Brine source

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Unitasquelle on the Kütfelsen in Salzkotten , an artesian brine spring with a concentration of up to 35 g / l sodium chloride .

A brine source , as Solquelle or salt source referred to is a natural source , the water of a natural salt content of at least 10 g / l. Brine springs are now mostly designated as geotopes and were used regionally as early as the late Iron Age for balneological purposes and locally as early as the Neolithic ( Halle a. D. Saale ) for salt extraction . Occasionally, in the balneological literature, brines developed through deep drilling are also referred to as brine springs. Such sources are more likely to be referred to as brine wells . Natural brine springs are often found in the roof area of salt domes , in the outcrop of saline rock sequences and tectonic faults that are associated with such saline sequences .

Emergence

Salt spring in Boonslick State Park in Missouri , USA
Medicinal water distribution at the Elisenbrunnen in Aachen

Natural brine is groundwater with a high proportion of sodium and chloride ions. The enrichment with these ions often takes place as part of saline effects when the groundwater comes into contact with the rock salt it contains . Rock salt bearing rocks or pure rock salt deposits are usually several hundred meters below the earth's surface. Because rock salt is very easily soluble in water, it can be easily extracted from the groundwater (geologically also called formation water ). Depending on the proportion of rock salt and other easily water-soluble evaporite minerals in the rock through which the groundwater flows, the original layer thickness can be considerably reduced, so that sub-erosion phenomena can sometimes appear on the earth's surface and secondary water pathways can develop in the rock, which further intensify subrosion. Along with major disturbances in the subsurface, sodium chloride water can penetrate rocks far away from the salt ( brine migration ) or rise to the surface and emerge there as a brine source - often artesian . Many brine springs, such as in the Münsterland , on the other hand, are fed by strongly mineralized connate waters . In the immediate swelling area, the less soluble minerals contained in the brine (mostly the carbonates ) can be precipitated and form characteristic swelling deposits .

The majority of the brine springs in Central Europe are fed by saline waters from the Upper Carboniferous ( Ruhr area ), the Zechstein (North German lowlands, Hessian basin , Thuringian basin ), the Germanic Triassic (Thuringia, Hessian basin), or the Alpine Triassic ( Berchtesgadener Alps , Salzkammergut ).

use

Depending on the composition, the salty waters can be suitable for therapeutic baths or drinking cures . In the past, brine spring waters were often evaporated in so-called boiling houses or pans ( salt pans ) to produce table salt . Today, source brines are also increasingly used in the manufacture of cosmetic products.

Examples of important brine springs in Central Europe

Spring intake of the Elisabethquelle in Bad Frankenhausen am Kyffhäuser
Exposed brine spring in the roof area of ​​the Conow salt dome (southwest Mecklenburg)

Many of the groundwater outflows referred to in the literature as "brine springs" are actually not brine springs in the sense of the definition, since their sodium chloride content is increased but is less than 10 g / l. These include, for example, the thermal springs of Wiesbaden , Aachen or the Fontaines Salées de Saint-Père . In German place names, the addition of "Bad" to the name together with the components of the name "Salz" or "Hall" often indicates the presence of brine springs in the respective locality.

The ancient Celts already used the natural brine springs in the Northern Limestone Alps in today's Hallein , Bad Reichenhall and Hallstatt . In doing so, they established the special economic and cultural importance of these settlements. There natural brines are formed by leaching the salt in the Hasel Mountains , a tectonic mélange of Permian and Triassic rock salt, gypsum / anhydrite , clay and dolomite , which is characteristic of the local geology. The salt concentrations between neighboring springs vary greatly. For a long time now, salt in the region has not only been extracted from naturally emerging brine, but rather the salt deposits are drilled into and drawn off ( leached out ) through the artificial introduction of hot water . The brine obtained in this way is then transported via pipes to the processing plants. In principle, this method is also used when extracting salt from numerous salt domes under the North German Plain (see also →  Solende salt extraction and →  Cavern storage ).

One of the best-known examples of historical salt extraction from brine springs are the salt pans in Halle (Saale) (see also →  Halloren ). Salt production is said to be there even until the Neolithic Age, around 2500 BC. Go back BC. The rise of the brine is related to the so-called Hallescher Marktplatz Fault. The enrichment of the groundwater with salt takes place in the Zechstein- Salinar ( Oberperm ).

In the spring ground in Bad Frankenhausen there are artesian sulphate- containing brine springs in a large earthfall . The source line is tied to the Kyffhäuser south edge fault, which opens up sulphatic rocks (gypsum / anhydrite) of the Zechstein there . The Elisabethquelle is enclosed in the so-called main anhydrite (anhydrite of the Leine formation , "Zechstein 3"). The brine, the sodium chloride of which comes from the Staßfurt rock salt (rock salt of the Staßfurt Formation , "Zechstein 2") stored below the Leine Formation , has been in Bad Frankenhausen since the earlier Iron Age (8th to 6th centuries BC). utilized. The so-called Schüttschachtquelle , 35 m from the Elisabethquelle, was first used for salt production and only later for balneological and drinking cures.

