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

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 (S-d), 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,S-d > 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 S-d 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 S-d values, sediment transport is dominated by creep, and the system rapidly evolves toward a steady state.