Chemical weathering in active mountain belts controlled by stochastic bedrock landsliding

  • A link between chemical weathering and physical erosion exists at the catchment scale over a wide range of erosion rates(1,2). However, in mountain environments, where erosion rates are highest, weathering may be kinetically limited(3-5) and therefore decoupled from erosion. In active mountain belts, erosion is driven by bedrock landsliding(6) at rates that depend strongly on the occurrence of extreme rainfall or seismicity(7). Although landslides affect only a small proportion of the landscape, bedrock landsliding can promote the collection and slow percolation of surface runoff in highly fragmented rock debris and create favourable conditions for weathering. Here we show from analysis of surface water chemistry in the Southern Alps of New Zealand that weathering in bedrock landslides controls the variability in solute load of these mountain rivers. We find that systematic patterns in surface water chemistry are strongly associated with landslide occurrence at scales from a single hillslope to an entire mountain belt, and thatA link between chemical weathering and physical erosion exists at the catchment scale over a wide range of erosion rates(1,2). However, in mountain environments, where erosion rates are highest, weathering may be kinetically limited(3-5) and therefore decoupled from erosion. In active mountain belts, erosion is driven by bedrock landsliding(6) at rates that depend strongly on the occurrence of extreme rainfall or seismicity(7). Although landslides affect only a small proportion of the landscape, bedrock landsliding can promote the collection and slow percolation of surface runoff in highly fragmented rock debris and create favourable conditions for weathering. Here we show from analysis of surface water chemistry in the Southern Alps of New Zealand that weathering in bedrock landslides controls the variability in solute load of these mountain rivers. We find that systematic patterns in surface water chemistry are strongly associated with landslide occurrence at scales from a single hillslope to an entire mountain belt, and that landslides boost weathering rates and river solute loads over decades. We conclude that landslides couple erosion and weathering in fast-eroding uplands and, thus, mountain weathering is a stochastic process that is sensitive to climatic and tectonic controls on mass wasting processes.show moreshow less

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Metadaten
Author:Robert Emberson, Niels Hovius, Albert Galy, Odin Marc
DOI:https://doi.org/10.1038/NGEO2600
ISSN:1752-0894
ISSN:1752-0908
Parent Title (English):Nature geoscience
Publisher:Nature Publ. Group
Place of publication:New York
Document Type:Article
Language:English
Year of first Publication:2016
Year of Completion:2016
Release Date:2020/03/22
Volume:9
Pagenumber:6
First Page:42
Last Page:+
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Erd- und Umweltwissenschaften
Peer Review:Referiert