Carbon

from Wikipedia, the free encyclopedia
< Devonian | C arbon | Permian >
358.9–298.9 million years ago
Atmospheric O 2 share
(average over period) 		approx. 32.5% by volume
(163% of today's level)
Atmospheric CO 2 share
(average over period) 		approx. 800 ppm
(2 times today's level)
Floor temperature (average over period) approx. 14 ° C
(0 ° C above today's level)
system Subsystem step ≈ age ( mya )
higher higher higher younger
Carbon Pennsylvania Gzhelium 298.9
⬍
303.7
Kasimovium 303.7
⬍
307
Moskovium 307
⬍
315.2
Bashkirium 315.2
⬍
323.2
Mississippium Serpukhovium 323.2
⬍
330.9
Visa 330.9
⬍
346.7
Tournaisium 346.7
⬍
358.9
deeper deeper deeper older

The carbon is the fifth chronostratigraphic system or the fifth geochronological period of the Paleozoic Era in the history of the earth . Carboniferous began about 358.9 million years ago and ended about 298.9 million years ago. It is overlaid by the Permian and underlain by the Devonian .

History and naming

The carbon was introduced as a geological system (period) in England in 1822 by William Daniel Conybeare and William Phillips ( Carboniferous Series ). It is named after the coal seams that are widespread worldwide, especially in the Upper Carboniferous (Latin carbo , coal). In German-language literature, the term "(stone) coal age" is sometimes used.

Definition and GSSP

The lower limit of carbon (and simultaneously the Mississippian series and Tournaisium stage) is determined by the first appearance of Conodonten -type Siphonodella sulcata within the line of development of Siphonodella praesulcata to Siphonodella sulcata defined. The upper limit and thus the lower limit of the Permian is the first appearance of the conodont species Streptognathodus isolatus . The official reference profile of the International Commission on Stratigraphy ( Global Stratotype Section and Point , GSSP ) for the carbon is the La Serre profile in the southeastern Montagne Noire ( France ). It is a cut about 80 cm deep on the southern slope of Mount La Serre, about 125 m south of the summit (252 m) and about 525 m east of Maison La Roquette, in the area of ​​the village of Cabrières , 2.5 km northeast of the Fontès village ( Herault department , France).

Subdivision of carbon

Geological profile through the coal field near Zwickau (from Meyers Konversations-Lexikon (1885–90))

The carbon is internationally divided into two subsystems and six series with a total of seven levels.

Further subdivisions were used regionally. The Central European Carbon was divided into Dinantium ( lower carbon ) and Silesium ( upper carbon ). However, the boundary between the Central European Lower and Upper Carboniferous and the international Lower and Upper Carboniferous is different. The upper limit of the Silesium does not coincide with the international Carbon-Permian limit, but is still clearly in the Gzhelium level of the international breakdown. The Russian carbon was divided into upper, middle and lower carbon.

The biostratigraphic zoning is based mainly on marine invertebrates: goniatites (a group of ammonites ), conodonts (tooth-like hard parts of skullless chordates ), armpods (Brachiopoda), corals and large foraminifera . In the Upper Carboniferous, the biostratigraphic structure for the terrestrial (continental) deposits is partly based on land plants.

Paleogeography

The two continent masses Laurentia (North America) and Baltica (Northern Europe and Russian table) had already collided in the Silurian . This plate tectonic event is known as Caledonian orogenesis . The newly formed continent bears the name Laurussia or Old Red continent. Between Laurussia and the greater continent of Gondwana ( Africa , South America , Antarctica , Australia and India ), which lies further south, there was a sea ​​area divided by various terranes , smaller masses of continental crust. The first collisions in this area had already initiated the Variscan orogeny in the lower Devonian. In the course of the Lower Carboniferous, the convergence of Laurussia and Gondwana continued and reached its first climax at the turn of the Lower and Upper Carboniferous. This continent / continent collision is the cause of the Variscan orogeny in Europe. In the Upper Carboniferous the area between Northwest Africa and North America closed, the formation of the Appalachians came to an end. With the connection of the Siberian and Kazakhstan cratons to Laurussia (which resulted in the Ural Mountains ), all large continents were finally united in the Permian to form a supercontinent , the Pangea . The ocean surrounding Pangea is called the Panthalassa .

