Changing patterns of shortening and lateral extension, Exhumation of the Eastern Alpine orogenic core, Strain partitioning during orogenic indentation
Final Report Abstract
Our study reveals that Alpine-type collisional belts grow in three continuous stages: (1) subduction of continental lithosphere leading to stacking of the ocean-continent transition onto distal parts of the downgoing continental margin; (2) nappe stacking and duplex thrusting of proximal members of the downgoing continental margin; (3) indentation of the entire nappe stack by crustal wedges at the leading edge of the upper plate. However our studies also show that lateral orogenic escape in the Eastern Alps is not typical of the rest of the Alps, or of most mountain belts, due to a switch in subduction polarity in Miocene time. This switch involved fragmentation of the indenting Adriatic crust and intracrustal decoupling in the new (European) upper plate; the combination of these events focussed folding and extensional exhumation in the Tauern area. The 4D kinematic view (3D-structure back in time) afforded by this project provides a valuable starting point for advanced seismological and tectonic studies that form the German component of the European AlpArray Project.
Publications
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Grain-size effects on the closure temperature of white mica in a crustal-scale extensional shear zone - implications for dating shearing and cooling from in-situ 40Ar/39Ar laser-ablation of white mica (Tauern Window, Eastern Alps). Tectonophysics 674, 210-226
Scharf A. Handy M.R. Schmid S.M. Sudo M.
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(2013): Modes of orogen-parallel stretching and extensional exhumation in response to microplate indentation and roll-back subduction (Tauern Window, Eastern Alps), International Journal of Earth Sciences 102(6), 1627-1654
Scharf, A., Handy, M.R., Favaro, S., Schmid, S. M., Bertrand, A.
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(2013): Peak-temperature patterns of polyphase metamorphism resulting from accretion, subduction and collision (eastern Tauern Window, European Alps) - a study with Raman microspectroscopy on carbonaceous material (RSCM), Journal of metamorphic Geology, 31(8), 863-880
Scharf, A., Handy, M.R., Ziemann, M.A., Schmid, S.M.
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(2013): The Tauern Window (Eastern Alps Austria): a new tectonic map with cross-sections and a tectonometamorphic synthesis, Swiss Journal of Geosciences 106, 1-32
Schmid, S.M., Scharf, A., Handy, M.R., Rosenberg, C.L.
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(2015): Reconstructing the Alps-Carpathians-Dinarides as a key to understanding switches in subduction polarity slab gaps and surface motion. International Journal of Earth Sciences 104, 1, 1-26
Handy, M.R., Ustaszewski, K., Kissling, E.
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(2015): Transition from orogen-perpendicular to orogen-parallel exhumation and cooling during crustal indentation-key constraints from 147Sm/144Nd and 87Rb/86Sr geochronology (Tauern Window, Alps). Tectonophysics 665, 1-16
Favaro, S., Schuster, R., Handy, M.R., Scharf, A., Pestal, G.
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(2017): Changing patterns of exhumation and denudation in front of an advancing crustal indenter, Tauern Window (Eastern Alps). Tectonics 36,1053-1071
Favaro, S., Handy, M.R., Scharf, A., Schuster, R.
