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Permian Period
299 - 251 million years ago
P
LatePermianGlobal.jpg
Mean atmospheric O2 content over period duration ca. 23 Vol %[1]
(115 % of modern level)
Mean atmospheric CO2 content over period duration ca. 900 ppm[2]
(3 times pre-industrial level)
Mean surface temperature over period duration ca. 16 °C [3]
(2 °C above modern level)
Sea level (above present day) Relatively constant at 60m in early Permian; plummeting during the middle Permian to a constant −20 m in the late Permian.[4]
Key events in the Permian
view • discuss • edit
-300 —
-295 —
-290 —
-285 —
-280 —
-275 —
-270 —
-265 —
-260 —
-255 —
-250 —
P
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Mesozoic
Palæozoic
Lopingian (Upper Permian)
Guadalupian (Middle Permian)
Cisuralian (Lower Permian)
An approximate timescale of key Permian events.
Axis scale: millions of years ago.

The Permian[note 1] is a geologic period and system characterized among land vertebrates by the diversification of the early amniotes into the ancestral groups of the mammals, turtles, lepidosaurs and archosaurs. The Permian Period follows the Carboniferous and extends from 299.0 ± 0.8 to 251.0 ± 0.4 Ma (million years before the present). It is the last period of the Paleozoic Era and famous for its ending epoch event, the largest mass extinction known to science. The Permian Period was named after the kingdom of Permia in modern-day Russia by Scottish geologist Roderick Murchison in 1841 (not the city of Perm, as commonly misconstrued).

Contents

ICS Subdivisions

Official (ICS, 2004)[5] Subdivisions of the Permian System, from most recent to most ancient rock layers are:

Upper Permian (Late Permian) or Lopingian, Tatarian, or Zechstein, epoch [260.4 ± 0.7 Ma - 251.0 ± 0.4 Ma][6]:
  • Changhsingian (Changxingian) [253.8 ± 0.7 Ma - 251.0 ± 0.4 Ma]
  • Wuchiapingian (Wujiapingian) [260.4 ± 0.7 Ma - 253.8 ± 0.7 Ma]
  • Others:
    • Waiitian (New Zealand) [260.4 ± 0.7 Ma - 253.8 ± 0.7 Ma]
    • Makabewan (New Zealand) [253.8 - 251.0 ± 0.4 Ma]
    • Ochoan (North American) [260.4 ± 0.7 Ma - 251.0 ± 0.4 Ma]
Middle Permian, or Guadalupian epoch [270.6 ± 0.7 - 260.4 ± 0.7 Ma][7]:
  • Capitanian stage [265.8 ± 0.7 - 260.4 ± 0.7 Ma]
  • Wordian stage [268.0 ± 0.7 - 265.8 ± 0.7 Ma]
  • Roadian stage [270.6 ± 0.7 - 268.0 ± 0.7 Ma]
  • Others:
    • Kazanian or Maokovian (European) [270.6 ± 0.7 - 260.4 ± 0.7 Ma][8]
    • Braxtonian stage (New Zealand) [270.6 ± 0.7 - 260.4 ± 0.7 Ma]
Lower / Early Permian or Cisuralian epoch [299.0 ± 0.8 - 270.6 ± 0.7 Ma][9]:
  • Kungurian (Irenian / Filippovian / Leonard) stage [275.6 ± 0.7 - 270.6 ± 0.7 Ma]
  • Artinskian (Baigendzinian / Aktastinian) stage [284.4 ± 0.7 - 275.6 ± 0.7 Ma]
  • Sakmarian (Sterlitamakian / Tastubian / Leonard / Wolfcamp) stage [294.6 ± 0.8 - 284.4 ± 0.7 Ma]
  • Asselian (Krumaian / Uskalikian / Surenian / Wolfcamp) stage [299.0 ± 0.8 - 294.6 ± 0.8 Ma]
  • Others:
    • Telfordian (New Zealand) [289 - 278]
    • Mangapirian (New Zealand) [278 - 270.6]

Oceans

Sea levels in the Permian remained generally low, and near-shore environments were limited by the collection of almost all major landmasses into a single continent -- Pangaea. This could have in part caused the widespread extinctions of marine species at the end of the period by severely reducing shallow coastal areas preferred by many marine organisms.

