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SYDNEY, Nov. 22 (Xinhua) – Research published Thursday by an international group of scientists, including Australians, provides insight into how and when our ancestors evolved, and even what the climate was like at the time. .
It has long been recognized that the origins of humanity are in Africa and that is what fossils recovered from the caves called "Cradle of Humankind" in South Africa have told us.
However, until now, scientists have struggled to create a clear chronology of fossils because of the lack of proper dating methods.
Professor Andy Herries of La Trobe University, who conducted research at the sites, said that "if the South African record was the first to show that Africa is the point of departure," he said. Origin of humans, the complexity of the caves and the difficulty in dating them made the record hard to interpret. "
"In this study, we show that flow stones in caves can act almost like the volcanic layers of East Africa, forming simultaneously in different caves, allowing us to directly link their sequences and fossils to a regional sequence, "he said.
The world-famous Cradle of Humankind caves have produced nearly 40% of all known fossils of ancestors, including the famous skull of Australopithecus africanus, nicknamed Mrs. Ples.
According to Robyn Pickering, principal researcher at the University of Cape Town, the team's dating provides "a model to explain the age of all the fossils of the entire region" as well as to create an image climatic conditions of our ancestors.
"Flowstones are the key," said Pickering.
Flowstones are deposits of calcite or other carbonate minerals that form when water enters caverns.
"We know that important flow currents grow in caves only during wet periods, when it rains more outside the caves." In dating the flows, we now identify those periods of time. 39, precipitation increase, "said Pickering.
Using leaded uranium dating techniques developed at the University of Melbourne, the team analyzed 28 layers of Flowstone that are interspersed between fossil-rich sediments in eight caves located at the University of Melbourne. 39, inside the cradle – revealing that the age of fossils ranged between six and 1.3 million years ago.
"So we know that during the interim period, when the caves were open, the climate was drier and more like what we are currently experiencing," she said.
According to experts, this is a staggering breakthrough that greatly contributes to the recording of humanity by itself and to its understanding of the lives of common ancestors from which we come have evolved.
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