Washington, Dec 31 (ANI): In a new study, which involved analyses of deposits of pollen grains, it has been determined that Sweden may have been virtually free of ice for long periods during the latest ice age, which suggests that the glaciation might have started some 20,000 years later than was previously assumed.
The study is part of a new doctoral dissertation at Stockholm University in Sweden.
According to Martina Hattestrand, a doctoral candidate at the Department of Physical Geography and Quaternary Geology, Stockholm University, "It's important that we get to the bottom of when the great ice sheets covered Sweden and how warm it might have been when there was no ice."
In order to understand the climate system of the earth, researchers today are studying the climatic variations of ice ages.
Since the most land forms and geological traces have been preserved from the latest ice age, much of the research focuses on that particular period.
An important aspect of the research is to study when the huge continental ice sheets grew and when they melted away, and to study the environment and climate of the areas that were free of ice.
The size and movement patterns of the ice sheets can be calculated by studying land forms and moraine deposits.
The ice-free periods can be studied by pollen analysis, among other methods.
Pollen analysis is a method in which scientists use pollen grains preserved in ancient sediment to create a picture of what plants once grew in the area and what the climate was like.
Martina Hattestrand's dissertation is based on studies of pollen grains that were deposited more than 40,000 years ago in small lakes during the ice-free phases of the latest glaciation.
During the warm phases of the Ice Age, high amounts of birch pollen were deposited, which indicates that summer temperatures were around 10 degrees centigrade in northern Sweden.
During cold ice-free phases, mostly grass and herbal pollen was deposited.
"The findings from my dissertation indicate that the first icing up phase of the latest Ice Age may in Scandinavia have started about 95,000 years ago - which is some 20,000 years later than was previously thought," said Hattestrand.
This indicates that Sweden may have largely been ice-free between 59,000 and 40,000 years ago.
If this is true, the last ice sheet of the Ice Age formed much more rapidly than was previously believed in order to have reached all the way down to northern Germany during the maximum phase about 22,000 years ago. (ANI)