Paleogeography

Geography of the Permian world

During the Permian, all the Earth's major land masses except portions of East Asia were collected into a single supercontinent known as Pangaea. Pangaea straddled the equator and extended toward the poles, with a corresponding effect on ocean currents in the single great ocean ("Panthalassa", the "universal sea"), and the Paleo-Tethys Ocean, a large ocean that was between Asia and Gondwana. The Cimmeria continent rifted away from Gondwana and drifted north to Laurasia, causing the Paleo-Tethys to shrink. A new ocean was growing on its southern end, the Tethys Ocean, an ocean that would dominate much of the Mesozoic Era. Large continental landmasses create climates with extreme variations of heat and cold ("continental climate") and monsoon conditions with highly seasonal rainfall patterns. Deserts seem to have been widespread on Pangaea. Such dry conditions favored gymnosperms, plants with seeds enclosed in a protective cover, over plants such as ferns that disperse spores. The first modern trees (conifers, ginkgos and cycads) appeared in the Permian.

Three general areas are especially noted for their extensive Permian deposits - the Ural Mountains (where Perm itself is located), China, and the southwest of North America, where the Permian Basin in the U.S. state of Texas is so named because it has one of the thickest deposits of Permian rocks in the world.

Climate

The climate in the Permian was quite varied. At the start of the Permian, the Earth was still at the grip of an Ice Age from the Carboniferous. Oxygen levels decreased, wiping out plant life and some of the giant insects from the Carboniferous[10]. Glaciers receded around the mid-Permian period as the climate gradually warmed, drying the continent's interiors[10]. In the late Permian period, the drying continued although the temperature cycled between warm and cool cycles [10].

Life

Dimetrodon and Eryops- Early Permian, North America
Ocher fauna - Early Middle Permian, Ural Region
Titanophoneus and Ulemosaurus - Ural Region

Marine biota

Permian marine deposits are rich in fossil mollusks, echinoderms, and brachiopods. Fossilized shells of two kinds of invertebrates are widely used to identify Permian strata and correlate them between sites: fusulinids, a kind of shelled amoeba-like protist that is one of the foraminiferans, and ammonoids, shelled cephalopods that are distant relatives of the modern nautilus. By the close of the Permian, trilobites and a host of other marine groups became extinct.

Terrestrial biota

Edaphosaurus pogonias - Early Permian

Terrestrial life in the Permian included diverse plants, fungi, arthropods, and various types of tetrapods. The period saw a massive desert covering the interior of the Pangaea. The warm zone spread in the northern hemisphere, where extensive dry desert appeared. The rocks formed at that time were stained red by iron oxides, the result of intense heating by the sun of a surface devoid of vegetation cover. A number of older types of plants and animals died out or became marginal elements.

The Permian began with the Carboniferous flora still flourishing. About the middle of the Permian a major transition in vegetation began. The swamp-loving lycopod trees of the Carboniferous, such as Lepidodendron and Sigillaria, were progressively replaced in the continental interior by the more advanced seed ferns and early conifers. At the close of the Permian, lycopod and equicete swamps reminiscent of Carboniferous flora was relegated to a series of equatorial islands in the Paleotethys Sea that later would become the South China.[11]

The Permian saw the radiation of many important conifer groups, including the ancestors of many present-day families. Rich forests were present in many areas, with a diverse mix of plant groups. The southern continent saw extensive seed fern forests of the Glossopteris flora. Oxygen levels were probably high there. The ginkgos and cycads also appeared during this period.

Insects of the Permian

By the Pennsylvanian and well into the Permian, by far the most successful were primitive relatives of cockroaches. Six fast legs, two well developed folding wings, fairly good eyes, long, well developed antennae (olfactory), an omnivorous digestive system, a receptacle for storing sperm, a chitin skeleton that could support and protect, as well as form of gizzard and efficient mouth parts, gave it formidable advantages over other herbivorous animals. About 90% of insects were cockroach-like insects ("Blattopterans").[12]

The dragonflies Odonata were the dominant aerial predator and probably dominated terrestrial insect predation as well. True Odonata appeared in the Permian[13][14] and all are amphibious. Their prototypes are the oldest winged fossils,[15] go back to the Devonian, and are different from other wings in every way.[16] Their prototypes may have had the beginnings of many modern attributes even by late Carboniferous and it is possible that they even captured small vertebrates, for some species had a wing span of 71 cm.[17] A number of important new insect groups appeared at this time, including the Coleoptera (beetles) and Diptera (flies).

