High to low velocity succession in the upper crust related to tectonic emplacement: Tras os Montes-Galicia (Iberia), Brittany and Limousin (France) |
| |
| Authors: | Alfred Hirn Luisa Senos Martine Sapin Luis Mendes Victor |
| |
| Institution: | Laboratoire d'Etude Géophysique de Structures Profondes, Institut de Physique du Globe, 4 place Jussieu, 75230 Paris cedex 05, France;Institute National de Meteorologia e Geofisica, rua C do Aeroporto, Lisboa, Portugal;Laboratoire d'Etude Géophysique de Structures Profondes, Institut de Physique du Globe, 4 place Jussieu, 75230 Paris cedex 05, France;Instituto National de Meteorologia e Geofisica, rua C do Aeroporto, Lisboa, Portugal and Centro de Geofisica da Universidade, Lisboa, Portugal |
| |
| Abstract: | Summary. Seismic probing of the upper crust in a catazonal massif in Tras os Montes, Hercynian Iberia, demonstrates the absence of a root towards the lower crust and favours a mechanism of thrust and nappe emplacement. Similar high to low velocity successions in the upper crust are evidenced in particular segments of the Hercynian domain of France. All these occurrences are related to a type region to which a particular meaning has been given in a recent plate tectonics interpretation of the Hercynian orogenesis. This model, implying large-scale nappe displacement and intracrustal thrusts furnishes in turn a general mechanism for the tectonic formation of upper crustal high and low velocity layers of limited extent in orogenic cycles. |
| |
| Keywords: | |
|
|
