Schweinfurt Basin

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Schweinfurt Basin
Schweinfurt Basin: blue villages are inside, red ones outside the basin
Schweinfurt Basin: blue villages are inside, red ones outside the basin
Systematics according to Handbook of the natural spatial structure of Germany
Main unit group 13 →
Main Franconian plates
About main unit 136 →
Schweinfurt Basin
Natural space 136 →
Schweinfurt Basin
state Bavaria
Country Germany

The Schweinfurt Basin is an approx. 150 km² large morphological hollow form of low relief in the Lower Franconian district of Schweinfurt . The system is geologically caused by the Schweinfurt Mulde . The Main flows through the basin as a central shaping medium, approximately from NE to SW. In the northwestern part of the Schweinfurt basin, the Wern cut is the characteristic element of the landscape. The elongated ridge between the two rivers divides the Schweinfurt Basin into a larger part to the southeast ( Röthlein - Schweinfurt ) and a smaller part to the northwest ( Geldersheim- Poppenhausen )
As an independent natural area , the Schweinfurt Basin is the main unit 136 within the natural area main unit group 13 - Mainfränkische Platten .

However, this definition does not correspond to the topography , as the basin landscape between Main and Volkach (green on the map) is arbitrarily cut through and higher, north-western areas (beige) are included. The latter are located between Dittelbrunn , Niederwerrn and Maibach as a base about 70 m elevated on average above the southern lowlands, into which you can look down from there. Therefore, this determination is more of a theoretical nature and is not publicly noticed. Here, the Schweinfurt Basin is the clearly visible lowland, from the Main in the north to about the lower edge of the map (Volkach).

location

The Schweinfurt Basin is located centrally and completely within the outer borders of the Lower Franconian district of Schweinfurt. The district-free city of Schweinfurt, located within the district, is largely (SW-Mitte, -Süd, -West) in the basin area, as are the places in the district within a radius of 10 to 12 km to the south and west.

Tectonics and geology

Main between Schweinfurt Basin (right) and Hesselbacher Waldland , near Mainberg

The layout of the geomorphological form is geologically - tectonically based. The Main Franconian plates generally consist of sedimentary rocks of the Muschelkalk and the Lettenkeuper lying above, while the Middle Keuper is still preserved in tectonic subsidence areas.
In the Pliocene , a tectonic bending formed a NW-SE trending trough . Simultaneously, faults trending in parallel were reactivated, especially the Kissingen - Haßfurt fault zone, which borders the basin in the north. In the central area of ​​the Schweinfurt Mulde the somewhat younger rocks of the gypsum keuper have been preserved. Due to their high clay content, these are relatively easy to erode . In the Pliocene and Pleistocene , the Main was able to change its course almost at will and clear out material. Widespread occurrences of old river gravel testify to the constant changes in course .
In the dry and cold sections of the cold periods , silty or sandy substrate was blown by westerly winds in the areas that were not worked over by flowing water . Within the Main arc, southeast of the Main Line, there are large areas with drifting sand that was blown out of the Main Terraces immediately to the west in the Pleistocene . Outside the curve of the Main, to the west and north of the Main line, there is (finer) loess , which has traveled greater distances over the Main Franconian Plates and consequently has smaller grain sizes.

Demarcation

View from the Steigerwald over the Steigerwald foreland into the Schweinfurt basin

In addition to the Main Valley system, the Schweinfurt Basin is one of the lowest lying units within the Main Franconian Plates. In the center the heights are around 200 m above sea level. NN, at the edges up to 300 m above sea level. NN reached.

In the southeast, the natural area Schweinfurt Basin (main unit 136) merges into the Steigerwald foreland (137). This is mostly also laid out in soft Keuper rocks and also has a low relief. In the northeast, the complex Kissingen-Haßfurt fault zone borders the mountainous Hesselbacher Waldland (139), which mainly consists of hard limestone rocks. The Kissingen-Haßfurter saddle running here forms the tectonic counterpart to the Schweinfurt Mulde. The Wern-Lauer-Platten (135) in the northwest of the basin have a hilly relief, as harder layers of the shell limestone are cut. In the southwest are the flat, undulating loess-covered Gäuplatten in the Main Triangle (134). In the south of the Schweinfurt basin (especially with the crossing of the Wipfeld - Prichsenstädter fault zone) the Main cuts deep into the rocks of the shell limestone, and thus enters the independent natural area of ​​the Middle Main Valley (133).

