HPCCprojects:Investigating valley spacing regularity on evolving mountain fronts
Investigating valley spacing regularity on evolving mountain fronts
Project description
One of the most striking geomorphological features noticed by many authors on mountain fronts is the apparent regularity in the spacing of river basins. This regularity has been observed also in different geological contexts: orogens (extending mountain fronts), passive margins (e.g. coastal zones, extending fault systems, etc.), as well as in soil mantled low relief landscapes. Such regularity is so striking, that many authors have sought explanations due to primary physical principles and paradigms. Actually, a simple relation involving basin spacing regularity seems to be derivable from Hack's law, which models the scaling of basin area vs. basin length. To support such observations, many experiments have been devoted to simulate landscape evolution through numerical models, to see if such regularity is actually an effect of the fundamental mass-conservation equations which shape the landscapes. For instance, Perron et al. (2008) showed that this may actually be the case, although their experiments are related to small scale basins as in soil mantled low relief landscapes. Recently, experiments were also performed through so-called "hardware" models, i.e. real-world, reduced-scale artificial reproductions of river basins evolving through erosion effects by pouring water. One of these works (Bonnet, 2009) simulated the migration of the drainage divide due to a spatial gradient in precipitation intensity, and observed how river basin regularity seems to be conserved throughout the landscape temporal evolution, on both the extending and the “shrinking” sides of the migrating divide. Some of the suggested mechanisms which could induce river basins to split or converge to maintain constant length-to-width ratio are, however, somewhat controversial.
Objectives
- Is valley spacing maintained through basin evolution as the orogen evolves?
- How do erosion, tectonic and climate process parameters influence valley spacing?
- How is valley spacing maintained during divide migration and how does the fluvial network evolve?
- How do valley spacing change and fluvial network reorganization influence the sediment flux leaving the orogen?
Time-line
- Start: Nov 2010
- End: Nov 2011
Models in use
- CHILD
- SIGNUM
- (other models are under current evaluation)
