Climate control on the relationship between erosion rate and fluvial topography

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1130/G50832.1. This is version 4 of this Preprint.

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Authors

Eyal Marder, Sean F Gallen

Abstract

Conceptual and theoretical models for landscape evolution suggest that fluvial topography is sensitive to climate. However, it remains challenging to demonstrate a compelling link between fluvial topography and climate in natural landscapes. One possible reason is that many studies compare erosion rates to climate data, although theoretical studies show that, at steady state, climate is encoded in the relationship between erosion rate and topography rather than erosion rate alone. We use an existing global compilation of 10Be basin-averaged erosion rates to isolate the climate signal in topography as a function of erosion rate for morphologically steady-state, fluvially dominated basins underlain by crystalline bedrock. Our results show that the relationship between erosion rate (a proxy for rock uplift rate) and the normalized river channel steepness index (a proxy for fluvial relief) becomes increasingly nonlinear with increasing mean annual precipitation and decreasing aridity. This result indicates that erosional efficiency increases in wetter and more humid climates, lowering fluvial relief for a given erosion rate. When interpreted in the context of detachment-limited bedrock incision models that account for incision thresholds and stochastic flood distributions, this systematic pattern can be explained by a decrease in discharge variability in wetter and more humid landscapes, assuming incision thresholds are important on a global scale.

DOI

https://doi.org/10.31223/X5DS6B

Subjects

Earth Sciences, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics

Keywords

climate, Fluvial topography, Discharge variability, landscape evolution

Dates

Published: 2022-03-05 01:17

Last Updated: 2023-03-14 02:24

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License

CC BY Attribution 4.0 International

Additional Metadata

Conflict of interest statement:
None