Reptile and amphibian fauna

Early Permian terrestrial faunas were dominated by pelycosaurs and amphibians, the middle Permian by primitive therapsids such as the dinocephalia, and the late Permian by more advanced therapsids such as gorgonopsians and dicynodonts. Towards the very end of the Permian the first archosaurs appeared, a group that would give rise to the dinosaurs in the following period. Also appearing at the end of the Permian were the first cynodonts, which would go on to evolve into mammals during the Triassic. Another group of therapsids, the therocephalians (such as Trochosaurus), arose in the Middle Permian. There were no aerial vertebrates.

The Permian period saw the development of a fully terrestrial fauna and the appearance of the first large herbivores and carnivores. It was the high tide of the anapsides in the form of the massive Pareiasaurs and host of smaller, generally lizard-like groups. A group of small reptiles, the diapsids started to abound. These were the ancestors to most modern reptiles and the ruling dinosaurs as well as pterosaurs and crocodiles.

Thriving also, were the early ancestors to mammals, the synapsida, which included some large reptiles such as Dimetrodon. Reptiles grew to dominance among vertebrates, because their special adaptations enabled them to flourish in the drier climate.

Permian amphibians consisted of temnospondyli, lepospondyli and batrachosaurs.

Permian–Triassic extinction event

The Permian–Triassic extinction event, labeled "End P" here, is the most significant extinction event in this plot for marine genera which produce large numbers of fossils.

The Permian ended with the most extensive extinction event recorded in paleontology: the Permian-Triassic extinction event. 90% to 95% of marine species became extinct, as well as 70% of all land organisms. It is also the only known mass extinction of insects.[18][19][20] On an individual level, perhaps as many as 99.5% of separate organisms died as a result of the event[21]. Recovery from the Permian-Triassic extinction event was protracted; on land ecosystems took 30M years to recover[22].

There is also significant evidence that massive flood basalt eruptions from magma output lasting thousands of years in what is now the Siberian Traps contributed to environmental stress leading to mass extinction. The reduced coastal habitat and highly increased aridity probably also contributed. Based on the amount of lava estimated to have been produced during this period, the worst-case scenario is an expulsion of enough carbon dioxide from the eruptions to raise world temperatures five degrees Celsius[10].

Another hypothesis involves ocean venting of hydrogen sulfide gas. Portions of deep ocean will periodically lose all of their dissolved oxygen allowing bacteria that live without oxygen to flourish and produce hydrogen sulfide gas. If enough hydrogen sulfide accumulates in an anoxic zone, the gas can rise into the atmosphere.

Oxidizing gases in the atmosphere would destroy the toxic gas, but the hydrogen sulfide would soon consume all of the atmospheric gas available to change it. Hydrogen sulfide levels would increase dramatically over a few hundred years.

Modeling of such an event indicates that the gas would destroy ozone in the upper atmosphere allowing ultraviolet radiation to kill off species that had survived the toxic gas (Kump, et al., 2005). Of course, there are species that can metabolize hydrogen sulfide.

Another hypothesis builds on the flood basalt eruption theory. Five degrees Celsius would not be enough increase in world temperatures to explain the death of 95% of life. But such warming could slowly raise ocean temperatures until frozen methane reservoirs below the ocean floor near coastlines (a current target for a new energy source) melted, expelling enough methane, among the most potent greenhouse gases, into the atmosphere to raise world temperatures an additional five degrees Celsius. The frozen methane hypothesis helps explain the increase in carbon-12 levels midway into the Permian-Triassic boundary layer. It also helps explain why the first phase of the layer's extinctions was land-based, the second was marine-based (and starting right after the increase in C-12 levels), and the third land-based again.

An even more speculative hypothesis is that intense radiation from a nearby supernova was responsible for the extinctions.

