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Understanding the development of foreland-foredeep systems and the influence exerted by pre-existing structures on their evolution is an important step for defining the key factors that control long-term basin and lithosphere dynamics, comprehending the associated seismic hazard and assessing their economic potential in the domain of hydrocarbon exploration. The Po Valley is a rather unique foreland basin for two major reasons: a) it developed intermittently at the front of two different mountain chains, the Northern Apennines and the Southern Alps, progressively converging one towards the other; b) the inherited structures, mainly derived from the Mesozoic extensional tectonics, are oriented at high angle to the advancing belts. The coexistence of these two factors and their various implications make the Po Valley basin a complex case study that deserves attention. Taking advantage of the recent building of a 3D structural model across the region, we reconstructed the possible geometry and migration pattern of the Tertiary basins that developed at the front of the Northern Apennines and the Southern Alps, as part of the Po Valley tectonic evolution. In addition, a number of sections sliced from the 3D model across selected domains have then been used to restore the present-day structural units to their pre-compressional setting, while highlighting the key stages of their geological history. Results from the model analysis show that the Mesozoic extension-related tectonics and the associated carbonate facies geometry and distribution localized and constrained the Alpine structures inside/around the basin. Their control on the Cenozoic deformation and sedimentation is evident during the Paleogene and the Miocene whereas it becomes more subtle during the Plio-Pleistocene when lithospheric-scale mechanisms need to be invoked. Notwithstanding the model uncertainties and its explicit regional significance, our results may be taken as reference for any foreland-foredeep setting worldwide, especially in complex systems where tectono-sedimentary inhomogeneity is spatially and temporally dominant. [ABSTRACT FROM AUTHOR]

The Po Valley (Northern Italy) is a composite foreland–foredeep basin caught in between the Southern Alps and Northern Apennine mountain belts. By integrating the 3D structural model of the region with the public earthquake dataset, the seismo-tectonics of the basin is shown at different scales of observation. The three-dimensional geo-volume is used to review the seismicity around the region and validate the structure–earthquake association for such a complex tectonic framework. Despite the overall uncertainty due to the original data distribution-quality as well as the crustal scale model dimension, the direct correlation between structures and seismicity a) confirms the Po Valley region as an active tectonic system and b) allows the whole structural architecture to be revised by a unique three-dimensional perspective and approach. This study also indicates that 3D methodology is a powerful tool for better understanding of highly complex seismo-tectonic situations at both regional and local scales. [ABSTRACT FROM AUTHOR]

Abstract: A 3D structural model of the Po Valley basin (Northern Italy) was built by integrating the dataset available from the public domain (DEM, wells, isobath-maps, cross-sections, outcrop-trends). The model shows the complex foredeep-foreland architecture across the basin, from the Moho level to the topography while illustrating the top Basement, top Triassic, top Mesozoic and base-Pliocene surface-grid structures. The results, by model slicing and isopach-map reconstruction, suggest that the deep Moho architecture and the original tectonics of the ancient Adria-Po Valley passive continental margin are key factors in controlling the current structures type, orientation and distribution, at any of the shallowest levels across the basin. In particular, the analysis of the final 3D Mesozoic geometries against the pre and post-Alpine trends confirms the structural interference between the mutually perpendicular Triassic–Jurassic extensional structures and the Tertiary compressional ones, this being evident from the regional to the oil-field scale. Despite the model uncertainty, mainly related to its dimension versus the original non-homogeneous dataset quality and distribution, the final geo-volume offers, for the first time in the region, a continuous three-dimensional visualization of the Po Valley tectonic architecture. It provides, simultaneously, a powerful tool for the reviewing of the basin structures and the potential support to future applications for both industry and academia. [Copyright &y& Elsevier]

In thrust belts, fold–fault terminations are common features of the structural architecture and can pose complicated problems to unravel, in particular when two or more terminations are in close proximity. Such terminations usually reflect pre-existing attributes. Amongst the many factors, lateral variations in the mechanical stratigraphy can control along-strike geometry and kinematics of fault-related folds.A displacement transfer zone was produced in a compressional sandbox model by means of two adjacent, mechanically different stratigraphic domains. The experiment allowed two discrete chains to develop in the different domains, so that a complex structural setting occurred in the connecting area. Periclinal folds, oblique thrust fronts and oblique ramps developed in the resulting transfer zone. The interaction between periclines in the transfer zone produced lateral culminations in the folded structures. The analysis of displacement across the structural domains revealed that a significant loss of slip along the faults occurred in the relay zone. In this area, imbricate faulting was partially replaced by layer-parallel shortening. A linear relationship appears to exist between the bed length of the thrust sheet and the related fault slip. [Copyright &y& Elsevier]