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Field Trip E3
Two Orogens and their Subduction Records in the Eastern Alps
|Departure:||Thursday 1 Sep. 08:00||LMU Geology building, main entrance,
Luisenstr. 37, München
|Return:||Sunday 4 Sep. ~18:00|
|Cost:||€ 440; Maximum: 24 participants|
|Not included:||lunch, dinner, drinks|
||USA Class 2. USA National Parks Rating: Moderate.
Bergwanderung mittelschwer / Moderate mountain hike
Bernhard Fügenschuh, University of Innsbruck
Mark Handy, Freie Universität Berlin
|The marbles of the Hohe Weisse and Lodner peaks in the Texel national park show Cretaceous metamorphic overprint and intense polyphase folding. View from Zieltal towards north.|
The Alps comprise two orogens that are exposed in piggy-back fashion in the Eastern Alps. These orogens preserve different relics of subduction: (1) In the overlying Austroalpine nappes Cretaceous eclogites record E- to SE-directed, intracrustal subduction within the Adriatic/Apulian microplate that preceded Alpine orogenesis. This early subduction was probably related to (possibly triggered by?) Jurassic subduction and obduction of the northern branch of the Neotethys Ocean; (2) In underlying units of the Tauern Window, Early Cenozoic eclogite and blueschist document later S- to SSE-directed subduction of the Alpine Tethys Ocean and distal parts of the European continental margin. This later subduction was continuous with Europe-Adria collision and Alpine orogenesis in Oligo-Miocene time.
The first part of this field trip will be devoted to the tectonometamorphic evolution of the Ötztal continental basement and its neighboring Austroalpine units. HP metamorphism was followed by Late Cretaceous nappe stacking, exhumation and amphibolite-facies regional metamorphism. In the second part of the field trip we will visit the Cenozoic HP rocks of the Tauern Window that derive from Alpine Tethys (Glockner Nappe) and from distal European continental crust (Eclogite Zone, Rote Wand unit). In addition, we will show how collisional structures modified the entire nappe edifice in the eastern part of the Tauern Window. We will visit spectacular km-scale folds and shear zone systems that accommodated N-S shortening and east-directed lateral escape. This late orogenic deformation in the Eastern Alps manifests the response of the crust to a combination of Adriatic indentation and Miocene roll-back subduction in the Carpathians.