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The pivotal aim of this research is to identify new entrants to mountain farming, their routes into practicing and resulting environmental impacts. Following an actor-network approach, this multi-regional case study was conducted in two remote regions of the Western Austrian Alps and in a bordering Alpine region in South Tyrol (Italy). All data was generated using semi-structured interviews on site and official agricultural statistics.

We present evidence for a series of pre-Pleistocene landforms on hand of a new geomorphological map for the Gurktal region of the Eastern Alps. The Gurktal Alps region is the westernmost region of the Eastern Alps that escaped the glacial reshaping in the Pleistocene. Its morphology therefore preserves evidence of older landforms in closer proximity to the central part of the range than any other region in the Alps. The region is therefore useful to document aspects of the geomorphological evolution for the Eastern Alps during both, the Pleistocene glaciations and the earlier uplift history. Our mapping approach is twofold. We applied stream-power analysis outside the glacially overprinted areas to detect and classify spatially distinct quasi-stable stream segments, which we expanded to planar objects using slope analysis combined with field mapping. Our mapping results document four palaeo-surfaces located roughly at about 1500 m, 1200 m, 900 m and about 800 m above sea level. We correlate these levels with well-known palaeo-surfaces from the eastern end of the Alps and suggest that they can be interpreted in terms of more than 1000 m of surface uplift in the last six million years. Channel analysis and the distribution of Pleistocene gravel terraces suggest that the main trunk of the river Gurk was diverted from the Wimitz valley in the Rissian. Furthermore, steam-power analysis documents an ongoing activity of the Görschitztal fault and some inferred Pleistocene activity of a north-west trending fault close to the township of Gurk. [ABSTRACT FROM AUTHOR]

Glacigenic perialpine lakes can constitute continuous post-last glacial maximum (LGM) geological archives which allow reconstruction of both lake-specific sedimentological processes and the paleoenvironmental setting of lakes. Lake Mondsee is one among several perialpine lakes in the Salzkammergut, Upper Austria, and has been previously studied in terms of paleoclimate, paleolimnology and (paleo)ecology. However, the full extent and environment of Late Glacial to Holocene sediment deposition had remained unknown, and it was not clear whether previously studied core sections were fully representative of 3D sediment accumulation patterns. In this study, the sedimentary infill of Lake Mondsee was examined via high-resolution seismic reflection survey over a 57-km extent (3.5 kHz pinger source) and a sediment core extracted from the deepest part of the lake, with a continuous length of 13.76 m. In the northern basin, seismic penetration is strongly limited in most areas because of abundant shallow gas (causing acoustic blanking). In the deeper areas, the acoustic signal reaches depths of up to 80 ms TWT (two-way travel time), representing a postglacial sedimentary sequence of at least 60-m thickness. Holocene deposits constitute only the uppermost 11.5 m of the sedimentary succession. Postglacial seismic stratigraphy of Lake Mondsee closely resembles those of well-studied French and Swiss perialpine lakes, with our data showing that most of Lake Mondsee's sedimentary basin infill was deposited within a short time period (between 19,000 BP and 14,500 BP) after the Traun Glacier retreated from the Mondsee area, indicating an average sedimentation rate of about 1.4 cm/yr. Compared to other perialpine lakes, the seismic data from Lake Mondsee reveal little indication of mass movement activities during the Holocene. One exception, however, is rockfalls that originate from a steep cliff, the Kienbergwand, situated on the southern shore of Lake Mondsee, where, in the adjacent part of the lake, seismic profiles show mass transport deposits (MTDs), which extend approximately 450 m from the shore and are mappable over an area of about 45,300 m2. Sediment cores targeting the MTDs show two separate rockfall events. The older event consists of clast-supported angular dolomitic gravels and sands, showing high amounts of fine fraction. The younger event exhibits dolomitic clasts of up to 1.5 cm in diameter, which is mixed within a lacustrine muddy matrix. Radiocarbon dating and correlations with varve-dated sediment cores hint at respective ages of AD 1484 ± 7 for Event 1 and AD 1639 ± 5 for Event 2. As our data show no evidence of larger-scale mass movements affecting Lake Mondsee and its surroundings, we infer that the current-day morphology of the Kienbergwand is the result of infrequent medium-scale rockfalls. [ABSTRACT FROM AUTHOR]

The Salzach Valley is one of the major valleys in the Eastern Alps which was occupied by a large ice stream during glacial maxima. In contrast to the Inn and Enns valleys, dated Pleistocene sediments predating the last glacial maximum are rare in the interior of this valley. The only known site is a former gravel pit near Halldorf, close to the conspicuous turn of the valley, where reworked lignite fragments were previously dated to 32 to 55 ka BP. In this study we re-examined these and additional lignite fragments in order to clarify the chronostratigraphic position of this site. Observations made at the time when the quarry was in operation showed that the lignite fragments were well rounded and compressed, and occurred in poorly sorted and poorly bedded deltaic foresets which lacked evidence of over-consolidation. The lignite also contains wood which is also compressed. Radiocarbon analyses performed on twelve individual wood samples yielded 14 infinite C dates (with one exception) indicating that they were most likely older than the Middle Würmian. Pollen showed high arboreal pollen percentages including Picea (dominant), Alnus, Pinus, as well as low percentages of Quercus, Fagus, Abies and Corylus in some samples. Osmunda was also found in some samples. Wood anatomical studies performed on fourteen samples revealed a dominance of Pinus, which, however, likely reflects the poorer preservation potential of soft wood genera such as Picea. The pollen data confirm the radiocarbon dates and document the former presence of a forest vegetation, consistent with Early Würmian records from the northern alpine rim including Mondsee. Although the pollen data do not permit to unequivocally assign these lignite samples to a known stratigraphic interval, they favour a First Early Würmian Interstadial age, whereby different samples record different parts of this long period during which the former peat bog formed. Strong compaction of the peat and wood probably reflects ice loading during the last glacial maximum, while subsequent erosion, transportation and re-deposition by meltwater streams occurred during the deglaciation phase. [ABSTRACT FROM AUTHOR]

A new model was developed for the paleogeographic distribution of dinoflagellate cysts across the Cretaceous/Paleogene (K/Pg) boundary. Four sections in the Eastern Alps were studied. The Knappengraben and Gamsbach sections are located in the Gosau Basin of Gams, Austria. They are continuous across the boundary and represent a bathyal environment. The Waidach section north of Salzburg (Austria) contains neritic deposits of the Helvetic unit but shows a hiatus at the boundary. The Goppling section between Teisendorf and Oberteisendorf (Bavaria, Germany) belongs to a turbidite-rich, deep-water system (Ultrahelvetic unit), and is considered to be continuous across the boundary. The occurrence and distribution of dinoflagellate cysts in these sections suggests that Trabeculidinium, Adnatosphaeridium, Spiniferites, Pterodinium, Impagidinium, Achomosphaera and Codoniella are restricted to bathyal environments, whereas Areoligera, Manumiella and Trithyrodinium are restricted to the neritic environment. The abundance of Manumiella and Trithyrodinium indicate a high nutrient supply. Hystrichosphaeridium-dominated assemblages have been recorded in both neritic and bathyal environments. Two Manumiella spikes were recorded only at Waidach and interpreted to reflect slight coolings of oceanic surface waters. In the Danian, acme of Spongodinium delitiense are recorded ~1 m above the K/Pg boundary in the neritic and bathyal environments. These acmes could reflect a slight cooling of surface waters in the earliest Danian. The palynofacies analysis in the Gams Basin reveals a high abundance of amorphous organic matter in the Maastrichtian, and black phytoclasts in the Danian, which indicates intensified terrigenous run-off in the Danian with higher sea-floor oxygenation. In the Waidach section, palynomorphs are much more abundant, indicating a shelf to basin transitional area with dysoxic-anoxic conditions at the sea-floor. [ABSTRACT FROM AUTHOR]

