Sanding up

In geology, sanding is understood to mean the formation of a layer of loose sediment , in particular sand and silt .

In the region, sanding is also used to describe the anthropogenic pile of sand, especially in Bavaria and Austria . It is mainly used:

• as a substructure for a dry screed , as a sand bed for decorative stones or for paving a square
• for improving lumpy and clayey soils in horticulture , and on a larger scale
• for draining settlements or in tourist areas. If operated to a greater extent, it can lead to undesirable subsidence or hinder the natural development of the soil in the coastal lowlands .

The word Aufsandung is associated with a third term that relates to the transfer of ownership of real estate . Today the word is only handed down in the legal term of the declaration of revocation for the land register (in Germany abandonment ) and can either be traced back to the writing sand (confirmation of a document) or the "posting" of fiefs (restitution of fiefs to the liege lord).

On the geology of sand deposits

The above-mentioned, mostly near-surface sand layers or sand lenses - which, however, can also reach greater depths through tectonics - arise either as deposits in / from fresh water ( lakes , rivers , streams), from brackish water (especially at estuaries ) or from the sea . In most cases they allow a stratigraphic assignment of the geological processes (see also chronostratigraphy ), and sometimes an estimate of the height of the water or sea ​​level .

For example, the Nördlinger Ries (southern Germany) caused the so-called barley sands to be silted up by the erosion of its ejecta caused by an asteroid . Through detailed lithostratigraphic studies of these formations , Stuttgart geoscientists were able to determine that the sea molasses formed there a few million years later than expected and took place in the Badenian (Middle Miocene ). How quickly the then low sea ​​level rose (~ 15-14 million years ago) can be estimated from the "barley sands".

In the Wadden Sea near Bremerhaven and near Hamburg , the succession of vegetation on the dunes can be correlated with the sanding rate on the beach and the processes of soil formation . There are further connections to periods of flooding , silting and to the phenomena of waves and drifting sand .

When sanding up rivers , a vertical refinement can often be observed (above finer grain size ), which typically reaches a few decimeters in height. In the area of floodplains (see 3rd web link, geological excursion Salzach ), in the course of the " floodplain dynamics " , such sand lenses can also get under the clay of the soil layer on which they were originally deposited.

See also

• Gravel , sand bed
• Alluvium , sandbank , gravel terrace

Individual evidence

1. ↑ Building services: surface heating on gravel bed and sanding

Web links

Wiktionary: Aufsandung  - explanations of meanings, word origins, synonyms, translations

• Barley sands of the southern German molasse and relationships with the Ries impact
• Geological excursion to Southeast Bavaria, Sur and Salzach (PDF file; 358 kB)
• "Bottomless without soil", soil protection section 3.6 (PDF file; 1.09 MB)
• House technology: surface heating on gravel bed and sanding
• Fiefdoms of Emperor Rudolf II, 1579