Lusatian granite
Lusatian granite ( Lusatian granodiorite in geological parlance ) is the group name for a useful rock that was extracted in many quarries in Upper and especially West Lusatia . In most cases, in the geological sense, it is a granodiorite of gray color with a structure reminiscent of speckles.
Deposit and petrography
The Lusatian granodiorite is the most important useful rock in the Lusatian granitoid complex (Lusatian anticline zone) and formed during magmatic processes. This massif was formed in the Precambrian during the Cadomian Orogeny and is therefore one of the oldest rock deposits in Saxony. In geological terminology, West Lusatian granodiorite is spoken of in terms of its occurrence .
The main type of material obtained as stone is a medium-grain, light gray stone when fresh. The mica type biotite emerges clearly in the form of black insets. Another typical structural feature in numerous quarries is dark deposits, called xenolites , which often have a streaky internal structure. Their size varies from a few square decimeters to dimensions over half a square meter.
The main mineral components include quartz , feldspars ( orthoclase , plagioclase , microclinperthite) and the mica biotite. There is also pyrite , which is partly responsible for the later yellowing of the rock when it has been exposed to the elements. Magnetite and apatite are also represented in small proportions . Dark mafic minerals are partially contained by embedded xenolites .
Most of the mined varieties are granodiorite containing biotite. This mica also contributes to the yellowing of the rock due to progressive alteration (decomposition due to weather influences). In a few cases, preferably in some West Lusatian deposits, another type of mica, muscovite , is contained and the rock is then referred to as two- mica granodiorite ( anatexite ).
The Saxon varieties obtained are mainly medium-grained. Coarse-grained varieties occur east of Kamenz and Schwarzkollm .
The granite around Šluknov is somewhat coarser in grain and darker in color. Some of these deposits are counted among the Rumburker granite , which is between Syeno- and Monzogranite according to its modal mineral composition.
Extraction and processing
Lusatian granite was extracted from rough blocks by wedging . In this work, the natural reservoir situation was helpful. In the best case, the horizontal separation fissures allowed a relatively uniform height of the blocks and a good separation from the bedrock. Vertical fissures are present at greater intervals and enable relatively long raw pieces to be extracted.
In Lusatia, the cable crane was mainly used to move the blocks in the quarry . Several ropes spanned the quarry and were stretched and fastened at both ends by means of pylons. On these ropes were trolleys that had a cable pull that could be used to lift the blocks. The derrick crane was only used marginally in the Lusatian quarries.
The workpieces obtained in this way were either split with wedges in the quarry or split in the workshops, which were usually nearby. Here, the good natural cleavage at many mining sites was very beneficial for the manufacture of simple products. These were particularly simple bricks or curbs.
In the sawmills there were facilities for the production of solid parts and raw panels. In this frame saws and later diamond saws used. With regard to the surface designs to be achieved, Lausitz granite is used rough sawn, ground in various stages and polished. To create targeted roughness, it can be flogged , sandblasted , embossed , pointed or flamed . Columns, balls, basins and similar parts are rotated.
Extraction
The occurrence of the mined types of Lusatian granite are mainly located on the Saxon area and to a lesser extent on the Czech side between Rumburk and Šluknov.
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In addition to the general group designation Lausitzer Granit, more specific designations of origin, such as Demitzer Granite or Kamenz Granite and other names, were and are common among users . Which stone finally came on the market under the main group name Lausitzer Granit is dependent on the long stonework tradition of contemporary influences and perspectives, as more precise geographical designations of origin were also common. Nevertheless, the general term has become commonplace in the technical language of users, architectural and regional historians and in the related literature. The difficulties of a precise distinction according to optical and petrographic-mineralogical characteristics between many mining sites justify this generic term.
The most important mining sites are in the following regions.
Saxony
Region around Bautzen
Region around Bischofswerda
Region around Demitz-Thumitz and Tröbigau (around the Klosterberg )
Region around Kamenz
Region around Königsbrück
Region around Löbau
Region around Neusalza-Spremberg
North Bohemia
near Mikulášovice / Nixdorf
near Šluknov / Schluckenau
near Velký Šenov / Groß Schönau
History of mining
The earliest use of granodiorite in Lusatia is documented by finds of small millstones from the late Bronze Age (finds from Niederkaina ). For the period between the 3rd and 6th centuries, a millstone was found near Radeberg , the origin of which was assigned to the Rödertal .
During the early granite mining, the focus was on the exposed boulders and platy secretions from the areas near the surface. This extraction method lasted until the 19th century. The stone crushers split the workpieces using stone splitting tools with linear iron wedges using a setting hammer and sledgehammer in heavy manual work. The angularity and smoothing of the still uneven surfaces on the rough blocks was the task of other specialized quarry workers.
