Erosion in the Chilean Andes between 27°S and 39°S: Tectonic, climatic and geomorphic control

S. Carretier, V. Tolorza, M. P. Rodríguez, E. Pepin, G. Aguilar, V. Regard, J. Martinod, R. Riquelme, S. Bonnet, S. Brichau, G. Hérail, L. Pinto, M. Farías, R. Charrier, J. L. Guyot

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

The effect of mean precipitation rate on erosion is debated. Three hypotheses may explain why the current erosion rate and runoff may be spatially uncorrelated: (1) the topography has reached a steady state for which the erosion rate pattern is determined by the uplift rate pattern; (2) the erosion rate only depends weakly on runoff; or (3) the studied catchments are experiencing different transient adjustments to uplift or to climate variations. In the Chilean Andes, between 27°S and 39°S, the mean annual runoff rates increase southwards from 0.01 to 2.6 m a-1 but the catchment averaged rates of decadal erosion (suspended sediment) and millennial erosion (10Be in river sand) peak at c. 0.25 mm a-1 for runoff c. 0.5 m a-1 and then decrease while runoff keeps increasing. Erosion rates increase non-linearly with the slope and weakly with the square root of the runoff. However, sediments trapped in the subduction trench suggest a correlation between the current runoff pattern and erosion over millions of years. The third hypothesis above may explain these different erosion rate patterns; the patterns seem consistent with, although not limited to, a model where the relief and erosion rate have first increased and then decreased in response to a period of uplift, at rates controlled by the mean precipitation rate.

Original languageEnglish
Pages (from-to)401-418
Number of pages18
JournalGeological Society Special Publication
Volume399
DOIs
Publication statusPublished - 1 Jan 2015

ASJC Scopus subject areas

  • Water Science and Technology
  • Ocean Engineering
  • Geology

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