In crystalline mountain regions, relict rock glaciers are apparent sediment accumulations that likely influence the runoff in alpine watersheds as a result of their discharge behavior. However, little is known about their impact on the streamflow further downstream. More than 560 mostly relict rock glacier-related landforms have been identified in the Styrian part of the Niedere Tauern Range (Austria). The catchment of a single relict rock glacier (Schöneben Rock Glacier, SRG), and two catchments with relict rock glaciers in their headwaters were investigated with a simple lumped-parameter rainfall-runoff model. The model parameters of the SRG catchment are in agreement with the existing conceptual understanding of the discharge dynamics and provide the parameter configuration to simulate the runoff of ungauged relict rock glacier catchments in the area. In addition, a semi-distributed approachwas applied to quantify the impact of relict rock glacier-influenced headwaters on the downstream runoff. The results suggest that the contribution ranges from about a quarter to more than four times its areal share. The highest impact is observed during the late snow melt period and in the late summer. This highlights the relevance of these sediment accumulations in relation to water management issues, in particular concerning altering meteorological conditions due to climate change. [ABSTRACT FROM AUTHOR]

During the construction of the Brenner Base Tunnel (BBT), on the Austrian project side about 12 million m³ of tunnel excavation material have to be disposed of in landfills, since this material cannot be used as aggregate. Therefore, the Padaster Valley, a side valley of the Wipp Valley, will be filled in with nearly 8 million m? excavation material and with a maximum filling height of about 78 meters. Due to the size of the disposal site and the settlements situated immediately downstream, the geological underground conditions and in particular the hydraulic behaviour of the groundwater body play an important role for the planning and the construction of the disposal site. Based on field data, borehole and pit logging and sampling, geophysical investigations and lab data, a conceptual geological model was established for the complex sediment content of the quaternary infill of the Padaster Valley. Combining above data and the established conceptual geological model, Multiple Point Geostatical Simulation (MPS) was used to derive a quantitative and realistic volumetric representation of the sedimentary infill. It is the basis for the conceptual hydrogeological model of the Padaster Valley. For the design of the groundwater monitoring network of the complex site the elaboration of a hydrogeological conceptual model in the early project phase was essential. We assume several flow systems in the quaternary infill lacking thick or continuous layers in form of aquitards or aquicludes; most of the hydraulic impact is due to fine-grained sediment lenses and layers within the soft rock body. The hydrogeological conceptual model with implications to the groundwater monitoring network in the alpine valley site is discussed. The results of this study shall contribute to a better comprehension of the complex geological conditions and hydrogeological processes in alpine side valleys. [ABSTRACT FROM AUTHOR]

The Vienna Basin Fault System (VBFS) is one of the most seismically active regions of Austria, delineating the southern part of the Vienna Basin. This sinistral, strike slip fault system, accommodates part of the deformation due to the northward push of the Adriatic microplate. In 2000 and 2013, two pairs of main shocks followed by a few tens of aftershocks occurred in the region of Ebreichsdorf, one of the clusters of seismicity along the VBFS. The main shocks seem to be located closely in both cases, even though high-resolution double-difference locations are available only for the sequence in 2013. Focusing on this sequence, we investigate the interactions between the two main shocks and their 18 aftershocks. The two main shocks are located almost at the same place, at a depth of 10.5 km, while the aftershocks constitute a shallower ellipsoid with its long axis parallel to the main trace of the VBFS. We use two Coulomb failure stress models to study possible static stress transfer between the main shocks and the aftershocks of this sequence, the apparent friction model and the isotropic poroelastic model. Both models yield Coulomb failure stress changes below 0.01 MPa at the aftershocks locations. Static stress transfer seems then unlikely to explain their occurrence, even though interactions between aftershocks could play a role in their triggering. Two other mechanisms are considered, namely pore pressure diffusion along an idealized fault plane, and aseismic creep. A high hydraulic diffusivity of about 1-10 m²/s would be however required to account for the spatial extent of the possible interactions (~0.5-1 km) and the inter-event times (hours to days). The shallower location of the aftershocks compared to both main shocks could also point to the migration of fluids toward the surface. The occurrence of collocated events of comparable sizes and focal mechanisms, also named seismic repeaters, is often attributed to the presence of aseismic creep. But without further observations it would be difficult to support or rule out this hypothesis. Either the presence of high pore pressure or aseismic slip has important implications for the presentday earthquake potential of the VBFS to produce large earthquakes. [ABSTRACT FROM AUTHOR]

The central Tauern Window and the adjacent Austroalpine Unit are characterized by complex tectonic, geological and geomorphologic settings that result in a variety of different hillslope processes. Most scientific studies in the literature about slope instabilities in the Tauern Window focus on single slopes only. The present work is a first attempt, to give a regional overview about gravitational mass movements and predispositional factors, which are typical for the Sub-Penninic, Penninic and Austroalpine units. The varying anisotropy in rock material caused by a highly diversified foliation and the presence of brittle fault zones affects the stability of the slopes within the study region significantly, thus leading to spatial pattern of different types of gravitational mass movements. Mountain slope deformations are the most characteristic morphologic feature and occur throughout the study area. The Sub-Penninic and Penninic units show a higher susceptibility of to rockslides and mountain slope deformations in the southwest dipping slopes. The Upper Austroalpine sub-unit is more susceptible to rockfalls in addition to mountain slope deformations. The Lower Austroalpine sub-unit is primarily susceptible to mountain slope deformations, the dominant mechanism being creep. Some areas of the slopes are covered by moraine deposits or scree due to the glacial and postglacial landscape evolution. Rockfall activity, due to the remobilization of boulders caused by erosion processes, mass movements or wind throw, is a common process. Such „secondary" rockfalls can be triggered nearly everywhere in the study area. Superficial soil slips and flows are quiet common gravitational mass movement types in the Quaternary fillings of the steeply incised valleys. [ABSTRACT FROM AUTHOR]

We study the coupling between crust and mantle in a convergent regime, by comparing measures of upper mantle deformation with indicators of crustal deformation. We use shear-wave splitting parameters, in particular the orientation of fast axes in the upper mantle measured from data recorded at 8 broadband stations located within the Tauern Window. These are compared with kinematic indicators in the Tauern Window region of the eastern Alps at the outcrop scale. Our results show a striking parallelism between the upper mantle and crustal patterns, indicating vertical coherence of deformation all the way between the crust and the mantle lithosphere. The new findings suggest a vertical coherence of deformation of crust and upper mantle, particularly in the western part of the Tauern Window. Similar pattern in our results and indentation models indicate that the effect of the Adriatic indentation acts on the European lithosphere, not only at crustal but also at lithospheric mantle depths. We discuss the implication of this vertical coherence for the question of mechanical coupling. [ABSTRACT FROM AUTHOR]