From the 13th century, granodiorite was used in Lusatia for gravestones, baptismal fonts , stone crosses and architectural parts and has been partially preserved as such. The early quarries are believed to be near the oldest cities and can no longer be found today. The stone has been used by stonemasons in important buildings in the region since the 14th century . The examples in the Kamenz city church St. Marien and at the Bautzner Dom St. Petri testify to the high skill of the stonemasons in handling this comparatively solid material.
Stone quarrying can be seen in the Demitz-Thumitz area around 1730. Building blocks for houses and churches in West Lusatia were obtained here. In the 18th century, further mining sites are known at Bautzen, Kamenz and vom Keulenberg .
In the period from 1845–1846, rock mining in the region around Bischofswerda intensified because the new Dresden-Bautzen railway made it easier to organize the removal of the extracted material.
From the 19th century and into the second half of the 20th century, rock mining in the entire region had its economic peak. The company founded by CG Kunath and later continued by other owners was pace-setting. In 1901 this company was the first in Germany to use a mechanical stone splitting machine with a friction splitting hammer, which the director Ferdinand Weiller of the Danish joint stock company Bornholm had invented and patented. During this period, Lusatian granite was delivered to a large extent as stone to many Saxon cities in the regions of Dresden, Chemnitz and Leipzig and to other regions by shipping on the Elbe. As Lusatian granite, the stone from the countless quarries had developed into a recognized material. Nevertheless, it retained its regional architecture-defining effect. In the Ore Mountains, on the other hand, locally extracted granites and other rocks have influenced the cityscape, for example from the Eibenstocker, Kirchberger and Bergener granite massifs. Some of them are very similar to the Lusatian granite. Despite the relative proximity and high productivity of the Lusatian granite industry, he could not suppress their dominance.
In the village of Häslich near Kamenz, an association has been operating a display facility and museum of the granite industry since 1998 . This explains the mining and processing of Lusatian granite as a model.
The production of stone products in the quarries of Basalt AG in Demitz-Thumitz was stopped on January 31, 2003. These and other deposits are not exhausted. Smaller companies continue to mine their rock in various places.
Usage forms
Lusatian granite is a stone that has a very broad application history and is closely linked to the settlement culture in Upper Lusatia. The focus is on architectural purposes and road construction.
Floor coverings
Pavement , curbs , gutters and pavement slabs in Dresden and in many East Saxon cities have been made from this stone. For this purpose, the rock was delivered far beyond the borders of Saxony. As early as the first half of the 19th century, Berlin obtained a large number of its pavement slabs from quarries near Bischofswerda. A natural characteristic of the upper areas of some deposits favored this purpose. Here the rock is segregated in thin plates that are about 5 to 10 centimeters thick. Elsewhere, the granodiorite occurs in wool sack forms and did not result in such slabs. Later, the crust slabs (one side rough and bulbous, one smooth cut surface) that accrued when cutting the raw blocks brought from the quarry were formatted and delivered in the same way for road construction.
Architectural parts and stairs
In Upper Lusatia, many older door and window frames are made of Lusatian granite. Gradually this application spread beyond the region. The rapid development of the Saxon railway system boosted the sales opportunities of the stone companies by leaps and bounds.
The stone has been used very frequently for stairways in buildings and outdoors. Its favorable flexural strength values made it possible to have long steps for stairs. A bush hammered surface is typical on the accessible areas. Representative application examples can be found in and on many public buildings in Dresden.
Fountain
The favorable rock-physical values have given the Lusatian granite a preferred suitability for wells. It withstands the effects of water ice, salts and, in the contact zone, water-air relatively well.
Monuments
The Lausitz granite had initially difficult in the acceptance of Monument purposes. In Saxon cities, public administrations were very much oriented towards Swedish granite until after 1900 . This habitual definition had to be gradually loosened with a lot of persuasion by the company owners.
Gravestones made of this stone can be found in cemeteries in the Upper Lusatian region and in Dresden , although the dark types of lamprophyr were much preferred for this purpose. Quite often, grave stones were made from them and the actual tomb was designed with other available types. One reason for this is the relative frequency of the spotty xenolites in the rock.
Masonry
Many Saxon railway and road bridges, retaining walls, railway buildings and other administrative buildings (mostly the base areas) and numerous bank fortifications are built with Lusatian granite. The formats chosen were different. Often one encounters layered and Cyclops masonry. What is striking is its use for the plinth area, in order to build on it with the easier-to-work sandstone or brick . The splash zone required a resistant stone.
The naval construction administration in the German Reich made extensive use of Lusatian granite for construction projects for port fortifications .
plastic
In sculptural design, the rock has not found frequent use because of its strength. The force that had to be applied during processing made sculptors reach for other stones. Nevertheless, some notable uses have been passed down, for example in cemeteries in Saxony. Lusatian granite appears more frequently in tombs from around 1900 .
Apparatus construction
In precision engineering, thick slabs of the rock were used as low-vibration bases for sensitive equipment. Scales , centrifuges and other precision devices are typical for this .
Technical applications
The Lusatian granite was used for rollers in the pan mill in paper manufacture. The granite is very often found for boundary and surveying stones, bollards and earlier for signposts in Lusatia.
