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The DAV and Periadriatic fault systems in the Eastern Alps south of the Tauern window

Mancktelow, Neil ; Stöckli, Daniel ; Grollimund, Balz ; Müller, Wolfgang ; Fügenschuh, Bernhard ; Viola, Giulio ; Seward, Diane ; Villa, Igor

In: International Journal of Earth Sciences, 2001, vol. 90, no. 3, p. 593-622

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    Title
    • The DAV and Periadriatic fault systems in the Eastern Alps south of the Tauern window
    Author
    • Mancktelow, Neil. Department of Earth Sciences, ETH-Zentrum, 8092 Zurich, Switzerland, Switzerland
    • Stöckli, Daniel. Division of Geological and Planetary Sciences, Mail Stop 100-23, California Institute of Technology, Pasadena, CA 91125, USA, USA
    • Grollimund, Balz. Department of Geophysics, Stanford University, Stanford CA94305, USA, USA
    • Müller, Wolfgang. Department of Earth Sciences, ETH-Zentrum, 8092 Zurich, Switzerland, Switzerland
    • Fügenschuh, Bernhard. Geologisch-Paläontologisches Institut, Universität Basel, Bernoullistrasse 32, 4056 Basel, Switzerland, Switzerland
    • Viola, Giulio. Department of Earth Sciences, ETH-Zentrum, 8092 Zurich, Switzerland, Switzerland
    • Seward, Diane. Department of Earth Sciences, ETH-Zentrum, 8092 Zurich, Switzerland, Switzerland
    • Villa, Igor. Mineralogisch-Petrographisches Institut, Universität Bern, Baltzerstrasse 1, 3012 Bern, Switzerland, Switzerland
    Document Type
    • Postprint
    Language
    • English
    Published in
    • International Journal of Earth Sciences, 2001, vol. 90, no. 3, p. 593-622. Springer Berlin Heidelberg
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:318264
    Summary
    Alpine deformation of Austroalpine units south of the Tauern window is dominated by two kinematic regimes. Prior to intrusion of the main Periadriatic plutons at ~30Ma, the shear sense was sinistral in the current orientation, with a minor north-side-up component. Sinistral shearing locally overprints contact metamorphic porphyroblasts and early Periadriatic dykes. Direct Rb-Sr dating of microsampled synkinematic muscovite gave ages in the range 33-30Ma, whereas pseudotachylyte locally crosscutting the mylonitic foliation gave an interpreted 40Ar-39Ar age of ~46Ma. The transition from sinistral to dextral (transpressive) kinematics related to the Periadriatic fault occurred rapidly, between solidification of the earlier dykes and of the main plutons. Subsequent brittle-ductile to brittle faults are compatible with N-S to NNW-SSE shortening and orogen-parallel extension. Antithetic Riedel shears are distinguished from the previous sinistral fabric by their fine-grained quartz microstructures, with local pseudotachylyte formation. One such pseudotachylyte from Speikboden gave a 40Ar-39Ar age of 20Ma, consistent with pseudotachylyte ages related to the Periadriatic fault. The magnitude of dextral offset on the Periadriatic fault cannot be directly estimated. However, the jump in zircon and apatite fission-track ages establishes that the relative vertical displacement was ~4-5km since 24Ma, and that movement continued until at least 13Ma