Formation of evenly spaced ridges and valleys
One of the most striking examples of self-organization in landscapes is the emergence of evenly spaced ridges and valleys. Despite the prevalence of uniform valley spacing, no theory has been shown to predict this fundamental topographic wavelength. Models of long-term landscape evolution can pro...
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Nature Publishing Group
2011
|
| Online Access: | http://hdl.handle.net/1721.1/64681 https://orcid.org/0000-0002-0404-8701 |
| Summary: | One of the most striking examples of self-organization in landscapes is the
emergence of evenly spaced ridges and valleys. Despite the prevalence of
uniform valley spacing, no theory has been shown to predict this fundamental
topographic wavelength. Models of long-term landscape evolution can produce
landforms that look realistic, but few metrics exist to assess the similarity
between models and natural landscapes. Here we show that the ridge-valley
wavelength can be predicted from erosional mechanics. From equations of mass
conservation and sediment transport, we derive a characteristic length scale at
which the timescales for erosion by diffusive soil creep and advective stream
incision are equal. This length scale is directly proportional to the valley spacing
that emerges in a numerical model of landform evolution, and to the measured
valley spacing at five field sites. Our results provide a quantitative explanation for
one of the most widely observed characteristics of landscapes. They also imply that
valley spacing is a fundamental topographic signature that records how material
properties and climate regulate erosional processes. |
|---|