Shear zones are zones of enhanced fluid flow and may act as pathways for mineralizing fluids. The occurrence of talc may be related to such shear zones. Magnesite and talc deposits in the Eastern Greywacke zone were investigated to understand the role of faults to the occurrence of talc. The deposits Veitsch, Wald am Schober and Lassing are of Mg carbonate hostrocks and vary in their talc content. Geochemical analysis, stable isotopes and fluid inclusion studies were performed to yield indications on kind, origin and temperature of the talc mineralizing fluid. The results have shown that the precipitation of talc in the Eastern Greywacke zone is related to increasing deformation and temperature along shear zones. The magnesite deposit of Veitsch is characterized by brittle low temperature deformation features and analyses have demonstrated that fluid temperatures are commonly low (~180°C) similar to samples of host rocks outside the deposits. The magnesite deposit of Wald am Schober contains minor occurrences of talc along discrete shear zones. The deposit is characterized by ductile deformation features. Temperatures of the mineralizing fluids are significantly higher (~250°C). At the former Lassing talc mine talc occurs within large shear zones and yield features of high deformation. All three deposits are in vicinity to fault zones (Mur-Mürz-Fault, Paltental-Liesingtal-Fault, SEMP) that were active during Miocence escape tectonics. In the case of Wald am Schober extensional tectonics following Eo-alpine (Cretaceous) orogeny may have played an important role. The fluids that lead to the precipitation of talc are of metamorphic origin. It can be concluded that major fault zones as well as nappe boundaries have a great impact as fluid pathways and zones of deformation where mineralizations are largely enriched. [ABSTRACT FROM AUTHOR]

The cooling history of the Polinik and Kreuzeck Blocks of the Austroalpine units to the southeast of the Tauern Window are reexamined in the light of new mica Ar/Ar-, zircon fission track and apatite fission track data. Our new data demonstrate that the two blocks experienced a significantly different thermal evolution during Mesozoic-Cenozoic times: The Polinik Block revealed Late Cretaceous Ar/Ar ages (87.2-81.6 Ma), which reflect cooling subsequent to the thermal peak of Eo-Alpine metamorphism. The Kreuzeck Block, in contrast, shows early Permian Ar/Ar ages (295-288 Ma) that reflect post-Variscan extension and cooling. Late Cretaceous zircon fission track ages (67.8 and 67.3 Ma) found in the Kreuzeck Block are interpreted to reflect post-metamorphic exhumational cooling after the Eo-Alpine metamorphism. Miocene apatite fission track ages (21.3-8.7 Ma) and transdimensional inverse thermal history modelling results suggest that the Polinik Block cooled rapidly through the apatite partial annealing zone and exhumed to near surface temperatures in the middle Miocene. The Kreuzeck Block, in contrast, cooled and exhumed to near surface temperatures already in the Oligocene and early Miocene as evidenced by apatite fission track ages (29.1-16.4 Ma) and thermal history modelling results. Based on the temperature difference between the uppermost and lowermost samples from steep elevation profiles, calculated paleo-geothermal gradients are in the range between 47 and 43 °C/km for the late Oligocene and middle Miocene periods. These high values likely resulted from an elevated heat flow associated with magmatism in the area and from the fast exhumation of hot Penninic domains during Oligocene and Miocene times. [ABSTRACT FROM AUTHOR]

N S shortening in front of the Adriatic indenter, surface uplift and exhumation of the Tauern window area characterize the Late Oligocene to recent tectonic evolution of central sectors of the Eastern Alps. The resulting structures are typified by eastward tilted blocks, separated by extensional corridors. The eastward retreat of the subduction zone in front of the Carpathians induced strong Miocene E--W extension and basement subsidence in the Pannonian basin realm; surface uplift in the Tauern window area created E--W topographic and exhumation gradients, allowing the brittle upper crust to move along the mid-crustal ductile decollément level towards the east. Subject of research is the area between the viscous Penninic zone of the eastern Tauern Window and the overlying brittle Austroalpine basement units with deeply eroded/inverted basins on top. We use published apatite fission track (AFT) and apatite and zircon (U-Th)/He (AHe, ZHe) data from two sections of the Hohe Tauern to the east to constrain the E--W exhumation gradient. A W--E section along the southern Northern Calcareous Alps and sections along the Mur-Mürz fault zones are included for comparison, too. Based on AFT, ZHe and AHe data and assuming a thermal gradient of 30 °C/km, a tilt angle of ca. 4° is found similar for both basement sections. This low gradient is close to a gradient typical for viscous material with low shear strength. These relationships imply that a gravitational collapse alone might be sufficient to explain the eastward motion of the brittle Austroalpine crust over a thick viscous Penninic layer. Flow above a low-friction viscous layer also explains the eastward tilting of blocks, including the Saualpe and Koralpe blocks, along ca. N--S antithetic high-angle dextral transtensional faults. The present-day structure east of the Tauern window within the Eastern Alps could be explained, therefore, by intra-orogenic raft tectonics, which represents the motion of an inclined brittle upper layer on a highly ductile, plastically deformed lower layer. [ABSTRACT FROM AUTHOR]

The sedimentary infill of over-deepened alpine valleys and basins in the Eastern Alps are of great interest for groundwater resource management. The internal architecture and geometry of the sedimentary bodies within these valleys is generally complex, resulting in hydrological diverse groundwater systems. The objective of this study has been to model the 3D spatial distribution, sedimentary structures, and hydraulic properties of sediment infill in the Zell Basin of the upper Salzach valley (Austria). The irregular sample - spacing within the area, combined with the presence of highly unpredictable lateral extents of the sedimentary units, rendered 3D modeling of such complex sedimentary sequences a challenging exercise. Several possible geostatistical modeling/simulation approaches to developing realistic subsurface models of the heterogeneous sedimentary infill were investigated. Indicator kriging was found to smooth the spatial variability in stochastic simulations of a particular sediment type, and hence sequential indicator simulation, sequential indicator co-simulation, and multiple point statistics were used instead to simulate the 3D distribution of sedimentary units. Multiple point statistics was found to produce more realistic distributions than the variogram - based simulation methods, with better characterization of the lateral extent of sedimentary units. [ABSTRACT FROM AUTHOR]

