Using Cosmogenic Nuclide Measurements In Sediments To Understand Background Rates Of Erosion And Sediment Transport

Bierman, Paul R.; Clapp, Erik M.; Nichols, Kyle K.; Gillespie, Alan R.; Caffee, Marc W.

doi:10.1007/978-1-4615-0575-4_5

Cited by 31 publications

(38 citation statements)

References 24 publications

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“…However, comparisons of the dimensionless relief and erosion rate performed by Grieve et al (2016b) highlight the small-scale topographic variability inherent in this otherwise regular landscape. The Oregon Coast Range is considered to be in steady state due to the correlation between uplift rates from marine terrace data (Kelsey et al, 1996) and erosion rates from cosmogenic radionuclides (Beschta, 1978;Reneau and Dietrich, 1991;Bierman et al, 2001;Heimsath et al, 2001). The hillslopes are steeper and the ridgelines sharper than in Gabilan Mesa, consistent with observations of debris flows and shallow landsliding across the range (Dietrich and Dunne, 1978;Heimsath et al, 2001;Montgomery, 2001), which have the potential to create a distinct topographic signature (Booth et al, 2009).…”

Section: Oregon Coast Rangementioning

confidence: 81%

How does grid-resolution modulate the topographic expression of geomorphic processes?

et al. 2016

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Abstract. In many locations, our ability to study the processes which shape the Earth are greatly enhanced through the use of high-resolution digital topographic data. However, although the availability of such datasets has markedly increased in recent years, many locations of significant geomorphic interest still do not have highresolution topographic data available. Here, we aim to constrain how well we can understand surface processes through topographic analysis performed on lower-resolution data. We generate digital elevation models from point clouds at a range of grid resolutions from 1 to 30 m, which covers the range of widely used data resolutions available globally, at three locations in the United States. Using these data, the relationship between curvature and grid resolution is explored, alongside the estimation of the hillslope sediment transport coefficient (D, in m 2 yr −1 ) for each landscape. Curvature, and consequently D, values are shown to be generally insensitive to grid resolution, particularly in landscapes with broad hilltops and valleys. Curvature distributions, however, become increasingly condensed around the mean, and theoretical considerations suggest caution should be used when extracting curvature from landscapes with sharp ridges. The sensitivity of curvature and topographic gradient to grid resolution are also explored through analysis of one-dimensional approximations of curvature and gradient, providing a theoretical basis for the results generated using two-dimensional topographic data. Two methods of extracting channels from topographic data are tested. A geometric method of channel extraction that finds channels by detecting threshold values of planform curvature is shown to perform well at resolutions up to 30 m in all three landscapes. The landscape parameters of hillslope length and relief are both successfully extracted at the same range of resolutions. These parameters can be used to detect landscape transience and our results suggest that such work need not be confined to high-resolution topographic data. A synthesis of the results presented in this work indicates that although high-resolution (e.g., 1 m) topographic data do yield exciting possibilities for geomorphic research, many key parameters can be understood in lower-resolution data, given careful consideration of how analyses are performed.

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Section: Oregon Coast Rangementioning

confidence: 81%

How does grid-resolution modulate the topographic expression of geomorphic processes?

et al. 2016

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“…In addition to these sedimentary units, our selected landscape also contains the Yachats Basalt, which erupted mostly as sub-areal flows between 3 and 9 m in thickness during the late Eocene (Davis et al, 1995). Erosion rates inferred from 10 Be concentrations in stream sediments are between 0.11 to 0.14 mm yr −1 (Heimsath et al, 2001;Bierman et al, 2001), similar to rock uplift rates of 0.05-0.35 mm yr −1 inferred from marine terraces (Kelsey et al, 1994). Short-term erosion rates derived from stream sediments fall into the range of 0.07 to 0.18 mm yr −1 (Wheatcroft and Sommerfield, 2005), leading a number of authors to suggest that the Coast Range is in topographic steady state, where uplift is balanced by erosion (e.g.…”

Section: An Example Of Lithologic Variabilitymentioning

confidence: 97%

How concave are river channels?

et al. 2018

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Abstract. For over a century, geomorphologists have attempted to unravel information about landscape evolution, and processes that drive it, using river profiles. Many studies have combined new topographic datasets with theoretical models of channel incision to infer erosion rates, identify rock types with different resistance to erosion, and detect potential regions of tectonic activity. The most common metric used to analyse river profile geometry is channel steepness, or k s . However, the calculation of channel steepness requires the normalisation of channel gradient by drainage area. This normalisation requires a power law exponent that is referred to as the channel concavity index. Despite the concavity index being crucial in determining channel steepness, it is challenging to constrain. In this contribution, we compare both slope-area methods for calculating the concavity index and methods based on integrating drainage area along the length of the channel, using so-called "chi" (χ) analysis. We present a new χ-based method which directly compares χ values of tributary nodes to those on the main stem; this method allows us to constrain the concavity index in transient landscapes without assuming a linear relationship between χ and elevation. Patterns of the concavity index have been linked to the ratio of the area and slope exponents of the stream power incision model (m/n); we therefore construct simple numerical models obeying detachment-limited stream power and test the different methods against simulations with imposed m and n. We find that χ-based methods are better than slope-area methods at reproducing imposed m/n ratios when our numerical landscapes are subject to either transient uplift or spatially varying uplift and fluvial erodibility. We also test our methods on several real landscapes, including sites with both lithological and structural heterogeneity, to provide examples of the methods' performance and limitations. These methods are made available in a new software package so that other workers can explore how the concavity index varies across diverse landscapes, with the aim to improve our understanding of the physics behind bedrock channel incision.

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“…The measurement of 10 Be and 26 Al in fluvial, hillslope, and cave sediments is another geologically important use of these nuclides. Because Bierman et al (2001a) and Granger and Muzikar (2001) have recently reviewed the measurement and application of 10 Be in quartz-bearing sediments; such use is not reviewed here in any detail.…”

Section: Illustrative Case Studiesmentioning

confidence: 99%

“…Some of this work was reviewed in Bierman et al (2001a), but more recent studies include an erosion rate survey based on sediments of some European rivers (Schaller et al 2001), a mountain scale study in the Great Smoky Range of southeastern North America (Matmon et al 2001a,b), a study of the 16,000 km 2 Rio Puerco basin (northern New Mexico, USA; Bierman et al 2001c), and recent work in the Sierra Nevada of California documenting the influence of tectonics and the lack of influence of climate on rates of bedrock erosion (Riebe et al 2000(Riebe et al , 2001a. Analysis of 10 Be and 26 Al in buried pebbles allowed calculation of both source rock erosion rates (mostly 2-12 m Myr -1 ) and rates of river incision (~30 m Myr -1 ) in the southern Appalachian Mountains of eastern North America, presumably in response to climate and long-term isostatic uplift (Granger et al 1997.…”

Section: Estimating Bedrock Erosion Ratesmentioning

confidence: 99%

Rates and Timing of Earth Surface Processes From In Situ-Produced Cosmogenic Be-10

Bierman

Caffee

Davis

et al. 2002

Reviews in Mineralogy and Geochemistry

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Using Cosmogenic Nuclide Measurements In Sediments To Understand Background Rates Of Erosion And Sediment Transport

Cited by 31 publications

References 24 publications

How does grid-resolution modulate the topographic expression of geomorphic processes?

How does grid-resolution modulate the topographic expression of geomorphic processes?

How concave are river channels?

Rates and Timing of Earth Surface Processes From In Situ-Produced Cosmogenic Be-10

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