Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hitchhiking rocks provide details of glacial melting in West Antarctic

03.01.2003


Rocks deposited by glaciers on mountain ranges in West Antarctica have given scientists the most direct evidence yet that parts of the ice sheet are on a long-term, natural trajectory of melting.



The West Antarctic Ice Sheet has been melting and contributing water continuously to the ocean for the last 10,000 years and is likely to keep doing so, says John Stone, University of Washington associate professor of Earth and space sciences.

Measuring and understanding changes in the Earth’s ice sheets over the past few decades, and predicting their future behavior are major challenges of modern glaciology. But it is important to view these changes in the context of what’s been happening naturally over centuries and millennia. This work establishes a background pattern of steady decline in the West Antarctic ice sheet, Stone says. If melting continues at the same pace in future, the West Antarctic Ice Sheet – about 360,000 square miles, or about the size of Texas and Colorado combined – would melt away in another 7,000 years.


It is still unknown if that process is being speeded by human-caused warming of the oceans and atmosphere, Stone says, but because much of the bedrock beneath the ice is below sea level, the ice sheet could be particularly susceptible to any future thinning and warming of the oceans around its edges.

The ice sheet contains enough water to raise global sea level by about 5 meters, or 16 to 17 feet, but says Stone, lead author of a paper in the Jan. 3 issue of the journal Science. "A rapid melting event that released even a small faction of this amount could have disastrous consequences for coastal regions".

Previous research inferred the history of the ice sheet indirectly, from such things as changing beach levels or volcanic debris. In this study, the scientists gathered rocks deposited by glaciers on mountain peaks and dated them using a new technique that allowed them to track the thinning of the ice sheet over the last few thousand years. The scientists believe they have documented the retreating margins of the ice like never before.

A research grant and logistic support from the National Science Foundation made it possible for researchers to visit seven peaks in the Ford Ranges, a series of mountain ranges near the Ross Sea. The Ford Ranges are one of only a handful of places in West Antarctica where mountains protrude through the ice sheet.

Even the peaks of the Ford Ranges – some that now jut nearly half a mile above the ice surface – were buried by ice 10,000 years ago, only emerging after glaciers scraped down their flanks. In the process, the glaciers left behind time capsules of a sort: rocks ranging in size from bricks to boulders that hitched rides inside glaciers until the ice melted away, leaving the rocks stranded high and dry on the mountainsides.

As the covering layer of ice thinned and disappeared, the rocks were exposed to bombardment by cosmic rays, altering their isotopic makeup. Using a particle accelerator to count the cosmic ray-produced atoms in a rock allows scientists to determine its age and, as a result, the time the glacier and rock parted ways.

"In all cases we got very tight, consistent correlations of age with altitude, so we are able to track the margins of the ice sheet coming down the mountain sides with this approach," Stone says. The most surprising aspect is how recently the ice has thinned in West Antarctica. Ice sheets which once covered huge areas of North America and Europe had all but disappeared by 10,000 years ago. Deglaciation in West Antarctica had only just begun by that time. Hundreds of meters of ice have since disappeared, under climatic conditions very similar to the present day.

"The Ice Age never really came to an end in that part of the world," Stone says.


Co-authors on the Science paper are Gregory Balco and Seth Cowdery, University of Washington graduate students in earth and space sciences (Cowdery was an undergraduate at Colorado College when the work was done); David Sugden, professor of geography, University of Edinburgh, Scotland; Marc Caffee, associate professor of physics, Purdue University (he was with Lawrence Livermore National Laboratory when the work was done); Louis Sass, National Outdoor Leadership School (an undergraduate student at Colorado College when the work was done) and Christine Siddoway, professor of geology, Colorado College.


Sandra Hines | EurekAlert!
Further information:
http://www.washington.edu/

More articles from Earth Sciences:

nachricht The Wadden Sea and the Elbe Studied with Zeppelin, Drones and Research Ships
19.09.2017 | Helmholtz-Zentrum Geesthacht - Zentrum für Material- und Küstenforschung

nachricht FotoQuest GO: Citizen science campaign targets land-use change in Austria
19.09.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

Im Focus: Artificial Enzymes for Hydrogen Conversion

Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.

Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

New quantum phenomena in graphene superlattices

19.09.2017 | Physics and Astronomy

A simple additive to improve film quality

19.09.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>