PETERSEN, KENNETH, and IAN LERCHE, Department of Geological Sciences, University of South Carolina, Columbia, SC

ABSTRACT: Simulation of the Interactive Process of Diapirism and Sedimentation

Different numerical methods are able to describe the deposition and deformation of particles flowing around a rising body of simple geometry. Simulating buoyant diapirism and sedimentation self-consistently implies building a coordinate grid that is unique to the diapiric shape and evolves with the shape. Because diapiric structures can have evolved overhangs, the constructed grid must handle double-valued lateral coordinates. A deformable grid is constructed by a recursive procedure based on the shape of the rising body at each stage of its deformation, where each primary gridline is parallel to its neighbor with a fixed perpendicular offset (delta epsilon). The inevitable occurrence of singularites forces construction of a secondary grid that, superposed on the primary grid, allows he modeled particle flow to simulate properly the sedimentation process in nature. Particles move around the rising body in a semi-fluid manner, following paths uniquely determined by the composite grid with the important non-fluid property that compressibility is possible and allowed. An inverse non-linear procedure determines the shape- and geometrical parameters most consistent with the final state of diapirism and sedimentation. A detailed discussion is provided of the novel dynamic shape-grid system with emphasis on effects of numerical precision and resolution.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.