conception of humanity, stretching as far back to prehistoric civilization. Excavations at Wonderwerk Cave in South Africa’s Kalahari Desert have led researchers to determine that a cave held human occupants as long as two million years ago, making it the world’s oldest home. Like other recent discoveries in the South African Kalahari Desert region, the new chronology of Wonderwerk Cave — made possible by magnetostratigraphy (used to date sediment) and cosmogenic aging techniques — has expanded our understanding of life at the origins of human civilization.
“We can now say with confidence that our human ancestors were making simple Oldowan stone tools inside the Wonderwerk Cave 1.8 million years ago,” said researcher Ron Shaar, lead author on a paper presented by a team of geologists and archaeologists from the University of Toronto and the Hebrew University in Jerusalem, in a statement.
A handaxe from the Achelean layers at Wonderwerk. In the background is the cave entrance. 
The Wonderwerk Cave entrance 
A 3D scan of the excavated area that was sampled for dating (courtesy Zamani Project, University of Cape Town) 
Ron Shaar taking samples for paleomagnestisim
This statement distills the incredibly complex findings published this month in Quaternary Science Reviews, and explains the processes by which researchers were able to analyze and date some of their findings, which included establishing the shift from Oldowan tools (mainly sharp flakes and chopping tools) to early hand axes over one million years ago, and to date the use of fire by our prehistoric ancestors to one million years ago.
“We carefully removed hundreds of tiny sediment samples from the cave walls and measured their magnetic signal,” described Shaar. “Our lab analysis showed that some of the samples were magnetized to the south instead of the north, which is the direction of today’s magnetic field. Since the exact timing of these magnetic ‘reversals’ is globally recognized, it gave us clues to the antiquity of the entire sequence of layers in the cave.”
While the analysis has taken place on a particulate level, the conclusions are huge for paleoanthropology, which seeks to understand human evolution. For example, the presence of fire remnants (such as burnt bone, sediment, tools, and ash) inside the cave firmly establishes use of fire as a tool in prehistoric humans, in contrast to evidence of early fire use from open-air sites, where naturally occurring wildfire might also be responsible.
Inside the cave 
178 soils samples passed the rigorous selection criteria, revealing evidence encompassing 14 cosmogenic burial ages.
As with other archaeological projects in the area, the Wonderwerk Cave Research Project says it also has a duty to respect the cave’s spiritual significance to ancestral and contemporary residents of the area. In an effort to do this, the team has established outreach and working partnerships with neighboring towns to “develop the educational and cultural potential of this place.”
