A hidden river that has been hidden for 40 million years has been discovered in Antarctica.

Team geologists discovered an ancient river system under the ice sheet Antarctica West. This riverapproximately 1600 kilometers long, age will be between 34 and 44 million years.

Researchers University of Bremen and Alfred Wegener InstituteHelmholtz Center for Polar and Marine Research in Germanytogether with German, British, Irish and Swedish universities and research institutes, discovered the largest river system on the white continent and described it in a study published in the journal Science achievements.

Johann Klagessedimentologist researcher from the Alfred Wegener Institute in Germany and co-author of the study, noted that this discovery is a great achievement for understand extreme climate changes in Earth’s history. He explained that studying these periods can provide valuable information about the effects of global warming: “If we think about potentially severe climate change in the future, we need to learn from periods in Earth’s history where it has already happened.”

Klages’ team conducted an expedition to 2017 on board a research vessel Polar stern. They left southern tip of Chile towards West Antarctica and used modern drilling equipment to extract sediments. This analysis revealed layers from two different periods, the lower of which dates back to 85 million years ago (Middle chalk) and upper from 30 to 40 million years ago (Middle-Late Eocene).

A more detailed analysis of Eocene deposits showed layered pattern typical of a river delta, similar to the Mississippi River in North America. Availability biomarkers from cyanobacteria The fresh water in these sediments supported the hypothesis of an ancient river that once flowed across the Antarctic continent.

To map the topography of the hidden landscape, the team used ice-penetrating radar and sonar. They found a small buried island almost two kilometers away below the surface, with blocks of land separated by U-shaped valleys.

About 34 million years ago, Antarctica was ice-free but had a temperate climate, so Antarctica was not always an isolated landmass covered in ice, the researchers say. About 100 million years ago it formed the central part of a supercontinent. Gondwana

. After the breakup of Gondwana, Antarctica became an independent continent.

During Eocene average, between 34 and 44 million years ago, The level of carbon dioxide in the Earth’s atmosphere was almost twice as high as current, similar to forecasts for the next 150–200 years, if greenhouse gases continue to increase. Subsequently, global cooling at the end of the Eocene led to the formation of glaciers.

The team examined sediment samples obtained from Amundsen Sea off the coast of West Antarctica during an expedition Research icebreaker “Polarstern”. Their analysis shows that most of the minerals and rock fragments in these samples do not come from West Antarctica, but from the Transantarctic Mountains on the edge of East Antarctica, thousands of kilometers away.

This mountain range has risen since the late Eocene as a steep shelf of a continental rift. West Antarctic Rift Systemwhich today divides Antarctica into two landmasses: East and West Antarctica.

Since then, the uplift and erosion of the Transantarctic Mountains has created large amounts of eroded debris, which the newly discovered river has carried and deposited more than 1,500 kilometers across the West Antarctic Rift System into what is today the Amundsen Sea. them there, in the swampy river delta. Modern examples of large river systems in similar geological settings are the Rio Grande River in the Rio Grande Rift or the Rhine River in the Upper Rhine Graben.

The existence of such a transcontinental river system shows that Unlike today, most of West Antarctica must have been located above sea level as vast, flat coastal plains.. Due to its low topography, West Antarctica was still ice-free in the late Eocene, while the mountainous regions of East Antarctica had already begun to become covered with ice.

This discovery not only sheds light on the geological past of the Earth, but also gives important data for predicting how the East Antarctic ice sheet may respond to rising CO2 levels in the future.