Climate and environment

Depiction of the giant dragonfly Meganeura from the Upper Carboniferous

The expansion of forest and marshlands reached a new maximum in the “hard coal age” of the Carboniferous. The Tournaisium (358.9 to 346.7 mya), the first chronostratigraphic stage of the Carboniferous, recorded a rise in sea level with renewed expansion of shelf seas under the conditions of a warm climate after a pronounced cooling phase at the Devonian-Carboniferous border . This warming trend flattened out at the beginning of the Middle Tournaisian and gradually passed into the climatic state of the Permocarbon Ice Age , combined with the first glaciations of the land masses lying within the southern Arctic Circle . At the beginning of the Carboniferous, the southern tip of Africa was part of the greater continent of Gondwana in the immediate vicinity of the South Pole , before the near-pole position of Antarctica was taken at the transition to the Permian . Indications of large-scale glaciations can be found in many regions of Gondwana in the form of tillites (moraine deposits) in various sedimentary horizons . This indicates a repeated change of warm and cold times .

The over millions of little altered orientation of the large continent Gondwana within the Antarctic contributed by the action of the ice-albedo feedback essential to the creation of Permokarbonen glacial age at which reached a duration of approximately 80 million years ago by the Lower Carboniferous in Medium to the Perm. A primary climate factor was also the spread of deep-rooted plants that split up the soil during the Carboniferous. The combination of increased soil erosion with extensive coalification processes removed large amounts of carbon from the atmosphere. As a result, the atmospheric CO 2 concentration fell to a hitherto unique low in the course of the Carboniferous. In contrast to this, the oxygen content in the Upper Carboniferous rose to a record value of 33 to 35 percent, but in connection with what is probably the most devastating forest and wildfire in the history of the earth, possibly with the side effect of a global smoke and haze that dampens sunlight.

About 310 million years ago the major continents Laurussia and Gondwana finally united to form the supercontinent Pangea. At the height of its expansion in Unterperm, Pangea stretched from the north polar region to the Antarctic and covered an area of ​​138 million km² including the shelf seas . Because of this huge continental barrier, the water and heat exchange of the equatorial ocean currents stalled, and the global cooling trend was further intensified. The last two stages of the Carboniferous - Gzhelium and Kasimovium - were characterized by a relatively rapid change in different climatic conditions , which were apparently largely controlled by the cyclical changes in the Earth's orbit parameters , with strongly fluctuating CO 2 concentrations from 150 to 700 ppm. Due to the 2 to 3 percent lower solar irradiation compared to today , the global average temperatures reached 12 to 14 ° C during a warm phase and were only slightly above freezing point during a glacial period. According to a 2017 study, carbon dioxide levels continued to decrease in the earliest Permian period and briefly dropped to around 100 ppm. If this assumption is confirmed, the earth system would then move into the immediate vicinity of the tipping point that would have brought the planet into the climatic state of global icing, comparable to the snowball earth events in the Neoproterozoic .

The diorama Steinkohlenwald in the Ruhr Museum illustrates the vegetation in the Carboniferous climate

In the late Carboniferous, the rainforests near the equator collapsed (referred to in technical literature as the Carboniferous Rainforest Collapse ) and with it the first mass extinction of plants. The tropical forests were decimated to a few islands of vegetation within a geologically very short period of time, and the majority of the wetlands and swamps also disappeared. Various arthropods , a large part of the amphibians ( Temnospondyli ) of that time and early reptiles with a semi-aquatic way of life were particularly affected by the loss of these biotopes . Due to the fragmentation of the habitats, the biodiversity of the terrestrial vertebrates (Tetrapoda) on the Carbon-Permian border fell significantly and initially remained low in the early Permian, before the biodiversity gradually increased again in the further course.