Mapping of fault slip data and the consecutive estimation of paleostress orientations are routine procedures during structural geological investigation. In addition, there are various other small- to mesoscale features of brittle deformation which are frequently neither mapped nor routinely used for paleostress analysis. In this paper we present such data, i.e. conjugate shear fractures, faulting related secondary fractures, tensile/extensional fractures, veins, low angle shears and listric faults, from the Koralpe, Eastern Alps. Paleostress orientations are determined with the help of stereographic projection techniques and compared to the results of published fault slip data and fault slip data gathered during tunnelling of the Koralm Tunnel in the Badenian Florianer beds of the western Styrian Basin. The analysed data yield paleostress axes which may be attributed to the three Andersonian fault types with similar orientations as the ones achieved by fault slip analysis. Yet, a reliable (relative) timing of the different tectonic events is not possible on the basis of the structures analysed and time constraints from the surrounding basins are limited to Ottnangium till Sarmatium. Hence, a calibration for possible Paleogene brittle tectonic event(s) is not possible at present. Data attributable to normal faulting can be summarized to three directions of extension (SW-NE, W-E and NNW-SSE). SW-NE directed extension dominates the area near to the Lavanttal fault zone, indicating the opening direction of the Lavanttal Basin. More pronounced scatter of extension direction characterizes the central Koralpe, σ directions indicate W-E, NW-SE and NE-SW extension respectively. W-E directed exten- 3 sion (fluctuating between WSW-ENE and WNW-ESE) dominates the eastern margin towards the Styrian Basin. "Strike slip" data can be summarized to represent two events, with interchanging orientation of the σ and the σ axes. The vicinity of the Lavanttal 1 3 fault zone is characterized by N-S to NW-SE directed compression axis. N-S to NNE-SSW directed σ dominates the central area 1 of the Koralpe. The eastern margin yields predominating W-E to WNW-ESE directed, and single N-S directed σ axes. Moderate 1 reverse faultings in WSW-ENE to WNW-ESE direction is confirmed. Yet similar structures are not known from the Styrian Basin and therefore age constraints are missing. Similarity of σ orientations to some of the strike slip data indicates a relationship to strike 1 slip tectonics. [ABSTRACT FROM AUTHOR]

Montfort hill, lying in Morzg, within the southern outskirts of Salzburg, consists of Upper Cretaceous deposits of the Gosau Group. Alluvial fan deposits of the Kreuzgraben Formation (?Turonian) and Coniacian neritic limestone (Glanegg beds of the Paratexanites serratomarginatus ammonite zone) are overlain by bathyal marlstone ("Morzg beds"). Diverse planktonic assemblages (foraminifera, calcareous nannoplankton and dinoflagellate cysts) indicate that they lie in the upper part of the Dicarinella asymetrica planktonic foraminifera zone and the Lucianorhabdus cayeuxii calcareous nannoplankton zone (CC16 resp. UC12) of the middle to upper Santonian. As in the near-by Untersberg region (Eitelgraben section), the succession at Morzg is punctuated by a stratigraphic gap comprising the lower Santonian and probably parts of the middle Santonian. [ABSTRACT FROM AUTHOR]

For age determination purposes, the luminescence signals from the fine-grained (4-11 μm) quartz and polymineral fractions of samples taken from a Pleistocene palaeolake site in the Eastern Alps of Austria were investigated. Optically stimulated luminescence (standard blue optical luminescence at 125°C (OSL), infrared stimulated luminescence at 50°C (IRSL50/225) and post-infrared stimulated luminescence at 225°C (pIRIR225) were measured and analysed. In order to reveal the potential masking of anomalous fading of the natural signal by incomplete bleaching prior to deposition, anomalous fading and bleaching characteristics were addressed. Anomalous fading tests showed average g-values of <2%/decade for both the IRSL50/225 and pIRIR225 signals. Bleachability, i.e. the rate and extent of natural signal loss during direct exposure to sunlight was derived experimentally. The bleaching experiment showed rapid and thorough bleachability of the OSL and IRSL signals, and a distinctively slower bleaching of the pIRIR225 signal. The comparison of ages calculated from the different measurements shows that both the fading of uncorrected and corrected IRSL ages are consistent within uncertainties with the uncorrected quartz OSL ages. The corrected and uncorrected pIRIR50/225 ages, however, show a large overestimation when compared with the OSL ages. Considering the small fading rates and the relatively poor bleachability of the pIRIR signal225, this may be due to incomplete bleaching. For the IRSL50/225 ages the results suggests that the samples are well bleached and do not suffer from anomalous fading. The results of this study allow to constrain the origin and duration of the Unterangerberg palaeolake to the Middle Würmian (ca. 55 to 40 ka) and hence provide the necessary geochronological framework for environmental and climatic proxy studies of this poorly known time interval prior to the Last Glacial Maximum. [ABSTRACT FROM AUTHOR]

New biostratigraphic investigations based on calcareous nannoplankton and dinoflagellates cysts indicate that the „Walserberg Series“ near Salzburg comprises deposits from the Upper Aptian to the Mid-Campanian. Generally, deposition took place below the CCD. The major part of the sedimentary succession displays no similarities with coeval deposits of the Northern Calcareous Alps, but can be readily correlated with the Rhenodanubian Group of the Penninic Basin (Rehbreingraben Formation, Lower Varicoloured Marlstone, Reiselsberg Formation, Seisenburg Formation, Kalkgraben Formation, Hällritz Formation). Only one outcrop containing glaucophane bearing sandstone cannot be integrated into the Rhenodanubian Group and might be an equivalent of the Branderfleck Formation of the Northern Calcareous Alps. In any case, the term "Walserberg Series" can be abandoned. [ABSTRACT FROM AUTHOR]

Greenschists intercalated within calcareous phyllites of the Western Greywacke zone of the Eastern Alps yield a U-Pb zircon age of 384.5±1.9 Ma enabling dating of the calcareous phyllites at the Middle to Upper Devonian boundary. No such facies has been dated until now in the fossil-bearing respectively low-grade metamorphic Austroalpine basement and we here introduce the term Hochglocker facies for this unit. The Hochglocker facies occurs in the limb of a kilometer-sized ESE-plunging synform, which is mantled by thick dolomites and marbles of assumably Early to Mid Devonian age, and a thick succession of grey phyllites intercalated by greenschists and Silurian graphitic phyllites. At the outcrop-scale, the area is dominated by two stages of ductile deformation structures. The entire area is dominated by penetrative foliation S1 and a gently ESE plunging stretching lineation L1 which formed during Cretaceous low-grade metamorphic conditions. The S1 foliation is refolded by tight upright ESE-plunging D2 folds with a steep WNW-trending axial plane foliation indicating Cretaceous-aged NNE-SSW shortening. [ABSTRACT FROM AUTHOR]

In this study we use a concept based on three geophysical methods (Ground-penetrating radar / GPR, seismic refraction, gravimetry) to provide new insight into the internal structure, ice content and dynamics of the two active rock glaciers Ölgrube and Kaiserberg. Both rock glaciers are located in side valleys of the Kauner Valley (Ötztal Alps, Austria) and consist of debris derived from orthogneiss, paragneiss and mica schist. At both rock glaciers we determined a 4 - 6 m thick debris layer at the surface (active layer), underlain by 20 - 30 m of ice-rich permafrost, and 10 - 15 m of ice-free sediments. The average depth to the bedrock was found in 35 - 50 m. Estimated volumetric ice contents vary between 40 and 60 % based on our field measurements. Structural and physical parameters derived from the mentioned surface based geophysical methods are used to explain the dynamics of the rock glaciers. From the two rock glaciers that were investigated in this study and one additional rock glacier, which was investigated by applying the same methodology in an earlier study, we found a parameter that describes their creep behaviour and shows that the three geophysical models are conclusive. Concerning the dynamics of these active rock glaciers, the data indicate that a reduction of the ice content causes an increase of internal friction, lower seismic P-wave velocities, and higher bulk densities. In order to keep a degrading rock glacier in motion a thickening is required. The GPR-reflection patterns of the permafrost layer and their relation to the structural and physical parameters primarily reveal that long reflectors parallel to the surface are found in regions with high P-wave velocity and low density, indicating zones with high ice content. [ABSTRACT FROM AUTHOR]

