Year: 2024
Type: article
Abstract: Notch development at the base of sea cliffs is an important control on cliff recession rates, but a detailed mechanistic understanding of notch formation by swash abrasion is lacking. We conducted physical experiments, using homogeneous erodible rock simulants, to study notch‐forming mechanisms under periodic sediment‐laden bore impacts. Our findings reveal shifts in the temporal dynamics of notch development. Initially, swash uprush and vortex formation contribute to a positive feedback loop that creates a shallow and wide notch. Subsequently, upward erosion ceases, and notch backwear and downwear are dominated by the vortex. Eventually, sediment deposition armors the notch floor; this negative feedback loop reduces erosion. The sediment size determines the amount of erosion, with a range of grain sizes generating maximum erosion. This indicates a dependence on the momentum of the sediment particles entrained within the bore. This research reveals fundamental notch formation mechanisms driven by swash abrasion.
Source: Geophysical Research Letters
DOI: 10.1029/2024gl112175
Institution: University of Auckland
Language: English
Topic: Coastal and Marine Dynamics
Subfield: Earth-Surface Processes
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,900
OpenAlex ID: W4402943094