Stratigraphic simulation in Neogene basins of Austria: the influence of synsedimentary tectonics on stratigraphic sequences.

Research project P 13740 Stratigraphic simulation in Neagene basins, Austria Micahel WAGREICH 28.06.1999 The aim of the project is the computer simulation of stratigraphy and sedimentology within Neogen Miocene basins of Austria to investigate the role tectonic movements, sediment supply and eustastic changes of sea level. The forward modelling of stratigraphic sequences comprises a major tool for the interpretation of the complex interplay of eustasy and tectonics in the formation of stratal architectures of sedimentary basin fills. It gives the possibility to quantify the importance of controlling factors of sediment deposition and geometries such as sediment volume and type, subsidence, compaction, loading, and erosion rates. Special interest will be on the effects of geodynamic events expressed by e.g. synsedimentary tectonics and local and regional basin subsidence and uplift. The PHIL and the SEDPAK software packages will be used for computer modelling. The project will concentrate on selected case studies within a few time slices, where the sedimentology and stratigraphy of the basin fill are well known. These case areas inlude the Miocene in the Vienna Basin, especially the area around the Matzen oil field, small intramontaneous basins of the Mur-Mürz fault system, e.g. the Fohnsdorf Basin, and the Köflach-Voitsberg area, where non-marine deposits and coal occur, and the Molasse foreland basin, where the role of Alpine tectonics and the uplift/denudation history of the Eastern Alpine orogene will be evaluated. A common feature of these case areas is the influence of synsedimentary tectonic on deposition. A detailed facies analysis and environmental interpretation is necessary for computer simulations. Standard sedimentological methods such as sedimentological logs and grain size analysis are used together with data on fossil assemblages. The project is part of the project cluster "Changes in Eastern Alpine Miocene Ecosystems and their Geodynamic Control"

The aim of the project was the computer simulation of sediment geometries within Neogene (ca. 18 - 7 my) sedimentary basins of Austria to investigate the role of tectonic movements, sediment supply and changes of sea level. New basin models have been achieved for the central Vienna Basin and the Fohnsdorf Basin. The role of faulting during the evolution of the Vienna Basin was quantitatively reconstructed. A new modelling software package (WinGeol/SedTec by R. Faber) was successfully developed and may be applied to further basin research projects and industrial oil exploration. The forward modelling of stratigraphy comprises a major tool for the interpretation of the driving mechanisms in the formation of sedimentary basin fills and gives the possibility to quantify sedimentation. Special interest was on the effects of geodynamic events expressed by basin subsidence and uplift. The project concentrated on case studies in the Vienna Basin and the Fohnsdorf Basin and related basins in Styria and Carinthia. Simulation runs in the Vienna Basin were based on industrial data from OMV. A common feature of these case studies was the influence of tectonic deformation on deposition. Dating of lithological units was assisted by Strontium isotope measurements, which have been compared to standard curves. The newly developed modelling software WinGeol/SedTec simulates erosion and deposition in dependency on topography, tectonic movements, lithological properties and sealevel. It is based on the principle of a neighborhood matrix and can simulate sedimentation during faulting. The project was part of the project cluster "Changes in Eastern Alpine Miocene Ecosystems and their Geodynamic Control".