Geometric rules for cutoff development in meandering streams across landscapes and seascapes on Earth and Mars

Session: Geomorphology and Surface Processes Across the Solar System

Presenting Author:

Chenliang Wu

Authors:

Wu, Chenliang¹, Kim, Wonsuck², Keum, Duhwan³, Kim, Minsik⁴, Jung, Sojung⁵, Kwon, Junsung⁶, Lee, Jiyoung⁷, Shin, Haein⁸, Herring, Ryan⁹, Odugbesan, Oluwadamilare¹⁰, Straub, Kyle¹¹

(1) Tulane University, New Orleans, LA, USA, (2) Yonsei University, Seoul, Korea (The Republic of), (3) GFZ German Research Center for Geosciences, Potsdam, Germany, (4) Yonsei University, Seoul, Korea (The Republic of), (5) Yonsei University, Seoul, Korea (The Republic of), (6) Yonsei University, Seoul, Korea (The Republic of), (7) Yonsei University, Seoul, Korea (The Republic of), (8) Yonsei University, Seoul, Korea (The Republic of), (9) Brown University, Providence, USA, (10) Tulane University, New Orleans, USA, (11) Tulane University, New Orleans, USA,

Abstract:

Meandering streams are dynamic geomorphic features that develop across a wide range of landscapes and seascapes, including alluvial, tidal, deepwater, glacial, and bedrock environments. These streams continuously alter their courses through lateral channel migration and the formation of cutoffs, which are ubiquitous in meandering systems worldwide. There are two primary types of cutoffs: neck cutoffs and chute cutoffs. A neck cutoff occurs when a meandering channel erodes into itself through lateral migration, while a chute cutoff takes place when a new and shorter channel (i.e., chute channel) develops that short circuits the longer pre-existing flow path. To date, we lack a mechanistic model for predicting the location and timing of chute cutoff occurrence. To address this knowledge gap, we compiled a new global dataset of meander cutoffs from diverse systems including alluvial, tidal, deepwater, glacial meltwater, and bedrock streams on Earth, as well as inverted fluvial sandstone ridges on Mars. Using this dataset, we test the hypothesis that chute cutoffs develop once a channel reaches a critical sinuosity threshold. Preliminary results show that: (1) the sinuosity of channel bends where chute channels initiate follows a log-normal distribution across all systems; (2) there is no distinct break in distributions of cutoff distances to reliably separate neck and chute cutoffs, with chute cutoffs comprising approximately 90% of all observed cases; and (3) the locations of chute channel entrances relative to the pre-cutoff channel bend are normally distributed around the bend apex. These findings represent an important step toward a mechanistic understanding of meandering stream dynamics and provide the basis for the development of more advanced numerical models of meander evolution.