Featured Research

from universities, journals, and other organizations

New Antarctic geological timeline aids future sea-level predictions

Date:
January 16, 2013
Source:
British Antarctic Survey
Summary:
Radiocarbon dates of tiny fossilized marine animals found in Antarctica's seabed sediments offer new clues about the recent rapid ice loss from the West Antarctic Ice Sheet and help scientists make better predictions about future sea-level rise. This region of the icy continent is thought to be vulnerable to regional climate warming and changes in ocean circulation.

R/V Polarstern in inner Pine Island Bay, West Antarctica.
Credit: Photo: Dr.-Ing. Mirko Scheinert

Radiocarbon dates of tiny fossilised marine animals found in Antarctica's seabed sediments offer new clues about the recent rapid ice loss from the West Antarctic Ice Sheet and help scientists make better predictions about future sea-level rise. This region of the icy continent is thought to be vulnerable to regional climate warming and changes in ocean circulation.

Related Articles


Reporting this month in the journal Geology a team of researchers from British Antarctic Survey (BAS), the Alfred Wegener Institute for Polar and Marine Research (AWI) and the University of Tromsψ presents a timeline for ice loss and glacier retreat in the Amundsen Sea region of West Antarctica. The team concludes that the rapid changes observed by satellites over the last 20 years at Pine Island and Thwaites glaciers may well be exceptional and are unlikely to have happened more than three or four times in the last 10,000 years.

This study is part of an urgent international effort by polar scientists to understand if the recent rapid changes are unusual in the geological past.

The team studied the average rate of glacial retreat since the end of the last Ice Age around 12,000 years ago. Their work centred on Pine Island and Thwaites glaciers, which drain ice from the West Antarctic Ice Sheet into Pine Island Bay.

Lead author Dr Claus-Dieter Hillenbrand from BAS says, "As snow and ice builds up on the vast Antarctic Ice Sheet, the ice flows from the centre of the continent through glaciers towards the sea where it often forms floating ice shelves and eventually breaks off as icebergs. The floating ice shelves hold back the ice on land. A critical issue for us is to understand how the 'grounding line' -- the position where the ice sitting on land (glaciers) begins to float (ice shelves) -- has retreated landward over time. Satellite data are available only for the last 20 years and show that since 1992 the Pine Island and Thwaites glaciers have experienced significant thinning (melting), flow acceleration and rapid landward retreat of their grounding lines, with that of Pine Island Glacier having retreated up to 25 km. It's possible that the grounding lines may retreat even further inland over coming decades. Our study has revealed that episodes of fast glacier retreat similar to that observed over recent decades can only have occurred very rarely during the previous 10,000 years."

The investigation was carried out in 2010 during an expedition on-board the German research ship RV Polarstern. The science team used gravity corers up to ten metres long to extract mud from the sea floor of the continental shelf in the Amundsen Sea.

Co-author Dr Gerhard Kuhn from AWI explains, "It was important to get a better understanding of the rapid retreat that we see in the satellite data. As coring targets we selected three relatively shallow undersea ridges that lie within 110 kilometres of the current grounding line and flank a deep glacial valley which was carved into the sea bed by the glaciers during past ice sheet advances. These locations gave us the best chance to collect the tiny skeletons and shells of animals made of calcium carbonate. Such 'calcareous' microfossils are critical for using the radiocarbon technique to determine the age of the sediments, but they are normally extremely rare on the Antarctic continental shelf."

Co-author Dr James Smith, also from BAS, adds, "First we determined the distance between the core locations and the modern position of the grounding line. Then by dating the type of sediment material deposited at a core site in the open ocean (after the grounding line had moved further landward), we were able to calculate the average rate of glacier retreat over time."

This new research will be used to improve the accuracy of computer models that are essential to predict future ice loss in the Amundsen Sea sector of the West Antarctic Ice Sheet and its likely contribution to global sea-level rise. Over the last two decades the melting of West Antarctic glaciers has contributed significantly to sea-level rise (recent studies have suggested that continued melting would raise global sea level by up to 0.3 mm a year).

Some of the radiocarbon dating work was undertaken at the Natural Environment Research Council Radiocarbon Facility (Environment). The research was funded by the Natural Environment Research Council (NERC) and the Alfred Wegener Institute (AWI).


Story Source:

The above story is based on materials provided by British Antarctic Survey. Note: Materials may be edited for content and length.


Journal Reference:

  1. C.-D. Hillenbrand, G. Kuhn, J. A. Smith, K. Gohl, A. G. C. Graham, R. D. Larter, J. P. Klages, R. Downey, S. G. Moreton, M. Forwick, D. G. Vaughan. Grounding-line retreat of the West Antarctic Ice Sheet from inner Pine Island Bay. Geology, 2012; 41 (1): 35 DOI: 10.1130/G33469.1

Cite This Page:

British Antarctic Survey. "New Antarctic geological timeline aids future sea-level predictions." ScienceDaily. ScienceDaily, 16 January 2013. <www.sciencedaily.com/releases/2013/01/130116111737.htm>.
British Antarctic Survey. (2013, January 16). New Antarctic geological timeline aids future sea-level predictions. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2013/01/130116111737.htm
British Antarctic Survey. "New Antarctic geological timeline aids future sea-level predictions." ScienceDaily. www.sciencedaily.com/releases/2013/01/130116111737.htm (accessed October 31, 2014).

Share This



More Earth & Climate News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How A Chorus Led Scientists To A New Frog Species

How A Chorus Led Scientists To A New Frog Species

Newsy (Oct. 30, 2014) — A frog noticed by a conservationist on New York's Staten Island has been confirmed as a new species after extensive study and genetic testing. Video provided by Newsy
Powered by NewsLook.com
Raw: Hawaii Lava Approaching Village Road

Raw: Hawaii Lava Approaching Village Road

AP (Oct. 30, 2014) — The lava flow on the Big Island of Hawaii was 225 yards from Pahoa Village Road on Wednesday night. The lava is slowing down but still approaching the village. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Endangered Carpathian Ponies Are Making a Comeback in Poland

Endangered Carpathian Ponies Are Making a Comeback in Poland

AFP (Oct. 29, 2014) — At the foot of the rugged Carpathian mountains near the Polish-Ukrainian border, ranchers and scientists are trying to protect the Carpathian pony, known as the Hucul in Polish. Duration: 02:17 Video provided by AFP
Powered by NewsLook.com
Deadly Mudslide in Sri Lanka Buries Houses

Deadly Mudslide in Sri Lanka Buries Houses

AP (Oct. 29, 2014) — A mudslide triggered by monsoon rains buried scores of workers' houses at a tea plantation in central Sri Lanka on Wednesday, killing at least 10 people and leaving more than 250 missing, an official said. (Oct. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins