Ancient Glaciers From 2.9B Years Ago Still Intact Under Gold Deposits in Africa

In South Africa, beneath the greatest gold concentrations on earth, rocks have been found to contain remnants of the world's ancient glaciers, which date back 2.9 billion years.

Researchers Professor Axel Hofmann and Professor Ilya Bindeman have discovered evidence from relative oxygen isotope quantities in ancient rocks as well as tangible proof that demonstrates the existence of glaciers.

Well-Preserved Ancient Glaciers Underneath Africa

According to Bindeman, they discovered glacial deposits that were remarkably well-preserved not far from South Africa's gold fields. One of the few places on Earth still mostly unaltered and undamaged from the early Earth is this region. He asserts that these deposits are, in fact, fossilized remnants of glacial moraines, which essentially refer to the remnants left by a melting and shrinking glacier.

The oldest deposits of a moraine have ever been discovered. Additionally, they were able to link this to an examination of oxygen isotopes found in these rocks, which demonstrated that the environment at the time the rocks were deposited must have been frigid.

This is in line with a news release from the Goldsmith Conference that was released on Wednesday and appeared in EurekAlert.

According to Bindeman, they examined the relative concentrations of the oxygen isotopes 160, 170, and 180. All of these forms of oxygen differ only very slightly in weight. These rocks had extremely low levels of 180 and extremely high levels of 170, which revealed that they were created at frigid temperatures, which denotes ice. Combining the geochemical and moraine evidence indicates the presence of glaciers, the earliest ones yet discovered on Earth.

Biogeochemistry

The researchers think there might be a few causes for where the glaciers are.

According to Hofmann, it is possible that this region was close to the poles. Another theory holds that the entire globe experienced a "snowball Earth" period, in which low atmospheric CO2 and CH4 concentrations resulted in a "reverse greenhouse effect," which caused much of the earth to freeze. This may have occurred a few times in the recent past, according to scientists, which some experts believe could be the world's first recorded cooling period.

He claimed that slightly newer rocks sitting atop the rocks they analyzed contain the greatest sedimentary gold resources in the world. The creation of those gold deposits may have been facilitated by a transition from icehouse to greenhouse temperatures, but this has to be proven and requires additional research.

According to Dr. Andrey Bekker, an associate professor in the Department of Earth & Planetary Sciences at the University of California, the sedimentological evidence for this age's glaciation has been the subject of intense discussion and debate for decades.

Theories for this glaciation have ranged from high-altitude glaciation to glaciation in high latitudes. Analysis of the triple oxygen isotopes adds a completely new line of support to this claim. These findings are expected to inspire further research on the momentary oxygenation at that period because the biogeochemical carbon cycle not only regulates climate but also the amount of oxygen in the atmosphere, Interesting Engineering reports.

Ancient Glaciers in the World

Due to the dynamic motion of a valley glacier in Alaska, it can propel freshly formed ice along its entire span in under a century. According to flow rates, the 140+ mile-long Bering Glacier, Alaska's largest and longest glacier, can be traversed by ice in fewer than 400 years.

The oldest glacier found in Antarctica may have formed up to a million years ago, while that in Greenland surpasses the age of 100,000 years. In Alaska, experts were able to retrieve glacier samples that have been dated back approximately 30,000 years, according to USGS data.