Brunswick Rogenstein

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Flat-ground Brunswick roe stone with clearly recognizable red ooids, pattern approx. 9 × 4 cm
Brunswick roe stone with exposed ooids, pattern approx. 11 × 8 cm
Red roe stone as masonry and light, profiled and delicate building pieces made of Elm limestone (especially on the triangular tympanum field) on the south-east facade of the Martinikirche
Masonry from Braunschweig Rogenstein

The Braunschweiger Rogenstein is a natural stone that was mined from the Middle Ages to the 18th century in a deposit on the Nussberg in the Prinz-Albrecht-Park landscape protection area in Braunschweig in the state of Lower Saxony . It is a historically significant stone in the Braunschweig region . The Braunschweiger Rogenstein is petrologically an oolithic limestone with relatively large, originally calcitic ooids, the layer structure of which is still very well preserved. It belongs to the lower red sandstone , which was formed about 250 million years ago.

Origin and occurrence

Northern Germany was part of the Germanic Basin when the Braunschweiger Rogenstein was formed . The components of the Braunschweiger Rogenstein, the ooids, were formed in a high-energy environment under flat water cover. The storage area can be imagined as a large inland lake with no outflow (technical term playa or salt flat ). Since clays and sands were washed into the Germanic Basin by rivers, the locations of the Braunschweiger Rogenstein deposit change with sand and clay deposits.

Geological situation of the occurrence on the Nussberg

The Rogenstein in Braunschweig am Nussberg would normally have to lie at a depth of several hundred meters, but it was transported upwards over long periods of time through an underlying salt dome and came to the surface of the Braunschweig Nussberg. There it was mined until the 18th century to a depth that was possible with the aid of technical aids from that time. The former quarry was a so-called Schurf exposed in December 2007 to a height of 1.5 meters. On the basis of this exposure , one can see that the rock layers of this Rogenstein are steeply set up and one can partially look at the sequence of rocks of the Braunschweiger Rogenstein again.

Rock description and use

It is a clearly stratified, red oolithic rock. The Rogenstein emphasizes buildings with its rich, dark red color. If the Braunschweiger Rogenstein weathers, it can very rarely fade beige. Weathering causes the ooids to emerge plastically. This limestone resembles red fish roe , because it contains round or oval spherical shapes up to five millimeters in size. The ooids are cemented by binding agents, these are calcite (49%) and quartz (37%) and there is also a small amount of mica , rock fragments, feldspar and heavy metals .

Rogenstein is well weatherproof. It seldom switches off over a large area, individual ooids partially sand off. It can hardly be profiled by hand, but it can be processed relatively easily into smooth masonry or ashlar . For this reason, profiled stone, structural ornaments and sculptures made of Elm limestone and Braunschweig roe stone were used for simple, smooth masonry on numerous buildings in Braunschweig . The hardness and durability of the Braunschweig roe stone is mainly due to its high quartz content .

In addition to solid buildings, Rogenstein could be used as stone for floor slabs, window sills and stairs, pavement slabs and rarely for graves and monuments. There are also numerous historical foundations made of roe stone in Braunschweig. It was installed on Dankwarderode Castle , Katharinenkirche (now the intermediate walls plastered), Aegidienkirche , Martinikirche as well as on the old town hall and especially on the westwork of the Brunswick Cathedral , as well as on numerous other buildings in Brunswick and in the immediate vicinity.

A regional historical specialty are cannon balls made from Braunschweig Rogenstein .

Further mining of roe stones as stone

There were other deposits of Rogenstein that were previously mined in the Braunschweig area at Thieder Lindenberg , Harly near Goslar , Heeseberg near Jerxheim and in the Asse near Wolfenbüttel .

literature

  • Wolf-Dieter Grimm: picture atlas of important monument rocks of the Federal Republic of Germany. Published by the Bavarian State Office for Monument Preservation, Lipp-Verlag, Munich 1990, ISBN 3-87490-535-7 .
  • Henning Zellmer, Ewald Ockenga: The Rogenstein from the Braunschweiger Nussberg . Edited by State Office for Mining, Energy and Geology, Hanover o. A. Available online: Zellmer / Ockenga: Der Rogenstein vom Braunschweiger Nußberg (PDF; 321 kB)

Web links

Commons : Braunschweiger Rogenstein  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Josef Paul: Oolites and stromatolites in the Lower Buntsandstein. In: Norbert Hauschke and Volker Wilde (Hrsg.): Trias A whole different world of Central Europe in the early Middle Ages. P. 263–270, Verlag Dr. Friedrich Pfeil, Munich 1999 ISBN 3-931516-55-5
  2. ↑ Grimm: Denkmalgesteine, Gestein No. 164 (see literature)
  3. ↑ Otto Sickenberg: stones and earth. The deposits and their management. Geology and Deposits in Lower Saxony, 5th volume Dorn-Verlag, Bremen, Horn 1951, pp. 280 and 282

Coordinates: 52 ° 16 ′ 22.6 ″  N , 10 ° 33 ′ 17.9 ″  E