Glacial conditioning as an erosional driving force in the Central Alps

Norton, Kevin; Abbühl, Luca M.; Schlunegger, Fritz

doi:10.1130/g31102.1

Cited by 104 publications

(111 citation statements)

References 28 publications

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“…While it is difficult to assess our snow shielding estimates, we note the rela- tive effect on erosion rates is similar to those based on snowdepth measurements within other snowy orogens (Wittmann et al, 2007;Norton et al, 2010;Scherler et al, 2013).…”

Section: Cosmogenic Basin-averaged Erosion Ratesmentioning

confidence: 91%

Tectonic controls of Holocene erosion in a glaciated orogen

Adams

Ehlers

2018

Earth Surf. Dynam.

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Abstract. Recent work has highlighted a strong, worldwide, alpine glacial impact on orogen erosion rates over the last 2 Ma. While it may be assumed that glaciers increased erosion rates when active, the degree to which past glaciations influence Holocene erosion rates through the adjustment of topography is not known. In this study, we investigate the influence of long-term tectonic and post-glacial topographic controls on erosion in a glaciated orogen: the Olympic Mountains, USA. We present 14 new 10 Be and 26 Al analyses which constrain Holocene erosion rates across the Olympic Mountains. Basin-averaged erosion rates scale with basin-averaged values of 5 km local relief, channel steepness, and hillslope angle throughout the range, similar to observations from non-glaciated orogens. These erosion rates are not related to mean annual precipitation or the marked change in Pleistocene alpine glacier size across the range, implying that glacier modification of topography and modern precipitation parameters do not exert strong controls on these rates. Rather, we find that despite spatial variations in glacial modification of topography, patterns of recent erosion are similar to those from estimates of long-term tectonic rock uplift. This is consistent with a tectonic model where erosion and rock uplift patterns are controlled by the deformation of the Cascadia subduction zone.

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Section: Cosmogenic Basin-averaged Erosion Ratesmentioning

confidence: 91%

Tectonic controls of Holocene erosion in a glaciated orogen

Adams

Ehlers

2018

Earth Surf. Dynam.

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“…We base our analyses on previous studies where uplift (longand short-term), glacial inheritance, precipitation and erosional resistance of the underlying bedrock have been invoked to explain the landscape's characteristics, expressed through variables such as mean elevation, hypsometry, relief, hillslope gradients and longstream profiles (Kühni and Pfiffner, 2001;Wittmann et al, 2007;Norton et al, 2010b;Schlunegger and Norton, 2013;Snyder et al, 2000). We test these relationships through correlation and statistical analyses, and we conclude that variations in erodibility explain most of the morphometric variations that we can observe within the Rhône Basin.…”

Section: Organization Of the Papermentioning

confidence: 99%

“…However, much less attention has been paid to exploring how the tectonic architecture, and the nature of the bedrock lithology in particular, has driven surface erosion and has conditioned the shape of the Alpine landscape (Kühni and Pfiffner, 2001;Norton et al, 2010b), mainly because the spatial and temporal variability of uplift, climate, glacial cover and lithology Kühni and Pfiffner, 2001;Bini et al, 2009) complicates an integrated understanding of the erosional patterns and the resulting landscape form in this orogen. Nevertheless, because of the obvious spatial variation in bedrock lithology, the Alps offer an ideal laboratory to explore whether landscape properties on the basin scale (mean elevation, hypsometry, relief, hillslope gradients and stream profile shapes) are mainly grouped around identical lithologies or around other conditions and driving forces (long-and short-term uplift, climate, etc.).…”

Section: Motivation For This Studymentioning

confidence: 99%

“…The Central European Alps have been intensively studied regarding how surface and crustal-scale processes have been coupled through time and how effects related to these mechanisms have been modulated by glacial erosion and deposition (see, e.g., Persaud and Pfiffner, 2004;Gudmundsson, 1994;Champagnac et al, 2007;Schlunegger and Hinderer, 2001;Cederbom et al, 2011;Norton et al, 2010b;Schlunegger and Norton, 2013). However, much less attention has been paid to exploring how the tectonic architecture, and the nature of the bedrock lithology in particular, has driven surface erosion and has conditioned the shape of the Alpine landscape (Kühni and Pfiffner, 2001;Norton et al, 2010b), mainly because the spatial and temporal variability of uplift, climate, glacial cover and lithology Kühni and Pfiffner, 2001;Bini et al, 2009) complicates an integrated understanding of the erosional patterns and the resulting landscape form in this orogen.…”

