Bay window or trochitic limestone
The bay window or Trochitenkalk is a natural stone that at Erkerode on Elm in Lower Saxony already in the outgoing Romanesque was used as Nutzgestein. It is a light yellow, porous limestone, which is composed of fossil remains. Most fossils are stalk members of animals, the sea lilies, which are also called crinoids . The individual limbs are disc or wheel-shaped and have a tube in the middle as a nerve canal. The shape of the stem links has given rise to mystical things since the Stone Age. The rock layer was formed in the Upper Muschelkalk in the trochitic limestone formation about 210 million years ago.
Naming
Trochites (Latin trochus means wheel, disc, top, ring) are the petrified, ring-shaped stalk members of the sea lilies of the species Encrinus liliiformis . They were abundant in places in the Germanic Basin , and when they died and sank to the sea floor, they formed a layer of rock. These limestones are classified as trochitic limestone . A more recent thesis assumes that sea lilies occasionally formed limestone reefs.
The sea lilies fed on plankton . They are echinoderms and have a calyx with five arms at the top, which protects the soft body of these animals. Dividing the base of the arms resulted in 10- or 20-armed chalices. The arms of the chalices were feathered and food was taken over them. The sea lilies lived in warm, turbulent shallow seas and were probably based on the sea floor. A specimen attached to driftwood was also found.
Today only a few species of sea lily exist. These live mainly in the deep sea.
Petrographic composition
Erker or trochitic limestone is composed of 67 percent biogenic components, 25 percent ooids (spherical-oval, small mineral bodies) and 8 percent oncoids (layered mineral grains with a concentric shell). In addition to sea lilies, this limestone contains fossil remains of lime from mollusks , mussels ( bivalves ), arm pods (brachiopods) and snails (gastropods). The length of the fossil remains is up to three centimeters. The ooids have biogenes as their core and have a grain size of 0.3 to 0.8 millimeters, the oncoids of the Erker or Trochitenkalk have a grain size of 0.5 to 1.0 millimeters.
The calcareous binders have a volume share of 36 percent, the biogenic components 62 percent and the visible pore space 2 percent.
Occurrence and use
The Erker or Trochitenkalk was broken on the Westhölzchen of Erkerode. It is a limestone deposit of the Upper Muschelkalks named after the place Erkerode. The occurrence occurs close to the surface at Erkerode. The rock layer is about ten meters thick and consists of up to 99 percent calcium carbonate (CaCO 3 ) in the form of calcite (lime spar). This is a very pure limestone. In the direction of Asse , Dorm , Ummendorf , Sülldorf , Staßfurt and Quedlinburg , the trochitic limestone changes into layers of marly clay and limestone. Further trochitic limestone quarries near Erkerodes are in the western Elm near Hemkenrode (cement and lime production, until 1971), on Eichberg im Elm, near Kneitlingen and Evessen .
The weathering behavior of the oriel or trochitic limestone differs depending on the rock layer: it bleaches in the sun and the biogenic components are exposed to the elements, dissolved and ultimately washed away. The stem links are not only extremely brittle and resistant in the composite rock, the binding agent of the rock has less strength. The rock is difficult to work with by hand, so you can hardly find it profiled or shaped as a work of art.
Most of the trochitic limestone deposits were supplied to sugar factories because of their purity , since milk of lime is needed for production, or used for cement production. The Erker or Trochitenkalk is said to have been burned in lime kilns for the production of lime until around 1700.
Erker or trochitic limestone was regionally used in solid construction as masonry stone, wall piers or for quarry stone masonry . When used as natural stone masonry , both oriel or trochitic limestone and Elm limestone were used. Well-known art-historical uses of Erker or Trochitenkalk are individual bricks of the church in Evessen , Erkerode and in Hachum (built in 1333) as well as in the buildings of the commander in Lucklum . All profiled door and window frames on the structures mentioned are made from Elm limestone. Numerous base walls of settlement and farm houses in the area around Erkerode are built with this stone. This rock is also used as stone paving in old farms, which were collected as reading stones in the fields.
- Masonry made of oriel or trochitic limestone and Elm limestone
Romanesque church building in Erkerode
Church in Lucklum
Church tower in Evessen
Church in Hachum
The occurrence of Erkerode is known regionally, as the mineral collector Otto Klages (1903–1982) found numerous well-preserved sea lilies there, specimens of which are exhibited in a mineral collection in Königslutter . An exhibited specimen has a handle length of 70 cm.
There is a so-called adventure quarry of the trochite occurrence not far from Erkerode, on the north-eastern edge of the forest of Evessen am Markmorgen , above the fruit growing settlements . There is an outcrop in a former quarry with a three to four meter high rock wall in an eight meter thick rock layer.
mysticism
The fossilized stems were processed into jewelry as early as the Stone Age. Such a necklace from the Neolithic Age was found in France . There is something mystical about the trochites. For the Teutons they were symbols of bravery, and in the time of Christianization they were confiscated as Boniface pennies. They were also called Wichtelpfennige or witch money .
Trochites were still used in pharmacies as a remedy for various diseases, such as epilepsy , depression , nosebleeds and other ailments until 1700 . They were crushed into powder or swallowed whole. The trochites of Erkerode were popularly referred to as sun wheel stones , sun stones and wheel stones ; and that is why it is assumed that historical half-timbered houses have used the shape of the trochites as half-suns with a notched edge and an indicated sewer pipe as protective symbols.
Further occurrences of trochite-bearing limestones
In numerous limestones that were used historically and today z. Sometimes trochites are no longer broken down. Some examples are:
- Mittenwald Hierlatzkalk, Mittenwald in Upper Bavaria,
- Füssener Hierlatzkalk, Hohenschwangau near Füssen in Bavaria,
- Tegernsee limestone, near Scharling- Kreuth in Upper Bavaria,
- Ruhpolding limestone, Ruhpolding in Upper Bavaria,
- Lippe trochitenkalk, Bentrup near Detmold in North Rhine-Westphalia,
- Bollard Trochitenkalk, Polle near Holzminden in Lower Saxony,
- Belgian granite (under construction in 2009).
- Fludergraben marble (Hierlatzkalk), Salzkammergut in Austria
literature
- Wolf-Dieter Grimm, picture atlas of important memorial stones of the Federal Republic of Germany , ed. from the Bavarian State Office for Monument Preservation, Rock No. 174, Lipp-Verlag, Munich 1990, ISBN 3-87490-535-7 .
Individual evidence
- ↑ Grimm: Bildatlas der Denkmalgesteine, Gestein No. 174 (see literature)
- ↑ W. Dienemann and O. Burre: The usable rocks Germany and their deposits with the exception of coal, ores and salts , p 382, Enke-Verlag, Stuttgart 1929th
- ↑ Sea lilies in the shell limestone. The quarry on "Markmorgen" on the Elmrand by Evessen , ed. v. State Office for Mining, Energy and Geology in Lower Saxony, accessed on August 15, 2009
- ↑ Sea lilies from the Muschelkalk: Naturhistorisches Museum Braunschweig ( Memento of the original from October 6, 2009 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed August 15, 2009
- ↑ Bonifatiuspfennige at www.wissenschaft-online.de , accessed on August 14, 2009
- ^ Information about trochites from Fritz J. Krüger , Braunschweiger Zeitung of November 1, 2001, accessed on August 14, 2009
Coordinates: 52 ° 12 '6 " N , 10 ° 42' 59.9" E