Kiwis find ‘oldest tsunami victim’
Analysis of 6000year-old skull points to tidal wave as cause of death
Kiwi researchers have helped reveal what is thought to be the world’s oldest known tsunami victim.
Geological analysis of a site where part of a 6000-year-old human skull was discovered in Papua New Guinea in 1929 has shown how the person probably died in a tsunami.
Researchers behind the study, published today in the journal PLOS
ONE, found that the place where the skull was unearthed was a coastal lagoon that was inundated by a large tsunami about 6000 years ago.
It was likely to have been similar to the tsunami that struck nearby in 1998, killing more than 2000 people.
“We conclude that this person who died there so long ago is probably the oldest known tsunami victim in the world,” said the study’s author, Honorary Professor James Goff, of the University of New South Wales.
The partially preserved skull was discovered almost 90 years ago by Australian geologist Paul Hossfeld at a site which is about 12km inland from the northern coast of PNG, near the modern town of Aitape.
Dr Ethan Cochrane, a senior lecturer in anthropology at the University of Auckland, jointly designed the research and led the field team with colleagues from New Zealand, PNG, Australia and the United States.
“We tramped several kilometres up Paniri Creek leading into the Torricelli mountains to find the area where the skull was originally retrieved,” Cochrane said.
“[Hossfeld] simply took the skull from exposed geological deposits, so our goal was to acquire sediment and biological samples from the deposits to learn more about the natural environments in which the individual died thousands of years ago.”
Tests on the sediment looked at its grain size and geochemistry.
The team found the microscopic silica shells of diatoms, single-cell organisms that are indicators of water characteristics such as temperature, salinity, and amount of movement.
“We used the diatoms to learn more about the water in the area around the time of the individual’s death,” Cochrane said. “The sediments that the Aitape skull was in have pure marine diatoms in them, which indicates ocean water was inundating the area, which currently is 12km inland.
“It’s also really high-energy ocean water — high-energy enough for these little tiny specks of silica that the diatoms build to be broken as they’re washing in from the sea.”
The high-energy water combined with chemical signatures and specific sediment grain sizes all indicated the presence of a tsunami at the time the skull was buried, Cochrane said.
“It’s possible that the skull was buried before and it was washed out as the tsunami came across, but we don’t think that’s likely.”