Numerical models of tectonic deformation at the Baltica–Avalonia transition zone during the Paleocene phase of inversion Anna Maria Marotta * , Roberto Sabadini Department of Earth Sciences, Sec. Geophysics, University of Milan, L. Cicognara 7, I-20129 Milan, Italy Received 27 November 2001; accepted 23 September 2002 Abstract Predictions from dynamic modelling of the lithospheric deformation are presented for Northern Europe, where several basins underwent inversion during the Late Cretaceous and Early Cenozoic and contemporary uplift and erosion of sediments occurred. In order to analyse the evolution of the continental lithosphere, the equations for the deformation of a continuum are solved numerically under thin sheet assumption for the lithosphere. The most important stress sources are assumed to be the Late Cretaceous Alpine tectonics; localized rheological heterogeneities can also affect local deformation and stress patterns. Present-day observations available in the studied region and coming from seismic structural interpretations and stress measurements have been used to constrain the model. Our modelling results show that lateral variation in lithospheric strength below the basin systems in Central Europe strongly controls the regional deformation and the stress regime. Furthermore, we have demonstrated that the geometry of the boundary between Baltica and Avalonia, together with different rheological characteristics of the two plates, had a crucial role on local crustal deformation and faulting regime resulting in the Baltica – Avalonia transition zone from the S– N Alpine convergence. D 2003 Elsevier B.V. All rights reserved. Keywords: Tectonic deformation; Baltica–Avalonia transition zone; Paleocene phase of inversion 1. Introduction During the last 20 years, an extensive geological and geophysical database was collected in the area extending from the North Sea to the Mediterranean, in the southern part of Europe. In the 1980s, the Euro- pean Geotraverse Project (EGT, 1990; Blundell et al., 1992) integrated much geological and geophysical information in Europe. This project paved the way to several new European projects during the 1990s, such as the EUROPROBE programme (EUROPROBE, 1996; Blundell, 1999) and one of its major scientific projects, the Trans-European Suture Zone project (TESZ) (Pharaoh, 1999), which enriched the already available database along the Trans European Suture Zone by new seismic experiments (MONA-LISA Working Group, 1997a,b; DEKORP BASIN Research Group, 1998, 1999; Guterch et al., 1999) and the acquisition of new potential field data (Wybraniec et al., 1998). All these new data provided a deeper knowledge of the structure of the crust and the mantle of Europe and encouraged controversial discussions about the origin and the extent of specific crustal structures. The interpretation of new seismic refraction data indicates a high velocity layer in the lower crust 0040-1951/$ - see front matter D 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0040-1951(03)00281-6 * Corresponding author. E-mail address: anna.maria.marotta@unimi.it (A.M. Marotta). www.elsevier.com/locate/tecto Tectonophysics 373 (2003) 25– 37