| The complex relationship between folding and faulting in global fold-and-thrust belts has led to the development of a number of models, both two and three dimensional, aiming to accurately pinpoint the nature of faulting and the origins of various fold geometries. These fold geometries range from very broad, rounded fold forms to extremely localized, sharp-hinged, flat-topped folds. Previous studies have used different modeling styles to characterize the varying types of fault-related folds. The two main categories of modeling, kinematic/geometric reconstructions and mechanical models, both have their respective advantages and disadvantages.;Previous work has been focused more towards kinematic/geometric constructions, with less attention paid to the mechanical modeling methods that take into account the physical conditions that form fault-related folds. However, minimal work has explored what effect flexural layer-parallel slip has on mechanical models of fault-related folds.;For the purposes of this study a code, Boundary Element Analysis of Flexural Slip (BEAFS), was developed as a way to recreate multiple fold form geometries by varying a range of physical conditions, thereby helping to shed light on the role of layer-parallel slip. BEAFS is a code that allows for the deformation of an elastic layered medium undergoing frictional slip. A dipping fault is embedded within the medium with a lower detachment and/or an upper detachment. Initial work with BEAFS has been aimed towards defining the physical conditions responsible for the formation of end-member typed fold geometries. The physical conditions that can be manipulated are the thickness and number of layers, coefficient of friction (range 0-0.8), and initial uniform differential stress (horizontal-vertical) before folding (range 0-10MPa).;The study has determined that thickly-layered mediums/mediums with bonded contacts produce rounded, broad fold geometries, regardless of the fault geometry. With a fault-propagation fold geometry, thin-layered mediums with freely slipping layers form concentric folds localized above fault tip; in fault-bend fold geometries kink-banded, flat-crested folds will form. Introducing friction into a FPF geometry with thin layers will generate kink-banding and the addition of a farfield stress to most models will enhance development of kink-bands regardless of fault shape. Continuing work will be focused on using BEAFS to try and recreate first-order geometries of folds seen in seismic reflection data to better understand the role of layer-parallel slip. |
