THIN-SKINNED PLATE TECTONICS DURING NEO-ALPINE OROGENESIS

Palinspastic reconstructions of crustal structure under the Swiss Alps were made for Late Eocene, middle Miocene, early Pliocene, and Holocene. The reconstructions depict the evolution of the crustal structure during the Neo-Alpine deformation, which took place after continental collision in Eocene. The reconstructions assume underthrusting of successive crustal wedges (not lithospheric plate) and decollement overthrusts of sedimentary covers in the Helvetic Alps and the Jura Mountains. Geological data placed isostatic, kinematic, and petrologic constraints to limit the freedom of choices in the reconstructions. The model of Neo-Alpine deformation is consistent with the fact that no Benioff zone of seismicity is present under the Alps.