Structural evolution and imaging of fold-thrust structures in analog models deformed in a large geotechnical centrifuge.

摘要

This thesis investigates the structural evolution of fold-thrust systems by scaled physical analog modelling carried out in a large geotechnical centrifuge at C-CORE, St. Johns, NL. Multilayer models are constructed of plasticine and silicone putty to simulate foreland stratigraphic sequences and are shortened horizontally to simulate the nucleation and temporal development of individual fold-thrust structures and fold-thrust systems as a whole. The models accurately reconstruct the structural evolution and geometrical development of critically tapered wedges, duplex structures and individual fold-thrust structures.; Plane-layered models composed of five internally laminated stratigraphic units of alternating bulk competency develop geologically realistic duplex structures. An evolutionary relationship between folding and faulting exists; the low-amplitude buckling instability of the competent unit localizes and controls the spacing of thrust ramps in duplex structures. (Abstract shortened by UMI.)