Uplift histories from river profiles

Pritchard, David; Roberts, G.G.; White, Nicky; Richardson, Chris N.

doi:10.1029/2009gl040928

Cited by 176 publications

(234 citation statements)

References 23 publications

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“…This history is consistent with the conceptual model presented in Fig. 2 and supports the findings of numerous other studies that show that river profiles are sensitive recorders of relative uplift histories (Snyder et al, 2000;Whipple, 2001, 2012;Wobus et al, 2006;Whittaker et al, 2008;Boulton and Whittaker, 2009;Pritchard et al, 2009;Whittaker and Boulton, 2012;Perron and Royden, 2013;Royden and Perron, 2013;Goren et al, 2014;Whittaker and Walker, 2015).…”

Section: Along-strike Patternssupporting

confidence: 79%

“…Transient landscapes, those landscapes in the process of adjusting to newly imposed boundary conditions, provide the opportunity to interrogate topography for information regarding the timing and magnitude of landscape adjustment to external forcing. As such, studies of transient landscapes have received considerable attention over the past 15 years and serve as a cornerstone of modern tectonic geomorphological studies Whipple, 2001, 2012;Wobus et al, 2006;Pritchard et al, 2009;Perron and Royden, 2013;Royden and Perron, 2013;Gallen et al, 2013;Goren et al, 2014). Most studies that seek to extract tectonic and climate signals from fluvial landscapes rely on river profile analysis; the interpretation of the geometry of river longitudinal profiles, mostly in the context of the detachment-limited river incision model (Howard, 1994;Whipple and Tucker, 1999).…”

Section: Introductionmentioning

confidence: 99%

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River profile response to normal fault growth and linkage: an example from the Hellenic forearc of south-central Crete, Greece

2017

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Abstract. Topography is a reflection of the tectonic and geodynamic processes that act to uplift the Earth's surface and the erosional processes that work to return it to base level. Numerous studies have shown that topography is a sensitive recorder of tectonic signals. A quasi-physical understanding of the relationship between river incision and rock uplift has made the analysis of fluvial topography a popular technique for deciphering relative, and some argue absolute, histories of rock uplift. Here we present results from a study of the fluvial topography from south-central Crete, demonstrating that river longitudinal profiles indeed record the relative history of uplift, but several other processes make it difficult to recover quantitative uplift histories. Prior research demonstrates that the south-central coastline of Crete is bound by a large ( ∼ 100 km long) E-W striking composite normal fault system. Marine terraces reveal that it is uplifting between 0.1 and 1.0 mm yr −1 . These studies suggest that two normal fault systems, the offshore Ptolemy and onshore South-Central Crete faults, linked together in the recent geologic past (ca. 0.4-1 My BP). Fault mechanics predict that when adjacent faults link into a single fault the uplift rate in footwalls of the linkage zone will increase rapidly. We use this natural experiment to assess the response of river profiles to a temporal jump in uplift rate and to assess the applicability of the stream power incision model to this setting. Using river profile analysis we show that rivers in south-central Crete record the relative uplift history of fault growth and linkage as theory predicts that they should. Calibration of the commonly used stream power incision model shows that the slope exponent, n, is ∼ 0.5, contrary to most studies that find n ≥ 1. Analysis of fluvial knickpoints shows that migration distances are not proportional to upstream contributing drainage area, as predicted by the stream power incision model. Maps of the transformed stream distance variable, χ, indicate that drainage basin instability, drainage divide migration, and river capture events complicate river profile analysis in south-central Crete. Waterfalls are observed in southern Crete and appear to operate under less efficient and different incision mechanics than assumed by the stream power incision model. Drainage area exchange and waterfall formation are argued to obscure linkages between empirically derived metrics and quasi-physical descriptions of river incision, making it difficult to quantitatively interpret rock uplift histories from river profiles in this setting. Karst hydrology, break down of assumed drainage area discharge scaling, and chemical weathering might also contribute to the failure of the stream power incision model to adequately predict the behavior of the fluvial system in south-central Crete.

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Section: Along-strike Patternssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

River profile response to normal fault growth and linkage: an example from the Hellenic forearc of south-central Crete, Greece

2017

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“…(11) would be a migrating wave of erosion travelling either up or down the catchment (Braun et al, 2015). This wave could also potentially take the form of a shock wave, in which due to the change in gradient the lower reaches of the migrating wave could travel faster than the upper reaches, creating a breaking wave (Smith et al, 2000;Pritchard et al, 2009). The time evolution of Eq.…”

Section: Erosion Within a Single Dimension Systemmentioning

confidence: 99%

“…When river-long profiles are inverted for uplift, erosion is typically assumed to be captured by the stream power model (e.g. Pritchard et al, 2009). Studies of continent-scale inversion have found that the best fit value of k for the stream power model increases by 2 orders of magnitude to fit river profiles in Africa relative to Australia (Rudge et al, 2015).…”

Section: Response Times As a Function Of Model Choicementioning

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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“…Furthermore, many workers have used the framework of the stream power incision model to extract uplift histories (Pritchard et al, 2009;Roberts and White, 2010;Fox et al, 2014;Goren et al, 2014). However, the ability of these studies to extract information from channel profiles is dependent on the concavity index and the slope exponent, n, which are key unknowns within these theoretical models 25 of fluvial incision.…”

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confidence: 99%

How concave are river channels?

Mudd¹,

Clubb²,

Gailleton³

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 relationship be-5 tween channel gradient and drainage area is referred to as channel concavity, and despite being crucial in determining channel steepness, is challenging to constrain. In this contribution we compare both slope-area methods for calculating concavity 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 channel concavity in transient landscapes without assuming a linear relationship between χ and elevation. Patterns of 10 channel concavity 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 15 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 concavity varies across diverse landscapes, with the aim to improve our understanding of the physics behind bedrock channel incision.

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Uplift histories from river profiles

Cited by 176 publications

References 23 publications

River profile response to normal fault growth and linkage: an example from the Hellenic forearc of south-central Crete, Greece

River profile response to normal fault growth and linkage: an example from the Hellenic forearc of south-central Crete, Greece

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

How concave are river channels?

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