title: Time scale bias in erosion rates of glaciated landscapes.
abstract: Deciphering erosion rates over geologic time is fundamental for understanding the interplay between climate, tectonic, and erosional processes. Existing techniques integrate erosion over different time scales, and direct comparison of such rates is routinely done in earth science. On the basis of a global compilation, we show that erosion rate estimates in glaciated landscapes may be affected by a systematic averaging bias that produces higher estimated erosion rates toward the present, which do not reflect straightforward changes in erosion rates through time. This trend can result from a heavy-tailed distribution of erosional hiatuses (that is, time periods where no or relatively slow erosion occurs). We argue that such a distribution can result from the intermittency of erosional processes in glaciated landscapes that are tightly coupled to climate variability from decadal to millennial time scales. In contrast, we find no evidence for a time scale bias in spatially averaged erosion rates of landscapes dominated by river incision. We discuss the implications of our findings in the context of the proposed coupling between climate and tectonics, and interpreting erosion rate estimates with different averaging time scales through geologic time.
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Vamsi
authors.initials: V
authors.lastname: Ganti
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Christoph
authors.initials: C
authors.lastname: von Hagke
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Dirk
authors.identifier: 0000-0003-3911-2803
authors.initials: D
authors.lastname: Scherler
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Lamb
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Woodward W
authors.initials: WW
authors.lastname: Fischer
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Jean-Philippe
authors.identifier: 0000-0002-3060-8442
authors.initials: JP
authors.lastname: Avouac
keywords: Erosion; climate variability; glaciers; power-law; river incision; timescale dependence