Strike-slip tectonics and Quaternary basin formation along the Vienna Basin fault system inferred from Bouguer gravity derivatives

Abstract

The Vienna Basin at the transition between the Alpine and Carpathian belt hosts a number of large Pleistocene sub-basins forming along an active continental scale strike-slip fault (Vienna Basin strike-slip fault). We utilize first-order derivatives from industrial Bouguer gravity data to unravel the impacts of Pleistocene kinematics on the Vienna Basin and to compensate for the lack of near-surface fault data. Anomalies have been evaluated by independent geophysical and geological data and were integrated to build up a tectonic model. Factors influencing the wavelength and the amplitude of anomalies were additionally investigated by 2-D models to better interpret field data. Subsidence and related accumulation of Quaternary sediments in the Vienna Basin produce significant gravity signals related to the activity of the strike-slip fault. The constrained fault patterns and structures highlight tight and elongated transtensional pull-apart basins with typically associated features like separated depocenters and Riedel fractured sidewalls in an en-echelon alignment. Further Pleistocene basins are highlighted as tectonic grabens developing along branches of the master fault. The Vienna Basin is additionally affected by minor deformation represented by both subsidence along major Miocene sidewalls and NW-SE faulting resulting in distinct topographic features, which manifests kinematics on a regional scale. The clear density contrasts between Miocene marine and Quaternary terrestrial sediments, as well as the exceptional database, provide a unique framework to demonstrate advantages of incorporating gravity derivatives for near-surface fault analysis.