Section: Motivation For This Studymentioning

confidence: 99%

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Lithological control on the landscape form of the upper Rhône Basin, Central Swiss Alps

2016

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Abstract. The development of topography depends mainly on the interplay between uplift and erosion. These processes are controlled by various factors including climate, glaciers, lithology, seismic activity and short-term variables, such as anthropogenic impact. Many studies in orogens all over the world have shown how these controlling variables may affect the landscape's topography. In particular, it has been hypothesized that lithology exerts a dominant control on erosion rates and landscape morphology. However, clear demonstrations of this influence are rare and difficult to disentangle from the overprint of other signals such as climate or tectonics.In this study we focus on the upper Rhône Basin situated in the Central Swiss Alps in order to explore the relation between topography, possible controlling variables and lithology in particular. The Rhône Basin has been affected by spatially variable uplift, high orographically driven rainfalls and multiple glaciations. Furthermore, lithology and erodibility vary substantially within the basin. Thanks to high-resolution geological, climatic and topographic data, the Rhône Basin is a suitable laboratory to explore these complexities.Elevation, relief, slope and hypsometric data as well as river profile information from digital elevation models are used to characterize the landscape's topography of around 50 tributary basins. Additionally, uplift over different timescales, glacial inheritance, precipitation patterns and erodibility of the underlying bedrock are quantified for each basin.Results show that the chosen topographic and controlling variables vary remarkably between different tributary basins. We investigate the link between observed topographic differences and the possible controlling variables through statistical analyses. Variations of elevation, slope and relief seem to be linked to differences in long-term uplift rate, whereas elevation distributions (hypsometry) and river profile shapes may be related to glacial imprint. This confirms that the landscape of the Rhône Basin has been highly preconditioned by (past) uplift and glaciation. Linear discriminant analyses (LDAs), however, suggest a stronger link between observed topographic variations and differences in erodibility. We therefore conclude that despite evident glacial and tectonic conditioning, a lithologic control is still preserved and measurable in the landscape of the Rhône tributary basins.

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“…While it is difficult to assess our snow shielding estimates, we note the relative effect on erosion rates is similar to those based on snow-depth measurements within other snowy orogens (Wittmann et al, 2007;Norton et al, 2010;Scherler et al, 2013). 280…”

Section: Cosmogenic Basin-averaged Erosion Rates 255mentioning

confidence: 99%

Tectonic controls of Holocene erosion in a glaciated orogen

Adams¹,

Ehlers²

2018

Preprint

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Abstract. Recent work has highlighted a strong, worldwide, glacial impact of orogen erosion rates over the last 2 Ma. While it may be assumed that glaciers increased erosion rates when active, the degree to which past glaciations influence Holocene erosion rates through the adjustment of topography is not known. In this study, we investigate the influence of long-term tectonic and post-glacial topographic controls on erosion in a glaciated orogen, the Olympic Mountains, USA. We present 14 10 new 10 Be and 26 Al analyses which constrain Holocene erosion rates across the Olympic Mountains. Basin-averaged erosion rates scale with basin-averaged values of 5-km local relief, channel steepness, and hillslope angle throughout the range, similar to observations from non-glaciated orogens. These erosion rates are not related to mean annual precipitation or the marked change in Pleistocene alpine glacier size across the range, implying that glacier modification of topography and modern precipitation parameters do not exert strong controls on these rates. Rather, we find that despite intense spatial variations in 15 glacial modification of topography, patterns of recent erosion are similar to those from estimates of long-term tectonic rock uplift. This is consistent with a tectonic model where erosion and rock uplift patterns are controlled by the deformation of the Cascadia subduction zone.

show abstract

Glacial conditioning as an erosional driving force in the Central Alps

Cited by 104 publications

References 28 publications

Tectonic controls of Holocene erosion in a glaciated orogen

Tectonic controls of Holocene erosion in a glaciated orogen

Lithological control on the landscape form of the upper Rhône Basin, Central Swiss Alps

Tectonic controls of Holocene erosion in a glaciated orogen

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