Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists rewrite laws of glacial erosion

14.08.2003


Glaciers, it turns out, aren’t so different from people – they can gain weight in their bottoms and be less active, scientists have discovered.



Glaciers, the heavyweights of landscape erosion, grow not just from snow accumulating on their surfaces but also from beneath by freezing of meltwater which can affect the rate at which they can erode, according to a team of scientists, including one from Michigan State University.

Their discovery, reported in a cover story in the Aug. 14 issue of the international science journal Nature, paints a new picture of how glaciers sculpture and erode the earth’s landscapes.


"Glaciers have a profound effect on the landscape, especially in mountainous regions, and this research allows us to understand how glaciers accomplish this," said Grahame Larson, a professor of geological sciences at MSU.

Larson was part of a team of scientists who made winter treks to Alaskan and Icelandic glaciers to understand how glaciers erode and transport sediment, research funded by the National Science Foundation and the Cold Regions Research and Engineering Laboratory in Hanover, N.H.

The researchers’ interest was sparked when they observed that fountains of meltwater rushing from some glacier margins spawned icy rims. They eventually were able to link this phenomenon of nature to the less lyrical but instantly identifiable event of creating ice when one pops open a can of very cold soda just pulled from an ice chest.

Larson explained that rapidly transferring ice-cold water from a high pressure environment – be it the inside of a can of soda or beneath a hulking glacier – to a lower pressure environment causes ice to form.

The soda-can effect gets a new name: glaciohydraulic supercooling. In the case of glaciers, this frazil ice forms when meltwater at the glacier bed rushes up a steeply rising slope. The new ice then clogs drainage ways at the glacier bed, dumping sediment, thus reducing the meltwater’s (and glacier’s) ability to erode. This action is called stabilizing feedback and results in the formation of a new dirty-ice layer along the glacier’s underbelly.

"This is new," Larson said. "We’re introducing laws of erosion for glaciers, and thus making it easier to understanding how glaciers subdue mountains."

Larson’s work at MSU helped to substantiate the theory of glaciohydraulic supercooling – he detected "bomb tritium," an isotope of hydrogen dispersed across the globe in the 1950s and early 1960s during nuclear testing, near the bed of some glaciers.

Under the old model of glacier building, tritium would be expected only near a glacier surface where snow slowly transforms to glacier ice. But Larson showed that tritium can also occur near the glacier’s base as the result of recent snowmelt refreezing due to glaciohydraulic supercooling.


In addition to Larson, the paper, "Stabilizing feedbacks in glacier-bed erosion," is authored by Richard Alley of Pennsylvania State University; Daniel Lawson of CRREL; Edward Evenson of Lehigh University in Bethlehem, Pa.; and Gregory Baker of the University of Buffalo.

Grahame Larson | EurekAlert!
Further information:
http://www.msu.edu/

More articles from Earth Sciences:

nachricht Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen

nachricht Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>