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Homo habilis (probably) was here

According to a new dating, tools found in the Jordan Valley may be the earliest evidence of the presence of humans outside of Africa

by Tamara Traubman

Two geologists, who used an advanced dating method, identified the age of a layer of rock at an ancient site in the Jordan Valley, in which tools made by ancient humans were discovered in the past. According to the research findings, the tools found at the site, known as "Ark El Ahmar", near Kibbutz Gesher, were created almost two million years ago, and according to the researchers - Hagi Ron, professor of geology at the Hebrew University and the Geophysical Institute, and Shaul Levy, professor emeritus at Oregon State University in the United States - These are the earliest evidence of the presence of humans outside of Africa, where the first man evolved. The researchers describe their findings in the current issue of the journal "Geology

The Mark El Ahmar tools are similar in shape to the tools produced 2.5-2 million years ago in Africa by the first humans. Together with the age of the layer in which the vessels were found, the possibility arises that the Mark al-Ahmar people were ancient immigrants, who came from Africa to the Middle East. This contradicts the popular belief, according to which the first man to come out of Africa was the descendant of Homo habilis, Homo erectus. However, the paleontologist excavating the site, Prof. Eitan Chernov from the Hebrew University, says that the findings do indeed "add weight" to the claim that Homo habilis was the first to leave Africa and that one of the first stops in its spread was the Middle East, but he insists on being cautious. According to him, so far he has discovered few siege tools at the site. He wants to find more tools before he comes out with a "sensational announcement", which will change the scientists' perception of the homo abilis.

The arid area where the vessels were discovered was once a fertile area covered with lakes. The vessels and bones of animals sank to the bottom of the lake and were preserved in the resulting sediment layer. Ron says that the first time scientists tried to identify the age of Ark El Ahmar was in the seventies. Chernov, followed by Prof. Aharon Horvitz from Tel Aviv University, then based themselves on animal fossils and plant pollen discovered at the site. Their conclusion was that the site is approximately two million years old. But according to Ron, the range of uncertainty obtained with this dating method was enormous, and the estimated age determined ranged from three million to a million and a half years.

About ten years ago, Ron, together with Dr. Shmulik Marko and Doron Brown, dated Ark El Ahmar using the same method used in the current study, but with a less high degree of resolution. The results of the test revealed that the vessels are about two million years old, with a possible deviation of up to 400 thousand years. "When it comes to human migration, it's still an age range that can have a huge meaning. This can be the difference between one species and another," says Ron.

In the current study, Ron and Levy used the same method, known as "magneto-stratigraphy". This method is based on the fact that the Earth's magnetic field is dynamic: once every few hundred thousand years, randomly, the Earth's magnetic field reverses, and the South Pole becomes the North Pole, and vice versa.

These reversals remain recorded in the rocks. "When rocks are formed, the properties of the Earth's magnetic field are recorded in them, like on a tape. It's as if inside the rock there are lots of little compasses, which freeze as soon as the rock is formed and preserve the direction of the magnetic field. This information can be preserved in rock for billions of years," says Ron.

Today it is known when each magnetic reversal that occurred on Earth began and ended. The team compared the data obtained from Mark El Ahmar to the known dates of magnetic reversals, and thus was able to conclude that the layer of rock in which the tools were discovered ranges between 1.96 million years and 1.78 million years.

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