Landscape reconstructions of the Carboniferous are often presented in museums in the form of graphics. A life-size diorama from the Ruhr Museum in Essen gives a three-dimensional impression of a carbon black forest. An accessible model of a carboniferous landscape can be viewed in Saarland on the site of the former Landsweiler-Reden mine . In Dortmund's Rombergpark Botanical Garden, a plant show house has been dedicated to the coal forest since 1958 and makes the climate of the carbon tangible.

Development of the fauna

Aviculopecten and Syringothyris

In the Upper Devonian, two mass extinctions occurred with the Kellwasser event (372 mya) and the Hangenberg event (359 mya) taking place directly on the Devonian-Carboniferous border , in the course of which up to 75 percent of all species became extinct. This affected ammonites , brachiopods (arm pods), trilobites , conodonts , stromatopores , ostracods (mussel crustaceans) and, above all, the placodermi (armored fish). In addition, the phytoplankton was so greatly reduced that its original biodiversity was only achieved again in the Mesozoic . A number of reef builders among the corals also fell victim to the mass extinction. As a result, the number of coral reefs decreased significantly. Some scientists believe that this is why the marine ecosystems have been severely affected by prolonged oxygen shortages. This could have given impetus to the amphibian line of development. Only in the middle lower Carboniferous did a larger radiation occur again . The fossils poor time before 360-345 million years after the paleontologist Alfred Romer (Engl. As "Romer gap" Romer's Gap ), respectively.

Life in the oceans

The fossil fauna of the Carbon Sea (from Meyers Konversations-Lexikon (1885–90))

The Placodermi , the predominant group in the Devonian oceans, did not recover from the mass extinction at the turn of the Devonian / Carboniferous. The development went towards more agile forms of the ray fins . Even the trilobites , which were important key fossils since the Cambrian , only survived in the Carboniferous with a few species and lost their previous importance.

Other rock-forming groups of organisms were bryozoa (bryozoa, branched or fan-shaped, colony-forming animals) and forms of foraminifera , the large foraminifera (especially brother-in-law and Fusulina from the order of the Fusulinida ). Large foraminifera are unicellular, benthic , amoeboid creatures, but they can reach a size of 13 cm.

The ammonoids , a group of the cephalopods , developed a great diversity in the carbon. The biostratigraphy of carbon is largely based on this group. The first inner-shell cephalopods ( squid or coleoidea) appear.

Life in the country

The oldest insects (Insecta) are already known from the Lower Devonian, but whether winged insects had developed at this point is uncertain and controversial. The oldest fossils of unequivocally winged insects, with preserved wings, come from the most recent Lower Carboniferous. In the Upper Carboniferous the winged insects were already very diverse. Due to the high oxygen content of the atmosphere, giant forms formed under the insects in the course of the carbon dioxide, such as the dragonfly Meganeura . The genus Megarachne , which used to be the largest known spider, is now counted among the Eurypterids .

The Carboniferous vertebrates living on land were mainly amphibians and the first reptiles , including the Protorothyrididae . Many forms, such as Crassigyrinus , however, retained an aquatic or at least semi- aquatic way of life. The amphibians had no food competitors on land and developed various forms. Some species reached sizes of up to six meters.

The first skeletons assigned to the reptiles were found at the base of the Oberkarbon. The so-called amnion egg , with a firm outer shell and two yolk sacs, probably also developed during the Oberkarbon . Since the amnion egg is a self-contained liquid body, it means greater independence from water for reproduction.

Development of flora

Land plants of carbon in the picture of life (from Meyers Konversations-Lexikon (1885–90))

The carbon, at least the upper carbon, can also be called the age of the ferns . The world's largest reserves of hard coal arose in vast coal swamps. The prevailing representatives of the flora in the coal swamps were the genres shed trees ( Lepidodendron ) and Siegel trees ( Sigillaria ), tree-like plants that the class of lycopodiopsida are counted (Lycopodiopsida). The representatives of both genera reached sizes of up to 40 meters and trunk diameters of over one meter.

The horsetails (Equisetopsida) brought the Calamites ( Calamites also) to large tree about 20 meters out forms (usually only casts of woody Mark tubes are received by the tribes).

