Exceptional river gorge formation from unexceptional floods

56Citations
Citations of this article
75Readers
Mendeley users who have this article in their library.

This article is free to access.

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 m 3 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.

Cite

CITATION STYLE

APA

Anton, L., Mather, A. E., Stokes, M., Muñoz-Martin, A., & De Vicente, G. (2015). Exceptional river gorge formation from unexceptional floods. Nature Communications, 6. https://doi.org/10.1038/ncomms8963

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free