Trilobites, which had thrived since Cambrian times, finally became extinct before the end of the Permian.

Nautiluses, a species of cephalopods, surprisingly survived this occurrence.

In 2006, a group of American scientists from Ohio State University reported evidence for a possible huge meteorite crater (Wilkes Land crater) with a diameter of around 500 kilometers in Antarctica. The crater is located at a depth of 1.6 kilometers beneath the ice of Wilkes Land in eastern Antarctica. The scientists speculate that this impact may have caused the Permian–Triassic extinction event, although its age is bracketed only between 100 million and 500 million years ago. They also speculate that it may have contributed in some way to the separation of Australia from the Antarctic landmass, which were both part of a supercontinent called Gondwana. Levels of iridium and quartz fracturing in the Permian-Triassic layer do not approach those of the Cretaceous-Tertiary boundary layer. Given that a far greater proportion of species and individual organisms became extinct during the former, doubt is cast on the significance of a meteor impact in creating the latter. Further doubt has been cast on this theory based on fossils in Greenland showing the extinction to have been gradual, lasting about eighty thousand years, with three distinct phases.

Many scientists believe that the Permian-Triassic extinction event was caused by a combination of some or all of the hypotheses above and other factors; the formation of Pangaea decreased the number of coastal habitats and may have contributed to the extinction of many clades.

See also

Notes

  1. ^ The term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian system" after the ancient kingdom of Permia, and not after the then small town of Perm, as usually assumed; see "Origin of the Permian"

References

  1. ^ Image:Sauerstoffgehalt-1000mj.svg
  2. ^ Image:Phanerozoic Carbon Dioxide.png
  3. ^ Image:All palaeotemps.png
  4. ^ Haq, B. U. (2008). "A Chronology of Paleozoic Sea-Level Changes". Science 322: 64–68. doi:10.1126/science.1161648. 
  5. ^ Gradstein, Felix M.; Ogg, J. G.; Smith, A. G. (2004). A Geologic Time Scale 2004. Cambridge: Cambridge University Press. ISBN 0521786738. 
  6. ^ "Late Permian" GeoWhen Database, International Commission on Stratigraphy (ICS)
  7. ^ "Middle Permian" GeoWhen Database, International Commission on Stratigraphy (ICS)
  8. ^ "Kazanian"] GeoWhen Database, International Commission on Stratigraphy (ICS)
  9. ^ "Early Permian" GeoWhen Database, International Commission on Stratigraphy (ICS)
  10. ^ a b c d http://www.palaeos.com/Paleozoic/Permian/Permian.htm
  11. ^ Xu, R. & Wang, X.-Q. (1982): Di zhi shi qi Zhongguo ge zhu yao Diqu zhi wu jing guan (Reconstructions of Landscapes in Principal Regions of China). Ke xue chu ban she, Beijing. 55 pages, 25 plates.
  12. ^ Zimmerman EC (1948) Insects of Hawaii, Vol. II. Univ. Hawaii Press
  13. ^ Grzimek HC Bernhard (1975) Grzimek's Animal Life Encyclopedia Vol 22 Insects. Van Nostrand Reinhold Co. NY.
  14. ^ Riek EF Kukalova-Peck J (1984) A new interpretation of dragonfly wing venation based on early Upper Carboniferous fossils from Argentina (Insecta: Odonatoida and basic character states in Pterygote wings.) Can. J. Zool. 62; 1150-1160.
  15. ^ Wakeling JM Ellington CP (1997) Dragonfly flight III lift and power requirements. Journal of Experimental Biology 200; 583-600, on p589
  16. ^ Matsuda R (1970) Morphology and evolution of the insect thorax. Mem. Ent. Soc. Can. 76; 1-431.
  17. ^ Riek EF Kukalova-Peck J (1984) A new interpretation of dragonfly wing venation based on early Upper Carboniferous fossils from Argentina (Insecta: Odonatoida and basic character states in Pterygote wings.) Can. J. Zool. 62; 1150-1160
  18. ^ http://geology.about.com/od/extinction/a/aa_permotrias.htm
  19. ^ http://www.kgs.ku.edu/Extension/fossils/massExtinct.html
  20. ^ http://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event
  21. ^ http://www.historyfiles.co.uk/FeaturesPrehistory/Permian_Extinction01.htm
  22. ^ Sahney, S. and Benton, M.J. (2008). "Recovery from the most profound mass extinction of all time" (PDF). Proceedings of the Royal Society: Biological 275: 759. doi:10.1098/rspb.2007.1370. http://journals.royalsociety.org/content/qq5un1810k7605h5/fulltext.pdf. 
  • Ogg, Jim; June, 2004, Overview of Global Boundary Stratotype Sections and Points (GSSP's) http://www.stratigraphy.org/gssp.htm Accessed April 30, 2006.
  • Kump, L.R., A. Pavlov, and M.A. Arthur (2005). "Massive release of hydrogen sulfide to the surface ocean and atmosphere during intervals of oceanic anoxia". Geology 33 (May): 397–400. doi:10.1130/G21295.1. 

