Experts know that Antarctica began to be engulfed by ices some 35 million year ago, but thus far they had no idea how the continent evolved afterwards. In a new study, a team of experts highlights how vegetation was eventually removed from the South Pole. Measurements conducted on fossilized pollen grains collected from the Antarctic continental shelf indicate that the final forms of vegetation to endure on the massive continent disappeared around 12 million years ago.
This analysis was conducted on the first direct and detailed climate record ever to be found. It determined that vegetation endured as tundra for millions of years after ices began covering the land.
Tundra now exists near the North Pole and surround Arctic regions. The same type of landscape managed to endure on the northern peninsula of Antarctica, but temperatures eventually got very low, and ices advanced to smother everything in their path.
Experts at the
Rice University and the Louisiana State University (LSU) will publish details of their work in the July 12 print issue of the journal Proceedings of the National Academy of Sciences.
“The best way to predict future changes in the behavior of Antarctic ice sheets and their influence on climate is to understand their past,” lead author John Anderson explains. He holds an appointment as a marine geologist at Rice.
Such studies of Antarctica became possible due to the fact that the continent is warming up. Over the past few decades, average temperatures have increased substantially, and led to the collapse of important ice sheets.
Glaciers on the Antarctic Peninsula are also declining continuously, experts add. Mean annual temperatures in this area increase as much as six times faster than mean annual temperatures do at a global level.
“There's a longstanding debate about how rapidly glaciation progressed in Antarctica,” LSU geologist Sophie Warny explains. Also part of the LSU team were colleague Rosemary Askin and a number of students.
“We found that the fossil record was unambiguous; glacial expansion in the Antarctic Peninsula was a long, gradual process that was influenced by atmospheric, tectonic and oceanographic changes,” she adds.
“The pollen record in the sedimentary layers was beautiful, both in its richness and depth. It allowed us to construct a detailed picture of the rapid decline of the forests during the late Eocene and the widespread glaciation that took place in the middle Miocene – about 13 million years ago,” Warny concludes.
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