Eastern Africa was home to modern people 38,000 years earlier than previously believed.

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A thick layer of soot from a significant volcanic outburst covered the bones.

At least 38,000 years earlier than previously assumed, modern humans first appeared in eastern Africa. An enormous volcanic eruption was traced back to the first known fossils of Homo sapiens.

Known as Omo I, the skeletal remains was found in the Omo Kibish area of Ethiopia in the 1960s. The human fossils were previously thought to be 195,000 years old. After a massive volcanic eruption devastated the region around 233,000 years ago, new research published in the journal Nature on Jan. 12 suggests the ruins may be far older.

Regarding Africa's earliest Homo sapiens remains, the revised estimate places the fossils second only to the 300,000-year-old specimens discovered at the Jebel Irhoud site in Morocco in 2017. Despite the differences in physical traits, some scientists disagree that the Jebel Irhoud skulls should be classified as Homo sapiens. New findings indicate that this is the earliest known date of modern humans in Africa that has not been challenged.

Aurélien Mounier, a paleoanthropologist at the Musée de l'Homme in Paris and study co-author, said that unlike other Middle Pleistocene fossils thought to belong to the early stages of the Homo sapiens lineage, Omo I "possesses unequivocal modern human characteristics," such as a tall and rounded cranial vault and a chin. De facto, the revised dating estimates make these Homo sapiens the oldest in Africa.

An ancient human skeleton has been preserved in the Omo Kibish formation in southern Ethiopia's Omo Valley region. (Céline Vidal is the photographer.)

The East African Rift Valley, where the Somali Plate and the Nubian Plate are separating from the African tectonic plate, is where the remains were discovered. Although the fossils were found more than 50 years ago, scientists are still unable to date the Omo I remains accurately. Radiometry, a technique that measures the number of radioactive isotopes (different versions of an element with a different number of neutrons in the nucleus) with known decay rates, was unable to date the fossils because there were no nearby stone artifacts or fauna. The ash under which they were buried was also too finely-grained for radiometry.

Researchers collected pumice samples from the Shala volcano, more than 248 miles away (400 kilometers), and ground them down to less than a millimeter in size. Analysis of the pumice found at Volcano Crater and silt above where fossils were located allowed researchers to determine that both pumice and ash were from the same eruption based on their chemical composition. The pumice samples and the ash layer were discovered to be approximately 233,000 years old, meaning that the Omo I fossils found underneath the ash is at least as old as the ash, possibly even more.

A geochemical match was identified, but the age of the Shala eruption could not be determined, according to lead author Céline Vidal, a volcanologist at Cambridge University. "I sent the rocks from the Shala volcano to our colleagues in Glasgow immediately so that they could determine their age. I was delighted to learn the findings, which revealed that the oldest Homo sapiens in the region was significantly older than previously thought."

Clive Oppenheimer, a volcanologist at Cambridge University, stated in the statement that some of humanity's earliest ancestors lived in a geologically active rift valley. In addition to providing fresh water and attracting animals, the Great Rift Valley, which includes the East African Rift Valley, served as a vast migration corridor for humans and animals that ran from Lebanon in the north to Mozambique in the southernmost region.

Researchers still need to determine the maximum age of the Omo I samples and the broader appearance of Homo sapiens in eastern Africa despite having established the minimum age of these fossils. They intend to do this by establishing a more precise geological date for the sedimentary layers in the area where fossils have been deposited by connecting more buried ash to more eruptions from volcanoes.

Our forensic technique provides a new minimum age for the advent of Homo sapiens in eastern Africa, which is commonly considered to have occurred in this region. Still, the problem remains to provide a cap, a maximum age, for their appearance. According to one researcher, "discoveries and investigations could push the timeline of our species even further back."

Reference : https://www.livescience.com/volcano-reveals-modern-humans-older-than-thought

Image source : https://pixabay.com/id/vectors/vintage-kerangka-vintage-ilustrasi-2417799/

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