Sediments of the Eocene Holzer Formation from the Pemberger quarry were analysed for palynomorphs, lipid biomarker distributions, and clay mineralogy. The palynoflora is rich in megathermal and mesothermal families and genera, but also contain abundant wind-derived pollen derived from temperate to mesothermal taxa. The co-existence of temperate to megathermal elements suggests a sub/tropical and seasonally controlled passat-like or monsoon-like climate, comparable with the extant forests of the zonoecotone I/II, an interpretation consistent with relatively high temperatures derived from soil bacterial glycerol dialkyl glycerol tetraether (GDGT) lipid distributions. The lithologies and palynomorph assemblages represent three different facies: (1) coal-bearing palm swamp characterized by Myricaceae, triporate pollen types, fern spores and several palm pollen types, (2) coastal near swamp with mangrove elements such as Nypa, Avicennia and Ceriops, and (3) shrubby back swamp dominated by Myricaceae, triporate pollen, fern spores and palm pollen types. All of these are consistent with a dominance of terrigenous lipids, including triterpenoids and leaf waxes, in all samples. Abundant kaolinite contents in all the sediment samples are consistent with the biomarker and pollen analyses, indicating long periods with deep weathering under a warm and humid climate. [ABSTRACT FROM AUTHOR]

Several coarse grained metasediment units with preserved primary sedimentary structures were investigated within and in the surroundings of the Penninic Tauern Window. In its NE part - the central area of the study, breccias and conglomerates form elongated lenses a few kilometres in length, composed of multiple layers separated by erosional boundaries. Most of the breccias and conglomerates are matrix-supported, but a few are clast-supported. They were mainly deposited by debris flows and to a lesser extent by high-concentration turbidity currents. Various coarse-grained to fine-grained, thick- to thin-bedded turbiditic sandstones occur west of the breccias. They are interpreted as turbidity current deposits. Some layers are contorted, probably due to syn-sedimentary slumping. The entire organization of the bedforms implies that the coarse-grained sediments represent mainly fault controlled slopea-prons and the more fine-grained sandstones submarine fans, respectively. Black shales and mudstones that separate the breccias, conglomerates and sandstones are regarded as slope and/or base-of-slope to hemipelagic sediments. Additionally, observations from other areas e.g. Penken, Tarntal and Radstadt Mountains, show breccias and conglomerates formed as slope-aprons. Breccias from Richbergkogel display features of both slope-apron and submarine fan. Large elongate blocks of dolomite and limestone cropping out along the northern and southern margins of the Tauern Window were derived mainly from units to the south containing Triassic carbonate platform sediments and represent olistoliths. Our findings suggest that the slope-aprons and the submarine fans were related to the development of the southern margin of the Penninic Ocean and reflect its diachronous opening lasting from Middle Jurassic to Early Cretaceous. Moreover, the mass transport deposits from the Matrei Zone indicate the beginning of the ocean closure which is supposed to have taken place in the late Early Cretaceous. [ABSTRACT FROM AUTHOR]

The newly discovered planktonic foraminifer Hantkenina gohrbandti nov. spec. forms the evolutionary link between the genera Clavigerinella and Hantkenina. This ancestor of the genus Hantkenina is characterized by pointed chamber ends with a nub (prototubulospines) and in some cases by the first tubulospines appearing in a juvenile growth stage. The transition from Clavigerinella caucasica to Hantkenina mexicana is observed in a 2 m thick part of the Middle Eocene Holzhäusl section (Mattsee, Austria) within planktonic foraminifera Zone E8 and calcareous nannoplankton Sub-Zone NP15b. The section was deposited in bathyal water-depths in the northwestern Tethyan realm and is now part of the Ultrahelvetic thrust unit. [ABSTRACT FROM AUTHOR]

In the Kleinelendtal/Ankogel-Hochalm-Group (eastern Tauern Window) pre-Mesozoic units are well preserved. These units comprise Variscan orthogneisses (the Zentralgneise) and their host rocks, the "Pre-Zentralgneis-Complexes" (formerly "Altes Dach"). The "Pre-Zentralgneis-Complexes" comprise the "Zwischenelendschiefer" (biotite-schists, garnet-micaschists and sericite-schists) and amphibolites. Their contacts with the Zentralgneise are mostly concealed by debris- and rock flows or overprinted by shear zones and faults. Preserved primary contacts are rare. Characteristic of the biotite-schists are biotite-blasts of golden colour due to weathering. Besides this biotite, quartz, plagioclase, potassium feldspar, white mica, and chlorite also calcite, garnet, magnetite/ ilmenite, titanite, and zircon are present. Its whole rock analysis shows an intermediate chemism. The calculated initial 87Sr/86Sr(360 Ma) -value of 0.70676 ± 0.000004 and an εNd(360 Ma, CHUR) of -1.8 indicate that considerable amounts of juvenile crust/mantle material have been added to the sedimentary protolith. Detrital zircons from the biotite-schists yield an U/Pb - LA-MC-ICP-MS maximum age of sedimentation of 360 ± 13 Ma for the host sediment, confirming that the "Zwischenelendschiefer" do not date back to pre-Variscan times or even earlier. This suggests a close relationship with the units of the central Tauern Window, i.e. the so-called Biotitporphyroblastenschiefer of the Granatspitz-Group. Garnet-micaschists crop out adjacent to the biotite-schists. Major- and minor constituents are white mica, quartz, chlorite, and garnet; accessory minerals magnetite/ilmenite and titanite. The appearance of sericite-schists is limited to a few outcrops. They are leucocratic crumbly rocks that are made up of sericite, quartz, and biotite. The amphibolites show metamorphic banding and fine-grained mineral contents of hornblende, epidote-group minerals, and plagio- clase, furthermore titanite, rutile, and magnetite/ilmenite. Main- and trace elements shows a basaltic chemism. The initial 87Sr/86Sr(360 Ma) -ratio is 0.70525 ± 0.000004 and the εNd(360 Ma, CHUR) is +5.3. Thus the amphibolites are interpreted to be meta-magmatic. Furthermore also the amphibolites of the Kleinelendtal are geochemically similar to the Basisamphibolit of the central Tauern Window which again proposes a genetic relationship between these units. All lithologies of the Pre-Zentralgneis-Complexes have been overprinted in multiple phases; the latest thermal event was a retrograde greenschist-facies metamorphism which is evident by new growth of chlorites, epidote-group minerals and albite. Due to the Late Devonian maximum sedimentation age of the biotite-schists there is no evidence for the existence of pre-Variscan lithologic units within the Kleinelendtal, contrary to any former interpretations of the regional geology. Thus a position within the Variscan orogenic cycle is proposed for the genesis of some parts of the wall rocks of the Zentralgneise. This is in line with the datingresults of the Basisamphibolit and Biotitporphyroblastenschiefer in the central Tauern Window. [ABSTRACT FROM AUTHOR]

