They discovered a huge river dating back 40 million years in Antarctica

A group of researchers has found a lost ancient world beneath the deep ice of Antarctica. The thing is There was a giant river meandering through there about 40 million years ago.Specifically, as has been said, Life SciencesGeologists drilling into the vast ice sheet in West Antarctica have discovered the remains of an ancient river system that at its peak stretched some 1,500 kilometers (620 miles). The findings were published June 5 in the journal Sciences.

The Antarctic River has existed for about 40 million years, and its course is estimated to extend 1,500 kilometres to the Amundsen Sea. In times even before this mighty river existed, several sectors of present-day West Antarctica were composed of temperate tropical forests.

“This is a very interesting finding,” said team member Johann Klages, a sedimentologist at the Helmholtz Centre for Polar and Marine Research at the Alfred Wegener Institute in Germany.If we think about possible severe climate change in the future, we need to learn from periods of Earth’s history in which this has already happenedThe answers lie in the history of the planet itself.

Between 34 and 44 million years ago, in the geological epoch known as the Late Middle Eocene, Earth’s atmosphere changed radically. At that time carbon dioxide levels dropped dramatically and the atmosphere lost much of its ability to maintain higher temperatures. So, Global cooling caused glaciers to form on ice-free land.

Knowing the past to predict the future

Scientists are now interested in understanding how this major climate event evolved. In Antarctica, especially as carbon dioxide levels on Earth continue to rise due to human-caused climate change.

The amount of carbon dioxide during the late Eocene was roughly twice what it is today.. However, they could be similar to levels expected in about 150 to 200 years if greenhouse gas levels continue to rise.

Being able to obtain the material needed to investigate and reach these results is a scientific challenge. Today, most of West Antarctica is covered in iceThis makes it difficult to access the sedimentary rocks needed to study early environments. For this reason, geologists often rely on the types of grains, minerals, and fossils trapped in these sediments to determine what conditions characterize an area.

The work began in 2017, when Klages and other scientists who made up the research team set sail from Chile on the Polarstern, the largest scientific research vessel ever built. They had to cross the rugged Drake Passage and the western part of Antarctica. Equipped with advanced seafloor drilling equipment, He began collecting samples of soft sediment and hard rock from the frozen sea floor..

covered in miles of ice

Scientists were able to drill approximately 30 meters into the sea floor and recover sediments in layers from two different periods. By calculating the half-lives of radioactive elements, such as the percentage of uranium and lead in the sediments, they discovered that the bottom of the sediments formed during the middle Cretaceous period, about 85 million years ago. These deposits contain fossils, spores, and pollen characteristic of the temperate tropical forests that existed at that time..

On the other hand, the upper part of the deposit contained mainly sand of late Middle Eocene age, between 30 and 40 million years ago. After examining the material in detail, they identified a strong stratigraphic pattern in the Eocene sand layer They were similar to those coming from river deltas, very similar to those found in rivers such as the Mississippi, the Rio de la Plata or the Amazon..

A lipid biomarker analysis was performed, where they measured the amount of fats and sugars present in the sediment, and found It is a unique molecule commonly found in freshwater cyanobacteria.

The discovery confirmed their suspicions that an ancient river had meandered across the continent millions of years ago. The researchers traced the Eocene grains to a distinct salty region in the Trans-Antarctic Mountains, where they traversed a region extending about 1,500 kilometers before emptying into the present-day Amundsen Sea.

News Reference:
Maximilian Zundel et al. Across a vast transcontinental river system west of Antarctica during the Eocene..Science Fiction.10, eadn6056 (2024).DOI:10.1126/sciadv.adn6056.