Temporal buffering of climate-driven sediment flux cycles by transient catchment response

Armitage, John; Jones, Tom Dunkley; Duller, Robert A.; Whittaker, Alexander C.; Allen, Philip A.

doi:10.1016/j.epsl.2013.03.020

Cited by 101 publications

(156 citation statements)

References 61 publications

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“…Whittaker et al, 2007;Cowie et al, 2008;Whittaker and Boulton, 2012), although the precise appropriateness of any time-integrated erosion law to specific field sites is not always easy to establish. Sediment flux response times for the advective stream power law have been previously characterized by Whipple (2001) and Baldwin et al (2003), and for the transport model they have been studied by Armitage et al (2011) and Armitage et al (2013), but not systematically or using 2-D models. Furthermore, to our knowledge no comparison between the transport models has been previously made.…”

Section: Introductionmentioning

confidence: 99%

Numerical modelling of landscape and sediment flux response to precipitation rate change

et al. 2018

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Abstract. Laboratory-scale experiments of erosion have demonstrated that landscapes have a natural (or intrinsic) response time to a change in precipitation rate. In the last few decades there has been growth in the development of numerical models that attempt to capture landscape evolution over long timescales. However, there is still an uncertainty regarding the validity of the basic assumptions of mass transport that are made in deriving these models. In this contribution we therefore return to a principal assumption of sediment transport within the mass balance for surface processes; we explore the sensitivity of the classic end-member landscape evolution models and the sediment fluxes they produce to a change in precipitation rates. One end-member model takes the mathematical form of a kinetic wave equation and is known as the stream power model, in which sediment is assumed to be transported immediately out of the model domain. The second end-member model is the transport model and it takes the form of a diffusion equation, assuming that the sediment flux is a function of the water flux and slope. We find that both of these end-member models have a response time that has a proportionality to the precipitation rate that follows a negative power law. However, for the stream power model the exponent on the water flux term must be less than one, and for the transport model the exponent must be greater than one, in order to match the observed concavity of natural systems. This difference in exponent means that the transport model generally responds more rapidly to an increase in precipitation rates, on the order of 10 5 years for post-perturbation sediment fluxes to return to within 50 % of their initial values, for theoretical landscapes with a scale of 100 × 100 km. Additionally from the same starting conditions, the amplitude of the sediment flux perturbation in the transport model is greater, with much larger sensitivity to catchment size. An important finding is that both models respond more quickly to a wetting event than a drying event, and we argue that this asymmetry in response time has significant implications for depositional stratigraphies. Finally, we evaluate the extent to which these constraints on response times and sediment fluxes from simple models help us understand the geological record of landscape response to rapid environmental changes in the past, such as the Paleocene-Eocene thermal maximum (PETM). In the Spanish Pyrenees, for instance, a relatively rapid (10 to 50 kyr) duration of the deposition of gravel is observed for a climatic shift that is thought to be towards increased precipitation rates. We suggest that the rapid response observed is more easily explained through a diffusive transport model because (1) the model has a faster response time, which is consistent with the documented stratigraphic data, (2) there is a high-amplitude spike in sediment flux, and (3) the assumption of instantaneous transport is difficult to justify for the transport of large grain sizes as an alluvi...

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Section: Introductionmentioning

confidence: 99%

Numerical modelling of landscape and sediment flux response to precipitation rate change

et al. 2018

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“…Armitage et al, 2011Armitage et al, , 2013. However, for sedimentary records over the Holocene and Quaternary scales, we would argue that the changes we are simulating are highly relevant.…”

Section: Discussionmentioning

confidence: 99%

“…It is also worth considering that in our study and that of Simpson and Castelltort (2012) hydraulics and flow processes are simulated and both models show a sensitivity of sediment output/throughput to climate. Whereas Armitage et al (2013) do not simulate the hydraulics and show an insensitivity to climate (essentially impacting water discharge).…”

Section: Discussionmentioning

confidence: 99%

“…different grain size responses to varying uplift) may be missed by different model configurations and parameterizations. For example the recent work by Armitage et al (2011Armitage et al ( , 2013) is based on a one-dimensional model that whilst accounting for slope processes does not explicitly include them within a twodimensional framework. It is also worth considering that in our study and that of Simpson and Castelltort (2012) hydraulics and flow processes are simulated and both models show a sensitivity of sediment output/throughput to climate.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, physical experiments (Bonnet and Crave, 2003) also showed how erosional landscapes responded sharply to climate change. However, Armitage et al (2013) found that sediment response was relatively insensitive to short-term climate variability.…”

Section: Introductionmentioning

confidence: 99%

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Climate, tectonics or morphology: what signals can we see in drainage basin sediment yields?

Coulthard

Wiel

2013

Earth Surf. Dynam.

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Abstract. Sediment yields from river basins are typically considered to be controlled by tectonic and climatic drivers. However, climate and tectonics can operate simultaneously and the impact of autogenic processes scrambling or shredding these inputs can make it hard to unpick the role of these drivers from the sedimentary record. Thus an understanding of the relative dominance of climate, tectonics or other processes in the output of sediment from a basin is vital. Here, we use a numerical landscape evolution model (CAESAR) to specifically examine the relative impact of climate change, tectonic uplift (instantaneous and gradual) and basin morphology on sediment yield. Unexpectedly, this shows how the sediment signal from significant rates of uplift (10 m instant or 25 mm a −1 ) may be lost due to internal storage effects within even a small basin. However, the signal from modest increases in rainfall magnitude (10-20 %) can be seen in increases in sediment yield. In addition, in larger basins, tectonic inputs can be significantly diluted by regular delivery from non-uplifted parts of the basin.

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Tectonics from fluvial topography using formal linear inversion: Theory and applications to the Inyo Mountains, California

2014

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Key Points:• Analytic solution to the stream power model yields a linear inverse problem • A time-space record of uplift rate is inferred from fluvial profiles • Acceleration of relative uplift is inferred for the Inyo range, California, since 2-3Ma Abstract Tectonic activity generates topography, and the variability of tectonic forcing is responsible for topographic patterns and variability of relief in fluvial landscapes. Despite this basic relation, the inverse problem, by which features of the topography are used for inferring tectonic uplift rates, has proven challenging. Here we develop formal linear inversion schemes to infer a record of the rate of relative uplift as a function of space and time from the long profiles of rivers. The relative uplift rate is the difference between the rates of rock uplift and of the base level change. The inversion schemes are based on a closed-form analytic solution to the transient linear stream power model, and to increase model resolution they make use of the multiplicity of information made available by multiple rivers and their tributaries. The distribution of the fluvial response time to tectonic perturbations is a key component of the inversion scheme, as this determines which tectonic events are preserved in the topography. We develop two inversion parameterizations that differ in their assumptions about the tectonic forcing: space-invariant and time-space variability with an assumed spatial distribution. The inversion schemes are applied to the Inyo Mountains, an uplifted block along the western boundary of the Basin and Range Province in California.Inversion results indicate that the range has been experiencing an acceleration of the relative uplift in the past ∼2-3 Ma. We use the inversion results to constrain the paleotopography and paleo-erosion rate along the range and to recover the throw rate history along the fault that bounds the Inyo range.

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Temporal buffering of climate-driven sediment flux cycles by transient catchment response

Cited by 101 publications

References 61 publications

Numerical modelling of landscape and sediment flux response to precipitation rate change

Numerical modelling of landscape and sediment flux response to precipitation rate change

Climate, tectonics or morphology: what signals can we see in drainage basin sediment yields?

Tectonics from fluvial topography using formal linear inversion: Theory and applications to the Inyo Mountains, California

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