Seismic studies of Paleozoic orogens in SW Iberia and the Middle Urals

Terrane drift preceding continental collision and the§subsequent mountain building tectonic processes are§derived from paleomagnetic, paleoclimatic, faunal,§geological, petrological and geochemical data.§Geophysical methods are used to study the structure§and physical properties of the modern sub-surface. By§integrating all available data, the origin and§evolution of orogenic belts can be inferred. §Seismic profiles conducted worldwide show that§different crustal provinces (e.g. shield areas,§Caledonian provinces, Variscan provinces, rifts, and§orogens) are characterized by different crustal§structure and velocity profiles. Reflectivity and§velocity structure of the Variscan and Uralian§orogenic belts provided by controlled seismic methods§presented in this book. Although it is assumed that§these structures were formed close in time and at§similar conditions, comparison of the results shows§that the crust of these two orogens looks quite§different at depth.