Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Thawing ice makes the Alps grow

10.11.2016

The Alps are steadily "growing" by about one to two millimeters per year. Likewise, the formerly glaciated subcontinents of North America and Scandinavia are also undergoing constant upward movement.

This is due to the fact that at the end of the Last Glacial Maximum (LGM) about 18,000 years ago the glaciers melted and with this the former heavy pressure on the Earth's surface diminished.


This is a 3-D ice-model of the Alps during Last Glacial Maximum.

Figure: University of Potsdam, background model based on ESRI Germany data

The ice reacted rapidly to climate change at that time whereas the Earth's crust is still responding today to this relatively sudden melting of ice. During the LGM the Alps were also coated with an ice cap that temporarily reached far into the alpine foreland. The extent of glaciation was much smaller here than on the subcontinents of North America and Scandinavia.

This is why it was assumed for a long time that the retreat of the ice cap back then did not play a significant role in the steady uplifting of the Alps today. However, an international team with the participation of the GFZ scientists Dirk Scherler and Taylor Schildgen have now been able to show that the loss of the LGM ice cap still accounts for 90 percent of today's uplifting of the Alps.

Vertical motions of the Earth's crust are mainly caused by tectonic deformation due to movements of tectonic plates, and by volcanism, and unloading of water, ice, and sediments. The movement of the crust can be measured by geodetic methods via satellites and ground stations.

For old, tectonically stable continents like the subcontinents of North America and Scandinavia it has been known for a long time that vertical motion is almost exclusively caused by the so called postglacial "rebound effect" - i.e. the upward motion of the crust due to the thawing of the glaciers. In young mountain belts such as the Alps, however, complex mechanisms come into play that mutually effect each other:

The African Plate subducts below the Eurasian Plate, and the Adriatic Plate -- a sub-plate of the African Plate -- moves counterclockwise below the Eurasian Plate. Furthermore, as in Scandinavia and North America, there is unloading due to erosion and sediment transport, and "deglaciation". The causes for today's uplift of the Alps has been a matter of debate for over a quarter of a century.

For a long time it was assumed that the uplift is primarily caused by erosion and sediment transport, mainly by rivers, towards the foreland. The new study compares by how much erosion, ice unloading, and local tectonics contribute to the vertical motion of the Alps. The scientists use models supported with drill core data to show that the better part of postglacially, and therewith after the end of the main glacial phase, eroded material was deposited within the orogen.

Hence, this process can be excluded as a main cause for the alpine uplift. The models, however, show that, just like in Scandinavia and America, the uplift-signal is best explained with a relieving compensatory movement after the decline of the LGM-glaciers: Within only 3,000 years the glaciation of the Alps decreased by about 80 percent. Only about 10 percent of today's uplift can be attributed to sediment unloading. Locally, especially in parts of Austria, tectonic effects add to the uplift, likely caused by the circular motion of the Adriatic sub-plate. With their models the scientists are able to show that the glacial load weighed about 62,000 gigatonnes, while the postglacial sedimentary unloading only accounts for about 4,000 gigatonnes.

###

Original study: Jürgen Mey, Dirk Scherler, Andrew D. Wickert, David L. Egholm, Magdala Tesauro, Taylor F. Schildgen, Manfred R. Strecker. Glacial isostatic uplift of the European Alps. Nature Communications 7:13382. DOI: 10.1038/ncomms13382

Media Contact

Josef Zens
josef.zens@gfz-potsdam.de
49-331-288-1040

 @GFZ_Potsdam

http://www.gfz-potsdam.de 

Josef Zens | EurekAlert!

Further reports about: Alps GFZ Glacial Last Glacial Maximum mountain belts sediment transport water ice

More articles from Earth Sciences:

nachricht Geophysicists and atmospheric scientists partner to track typhoons' seismic footprints
16.02.2018 | Princeton University

nachricht NASA finds strongest storms in weakening Tropical Cyclone Sanba
15.02.2018 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>