The group of vascular spore plants (Pteridophyta), which had already appeared in Devon, also produced tree-like forms with Glossopteris (on the then southern continent of Gondwana ). These plants showed annual rings , which is due to the Gondwana glaciation in the Upper Carboniferous.

The first representatives of the naked seed plants (gymnosperms, naked seeds ) can be detected since the Upper Carboniferous . Well-known examples of carbonic seed plants are the ferns and the needle-bearing cordaites . The also needled genera Lebachia of the Utrechtiaceae and Walchia , which belong to the Voltziales , appear only in the uppermost upper carbon. There are different opinions about the systematic classification of the two genres. B. the genus name Lebachia replaced by Utrechtia , Walchia is often listed as a genus for fossils that cannot be reliably classified (known in English as walchian conifers ). The cordaites also appear for the first time towards the end of carbon. These forest-forming conifers did not survive the mass extinction on the Permian-Triassic border . The Cordaites and the Voltcials, which died out in the Lower Jurassic, are placed among the conifers ( conifers ).

The carbon in Central Europe

Coal-limestone facies

On the southern edge of Laurussia (the continent that was formed in the Silurian by the collision of Laurentia (North America) and Baltica (Northern Europe and Russia)) sedimentation of very fossil-rich limestone occurred in the Lower Carboniferous. The area of ​​the so-called coal-limestone facies extended from Ireland / England , Belgium and the Ardennes over the slate mountains on the left bank of the Rhine to Poland. In the area of ​​England, the marine carbonate sedimentation was divided into several high zones (above all the London-Brabanter massif and the Norman threshold). Boss animals - reef limestone , rubble limestone and dark bituminous limestone were deposited . At fossils mainly bryozoans, corals are brachiopods (brachiopods) goniatites and crinoids survived. The thickness of the coal limestone reaches 300 to 700 meters and is interlocked to the south adjoining Kulm facies (see below) by reef rubble and calcareous biite.

Kulm facies

The Kulm facies adjoin the coal limestone facies to the south. It represents a synorogenic sedimentation , i.e. deposits that occurred simultaneously with the mountain formation of the Variscan orogeny. The clastic material was supplied by the Central German Kristallinschwelle , at that time an island arch. The sedimentation basin in which the Kulm facies were deposited was roughly divided into a northern and a southern area by this threshold. The northern area today forms the Rhenish Slate Mountains . In this pelvic area mainly came slate (with the bivalves clam Posidonia becheri ) and radiolarians leading chert (lydite) for deposition.

In the southern area there was a flysch facies with turbiditic sandstones , greywacke and olisthostromes . The Kulm facies in this southern basin reached thicknesses of up to 3,000 meters.

The Variscan Orogeny

The Variscan mountains are complexly built ceiling and fold mountains . The enormous shortening of the crust is noticeable in strong folds and internal thrusts. The name comes from the Variskern , a tribe based in the Vogtland . The Central European Variscan is divided into the following zones from north to south:

The first collisions of terranes (smaller masses of continental crust) took place in the Devonian. The main folding phase of the Variscan orogeny occurred at the boundary between Lower and Upper Carboniferous, also known as the Sudetic phase. Tectonic activity can be detected in the Central European Variscides up to the Permian.

Upper Carboniferous - The Post Variscan Development

During the main phase of the Variscan orogeny , large parts of Europe had become mainland and thus erosion areas. The sedimentation in the Upper Carboniferous differed fundamentally from the conditions in the Lower Carboniferous.

