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WINGEOL / SEDTEC, NEW SOFTWARE FOR MODELLING EROSION & DEPOSITION

Robert Faber & Michael Wagreich
Institut für Geologie, Universität Wien, robert.faber@univie.ac.at

WinGeol/SedTec is a software package developed at the Institute of Geology (University of Vienna), which simulates erosion and deposition in dependency of topography, fault movements, lithological properties and sea level.

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Fig. 1 Principles of WinGeol/SedTec:A: Sediment transport induced by elevation or concentration differencesB: Transport mechanism used for modelling

Sediment transport is induced by elevation or concentration differences between neighbouring cells. In the first case a topographic driven mass transport is generated, in the second case sediment transport due to suspension is modelled.

Grain size reduction during sediment transport is distance and materials dependent. The spatial distribution of different rock types are extracted automatically from a lithological raster map at the beginning of the simulation process. Rock types are characterized by their resistance to erosion and grain size reduction during sediment transport. The progress of the simulation can be checked with control point data, which define maximum sedimentation rates at predefined locations.

Deposited material is compacted due to the weight of the overload. An algorithm, which can handle fluid movements induced by the overburden, is in development.

Input data for simulation include elevation, lithology, fault data and tabular data from various data sets:
· digital elevation model (simple plane or real world model)
· fault data (optional)
· lithological raster map (optional)
· lithological parameters (resistance to erosion, ...)
· sea level (single value or curve)
· control points (optional)

Faults are defined by the following parameters:
· geographic position
· start and end time of activity
· displacement vector (direction and length)
· translation and/or rotation

Examples simulated with WinGeol/SedTec include landscape development due to erosion and sedimentation, deformations due to translation and rotations of several fault blocks, erosion and deposition along a steep scarp (Fig. 2A) and grain size distributions in grabens (Fig. 2B) and pull apart basins.

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Fig. 2 WinGeol/SedTec examples: A: Erosion of a steep scarpB: Simulation of a Graben structure, the 3D graph displays the different erosions rates due to lithological resistivity contrasts (in the profile the left side is much more eroded due to this contrasts).