Understanding the role of décollement thickness on the evolution of décollement folds: insights from discrete element models

Abstract

We explored the influence of a variety of geometric and mechanical factors in the evolution of décollement folds above a weak décollement level in a sedimentary sequence. Under an applied overburden pressure, we construct nine discrete element models (DE-models) to test the effects of mechanical stratigraphy, the thickness of the décollement layer, and the number of strong and weak layers within the sedimentary cover sequence. The effects of the aforementioned parameters on the structural style of fold belts and the mechanical evolution of décollement folds that develop during a progressive deformation are what we are searching for. The one-way lateral motion of a rigid, vertical boundary wall was used to shorten the particle assemblage. The models presented in this study were then compared to a natural structure in Iran and demonstrated that the combined effects of mechanical behaviour, the thickness of décollement layer, and the number of strong and weak layers within the sedimentary cover sequence are playing the decisive role in the structural style, kinematic and mechanical evolution of décollement folds.

Keywords

• Discrete element modelling
• Structural style
• Kinematics
• Mechanical evolution
• Fault-related folding
• Décollement folding
• Discrete element modelling