The Kupferschiefer (German language for Copper Shale, Copper Schist or Copper Slate)[ or Kupfermergel (Copper Marl), (T1 or Z1)][ is an extensive and remarkable sedimentary unit in Central Europe. The relatively monotonous succession is typically and maximum thick, but extends over an area of across the Southern Permian Basin. The Kupferschiefer can be found in outcrop or in the subsurface straddling six countries, including parts of the southern North Sea. The lateral equivalent outcropping in England is called Marl Slate.
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Despite its distinctive nature, the Kupferschiefer is not ranked as a formation but is officially declared a sub-unit of the Werra Formation, the lowest formation of the Zechstein Group, overlying the Rotliegend Group. The unit has been dated to 257.3 ± 1.6 Ma, placing it in the Wuchiapingian stage of the Permian.
The Kupferschiefer comprises , bituminous , and deposited mostly in an open marine setting, with the borders of its extension deposited in a shallow marine environment. At time of deposition, the area what is now northern Europe was covered by an enclosed sea; the Zechstein sea, characterized by anoxic waters conditions.
The Kupferschiefer is renowned for hosting one of the most important copper deposits in the world, which were mined at least since 1199 AD. Other mineral resources found in the unit include zinc, vanadium, lead and silver.
The Kupferschiefer is also an important lagerstätte; having provided fossils of early Archosauromorpha , the ancestors to modern and extinct , as well as , many fossil fish, including Coelacanthus, Dorypterus and Palaeoniscum, flora and other fossils. Famous finds from the unit include Parasaurus, Protorosaurus, Weigeltisaurus jaekeli and Glaurung schneideri.
Description
The Kupferschiefer is a regional stratigraphic unit stretching across an area of in the Southern Permian Basin of north-central Europe. The unit is typically thick. In the Rossenray 2 shaft, the unit reaches a maximum thickness of .[Bachmayer & Malzahn, 1983, p.101] The Kupferschiefer unconformably overlies various formations of the Rotliegend Group and the Variscan orogeny and forms the basal unit of the Zechstein Group.[Paleo-ecosystems, p.2] In some parts of the Zechstein Basin, the Kupferschiefer is underlain by the Mutterflöz Limestone, an organic-lean thin limestone unit.[ Despite its distinctive nature, the Kupferschiefer is not ranked as a formation but is officially declared a sub-unit of the Werra Formation, the lowest formation of the Zechstein Group. The Kupferschiefer is overlain by the Zechstein Limestone sub-unit of the Werra Formation.][
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The unit has been dated to 257.3 ± 1.6 Ma, placing it in the Wuchiapingian stage of the Permian.[Ezcurra et al., 2014b] The age of the unit corresponds to the Ilinskoe part of the Sokolki Assemblage Zone of European Russia and the Tropidostoma Assemblage Zone of the Karoo Basin of South Africa.[Tsuji & Müller, 2008, p.1112]
The Kupferschiefer contains up to 30% organic matter,[ with variations across its extent. The basinal facies shows values of between 5 and 25% TOC, while the marginal facies present values up to 7% TOC and swell facies are much poorer in organic matter with values below 1%.][Paleo-ecosystems, p.22]
Basin history
Depositional environment
The Kupferschiefer was deposited in a highstand setting,[Paleo-ecosystems, p.4] in a deep enclosed basin, covered by the Zechstein sea that was present on the paleocontinent Laurussia, the northern part of Pangea.[Paleo-ecosystems, p.7] The basin possibly had periodic connections to the Paleo-Tethys Ocean.[Paleo-ecosystems, p.6] Sedimentation rates during Kupferschiefer deposition were low, estimated at per thousand years.[ Schwarzer Philipp at Fossilworks.org]
The climate of the Late Permian was extremely variable, with polar icecaps present near the south pole and hot and arid conditions prevailing in the tropic and paleotemperate regions of the northern and southern hemispheres.[Paleo-ecosystems, p.9] The Zechstein sea in the Late Permian was located at paleolatitudes around 15 to 16 degrees north.[ Large areas of Pangea were covered by and arid conditions also prevailed near the Zechstein sea of the time.][Paleo-ecosystems, p.10]
Apatite oxygen isotope analysis has revealed that the Late Permian was characterized by a drastic increase in global temperatures, accompanied by a strong rise of eustatic sea level. The rise in oxygen isotope values was possibly related to an increase in volcanic activity.[Paleo-ecosystems, p.11] The Permian-Triassic extinction event, the biggest extinction event in geologic history, is thought to have been caused mostly by large volcanic provinces of the Siberian Traps.
