Vienna basin
The Vienna Basin is a fossil, geologically young tectonic invasion basin and sedimentary basin in the seam area between the Alps , Carpathians and the Pannonian Plain . With regard to the intrusion mechanism, it is a shear basin ( pull-apart basin ). Although it separates the Alps from the Western Carpathians topographically , it connects them geologically via corresponding rocks in the subsurface.
physical geography
General
The Vienna Basin has a spindle-shaped or diamond-shaped floor plan with a lengthwise extension (southwest-northeast) of 200 km and a transverse extension (northwest-southeast) of a maximum of 50 km. In the natural structure of Lower Austria, the name Vienna Basin only refers to the roughly triangular morphological basin south of the Danube ("Southern Vienna Basin") and the Marchfeld ("Northern Vienna Basin"). These two lowlands occupy parts of the districts of Mödling , Baden , Bruck an der Leitha , Korneuburg , Neunkirchen and Wiener Neustadt .
Taking geological aspects into account, this also includes the hill country of the eastern Weinviertel , the Lower Moravian Basin in the Czech Republic and the Záhorie lowlands in Slovakia .
Natural structure
Overview
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Austria
- Vienna basin in the narrower sense
- Northern Vienna Basin (Marchfeld, mountain range 1930 or 1931 according to Trimmel )
- Southern Vienna Basin (Wiener Neustädter Bucht, mountain range 1920 or 1921 according to Trimmel)
- Humid plain (northern part)
- Dry plain (= stone field , southern part)
- Eastern Weinviertel
- Vienna basin in the narrower sense
- Czech Republic
- Lower Moravian Basin ( Dolnomoravský úval )
- Slovakia
- Zahorian Plain ( Záhorská nížina )
- Bor lowlands ( Borská nížina )
- Chvojnica hill country (Chvojnická pahorkatina)
- Zahorian Plain ( Záhorská nížina )
Vienna Basin north of the Danube
This part of the basin is the larger and morphologically more varied. In Austria it is mainly taken from Marchfeld and the hill country of the eastern Weinviertel . The topographically inconspicuous west and north-west border of the Vienna Basin north of the Danube is formed there by the Leiser Mountains , some isolated limestone cliffs, such as the Staatzer Klippe or the Falkenstein , and the Pollauer Mountains (already in the Czech Republic). These small mountain ranges and mountains are the morphological expression of the Waschberg Zone , a rock belt that is often only a few kilometers wide and connects the Eastern Alps with the Western Carpathians above ground and thus delimits the Vienna Basin geologically to the northwest from the Molasse Basin of the Eastern Alps and the Western Carpathians.
The flat part of the basin to the northeast is called the Lower Moravian Basin . It extends into the Thaya and March lowlands of Moravia and Slovakia and is bounded to the north-west and north by the foothills of the Western Carpathians Steinitz Forest , Martian Mountains and Wisowitz Mountains , the former being geologically the northeastern continuation of the Waschberg zone, the so-called Ždánice unit, heard. The eastern border runs at the foot of the White and Little Carpathians . The z. The partially hilly parts of the basin in Slovakia east of the Marchtal are summarized under the term Záhorie .
Vienna Basin south of the Danube
This part of the basin is divided into the so-called wet plain in the north and the dry plain in the south, also known as the stone field .
The clearest border of this southern part of the basin is the thermal line in the west, where the foothills of the Alps ( Flysch - Wienerwald ) drop relatively steeply by 200 to 300 meters into the plain (altitude 150 to 200 m above sea level ) and even the Limestone Alps by up to 1000 meters in altitude. This line remains clearly visible as far as Vienna, crosses the Danube in the northwest of the city at the Wiener Pforte and runs out northeast of the Bisamberg (Weinviertel).
