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| Titel |
The role of climate change in drainage network reorganization: insights from numerical experiments |
| VerfasserIn |
E. Giachetta, N. Gasparini, D. Capolongo, A. Refice, F. J. Pazzaglia |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250065251
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| Zusammenfassung |
| The topography of mountain belts reflects the complex interactions among climate, tectonics
and erosion, but it is often difficult to interpret the geomorphological signals of this interplay
in a landscape. The continuous feedbacks among tectonics, surface processes, and climate
change are reflected in the distribution of catchments on active mountain fronts. Previous
studies (e.g. Hovius, 1996) have shown a certain regularity of valley spacing on several
mountain ranges worldwide, but what is at the origin of such geomorphological feature
of landscapes is currently not well known. Recently, studies using analogue and
numerical models (Bonnet et al.; 2009, Perron et al., 2009) have attempted to explain
and interpret quantitatively the formation of evenly spaced valleys along mountain
fronts.
In this work, we illustrate numerical experiments of long-term landscape evolution of an
active mountain range, using our TIN-based landscape evolution model, SIGNUM (Refice et.
al, 2012), simulating tectonic uplift, hillslope diffusion, river erosion and climate change. In
particular, building on some preliminary results (Capolongo et al., 2011), we show how the
constant valley spacing, achieved at steady state on both sides of the range, is progressively
restored after simulating a migration of the main drainage divide caused by a precipitation
gradient applied across the mountain belt. Here, we explain how the pattern of catchments
evolves on the two sides of the range, using a sequence of snapshots of the transient
topography extracted from the model results. We analyze the time evolution of
the spacing ratio R (Hovius,1996; Wallace, 1978), defined as the ratio between
the half-width W of the belt and the spacing S of the outlets of the catchments
draining from the main drainage divide. We consider R as an index describing the
degree of catchment reorganization on both the windward and leeward sides of the
belt. Finally, we present analogies between the synthetic landscapes extracted from
the numerical simulations and real landscapes with similar tectonic and climatic
conditions.
References
Bonnet, S. (2009). Shrinking and splitting of drainage basins in orogenic landscapes from
the migration of the main drainage divide. Nature Geoscience. 2, 766-771.
Capolongo, D., Refice, A., and Giachetta, E (2011). Investigating valley spacing
dynamics in linear mountain fronts through terrain numerical modeling, EGU Abstracts.
Hovius, N. (1996), Regular spacing of drainage outlets from linear mountain belts. Basin
Research, 8, 29 -44.
Perron, J. T., Kirchner, J. W. & Dietrich, W. E. (2009). Formation of evenly spaced ridges
and valleys. Nature 460, 502-505.
Refice, A. Giachetta, E., Capolongo, D. (2012). SIGNUM: a Matlab, TIN-based
landscape evolution model, Computers and Geosciences, in press.
Wallace, R.E. (1978). Geometry and rate of changes of fault-generated range fronts,
northcentral Nevada. J. Res. US Geol. Surv., 6, 637-650. |
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