New Zealand (Commonwealth Union) – The findings of studies on the ice age were initially put forward by geologist Jean de Charpentier who began studying the glaciers in 1818 after a natural disaster. Geologist Louis Agassiz who studied the work of Jean de Charpentier put forward a hypothesis on the ice age. A chance discovery of an unexplored Antarctic sediment core brought about University of Otago researchers to flip our knowledge of how often ice ages occurred in Antarctica.
Lead author Dr Christian Ohneiser, of the Department of Geology, indicates that they were much more frequent than assumed on prior occasions, he further stated that until this research, it was generally known that in the past million years global ice volume, including Antarctica’s ice sheets, stretched further and retreated every 100,000 years, but this research indicates it may have happened every 41,000 years.
The study came in following Dr Ohneiser sampling a sediment core from the Ross Sea for another project put together to reconstruct the retreat of the Ross Ice Shelf following the last ice age.
“The 6.2 metre core was recovered in 2003 and placed in an archive in the US, but was not studied further. I sampled it because I was expecting the core to have a record spanning the last 10,000 or so years,” said Dr Ohneiser. “I conducted a paleomagnetic analysis on the core, which reconstructs changes in the earth’s magnetic field, and found a magnetic reversal showing it was much older and had a record spanning more than 1 million years.”
Sedimentary and magnetic mineral indicators paved the way for Dr Ohneiser to reconstruct how large the Ross Ice Shelf, and the West Antarctic Ice Sheet which feeds the shelf, as they existed. He indicated that the study demonstrates the way New Zealand is punching above its weight in terms of Antarctic studies.
