Sedimentology and modeling in the Mitterndorf pull-apart basin (Plio-/Pleistocene, Austria)

Projekt: Forschungsförderung

Projektdetails

Projektergebnis

The project achieved a new, high resolution 4-dimensional model of the Quaternary Mitterndorf basin, a sub-basin of the Vienna Basin. The evolution of the basin during the last 250.000 years was reconstructed based on the integration of a wealth of data, and simulated using numerical models, leading to new findings on the climate history and the climatic and tectonic control of sedimentation and landscape evolution.
Project outcomes include the localisation of fault planes by integrated methods, i.e., data from 2000 drillings, seismic, geoelectric and geomorphic data. Derivates of geophysical gravity measurements were also used for the first time. The sedimentary fill of the basin was analyzed and correlated in outcrops and bore holes. Sediment types and sedimentary environments were interpreted, indicating the strong influence of climatic changes on fluvial deposits and the formation of alluvial fans (Schwarza and Piesting fans) in the southern part of the basin. Analysis of heavy minerals allowed the identification and interpretation of source areas und the distinction from young Danube deposits. Comprehensive mollusc analysis gives information on past climatic and environmental conditions and the age of the sediments.
Using data from a scientific drilling the sedimentary succession in the depth of the basin up to 170 m was cleared up. Absolute dating methods like C14 and OSL combined with palaeomagnetics allowed for the first time an accurate dating of the Mitterndorf basin. Fine-grained basal units of a warm period after 250.000 years are followed by ice-age gravels and another warm period corresponding to the Riss-Würm Interglacial at 130.000 years before past. This section is overlain by Wuermian ice-age gravels. On the alluvial fans deposition ended around 10.000 years. Deposition was then restricted to the Holocene floodplain.
4-dimensional process modelling of the alluvial fans in the south of the basin indicated the interplay of climate change and tectonics (basin subsidence). Large-scale basin fill geometries (sequences) are controlled mainly by climatic changes from cold (coarse-grained sediments, i.e. gravels, coarse river bedload, braided streams, formation of alluvial fans) to warm (fine-grained sediments, meandering rivers, soil formation). Tectonics (earth quakes), climate, drainage area size, and confinement of depositional areas controlled the type, geometry and thickness of individual fan bodies.
Our data can be used for refinement of ground water models in the Vienna Basin.
StatusAbgeschlossen
Tatsächlicher Beginn/ -es Ende1/12/0531/03/09