?This man drowned 5,000 years ago. How do we know that
Ancient human remains from Chile's north coast have been analyzed using a modern forensic technique that identifies drowning victims. Researchers found evidence for a fisherman who likely drowned in the cold waters of the Pacific 5,000 years ago.
By modifying a modern forensic technique, researchers were able to determine that skeletal remains in Chile belonged to a likely fisherman who drowned in the Pacific thousands of years ago.
Some 5,000 years ago on the coast of Chile’s Atacama Desert, a fisherman drowned in the cold waters of the Pacific. It’s the life-and-death story of an individual who lived millennia ago, and one that researchers are now able to tell, thanks to a twist on a modern forensic technique.
The “diatom test,” used today to identify victims of drowning, relies on what happens to the human body during the event: Inhaled water ruptures the lungs and is pumped around the dying body, including along tiny capillaries that go through bones and into the marrow.
The male adult was likely a fisherman due to signs of frequent rowing activity on his bones and an almost exclusively marine diet. He was buried in an unusual manner, with limbs splayed and shells replacing missing neck vertebrae.
Forensic scientists examine the marrow of the dead to look for diatoms—microscopic algae with shells of silica—that are characteristically found in drowning victims. Now, researchers writing in the Journal of Archaeological Science have confirmed that the diatom test can be performed on human remains dating back thousands of years—a breakthrough that may offer a new way of investigating prehistoric tsunamis and identifying their victims.
Microscopic marine particles and a parasitic egg were found during the analysis.
“We know that tsunamis cause many victims, but where are they in prehistoric times? asks James Goff , a geologist at the University of Southampton in the UK, one of the authors of the new study.
He is an expert in ancient tsunamis and has found the perfect candidate to test his method: a skeleton excavated from a 5,500-year-old tomb at Capoca 1, an archaeological site on the northern coast of the Atacama Desert, Chile. .
The tomb was excavated in 2016 by Pedro Andrade , another study author, an anthropologist at the University of Concepción. He identified a skeleton there, probably that of a fisherman in view of the wear of his bones, indicating frequent rowing activity. In addition, an isotopic analysis revealed that his diet was based mainly on products from the sea.
The man's skeleton was almost intact. However, some cervical vertebrae were missing and had been replaced in the grave by large shells. The man also appeared to have been buried with his arms pointing in opposite directions and one leg sticking out.
Goff says the skeleton was the ideal sample to conduct a proof-of-concept test of diatom testing on archaeological remains. “We knew that this person was a fisherman, based on his bone structure and that his burial had been somewhat strange. Let's see if he had drowned, ”he announces.
The parasitic egg revealed by the modified method.
ONE DEATH BY DROWNING
Goff and his colleagues made thousands of marrow electron microscope images of the largest bones in the Capoca 1 skeleton, which were the least likely to have been contaminated by outside elements after death.
To perform a modern diatom test, one must remove the marrow from the bone and add chemicals to reveal the diatoms. The modification made by Mr. Goff keeps the marrow in its place and involves fewer chemical elements. This means that other marine particles are preserved, not just diatoms. Strangely, the researchers found no fossilized diatoms in the skeleton studied. The exact reason for this lack is still unclear. Nevertheless, they highlighted the presence of fossilized seaweed, parasitic eggs and sediments that the standard diatom test could not have detected.
Researcher James Goff studies the remains of the fisherman. Scientists hope that this major advance in the forensic field will allow them to identify the victims of ancient tsunamis.
The team was thus able to confirm that the fisherman died by drowning. In contrast, the researchers found no such signs in two other sets of human remains excavated nearby. They therefore believe that the man probably died during a fishing accident rather than during a tsunami.
The ability to determine whether people who lived in prehistoric times died by drowning will be a major advance for archaeological research on tsunamis. “There are many massive burial sites along the coasts and if we determine that these people drowned, we can say that they probably died in a tsunami,” Goff said. “We could then look at other artifacts and better understand how people lived and died along the coasts in prehistoric times. »
Tsunamis certainly had a major impact on ancient coastal communities, but they can be difficult to identify, says Beverly Goodman-Tchernov , professor of marine geosciences at the University of Haifa in Israel, also a National Geographic Explorer. She and her colleagues have already planned to use the modified diatom test on the bones of a man and a dog both drowned in a tsunami after the volcanic eruption at Thera 3,600 years ago.
Ms. Goodman points out that not all tsunami victims necessarily died by drowning. They may also have died of head trauma during the event. Still, the modified diatom test could be an important piece of the puzzle. “If there is a mass grave, we have to rely on a lot of evidence to support that a tsunami has occurred,” she continues. “[This technique] would definitely help us support the hypothesis that a tsunami occurred. »
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