A story told for generations by the Gunditjmara people of southern Australia is thought to describe a volcanic eruption. Now, dating of lava produced by a volcano thought to feature in the tale shows the account is 37,000 years old, quite likely making it the oldest tale on Earth.
The lava flows of southwestern Victoria mark it as a former volcanic province, but the timing of the last eruptions has been uncertain.
The traditional owners of the Budj Bim heritage area, the Gunditjmara, have an origins story about four giants who gave life and laws to the land. In the Dreaming, an ancestral being – Budj Bim – emerges from the ground to become a domed hill with lava spilling out of its head, while the story also includes references to the “land and trees dancing”. It's not hard to see how this could be a description of a major eruption, leading anthropologists to wonder if the Gunditjmara were living there at the time of the last eruption. The possibility gained a boost with the discovery in the 1940s of an ax beneath the most recent layer of ash.
Dr Erin Matchan of the University of Melbourne used 40Ar/39Ar to date the most recent eruptions from the Budj Bim and Tower Hill volcanoes. The technique relies on the fact potassium radioactively decays to argon-39, so as time goes on potassium-rich rocks the amount of argon-39 builds up relative to the more common argon-40. Advances in mass spectrometry have recently made this technique much more widely available for dating volcanic rocks. In the journal Geology, she reports they released lava and ash respectively around 37,000 years ago, with an uncertainty of 3,100 years.
If the Gunditjmara story really does describe one of these eruptions, it is almost certainly the oldest surviving story whose origins we can identify.
It might seem impossible that eye-witness accounts could survive over such a vast sweep of time, even modified into myth. However, around much of coastal Australia Aboriginal stories refer to lands that were overwhelmed by rising seas, matching events that happened 7,000 years ago. An account of a volcanic eruption in northern Australia appears to be from the same time.
Matchan thinks the four giants story is five times older, but if 7,000 is possible, why not 30,000 more? The hardest period for the story's survival would have been the last two centuries, during which Indigenous Australians were banned from speaking their own language, and frequently had their children stolen by white authorities.
Matchan pointed out to IFLScience it is well established that Indigenous Australians have been in south-eastern Australia for at least 40,000 years, so habitation of the Gunditjmara lands almost certainly stretches back that far. However, aside from the ax and one profoundly mysterious 120,000-year-old possible fireplace and midden all the evidence of human occupation comes from the last 13,000 years.
Matchan and her co-authors admit the evidence for the origins of the four giants story is far from conclusive. It might not describe a volcanic eruption at all. Or perhaps it was inherited from people fleeing the eruption of Mount Gambier, 130 kilometers (80 miles) northwest, which could be as little as 5,000 years old.
Nevertheless, there is mitogenomic evidence that Indigenous peoples may have remained in discrete geographical areas for tens of thousands of years following initial migration from Northern Australia. A people forced into a major migration by a local disaster would be expected to have interbred much more with their neighbors. The area's remarkable eel traps, the world's oldest aquaculture remnants are part of the Gunditjmara culture, indicating their presence in the area for at least 6,600 years.
Proving the four giants story really does describe the eruption may never be possible, but recovering additional relics from before the eruptions might tell us a lot about the people who inhabited the area. The reason nothing new has been found for 70 years, Matchan says, “Is probably because no one has really looked. The ax was a chance find by a farmer digging post holes, rather than part of a deliberate search."