Subvariscis

At the edges of the Sub-Variscan Basin, a belt with extensive paralian coal swamps developed, mainly in the Westphalian region (paralian coals are formed in coastal areas: due to repeated rise and fall of the sea level, swamp areas are inundated, covered by mud and then back to mainland, so that new swamp areas are formed develop). This belt of parallel coal swamps stretched from southern England across the Ruhr area to Poland. In the Ruhr area, the Upper Carboniferous reaches a maximum thickness of 6000 meters.

literature

  • George R. McGhee Jr .: Carboniferous Giants and Mass Extinction. The Late Paleozoic Ice Age World. Columbia University Press, New York 2018, ISBN 978-0-231-18097-9 .
  • Andreas Braun: The carbon. Not just hard coal. In: Biology in Our Time. 32, 5, 2002, ISSN  0045-205X , pp. 286-293.
  • LRM Cocks , TH Torsvik: European geography in a global context from the Vendian to the end of the Palaeozoic. In: David G. Gee, Randell A. Stephenson (Eds.): European Lithosphere Dynamics. Geological Society, London 2006, ISBN 1-86239-212-9 ( Geological Society Memoir 32).
  • Peter Faupl: Historical Geology. An introduction. (= UTB for Science - Uni Pocket Books - Geosciences. 2149). 2nd, improved edition. Facultas, Vienna 2003, ISBN 3-8252-2149-0 .
  • Wolfgang Frisch , Jörg Loeschke: Plate tectonics. (= Income from research. 236). 3rd, revised edition. Wissenschaftliche Buchgesellschaft Darmstadt, 1993, ISBN 3-534-09410-7 , Chapter 10.2: Paleozoic mountain belts.
  • Felix Gradstein, Jim Ogg, Jim Smith, Alan Smith (Eds.): A Geologic timescale. Cambridge University Press, Cambridge u. a. 2004, ISBN 0-521-78673-8 .
  • Eva Paproth , Raimund Feist, Gert Flaijs: Decision on the Devonian-Carboniferous boundary stratotype. In: Episodes. 14, 4, 1991, ISSN  0705-3797 , pp. 331-336.
  • Roland Walter : Geological history, the formation of the continents and oceans. 5th edition. de Gruyter, Berlin a. a. 2003, ISBN 3-11-017697-1 .

