An international team of scientists led by the University of Oregon has found evidence in South Africa that about 2.9 billion years ago, the Earth might have been almost entirely covered in ice. The related study was published in the journal Geochemical Perspectives LettersPublished by the European Geochemical Union (EAG).
“We found perfectly preserved glacial deposits near gold mines in South Africa. This area is one of the few sites that has survived virtually unchanged from early times. These deposits are petrified moraines, actually melted and melted,” said Ilya Bindeman, a professor at the University of Oregon at Eugene. “They are bits of rock left behind by a retreating glacier,” he said.
Glacial deposits were found beneath the Witwatersrand, the world’s largest deposit of gold ore. It is located southwest of Johannesburg (the capital of South Africa). Taking samples from a rock that looks like a glacial rock, the experts compared the number of isotopes in its composition. Experts analyzed the oxygen isotopes 16O, 17O and 18O. These molecules have different masses. Their number reflects the different total number of protons and neutrons in the atomic nucleus.
During the analysis, the scientists determined that the debris was deposited by glaciers. Evidence of this was the presence of small amounts of oxygen-18 and large amounts of oxygen-17 in the glaciers. This indicates sub-zero temperatures where glaciers form.
According to Bindemann, the moraine deposits found are the oldest of those previously studied. The researchers believe that the rocks they found may indicate the fact that 2.9 billion years ago, Earth experienced a global or partial glaciation, during which a significant part of the planet was covered with ice. It is also assumed that the region of petrified moraines was much closer to the pole three billion years ago. However, more research is needed to definitively determine this.
ancient scientists saidhow melting glaciers accelerate warming through methane emissions.