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| Titel |
Three grand challenges in geomorphology: rock, climate, and life (Arthur Holmes Medal Lecture) |
| VerfasserIn |
William E. Dietrich |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250058171
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| Zusammenfassung |
| To explain and predict the form and evolution of the earth’s surface we need: mechanistic
understanding of processes; constitutive relationships to solve mass conservation and
transformation equations; analytical and numerical models to assemble and test our
understanding; quantitative metrics of landscapes; and an understanding of the deep history
of the land. New dating methods, high resolution digital elevation data, and a generation of
skilled, creative researchers have led to significant advances. The most difficult
challenges, nonetheless, lie ahead. A 2010 U.S. National Research Council report,
“Landscapes on the Edge”, reviews grand challenges in Earth surface processes. Here I
focus on three grand challenges in geomorphology: to account quantitatively for
how landscape morphodynamics depend on 1) lithology, 2) climate, and 3) life.
These are the surprisingly ordinary factors that simple logic says should matter, and,
indeed, introductory textbooks typically discuss each of these and offer qualitative
inferences that seem reasonable. But take a step towards quantification with a goal
of prediction, and we quickly stop. One can look at these challenges through the
perspective of how one can solve the conservation of mass equation that forms
the basis for predicting surface evolution. For this we need, what can be called
geomorphic transport laws, which are mathematical statements derived from a physical
principle or mechanism, which express the mass flux or erosion caused by one or
more processes in a manner that: 1) can be parameterized from field measurements,
2) can be tested in physical models, and 3) can be applied over geomorphically
significant spatial and temporal scales. Although work has begun, we have little
knowledge yet on how to account in such "laws" for the influences of bedrock, climate,
and life. Some example questions which will be discussed: How can we predict,
mechanistically, the erosion rate of bedrock landscapes? How do processes and
their rates of transport shift with climate? Is there a topographic signature of life? |
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