External links

Preceded by Proterozoic Eon 542 Ma - Phanerozoic Eon - Present
542 Ma - Paleozoic Era - 251 Ma 251 Ma - Mesozoic Era - 65 Ma 65 Ma - Cenozoic Era - Present
Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Paleogene Neogene Quaternary

1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

PERMIAN, in geology, the youngest and uppermost system of strata of the Palaeozoic series, situated above the Carboniferous and below the Trias. The term " Permian " (derived from the ri.

Russian province of Perm, where the rocks are extensively developed) was introduced in 1841 by Sir R. I. Murchison. In England the series of red sandstones, conglomerates, breccias and marls which overlie the Coal Measures were at one time grouped together in one great formation as the " New Red Sandstone," in contradistinction to the Old Red Sandstone below the Carboniferous: they were likewise known as the Poikilitic series (from Gr. 7roLKLAos, mottled) from their mottled or variegated colour. They are now divided into two systems or groups of formations; the lower portion being included in the Palaeozoic series under the name Permian, the upper portion being relegated to the Mesozoic series and termed Trias. In Germany the name Dyas was proposed by J. Marcou for the rocks of this age on account of the twofold nature of the series in Thuringia, Saxony, &c. The intimate stratigraphical relationship that exists in many quarters between the Permian rocks and the Carboniferous beds, and the practical difficulties in the way of drawing a satisfactory base-line to the system, have led to the adoption of the term Permo-carboniferous in South Africa, southern Asia, America, Australia and Russia, for strata upon this horizon: C. W. von Giimbel used " Post-carbon " in this sense. In a similar manner Permo-triassic has been employed in cases where a stratigraphical passage from rocks with Permian fossils to others bearing a Triassic fauna is apparent.

The Permian system in England consists of the following subdivisions W. of England. E. of England.

Red sandstones, clays, and gypsum Magnesian limestone Marl slate I Red and variegated sandstone Reddish-brown and purple sandstones and marls, with calcareous conglomerates and breccias of volcanic rocks From the thicknesses here given it is evident that the Permian rocks have a very different development on the two sides of England. On the east side, from the coast of Northumberland southwards to the plains of the Trent, they consist chiefly of a great central mass of limestone. But on the west side of the Pennine Chain, and extending southwards into the central counties, the calcareous zone disappears, and we have a great accumulation of red, arenaceous and gravelly rocks.

