The 50,000-Year-Old Footprints Preserved in Volcanic Ash

Some 50,000 years ago, on the volcanic plains of western Victoria, a human hand pressed wet clay into a soft volcanic tuff and left its imprint. The footprint hardened into rock. It remains there today, beside the toe-prints of extinct giant marsupials, in a cave formed by a lava tube.

The Lava Tubes of the Western Volcanic Plain

Victoria's Western District is not what most people picture when they think of Australian geology. There are no red deserts or ancient cratons here. Instead, a 15,000-square-kilometre basalt plain stretches from Melbourne's western edge to the South Australian border, dotted with more than 400 volcanic vents. The youngest eruptions occurred just 5,000 years ago — yesterday, by geological time.

As lava flowed from these vents, the outer surface cooled and hardened while the molten interior continued to drain downhill. The result was a network of hollow basalt tunnels: lava tubes. Some of these tubes collapsed long ago, leaving shallow depressions or rubble-filled trenches. Others remained intact, sealed beneath the plain for millennia.

One such tube, at Budj Bim (formerly Mount Eccles), forms a cave known as the "Tunnel Cave" or, in the Gunditjmara language, the place of the spirit ancestors. It runs roughly 20 metres below the surface and extends for several hundred metres. The walls are smooth basalt. The floor is littered with fallen blocks. At the deepest point, the air is cold and still.

The Footprints in the Ash

In the 1970s, archaeologists exploring the lava tubes near Budj Bim made an unexpected discovery. On a floor of hardened volcanic ash inside one tube, they found human footprints — not just a few, but hundreds, pressed into the soft tuff and preserved when the ash dried and cemented. Radiocarbon dating of charcoal from the same layer placed the prints at around 50,000 years old.

These are among the oldest known human footprints outside Africa. They record the passage of children and adults, barefoot, moving through a dark tunnel. The prints are small — some belonging to toddlers — suggesting families travelled together through the volcanic landscape. Beside them lie the tracks of giant kangaroos, wombats the size of cars, and the clawed feet of the marsupial lion Thylacoleo carnifex.

The same lava that buried the land also preserved the moment of its crossing.

The ash that preserved the prints was itself a volcanic product — fine-grained tuff from a nearby eruption that blanketed the cave floor. Had the ash been thicker or thinner, had the footfalls been heavier or lighter, the record would have been lost. Instead, a single geological accident captured a human instant.

A Landscape of Wetlands and Fish Traps

The Gunditjmara people did not merely pass through this volcanic landscape. They lived with it, on it, and through it. The basalt plain is poorly drained — the dense lava rock prevents water from percolating downward — so seasonal rainfall created a network of shallow lakes and swamps. The Gunditjmara engineered these wetlands.

They built channels, weirs, and stone-walled fish traps that directed eels and fish into holding ponds. The system is among the oldest known aquaculture operations in the world, dating back at least 6,600 years. The volcanic stone was not an obstacle; it was material. Basalt blocks were stacked without mortar into walls that still stand. The eels — short-finned eels that migrate from the ocean — were caught, smoked, and traded across the continent.

At Budj Bim, the lava flow itself created the conditions for this industry. The uneven basalt surface, riddled with depressions and cracks, formed natural basins. The Gunditjmara modified them. The result is a cultural landscape inscribed directly onto volcanic rock.

The Sleeping Volcanoes

The Western Volcanic Plain is classified as a dormant maar-volcanic field. The most recent eruption, at Mount Gambier just across the South Australian border, occurred roughly 5,000 years ago. Since the arrival of humans, no eruption has been witnessed or recorded. But the field is not extinct. Magma still sits beneath the plain. Seismic studies show a zone of partial melt at a depth of 30 to 40 kilometres.

The volcanoes that built this landscape are small — most rise less than 100 metres above the plain. They are scoria cones, maars, and lava shields, not the towering stratovolcanoes of the Pacific Ring of Fire. But their geological signature is unmistakable: the fresh, dark basalt, the unweathered flow tops, the gashes of red scoria where quarrying has cut into the cones.

In the Budj Bim lava tube, the footprints remain. They are now protected as part of the Budj Bim Cultural Landscape, a UNESCO World Heritage site. But they are vulnerable. The cave environment is delicate; changes in humidity or airflow can cause the ash to crack and flake. The prints that survived 50,000 years could be lost in a single season of neglect.

For now, they lie in the dark, still and cold, recording the moment when a family walked through a fresh volcanic tunnel, their children's feet pressing into ash that would outlast every living thing they knew.