Modern humans appeared in eastern Africa at least 38,000 years earlier than scientists had previously thought.The conclusion was drawn from the traces of a huge volcanic eruption used on the earliest indisputable dates. Homo sapiens fossil.
An archaeological site called Omo I was discovered in the 1960s at the Omoki Bish site near the Omo River in Ethiopia. Earlier estimates were that human fossils were about 195,000 years old.Now, a new study published in the journal on January 12th. Nature, Another story — the ruins are older than the huge volcanic eruption that shook the area about 233,000 years ago.
New estimates put fossils even more firmly in the oldest Homo sapiens It remains undiscovered in Africa and is second only to the 300,000-year-old specimen found at the Jebel Irhoud archaeological site in Morocco in 2017. However, the Jebel Irhoud skull is sufficiently different in physical properties from the modern human skull, and some scientists disagree with the classification.that’s why Homo sapiens.. This means that new discoveries represent the oldest, undisputed dating of modern humans in Africa.
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“Unlike other middlemen Pleistocene Fossils believed to belong to the early stages of Homo sapiens The pedigree, OmoI, has distinct modern human characteristics such as a tall, spherical skull vault and chin, “said Aurélien Mounier, a research co-author and paleoanthropologist at the Homme Museum in Paris. .. Said in a statementThe vault of the spherical skull is called the space inside the skull where the brain is. “New date quotes effectively make it the oldest unchallenged one. Homo sapiens In Africa. “
The ruins were found in the Great Rift Valley of East Africa. The East African Rift Valley is an active continental rift zone inhabited by Africans. Structural plate It is in the process of splitting into two smaller plates, the Somali plate and the Nubian plate. Despite discovering fossils over 60 years ago, scientists have found it difficult to keep Omo I at a decisive age. The fossils had no dating nearby stone relics or fauna, and the ash they were buried in was too fine for radiometric dating. This is a method of quantifying the amount of a particular radioisotope. element The number of neutrons in the nucleus is different), known decay rate.
To avoid these problems, researchers collected pumice samples from Shala volcano, more than 248 miles (400 km) away, and crushed them to a size less than 1 millimeter. By performing a chemical analysis of the pumice found in the volcano and comparing it to the ash layer of the sediment above where the fossil was found, researchers were able to confirm that both shared the same chemical composition. Same eruption. The pumice sample and ash layer were found to be approximately 233,000 years old. That is, the fossils of Omo I under the ashes are at least the same age or older.
“We first discovered that there was a geochemical consensus, but we weren’t the age of the Shara eruption,” Celine Vidal, the lead author of the University of Cambridge volcanologist, said in a statement. “I immediately sent a sample of Shara volcano to a colleague in Glasgow so that I could date the rocks. I received the results and found that the oldest Homo sapiens in the area was older than previously expected. When I was really excited .. “
Clive Oppenheimer, a volcanologist at the University of Cambridge, said in a statement that it would not be a coincidence that some of humanity’s earliest ancestors lived in the rift zone. Crustal movement activity not only created lakes to collect stormwater and provided freshwater, but also attracted animals to hunt. The 4,350-mile (7,000 km) Great Rift Valley, which is only part of the East African Rift Valley, served as a huge mobile corridor for humans and animals traveling north from Lebanon in the north. Mozambique in the south.
Despite finding the minimum age of the Omo I sample, researchers need to find the maximum age of both these fossils and the broader appearance of Homo sapiens in East Africa. They do this by linking more buried ash to more eruptions from volcanoes around the area and giving a stronger geological timeline for the fossil-deposited sedimentary layers of the area. I am planning.
“Our forensic approach provides Homo sapiens in eastern Africa with a new minimum age, but the challenge of providing the upper limit of their emergence, the highest age, which is widely believed to have occurred in the region, remains. It remains, “co-author Christine Lane, a geochronologist at the University of Cambridge, said in a statement. “New discoveries and new research may allow us to go back in age to our species.”
Originally published on Live Science.
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