Apatite fission-track analysis of Neogene exhumation in northern Corsica (France)

Apatite fission-track analyses along a W-E-orientated transect across north ern Corsica indicate an important episode of crustal exhumation in late ear ly Miocene time. Samples taken from the Alpine orogenic wedge, from the adj acent foreland basin and from the crystalline basement complex flooring the basin are completely reset. This implies that a greater than or equal to 2 .0-2.3-km-thick crustal section made of thrust sheets and/or autochthonous foreland deposits has been removed by erosion since early Miocene time. A g eometric projection of this lost cover towards the west indicates that all of northern Corsica was covered either by Alpine nappes or middle Eocene fo reland deposits. Fission-track ages are the same across the main boundary f ault system separating the Alpine orogenic wedge and the foreland, indicati ng the absence of significant differential vertical displacement between up per and lower plates during Neogene unroofing.