New whole-rock geochemical and detrital zircon U–Pb and Lu–Hf data of metasedimentary sequences of the Silvretta Nappe, Orobic Alps, Strona-Ceneri Zone, Gotthard Massif and Venediger Nappe are presented. These units seem to share a common early to middle Paleozoic geological record, which has alternatively been interpreted as the result of intraplate or orogenic processes. Detrital zircon data mainly indicate late Ediacaran to early Ordovician maximum sedimentation ages for the studied sequences, suggesting that they were intimately related to Cadomian and Cenerian orogenic processes along the northwestern Gondwana margin. The common presence of late Ediacaran to Cambrian Cadomian ages associated with variable subchondritic to suprachondritic Lu–Hf compositions points to recycling processes of Cadomian sequences, further supported by geochemical data indicating a relatively low to moderate maturity of sedimentary protoliths. The occurrence of Cenerian arc-related intrusions in Austroalpine and South Alpine basement unit points to an arc/back-arc position in the early Paleozoic Cenerian orogen, except for the Strona-Ceneri Zone, which was likely located closer to the forearc region, as indicated by the presence of high-pressure metamorphism. Younger sequences, such as the Landeck Quartz-phyllite, document post-Cenerian sedimentation, whereas those of the Venediger Nappe more likely record the early stages of Variscan subduction, as indicated by Devonian maximum deposition ages.

The lateand post-Variscan magmato-sedimentary evolution is documented in rock associations outcropping in the western Tauern Window. This area marks the southeastern part of the Variscan orogenic belt which evolved into a continental margin during the breakup of Pangea. An extensional regime governed the time span between Late Carboniferous and Middle Jurassic, when post-rift subsidence started and led to widespread flooding in Late Jurassic times.

A review of post-Variscan metasedimentary and metavolcanic successions in the western Tauern Window is presented. U/Pb – datations of zircons in metavolcanic rocks reveal ages between 309 and 280 Ma. Deposition of grey conglomerates and black pelites started before 309 Ma in the northernmost basin of the Tauern, the Riffler-Schönach basin. In the more central Pfitsch-Mörchner basin, the onset of conglomerate sedimentation can be dated into the time span between 293 and 280 Ma. The Pfitsch and Windtal Formations are newly defined. The basins were filled with up to 1 km of mainly continental clastics until Early Triassic. Short marine ingressions in Middle- and Late Triassic times flooded only basinal parts of the area where we suppose a more or less continuous sedimentation until the Late Jurassic. Only the Hochstegen Marble documents a nearly complete submergence in the area of the Tauern Window. In spite of the metamorphic overprint, the tentative interpretations of the sedimentary facies give a reasonable picture and allow correlations to nonmetamorphic areas in South Germany or the External Massifs of Eastern Switzerland.

Transient thermal signals such as Pleistocene surface temperature variations or exhumation of great rock volumes are important for the current thermal regime of the Eastern Alpine crust. In this study transient 1-D forward simulations and an analytical approach were used to estimate the order of magnitude of these effects. A comparison with numerical forward simulations and inverse analyses of steady-state heat conduction yields the following main conclusions with respect to the thermal regime of the Eastern Alps along the TRANSALP profile: (1) The change of surface temperatures in the past affects mainly the uppermost part of the Eastern Alpine crust. It results in a maximum thermal signature of more than −6 K at a depth of 2 km. The deviations from a steady-state temperature gradient and heat flow in the region of the Tauern Window range from 0.3–4 K km−1 and 0–6 mW m−2, respectively, with maximum values at the surface. (2) Exhumation of the Eastern Alpine lithosphere may result in a thermal signature of up to 4 K at a depth of 1 km. The thermal signature increases further with depth to a maximum of approximately 80 K at a depth of 50 km. As the temperature gradient of the exhumation signal is almost zero at the base of the crust, Moho heat flow appears to be not critically perturbed. (3) The combined effect of exhumation and changing surface temperatures at the Tauern Window amounts to less than 15% of the steady-state temperatures at a depth of ∼8 km and to less than 10% at the base of Eastern Alpine root. The corresponding perturbation in heat flow is less than 20% at a depth of 4 km, approaching zero below 40 km.

The TRANSALP consortium, comprising institutions from Italy, Austria and Germany, carried out deep seismic reflection measurements in the Eastern Alps between Munich and Venice in 1998, 1999 and 2001. In order to complement each other in resolution and depth range, the Vibroseis technique was combined with simultaneous explosive source measurements. Additionally, passive cross-line recording provided three-dimensional control and alternative north–south sections. Profits were obtained by the combination of the three methods in sectors or depths where one method alone was less successful.

A combination of petrophysical measurements and inverse modeling is used to estimate the 2-D, steady-state conductive thermal regime in the crust and heat flow at the Moho along the N–S trending TRANSALP profile across the continental collision zone of the Eastern Alps. The uncertainty to which each parameter in the simulation is known beforehand is expressed in terms of its variance, entering a Bayesian parameter estimation scheme. This approach is particularly attractive for geological applications––where often information is available, if only with large uncertainty––because it allows to introduce soft information into a quantitative approach. Our inversion studies show that while the large a priori standard deviation of particularly the heat production rate in the upper crust can be significantly reduced a posteriori, the variance of the middle crust heat production rate remains comparatively large. Using two extreme models with maximum and minimum heat production rates in the middle crust the range of Moho temperatures and heat flow can be estimated. Depending on different assumptions about the composition of the middle crust we obtain maximum temperatures of around 900 °C ± 30% in the lower most parts of the European crust. In the Alpine root and in the Southern Alps, maximum temperatures are 700–800 °C ± 10% and 600 °C ± 10%, respectively. Moho heat flow varies from 5–25 mW m−2 and is largest underneath the European plate and lowest underneath the Alpine root.

A structural and lithostratigraphic study was carried out in the area around the Hochfeiler, Zillertal Alps, southwestern Tauern Window. Strongly deformed sedimentary and orthogenic rocks are sandwiched between the lowermost basement of the Western Tauern Window, the Variscan granitoids of the Zillertal Zentralgneis Core, and the Penninic Glockner Nappe. Mapping in 1 :10.000 scale has shown, that some rocks, previously thought to be of sedimentary origin, in fact belong to the Variscan Zentralgneis. This leads to a new structural model of an early Alpine duplex structure with Zentralgneis- and metasedimentary horses. The duplex above the Zillertal Zentralgneis Core suffered ductile oblate deformation during increasing metamorphic conditions. The whole Hochfeiler area including the Zillertal Zentralgneis experienced later large scale upright folding combined with ductile east-west extension. Early microstructures have been overprinted extensively due to following events. 1. Introduction

In eastern Brazil, Archean and Proterozoic basement suffered remobilization during the “Brasiliano-event” in Lower Paleozoic time. Dextral strike-slip movement at the ductile shear zones of Paraiba do Sul, Rio Negro, Guacui and others separated lozenge-shaped crustal segments up to 100 kilometers in width. The deformation of these segments obviously had been controlled by the shear zones. Contemporaneous large-scale folds with initial wavelengths of about 40 kilometers developed in a charnockitic layer about 10 kilometers thick which had been sheared off from its base. Stretching lineation parallel to the fold axes is typical throughout the whole region. Additionally, a conjugate set of small-scale shear zones enhances this stretching effect.