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 Water cooling for the Earth's crust
22.11.2017 | Helmholtz Centre for Ocean Research Kiel (GEOMAR)

nachricht Retreating permafrost coasts threaten the fragile Arctic environment
22.11.2017 | 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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>