Molasse wall at Seltmans

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Molasse wall at Seltmans

The Seltmans Molasse Wall is a geotope northwest of Weitnau in the Oberallgäu district . The approximately 15 m high rock face is made up of fine to coarse-grained sediments from the Upper Seawater Molasse of the Eggenburgian to Ottnangian .

geology

Alternating bearings made from conglomerates and fine sandstones

The outcrop in the valley of the Lower Argen near Seltmans is regionally located in the southern part of the foreland molasse . In the Lower Miocene - about 20 million years ago ( Burdigalium ) - the sea penetrated from the southwest into the northern Alpine region and within three million years deposited several hundred meters of fine to coarse clastic, marine to limnic - fluvial sediments.

The area of ​​Weitnau - Seltmans was at this time on the southern edge of a marine sea basin near the Miocene coastline. The structure of the sequence of layers of the rock face clearly shows the strong influence of the coarse-plastic fillings from the area of ​​the high ridge .

The basis of the sequence of layers in Seltmans are fine to medium-grain sand and marl stones that were deposited in the marine area. They are overlaid by several alternating sequences of sand and marl stones formed near the coast, in which coarse conglomerate banks ( Nagelfluh ) are embedded, which were deposited in the delta area of the Hochgrat alluvial fan and which interlock intensively with the shallow water sediments of the sea basin.

Numerous sediment structures, the cross , ripple , flaser and inclined stratification , exposure marks on the underside of the stratum and bioturbation can be seen on the outcrop . The sandy marlstones are often incorporated into the conglomerates in a lens shape and demonstrate the changeable deposit conditions on the southern edge of the Molasse Sea.

The outcrops of the poorly sorted pebbles consist of approx. 40% fine to coarse-grained sandstones and 5–10% gneiss that was transported from central parts of the Alps into the foreland basin .

The Geotope Molasse-Wand NW of Seltmans has been classified by the Bavarian State Office for the Environment as a geoscientifically significant geotope (geotope no. 780A026) with a suitability as an excursion and research object.

  • View of the underside of the layer with exposure marks

  • Sandstone lenses in a marl layer

  • Storage of marl stones in the conglomerate fill

  • Wedging marl layer

  • View of the underside of a layer of fine sandstone

Todays situation

The Molasse outcrop at Seltmans is now used as a climbing garden . In some places, rock securing measures have been implemented to protect climbers. Climbing routes were marked and in some cases provided with safety hooks.

See also

Individual evidence

  1. ^ Herbert Scholz: Building and Becoming the Allgäu Landscape . 3. Edition. Schweizerbart, Stuttgart 2016, ISBN 978-3-510-65333-1 , p. 165 ff .
  2. ^ Ulrich Lagally, Stefan Glaser, Elisabeth Jobe, Georg Loth, Andreas Murr, Hubert Schmid, Wolfgang Schmid, Klaus Schwerd, Stephan Sieblitz and Ulrich Teipel: Geotope in Schwaben . In: Bavarian State Office for the Environment (Ed.): Earth science contributions to nature conservation . tape 7 . Augsburg 2009, ISBN 978-3-936385-34-2 , pp. 70 .
  3. ↑ Dorothea Fieling: Stratigraphy and facies of the Upper Marine Molasse (OMM) of south westernmost Bavaria (Allgäu) - dissertation Ludwig Maximilian University . Munich 2009, p. 10 .
  4. ↑ Geotope data sheet of the Bavarian State Office for the Environment: Geotope no. 780a026 Molasse wall from Seltmans , accessed August 10, 2016.
  5. ↑ Seltmans climbing garden. German Alpine Club, March 1, 2013, accessed on August 12, 2016 .

Web links

Commons : Geotop Molasse wall at Seltmans  - collection of images, videos and audio files


Coordinates: 47 ° 38 ′ 42.1 ″  N , 10 ° 5 ′ 2 ″  E