Imagine a time machine that could take you back to the age of dinosaurs. Suddenly you find yourself in a dense, swampy forest, with insects buzzing among the flowers, ferns and conifers.
Believe it or not, you are in West Antarctica.
German and British scientists discovered amber there for the first time – the fossilized “blood” of ancient conifers that once grew on Earth’s southernmost continent between 83 and 92 million years ago .
Along with root, pollen and spore fossils, the amber provides one of the best evidence to date for the existence of a Mid-Cretaceous swamp rainforest near the South Pole and that this prehistoric environment was “dominated by conifers”, similar to the forests of the South Pole. New Zealand and Patagonia today.
The discovery of amber in Antarctica rolls back the continent’s current icy exterior to reveal an ancient habitat once warm and humid enough to support resin-producing trees. By the mid-Cretaceous, these trees would have had to survive months of total darkness during winter.
But they clearly survived. Even if they had to remain dormant for long periods of time.
Before this discovery, scientists had only discovered Cretaceous amber deposits as far south as the Otway Basin in Australia and the Tupuangi Formation in New Zealand.
“It was very exciting to realize that at some point in their history, all seven continents had climatic conditions that allowed resin-producing trees to survive,” says marine geologist Johann Klages of the Alfred Wegener Institute in Germany.
“Our goal now is to learn more about the forest ecosystem – whether it burned, whether we can find traces of life embedded in the amber. This discovery allows a journey into the past in another, more direct.”
Scientists have discovered fossilized wood and leaves in Antarctica since the early 19th century, but many of these discoveries date back hundreds of millions of years, to when the southern supercontinent of Gondwana existed. As Antarctica moves away from Australia and South America toward the South Pole, it’s unclear what happened to its forests.
In 2017, researchers drilled into the seafloor near West Antarctica and discovered exceptionally well-preserved evidence of these long-lost habitats.
After several years of analysis, Klages and a team of researchers announced in 2020 that they had found a network of fossilized roots dating back to the mid-Cretaceous. Under the microscope, they also identified traces of pollen and spores.
This same drilling has now provided concrete proof that resin-producing trees once existed in Antarctica.
In a layer of mudstone 3 meters (10 feet) long, Klagen and a new team described several tiny slices of translucent amber, measuring just 0.5 to 1.0 millimeters. Each exhibits a yellow to orange color variation with typical scalloped fractures on the surface.
This is a sign of resin flow, which occurs when sap escapes from a tree to seal the bark against injury from fires or insects.
The Cretaceous was one of the hottest periods in Earth’s history, and volcanic deposits discovered in Antarctica and nearby islands provide evidence of frequent wildfires during this period.
Amber was likely preserved and fossilized because high water levels quickly covered the tree’s resin, protecting it from ultraviolet rays and oxidation.
It even appears that the amber contains tiny pieces of tree bark, but further analysis is needed to confirm this.
Little by little, scientists are gradually building a picture of what Antarctica’s forests once looked like and how they functioned 90 million years ago.
The study was published in Research in Antarctica.
