Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How do Landslides control the weathering of rocks?

01.12.2015

Chemical weathering in mountains depends on the process of erosion.

Chemical weathering of rocks over geological time scales is an important control on the stability of the climate. This weathering is, in turn, highly dependent on the mechanical erosion processes in the river catchments where it occurs.


„Water flowing from the base of a landslide deposit, Gaunt Creek, Western Southern Alps of New Zealand “ (Foto: N. Hovius, GFZ)

Very high erosion rates in active mountain ranges, however, produce such large amounts of eroded rock and sediment that weathering cannot keep pace with erosion. This seemingly straightforward relationship is now put into question by a team of geoscientists from France and Germany.

In the Southern Alps of New Zealand, they found that landslides, despite only affecting a small part of the landscape, accelerate the weathering of the eroded material they create enormously. (current online edition, Nature Geoscience, 30.11.2015)

The researchers examined the relationship between landslides and their weathering impact with geochemical methods; they sampled a range of water sources from the study area, comparing leachate from the base of landslide deposits, streams from small catchments with no landsliding, and large rivers draining hundreds of square kilometres.

The study area in New Zealand is characterized by heavy rainfall and large earthquakes, which both act to generate bedrock landslides. The geoscientists discovered a strong correlation between the dissolved solutes in the sampled waters and the occurrence of landslides.

The ratio of Sodium to Calcium, for example, allowed clear distinction to be drawn between the sources, including distinguishing between water from landslides, deeper groundwater, or from hydrothermal springs.

“Over the whole range of scales, from a single hillslope to an entire mountain belt, the weathering of rocks is reflected in the pattern of the dissolved solutes of the surface water” explains Robert Emberson from the GFZ German Research Centre for Geosciences.

This systematic pattern is directly linked to the areas of landsclides.We find that systematic patterns in surface water chemistry are strongly associated with landslide occurrence at scales, “The impact on weathering from landslides that occurred even several decades ago is still clearly observed in the samples we collect today”, says GFZ scientist Emberson.

Although landslides and the mechanical erosion they cause, only affect small parts of the landscape at any given time, they create massive amounts of fresh mineral surfaces: every single piece of rock in the landslide deposit offers a surface where the water that seeps in can stimulate chemical processes.

Since the water does not run off at the surface but percolates slowly through the rock debris, it creates ideal conditions for rapid chemical weathering. Chemical weathering thus is controlled by landslides in active mountain belts.

The possible impact of this effect on the global climate remains to be investigated.
Robert Emberson, Niels Hovius, Albert Galy and Odin Marc: “Chemical weathering in active mountain belts controlled by stochastic bedrock landsliding”, Nature Geoscience, advance online publication, 30.11.2015, Doi: 10.1038/NEO2600

Dipl.Met. Franz Ossing | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
Further information:
http://www.gfz-potsdam.de/

More articles from Earth Sciences:

nachricht Strength of tectonic plates may explain shape of the Tibetan Plateau, study finds
25.07.2017 | University of Illinois at Urbana-Champaign

nachricht NASA flights gauge summer sea ice melt in the Arctic
25.07.2017 | 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: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA mission surfs through waves in space to understand space weather

25.07.2017 | Physics and Astronomy

Strength of tectonic plates may explain shape of the Tibetan Plateau, study finds

25.07.2017 | Earth Sciences

The dense vessel network regulates formation of thrombocytes in the bone marrow

25.07.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>