Scientists thought that modern humans emerged in eastern Africa tens of thousands of years ago. The conclusion was drawn from the traces of a volcanic eruption.
The remains of a person were discovered at the site near the river. The human fossils were thought to be around 195,000 years old. The remains are older than the volcanic eruption that hit the region 233,000 years ago, according to new research published in the journal Nature.
The oldest fossils ever found in Africa are more firmly believed to be among the 300,000-year-old ones found at the Jebel Irhoud site in Morocco. The Jebel Irhoud skulls are not the same as those of modern humans, so some scientists may argue that they are not Homo sapiens. The oldest dating of modern humans in Africa is said to be the new discovery.
See photos of our closest human ancestors.
The study co-author, Aurélien Mounier, a paleoanthropologist at the Musée, said that the fossils that are thought to belong to the early stages of Homo sapiens are different. It is the oldest unchallenged Homo sapiens in Africa.
The ancient human remains are inside the layers of the Omo Kibish formation. The image is from Céline Vidal.
The remains were found in the East African rift valley, which is an active continental rift zone where the African plate is in the process of splitting into two smaller plates. Despite discovering the fossils more than 50 years ago, scientists have found it difficult to give the age of the Omo I. The fossils lacked nearby stone artifacts or fauna that could be dated, and the ash they were buried under was too fine-grained for radiometry.
The researchers collected samples from the Shala volcano and grinded them down until they were less than a millimeter in size. The researchers were able to confirm that both the pumice and the ash came from the same eruption by performing a chemical analysis on the pumice and comparing it to the ash layer above where the fossils were found. The fossils below the ash are at least the same age as the pumice samples, which are 233,000 years old.
The age of the Shala eruption wasn't known until the lead author, a volcanologist at Cambridge University, found a geochemical match. I sent the samples of Shala volcano to our colleagues in Glasgow so they could measure the age of the rocks. I was excited when I found out that the oldest Homo sapiens from the region was older than I had thought.
It is likely that some of humanity's earliest ancestors lived in a geologically active rift valley, according to a volcanologist at Cambridge University. The 4,350-mile-across (7,000 km) Great Rift valley, which is just a small part of the East African Rift valley, served as an enormous migration corridor for humans.
The researchers still need to find a maximum age for both the fossils and the wider emergence of Homo sapiens in eastern Africa despite finding the minimum age. They plan to link more buried ash to more eruptions from the region to give them a better idea of the geological history of the area.
The challenge of providing a maximum age for the emergence of Homo sapiens in eastern Africa remains, despite the fact that our forensic approach provides a new minimum age. It is possible that new finds and studies may extend the age of our species even further back in time.
Live Science published the original article.
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