Arctic ice shelf might have broken up before
October 26th, 2011 - 7:28 pm ICT by IANSLondon, Oct 26 (IANS) Researchers think a Canadian ice shelf had broken up 1,400 years ago, long before industrialisation impacted the planet.
A study of sedimentary material on the bottom of Disraeli Fjord in Canada turned up proof of what the team from Universite Laval in Canada described as a major fracturing event 1,400 years ago.
They believe at least an ice shelf, Ward Hunt north of Ellesmere Island, Nunavut, Canada, the largest remaining ice shelf in the Arctic at 170 square miles, broke up and then re-froze 800 years ago, the journal Proceedings of the National Academy of Sciences reports.
Ice shelves are thick ice crusts which have been pushed out to sea by the pressure from glaciers. They act as dams in fjords and result in sediment building up at the boundary between fresh water from the ice and salt water from the ocean, according to the Daily Mail.
Researchers used carbon dating and other techniques to examine the sediment and were able to create a timeline of events.
They found the ice shelf appeared 4,000 years ago staying whole for several thousand years before fracturing 1,400 years ago. They said it didn’t fully re-freeze until 800 years ago. It began to shrink again almost 100 years ago and is getting smaller every year.
Dermot Antoniadesa from Universite Laval said: “At this point, it doesn’t appear that the shelf ice around Ellesmere Island is any smaller now than it was during the previous period of warming, but because it’s still shrinking, it’s possible it could become, an unprecedented event.”
Ice shelves in the Arctic lost more than 90 percent of their total surface area during the 20th century and are continuing to disintegrate rapidly.
- Ancient fossils hold clues for predicting future climate change - Apr 09, 2011
- Thickest Arctic Sea ice melting much faster - Mar 01, 2012
- How heat is transported to Greenland glaciers - Mar 29, 2011
- Satellite records Antarctica ice shelf's retreat - Apr 08, 2012
- Some Antarctic ice is building up from bottom - Mar 04, 2011
- Mummified forest in Canada yields climate clues - Dec 16, 2010
- Massive pieces of Canadas northern ice shelf floating free in the Arctic Ocean - Sep 03, 2008
- Arctic sea ice to melt by 2015: Expert - Nov 10, 2011
- Arctic Sea could become iceless by century-end - Oct 12, 2011
- NASA: Arctic's thickest ice diminishing faster than thin ice - Mar 01, 2012
- Arctic ice at lowest point in recent geologic history - Jun 03, 2010
- Arctic sea ice hits second-lowest level - Oct 05, 2011
- Arctic sea ice level reaches second-lowest in history - Oct 06, 2011
- Evidence of sea ice extending to equator 715 mln yrs ago hints at "snowball Earth" - Mar 05, 2010
- Antarctic Ice Shelf collapse possibly triggered by ocean waves - Feb 12, 2010
Tags: arctic ice, canadian ice shelf, daily mail, dams, ellesmere island, fjord, fjords, glaciers, island nunavut canada, journal proceedings, national academy of sciences, proceedings of the national academy, proceedings of the national academy of sciences, salt water, sediment, sedimentary material, several thousand, shelf ice, thick ice, unprecedented event