Surabaya – Scientists find the oldest glacier. Interestingly, the glacier was found under the gold fields of South Africa.
The glacial deposits that are so durable are beneath the largest gold deposits in the world. Because of this, South Africa was thought to have been close to the South Pole.
The discovery of this fact helped to convince how the environmental conditions were in the early days of life on Earth. These findings have been published in the journal Geochemical Perspectives Letters under the title Earth’s first glaciation at 2.9 Ga revealed by triple oxygen isotopes.
Indeed, basically the conditions on Earth at that time were still not widely known. However, these 2.9 billion year old glacial remains could provide evidence for a number of theories about conditions at the time.
“It could be that the area was close to the poles. Another possibility is that the whole Earth was in a ‘snowball’ period when concentrations of CO2 and CH4 caused the reverse greenhouse effect and caused most of the planet to freeze,” explains Professor Axel Hoffman from the Department of Geology, The University of Johannesburg, South Africa is involved in the discovery.
“Scientists believe that such events may have occurred several times in the past. And if so, then this period is the earliest recorded global cooling period,” he said again, quoted from IFL Science.
Along with physical evidence of fossilized glacial moraines, scientists also analyzed oxygen isotope concentrations in ancient rocks to determine the climatic conditions at which they were deposited. According to the Encyclopaedia Britannica, moraines are accumulations of rock debris carried or deposited by glaciers.
“We looked at the relative amounts of the three oxygen isotopes, 16O, 17O, and 18O. These are all types of oxygen but have slightly different weights. We found that these rocks have very low amounts of 18O, and very high amounts of 17O, indicating that they form at cold temperatures,” explained another author, Professor Ilya Bindeman.
“Geochemical evidence coupled with moraine evidence, and which means it’s a glacier, is the oldest glacier found on Earth,” said the professor at the Department of Earth Sciences, University of Oregon, United States.
Hofman added that the location of the find, which is under the largest gold deposit on Earth, could also attract further investigation.
“It is possible that the change from the freezing period to the greenhouse effect has helped the formation of these gold deposits, but this needs to be confirmed and requires further research,” he explained.
Using three oxygen isotope analyzes like this could open new avenues for finding evidence of early Earth glaciation. Findings like these introduce new avenues for investigating Earth’s climate history.
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(nah/iwd)
2023-07-16 21:00:52
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