Young Uplift at the Eastern End of the Alps. Evidence for Uplift Unrelated to the Inversion of the Pannonian Basin?

2020 ◽  
Author(s):  
Kurt Stüwe ◽  
Gerit Gradwohl ◽  
Thorsten Bertosch ◽  
Konstantin Hohmann ◽  
Jörg Robl ◽  
...  
Keyword(s):  
Pannonian Basin ◽  
Time Frame ◽  
Eastern Alps ◽  
Substantial Part ◽  
Recent Past ◽  
Crustal Shortening ◽  
Surface Uplift ◽  
The Alps ◽  
Uplift History ◽  
Planation Surfaces

<p>The eastern end of the Alps features a series of low relief surfaces at elevations up to 2500 m. These surfaces have long been known to reflect uplifted planation surfaces that have not yet been dissected by fluvial processes and thus preserve a strong geomorphic disequilibrium. While their age would present a good handle on the age of surface uplift in the Eastern Alps, these surfaces are barely dated and their age is only indirectly inferred to reflect the Miocene and Pliocene uplift history. Recent geomorphological cosmogenic nucleide-based studies have shown that these surfaces may record up to 1000 m of surface uplift in the last 5 Ma. Such a distinct uplift event in the recent past is surprising and needs to be interpreted. Interestingly, this time frame appears not to be accompanied by crustal shortening and the standard hypothesis about the inversion of the Pannonian Basin as the underlying cause needs to be questioned. In order to get a better handle on the nature of this young uplift event and its overriding driver it is crucial to understand its spatial extent. However, much of the Eastern Alps was glaciated in the Pleistocene and currently several studies suggest that elevated low-relief landscapes were shaped by the glacial buzz-saw, instead of interpreting them in terms of fluvial prematurity of recently uplifted planation surfaces. The models of glacial erosion versus fluvial prematurity as the formation agent of the low-relief surfaces can be discerned if it can be shown that the surfaces formed prior to the Pleistocene. Here we report of a currently operating research project in which we employ cosmogenic nucleide burial dating on a substantial part of the entire Eastern Alps to derive the age of these surfaces. We use the burial age of siliceous sediments in caves formed at the phreatic-vadose transition as a proxy. Correlation of cave levels with low-relief surfaces and their mapping in the field is an integral part of the project.</p><p> </p>

scholarly journals Evidence for pre-Pleistocene landforms in the Eastern Alps: Geomorphological constraints from the Gurktal Alps

2019 ◽  
Vol 112 (2) ◽  
pp. 84-102 ◽  
Author(s):  
Thorsten Bartosch ◽  
Kurt Stüwe
Keyword(s):  
Power Analysis ◽  
Eastern Alps ◽  
Stream Power ◽  
Main Trunk ◽  
North West ◽  
Surface Uplift ◽  
Geomorphological Map ◽  
The Alps ◽  
Channel Analysis ◽  
Geomorphological Evolution

AbstractWe 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.

scholarly journals Orogenic lithosphere and slabs in the greater Alpine area – interpretations based on teleseismic P-wave tomography

Solid Earth ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 2633-2669 ◽  
Author(s):  
Mark R. Handy ◽  
Stefan M. Schmid ◽  
Marcel Paffrath ◽  
Wolfgang Friederich ◽  
Keyword(s):  
Seismic Anisotropy ◽  
Pannonian Basin ◽  
Lower Boundary ◽  
Eastern Alps ◽  
P Wave ◽  
Moho Depth ◽  
Abrupt Decrease ◽  
Lateral Extrusion ◽  
Wave Tomography ◽  
The Alps

