ORCID
- Mather, Anne: 0000-0001-6634-8681
- Stokes, Martin: 0000-0003-3788-4615
Abstract
An understanding of rates and mechanisms of incision and knickpoint retreat in bedrock rivers is fundamental to perceptions of landscape response to external drivers, yet only sparse field data are available. Here we present eye witness accounts and quantitative surveys of rapid, amphitheatre-headed gorge formation in unweathered granite from the overtopping of a rock-cut dam spillway by small-moderate floods (~100–1,500 m3 s−1). The amount of erosion demonstrates no relationship with flood magnitude or bedload availability. Instead, structural pattern of the bedrock through faults and joints appears to be the primary control on landscape change. These discontinuities facilitate rapid erosion (>270 m headward retreat; ~100 m incision; and ~160 m widening over 6 years) principally through fluvial plucking and block topple. The example demonstrates the potential for extremely rapid transient bedrock erosion even when rocks are mechanically strong and flood discharges are moderate. These observations are relevant to perceived models of gorge formation and knickpoint retreat.
DOI
10.1038/ncomms8963
Publication Date
2015-06-29
Publication Title
Nature Communications
Volume
6
ISSN
2041-1723
Organisational Unit
School of Geography, Earth and Environmental Sciences
Recommended Citation
Anton, L., Mather, A., Stokes, M., Muñoz-Martin, A., & De, V. (2015) 'Exceptional river gorge formation from unexceptional floods', Nature Communications, 6. Available at: https://doi.org/10.1038/ncomms8963
