For our new paper, we decided to further test these estimates using uranium-series (U-series) dating of megafauna fossils. The U-series dating technique has been refined over several decades. It allowed us to directly date megafauna fossils from the Papuan Highlands for the first time.
Our
research suggests the fossils date to between 22,000 and 27,000 years ago – which is very close to Mountain’s original estimates and the more recent accelerated mass spectrometry dates.
The U-series dating provides minimum age estimates, which means the fossils
could be older. But since our estimates are supported by previous accelerated mass spectrometry dating, collectively the data provide a compelling case for the existence of megafauna in Sahul as recently as 25,000 years ago.
This contradicts the persisting theory these animals were extinct by 42,000 years ago.
Our research also extends the period of overlap between megafauna and people. If the earliest dates for people in Sahul go back 65,000 years, this implies some 40,000 years of overlap.
Adding to this,
recent work at the Willandra Lakes in NSW and the Seton Rockshelter at Kangaroo Island also estimates Sahul’s megafauna were alive some 30,000 years ago.
