This image dataset contains results (original top-view and cross-section photographs) obtained from a series of 12 crustal-scale physical analogue modelling experiments performed in the Tectonic Modelling Laboratory (TecLab) at Utrecht University. We employed analogue modelling to study the inversion of extensional basins that are parallel and oblique to their boundaries. The key parameters of this study are: (i) the obliquity angle (0°, 10° or 20°) of shortening in relation to the strike of the initial rift structures; (ii) the basal décollement rheology; and (iii) the rheology of the basin fill.
All analogue experiments are rectangular, 2 cm thick and consist of deformable brittle or brittle–ductile layers. Deformable parts in entirely brittle models are made of a homogeneous layer of quartz sand for the initial, non-stretched, pre-rift model crust. The subsequently resulting grabens are filled with syn- to post-extensional sediments of quartz sand, feldspar sand, or glass beads. Variations to these setups entail either a brittle layer of glass beads at the base of the above described brittle crust, or, for brittle-ductile models, a viscous layer of PDMS silicone putty with fillers. All experiments are built on one fixed above two mobile plastic sheets, their transition is pre-defining velocity discontinuities (VDs). In a first stage, deformation is induced in all models by two electric motors pulling the two mobile plastic sheets in opposite directions parallel to the backstop. These sheets are then fixed once the extensional phase is finished. VDs positioned both orthogonally and obliquely with respect to the backstop allow graben structures to form at angles of 0°, 10° and 20° to the subsequent shortening direction. In a second stage, a rigid backstop moves into the model to create compressive deformation within the entirely brittle or brittle-ductile layers. Top-view photographs were taken at regular time intervals throughout each experiment (see below for details). Cross-section photographs were taken at the end of each experiment. Therefore, the top-view photographs enable surface deformation to be tracked and analysed through time and space, while the cross-sections demonstrate the overall vertical deformation of each model.
For more details about the models, see Sieberer et al. (2023). The properties of the materials used are described in Sieberer et al. (2023), Klinkmüller et al. (2016) and Willingshofer et al. (2018). All models are scaled according to the principles of geometric, rheological, and kinematic similarity between nature and models (Hubbert, 1937; Weijermars & Schmeling, 1986).
This image dataset contains results (original top-view and cross-section photographs) obtained from a series of 4 crustal-scale physical analogue modelling experiments performed in the Tectonic Modelling Laboratory (TecLab) at Utrecht University. The experiments have been designed to allow comparison with the European eastern Southern Alps but are also relevant for other regions where lateral mechanical and structural heterogeneities within fold-and-thrust belts of inverted rift structures occur. Key features of our experiments include: (i) a predefined basin and platform configuration following Sieberer et al. (2023) and representing the result of Triassic to Jurassic rifting, (ii) a platform with lateral strength variations representing compositional heterogeneity related to Permian igneous activity and (iii) a basal plate representing an inherited basement structure.
All analogue experiments are rectangular, maximum 2.0 cm thick, and are made of deformable layers only, except for Model 4 where a rigid basal plate is partly incorporated. The deformable part of all models is made of one homogeneous layer of dry quartz sand for the pre-defined post-rift model crust. The pre-defined platform and basin geometry yields lateral strength differences controlled by differences in layer thickness, with thinner (1.4 cm) compartments simulating overall weaker, rifted basin domains (e.g., alternations of limestone, marl, clay) compared to the thicker (1.8 to 2.0 cm) platform succession, simulating continental upper crust (e.g., basement rocks, carbonate platforms, volcanic rocks). All experiments are built on a table and on top of a fixed plastic sheet of 0.05 cm thickness and are shortened orthogonal to the backstop at a rate of 3 cm/h. We decided for simple orthogonal inversion models with shortening parallel to the axis of the eastern platform.
Top-view photographs were taken at regular time intervals throughout each experiment (see below for details). Cross-section photographs were taken at the end of each experiment. Therefore, the top-view photographs enable surface deformation to be tracked and analysed through time and space, while the cross-sections demonstrate the overall vertical deformation of each model.
For more details about the models, see Sieberer et al. (2025). The properties of the materials used are described in Sieberer et al. (2025) and Willingshofer et al. (2018). All models are scaled according to the principles of geometric, rheological, and kinematic similarity between nature and models (Hubbert, 1937; Weijermars & Schmeling, 1986).