Agricultural purposes
The rock was used to produce rollers for field work and for well basins as well as for drinking troughs and feeding troughs for the maintenance of the cattle.
Crushing materials
Sections that could not be used for the production of ashlar were processed into gravel , chippings and packing storage . In recent times, only crushing material has been produced in the main mining area around Demitz-Thumitz .
Application examples
Antwerp
Kruyschanz lock near Antwerp
dry docks
Berlin
Deutsches Historisches Museum , floor in the foyer area of the old
Red Town Hall building , plinth area
in the 19th century, large quantities of paving slabs
Bremerhaven
Port facilities
Dresden
Albertplatz , Still Waters and Stormy Waves : two fountain basins with bronze sculptures by Robert Diez
Altmarkt , Altmarktkeller restaurant , solid columns in the
Dr.-Külz-Ring guest room , New Town Hall, main stairs and floors in the building, terrace at the Golden Gate and stairs to the
Deutsches Hygiene- ballroom Museum , portal area, external stairs and plinth at
Kreuzstraße, town hall fountain (1911) by Georg Wrba ,
Neumarkt , monument to King Friedrich August II by Ernst Julius Hähnel , only the step plinth at
Sachsenplatz , district court building , stairs and solid pillars at the main entrance
Schießgasse, police headquarters , plinth area
Theaterplatz , Sempergalerie , floor slabs in the passage to Zwingerhof
White Gasse , Gänsediebbrunnen (1876–1880) by Robert Diez
Zwinger , polished solid columns in the foyer of the Old Masters Picture Gallery,
pavement slabs in many streets and squares of the city
Heligoland
Protection systems on Heligoland
IJmuiden
Large sea lock on the North Sea Canal
Pirna
Acid towers on the former premises of the Hoesch company
Schleswig-Holstein
Lock constructions and bridges of the Kiel Canal
Stendal
Pillar of the Elbe Bridge
Others
Under the term Königshain Granite , varieties from quarries near Arnsdorf, Döbschütz, Krobnitz, Königshain and Mergelsdorf have been extracted. They have only been given the collective name Lusatian granite very rarely , although their deposits belong to the Lusatian massif.
In some deposits of the Lusatian granodiorite, dark gangue rocks appear, which are known as lamprophyres and which were and are also the target of stone mining . According to more modern petrographic points of view, a distinction is made between microgabbro and microdiorite . These varieties are not referred to as Lusatian granite, although they also occur in its deposits.
See also
literature
- Dieter Beeger: Natural stone in Dresden (= writings of the State Museum for Mineralogy and Geology in Dresden. No. 4). State Museum for Mineralogy and Geology, Dresden 1992, ISBN 3-910006-08-6 .
- Wilhelm Dienemann, Otto Burre: The usable rocks in Germany and their deposits. Volume 2: Solid Rocks. Enke, Stuttgart 1929.
- Carl Gäbert, Alexande Steuer, Karl Weiss: The usable rock deposits in Germany. Union, Berlin 1915.
- Carl Friedrich Naumann (Ed.), Bernhard Cotta : Geognostic description of the Kingdom of Saxony and the adjoining state departments. Explanations for Section VI of the geognostic chart of the Kingdom of Saxony. Arnoldische Buchhandlung, Dresden / Leipzig 1845, pp. 4–13.
- Alfred Herzog: Lusatian granite in nature and design. In: Sächsische Heimatblätter . Issue 3/1968, pp. 138-144.
- Werner Paelchen, Harald Walter (Hrsg.): Geology of Saxony. Schweizerbart, Stuttgart 2008, ISBN 978-3-510-65239-6 .
- Arnd Peschel: Natural stones. German publishing house for basic industry, Leipzig 1983.
- Hans Prescher (Hrsg.): Evidence of the geological history of Saxony. German publishing house for basic industry, Leipzig 1987, ISBN 3-342-00115-1 .
- Johannes H. Schroeder (Ed.): Natural stone in architecture and building history of Berlin. 2nd edition, self-published by Geoscientists in Berlin and Brandenburg eV, Berlin 2006, ISBN 978-3-928651-12-7 .
- Kurt Wemme, Alfred Herzog, H. Käßke: Lusatian granite. In: Sächsische Heimatblätter. Issue 3/1968, pp. 136-138.
Individual evidence
- ↑ Paelchen / Walter, Geologie , pp. 44–48.
- ↑ Paelchen / Walter, Geologie , pp. 46–47.
- ↑ Paelchen / Walter, Geologie , p. 47.
- ↑ Beeger, p. 29.
- ↑ Paul Praxl : A main source of food in this area. The history of the granite industry in Eastern Bavaria. In: Winfried Helm (Ed.): Granit. Tute Druck, Salzweg 2007, ISBN 978-3-00-023087-5 , p. 159.
- ^ Naumann / Cotta: Geognost. Charte, Section VI, 1839, p. 8.