Abstract. Based on recent results of AlpArray, we propose a new model of Alpine collision that involves subduction and detachment of thick (∼ 180 km) European lithosphere. Our approach combines teleseismic P-wave tomography and existing local earthquake tomography (LET), allowing us to image the Alpine slabs and their connections with the overlying orogenic lithosphere at an unprecedented resolution. The images call into question the conventional notion that downward-moving lithosphere and slabs comprise only seismically fast lithosphere. We propose that the European lithosphere is heterogeneous, locally containing layered positive and negative Vp anomalies of up to 5 %–6 %. We attribute this layered heterogeneity to seismic anisotropy and/or compositional differences inherited from the Variscan and pre-Variscan orogenic cycles rather than to thermal anomalies. The lithosphere–asthenosphere boundary (LAB) of the European Plate therefore lies below the conventionally defined seismological LAB. In contrast, the lithosphere of the Adriatic Plate is thinner and has a lower boundary approximately at the base of strong positive Vp anomalies at 100–120 km. Horizontal and vertical tomographic slices reveal that beneath the central and western Alps, the European slab dips steeply to the south and southeast and is only locally still attached to the Alpine lithosphere. However, in the eastern Alps and Carpathians, this slab is completely detached from the orogenic crust and dips steeply to the north to northeast. This along-strike change in attachment coincides with an abrupt decrease in Moho depth below the Tauern Window, the Moho being underlain by a pronounced negative Vp anomaly that reaches eastward into the Pannonian Basin area. This negative Vp anomaly is interpreted as representing hot upwelling asthenosphere that heated the overlying crust, allowing it to accommodate Neogene orogen-parallel lateral extrusion and thinning of the ALCAPA tectonic unit (upper plate crustal edifice of Alps and Carpathians) to the east. A European origin of the northward-dipping, detached slab segment beneath the eastern Alps is likely since its down-dip length matches estimated Tertiary shortening in the eastern Alps accommodated by originally south-dipping subduction of European lithosphere. A slab anomaly beneath the Dinarides is of Adriatic origin and dips to the northeast. There is no evidence that this slab dips beneath the Alps. The slab anomaly beneath the Northern Apennines, also of Adriatic origin, hangs subvertically and is detached from the Apenninic orogenic crust and foreland. Except for its northernmost segment where it locally overlies the southern end of the European slab of the Alps, this slab is clearly separated from the latter by a broad zone of low Vp velocities located south of the Alpine slab beneath the Po Basin. Considered as a whole, the slabs of the Alpine chain are interpreted as highly attenuated, largely detached sheets of continental margin and Alpine Tethyan oceanic lithosphere that locally reach down to a slab graveyard in the mantle transition zone (MTZ).

scholarly journals European tectosphere and slabs beneath the greater Alpine area – Interpretation of mantle structure in the Alps-Apennines-Pannonian region from teleseismic V<sub>p</sub> studies

2021 ◽  
Author(s):  
Mark Handy ◽  
Stefan Schmid ◽  
Marcel Paffrath ◽  
Wolfgang Friederich ◽  
Keyword(s):  
Pannonian Basin ◽  
Lower Boundary ◽  
Eastern Alps ◽  
P Wave ◽  
Moho Depth ◽  
Abrupt Decrease ◽  
Tauern Window ◽  
Lateral Extrusion ◽  
The Alps ◽  
European Plate

Abstract. Based on recent results of AlpArray, we propose a new model of Alpine collision that involves subduction and detachment of thick (180–200 km) European tectosphere. Our approach combines teleseismic P-wave tomography and existing Local Earthquake Tomography (LET) allowing us to image the Alpine slabs and their connections with the overlying orogenic crust at an unprecedented resolution. The images call into question the conventional notion that slabs comprise only seismically fast lithosphere and suggest that the mantle of the downgoing European Plate is heterogeneous, containing both positive and negative Vp anomalies of up to 5–6%. We interpret these as compositional rather than thermal anomalies, inherited from the Variscan and pre-Variscan orogenic cycles. They make up a kinematic entity referred to as tectosphere, which presently dips beneath the Alpine orogenic front. In contrast to the European Plate, the tectosphere of the Adriatic Plate is thinner (100–120 km) and has a lower boundary approximately at the interface between positive and negative Vp anomalies. Horizontal and vertical tomographic slices reveal that beneath the Central and Western Alps, the downgoing European tectospheric slab dips steeply to the S and SE and is only locally still attached to the Alpine crust. However, in the Eastern Alps and Carpathians, the European slab is completely detached from the orogenic crust and dips steeply to the N-NE. This along-strike change in attachment coincides with an abrupt decrease in Moho depth below the Tauern Window, the Moho being underlain by a pronounced negative Vp anomaly that reaches eastward into the Pannonian Basin area. This negative Vp anomaly is interpreted to represent hot upwelling asthenosphere that was instrumental in accommodating Neogene orogen-parallel lateral extrusion of the ALCAPA tectonic unit (upper plate crustal edifice of Alps and Carpathians) to the east. A European origin of the northward-dipping, detached slab segment beneath the Eastern Alps is likely since its imaged down-dip length (300–500 km) matches estimated Tertiary shortening in the Eastern Alps accommodated by south-dipping subduction of European tectosphere. A slab anomaly beneath the Dinarides is of Adriatic origin and dips to the northeast. There is no evidence that this slab dips beneath the Alps. The slab anomaly beneath the northern Apennines, also of Adriatic origin, hangs subvertically and is detached from the Apenninic orogenic crust and foreland. Except for its northernmost segment where it locally overlies the southern end of the European slab of the Alps, this slab is clearly separated from the latter by a broad zone of low Vp velocities located south of the Alpine slab beneath the Po Basin. Considered as a whole, the slabs of the Alpine chain are interpreted as attenuated, largely detached sheets of continental margin and Alpine Tethyan lithosphere that locally reach down to a slab graveyard in the Mantle Transition Zone (MTZ).

