Influence of multiple décollement and cover rock rheology on the structural evolution of thin-skinned fold-and-thrust belts: insights from discrete element modelling

A variety of thin-skinned fold-and-thrust belts are associated with multiple décollements, which have low frictional basal and intermediate décollements related to mechanical stratigraphy or overpressure conditions. The present study considers six ternary series numerical discrete element (DE) models simulate explore the effects varied décollement layers, number cover sequences thickness in structural style, evolution, strain partitioning belts. Horizontal layer-parallel shortening particles was induced by horizontal motion a vertical boundary wall. modelling results show weak promoted decoupled deformation belt continues shortening. indicate that mainly accommodating thrust-related folds significant differences style. formation décollement, box, fault-propagation, fault-bend folds, as well extensional faults represents ultimate style developed DE-models. DE-models thin fewer demonstrate box-shaped less secondary disharmonic limbs main fold structures. Furthermore, thickest upper characterized decoupling, more flow material into core anticlinal structures complicated this decoupling can be affected rheology, number, décollements. DE-modelling compared natural examples, analogue models, our overall match different