In the east and southeast, the southern Vienna Basin is delimited from the Pannonian Plain by a chain of mountain ridges . The names of the ridges and the passages in between are, from north to south: Hungarian Gate , Hundsheimer Berge , Brucker Gate , Leithagebirge , Ödenburger Gate and Rosaliengebirge . Since its ridge line does not run roughly northeast-southwest, like that of the other mountain ranges mentioned, but rather describes an arc from northeast to southeast, the Rosaliengebirge is only partially involved in the border of the southern Vienna basin. In addition, the Ödenburger Pforte does not form a direct passage to the Pannonian Plain, but leads into the Eisenstadt Basin , the southwestern border of which is formed by the southeastern part of the Rosaliengebirge. In the extreme southwest, where the Vienna Basin is already very narrow and rises towards the Alps, it is bordered to the east by the Bucklige Welt and to the south by the Semmering area.
Vegetation and climate
The Vienna Basin forms the westernmost part of the Eurasian steppe belt , a very extensive vegetation zone .
economy
Austria
Agriculture still predominates in the east , with mainly grain and sugar beet being grown. But here, too, the structural change is noticeable, for example the sugar factories in Bruck an der Leitha and Siegendorf were shut down. An oil mill for biodiesel was built in place of the sugar factory in Bruck and the farmers are increasingly focusing on the cultivation of rapeseed and sunflowers .
The clay deposits gave rise to the first industry in the form of brickwork south of Vienna at the end of the 19th century . The history of brick production by Wienerberger AG began on the southern edge of Vienna, on Wienerberg . During this time, many immigrants from the crown lands came to the Vienna Basin. These are still colloquially referred to as Brick Bohemia or Brick Behm . As a result of the brickworks, many brick ponds were created, some of which have been placed under nature protection today or are used as bathing ponds. Most of the brick ponds were filled in again in the course of the industrial settlement in the second half of the 20th century.
In economic terms, the northern part of Wiener Neustädter Bucht (Feuchte Ebene), which is part of the area around Vienna, is one of the economically strongest regions in Austria. The Mödling district has the highest per capita tax revenue in Austria. Worth mentioning here is the largest industrial area of Eco Plus , the industrial center Niederösterreich Süd (IZ NÖ-Süd) , which extends over the municipal areas Wiener Neudorf , Biedermannsdorf , Guntramsdorf and Laxenburg as well as the Shopping City Süd (SCS) in Vösendorf. But Vienna-Schwechat Airport with the economy around it is also a growth engine. With the exception of Wiener Neustadt , which only caught up economically later, areas were industrialized very early thanks to the hydropower of Schwechat , Triesting and Piesting, mainly by textile companies. Many companies had to go through major problems due to structural change. This also applies to former flagship companies such as Semperit AG in Traiskirchen , for example . Today, many people have to commute to Vienna. Occasionally, however, new businesses such as Magna International with the European headquarters in Oberwaltersdorf or the equestrian park in Ebreichsdorf are settled.
In terms of transport, the area was opened up very early on. Old Roman roads are already known and the Bernsteinstrasse led through the Vienna Basin. In modern times, railways were built here early on. Today, around 10 railway lines starting from Vienna, 5 motorways through the plain and around 20 federal highways connect the region's transport hubs.
On the thermal line, which acts as a weather divide, there has been viticulture since Roman times ; the wine towns of Sooss and Gumpoldskirchen are located here .
In the southern part, the so-called stone field, the soil is very barren due to ice-age gravel deposits and the so-called snow mountain wind from the west blows the few centimeters of fertile soil. Therefore, under Maria Theresa, they began to plant black pine forests, on the one hand to gain resin for pitching and on the other hand to fortify the soil.
Problems are partly caused by the garbage dumps set up in the wake of the wave of industrialization in the period after the Second World War , such as the Fischer dump , which slowly releases its pollutants, especially hydrocarbons , into the groundwater. With expensive renovations, mostly carried out by the public sector, the groundwater resources in the eastern part, the so-called Mitterndorfer Senke , are made usable again as drinking water . These deposits can also supply the city of Vienna with water in addition to the Vienna high spring water pipes. But other local water networks such as that of Mödling or the Triestingtaler Wasserleitungsverband have additional sources here.
geology
General
In geomorphology, the Vienna Basin is a prime example of a tectonic basin. Structurally, it is a shear basin (pull-apart basin), i. That is, around a stretched crust area in a leaf displacement system , and the Vienna Basin is also exemplary for this type of basin. The reason for the formation of these leaf shifts was the fact that the northern movement of the Alps in the upper Lower Miocene ( Carpathian ) largely came to a standstill, while the Carpathian Mountains moved further north.
