Wealdenkohle

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Wealden coal from Barsinghausen

In Germany, Wealdenkohle is called coal that originated in the Lower Chalk (more precisely: the Berriasium ). It is named after the terrestrial Wealden facies , in whose layers the Wealden coal seams are switched on. The Wealden facies is again named after the English district of Wealden , in which such layers were first researched and described. The main deposits of Wealden coal, which has been deposited for around 5 million years, are in the Weser-Ems area and southwest of Hanover.

geology

The last period of the Middle Ages began with the Lower Cretaceous about 146 million years ago . The first 5 million year period was previously named after the English district of Wealden , today this name is only used as a facies term in geology , as the English deposits do not come from the same period as those of the Weser-Ems area, but are comparable are trained. In recent times the boundaries between the Jura and the Chalk have been adjusted several times and the German layer sequence is now placed in the Berriasium . It is also known as the Bückeburg series.

As in the Carboniferous period , there was a tropical-subtropical climate in which cypress-like trees, ginkgo gardens , conifers , ferns and palm trees grew. The whole of northern Germany was like a swamp forest.

The change between sea and land was decisive for coal formation. Since the Jura there has been a sinking trough in northern Germany, the “Lower Saxony Basin”, which was filled with brackish and continental deposits. Its southern edge was defined by a high plateau with a low mountain range, the Rheinische Masse. During the Wealden period, rivers in what is now Osnabrücker Land and south of Hanover poured sand into the basin, and clay in the eastern part. The swamp forest moors served as the basis for the coal seams that were formed .

The strata of the Wealden come to light today on the northern edge of the German low mountain range threshold in the northern Teutoburg Forest , in the northern Wiehengebirge , in the Bückeberg and on the north side of the large and small Deisters . The thickness of the Wealden varies with increasing distance from the coast between 500 m in the south and 1000 m in the north. Up to five coal seams were formed during the Wealden period. The largest deposits are east of the Weser on the Deister and north of the Weser Mountains. Coal-bearing layers of the Wealden are also part of the Osning shift of the Teutoburg Forest.

Coalification

The coaling of Wealden coal varies depending on where it was found. It ranges from the brown coal stage to the anthracite stage . The Wealden coal is the most heavily converted at Recke and Bohmte in the Osnabrück area. Bituminous layers of older layers, such as the Jura and the Carboniferous, are also heavily carbonized here ( see Schafberg (Ibbenbüren) , Piesberg ). This was caused by the Bramscher pluton .

Analyzes of the coal showed sulfur contents of 1 to 10 percent and 10 to 35 percent ash for the Wealden coal area near Wellingholzhausen and Borgloh - Oesede . All deposits are classified as fatty coal with 20 to 35 percent volatile components. The Bohmte mining area showed a sulfur content of 0.75  % by weight , ash 1.55-5% by weight and 4.2 to 10 percent volatile constituents. The occurrence is classified as anthracite . In Minden, a low-gas coal with sulfur content of 8 to 9 percent and 22 percent volatile components was extracted.

Mining areas on Wealdenkohle

The Wealden coal was mined in the Ottoschacht in Borgloh - Oesede , in the Hilterberg colliery in Bad Iburg am Limberg , the Persistence colliery in Bohmte, the Minden colliery in Minden ⊙ , the Osterwald smelter tunnel ⊙ and near Wellingholzhausen .

There were attempts in the Tecklenburger Land near Brochterbeck .

Furthermore, there was a regionally significant mining south-west of Hanover in the Deister , in the Bückeberge , in the Rehburger Mountains , in the Süntel as well as in the Osterwald and Nesselberg .

literature

  • Konrad Droste: pinging, tunnels, shafts. From coal mining in the Rehburg mountains (= district of Nienburg / Weser [Hrsg.]: Historical series of publications of the district of Nienburg / Weser . Volume 3 ). Nienburg 1987.
  • Horst Falke : The Wealden coal mining in Lower Saxony (=  publications of the Economic Society for the study of Lower Saxony's NF volume 23 ). Stalling, Oldenburg 1944.
  • Hans Röhrs : ore and coal. Mining and ironworks between Ems and Weser . Ibbenbürener Vereinsdruckerei (IVD), Ibbenbüren 1992, ISBN 3-921290-62-7 .
  • Klaus Skupin: Chalk. In: Geology in the Weser and Osnabrück Bergland. Geological Service NRW, Krefeld 2003, pp. 65–73. ISBN 3-86029-932-8
  • Wilhelm Weiland: The Schaumburg coal mines. Stadthagen 1976.

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