The Hohburg Mountains: millions of years of geological history


Supervolcanism – the hot origins of the Hohburg Mountains

During the Permian period around 287 million years ago, the Wurzen region, was located south of the equator on the continent of Pangaea. For two million years, massive volcanic activity left behind a huge collapse structure (Wurzen caldera). The deposits solidified into porphyry, which can still be seen today forming the Hohburg Mountains. Around 20 to 18 million years ago, during the Tertiary period (the age of lignite formation), the waves of the Primeval North Sea crashed against these rocks. Later, the surface-near porphyry weathered to form kaolin, the “porcelain clay” used in ceramics today.
During the Ice Age (Pleistocene), the glaciers of the Northern European glaciation pushed over the Hohburg Mountains at least twice from around 350,000 years ago, giving them the “finishing touches”. The porphyry mountains sculpted by water, wind and ice are still a source of raw naterials today: the very hard and frost-resistant volcanic rock is extracted in quarries for the construction of buildings, roads and railroad lines.

Hohburg quartz porphyry – a sought-after volcanic rock

People were already using porphyry stone over 2000 years ago. At least since the 16th century, people quarried the stone for local needs in so-called farmers quarries. The rocks were either extracted manually or by using black powder. Industrial stone quarrying began on the Röcknitz Steinberg in 1887. By 1893, further quarries had been established on Spielberg, Gaudlitzberg, Zinkenberg, Frauenberg and Löbenberg. They initially supplied building and paving stones, later chippings (aggregates for asphalt roads and concrete) and ballast for railroad lines: “From stone to bread” was the name given to the industrial boom in the rural region at the time. Stone quarrying is still an important economic factor today. The quarries are natural geological monuments and evidence of industrial history.

Surveying Saxony – without satellite

Maps are an indispensable basis for every state administration and economy. The first comprehensive survey of the Electorate of Saxony was carried out by the surveyor Matthias Oeder between 1586 and 1634. This was followed by the so-called mileage sheets recorded around 1800.
Initiated by Christian August Nagel, professor of geodesy in Dresden, an area-wide (triangular) surveying network was created between 1862 and 1890 for European degree measurement and Saxon cartography. These 19th century maps were very accurate and easily stand up to comparison with today’s satellite-based maps.

GeoRoutes through “Hohburg Switzerland” – history and stories

Hohburg – also known as Hobergk or Hoburgk – has a very long history. Slavs, Elbe Germanic tribes and, from the 12th century onwards, German settlers settled here. The porphyry mountains tower 120 meters above the Mulde lowlands. This gave rise to the image of “Hohburg Switzerland”, which is also a popular tobogganing and skiing area in the Leipzig lowlands. The GeoRoutes “Bergbaupfad” (Mining Trail) and around the “Kleiner Berg” offer a hiking experience highlighting the diverse geological and industrial history.

Captions

  1.  The Wurzen eruption produced kilometer-high eruption columns of magma, ash and gas – like here at the Bromo volcano on Java (Indonesia).
  2. Geoportal Röcknitz: The exhibitions “Supervolcanoes in Saxony” and “Time Change Stone”, the GeoExperienceGarden and the volcano playground “Fred Porphyrstein“ showcase 290 million years of landscape development.
  3. Simplified profile section: illustrating the rock strata in the Hohburg Mountains.
  4. Hohburg quartz porphyry, a mineral mixture of quartz, feldspars, mica and pyroxenes.
  5. Before industrial porphyry mining: stone workers with tools in a quarry.
  6. In the Geopark Porphyry Land there are three 1st order triangulation points on prominent landmarks: On the porphyry outcrops of the Löben and Rochlitz mountains and the Collm graywacke ridge.
  7. Hohburg Hills represented on the Oeder map (section XVc, scale 1:53,333) from around 1600.
  8. Hohburg Hills shown on the Saxon mileage sheet (Berlin edition, sheet 47, scale 1:12,000) from 1806.
  9. Hohburg Hills depicted on the geological map of 1882 (Section Thallwitz); topography precisely surveyed on the surface at a scale of 1:25,000 (TK25)
  10. Hohburg Hills shown on a present-day aerial map based on free data from the Free State of Saxony, generated using satellite images.
  11. GeoRoute “Mining Trail”: 6.8 km circular route
    Kleiner Berg GeoRoute: 4.5 km circular route
    Start/finish: Geoportal Steinarbeiterhaus Hohburg
    Routes are not barrier-free
  12. scouring marks on the Naumann-Heim rock on the Kleiner Berg produced by the katabatic winds blowing out from the ice-age glacier.
  13. Zinkenberg quarry: industrial quartz porphyry mining since 1893.

Timeline

  • Present: Discontinuous porphyry mining only at Frauenberg and Zinkenberg
  • 2016: Museum Steinarbeiterhaus, founded in 1985, is the geoportal to the Geopark Porphyry Land
  • 1958: Closure of the quarry on Löbenberg
  • The quarry on the south side of the Löbenberg was in operation from 1892 to 1902, the western quarry from 1927 to 1958.
  • 1932-34: Gravel works conversion and construction of a new chippings plant on the Zinkenberg
  • 1908: Electrification of the quarry facilities at Frauenberg
  • 1901-65: Kaolin mining near Kapsdorf (today: Kaolinsee)
  • 1899: Foundation of the Hohburger Quarz-Porphyr-Werke AG Röcknitz
  • 1896: Railway connection for the quarries at Steinberg, Gaudlitzberg and Zinkenberg
  • 1890-93: industrially operated quarries on Gaudlitzberg, Zinkenberg (photo), Spielberg, Frauenberg and Löbenberg
  • 1887: Start of industrial stone quarrying on the Röcknitzer Steinberg
  • 1880: Farmers‘ quarry on the Löbenberg closed
  • 1868: Erection of the “Triangulation column 1st class” on the Löbenberg by the geodesist Ch. A. Nagel
  • 1844: C. F. Naumann, geologist from Leipzig, discovers “Fels-Schliffe” and describes them as glacial striations of the northern European inland glaciation
  • 1802: Building of the Stoneworker’s house, today museum and geoportal Hohburg
  • 1185: earliest record of the village of Hohburg (Hoberch) in a document
  • 10th/11th century: farmstead on today’s Hohburg Kirchberg
  • 9th/10th century: early medieval imperial castle on the Kleiner Berg
  • 2nd century BC: Additional fortification on the Burzelberg; porphyry stone used as grinding stones and tapping stones
  • 5th/4th century BC: Early Iron Age castle on the Burzelberg; protective walls made of porphyry rock, pottery from the Laténe culture
  • 12,000 years BC: resting places of Palaeolithic hunters and gatherers on the Burzelberg

Imprint

  • Concept and texts in cooperation with Geoportal Steinarbeiterhaus Hohburg & Nachbar- und Traditionsverein Hohburger Berge e.V.
  • Plans/maps/photos: Archive Museum Steinarbeiterhaus Hohburg, Archive Nachbar- und Traditionsverein Hohburger Berge e.V., Geopark Porphyrland e.V., MaPix Fotographie Grimma, Ralf Schubert, Deutsche Fotothek Dresden, Dr. Richard Roscoe
  • Geological section/route map: GEOmontan GmbH Freiberg according to GK50 1992, Rascher et al.2004, Rast 1964 & Landesvermessungsamt Sachsen
  • Design: Lars Hoschkara, DESIGN & MULTIMEDIA (Wermsdorf)