Elm limestone

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Soil profile in the Elm (Hainholz visitor quarry), yellow = stone benches with Elm limestone
Hainholz visitor quarry on Steinkuhlenberg south of Königslutter

The Elm limestone , which is also misleadingly referred to as foam limestone , is a regional special development of the Terebratel banks of the Lower Muschelkalk . This limestone is locally limited to the Elm and was created from the deposits of a shallow sea in motion.

Rock description and occurrence

The Elm limestone is a porous, light yellow limestone with cross and oblique layers. It is fine to coarse-grained in layers. The fossil debris is well sorted within the layers. Larger cavities are in layers with numerous debris accumulations. The fossil debris consists of molluscs (molluscs), fragments of echinordermen and foraminifera (protozoa). Elm limestone contains 49 percent components, 35 percent binders and the visible pore space is 16 percent. The percentage of peloids is 98 percent and the remaining 2 percent are biogenic.

Its yellowish color is determined by limonite components. It is a light-colored limestone with numerous fine pores, which is usually easy to work with. So-called galls occur when stored, recognizable by dark gray deposits that resist manual processing. Stone sculptors prefer a fine-pored location in the quarry, which is also called soapstone . The stone benches are located in the so-called Oberbruch with a thickness of about 1.00 to 1.20 meters. In between are layers of marl and weathered morbid limestone. At a depth of 4 to 5 meters there is the 3.50 meter thick gap , which has an approximately 0.50 meter thick layer of limestone, the soapstone.

Quarries

The Elm limestone has been mined in the Elm ridge near Braunschweig since the Middle Ages . Since it is also very weather-resistant, it is suitable as a building material for stone buildings. The first medieval quarries in the Elm to extract the Elm limestone were built on the "Steinkuhlenberg" near Königslutter . They were originally owned by the local Benedictine monastery . Later there was a dispute with the lien holders of the Königslutter Castle. This dispute between Abbot Bartholdus Keghel and the von Weferlingen brothers was settled in 1399 by Duke Friedrich von Braunschweig . Today there are still numerous small fractures near Königslutter, which are reminiscent of the cave construction common in the Middle Ages .

The city of Braunschweig acquired Ampleben am Elm Castle in 1433 and built its own quarry, the "Ampleber Kuhle", not far from Groß Rhode .

Numerous new quarries were built in the Elm in the 17th and 18th centuries. 1650 and 1660 were called "Steinkuhlen" near Groß Rhode and on Evesser Berg. In 1672 the citizens of Schöppenstedt received the privilege of Duke Rudolf August to build a quarry for their own use in their wood (Weddy).

Other quarries were found in documents from the 18th century near Langeleben (Altfeld), Lelm (Langeleber Trift), Schöningen (above the monastery on the Elmrand), Twieflingen ( Elmsburg ), Groß Rhode, the Tetzelstein , Ampleben (Ampleber Kuhle), Erkerode , Lucklum (four in Dettumer Grund, one on the Kuxberg), Hemkenrode and Destedt mentioned. At Erkerode a special type of limestone was quarried, the Erker or Trochitenkalk .

In 1910 there were only nine quarries in the Elm, five of which were near Königslutter and four near Schöningen. In the 1930s, the break between the Portland cement factory in Drachenberg and the factory in Königslutter was connected to a cable car to transport the Elm limestone. At that time the company had 60 employees. In 1948, the Drachenberg branch of Braunschweiger Kalkwerk GmbH regained the strength of the pre-war workforce. The stones suitable for working stone were sorted out and the less usable stones were burned to make building and fertilizing lime. Blocks that were suitable for stone processing could be mined with a height of up to 1 meter and a volume of up to 8 m³. In 2008 only one quarry from the Metzner company was in operation, exclusively for the extraction of ashlar.

Hemkenrode quarry

The fossil finds from the Hemkenrode quarry are a special form of the fauna of the Lower Muschelkalk in the Elm . There is almost no fossilization of the middle shell limestone. Petrifications of sea ​​lilies can be found in the soft limestone on the edge of the Elm, especially in Erkerode . Sea lilies were marine animals with tentacles, the meter-long stems of which were attached to the seabed or to objects (mostly wood) floating in the water. Above all, the species Encrinus liliiformis was found with its compact, robust crown. In recent times, entire communities of mussel and sea lilies have been found in the Elm, which represented narrow, reef-like structures. The gnarled Ammon's horn ( Ceratites nodosus ), a mollusc related to today's squid, is also found frequently .