scholarly journals Local tectonic deformations measured by extensometer at the eastern foothills of the Alps at the Sopronbánfalva Geodynamic Observatory, Hungary

2019 ◽  
Vol 49 (3) ◽  
pp. 373-390
Author(s):  
Gyula Mentes ◽  
Márta Kiszely
Keyword(s):  
Strain Rate ◽  
Pannonian Basin ◽  
Compressive Strain ◽  
Local Strain ◽  
Eastern Alps ◽  
Local Deformation ◽  
Temporal And Spatial Distribution ◽  
Tectonic Processes ◽  
The Alps ◽  
Local Strain Rate

Abstract In Hungary, at the foot of the Eastern Alps, in the Sopronbánfalva Geodynamic Observatory (SGO), a quartz-tube extensometer has been used for recording the Earth’s tides and local tectonic deformations since 1991. The 27-year long strain record (1991–2017) shows a continuous compression of the rock with changing rate. The relations between the measured local deformation and present-day tectonics in the region of the observatory were investigated. The local strain rate variations were also compared with the temporal and spatial distribution as well as with the magnitudes of earthquakes occurred within 200 km from the observatory in two sectors around the azimuth of the extensometer (116°): 116°±15° and 296°±15°. Our investigations show that earthquakes can also influence the strain rate. Earthquakes to the west of SGO generally increase the compressive strain rate, while earthquakes in the Pannonian Basin, with some exceptions, have no significant effect on the local strain rate variations measured in the SGO. It has been found that the recorded compressive strain is in good accordance with the recent tectonic processes in the region of the SGO determined by Global Navigation Satellite System (GNSS) technology and geophysical measurements. From the results it can be concluded that the uplift of the Alps, tectonic processes in the East Alpine region and in the Pannonian Basin play the most important role in the changing local compressive strain rate.

Microseismicity in the Eastern Alps: Preliminary Results From the Swath-D Network

2021 ◽  
Author(s):  
Rens Hofman ◽  
Joern Kummerow ◽  
Simone Cesca ◽  
Joachim Wassermann ◽  
Thomas Plenefisch ◽  
...  
Keyword(s):  
Large Data ◽  
Eastern Alps ◽  
Detection Methods ◽  
Mountain Range ◽  
Network Methods ◽  
Data Volume ◽  
Geophysical Processes ◽  
The Alps ◽  
Mountain Belts ◽  
Surrounding Areas

&lt;p&gt;The AlpArray seismological experiment is an international and interdisciplinary project to advance our understanding of geophysical processes in the greater Alpine region. The heart of the project consists of a large seismological array that covers the mountain range and its surrounding areas. To understand how the Alps and their neighbouring mountain belts evolved through time, we can only study its current structure and processes. The Eastern Alps are of prime interest since they currently demonstrate the highest crustal deformation rates. A key question is how these surface processes are linked to deeper structures. The Swath-D network is an array of temporary seismological stations complementary to the AlpArray network located in the Eastern Alps. This creates a unique opportunity to investigate high resolution seismicity on a local scale.&lt;/p&gt;&lt;p&gt;In this study, a combination of waveform-based detection methods was used to find small earthquakes in the large data volume of the Swath-D network. Methods were developed to locate the seismic events using semi-automatic picks, and estimate event magnitudes. We present an overview of the methods and workflow, as well as a preliminary overview of the seismicity in the Eastern Alps.&lt;/p&gt;

