Iron sandstone formation
Abbreviations:
The iron sandstone formation is a lithostratigraphic formation of the southern German Jura . It is underlain by the Opalinus Clay Formation and overlaid by the Sengenthal Formation and the Wedelsandstone Formation . In Baden-Wuerttemberg it interlocks to the west with the Eichberg formation . It has a maximum thickness of up to 60 m and is dated to the Oberaalenium .
history
The term iron sandstone as a name for these deposits was mainly used in Franconia . Since these deposits in Franconia do not differ significantly lithostratigraphically from the simultaneous deposits in Baden-Württemberg, the term was extended to East Württemberg by Gert Bloos, Gerd Dietl and Günter Schweigert in 2005 and defined as a formation.
definition
The iron sandstone formation consists of mighty sandstones , in which z. Some iron ore seams that were mined earlier are stored. The basis of the formation is the so-called Comptum Bank, which is missing further to the east. Here the base is formed by the Lower Donzdorf sandstone. The upper limit is the top of the Upper Donzdorf sandstone or the base of the Sowerbyi oolite, which already belongs to the Wedelsandstone formation above. It interlocks to the west with the Eichberg formation.
Temporal scope and distribution area
The iron sandstone formation is dated to the Upper Aalenium and is widespread in East Württemberg and North Bavaria.
Breakdown
The iron sandstone formation in East Wuerttemberg can be subdivided into the lower Donzdorf sandstone, the personat or actual iron sandstone and the upper Donzdorf sandstone. A formal breakdown into subformations has not yet been published. The personate sandstones are named after the shell Pecten personatus , today's name Paramussium pumilum . Unterer and Ober Donzdofer sandstone are named after the town of Donzdorf in the district of Göppingen (Baden-Württemberg).
Mining
The iron sandstone formation contains, as the name suggests, sandstones containing iron oxide. The iron is contained in iron oxides , which were locally washed together in greater thicknesses. In East Württemberg, two seams with a thickness of 1.4 and 1.7 m were mined from 1365 to 1948. The seams have between 21 and 42% iron content and 26 to 31% silica content. This high silica content is very unfavorable for smelting. After the war, mining had to be stopped first because of a lack of coal and later for reasons of profitability.
Natural stone
The sandstones of the iron sandstone formation were formerly also mined for the production of stone. The Ulm Minster was mainly built from Donzdorf sandstone .
literature
- Gert Bloos, Gerd Dietl & Günter Schweigert: The Jura of Southern Germany in the Stratigraphic Table of Germany 2002. Newsletter on Stratigraphy, 41 (1-3): 263-277, Stuttgart 2005 ISSN 0078-0421
Web links
- German Stratigraphic Commission (Ed.): Stratigraphische Tisch von Deutschland 2002 . Potsdam 2002, ISBN 3-00-010197-7 . (PDF; 6.57 MB)
- Middle Jura in Baden-Württemberg (PDF; 20.5 kB)
Individual evidence
- ^ Karlheinz Bauer: Geology: A short summary. ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. Tiefer Stollen visitor mine , Aalen
- ↑ Natural stone in Baden-Württemberg. ( Memento from September 4, 2012 in the web archive archive.today ) State Office for Geology, Raw Materials and Mining, Baden-Württemberg
