The World’s Oldest Glacier: Hidden Under African Goldfields

KOMPAS.com – Scientists have discovered the world’s oldest large iceberg or glacier. Uniquely, this glacier lies hidden under a gold field in the badlands of South Africa.

In fact, according to research, the age of ice deposits on the African continent is much older than the glaciers in Antarctica, which are inhabited by snow.

Quoted from the website of the United States Geological Survey (USGS), the oldest ice glaciers in Antarctica are likely to be close to 1 million years old.

Meanwhile, ancient glaciers in Africa are estimated to be 2.9 billion years old, as reported in the journal Geochemical Perspectives Letters published on June 13, 2023.

During the study, scientists excavated sedimentary rock and analyzed core samples from a field located in South Africa.

The location is part of the Pongola Supergroup, a succession (change in components) of volcanic and sedimentary rocks that formed during the Mesoarchean era, around 3.2 billion to 2.8 billion years ago.

“We found very well preserved glacial deposits near a South African gold field,” said Ilya Bindeman, University of Oregon Professor of Geochemistry and Volcanology, Isotope Geochemistry and Volcanology, quoted from Live Science, Saturday (22/7/2023).

“This is one of the few areas that has remained intact and unchanged since Earth’s beginning,” he continued.

Also read: Scientists Find the Sunniest Place on Earth, Like Standing on the Surface of Venus

The world’s oldest glacier in the African goldfields

In fact, in the past, other researchers have found some physical samples that suggest ancient liquefaction occurred in this region.

However, evidence of glaciation or freezing over billions of years ago is still debated.

In order to investigate, the scientists also collected sedimentary rock samples in the Kaapvaal Craton area, ancient rocks located in the southeastern region of South Africa.

The rock also contains deposits from the Pongola Supergroup.

Not only collecting, the team also analyzed core samples from the same area donated by the AngloGold-Ashanti mining company.

After examining the samples, the researchers found the world’s oldest known glacial moraine, which is basically debris left by glaciers that gradually melted and shrank.

The presence of this glacial material can also provide clues about Earth’s climate and geography during that time period.

One of the theories, as reported by IFL Science, Thursday (13/7/2023), is that the South African region was probably close to one of the poles 2.9 billion years ago.

“Another possibility is that the entire Earth is in a ‘snowball’ period, in which low atmospheric concentrations cause the ‘reversed greenhouse effect’ and trigger large portions of the planet to freeze over,” said another study author, Axel Hofmann.

“If so, this would be the earliest period of global cooling that has been recorded,” said Professor of the Department of Geology at the University of Johannesburg, South Africa.

Also read: This Is What Would Happen if the Doomsday Glacier in Antarctica Collapsed

Need further research

To determine Earth’s climatic conditions at the time the sediments formed, scientists used a technique called three-oxygen isotope analysis.

“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,” Bindeman said.

According to him, the team found that the rock has a very low amount of 18O and a very high amount of 17O, which indicates it was formed at cold temperatures.

The use of triple oxygen isotope analysis may also add new avenues for finding evidence of early Earth glaciation.

On the other hand, Professor of Geology University of California, Andrey Bekker, who was not involved in the study said, more research needs to be done to really understand Earth’s climate billions of years ago.

“It’s incremental progress toward sort of understanding early Earth’s environment, climate change in early Earth’s history, and so on,” he said.

Nevertheless, he added, humans do not yet know the extent of the cold climate in question.

“Is it just local or extends to low latitudes around the world,” he concluded.

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2023-07-23 06:00:00
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