The area extending from the upper Mürz Valley to Semmering, and on to the southern Vienna Basin, belongs to the seismically most active regions in Austria. Because of the population density and sensitive infrastructure, seismic hazard assessment is an important issue. Routine location of earthquakes carried out by the Central Institute for Meteorology and Geodynamics, Austria, images well the general seismicity pattern. However, a correlation with individual faults cannot be resolved. In this study, recordings from passive seismic monitoring projects (ALPASS and CBP) and permanent seismic network data are used together with a new 3D seismic velocity model to locate earthquake hypocentres in the Vienna Basin area. Three different location methods were applied. Focal coordinates of the 44 earthquakes determined by these methods depend on the applied method and differ considerably from the routine locations. Analysis of the residual travel-times and the location of quarry blasts showed that the best results were achieved with a probabilistic location method based on the new 3D velocity model for P- and S waves. An absolute accuracy of ~3 km was obtained by this method. Clustering and linear alignment of epicentres as well as their probability density functions allow for the correlation with local fault systems. Hypocentres with increasing focal depth closely follow the Mur-Mürz in the Semmering area and its extension to the Pottendorf fault in the southern Vienna Basin. Further, the continuation of the Salzach-Ennstal-Mariazell- Puchberg fault towards the Vienna Basin has been imaged clearly by epicentres. Implementation and further improvement of the 3D velocity model has the potential to enhance accuracy of routine epicentre location. [ABSTRACT FROM AUTHOR]

The Kimmeridgian to Tithonian Wolfgangsee Carbonate Platform as the northernmost platform of the Plassen Carbonate Platform sensu lato (s.l.) in the Northern Calcareous Alps was drowned in the Late Tithonian. The pre-drowning phase (Early Kimmeridgian to early Late Tithonian), the drowning phase and the post-drowning phase (both Late Tithonian) are preserved at Mount Bürgl. The A) drowning event of the northern Wolfgangsee Carbonate Platform, the B) formation of a north-directed newly formed reef rim of the Plassen Carbonate Platform sensu stricto (s.s.) as well as the C) onset of resedimentation of enormous amounts of shallow-water debris from the central Plassen Carbonate Platform (s.s.) to the north, the D) enhanced subsidence with a prominent facies change at the Plassen Carbonate Platform (s.s.), and E) Tithonian normal faulting in the central Northern Calcareous Alps are more or less time-equivalent events. With respect to A)-E) we explain the Late Tithonian drowning of the Wolfgangsee Carbonate Platform as a result of the change in the overall tectonic regime: the compressional regime lasted until Late Oxfordian followed by a period of decreasing tectonic activity and relative tectonic quiescence in Kimmeridgian to Early Tithonian, and a subsequent extensional tectonic regime, that started around the Early/Late Tithonian boundary being responsible for the changes A) to E). The generally accepted model of a Kimmeridgian to early Early Cretaceous phase of tectonic quiescence during the evolution of the Plassen Carbonate Platform (s.l.), which formed a post-tectonic cover, must be replaced by a model of both diachronous platform onset and diachronous drowning in an active tectonic regime. [ABSTRACT FROM AUTHOR]

A ca. 320 m thick composite section (Goppling section) of a turbidite-rich deep-water system outcropping between Teisendorf and Oberteisendorf (Bavaria) encompasses the upper Maastrichtian to Ypresian (calcareous nannoplankton Zones CC25 to NP11). These deposits conformably overlie red clayey marlstone (Buntmergelserie). The whole succession is part of the Ultrahelvetic thrust unit, which is a detached part of the continental margin of the southern European Plate. In the latest Maastrichtian and early Paleogene, subsidence to below the calcite compensation depth coeval with the onset of turbidite sedimentation indicates the development of slope-basins by subsiding crustal fault blocks. These basins acted as sediment traps and caused a dearth of turbidite sedimentation in the adjoining Penninic basin. During the Danian, turbidites in the Goppling slope-basin were deposited from currents, that flowed parallel with the E-W-trending basin axis and the strike of the slope. In the Selandian, sedimentation rates outpaced subsidence rates and the basin filled up to the spill-point. This is indicated by a shift in the section from sand-rich to mud-rich lithologies and a change from basin-axial to downslope (N-S) paleotransport directions. Turbidites were deposited on the smooth bathymetry of the filled basin due to the reduction of slope gradient. Another pulse of subsidence formed a new depression at this site in the Ypresian and caused the deposition of a sand-rich turbidite succession from longitudinal flowing turbidity currents. For the entire deep-water system overlying the Buntmergelserie, the new lithostratigraphic term Achthal Formation is introduced. [ABSTRACT FROM AUTHOR]

Recent large-scale seismic experiments extended and refined existing crustal models of the Eastern Alps and their surrounding geologic provinces considerably. However, areas of low resolution and ambiguous interpretation still remain. The integration of gravity data has the potential to further constrain the seismic models of the crustal structure. In this study we concentrate on the gravity effect of the upper crust (max. depth 10 km). We apply gravity stripping of the upper crust and investigate its impact on resolution of deeper structures, especially the Moho-discontinuity. We derive one density model from a data set of sampled densities, and two others from relations between seismic velocity and density. Data from the exploration industry are implemented to determine the densities of Tertiary basins. We calculate the reduced gravity effects of these three models and their corresponding stripped Bouguer gravities. An analysis of the logarithmic power spectrum of the Bouguer anomaly reveals that wavenumbers greater than k = 2π/92 km-1 correspond to sources within the upper crust. We apply this wavenumber as a cut-off to separate the Bouguer anomaly, the reduced gravity effect, and the stripped Bouguer anomalies into high and low wavenumber parts. None of the three density models implemented in gravity stripping reduce the high wavenumber part of the Bouguer anomaly. However, we find that long wavelength density variations dominate the reduced gravity effect of the upper crust. Gravity stripping based on density models derived from seismic data significantly enhances the main structural features, which can be identified in the Moho depth map and are compatible with a lower crust - upper mantle density contrast of ∼ 300 kg/m³. [ABSTRACT FROM AUTHOR]

