Heilbronn sandstone

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Heilbronn sandstone quarries around 1835
Samson at the Ottheinrichsbau of Heidelberg Castle made of Heilbronn sandstone. The facade consists of red Neckar valley sandstone .

The Heilbronn sandstone is a reed sandstone and is quarried near Heilbronn in Baden-Württemberg . This sandstone, which originated in the Middle Keuper , is of great cultural and historical importance for the region around Heilbronn.

geology

Exploration of an earlier Heilbronn quarry near the Jägerhaus

Heilbronn lies in the northern part of the south-west German layer level country . The Heilbronn Mountains in the east of the city reveal a section of the sequence of layers with the Heilbronn sandstone. On the 28 to 29 m thick layer of the Lower Keuper follows the 130 to 150 m thick gypsum keuper , on which the 20 to 45 m thick layer of Heilbronn sandstone, a reed sandstone, rests. This sandstone layer used to be mined intensively, the stones extracted from it shape the historic cityscape of Heilbronn. In the lower-lying town, the reed sandstone has been completely eroded and the layers underneath up to the Unterseuper have been almost completely eroded.

The Heilbronn sandstone is still being mined to a lesser extent than in the past (2010); a quarry that is still in operation is located west of the Schweinsberg (Heilbronner Berge) in the Winterhaldenhau forest area ( ⊙ ).

Rock description and mineral inventory

Heilbronn sandstone (pattern; approx. 10 × 8 cm; sawn surface)

It is a light brown fine-grain sandstone with a clay-ferritic (clay-iron) bond. It shows an evenly distributed, brown stain on its surface. These spots were created by limonite (yellow-brown iron) enrichments.

Its components are 30 percent quartz , 57% rock fragments, 12% alkali feldspar and 1% plagioclase . The accessories with a proportion of less than 1% are muscovite , tourmaline , apatite , zircon and opaque (opaque) mineral grains. The grain size is 0.14 millimeters. It is a weakly feldspar-bearing sandstone with rock fragments.

use

Due to its clayey-ferritic bond, Heilbronn sandstone is not very resistant to weathering ; he sands, leaves and switches off. Because the light mica it contains is regulated horizontally, the stone splits very easily in this direction; when installed perpendicular to the bearing, even large-scale formwork is to be expected.

This sandstone is used for monumental buildings in structural engineering and bridge construction, for stone , floor slabs, stairs, memorials and tombs. It is very popular with stone sculptors because of its easy workability .

The Heilbronn sandstone was used, for example, in Heilbronn itself at the town hall , at the Kilian's Church and at the main train station , in Bad Wimpfen at the Red Tower (as a Bossenstein ) and at the Ulm Justice Building. Sculptures on Heidelberg Castle and ornaments on Cologne Cathedral are also made from it.

literature

  • Wolf-Dieter Grimm: picture atlas of important monument rocks of the Federal Republic of Germany. Edited by the Bavarian State Office for Monument Preservation. Lipp-Verlag, Munich 1990, ISBN 3-87490-535-7

Individual evidence

  1. ↑ Otto Linck , Helmut Wild: Geological structure and geological development . In: City and District of Heilbronn . Theiss, Stuttgart and Aalen 1974, ISBN 3-8062-0121-8 . Pp. 91-117
  2. ↑ a b Grimm: Monument atlas of important monument stones. Rock No. 100 (see literature)

Web links