Mining
Prehistoric finds of slag and bronze from smelting sites on top of or immediately adjacent to outcropping Kupferschiefer ores at Wettelrode, Mohrungen, and Bottendorf in Central Germany evidence Early to Middle Bronze Age mining of the Kupferschiefer ores. The medieval mining history of the Kupferschiefer ores is documented in written sources since at least 1199 A.D. from the Mansfeld district in Central Germany. The Counts of Mansfeld developed several copper mines, smelters, and a mint at the town of Eisleben, where copper and silver coins were minted from the metals of the Kupferschiefer ores.[Borg et al., 2012, p.457]
Germany
The main mining district of the Kupferschiefer in Germany was Mansfeld Land, which operated from at least 1199 AD,[ and has provided 2,009,800 tonnes of copper and 11,111 tonnes of silver.][Borg et al., 2012, p.458] The Mansfeld mining district was exhausted in 1990.[Borg et al., 2012, p.455][Borg et al., 2012, p.475]
Eisleben in the Mansfeld Land is the type locality of two minerals;[ Eisleben, Mansfeld at Mindat.org] the nickel-arsenate maucherite,[ Maucherite at Mindat.org] and betekhtinite, a copper-lead-iron sulfide.[ Betekhtinite at Mindat.org] The latter mineral has a co-type locality in the Ernst-Thälmann shaft, that operated from 1906 to 1962 and produced 260,000 tons of copper; about 10% of the overall production from the Mansfeld area.[ Ernst-Thälmann shaft, Mansfeld at Mindat.org]
Many minerals have been found in the Sangerhausen district of Saxony-Anhalt,[ Copper slate deposits, Sangerhausen at Mindat.org][ Bernard Koenen shafts I and II, Copper slate deposits, Sangerhausen at Mindat.org] which produced 619,200 tonnes of copper and 3,102 tonnes of silver as of 2012, with 860,000; respectively 4,650 tonnes as remaining proven reserves.[
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In the Spremberg-Graustein-Schleife mining area, stretching across the Brandenburg district Spree-Neiße and Görlitz in Saxony, the Kupferschiefer is estimated to contain 130 million tonnes of ore, of which 1,486,000 tonnes of copper,[ with a copper content of 1.47%. The mining district is about and the copper-bearing beds lie at a depth between .][ KSL Kupferschiefer Lausitz GmbH]
The Kupferschiefer contains up to 3% copper, 10 ppm of platina and up to 3000 ppm gold.[ Drama im Kupferschiefermeer]
The "Im Lochborn" mine, mining from the Kupferschiefer,[Borg et al., 2012, p.456] located in Bieber, Hessen is the type locality of the mineral bieberite,[ "Im Lochborn" mine, Bieber, Hessen at Mindat.org] a cobalt sulfate named after the location.[ Bieberite at Mindat.org] The mineral rösslerite, a magnesium arsenate, also has the mine as type locality.[ Rösslerite at Mindat.org]
Poland
Two main Kupferschiefer mining areas in Poland are the North-Sudetic trough, with 212,894 tonnes of copper and 756.7 tonnes of silver mined as of 2012 and an estimated remaining reserves of 1,460,000 tonnes of copper, and the Fore-Sudetic monocline, with more than 20,000,000 tonnes of copper and more than 14,085 tonnes of silver mined since 1949. Main mining districts in Poland are the Głogów industrial district, the Lubichów and Grodziec fields, and the Konrad, Lena, Lubin, Nowy Kosciół, Polkowice, Rudna and Sieroszowice mines.[ The latter mine][ Sieroszowice mine at Mindat.org] is the type locality for the silver-quicksilver amalgame, eugenite.[ Eugenite at Mindat.org] The Polkowice mine is the type locality for two rare lead and germanium-bearing sulfide minerals;[ Polkowice mine at Mindat.org] polkovicite, named after the mine,[ Polkovicite at Mindat.org] and morozeviczite.[ Morozeviczite at Mindat.org]
Paleontological significance
The Kupferschiefer has provided unique fossils of an early reptile; Protorosaurus belonging to the Archosauromorpha, as well as , fish, an insect and fossil flora.
