Autogenic Organization of Syn‐Tectonic Sedimentary Patterns in Deepwater Foldbelts: A Simple Dynamic Model

Abstract

We present a dynamical model that links through multiple length and time scales the formation of detachment folds, degradation of topography, and deposition of sheet‐like sedimentary bodies in deepwater foldbelt environments based on a nonlinear reaction–diffusion equation. We represent the stratigraphic response predicted by our model in a two‐dimensional parametric space whose axes are given by the Peclet number (Pe), the ratio of the mass transported by tectonic uplift and the mass transferred by diffusive hillslope processes, and the sediment delivery number (Sd), the ratio of sediments transported by density currents to those produced by intrabasinal processes. Notably, we identify three well‐defined regions of sedimentary behavior in that parametric space: a central domain (Pe > 2,Sd > 2) of cyclic stratigraphy produced by self‐sustained oscillations in the sedimentary system and two regions near the graph axes of stable sedimentation in which a continuous stratigraphy is produced. In the central domain, all the mass fluxes are equally important. This creates the conditions for a series of complex interaction between hillslope sediment transport, fold growth, and sedimentation. The other two regions correspond to end‐members in which either the Pe or Sd is small. For small Pe values, topographic degradation and sediment dispersal by hillslope transport dominate over tectonic uplift. Thus, any tectonic perturbation appearing in the system dissipates readily. For small Sd values, sediment transport is dominated by creep, and the system rapidly evolves toward a steady state.

A New Method for Fault‐Scarp Detection Using Linear Discriminant Analysis in High‐Resolution Bathymetry Data From the Alarcón Rise and Pescadero Basin

“…In addition, it has been used in the long‐term modeling of turbidity flows (Schlager & Adams, 2001; Spinewine et al., 2011; Steckler et al., 1999). Nonlinear diffusive models have also been used to simulate degradation in deepwater foldbelts (Lotero‐Vélez et al., 2019). We test Equation 2 through inversion in the bathymetric profiles in SPB to match these marine landforms’ evolution, assuming diffusion operates the same in continental and marine systems.…”

“…We test Equation 2 through inversion in the bathymetric profiles in SPB to match these marine landforms’ evolution, assuming diffusion operates the same in continental and marine systems. Numerical models (Lotero‐Vélez et al., 2019) of sediment dispersal in marine environments indicate that this assumption is valid where hillslope transport dominates over either topographic buildup or wash load (Andrews & Hanks, 1985). By contrast, sedimentation becomes unstable (nonlinear) along slopes when the sediment supply and tectonic uplift exceed hillslope transport (Andrews & Bucknam, 1987).…”