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 In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

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...

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

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

Hope to discover sure signs of life on Mars? New research says look for the element vanadium

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>