The lower subdivision attains its greatest development in the vale of the Eden, where it consists of brick-red sandstones, the Penrith sandstone series, with some beds of calcareous conglomerate or breccia, locally known as " brockram," derived from the waste of the Carboniferous Limestone. These red rocks extend across the Solway into the valleys of the Nith and Annan, in the south of Scotland, where they lie unconformably on the Lower Silurian rocks. Their breccias consist of fragments of the adjacent Silurian greywackes and shales, but near Dumfries some calcareous breccias or ' ` brockrams " occur. These brecciated masses have evidently accumulated in small lakes or narrow fiords. Much farther south, in Staffordshire, and in the districts of the Clent and Abberley Hills, the brecciated conglomerates in the Permian series attain a thickness of 400 ft. They have been shown by Sir A. C. Ramsay to consist in large measure of volcanic rocks, grits, slates and limestones, which can be identified with rocks on the borders of Wales. Some of the stones are 3 ft. in diameter and show distinct striation. The same writer pointed out that these Permian drift-beds cannot be distinguished by any essential character from modern glacial drifts; on the other hand, W. W. King and others have opposed this view. The middle subdivision is the chief repository of fossils in the Permian system. Its strata are not red, but consist of a lower zone of hard brown shale with occasional thin limestone bands (Marl Slate) and an upper thick mass of dolomite (Magnesian Limestone). The latter is the chief feature in the Permian development of the east of England. It corresponds with the Zechstein of Germany, as the Marl Slate does with the Kupfer-schiefer. It is a very variable rock in its lithological characters, being sometimes dull, earthy, fine-grained and fossiliferous, in other places quite crystalline, and composed of globular, reniform, botryoidal, or other irregular concretions of crystalline and frequently internally radiated dolomite. Though the Magnesian Limestone runs as a thick persistent zone down the east of England, it is represented on the Lancashire and Cheshire side by bright red and variegated sandstone covered by a thin group of red marls, with numerous thin courses of limestone, containing Schizodus, Bakevellia and other characteristic fossils of the Magnesian Limestone.

Concerning the rocks classed as Permian in the central counties of England there exists some doubt, for recent work tends to show that the lower parts are clearly related to the Carboniferous rocks by their fossils; while there is little evidence to warrant the exclusion of the higher beds from the Trias. Similarly in south Devon, where red sandstones and coarse breccias are well exposed, it has been found difficult to say whether the series should be regarded as Triassic or Permian, though the prevailing tendency is to retain them in the latter system.

The " Dyas " type of the system is found in enormous masses of strata flanking the Harz Mountains, and also in the Rhine provinces, Saxony, Thuringia, Bavaria and Bohemia. In general terms it may be said that in this region there is a lower sandy and conglomeratic subdivision with an upper one more calcareous; the former is known as the Rothliegende, the latter as the Zechstein group. On the south side of the Harz Mountains the following subdivisions are recognized Anhydrite, gypsum, rock-salt, dolomite, marl, fetid shale and limestone. The amorphous gypsum is the chief member of this group; the limestone is sometimes full of bitumen.

Dolomite (Haupt-dolomit), crystalline granular Middle (Rauchwacke), and fine powdery (Asche) with gypsum at bottom.

r Zechstein-limestone, an argillaceous, thin-bedded 1 compact limestone 15 to 90 ft. thick.

Lower ..j Kupfer-schiefer, a black bituminous copper-bearing shale, not more than 2 ft. thick, often much less, but very constant.

Zechstein-conglomerate and calcareous sandstone.

Red sandstones (Kreuznach beds), red shales Upper' (Monsig beds) with sheets of melaphyre tuff, and quartz-porphyry-conglomerate (Wadern, Oberhof, Sotern and Tambach beds).

Sandstones and glomerates (Tholayer beds) on black shales with poor coal seams and clay ironstones (Lebach and Goldlauter beds).

Lower Sandstones and shales with seams of coal on red and grey sandstones and shales with impure limestones (Cusel beds, including Manebach beds, upper, and Gehren beds, lower).

Missing image
Permian-1.jpg

The name Rothliegende or Rothtodtliegende (red-dead-layer) was given by the miners because their ores disappeared in the red rocks below the copper-bearing Kupfer-schiefer. The Kupferschiefer, although so thin, has been worked in the Mansfeld district for a long period; it contains abundant remains of fish (Palaeoniscus, Platysomus) and plants (Ullmannia). The beds of rock-salt in the German Zechstein are of the greatest importance; at Sperenberg near Berlin it has been penetrated to a depth of 4000 ft. Associated with the salt, gypsum and anhydrite are numerous Permian Period ci 0 ?

a, N ?

0 3. Upper ...

2. Middle .

1. Lower ...

600 ft. 50-100 ft.

