Geology in Stolberg (Rhld.)
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The geology in the urban area of Stolberg (Rhld.) In the urban region of Aachen offers an outline through parts of the earth's history from southeast to northwest, which can best be observed in the valley of the Vichtbach .
Geological location
The city is located on the edge of the Rhenish Slate Mountains in the Lower Rhine or Cologne Bay , one of three main earthquake areas in Germany . The sediments , which were deposited in a horizontal sequence of layers during multiple sea invasions, lifted the folding of the Eifel towards the mountains. The geology of the Lower Rhine Bay bordering to the north differs significantly from the subsoil in the Stolberg area, because further north there are loose sediments that were created there by subsidence movements over the past 30 million years. The geological treasure trove forms the prerequisite for the diversity of the Stolberg nature with partly endemic species, such as the Galmeifluren and limestone grasslands - and has shaped the city's economy to this day.
Mineral deposits
In addition to iron ore and lead , various ore minerals can be found in the coal-lime layers, including zinc compounds such as zinc blende , shell blende , goslarite, hydrozincite and smithsonite (near Breinigerberg , Diepenlinchen and Eschweiler-Hastenrath ), lead compounds such as galena , cerussite and pyromorphite , the lead-iron compound James , Iron compounds such as marcasite , pyrite , limonite and manganosiderite as well as copper compounds such as copper pyrites and malachite . The calcium minerals calcite and dolomite and the silicon compound quartz as tiny smoky quartz and morione are not ore minerals .
Rock layers
Cambrian
The oldest rocks in the southwest come from the Cambrian approx. 500 million years ago and are mostly covered by forest. Only Schevenhütte is in this area. The dark slate of today's Vennrücken was created from the fine clay sludge .
Devon
Middle Devonian
The Vicht conglomerate comes from the middle Devonian and consists of egg- to fist-sized quartz and quartzite elements as well as sand banks. Its thickness varies from a few to 21 meters, according to other sources even 50 meters. It forms the natural monument Kluckensteine and is a poorly sorted fanglomerate that forms a prominent cliff and can be assigned to the lower Eifel level due to plant finds. The entire gravel bank extends to Eupen with a thickness of 10 to 80 meters . With the exception of the settlements of Zweifall , Vicht and Gressenich , the clays and sands of the Devonian are also largely covered by the Eifel forest.
Upper Devonian
The tree line coincides in the south with the border to the next geological layer. These are the deposits of mass limestone and dolomite from the turn from the Middle to the Upper Devonian 380 million years ago, which extend in a narrow strip from Venwegen via Breinig , Breinigerberg and Mausbach further to the northeast on Werth and are the remains of a coral reef , which was formed by rock-forming organisms in a shallow sea divided by islands and lagoons . These thick-shelled brachiopods , corals , knotty and bulbous stromatopores and calcareous algae are preserved as fossils in some banks . The Schomet in Breinig is an area that is characterized by a high wealth of fossils . Due to the folding , the 500 m thick deposit from the Devonian alternates three times on the line from Dorff , Breinig, Breinigerbergb, Büsbach , Mausbach to Werth with the mighty limestone banks of the Undercarbons.
Carbon
Lower carbon
These layers, which were created in the Lower Carboniferous 350 to 325 years ago, are misleadingly referred to as coal limestone , since geologically they do not contain any coal, but only formed in the Carboniferous. Relics of sulphate minerals in it suggest the deposition of evaporites . The oolite in the Upper Coal Limestone, which was created from millimeter-sized lime spheres that were ground round by the surf of the coral reef at that time , forms the rocks of the Jungfernstein in the NSG Bernhardshammer and Stolberg Castle, faded white .
Upper carbon
In the Upper Karbon until 280 million years ago the Upper and Lower Stolberg Strata were formed, which extend from Münsterbusch via Oberstolberg to Donnerberg . 2000 m of clay were deposited in alternating coastlines. The Gedauer conglomerate is best open on the upper reaches of the Inde and shows itself in the area of the corridor of the same name Tatternsteine nature reserve with valley floodplain as a steep wall covering the entire valley slope, which is popularly known as Tatternsteine. Today's coal seams emerged from extensive coastal moors after being covered . The occurrences of the Lower Stolberg Strata on the Liester and in Oberstolberg were insignificant , while the Upper Stolberg Strata in Münsterbusch and on the Birkengang contain some of the Eschweiler mining seams that were once worth mining . The entire sequence of layers up to the Upper Carboniferous was formed into a fold mountains by the Variscan mountain range . Ore minerals rose up here and crystallized out, especially in cracks in the coal-limestone layers.
literature
- Ulrich Haese: Nature conservation in an industrial city , Rhenish landscapes 31, Neuss 1987.
- Karl-Heinz Ribbert: Geology in the Rhenish Slate Mountains - Part 1 North Eifel , Geological Service NRW, Krefeld 2010, ISBN 978-3-86029-934-0 , 183 pp.