The brine springs of Bad Salzungen were first mentioned in 775 in a deed of donation from Charlemagne . The salt content of these springs can be traced back to the rock salt of the Werra formation ("Zechstein 1"), which only carries larger amounts of rock salt in the east of Thuringia and in the north-west of Hesse. The Burgsee, which characterizes the townscape, is due to the subrosion of the Werra Salinar.

One of the historically most important brine spring lines was on the southern edge of the Münsterland chalk basin , on Hellweg . These sources are fed by brine from the underground of the Münsterland chalk basin. These artesian brine springs supplied the brine for the salt pans in Unna-Königsborn , Werl , Soest , Sassendorf , Westernkotten and Salzkotten . The brine springs established the economic importance and prosperity of the places on Hellweg. Today the brine springs in the west in particular have dried up due to the groundwater swamp in connection with the northern expansion of the coal mining industry .

In Bad Gandersheim were in Gande several salt springs since the early tal Middle Ages used. Except for the Roswitha spring, none of the old brine springs - Ostera spring , Oda rock spring and Ludolf spring - are accessible today . The salt springs of Bad Gandersheim are also genetically linked to the leaching of the Zechstein saline underground.

In Salzgitter-Bad , the naturally flowing brine springs have been used for salt production in the saltworks hall since the beginning of the 13th century . In the local area of ​​Salzgitter-Bad, the brine reaches the surface of the earth in the area of ​​tectonic faults. There, too, the brine goes back to the leaching of the Zechstein Salinar, which is expressed on the surface of the earth by subrosion sinks that are still active today.

Individual evidence

  1. ↑ Ad-hoc-AG Geotope Protection: Working Instructions Geotope Protection in Germany - Guideline of the Geological Services of the States of the Federal Republic of Germany. Applied landscape ecology. Vol. 9, 1996, Glossary
  2. ↑ a b Keyword Hallesche Stör in: Dietrich Franke: Regionalgeologie Ost. Geological online reference work for East Germany with around 2500-page encyclopedia (PDF; 19 MB) and separately downloadable maps and tables
  3. ↑ Werner Käß, Hanna Käß (Ed.): Deutsches Bäderbuch , Stuttgart 2008, ISBN 978-3-510-65241-9
  4. ↑ Gert Michel: Balneogeology . In: Werner Käß, Hanna Käß: Deutsches Bäderbuch , Stuttgart 2008, ISBN 978-3-510-65241-9 , p. 20
  5. ↑ Werner Käß: Bad Reichenhall . In: Werner Käß, Hanna Käß (eds.): Deutsches Bäderbuch , Stuttgart 2008, ISBN 978-3-510-65241-9 , p. 776 ff.
  6. ^ G. Hecht: Bad Frankenhausen . In: Werner Käß, Hanna Käß (Eds.): Deutsches Bäderbuch , Stuttgart 2008, ISBN 978-3-510-65241-9 , p. 447 ff.
  7. ↑ G. Hecht: Bad Salzungen . In: Werner Käß, Hanna Käß (Eds.): Deutsches Bäderbuch , Stuttgart 2008, ISBN 978-3-510-65241-9 , p. 867 ff.
  8. ↑ Most important geotopes: Salzkotten headwaters. Geological Service NRW ( Memento from December 28, 2014 in the web archive archive.today ).
  9. ^ Werner Käß: Bad Gandersheim . In: Werner Käß, Hanna Käß (eds.): Deutsches Bäderbuch , Stuttgart 2008, ISBN 978-3-510-65241-9 , p. 469 ff.
  10. ^ Werner Käß: Salzgitter-Bad . In: Werner Käß, Hanna Käß (eds.): Deutsches Bäderbuch , Stuttgart 2008, ISBN 978-3-510-65241-9 , p. 831 ff.

Remarks

  1. ↑ In the balneological literature the following are regarded as brines: " Waters which contain at least 5.5 g sodium and 8.5 g chloride ions (corresponding to 240 mmol / l sodium or chloride ions) in 1 liter [... ] to lead. Recently, efforts have been made to designate only those waters as brine that contain more than 8.5 g / l chloride, regardless of the associated cation content. “From: Gert Michel: Scientific definitions of natural, localized remedies. In: Werner Käß, Hanna Käß (ed.): German bath book. Stuttgart 2008, ISBN 978-3-510-65241-9 , p. 44.