NUMERICAL MODELING OF FORELAND BASIN FORMATION - A PROGRAM RELATING THRUSTING, FLEXURE, SEDIMENT GEOMETRY AND LITHOSPHERE RHEOLOGY

An algorithm has been developed which allows the flexural deflection o f the lithosphere to be calculated under thrust loading and the geomet ry of the sedimentary infill in the adjacent foreland basin. To that p urpose we have considered arbitrarily shaped thrust-load systems movin g towards the foreland, and surface processes denudating the orogen an d filling the basin. The regional compensation of topographic loads is based on the assumption that the lithosphere behaves as a thin prate with either homogeneous (elastic, viscoelastic) behavior or more reali stic depth-dependent elastic-plastic rheology. When using heterogeneou s rheology, the program calculates the flexural behavior as a function of crustal geometry and thermal regime of the lithosphere, thus relat ing the basin infill geometry with the deep lithosphere properties. We show some examples where the geometry of the basin and sedimentary in fill (e.g. onlap/toplap patterns) are generated assuming different lit hosphere rheologies and synthetic tectonic contexts which support the applicability of the model to study the formation and evolution of for eland basins. (C) 1998 Elsevier Science Ltd. All rights reserved.