Video
Abstract
This presentation explores the dynamics of meandering systems in both fluvial and submarine environments, focusing on the predictability of channel migration and the resulting stratigraphic heterogeneities. Traditional models relating migration rate to the radius of curvature often lack predictive power due to their non-linear and noisy nature. Migration rates become significantly more predictable when using a physics-based model that considers the weighted sum of upstream curvatures, which accounts for a spatial lag between maximum curvature and maximum migration.
A key contribution of this work is the quantification of the point bar to counterpoint bar spectrum using a newly introduced “Bar Type Index”. Counterpoint bars, characterized by concave bank deposition and high silt/mud content, develop where the curvature vector and migration vector point in opposite directions. This index allows for better prediction of lithological heterogeneities within meandering successions.
The talk further addresses the role of autogenic processes in shaping stratigraphy. In incisional systems, meandering can produce complex terrace sequences and significant stratigraphic gaps purely through internal dynamics, as illustrated by Wheeler diagrams. In submarine settings, plan-view migration patterns are qualitatively similar to fluvial systems. The presentation introduces the concept of “auto-aggradation” in submarine channels, where increasing sinuosity over time leads to a decrease in slope, forcing a transition from incision to aggradation — a phenomenon that can be explained without requiring external sea-level changes.
Event
Nordic Sedimentary Research Group Annual General Meeting, January 5, 2021.