The erosion history of the Central Alps: evidence from zircon fission track data of the foreland basin sediments

Fission track dating on detrital zircons of Alpine debris in the Swiss mola sse basin provides information about the erosion history of the Central Alp s and the thermal evolution of source terrains, During Oligocene times, onl y sedimentary cover nappes, and Austroalpine basement units were eroded, In cision into Austroalpine basement units is indicated by increasing importan ce of Cretaceous cooling ages in granite pebbles upsection, Erosion of Penn inic basement units started between 25 and 20 Ma, Early Oligocene zircon FT ages show that Penninic basement units were exposed at similar to 20 Ma. D eeper Penninic units of the Lepontine Dome became exposed first at similar to 14 Ma, contemporaneously with the opening of the Tauern window in the Ea stern Alps. A middle Miocene cooling rate of 40 degreesC Myr(-1) is deduced for the Lower Penninic units of the Lepontine Dome.