Erosion during extreme flood events dominates Holocene canyon evolution in northeast Iceland

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: Baynes, Edwin R. C., Attal, Mikaël, Niedermann, Samuel, Kirstein, Linda A., Dugmore, Andrew J., Naylor, Mark
• Format: Text
• Language: English
• Published: National Academy of Sciences 2015
• Subjects: Physical Sciences; Iceland
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4345614; http://www.ncbi.nlm.nih.gov/pubmed/25675484; https://doi.org/10.1073/pnas.1415443112

The importance of high-magnitude, short-lived events in controlling the evolution of landscapes is not well understood. This matters because during such events, erosion processes can surpass thresholds and cause abrupt landscape changes that have a long-lasting legacy for landscape morphology. We show that extreme flood events, during which the flow depth exceeds the threshold for erosion through plucking rather than abrasion, are the dominant control on the evolution of a large bedrock canyon in Iceland. The erosive signature of these events is maintained within a dynamic landscape over millennial timescales, emphasizing the importance of episodic extreme events in shaping landscapes.