Australia's deepest human history
At the base of the Arnhem Land escarpment in Northern Australia is Madjedbebe, a sandstone rock shelter that contains the oldest evidence of human occupation on the continent. Excavations have showed that human arrival occurred back the timeline of human arrival by at least 15,000 years. The deepest layers of sediment contain stone tools and other artifacts dated to a minimum of 65,000 years ago.
Archaeologists used a technique called Optically Stimulated Luminescence (OSL) to determine the age of the site. This method measures the last time individual grains of sand in the sediment were exposed to sunlight. The excavations, conducted in partnership with the traditional owners, the Mirarr people, found more than 10,000 artifacts in the lowest occupation layer alone. These objects were buried 2.6 meters below the current surface, in a dense band of sandy sediment. The findings establish a new minimum age for the dispersal of modern humans out of Africa and their migration across Southeast Asia to Australia.
A Pleistocene toolkit
The artifacts at Madjedbebe show a set of technologies. Among the most significant finds are the world's oldest known ground-edge axes, far older than similar tools found elsewhere. While ground-edge axes appeared in Japan around 35,000 years ago, they did not become common in most parts of the world until the advent of agriculture, about 10,000 years ago.
The site also contains the oldest seed-grinding tools in Australia. Microscopic analysis of these grinding stones indicates they were used to process seeds, tubers, and pandanus nuts, providing direct evidence of plant-based foods consumed by the earliest Australians. Alongside the tools, large quantities of ground ochre were discovered. Some pieces were used like crayons, and the discovery of reflective pigments represents one of the earliest known uses of such materials in the world. The toolkit also included finely made stone points that may have been used as spear tips. This collection of artifacts shows the early inhabitants were innovators who adapted their technology to exploit the resources of a new land.