Web links

Commons : Karbon  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Oxygen content-1000mj
  2. ↑ Phanerozoic Carbon Dioxide
  3. ↑ All palaeotemps
  4. ↑ Isabel P. Montañez, Neil J. Tabor, Deb Niemeier, William A. DiMichele, Tracy D. Frank, Christopher R. Fielding, John L. Isbell, Lauren P. Birgenheier, Michael C. Rygel: CO 2 -Forced Climate and Vegetation Instability During Late Paleozoic Deglaciation . In: Science . tape 315 , no. 5808 , January 2007, p. 87–91 , doi : 10.1126 / science.1134207 (English, online [PDF]).
  5. ↑ Alexander J. Hetherington, Joseph G. Dubrovsky, Liam Dolan: Unique Cellular Organization in the Oldest Root Meristem . In: Current Biology . tape 26 , no. June 12 , 2016, p. 1629–1633 , doi : 10.1016 / j.cub.2016.04.072 (English).
  6. ^ Peter Franks: New constraints on atmospheric CO 2 concentration for the Phanerozoic . In: Geophysical Research Letters . tape 31 , no. July 13 , 2014, doi : 10.1002 / 2014GL060457 (English, online [PDF]).
  7. ↑ ddp / bdw - Marcel Falk: Gigantism, flying and antiaging: oxygen-rich air triggered an innovation surge 300 million years ago. Earth and Space - Paleontology. In: Image of Science. Konradin Medien GmbH, June 27, 2003, accessed June 3, 2017 .
  8. ^ Andrew C. Scott: The diversification of Paleozoic fire systems and fluctuations in atmospheric oxygen concentration . In: PNAS . tape 103 , no. May 29 , 2006, p. 10861-10865 , doi : 10.1073 / pnas.0604090103 (English, online ).
  9. ↑ Peter Ward, Joe Kirschvink: A New Story of Life. How catastrophes determined the course of evolution. Deutsche Verlags-Anstalt, Munich 2016, ISBN 978-3-421-04661-1 , p. 443.
  10. ↑ Spencer G. Lucas, Joerg W. Schneider, Giuseppe Cassinis: Non-marine Permian biostratigraphy and biochronology: an introduction. In: Spencer G. Lucas, Giuseppe Cassinis, Joerg W. Schneider (Eds.): Non-Marine Permian Biostratigraphy and Biochronology. Geological Society, London, Special Publications, 265, London 2006, pp. 1-14. (PDF)
  11. ↑ Isabel P. Montañez, Jennifer C. McElwain, Christopher J. Poulsen, Joseph D. White, William A. DiMichele, Jonathan P. Wilson, Galen Griggs, Michael T. Hren: Climate, pCO 2 and terrestrial carbon cycle linkages during late Palaeozoic glacial – interglacial cycles . In: Nature Geoscience . tape 9 , no. 11 , November 2016, p. 824–828 , doi : 10.1038 / ngeo2822 (English, online [PDF]).
  12. ↑ Gerilyn S. Soreghan, Dustin E. Sweet, Nicholas G. Heaven: Upland Glaciation in Tropical Pangea: Geologic Evidence and Implications for Late Paleozoic Climate Modeling . In: The Journal of Geology . tape 122 , no. 2 , March 2014, p. 137–163 , doi : 10.1086 / 675255 (English, online [PDF]).
  13. ^ A b Georg Feulner: Formation of most of our coal brought Earth close to global glaciation . In: PNAS . tape 114 , no. 43 , October 2017, p. 11333–11337 , doi : 10.1073 / pnas.1712062114 (English).
  14. ↑ Borja Cascales-Miñana, Christopher J. Cleal: The plant fossil record reflects just two great extinction events . In: Terra Nova . tape 26 , no. 3 , 2013, p. 195-200 , doi : 10.1111 / ter.12086 .
  15. ^ William A. DiMichele, Neil J. Tabor, Dan S. Chaney, W. John Nelson: From wetlands to wet spots: Environmental tracking and the fate of Carboniferous elements in Early Permian tropical floras . In: GSA (Geological Society of America) . Special Paper 399, 2006, p. 223–248 , doi : 10.1130 / 2006.2399 (11) (English, online [PDF]).
  16. ↑ Sarda Sahney, Michael Benton, Howard J. Falcon-Lang: Rainforest collapse triggered Pennsylvanian tetrapod diversification in Euramerica . In: Geology . tape 38 , no. November 12 , 2010, p. 1079-1082 , doi : 10.1130 / G31182.1 (English, online [PDF]).
  17. ↑ Emma M. Dunne, Roger A. Close, David J. Button, Neil Brocklehurst, Daniel D. Cashmore, Graeme T. Lloyd, Richard J. Butler: Diversity change during the rise of tetrapods and the impact of the 'Carboniferous rainforest collapse ': A regional expression of a global climate perturbation . In: Proceedings of the Royal Society B (Biological Sciences) . 285, No. 1972, February 2018. doi : 10.1098 / rspb.2017.2730 .
  18. ↑ Sandra Isabella Kaiser, Ralf Thomas Becker, Thomas Steuber, Sarah Zhor Aboussalam: Climate-controlled mass extinctions, facies, and sea-level changes around the Devonian – Carboniferous boundary in the eastern Anti-Atlas (SE Morocco) . In: Palaeogeography, Palaeoclimatology, Palaeoecology . tape 310 , no. 3–4 , October 2011, pp. 340–364 , doi : 10.1016 / j.palaeo.2011.07.026 (English, online [PDF]).
  19. ↑ Marina Kloppischː Organic-geochemical comparison of selected rocks of the Frasnium / Famennium border (Oberdevon) in the Bergisches Land and the Eifel (PDF). Reports from Forschungszentrum Jülich, Institute for Chemistry and Geosphere Dynamics, 2002. (accessed April 6, 2019)
  20. ^ Carsten Brauckmann, Brigitte Brauckmann, Elke Gröning (1994, published 1996): The stratigraphical position of the oldest known Pterygota (Insecta. Carboniferous, Namurian). In: Annales de la Société géologique de Belgique. 117 (1), pp. 47-56.
  21. ^ Wilson N. Stewart, Gar W. Rothwell: Paleobotany and the Evolution of Plants. 2nd Edition. Cambridge University Press, 1993, ISBN 0-521-38294-7 .