The basement of the Vienna Basin is formed by sunken Alpine-Carpathian ceilings . It thus represents the connection between the Eastern Alps and the Western Carpathians and is largely identical to the exposed pre-tertiary rocks of the peripheral mountains of the Vienna Basin. The Eastern Alps put this to the Penninic associated Rhenodanubian flysch and the Austro Alpin calculated Northern Limestone Alps , the greywacke zone and the central alpine units . The Western Carpathians are involved in the basement of the Vienna Basin with the Waschberg-Ždánice unit, which is part of the Ultrasilicon (in a way a counterpart of the Helveticum of the Alps), with the Magura flysch (counterpart of the Rhenodanubian flysch), the units of the central (resp. Inner) Western Carpathians (including the Tatrides) and the Pieninian cliff belt. These allochthonous units lie with tectonic contact on autochthonous Mesozoic and Palaeogenic sedimentary rocks , which in turn are superimposed on the submerged varistics of the "southeast slope" of the Bohemian Massif, but to a small extent in the late phase of the formation of the Carpathians were still recorded by the Alpine tectonics of the Waschberg-Ždánice- Unit were incorporated.
The up to 5500 meters thick neogene sediment filling of the basin has a density of 2.0 g / cm³ on the surface and is compacted at a depth of 5 km by the load to about 2.5 g / cm³. The basement has a specific density between 2.6 and 2.8 g / cm³. The resulting density contrast of 0.4 to 0.8 g / cm³ was investigated early on with gravimetric methods, but also with seismic and vertical deviations . Because at depths of around 500 to 4000 m there are large quantities of crude oil and natural gas that have been extracted since the 1930s and from which Austria still meets over 10% of its needs.
As a sedimentary basin, the Vienna Basin belongs to the central Paratethys paleogeographically . The Paratethys, a primeval sea that still exists today in the shape of the Black and Caspian Sea (eastern Paratethys), which goes back to the Mesozoic Tethys Ocean , covered large areas of south-eastern Europe in the Tertiary, with foothills as far as what is now southern Germany (western Paratethys).
Pelvic development and stratigraphy
Piggyback phase
The Vienna Basin had a forerunner in the Middle Lower Miocene ( Eggenburgian and Ottnangian ). This “Proto-Viennese Basin” was a relatively shallow, east-west running depression that slowly sank into the surface of the alpine blanket pile while it was still moving northward. In such a case, one speaks of a backpack basin (piggyback basin). Sediments of the piggyback phase are only known from the northern and central parts of today's Vienna Basin. The earliest deposits are represented in the northern part by the fluvial sediments of the Stráže formation. As a result of a collapse of the Molasse Sea from the north, they are covered over a large area by the marine siliciclastic deposits (" Schlier ") of the Lužice layers.
The Bockfließ formation, which can be found further south in today's central Vienna Basin and is characterized by brackish tidal sediments, is at least in its deeper part still placed in the Ottnangium.
Pull apart phase
The development of the actual Vienna Basin, i.e. H. the formation of the pull-apart basin began after the northward movement of the Alps in the Carpathian Mountains (late Lower Miocene) around 17 million years ago. The sustained northward movement of the Carpathians led to the formation of a sinistral blade displacement system in the Eastern Alps and Western Carpathians, with faults running approximately northeast-southwest. At the “hinge point” of this movement, the crust of the Alps-Carpathian chain was greatly stretched by the shear forces , so that, based on the leaf movements, almost north-south oriented faults arose, and a rhombus-shaped basin began to sink. Significant such deportation systems include a. the Leopoldsdorfer Bruch , which runs through Vienna, and the Steinbergbruch in the northern part of the basin. While the subsidence at the edges of the basin was only up to 2 km, the central regions of the Vienna Basin subsided by a total of 5.5 km in 9 million years, which corresponds to an average subsidence rate of 0.6 mm per year.
