Geodynamical models of geological processes

Our research concerns lithospheric tectonic processes and the interactions among the lithosphere, the underlying convecting mantle, and overlying hydrosphere and atmosphere. The lithosphere, the Earth's strong outer layer, is central to the plate tectonic view of the Earth. Contrary to early plate tectonic concepts lithospheric plates are not rigid. Although plate boundaries are where most deformation occurs, continental interiors in particular experience significant deformation. Our research is motivated by the need for a quantitative understanding of the deformation of the lithosphere and its surficial sedimentary cover. The goal is to determine how such geodynamical processes contribute to the geological record. Our scientific approach to these problems is to develop and use numerical geodynamical models (primarily finite element models) as analogues to natural systems. The model experiments combine basic underlying processes in a framework in which the sensitivity of the model results to a range of hypotheses/propositions is examined. The results are then compared with observations from natural systems. The ability to compute self-consistent model evolutions under controlled conditions (as in sensitivity analyses) leads to insight into the controls of the model dynamics. The novelty of this approach is that complex systems can be simplified by isolating the key driving processes and their interactions, thereby leading to hypotheses concerning the operation of equivalent natural systems. We report progress and propose new research on the following problems: 1) Lithospheric scale convergent tectonics; 2) Lithospheric extension and the formation of rifted continental margins; 3) Continental margin salt and shale tectonics, and; 4) Thin-skinned thrust-and-fold belts. We also describe progress in: 5) Development of new techniques (coupling of mechanical deformation and Darcy fluid flow in porous sediments and crust, and collaborative research on the development of 3D finite element software).