Two textbook examples of rock-slope failure (RSF) by deep-seated toppling show the importance of pre-existing Alpine tectonic structures, e.g. strike-slip faults, for toppling formation, and document specific geomorphological and rock mechanical conditions at the toe and at the flanks as a prerequisite for the preservation of toppling structures. The study area is dominated by micaschist and paragneiß and situated in Eastern Tyrol northwest of Lienz, close to a major NWSE trending strike-slip fault. The upper slope is characterised by a saw-tooth morphology due to a series of up to 1.5 km long antislope scarps with an upslope trend towards lower dip (80° to 45°) and with up to 300 m wide graben structures in the topmost part. The pattern of these linear structures shows a striking similarity with that of the vertically oriented brittle structures (faults) linked to the major fault system. These features together with the hydrological regime (no surface flow, location of the springs) indicate a deepseated gravitational slope deformation (DGSD). A bulging toe, typical for the RSF of sackung (sagging) as defined by Zischinsky (1966, 1969), is absent. Kinematic analyses according to Goodman and Bray (1976) demonstrate toppling as the only plausible RSF mechanism due to interlayer- slip along this set of discontinuities (faults and joints). Flexural toppling is inferred to be the dominant mode of RSF, whereas the block-flexural mode is apparent in the topmost area where discontinuities have been rotated beyond the limit of flexural toppling. The observed rock disintegration with open joints can be described as the result of an initial collapse along the existing discontinuities. Glacial over-steepening during the Last Glacial Maximum (LGM) followed by the loß of support in the early Lateglacial phase of ice-decay most probably caused the onset of the RSF. At present day, the maß-movements towards the main valley seem to have ceased due to a self-stabilizing effect of the flexural-toppling mode at the lower part of the DGSD. In addition (secondary) rock creep along the flanks, especially in the area of the heavily disintegrated graben structures towards the tributary valleys, may also have had a major impact on slope stability due to the reduction of load in the topmost part. This unloading at the flanks in combination with the orientation of the croß-joint system (re-activated foliation gently dipping into the slope), which prevent a downward slip, and the absence of fluvial erosion at the toe, caused the preservation of these rare toppling structures. A transition from toppling to sackung (Poisel, 1998), the major RSF in crystalline rocks in Alpine valleys, did not occur in these cases. However, as a strictly structure-controlled proceß, toppling is regarded as a significant initial phase of RSF development. Thus, its impact on valley shaping and landscape evolution especially in the longitudinal valleys of the Alps appears to be underestimated. [ABSTRACT FROM AUTHOR]

The Apuseni Mountains were formed during Late Cretaceous convergence between the Tisia and the Dacia microplates as part of the Alpine orogen. The mountain range comprises a sedimentary succession similar to the Gosau Group of the Eastern Alps. This work focuses on the sedimentological and geodynamic evolution of the Gosau basin of the Apuseni Mts. and attempts a direct comparison to the relatively well studied Gosau Group deposits of the Eastern Alps. By analyzing the Upper Cretaceous Gosau sediments and the surrounding geological units, we were able to add critical evidence for reconstructing the Late Mesozoic to Paleogene geodynamic evolution of the Apuseni Mountains. Nannoplankton investigations show that Gosau sedimentation started diachronously after Late Turonian times. The burial history indicates low subsidence rates during deposition of the terrestrial and shallow marine Lower Gosau Subgroup and increased subsidence rates during the period of deep marine Upper Gosau Subgroup sedimentation. The Gosau Group of the Apuseni Mountains was deposited in a forearc basin supplied with sedimentary material from an obducted forearc region and the crystalline hinterland, as reflected by heavy mineral and paleocurrent analysis. Zircon fission track age populations show no fluctuation of exhumation rates in the surrounding geological units, which served as source areas for the detrital material, whereas increased exhumation at the K/Pg boundary can be proven by thermal modeling on apatite fission track data. Synchronously to the Gosau sedimentation, deep marine turbidites were deposited in the deep-sea trench basin formed by the subduction of the Transylvanian Ocean. The similarities to the Gosau occurrences of the Eastern Alps lead to direct correlation with the Alpine paleogeographic evolution and to the assumption that a continuous ocean basin (South Penninic - Transylvanian Ocean Basin) was consumed until Late Cretaceous times. [ABSTRACT FROM AUTHOR]

The paper focuses on modelling the development of the orogen-parallel fault-controlled overdeepened Upper Enns Valley, Eastern Alps. A decrease in relief in the Middle Miocene, an increasing relief from Pliocene to recent times and the interplay between tectonically controlled differential uplift and denudation resulted in a morphology that is reflected by planation surfaces on valley slopes at elevations of about 1100 m. The Upper Enns Valley separates the crystalline basement of the Niedere Tauern in the south from the Greywacke Zone and the Northern Calcareous Alps in the north. The Upper Pleistocene Ramsau Conglomerate covers the Greywacke Zone on the northern valley slope and is suggested to have important information for reconstruct the history of overdeepening of the Upper Enns Valley in several steps. The formation of the Enns Valley started in Early to Middle Miocene and continued to recent times. Valley formation occurred under uplift along the ENE-trending, orogen-parallel transtensional Salzach-Enns strike-slip zone. The southern block suffered a much higher exhumation than the northern block. We interpret the asymmetric drainage pattern, with short northern tributaries to the Enns Valley and long southern ones, to indicate northward tilting of the entire region. Furthermore, Quaternary processes, such as uplift and cyclic glaciations, interfered with neotectonic activity. The provenance of the Upper Pleistocene Ramsau Conglomerate from the southern side of the valley and the presence of a terrace at 1100 m indicates that the Enns Valley was filled from the present base at ca. 820 m above sea level up to that elevation during Late Pleistocene times. Post-Ramsau Conglomerate glacial overdeepening scoured the Enns Valley and resulted in epigenetic and regressive incision of southern tributaries. The channels of the southern tributaries have knick zones, reflecting gradient changes between flat and steep reaches. The suggested continuity of the southern planation surfaces and the top of the Ramsau Conglomerate (at ca. 1100 m) is interpreted to represent a relic former valley bottom. Although close to the Salzach-Enns fault, pronounced knick zones along southern tributaries are interpreted to result from glacial overdeepening rather than from neotectonic activity. [ABSTRACT FROM AUTHOR]

All gravity data acquired in Austria during the past 50 years by different institutions have been reprocessed and homogenized in order to compile a new and accurate Bouguer gravity map of the Eastern Alps. Reprocessing was based on modern methods of terrain correction procedures and a digital terrain model (DTM) with 50 m spacing in order to get accurate corrections even in rough and mountainous areas. The DTM and digital cadastre also helped correcting the station coordinates that had been extracted from topographic maps in some of the early surveys. The final data set consists of 54000 stations with an average station distance of less than 3 km, even in the mountains. Commonly, the Bouguer gravity is based on orthometric rather than on ellipsoidal heights. Based on the newest geoid models, the Bouguer anomaly for the new map was determined using ellipsoidal heights, and the geophysical indirect effect was estimated. Additionally, mass corrections were determined by applying a 2D density model in order to investigate the errors introduced by assuming constant density in the standard processing. Finally, a stripped gravity map was derived to enhance the effect of sources within the upper crust. The new homogenized gravity data set refers to the absolute gravity datum and provides a much improved base for present and future Austrian Geoid solutions in Austria and neighbouring countries. This paper covers collection and processing of gravity data in Austria and presents a new Bouguer gravity map. Results of geological interpretation will be subject of future papers. [ABSTRACT FROM AUTHOR]

Red days from Cenozoic palaeosols of the Eastern Alps record periods of stagnating uplift and decrease of relief. Tropical to sub-tropical weathering of a crystalline substratum formed dominant or abundant kaolinite, reflecting Paleogene and Early Miocene conditions, respectively. Abundant illite and chlorite, but a lack of kaolinite in red clays on the plateaus of the Northern Calcareous Alps reflects feldspar-poor compositions of the Cenozoic siliciclastic cover. The presence of high Ba/Sr and Rb/Sr ratios and vermiculite in these red clays indicates high precipitation and temperate weathering conditions, respectively, during the Late Miocene and Early Pliocene on the uplifting plateaus of the Northern Calcareous Alps. [ABSTRACT FROM AUTHOR]

