Africa-Press – Liberia. Scientists already believe the Earth was completely or mostly covered in ice 650 million years ago. Now, they have found evidence there may have been a much earlier ice age, roughly 2.9 billion years ago.
Scientists have discovered evidence that glaciers may have been present in South Africa 2.9 billion years ago, indicating there may have been a global glacial period earlier than previously thought.
A team of scientists led by University of Johannesburg archaean geologist Axel Hofmann analyzed bed rocks under the world’s largest goldmine near South Africa’s east coast. The layers of rocks, dubbed the Pongola Supergroup, are unique in that they have been barely disturbed since they formed billions of years ago.
Scientists already believe the Earth was completely or mostly covered in ice 650 million years ago. Now, they have found evidence there may have been a much earlier ice age, roughly 2.9 billion years ago.
Scientists have discovered evidence that glaciers may have been present in South Africa 2.9 billion years ago, indicating there may have been a global glacial period earlier than previously thought.
A team of scientists led by University of Johannesburg archaean geologist Axel Hofmann analyzed bed rocks under the world’s largest goldmine near South Africa’s east coast. The layers of rocks, dubbed the Pongola Supergroup, are unique in that they have been barely disturbed since they formed billions of years ago.
The study found that samples of sandstone and shale from the area exhibited lower levels of oxygen-18 and higher levels of oxygen-17, indicating the rocks formed under cold conditions.
This would indicate a gradual climatic cooling of surface environments on Earth and points to glaciers in South Africa billions of years ago. Scientists know of at least two periods in which the Earth completely or nearly froze over, the most recent being 650 million years ago in a period called the Marinoan glaciation. But researchers are still unsure if the Earth was a frozen wasteland at the time, or if it had habitable areas near the equator and other warm spots.
If the evidence in South Africa confirms another glacial period, it will be the earliest known glacial period in Earth’s history. But the researchers also pointed to another possibility: continental shift. If South Africa was closer to the Earth’s poles, that could also explain the evidence of glaciers.
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