『Abstract
Sediment erosion laws form the basis for most landscape evolution
models and guide geomorphologists in the pursuit of understanding
how landscapes evolve. This focus on the alluvial surface, however,
ignores the role of intrinsic feedbacks between sediment transport
and bedrock weathering in shaping Earth's landforms. Here, we
present a new, parsimonious explanation for the origin and maintenance
of pediments, piedmont junctions, and tors, which emerge spontaneous;y
in a numerical model coupling bedrock weathering and sediment
transport. The spatial uniformity of the thin regolith mantle
that often characterizes pediments is a manifestation of a negative
feedback between bedrock weathering and regolith thickness: if
regolith thins (thickens) by sediment transport, the regolith
production rate will increase (decrease), maintaining an equilibrium
regolith thickness on the piedmont. We propose that high infiltration
capacities and the instability of ephemeral channel banks in arid
and semiarid environments suppress fluvial incision and promote
the smoothness of pediments. A positive feedback between bedrock
weathering and regolith thickness causes for growth: if regolith
thins locally below a critical value, regolith production slows
while surrounding areas continue to weather and erode more rapidly.
we suggest that many pedimented and tor-studded landscapes may
therefore be a consequence of intrinsic sediment transport-weathering
feedbacks mediated by climatic and tectonic conditions, not by
lithologic templates.
Keywords: pediments; tors; regolith; weathering; deserts.』
Introduction
Simulations of pediment development
Emergent landscape features
Conclusion
Acknowledgments
References cited