The basin was filled with large amounts of sediment throughout the Miocene, with the predominantly clastic deposits originating from the erosion of the surrounding highlands. In the Carpathian Mountains, the basin filling is mostly formed from terrestrial river and lake as well as marginal river delta deposits (Bock River Formation, Gänsendorf Formation, Aderklaa Formation, Šaštín Sands), but in the northern part of the basin mainly from siliciclastic marine deposits (Závod -Formation and Lakšáry- or Lakšárska-Nová-Ves-Formation - these Schlier sequences were previously summarized under the name "Laaer layers", but according to the stratigraphic table of Austria 2004, this name is now only on marine rocks of the Carpathian Mountains of the Waschberg Zone and the Molasse basin ).
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| Paleogeography of Southeast Europe in the Carpathian and Badenian regions. The red circle marks the location of the Vienna basin. Note that the Ur-Danube drains westward over the Rhone Trench into the Mediterranean. |
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The Karpatian- Badenian turning point , which at the same time corresponds to the turning point from the Lower to the Middle Miocene, is represented by a very pronounced layer gap as a result of a drop in sea level, which is characterized by erosion of the sub-Miocene layers down to the basement in high palaeos. Deposits mainly took the form of fluvial conglomerates (e.g. Aderklaa conglomerate, Jablonica conglomerate). After the sea level rises again in the further course of the Badenium, the marine character of the basin is, however, much more pronounced than in the Carpathian. The sea level was sometimes so high that z. B. the Leithagebirge was completely flooded. In the region of the Leithagebirge, which at the time was relatively remote from the coast but was characterized by very shallow sea depths, the entry of clastic sediments was very low, which is why extensive carbonate deposits and especially reef limestone could arise there, which are known as "Leithakalk". It consists of hard corals , but mainly of calcareous red algae , so-called coralline red algae or Corallinaceae . Accordingly, alternative names for the Leithakalk are Corallinaceenkalk or, according to a special Corallinacekalk, also Lithothamnium -alk . The first description of a fossil coralline red alga in the history of paleontology was made in 1847 using a specimen from the Leitha limestone. A clastic sediment of the areas not covered by the sea on the southern western edge of the basin is the Baden or Vöslau conglomerate. This river sediment contains pebbles that originate from the limestone Alps and the flysch zone. The Baden deposits of greater water depths are represented by sandy-marl-clayey deposits, which are referred to as "Badener Tegel" (Baden Group). Overall, they are very rich in fossils and were deposited at a depth of no more than 200 meters. The relatively shallow sea depth despite the relatively high subsidence rates reflects the high sedimentation rates in the Vienna Basin, i. H. the relief created by the lowering was largely compensated for more or less simultaneously.
The sedimentation conditions and with them the rock associations of the Sarmatian (late Middle Miocene) do not differ for the most part from those of the Badenian. However, the fossils contained show that the salt content of the sea was lower than in the Badenium: there are fewer species, but they are represented with a greater number of individuals. These include a. the snail Pirenella (formerly Cerithium ) and the mussel Cerastoderma . The decrease in salinity is presumably related to an increasing isolation of the central Paratethys from the open ocean by uplifting the Alpine mountain ranges of the Balkans with humid climatic conditions at the same time. In the course of the transgression following a drop in sea level at the Baden-Sarmat border, among other things, the Baden Leithakalk is processed into "detritic Leithakalk".
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| Paleogeography of Southeastern Europe in the Pannonian. The red circle marks the location of the Vienna basin. The central Paratethys has changed from a marine to a lacustrine depository. |
In the Pannonian , the Vienna Basin is finally silted up with initially still brackish (including Tegel) and then limnic-fluvial sedimentation. The prehistoric lake from which these deposits originate is known as the Pannonian lake and the fluvial sediments go back to the activity of the primeval Danube, which formed a tributary of the Pannonian lake. The Pannonian sediments carry large amounts of flaps remains of the zebra mussel genus Congeria , which is why they are also called "Congerien layers". The fluvial gravel that u. a. Widespread in the Weinviertel are mammal fossils, especially the ancient horse Hippotherium . Lignite seams also show clear silting tendencies, which occur mainly in the south of the basin and which may be. are to be placed in the Pontium (most recent Miocene).
