Pace of Meandering and Avulsion Set River Sinuosity near Coast on Earth and Mars
Abstract
Lowland meandering rivers typically become less sinuous towards their outlets. This landscape feature has traditionally been considered a hallmark of fluvial-deltaic system and provided the basis for interpreting channel and shoreline dynamics of ancient fluvial-deltaic systems on Earth and Mars. The downstream decrease in sinuosity has been hypothesized to arise due to spatially varying channel hydraulics and floodplain composition near the coast. However, we lack quantitative constraints on how these factors affect the temporal variability in sinuosity within the life cycle of a channel that is set by delta-scale river avulsion. Here, we evaluated a group of lowland rivers and found that sinuosity within the backwater zone near the coast typically increases significantly or remain relative constant, depending on both the backwater-controlled avulsion time scale and channel lateral migration rate. We hypothesize that both flood variability and sediment supply drive this spatial variability in sinuosity. Furthermore, we found channels from two Martian deltas with the signature of increased sinuosity around avulsion nodes, information that can be used to better constrain paleohydrology on the Mars.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMEP31A..07W