TECTONICS, EROSION, AND SEDIMENTATION IN AN OVERTHRUST SYSTEM - A NUMERICAL-MODEL

The frontal overthrust structures of a collision ridge and its forelan d basin together form an area where the movement of imbricated overthr ust structure, erosion, sedimentation, and substratum subsidence occur simultaneously. These various phenomena interact and lead to a subseq uent sequence of exhumations and burying of the sheets forming these s tructures. Separate models have been developed in Turbo Pascal for eac h of these phenomena (imbricate movement, erosion, sedimentation, diff erential subsidence of the bedrock) and these models are coupled in a general algorithm. By changing the values of the geometrical and mecha nical parameters, it is possible to study and quantify the effect of v arious phenomena on the development and tectonic history of the collis ion ridge front. Ancillary programs for reconstructing the geometry of the sedimentary bodies of the transported basins and the series of cr oss sections also were developed and are used to analyze the geometry predicted by the models and to compare them with natural examples.