As of 2014, at least 28 Protorosaurus speneri specimens are known from the Kupferschiefer in the states of Thuringia and Hesse in central Germany.[Ezcurra et al., 2014a, p.7] The type locality for the species is Glücksbrunn, Heidelberg, near Schweina in Thuringia.[ Glücksbrunn/Heidelberg near Schweina at Fossilworks.org][Ezcurra, 2016, p.22] The type locality for Parasaurus is Walkenried in Lower Saxony.[Tsuji & Müller, 2008][ Walkenried at Fossilworks.org] Fossils of both species were found containing quartz pebbles in their guts.[Munk & Kues, 1993, p.171][Munk & Kues, 1993, p.172]
Fossil fish of the species are abundantly found in different locations in the Kupferschiefer. The species epithet of the "Eisleben Shale Fish", or "Kupferschiefer Herring" refers to Johann Karl Freiesleben, the (mining inspection director) of Saxony.[ Palaeoniscum freieslebeni at Museum Schloss Bernburg] Other fish found in the Kupferschiefer include Coelacanthus, Hopleacanthus, Acentrophorus, Menaspis, Muensterichthys, Platysomus, and two species of Janassa and Wodnika.
Fossil content
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[Weichelt, 1930] |
[Bulanov & Sennikov, 2015, p.1357] |
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[ Richelsdorf (Althaus collection) at Fossilworks.org] |
[ Wolfsberg pit at Fossilworks.org] |
[ Mansfeld, Dresden collection at Fossilworks.org][ Freieslebenschacht at Fossilworks.org][Brandt, 2009, p.16] |
[ Lonau at Fossilworks.org] |
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[ Hasbergen Excavation Planum II at Fossilworks.org] |
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[ Bodental at Fossilworks.org] |
[ Hasbergen Excavation Planum I at Fossilworks.org] |
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[ Hasbergen Excavation Planum III at Fossilworks.org] |
[ Richelsdorf Mountains at Fossilworks.org] |
[Guthörl, 1965, p.229][ Rossenray 2 Shaft, 415 m depth, Kamp-Lintfort at Fossilworks.org] |
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[ Merzenberg, near Milbitz at Fossilworks.org] |
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[Bauer et al., 2013, p.546] |
[Bauer et al., 2013, p.549] |
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[Grebe, 1957][ Kupferschiefer 450 m floor Friedrich Heinrich Mine Kamp-Lintfort Germany at Fossilworks.org] |
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Geologic maps
Zechstein in blue
File:Geomap Rhoen.jpg|Rhoen
File:Thuringian Forest Geology.png|Thuringian Forest
File:Geomap Thur-Franc-Vogtl-SM.png|Thuringian-Franconian mountains
File:Elm Asse Dorm geol.png|Eastern Brunswick
See also
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List of fossiliferous stratigraphic units in Denmark
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List of fossiliferous stratigraphic units in Germany
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List of fossiliferous stratigraphic units in the Netherlands
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List of fossiliferous stratigraphic units in Poland
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Rio do Rasto Formation, contemporaneous fossiliferous formation of the Paraná Basin, Brazil
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Copperfields Mine of Canada
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Copper Country of Michigan
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Chuquicamata of Chile
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Copperbelt Province of Zambia
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Old Adaminaby and Lake Eucumbene of Australia
Bibliography
- Geology
- Paleontology
External links
