| Flexural slip is considered to be an important folding mechanism contributing in the development of different folds such as chevron, and kink-band buckle folds. Various filed studies have provided a general conceptual and qualitative understanding of flexural slip. However, quantitative evidence of the importance of the flexural slip mechanism during fold evolution is sparse, as the actual amount of surface parallel displacement, and timing, is difficult to measure accurately, due to the lack of suitable strain markers.;In this study 2D finite element analysis is used to overcome these disadvantages and to simulate flexural slip during viscoelastic buckle folding. Variations of single and multilayer layer fold configurations are investigated, showing that flexural slip is most likely to occur in effective single layer buckle folds where slip occurs between contacts of competent units. Based on the effective single layer buckle folds the influence of the number of slip surfaces, the degree of mechanical coupling (based on friction coefficient), and bedding unit thickness, on the resulting slip distribution are investigated.;The results are in agreement with the conceptual flexural slip model and show that slip is initiated sequentially during the deformation history and is maximum in the center of the fold limb. The cumulative amount of slip increases as the number of bedding contacts is increased. For a lower degree of mechanical coupling different fold shapes, such as box folds, result during buckling. In comparison with laboratory experiments, geometrical relationships and field observations the numerical modeling results show similar slip magnitudes as observed in the field. It is concluded that flexural slip may represent a significant contribution during buckle folding and may affect the resulting fold shape. |
