6000-year old skull marks world’s oldest known tsunami victim
Bone fragments could provide clues to surviving future calamities, Jeff Glorfeld reports.
A partial human skull found in 1929 on the north coast of Papua New Guinea could belong to the world's oldest known tsunami victim, research suggests.
In a PLOS One paper published this week, an international team led by anthropologist Mark Golitko from the University of Notre Dame, in Indiana, US, presents evidence that the skull, found in a mangrove tidal area outside the town of Aitape, had been subjected to a violent tsunami that struck the coast about 6000 years ago.
The skull piece was originally found by noted Australian geologist Paul Hossfeld and was originally thought to belong to Homo erectus, dating from between 1.9 million and 143,000 years ago. Recent radiocarbon dating, however, reveals it to be much younger, placing it firmly in the mid-Holocene period.
Golitko and his team travelled to where the skull had been found, near a place Hossfeld had called Paniri Creek, to analyse the area’s soil for clues about what killed this person, and to learn more about the geological history of the region.
In testing sediments to determine grain size and geochemistry, they found diatoms, single-celled micro-algae that are among the most common types of phytoplankton, and which can be read as sensitive environmental indicators of water conditions.
"Diatoms make little silica shells around themselves, and when they die, those sink to the bottom," Golitko explains.
"So we put the sediment under a microscope and counted these diatoms, and it more or less tells you about the temperature, salinity and how energetic the water was that they were living in.”
He says the sediments in which the Aitape skull was found had only marine diatoms in them, meaning they’d been inundated by ocean water. Further, he says they found tiny specks of silica -- which indicated the diatoms had been smashed apart “really high-energy ocean water”.
The high-energy water, Golitko says, combined with chemical signatures and specific sediment grain sizes, all indicate the presence of a tsunami at the time the skull was buried. It's possible that it had been buried previously and was washed out as the tidal wave came across, but based on observations arising from a 1988 tsunami in the same area, this is unlikely.
Golitko hopes this study can help start a conversation about how people adapt and thrive in coastlands that are subject to tropical storms, earthquakes and tsunamis. The Aitape region has endured several tsunamis; the most recent killing more than 2000 people.
People likely started moving from the mountains to the coastlines in the region about 6000 years ago, he says.
And although they entered “ this super risky environment”, people seem to have lived there more or less continuously ever since.
"So they obviously come up with strategies for dealing with these risks, which could be very pertinent for thinking about what's going to be happening in the next couple hundred years,” says Golitko.
“It's the next challenge to look at how people were living in that area and how they're responding to these risks as they start to move into these environments."