Scientists discovered the Lost River in Antarctica 34 million years later

Scientists have discovered a river similar in size to the Rio Grande that once dominated West Antarctica, offering a rare glimpse of the continent’s landmass, which is now covered in ice.

The 900-mile-long waterway is thought to have flowed about 44 to 34 million years ago, shortly before enormous ice sheets began to form on the continent.

At the time, after the dinosaurs and long before human life, Antarctica had a mild climate and was likely home to giant penguins, noted study author Cornelia Spiegel of the University of Bremen in Germany. The discovery also suggests that West Antarctica was above sea level at the time.

“We found that before the glaciation of West Antarctica, it was dominated by a large river system, had a temperate climate (river surface water temperature in summer was around 19°C) and a swampy environment,” she said Newsweek via e-mail.

“The river probably meandered through a vast coastal plain with swampy marshes along the banks.”

An international team of scientists discovered this river after analyzing samples from sandstone rock beneath the Amundsen Sea Embayment, where the West Antarctic Ice Sheet meets the ocean. In this rock, which dates back to the Eocene – a geological period that lasted from about 56 million to 34 million years ago – they found evidence of sediments originating from the Transantarctic Mountains, suggesting that they were washed away by water all the way. ancient river.

The researchers also found traces of organic chemicals associated with freshwater bacteria, further supporting the presence of a large river delta in the region. It stretches between the Transantarctic Mountains and the West Antarctic Ice Sheet and drains into the Amundsen Sea, the journal article said. Scientific advances.

“Our study also shows that West Antarctica was mostly above sea level (today most of the rocks under the ice are below sea level), but at the same time it was quite flat. Because of this lack of topography, West Antarctica likely remained free of large glaciers, while the mountainous areas of eastern The Antarctic began to freeze about 34 million years ago,” Spiegel said.

Scientists hope the discovery of this river will help them better understand the history of Antarctica’s geography and how it became the frozen continent it is today.

“The great Antarctic glaciation began at the Eocene-Oligocene transition [when the planet is known to have undergone a period of intense cooling] 34 million years ago, marking one of the most significant climate transitions in Phanerozoic times [from 538.8 million years ago to the present]”, the researchers wrote.

They added that reconstructing Antarctic conditions prior to this transition “provides important boundary conditions for understanding the subsequent cooling and onset of glaciation with major implications for ice sheet modelling”.

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