Role of topography in isotherm perturbation: Apatite (U-Th)/He and fission track results from the Malta tunnel, Tauern Window, Austria

摘要: [1] Apatite (U-Th)/He and fission track age determinations of samples from a 20-km-long, near-horizontal tunnel in the Hochalm-Ankogel Dome (eastern Tauern Window, Austria) are presented order to determine role (paleo)-topography perturbing isotherms shallow crust. Apatite ages (26–8 Ma) show no systematic correlation with distance along or elevation. Two components data indicate cooling through ∼120°C at approximately 20 Ma ∼80°C 6 Ma. Surface (17–9 13–5 Ma, respectively) consistently younger than equivalent ages. vary systematically older northern southern portals central section. Geological factors (faulting, lithology) appear have had little effect on this distribution. The pattern is inconsistent rock underneath present-day topography. minimum interpreted coincide paleotopographic maximum suggests that 40–60°C were warped sufficiently affect apatite match synthetic He derived two-dimensional numerical model landscape evolution. Integrating thermal results allows relief development be constrained we calculate topography was formed 7 10