Inversion and uplift phase
In the recent Miocene, the tension in the European crust changed. The originally sinistral blade displacements in the basement of the Vienna Basin assume a dextral shear sense, the expansion and thus the subsidence stop and turn into compression and uplift (so-called pelvic inversion). These events actually mark the end of the Vienna Basin as a sedimentary basin. Marine Miocene sediments are now exposed at altitudes of 300 to 400 meters, which, after deducting the eustatic sea level drop since their deposition, suggests an uplift amount of 200 to 300 meters.
Pliocene and Quaternary Dilation
Another change in the stress regime in the course of the Pliocene causes a renewed crust expansion analogous to the processes of the pull-apart phase. However, this young stretch is less strong and causes little subsidence. The post-Miocene sedimentation is therefore locally restricted (e.g. to the so-called Mitterndorfer Basin in the southwestern tip of the Vienna Basin) and no longer reaches the extent of the Miocene sediment accumulation by far.
Importance of neotectonics
The tectonic movements continue to this day. This leads to around three to four noticeable earthquakes per year , especially in the southernmost area of the basin around Wiener Neustadt, especially in the north-eastern continuation of the Mur-Mürz fault zone (south-eastern basin edge) and on the so-called thermal line (western basin edge). Stronger earthquakes only occur every 20 to 30 years. The thermal line is a pool edge fault that owes its name to the thermal waters that come to light there. Therefore there are numerous bathing and health resorts there , e.g. B. Baden , Bad Vöslau , Oberlaa and Bad Fischau . But there are also thermal springs on the southeast edge of the basin, for example in Bad Deutsch-Altenburg and Bad Sauerbrunn .
Satellite basin
Korneuburg Basin
The Korneuburg Basin is a small, narrow (20 × 5 km), NNE-SSW-striking pull-apart basin in the northern continuation of the Vienna Woods near the western edge of the Austrian part of the Vienna Basin. It is named after the small town of Korneuburg in the south of the basin. Geologically, the basin is framed to the north and west by the Waschberg zone and south and east by the flysch zone, and both units also form the basement. The maximum sediment thickness of around 880 meters is significantly less than in the Vienna Basin. The sedimentation took place exclusively in the early Miocene and mainly in the Carpathian. There was no direct connection to the Vienna Basin at the time. Instead, the Korneuburg Basin was connected to the north with the western Paratethys. Accordingly, mainly estuarine sediments are found in the south of the basin and shallow marine deposits in the north.
Eisenstadt-Sopron basin
The approximately triangular, about 20 km wide Eisenstadt-Sopron basin borders on the east of the south-eastern section of the Austrian part of the Vienna basin. It is named after the cities of Eisenstadt in Austria and Sopron (Ödenburg) in Hungary. The basin is framed by the Leithagebirge with the Eisenstadt Fault in the north as well as by the Rosaliengebirge and the Ödenburg Mountains in the southwest and south, which also demarcate it from the Styrian Basin . To the west it is connected to the Vienna Basin via the Ödenburg Gate, to the east it is separated from the Pannonian Basin and the Danube Basin by the low Rust-Fertőrákos Mountains with the Kőhida Fault. At 1500 meters, the maximum sediment thickness is significantly less than in the Vienna Basin.
The oldest sediments of the Eisenstadt-Sopron basin are fluvial-lacustrine deposits of the early Miocene age. They are probably deposits of the same early Miocene river system that produced the same old and similar sediments in the southern Vienna Basin, and the Leithagebirge did not yet exist as a geographical barrier. An individualization of the Eisenstadt-Sopron basin from the actual Vienna basin probably took place in the Badenium. Facially , the Baden and Sarmatian deposits are very similar to those of the Vienna Basin, especially during the high sea levels, with u. a. Leithakalk in the late Badenium. Like the Vienna Basin, the Eisenstadt-Sopron Basin silted up in the Pannon.
literature
- Werner E. Piller, Kurt Decker, Margit Haas: Sedimentology and basin dynamics of the Vienna basin. Excursion guide Sediment '96. 11th Sedimentologentreffen, Vienna 1996 ( PDF 6 MB).
