In South Africa, close to gold reserves, researchers found remnants of the earliest known glaciers in the world. According to the experts, the glacial deposits are 2.9 billion years old. The research, which was published in the journal Geochemical Perspectives Letters, also shows that the region was either closer to the Earth’s poles at the time or that there were continental ice sheets there.
How was the research done?
Researchers Professor Axel Hofmann of the University of Johannesburg and Professor Ilya Bindeman of the University of Oregon carried out the research. The researchers uncovered shale deposits and examined core samples taken from the strata underneath the richest gold resources in the world in South Africa.
The Kaapvaal Craton in South Africa’s field sites yielded samples that were reportedly a part of the Pongola Supergroup, one of the largest and best-preserved volcano-sedimentary successions that was created during the Mesoarchaean period (3.2 to 2.8 billion years ago).
The researchers also employed triple oxygen isotope analysis to analyze core samples from the same area to ascertain the climatic circumstances that existed at the time that sediments were created. Three different oxygen isotopes or forms that are present in the sediment are measured using this technique.
On what they discovered
The discovery by the scientists that several isotopes in their samples matched those typical of icy temperatures implies that the environment must have been chilly at the time the rocks were deposited, indicating the existence of ice.
In addition, they uncovered the oldest known fossilized glacial moraines, which, according to Bindeman, are “basically the debris left by a glacier as it gradually melts and contracts,” adding, “These are the oldest moraine deposits ever found.”
What more does the research indicate?
These glacial remnants may contain information on the climate and geology of Earth at this time. The authors of the study propose several hypotheses, one of which is that this region of South Africa may have been near one of the poles 2.9 billion years ago.
A “snowball Earth” epoch, which was characterized by low atmospheric concentrations of greenhouse gases like carbon dioxide and methane and resulted in a “reverse greenhouse effect” that caused much of the world to freeze, is another possibility, according to Hofmann.
“Scientists think that this might have occurred a few times in the recent past. If so, this would mark the beginning of a significant global cooling era. Both scenarios are intriguing from a scientific perspective, Hofmann continued.