Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mapping glaciers

09.10.2015

Geologists supported by the Swiss National Science Foundation have developed a new technique for mapping an entire glacier. They could confirm a theoretical model that describes how climate change affects erosion.

Supported by the Swiss National Science Foundation (SNSF), a team led by Frédéric Herman of the University of Lausanne has mapped the Franz Josef Glacier in New Zealand.


A helicopter takes researcher Mattia Brughelli up to the Franz Josef Glacier in New Zealand. © Benjamin Lehmann

The researchers have developed a new technique to study more precisely the relationships between global warming, glacier movement and erosion of rocks located below the ice mass.

“The glacier is over 10 kilometres in length and fairly similar to those found in Switzerland,” explains Frédéric Herman. “We selected it because of its location on a tectonic fault, with contrasting geological layers that contain graphite, an element that provides us with information on erosion.” The results of the study have been published in Science (*).

Probing the geological history

The researchers used a combination of two techniques to map the glacier. First, stereoscopic satellite imagery allowed them to estimate the speed of movement at the surface. They were then able to extrapolate the speed at which the lower layer is sliding over the bedrock (between 30 and 300 metres each year).

At the same time, the study sought to quantify the intensity of erosion below the glacier – the extent to which the glacier erodes the rock below it as it slides along. The research team took an indirect approach, as Frédéric Herman explains:

“We studied the crystalline structure of the graphite – carbon formed from fossilised organic matter – contained within the rock flour retrieved downstream of the glacier. It provides us with quite precise information on the conditions at the time the graphite was formed, in particular its temperature, which was between 300 and 700 degrees. When we compare this with samples taken from around the glacier, we can work out the origin of the flour. Since the quantity of flour is directly linked to the rate of erosion, it is possible to draw a map showing the intensity of erosion beneath the glacier.”

The researchers used the Raman spectroscopy technique to analyse the crystalline structure of the material. “Until now, geologists relied on isotope analysis, which requires very heavy equipment,” continues the researcher. “It could take years just to obtain forty samples. With our technique, our Master’s student Mattia Brughelli successfully analysed 4000 samples in two weeks, and then produced a very precise map of the glacier with a resolution of 1 metre.”

A theory validated

The measurements confirm a theoretical model that was proposed in 1979, predicting that erosion is not simply proportional to the speed of movement of the glacier, but is related to its square. “In the last few decades, we have been able to observe that glacier movement is accelerating,” says Frédéric Herman.

“Our model indicates that erosion will intensify in a non-linear fashion with global warming.” That means there will be increased sediment levels in alpine streams, which will increase the risk of debris flow, a mix of water and mud. “Our work shows that natural systems can be very perceptible to changes in the environment, even mountains.”

The study was realised in cooperation with the French National Museum of Natural History, the Californian Institute of Technology and the Institute of Geological and Nuclear Survey Science in New Zealand.

(*) F. Herman et al. (2015). Erosion by an Alpine glacier, Science, vol. 350, 6257, doi/10.1126/science.aab2386

Contact
Professor Frédéric Herman
Institute of Earth Surface Dynamics
University of Lausanne
1015 Lausanne
Tel: +41 (0)21 692 43 80 and +41 (0)79 608 32 98
E-mail: Frederic.Herman@unil.ch

Weitere Informationen:

http://www.snf.ch/en/researchinFocus/newsroom/Pages/news-151009-press-release-ma...

Kommunikation | idw - Informationsdienst Wissenschaft

More articles from Earth Sciences:

nachricht Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Predicting unpredictability: Information theory offers new way to read ice cores

07.12.2016 | Earth Sciences

Sea ice hit record lows in November

07.12.2016 | Earth Sciences

New material could lead to erasable and rewriteable optical chips

07.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>