- Mathias Harzhauser, Michal Kováč, Reinhard Roetzel: Vienna Basin and its satellite basins. Pp. 1060-1063 in Tom McCann (Ed.): Geology of Central Europe. Volume 2: Mesozoic and Cenozoic. Geological Society of London, 2008, ISBN 978-1-86239-265-6 .
Individual evidence
- ↑ a b Natural spatial structure of Lower Austria according to M. Fink and T. Wrbka, 1989.
- ^ The subgroup 1931 Marchfeld is the only one in the subgroup 1930 Marchfeld ; In a revised version of the mountain group structure, however, the Marchfeld no longer belongs to the main group 1900 Vienna Woods, Vienna Basin and Alpine Foreland east of the Traisen , but bears the mountain group number 6848 as part of the main group 6800 Bohemian Massif and Carpathian Foreland and the subgroup 6840 Mühl-, Wald- and Weinviertel , see: Günter Stummer, Lukas Plan: Speldok-Austria - Handbook for the Austrian cave directory including the Bavarian Alpine region. Association of Austrian Speleologists / Karst and Speleological Department of the Natural History Museum Vienna, Vienna 2002 ( PDF 2 MB), p. 84.
- ↑ the subgroup 1921 Vienna Basin west of the Leitha is the only one in the subgroup 1920 Vienna Basin west of the Leitha , ibidem
- ↑ cf. Geomorphological classification of the Czech Republic
- ↑ cf. Geomorphological classification of Slovakia
- ^ Bernhard Atzenhofer, Rudolf Berka, Magdalena Bottig, Anna Brüstle, Christine Hörfarter, Gerhard Schubert, Julia Weilbold: Vienna Basin. In: Summary report of geological models. TRANSENERGY - Transboundary Geothermal Energy Resources of Slovenia, Austria, Hungary and Slovakia, 2012, pp. 141–152. ( PDF 15.7 MB).
- ↑ Paragraph according to G. Gerstbach: Determination of the sediment thickness from deviations from the perpendicular in the “Vienna Basin” test field. Journal of Surveying. Volume 107, No. 8, 1982, pp. 346-357
- ^ Harzhauser, Kováč, Roetzel: Vienna Basin and its satellite basins. 2008 (see literature ), p. 1063.
- ↑ for details see Bernhard Riegel, Werner E. Piller: Biostromal coral facies - a Miocene example from the Leitha Limestone (Austria) and its actualistic interpretation. PALAIOS. Volume 15, No. 5, 2000, pp. 399-413, doi : 10.1669 / 0883-1351 (2000) 015 <0399: BCFAME> 2.0.CO; 2
- ^ Nullipora ramosissima (= Lithothamnium ramosissimus ), described in: August Emil Reuss: Die Fossilen Polyparien des Wiener Tertiary Basin. In: Scientific treatises. Volume 2, No. 1, 1847, p. 29 ( HathiTrust )
- ↑ For further details on the history of sedimentation and the stratigraphic structure of the Sarmatian in the Vienna Basin, see Mathias Harzhauser, Werner E. Piller: Integrated stratigraphy of the Sarmatian (Upper Middle Miocene) in the western Central Paratethys. Stratigraphy. Volume 1, No. 1, 2004, pp. 65–86 ( PDF 1.1 MB)
- ↑ Kurt Decker, Herwig Peresson, Ralph Hinsch: Active tectonics and Quaternary basin formation along the Vienna Basin Transform fault. In: Quaternary Science Reviews. Volume 24, No. 3-4, 2005, pp. 307-322, doi: 10.1016 / j.quascirev.2004.04.012
- ^ Mathias Harzhauser, Godfrid Wessely: The Karpatian of the Korneuburg Basin (Lower Austria). In: R. Brzobohatý, I. Cicha, M. Kováč, F. Rögl (eds.): The Karpatian - a lower Miocene stage of the Paratethys. Masaryk University, Brno 2003, pp. 107-109. ( PDF 592 kB)
Web links
Coordinates: 48 ° 12 ' N , 16 ° 22' E