Geologists from the University of Otago examined sediment data in an ice core recovered from the Ross Sea in
Prior to this study, it was believed that duringLast million years, the ice sheets of Antarctica expanded and retreated every 100 thousand years, which corresponded to the general climate changes on the planet, scientists explain. By analyzing ice core data (a cylindrical sample obtained by drilling ice), geologists have shown that, in fact, the Antarctic glacier has moved forward and retreated every 41,000 years.
In their work, scientists used a 6.2 metera sample of a glacier from the Ross Sea, which was obtained for another project in 2003 and has long been archived in the United States. The researchers conducted a paleomagnetic core sample core. This study reconstructs changes in the Earth's magnetic field. The results of the analysis based on the change in the Earth's magnetic field over time showed that the obtained sample keeps the history of the last million years.
To understand how the glacier changed over time, scientists studied the composition of sedimentary rocks in different layers.
Icebergs that form on the shelfglacier contain sediments and rocks attached to their underside. When icebergs break off, they float out to sea and shed rocks and sediment as they melt. By figuring out how much of this debris is in the core over time, we can build a picture of changes in the size of the ice sheet.
Christian Oniser, author of the study from the University of Otago
Previous ideas about the frequency of glacialperiods were inaccurate because they were based on incomplete data, the scientists note. At the same time, reconstruction of previous changes will help to better understand what will happen to the Earth in the future, especially in the context of global warming.
Read more:
Does science exist in extreme conditions? We answer in numbers
The Yellowstone supervolcano turned out to be many times more dangerous than scientists thought
The egg was dropped from space: look what happened to it