geology

Elm limestone at a former quarry

According to the deep boreholes, the Elm must have emerged from the bottom of an earlier sea in the Triassic (about 200 million years ago). The marine animals living in it, the terebrateln , formed a layer of limestone, from which limestone was later formed through compaction. After that, the sea floor arched to form a ridge due to saddle formation, which took a period of 100 million years between the Jurassic and the Tertiary . Today the Elm consists of shell limestone and a 500 m thick layer of red sandstone. Below is a 900 m thick salt warehouse from the Zechstein Age . The rocks that form the Elm belong to the Muschelkalkzeit. This includes limestone up to 200 m thick lying below in different layer sequences, e.g. B. Tuber lime, corrugated lime, marl, foam lime. The up to 1.5 m thick layers of foam lime, so-called stone benches, can be used as stones for building projects. Limestone up to 8 m² in size could be extracted. This stone material, which is suitable for processing, only comes to the surface in the northern part of the Elm, where it is mined. Below this terebratel layer is the 0.5 m thick layer, which is particularly dense and suitable for filigree stone carving work. The local stonemasons call this layer soapstone .

Originally the Elm was about 200 m higher than it is today, but was removed again by the action of water, ice and wind. This was especially the case during the Ice Ages , which gave the ridge its rounded shape by grinding. During the ice ages, the Elm was covered by glacier ice, which can be recognized by the scattered boulders . During this time it received a layer of loess up to 60 cm thick, which in connection with the limestone below was beneficial for the later tree population.

Fossils

Petrifications can be found in almost all layers of the Muschelkalkzeit. The sea that occurred here 200 million years ago had a very high salinity. As a result, the number of species was low, but the number of individuals of the individual species was very high. The shellfish in particular are well preserved. Lime plates with specimens of the genera Omphaloptycha , Loxonema , Myophoria and Hoernesia bear witness to this .

Worms and arthropods were also buried in the mud of the ancient sea. Numerous fossil burial tunnels and feeding structures can still be found in the rock today . This also includes long tubes called rhizocorallium. The name is a designation of the trace fossils, but says nothing about the unknown producer.

In addition to the molluscs and some well-preserved goblets of the very rare sea ​​lily Encrinus carnalli , teeth and vertebrae of Nothosaurus sp. , a rowing lizard about 1 m long, and teeth of Placodus sp. , a plaster tooth dinosaur, can be found.

Elm rock as a building material

From Elmkalkstein: Kaiserdom Königslutter

Already at the beginning of the 12th century the quarries in Elm were of great importance as building materials. The surrounding land was supplied with Elm limestone. Many sacred buildings, such as churches and monasteries, but also castles and palaces around the Elm, were made from this building material. Braunschweig was therefore also called the “city of the white Elm limestone”.

Other rocks from the Elm were also used as building materials in the Middle Ages. This was the loose, porous limestone called Duckstein in Elm . Duckstein is a tufa that was precipitated from the heavily calcareous stream water of the Lutter in recent geological times and was deposited as tufa . (In geology, the terms tufa limestone , travertine and limestone sinter are used further differentiating or synonymous for spring limestone, inconsistent .)

The material was easy to break and worked well when it was not yet dried out. Duckstein served as an ornamental stone for the grottoes in the baroque garden of Salzdahlum Castle . The top-fermented beer brand Duckstein is named after the rock material Duckstein , which was originally brewed in Königslutter am Elm, where the Lutter rises.

Elm lime was not only used for construction purposes. The limestone was also burned in lime kilns to make quicklime . Historical lime kilns were located at the Lutter spring near Königslutter, near Schöningen , on the Elmsburg, in Weddy, near Groß Rhode, on the Ampleber Kuhle, near Erkerode , in Dettumer Grund, on the Kuxberg and near Destedt. Also gypsum was in Reitlingstal won the Elms and Schöningen near the former salt mine. An old gypsum quarry can still be seen to the west of today's restaurant in Reitlingstal.

Construction use of the Elm rock

12th to 14th centuries

From Elm limestone: Tomb in Braunschweig Cathedral around 1227

The Ludgeri Chapel in Helmstedt, built in the 11th century, is considered to be the oldest preserved building in which Elm limestone was used . Another important building made of Elm limestone in the region is the 1135 by Emperor Lothar III. Königslutter collegiate church built by Süpplingenburg, the imperial cathedral .

In Braunschweig, Elm limestone was preferred for finer architectural parts of building projects such as columns , capitals and cornices . Here are great examples of Elm limestone uses:

The top floors of the three main parish churches of Braunschweig ( St. Martini , St. Andreas and St. Katharinen ) consist mainly of limestone.

15th and 16th centuries

From Elmkalkstein: Gewandhaus Braunschweig around 1590

The importance of the Elm limestone for building projects in Braunschweig results from old craftsmen's calculations. For the new construction of the town hall ("to the rathuse, to the dornssen, to the winkelere"), 1162 shock (around 70,000 stones) and 32  loads of stones were used in six years around the year 1460  . The stones were called "Luttersche stones" because of their predominant origin from Königslutter .

