The Tauern Window (Eastern Alps, Austria): a new tectonic map, with cross-sections and a tectonometamorphic synthesis

Abstract

We present a tectonic map of the Tauern Window and surrounding units (Eastern Alps, Austria), combined with a series of crustal-scale cross-sections parallel and perpendicular to the Alpine orogen. This compilation, largely based on literature data and completed by own investigations, reveals that the present-day structure of the Tauern Window is primarily characterized by a crustal-scale duplex, the Venediger Duplex (Venediger Nappe system), formed during the Oligocene, and overprinted by doming and lateral extrusion during the Miocene. This severe Miocene overprint was most probably triggered by the indentation of the Southalpine Units east of the Giudicarie Belt, initiating at 23-21 Ma and linked to a lithosphere-scale reorganization of the geometry of mantle slabs. A kinematic reconstruction shows that accretion of European lithosphere and oceanic domains to the Adriatic (Austroalpine) upper plate, accompanied by highpressure overprint of some of the units of the Tauern Window, has a long history, starting in Turonian time (around 90 Ma) and culminating in Lutetian to Bartonian time (45-37 Ma).

Crystallographic preferred orientations of exhumed subduction channel rocks from the Eclogite Zone of the Tauern Window (Eastern Alps, Austria), and implications on rock elastic anisotropies at great depths

“…Figure 1: Tectonic maps of A) the Alps, B) the Tauern Windom (after Schmid et al, 2013) and C) the Eclogite Zone (after Neufeld et al, 2008). The location of the field area is indicated by a frame.…”

Correlated crustal and mantle deformation in the Tauern Window, Eastern Alps

“…This general structure of the nappe system within the Tauern Window was previously described by Kurz at al. ( , 1998, and recompiled by Schmid et al (2013). The present-day architecture of the Tauern Window is primarily characterized by a crustalscale late Alpine duplex, the Venediger Duplex (or Venediger Nappe System) that formed during the Oligocene.…”

“…These indicate NNE-to NNW-directed kinematics during nappe detachment ( Fig. 1), being related to the formation of the Venediger Duplex Kurz et al, 1998;Schmid et al, 2013), with a general overview of kinematics of nappe stacking and shearing contemporaneous to amphibolite to greenschist facies metamorphism (Tauern crystallization), including kinematic data (after Neubauer et al, 1999). Nappe-stacking-related kinematics was reconstructed from maps and field data (for summary, see , and references therein).…”

“…The Tauern Window is characterized by a complex three-dimensional geometry of tectonic units, including important along-strike changes in its structure . This geometry, as described by Schmid et al (2013) by combining surface geology with the results of deep seismic reflection measurements (Gebrande et al, 2002;Lü-schen et al, 2006), basically resulted from crustal-scale collisional accretion in the Alps followed by late-Alpine indentation, crustal-scale folding, orogen-parallel extension and lateral extrusion (Ratschbacher et al, 1991a).…”

Geology of the Brenner Pass-Fortezza transect, Italian Eastern Alps

“…The mapped area and surroundings (Figures 1 and 2) include two main structural domains with contrasting tectonic and metamorphic features: the Austroalpine-Penninic collisional wedge and the Southalpine basement (Bigi, Castellarin, Coli, Dal Piaz, Sartori, Scandone, & Vai, 1990;Bistacchi et al, 2004;Castellarin, Nicolich, Fantoni, Cantelli, Sella, & Selli, 2006;Dal Piaz, 2010;Frisch, Dunkl, & Kuhlemann, 2000;Kummerow, Kind, Oncken, Giese, Ryberg, Wylegalla, Scherbaum, & TRANSALP Working Group, 2004;Kurz, Neubauer, Genser, & Dachs, 1998;Lammerer, Gebrande, Lüschen, & Vesela, 2008;Lammerer & Weger, 1998;Lüschen et al, 2004;Schmid, Scharf, Handy, & Rosenberg, 2013). The former is characterized by a generally pervasive Alpine reworking through subductionrelated blueschist and/or Barrovian greenschist to amphibolite facies metamorphism (Oberhänsli, Bousquet, Engi, Goffé, Gosso, Handy, et al, 2004, and refs.…”