Review of the Incurvaria vetulella species-group in the Alps (Lepidoptera: Incurvariidae)

1993 ◽  
Vol 24 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Peter Huemer
Keyword(s):  
Eastern Alps ◽  
Species Group ◽  
Female Genitalia ◽  
Male And Female ◽  
The Alps ◽  
Southwestern Alps

AbstractHuemer, P.: Review of the Incurvaria vetulella species-group in the Alps (Lepidoptera: Incurvariidae). Ent. scand. 24: 109-120. Copenhagen, Denmark. April 1993. ISSN 0013-8711. The Incurvaria vetulella species-group in the Alps is defined and reviewed. The following species are recognized: vetulella (Zetterstedt, 1839) (eastern Alps), triglavensis Hauder, 1912 stat. n. (southeastern Alps) and ploessli sp. n. (southwestern Alps). All species are described and/or redefined and adults, male and female genitalia are illustrated. Furthermore, Scandinavian specimens of vetulella and circulella (Zetterstedt, 1839) are illustrated for comparison. The considerable external variation between various alpine populations of vetulella is discussed and regarded as infraspecific. A lectotype of triglavensis is designated.

scholarly journals Environmental factors as drivers for macroinvertebrate and diatom diversity in Alpine lakes: New insights from the Stelvio National Park (Italy)

2019 ◽  
Vol 78 (2) ◽  
Author(s):  
Angela Boggero ◽  
Silvia Zaupa ◽  
Simona Musazzi ◽  
Michela Rogora ◽  
Elzbieta Dumnicka ◽  
...  
Keyword(s):  
High Altitude ◽  
National Park ◽  
Geographical Area ◽  
National Research Council ◽  
Nutrient Content ◽  
Eastern Alps ◽  
High Elevation ◽  
Alpine Lakes ◽  
High Altitude Lakes ◽  
The Alps

Information on the biodiversity of high altitude lakes in the Stelvio National Park was scarce and fragmentary, in most cases limited to a few studies on a single biological issue. To fill this gap, a multidisciplinary research program was established in 2011 to investigate macroinvertebrates, diatoms, and water chemistry in 8 high altitude lakes within the boundaries of the Park (Rhaetian Alps, Eastern Alps). The results of this study were compared with data on biological assemblages and chemical parameters of Alpine lakes in the Pennine-Lepontine Alps (Western Alps), to evaluate the role of local drivers with respect to regional ones. This comparison was possible thanks to the adoption of standardized sampling methodologies developed since the ’90s by the National Research Council-Water Research Institute (Verbania), in collaboration with several European Research centers. Despite located in a restricted geographical area, the lakes of the Stelvio National Park showed a high variability of chemical composition, and of sensitivity to acidification, lower than that of the Pennine-Lepontine Alpine lakes. Macroinvertebrate and diatom taxa were ubiquitous and frequent along the Alps, and mainly represented by cold-stenothermal species. Richness, Shannon, Simpson, and Pielou indices applied to phyto- and zoobenthos highlighted significantly lower values in Stelvio National Park lakes than in those of Pennine-Lepontine for macroinvertebrates, while no significant differences were found for diatoms. Two groups of lakes were identified by Cluster Analysis, mainly on the basis of major ion concentrations. Canonical Correspondence Analysis showed that the macroinvertebrate assemblage of the lakes studied is driven mainly by altitude and lake surface, and, to a lesser extent, by nutrient content. On the contrary, pH and acid-related variables played a secondary role for diatoms, while nutrients and, more in general, ionic content had significant effects on their species composition. Overall, the results of this first investigation showed that the high elevation of these lakes affects their macroinvertebrate assemblages, while their diatom communities are comparable throughout the Alps.

scholarly journals Glaciation's topographic control on Holocene erosion at the eastern edge of the Alps

2016 ◽  
Vol 4 (4) ◽  
pp. 895-909 ◽  
Author(s):  
Jean L. Dixon ◽  
Friedhelm von Blanckenburg ◽  
Kurt Stüwe ◽  
Marcus Christl
Keyword(s):  
Eastern Alps ◽  
European Alps ◽  
Glacial Erosion ◽  
Erosion Rates ◽  
The Alps ◽  
Glacial Processes ◽  
Cosmogenic 10Be ◽  
Topographic Forcing ◽  
Eastern Edge

