Terrane accumulation and collapse in central Europe: seismic and rheological constraints

An attempt is made to compare the tectonic units and their evolution in cen tral Europe with the deep seismic velocity structure and patterns of reflec tivity. Caledonian and Variscan terrane accretion and orogenic collapse dom inate the tectonic development in central and western Europe and have left their marks in a distinct velocity structure and crustal thickness as well as in the various reflectivity patterns. Whereas the memory of old collisio nal structures is still preserved in the rigid upper crust, collapse proces ses have formed and modified the lower crust. They have generally created r ejuvenated, thin crusts with shallow Mohos. In the Variscan internides, the center of collision and post-orogenic heat pulses, the lower crust develop ed strong and thick seismic lamellae, the (cooler) externides show a thrust and shear pattern in the whole crust, and the North German Basin experienc ed large mafic intrusions in the lower crust and developed a high-velocity structure with only very thin lamellae on top of the Moho. The various kind s of reflectivity patterns in the lithosphere can be explained by a thermo- theological model from terrane collision, with crustal thickening to collap se in a hot, post-orogenic setting. (C) 1999 Elsevier Science B.V. All righ ts reserved.