14 DAY TRIAL // Investigators with the Antarctic Geologic Drilling Program (ANDRILL) say that their latest study conducted in Antarctica reveals a period of warming to have taken place on the Southern Continent about 15.7 million years ago.
The event did not last for very long, only a few thousand years, the team explains. In geological terms, that is an extremely brief period. This accounts for why very few signs of its presence were left behind.
The first drilling samples to hint at this period of warming were discovered in 2010 by Louisiana State University assistant professor of geology and geophysics Sophie Warny. Since then, the same place where the original samples were located provided a lot more study material.
Undoubtedly, the most remarkable thing about the samples was that they contained vast amounts of microfossils, in a concentration that researchers had never witnessed before. These were analyzed at the Florida State University (FSU) Antarctic Research Facility, in Tallahassee.
“First I thought it was a mistake, that it was a sample from another location, not Antarctica, because of the unusual abundance in microscopic fossil cysts of marine algae called dinoflagellates. But it turned out not to be a mistake, it was just an amazingly rich layer,” Warny explains.
“The two scientists in charge of the drilling, David Harwood of University of Nebraska – Lincoln, and Fabio Florindo of Italy, were equally excited. They had noticed that this thin layer had a unique consistency that had been characterized by their team as a diatomite, which is a layer extremely rich in fossils of another algae called diatoms,” she adds.
An extremely rich fossil content was discovered in a drill column that was about 1,107 meters (3,631 feet) in length. A 2-meter (6.5-foot) section of this sample column exhibited signs that it had formed under much warmer conditions than available on Antarctica.
However, that would have been impossible, since ices first appeared on the Southern Continent about 35 million years ago. The development of woody plants and dinoflagellate algae is hampered by cold weather, so discovering fossils belonging to these lifeforms could only mean that a warming period occurred, Daily Galaxy reports.
“We all analyzed the new samples and saw a 2,000 fold increase in two species of fossil dinoflagellate cysts, a five-fold increase in freshwater algae and up to an 80-fold increase in terrestrial pollen,” Warny explains.
“Together, these shifts in the microfossil assemblages represent a relatively short period of time during which Antarctica became abruptly much warmer,” she concludes.