Abstract. What is the influence of glacial processes in driving erosion and uplift across the European Alps? It has largely been argued that repeated erosion and glaciation sustain isostatic uplift and topography in a decaying orogen. But some parts of the Alps may still be actively uplifting via deep lithospheric processes. We add insight to this debate by isolating the role of post-glacial topographic forcing on erosion rates. To do this, we quantify the topographic signature of past glaciation on millennial-scale erosion rates in previously glaciated and unglaciated catchments at the easternmost edge of the Austrian Alps. Newly measured catchment-wide erosion rates, determined from cosmogenic 10Be in river-borne quartz, correlate with basin relief and mean slope. GIS-derived slope–elevation and slope–area distributions across catchments provide clear topographic indicators of the degree of glacial preconditioning, which further correlates with erosion rates. Erosion rates in the easternmost, non-glaciated basins range from 40 to 150 mm ky−1 and likely reflect underlying tectonic forcings in this region, which have previously been attributed to recent (post 5 Ma) uplift. By contrast, erosion rates in previously glaciated catchments range from 170 to 240 mm ky−1 and reflect the erosional response to local topographic preconditioning by repeated glaciations. Together, these data suggest that Holocene erosion across the Eastern Alps is strongly shaped by the local topography relict from previous glaciations. Broader, landscape-wide forcings, such as the widely debated deep mantle-driven or isostatically driven uplift, result in lesser controls on both topography and erosion rates in this region. Comparing our data to previously published erosion rates across the Alps, we show that post-glacial erosion rates vary across more than 2 orders of magnitude. This high variation in post-glacial erosion may reflect combined effects of direct tectonic and modern climatic forcings but is strongly overprinted by past glacial climate and its topographic legacy.

Denudation history of the French Massif Central: new insights from thermochronology, basement-basin cross-sections and semi-automated planation surfaces mapping

2020 ◽  
Author(s):  
Thomas François ◽  
Guillaume Baby ◽  
Paul Bessin ◽  
Julien Baptiste ◽  
Jocelyn Barbarand ◽  
...  
Keyword(s):  
Cross Sections ◽  
Sedimentary Cover ◽  
Fuzzy Classification ◽  
French Massif Central ◽  
Surface Mapping ◽  
Massif Central ◽  
Planation Surface ◽  
Surface Uplift ◽  
Source To Sink ◽  
Planation Surfaces

&lt;p&gt;Documenting surface uplift of basement areas is challenging, usually due to large gaps in the sedimentary record. In order to address this issue for the French Massif Central, we here investigate its denudation history through an integrated study that involves planation surface mapping, Apatite Fission-Track (AFT) Analysis and basement to basin cross-sections.&lt;/p&gt;&lt;p&gt;First, Planation surfaces were identified using a semi-automated fuzzy classification of pixels based on relationships between DEM derivatives (slope, curvature, ruggedness and incision) and field-recognized training samples.&amp;#160; Then, their different generations and age ranges were discriminated from hypsometry, fault partitioning and relationships with dated sedimentary and/or volcanic remnants, providing constraints on basement exhumation. Afterwards, integrating the previous planation surface analysis, geological cross-sections were produced from the Massif Central basement to the surrounding basins (Aquitaine Basin and Paris Basin). These sections provide local thicknesses estimates of the missing sedimentary cover over basement domains. Theses local thicknesses and exhumation phases were finally used as constraints to produce a thermal history modelling and a denudation map of different areas of the French Massif Central estimated from AFT inversion.&lt;/p&gt;&lt;p&gt;Our results show different burial and exhumation patterns with i) a main burial of its western parts (Limousin, Rouergue) during Jurassic times followed by an important regional denudation (1 to 2 km of missing cover and crystallized basement) during the early Cretaceous and ii) an Upper Cretaceous burial of its northeastern parts (Morvan, Forez) followed by an uppermost Cretaceous to Paleogene exhumation (&lt;1 km of missing cover and crystallized basement). This further illustrates the different behavior of each units of the Massif Central during the Mesozoic to Cenozoic times. These results will ultimately be discussed and placed back into the western European deformation framework.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;(This work is founded and carried out in the framework of the BRGM-TOTAL project Source-to-Sink)&lt;/p&gt;

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