An international team of researchers took a 90 million-year-old soil sample that has lifted the veil of mystery over ancient Antarctica. It turns out that once there were cool humid tropics with dense vegetation, rivers and swamps. The average annual air temperature hovered around 12 ° C, in summer it rose to a pleasant 19 ° C, and the amount of precipitation could be compared to northern Europe.
Researchers made this startling discovery by studying soil deposits with computed tomography at a depth of 27-30 m below the ocean floor, in the Amundsen Sea off the western coast of Antarctica. According to scientists, this layer at the height of the Cretaceous period was not formed in the ocean, but on land. The soil consisted of fine-grained silt and clay, with ubiquitous inclusions of pollen and plant spores, and the entire sample was penetrated by a network of tree roots.
“The plant cells found indicate that 85-90 million years ago, temperate rainforests grew here, similar to those that can still be found in, say, southern New Zealand, ” says Ulrich Salzmann, co-author of the study. According to calculations, the entire Antarctic continent was supposed to be covered with vegetation, ice sheets were completely absent.
It remains to be understood how such a mild climate could exist in the distant South? To achieve such average temperatures at that time in Antarctica, the concentration of carbon dioxide in the atmosphere had to be much higher than previously thought - not 1K: 1000K, but 1, 1K-1, 6K: 1000K particles.
Several new problems emerge from all the findings of the study. First, scientists will now have to revise the established Cretaceous climate models. And secondly, it raises a key question - what happened on a planetary scale that turned the flourishing continent into an icy desert.