Imagine a time machine that can take you back to the age of the dinosaurs. Suddenly, you find yourself in a thick, swampy forest, with insects buzzing among the flowers, ferns, and conifers.
Believe it or not, you are standing in West Antarctica.
Scientists from Germany and the UK have now found amber there for the first time – the reconstructed ‘blood’ of ancient coniferous trees that once grew on Earth’s southernmost continent between 83 and 92 million years ago.
Along with fossils of roots, pollen, and grains, amber provides excellent evidence that a mid-Cretaceous, swampy rainforest existed near the South Pole, and that this prehistoric area was “dominated by conifers”, similar to the forests of New Zealand and Patagonia. today.
Amber excavations in Antarctica are pulling back the continent’s icy exterior to reveal an ancient habitat that was warm and wet enough to support amber-producing trees. By the middle of the Cretaceous, those trees would have had to survive during the months of extreme darkness during the winter.
But they survived, apparently they survived. Even if they had to sleep for a long time.
Before this discovery, scientists had only found deposits of Cretaceous amber as far south as the Otway Basin in Australia and the Tupuangi Formation in New Zealand.
“It was very interesting to note that, at some point in their history, all seven continents had a climate that allowed resin-producing trees to survive,” said marine geologist Johann Klages of the Alfred Wegener Institute in Germany.
“Our goal now is to learn more about the nature of the forest – if it is fresh, if we can find traces of life embedded in the resin. This discovery allows a journey into the past in a more direct way.”
Scientists have found fossils of wood and leaves in Antarctica since the beginning of the 19th century, but most of these finds are from hundreds of millions of years ago when there was a large area south of Gondwana. As Antarctica drifts south from Australia and South America, it is unclear what is happening to its forests.
In 2017, researchers drilled into the ocean floor near West Antarctica and pulled up well-preserved evidence of these long-lost sites.
After several years of analysis, Klages and a team of researchers announced in 2020 that they had discovered a database of roots dating back to the mid-Cretaceous. Under the microscope, they also identify evidence of pollen and spores.
Similar drilling has now provided concrete evidence that resin-producing trees once existed in Antarctica.
In a 3-meter (10-foot) long layer of mudstone, Klagen and the new team described several pieces of translucent amber, just 0.5 to 1.0 millimeters in size. Each one hosts a variation of yellow to orange colors with a regular scalloped top break.
This is a sign of resin flow, which occurs when sap oozes from the tree to seal the bark from fire or insect damage.
The Cretaceous was one of the warmest periods in Earth’s history, and volcanoes found in Antarctica and nearby islands show evidence of frequent forest fires during this time.
The resin was probably preserved and fossilized because high water levels quickly sealed the tree’s resin, protecting it from ultraviolet rays and oxidation.
It appears that the resin contains tree bark, but further analysis is needed to confirm that.
Piece by piece, scientists are slowly piecing together a picture of what Antarctica’s forests once looked like and how they functioned 90 million years ago.
The study was published in Antarctic research.
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