See also: Introduction

Climate and landscape

Schweinfurt Basin:
bird sanctuary near Garstadt am Main

The deep basin is a drying room within the already relatively dry Main Franconian plates. The average annual rainfall rarely exceed 600 mm, in central parts they are less than 550 mm, at moderate temperatures averaging about 9 ° C The broad, flat flood plains of the Main valley with predominantly alluvial soils , which tend to be occasionally waterlogging - they are not provided by commercial and Industrial areas are sealed - using grassland . The cut-off oxbow lakes of the Main are of ecological importance . The old river terraces above the floodplain zone have been partially dismantled for sand and gravel extraction, as have drifted sand, as is evident from several quarry ponds. The drifting sands in the Main bend lead to acidic podsolic soils or boggy soils. Agriculture is practiced on sandy brown soils , especially vegetables and herbs. On the Middle Keuper or its top layers, dense clayey brown soils to pelosols develop , which are difficult to work with and have various suboptimal properties. The flat, undulating loess areas in the west of the Main bear very fertile, but erosion-prone parabrown soils and are under intensive agricultural use. Only on the steeper slopes of the Werntal or the tributaries do Keuper sites occur on the surface, which tend to have poorer soils. In the valley floor of the Werntal there are mostly floodplain soils under grassland use. The Schweinfurt agglomeration (Schweinfurt and directly adjacent places) is distant from nature, characterized by strong anthropogenic sealing and canalization of the Main and is separated from the Schweinfurt Basin zone in cultural landscape structures. The BfN's description of the cultural landscape names 13600 Schweinfurt Basin as an area of arable farming west and south of Schweinfurt, within the boundaries of the main unit 136 Schweinfurt Basin. The agglomeration area 309 Schweinfurt with its nature-remote character encompasses the urban area, which is largely within the main unit 136 and to a lesser extent in the main unit 139 - Hesselbacher Waldland, which is adjacent to the northeast .

See also

literature

  • Johannes Müller: Basic features of the natural geography of Lower Franconia (= Franconian landscape 1) . Klett / Justus Perthes Verlag, Gotha 1996, ISBN 978-3623005003
  • Joseph Schwarzmeier: Geological map of Bavaria 1: 25,000 - sheet no. 5927 Schweinfurt with explanations . Bavarian Geological State Office, Munich 1982.
  • Wulf Hegenberger: Geological map of Bavaria 1: 25,000 - sheet No. 5926 Geldersheim with explanations . Bavarian Geological State Office, Munich 1969.
  • Hiking map of the Schweinfurt district 1: 50,000 - sheet no.87 . Fritsch Landkartenverlag, Hof 2014, ISBN 978-3861160878
  • Leisure map of the district of Schweinfurt 1: 75,000 . Cities publisher E. v. Wagner & J. Mitterhuber, Fellbach 2016, ISBN 978-3738103458

Web links

Individual evidence

  1. ↑ Landscape profile of the Schweinfurt Basin  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. 116 km² + * Landscape profile of the Schweinfurt agglomeration area  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. 40 km². Minus districts outside the SW basin@1@ 2Template: Toter Link / www.bfn.de  @1@ 2Template: Toter Link / www.bfn.de  
  2. ↑ a b Map services of the Federal Agency for Nature Conservation ( information )
  3. ↑ a b c Various authors: Geographical Land Survey: The natural space units in single sheets 1: 200,000 . Federal Institute for Regional Studies, Bad Godesberg 1952–1994. → Online maps
    • Sheet 140: Schweinfurt (Brigitte Schwenzer 1968; 43 pages)
    • Sheet 152: Würzburg (Horst Mensching, Günter Wagner 1963; 45 pages)
    • Sheet 153: Bamberg (Karl Albert Habbe 2004, in Mitteilungen der Fränkische Geographische Gesellschaft 2003/2004 , pp. 55-102; 48 pp.)
  4. ↑ Bavarian Geological State Office (ed.): Geological map of Bavaria 1: 500,000. 4. rework. Ed., Munich 1996.
  5. ↑ Details in: Josef Schwarzmeier: Geological map of Bavaria 1: 25,000 sheet No. 5927 Schweinfurt with explanations . Bavarian Geological State Office, Munich 1982. P. 68.
  6. ^ Josef Schwarzmeier: Geological map of Bavaria 1: 25,000 sheet No. 5927 Schweinfurt with explanations . Bavarian Geological State Office, Munich 1982. p. 14
  7. ↑ Johannes Müller: Basic features of the natural geography of Lower Franconia (= Franconian landscape 1). Justus Perthes Verlag, Gotha 1996. p. 56
  8. ^ Wulf Hegenberger: Geological map of Bavaria 1: 25,000 sheet No. 5926 Geldersheim with explanations . Bavarian Geological State Office, Munich 1969. p. 8.
  9. ↑ Landscape profiles of the Federal Agency for Nature Conservation ( information )