 |
| Titel |
Deformation and evolution of an experimental drainage network subjected to oblique deformation: Insight from chi-maps |
| VerfasserIn |
Laure Guerit, Liran Goren, Stephane Dominguez, Jacques Malavieille, Sebastien Castelltort |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250141939
|
| Publikation (Nr.) |
 EGU/EGU2017-5498.pdf |
|
|
|
|
|
| Zusammenfassung |
| The morphology of a fluvial landscape reflects a balance between its own dynamics and
external forcings, and therefore holds the potential to reveal local or large-scale tectonic
patterns. Commonly, particular focus has been cast on the longitudinal profiles
of rivers as they constitute sensitive recorders of vertical movements, that can be
recovered based on models of bedrock incision. However, several recent studies have
suggested that maps of rescaled distance along channel called chi (χ), derived from the
commonly observed power law relation between the slope and the drainage area ,
could reveal transient landscapes in state of reorganization of basin geometry and
location of water divides. If river networks deforms in response to large amount of
distributed strain, then they might be used to reconstruct the mode and rate of horizontal
deformation away from major active structures through the use of the parameter χ.
To explore how streams respond to tectonic horizontal deformation, we develop
an experimental model for studying river pattern evolution over a doubly-vergent
orogenic wedge growing in a context of oblique convergence. We use a series of
sprinklers located about the experimental table to activate erosion, sediment transport
and river development on the surface of the experimental wedge. At the end of
the experiment, the drainage network is statistically rotated clockwise, confirming
that rivers can record the distribution of motion along the wedge. However, the
amount of rotation does not match with the imposed deformation, and thus we infer
that stream networks are not purely passive markers. Based on the comparison
between the observed evolution of the fluvial system and the predictions made from
χ maps, we show that the plan-view morphology of the streams results from the
competition between the imposed deformation and fluvial processes of drainage
reorganization. |
|
|
|
|
|
|