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 New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>