Archaeologists digging at a site on the southern coast of South Africa have found a trove of sophisticated stone tools they believe were made 50,000 years before the technology to create them emerged in Europe and other regions of Africa.

The finding, reported in the journal Nature, could mean that the first modern humans evolved where the Indian Ocean meets the Atlantic.

Small blades, called microliths, were unearthed at Pinnacle Point, about 500 kilometers west of Cape Town, and dated back 71,000 years.

The thin, 3-centimeter-long blades were carefully crafted so they could be glued into slots at the tip of arrows or spears. Such projectile weapons gave these early humans a significant advantage when facing a prey animal – or a competing human.

According to Arizona State University professor Curtis Marean, director of the Pinnacle Point excavation, the lethal technology “probably laid the foundation for the expansion out of Africa of modern humans and the extinction [of] our sister species, such as Neanderthals,” who did not have such projectile weapons

Previous digs have found similar stone weapons in use during an ice age 60,000 to 65,000 years ago. But the technology appeared in what archaeologists call a “flickering” pattern, with struggling cultures acquiring the weapons-making skills but failing to pass them on, and the technology seeming to vanish.

The new find means the method actually was passed on through generations and survived for more than 10,000 years. Professor Marean believes fieldwork in Africa will continue to push back in time the evidence for uniquely human behaviors.