The statues of the “Rolande”, which are embodiments of old rights and freedoms in medieval cities, were also made from Elm limestone. The oldest and most important among them is the 5.45 meter high Roland Roland . It was erected in front of Bremen's town hall in 1404 to replace the wooden statue that burned down in 1366. The base of the Halberstadt Roland also consists of Elmstein .

For the main church in Wolfenbüttel , built in the Renaissance style from 1604 to 1623 , the Duke of Braunschweig had stones brought from the Elm quarries "Lutterkuhle" and "Teufelsküche". In 1591 the magnificent facade of the Braunschweiger Gewandhaus was made from Elm limestone .

The quarrying of the Elm limestone was strongly promoted by Duke Julius of Braunschweig . He was considered an intellectually open-minded prince with an interest in mining, metallurgy and quarries. In 1575 he published an "instrument book" with reference to the quarries of Elm, Asse and Ösel , which described the tools. In it the duke developed plans for the removal of the stones, which should be carried out via rivers. To do this, he wanted to make the Altenau (known as Nette) navigable and to build a barrage so that the stones from the Elm (Kneitlinger Kuhle) and the Ösels could be transported to Wolfenbüttel. The transport from the quarry in the mountain down to the river should take place on wooden slide rails (sliding art). In 1577 the Altenau was regulated so that it could be navigated with rafts.

20th century

Buildings

Larger buildings from the first half of the 20th century, in which Elm limestone was used:

after 1945:

Monuments

Eulenspiegel monument

Well-known monuments from Elm limestone are:

Processing industry

At the beginning of the 20th century, larger industrial companies that processed limestone emerged on the Elmrand:

  • Braunschweigisches Elmkalk- and Steinwerk near Hemkenrode in 1904, founded by the Royal Prussian Railway Inspector Mühlen: Production of quicklime for building and fertilization
  • Reconstruction of the stone works near Hemkenrode in 1946 by lime specialist J. Schnuch: Development of a new quarry in Destedter Forest and cable car connection to the plant
  • Establishment of a cement factory near Hemkenrode 1954: Production of building lime with the brand "Elmkreuz" and Portland cement with the brand "Elmkreis"
  • Lime works on Scheppauer Weg in Königslutter, which was connected to the quarries by cable car

Geoscientific exhibitions

There are two geoscientific exhibitions in Königslutter :

  • The Otto Klages Collection , a collection that the merchant Otto Klages brought together in the 20th century. The core of the 20,000 individual items are fossils from the Elm. The collection includes several hundred specimens of petrified sea lilies, including a large stone slab with 16 sea lily crowns and stems up to 70 cm in length. Rocks and minerals are also shown. (Königslutter, Sack 1)
  • The Königslutter Geopark Information Center with numerous exhibits on geology , petrology and mineralogy of the Harz National Geopark. Braunschweiger Land. Ostfalen , which also includes the Elm. (Königslutter, An der Stadtkirche 1)

Popular beliefs and customs

The trochites, which were widespread in the Elm rock, were used as early as the Stone Age . These are the stalk members of the sea ​​lilies , which were formed from the carbonate of the crinoid skeletons. Stone Age people made necklaces from the disc-shaped trochites, similar to a coin. They could be threaded through the hole in the middle of the tochites, which the animals used as a nerve channel. For the Teutons , wearing trochitic limestone chains was a sign of bravery. This importance was retained for a long time: during Christianization, pagans had to give up their trochites as Boniface pennies, Wichtelpfennige or witch money. Trochites were still found in pharmacies in 1714 as a remedy for epilepsy, poisonous animals, nosebleeds, dizziness and kidney problems. They should also promote bravery, facilitate the afterbirth, and bring the owner a long life.

literature

  • Heinz Röhr: Der Elm , Braunschweig / Schöppenstedt 1962.
  • Jochen Lepper: Naturstein 3/98, p. 77.

Web links

Individual evidence

  1. ^ Wolf-Dieter Grimm, picture atlas of important memorial stones of the Federal Republic of Germany, ed. from the Bavarian State Office for the Preservation of Monuments, Rock No. 167, Lipp-Verlag. Munich 1990. ISBN 3-87490-535-7
  2. ↑ Otto Sickenberg: stones and earth. The deposits and their management. Geology and Deposits of Lower Saxony, 5th vol. Dorn-Verlag, Bremen, Horn 1951, p. 248ff
  3. ↑ Jochen Lepper: Building and monument stones between Elm and Aller - occurrence and use. Excursion guide Natural History Society Hanover. October 8, 2005. Self-published