According to new
apatite fission track, zircon- and
apatite (
U-Th)/He data, we constrain the near-s
urface history of the so
utheastern Ta
uern Window and adjacent A
ustrolapine
units. The m
ulti-system thermochronological data demonstrate that age-elevation correlations may lead to false implications abo
ut exh
umation and cooling in the
upper cr
ust. We s
uggest that isothermal warping in the Penninic
units that are in the position of a footwall, is d
ue to
uplift, erosion and the b
uild
up of topography. Additionally we propose that exh
umation rates in the Penninic
units did not increase d
uring the Middle Miocene, th
us d
uring the time of lateral extr
usion. In contrast, exh
umation rates of the A
ustroalpine hangingwall did increase from the Paleogene to the Neogene and the isotherms in this
unit were not warped. The new zircon (U-Th)/He ages as well as zircon fission track ages from the literat
ure doc
ument a Middle Miocene exh
umation p
ulse which correlates with a period of enhanced sediment acc
um
ulation d
uring that time. However, enhanced sedimentation- and exh
umation rates at the Miocene/Pliocene bo
undary, as observed in the Western- and Central Alps, cannot be observed in the Eastern Alps. This contradicts a climatic trigger for s
urface
uplift, and makes a tectonic trigger and/or deep-seated mechanism more obvio
us to explain s
urface
uplift in the Eastern Alps.
In combination with already published geochronological ages, our new data demonstrate Oligocene to Late Miocene fault activity along the M枚ll valley fault that constitutes a major shear zone in the Eastern Alps. In this context we suggest a geometrical and temporal relationship of the Katschberg-, Polinik-M枚ll valley- and Mur-M眉rz faults that define the extruding wedge in the eastern part of the Eastern Alps. Equal deformation- and fission track cooling ages along the Katschberg-Brenner- and Simplon normal faults demonstrate overall Middle Miocene extension in the whole alpine arc.