@article{fdi:010092628,
  title = {{E}vidence of slow millennial cliff retreat rates using cosmogenic nuclides in coastal colluvium},
  author = {{B}ossis, {R}. and {R}egard, {V}. and {C}arretier, {S}{\'e}bastien and {C}hoy, {S}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he erosion of rocky coasts contributes to global cycles of elements over geological times and also constitutes a major hazard that may potentially increase in the future. {Y}et, it remains a challenge to quantify rocky coast retreat rates over millennia - a time span that encompasses the stochasticity of the processes involved. {S}pecifically, there are no available methods that can be used to quantify slow coastal erosion (< 1 cm yr(-1)) averaged over millennia. {H}ere, we use the {B}e-10 concentration in colluvium, corresponding to the by-product of aerial rocky coast erosion, to quantify the local coastal retreat rate averaged over millennia. {W}e test this approach along the {M}editerranean coast of the eastern {P}yrenees (n=8) and the desert coast in southern {P}eru (n=3). {W}e observe a consistent relationship between the inferred erosion rates and the geomorphic contexts. {T}he retreat rates are similar, 0.3-0.6 mm yr(-1) for five samples taken on the {M}editerranean coast, whereas two samples from vegetated colluvium have a lower rate of similar to 0.1 mm yr(-1). {T}he coastal retreat rate of the {P}eruvian site currently subject to wave action is similar to the {M}editerranean coast (0.5 mm yr(-1)), despite {P}eru's more arid climate. {T}he other two {P}eruvian sites, which have not been subjected to wave action for tens of thousands of years, are eroding 20 times more slowly. {T}he integration periods of the two slowest {M}editerranean coast erosion rates may encompass pre-{H}olocene times, during which the sea level and thus the retreat rate were much lower. {W}e explore here this bias and conclude that the associated bias on the inferred retreat rate is less than 80 %. {T}hese data show that rocky coasts are eroding 1 to 20 times faster than catchments in the same regions on average over the last few thousand years. {W}e anticipate that this new method of quantifying slow rocky coastal erosion will fill a major gap in the coastal erosion database and improve our understanding of both coastal erosion factors and hazards.},
  keywords = {{FRANCE} ; {PEROU} ; {MEDITERRANEE}},
  booktitle = {},
  journal = {{E}arth {S}urface {D}ynamics},
  volume = {13},
  numero = {1},
  pages = {71--79},
  ISSN = {2196-6311},
  year = {2025},
  DOI = {10.5194/esurf-13-71-2025},
  URL = {https://www.documentation.ird.fr/hor/fdi:010092628},
}