In the Tithonian Lofer unit (Northern Calcareous Alps, Austria), Heterodiceras shell beds accumulated ahead of a low-energy gravelly beach. This is the first detailed description of diceratid shell beds from the Northern Calcareous Alps. In the Eastern Alps, during Late Jurassic tectonic deformation, parts of structurally highest preserved thrust nappes became islands. During the following latest Jurassic transgression over vegetated land, a variegated succession of shore zone to shallow neritic lithologies accumulated. Near the village Lofer, the transgressive succession records a low-energy gravelly beach ahead of a shallow subtidal, protected bay or lagoon with a bottom of organic-rich, argillaceous lime mud. The proximal area of the bay/lagoon received abundant phytoclasts and clay from land. On organic-rich lime-muddy substrata that may have supported fleshy algal meadows, the larger textulariine foraminifer Anchispirocyclina thrived. Seaward, level-bottoms dominated by the rudist Heterodiceras or by milleporidian hydrozoans were present. The milleporidian banks interfingered with storm spillover lobes shed from oolite dunes farther offshore. The Heterodiceras beds consist of floatstones to rudstones of toppled, disoriented shells in highly different taphonomic states, as a result of episodic toppling and reworking by high-energy events, burrowing, bioerosion, and in-situ shell disintegration. The matrix of lime mudstone to bioclastic wackestone is characterized by terebratulacean brachiopods and microgastropods. While the brachiopods thrived as suspension feeders attached on toppled shells of dead rudists, the microgastropods perhaps scavenged on microbial biofilms and/or on fine-grained dead particulate organic matter. A few of the diceratid shells are variably overgrown by sessile textulariine foraminifera, by microblalites, by milleporidians, and by the microproblematica Lithocodium and Bacinella. The majority of the diceratids had been largely to completely stripped of their thin calcitic outer shell layer. Spelling of the calcitic layer took place early, when the shells were exposed on the sea floor, and during shallow burial within soft sediment. Effective spalling probably was associated with decomposition of organics embedded between the aragonitic, inner shell layer and the calcitic, outer layer. [ABSTRACT FROM AUTHOR]

This study examines the magnetic properties of rocks in a north-south traverse through the area of the western Tauern Window from the Northern Calcareous Alps to the southern rim of the Tauern Window. In the course of the petrophysical investigations about 4500 in-situ susceptibility measurements and laboratory measurements from 167 specimens were taken covering the main tectonic and lithologic units along the traverse. The distributions and the median values of magnetic susceptibilities for different rock types in different tectonic units are presented. From the data it becomes clear that an unambiguous discrimination of different tectonic units based on magnetic properties of similar lithologies is not possible. Besides these petrophysical investigations, 3D models of the magnetic susceptibilities explaining the anomalies of the earths total magnetic field in the areas of W örgl and southern Zillertal were calculated and geologically interpreted. The source rocks of the magnetic anomalies are predominantly serpentinites, locally also metagabbros and metavolcanics. In both cases there are a number of relatively small source rock bodies, which are situated at or very near the surface. The maximum depth extent of the source rocks below the surface is 1200 m for the anomaly W örgl, and 1600 m for the anomaly southern Zillertal respectively. [ABSTRACT FROM AUTHOR]

A single seismogonic layer-model is used for simulating focal depths-distributions for distinct regions of the Eastern Alps in Austria. Prior to this approach, macroseismic data are investigated in terms of slightly wrong intensity assignments, which might be the cause of secondary - hence artificial - peaks in those depth-distributions. This effect can cause a distortion - here referred to as a 'mirror-effect' - of the focal-depth distribution, leading to questionable average focal depths and standard deviations. Considering this effect and the practice of macroseismic data treatment and analysis during the past, it is possible in many cases to simulate focal distributions which match the observed distributions in a satisfactory manner by using a single seismogenic layer, which allows to estimate a maximum magnitude for that particular region. Most earthquakes in the Eastern Alps seem to originate at a depth of 7 ks. Two exemptions - a region in the province of Salzburg and an area around 'Pregarten' in Upper Austria - are noteworthy, however. The latter region was already known for very shallow earthquakes at around 3 km depth, whereas the 'Hagengebirge' region in Salzburg seems to be a region, where deeper earthquakes (10 km) tend to occur. Maximum magnitudes - using a scaling law based on the thickness of this seismic active layer - in the Eastern Alps are also estimated. In most regions below latitude of 47.5° and west of the Styrian Basin, an additional 1 km thin seismic active layer is necessary to explain the observed pattern of focal-depth distributions deduced from macroseismic data. For further macroseismic investigations, the reader is encouraged to report earthquake experiences to www.zamg.ac./bebenmeldung to improve the assessment of local effects in Austria. [ABSTRACT FROM AUTHOR]

Results of dating of datrital white mica using the conventional 40- 39Ar, conventional 40Ar/39Ar multi-grain and laser-probe eAr/UAr multi-grain and single-grain methods contribute significantly to the unraveling of the palaeogeographic origin and tectonic evolution of the Eastern Alps since Late Ordovician times. Dating of Upper Ordovician and Silurian successions of Austroalpine and South-alpine domains consistently demonstrate a Panafrican/Cademian source of these successions, and therefore an origin along nor- thern margins of Gondwana. The source region significantly changed in Lower to lowermost Upper Carboniferous Variscan flysch successions when Gondwana collided with Laurussia. The Lower Carboniferous flysch mostly contains Devonian detritus from units, which are largely unknown in the present erosional level of the Eastern Alps. In contrast, Upper Carboniferous molasse, and Permian and Triassic rift and shelf successions nearly exclusively contain Variscan detritus of Carboniferous age. These Carboniferous ages of the molasse indicate that upper crustal levels with pre-Variscan age signatures have been largely removed prior to molasse deposition. Beside dominant Variscan and Permian ages, subordinate Early-Middle Jurassic ages of detrital white mica within the Florianikogel Formation, a Middle Jurassic flysch succession originating within the Meliata ocean, support the idea that the Meliata oceanic seaway underwent Jurassic subduction. In contrast, only Veriscan respectively Permian ages have been found up to now in the Lower Cretaceous Losenstein-, Branderfleck- and Rossfeld formations. These units ere considered to represent a trench-fill in front of the accreting Austroalpine nappe stack, which partly underwent late Early Cretaceous metamorphic overprint. In the subsequent Upper Cretaceous collapse basins (Gosau basins), K-Ar ages indicate the presence of a variable proportion of Cretaceous-aged low-to medium-grade metamorphic units in the source region. The Lower Cretaceous to Eocene Rhenodanubian Rysch basin is characterized by mainly Variscan ages, although some Upper Cretaceous levels are rich in Cretaceous-aged white mica, similarly suggesting a source in the Austroalpine nappe complex. In the North-Alpine Molasse basin, detritus with Variscan, Permian and Cretaceous ages is dominant and considered to derive from the Austroalpine nappe stack. Oligocene mica ages indicating exposure of Oligocene metamorphic rocks of Penninic units in the Tauern window were only found in the uppermost, Neogene stratigraphic levels of the Molasse basin. Although dose to the Tauern window, exclusively Cretaceous-aged detritus is found in the intramontane, fault-bounded Wagrain basin. This supports the idea of large (>40 km) sinistral strike-slip displacement along the confining Salzach-Enns fault. [ABSTRACT FROM AUTHOR]