10-30 " 600 " 3000 " 100-250 " Upper potassium and magnesium salts, including carnallite, kieserite and polyhalite, which are exploited at Stassfurt and are the only important potassium deposits known. Permian rocks of the Rothliegende type are scattered over a wide area in France, where the lower beds are usually conformable with the Coal Measures. In the upper beds occur the bituminous or " Boghead " shale of Autun. In Russia strata of this age cover an enormous area, in the Ural region, in the governments of Perm, Kasan, Kostroma, and in Armenia. The Russian Permian shows no sharp division into two series; the two types of deposit tend to be more mixed and include in addition some deposits of the more open sea. The general sequence begins with the Artinsk beds, sandy and marly or conglomeratic beds in close connexion with the Carboniferous, overlain by the Kurigur limestones and dolomites; these are followed by red fresh-water sandstones, over which comes an important series of copper-bearing sandstones and conglomerates. Above this, in Kostroma, Vyatka and Kasan there is a calcareous and dolomitic series, the so-called " Russian Zechstein " with marine fossils; the uppermost beds are red marls, with few fresh-water fossils, the Tartarian beds.

The character of the fossils in the Permian of the Mediterranean and south-east Europe - well exemplified in the deposits of Sicily - together with their more generally calcareous nature, indicate a more open sea and more stable marine conditions than obtained farther north. This sea is traceable across south-east Russia into the middle of Asia, through Turkestan and Persia, into the Salt Range of India, where the Productus limestone may be taken as representative of the normal marine plan of Permian times. Southwards, however, of the Nerbudda River another and quite distinct continental assemblage of deposits holds the ground, viz. the lower portion of the great fresh-water Gondwana system. The coarse Talchir conglomerates at the base are succeeded by the sandstones and shales of the Karharbari group, with numerous coal seams, and these in turn are followed by the Damuda series (upwards of Io,000 ft.) of similar rocks, with ironstones and very valuable coal seams. All these strata are characterized by the presence of the Glossopteris flora. A similar succession of beds has been recorded in north-west Afghanistan. In close relationship with the lower members of the Indian Gondwana series, both as regards fossil contents and lithological characters, are the lower Karoo beds of South Africa (Dwyka conglomerate, Ecca shales and mudstones, Beaufort beds and Kimberley shales), also the coalbearing beds of the Transvaal; the Permo-carboniferous rocks of Australia (including the rich coal measures of Newcastle, the Greta coal measures and marine beds, upper and lower, of New South Wales; those of Tasmania, the Bowen River beds of Queensland, and the Bacchus Marsh glacial beds of Victoria), and similar rocks in New Zealand (Maitai formation, south island; Dun Mountain limestone and Rimutaka beds of the north island) and South America. In North America Permian rocks occur in the east in Pennsylvania, West Virginia, Maryland and Ohio (" Upper Barren Measures "), and in Prince Edward Island, New Brunswick, where they succeed the Carboniferous rocks very regularly. West of the Mississippi, in Texas (7000 ft., including the Wichita beds, Clear Fork and Double Mountain beds), Kansas and Nebraska, the Permian is more extensive and on the whole is more readily separable from the Carboniferous. Here the lower beds are marine and contain many limestones and dolomites; the higher beds are mainly red sand stones and marls with gypsum; in Texas it is of interest to note the occurrence of copper-stained strata. These upper " Red Beds " are often not clearly distinguishable from the Trias.

Life of the Permian Period

The records of the plants and animals of this period are comparatively meagre. The plants show that a gradual change from the Carboniferous types was in progress. Two floral regions are clearly indicated, a northern and a southern. In the latter, which may be regarded as conterminous with the continent of Gondwana, the Lepidodendrons, Sigillarias, Calamites, &c., of the Coal Measures gave place to a distinct flora, named from the prevalence of Glossopteris, the Glossopteris (tongue-fern) flora. Traces of this southern flora have been found in northern Russia. Gangamopteris, Callipteris, Taeniopteris, Schizopteris, Walchia, Voltzia, Ullmannia, Saportea, Baiera are characteristic Permian genera. Among the larger animals amphibians occupied a prominent position, their footprints being very common in the sandstones; they include numerous Labyrinthodonts, Archegosaurus, Stereorachis, Branchiosaurus. At this time the true reptiles began to leave their remains in the rocks; many highly interesting forms are known - Palaeohatteria, Proterosaurus, Stereosternum; others having certain mammalian characteristics include Pareiosaurus, Cynognathus, Dicynodon. Among the fishes may be mentioned Platysomus, Palaeoniscus, Amblypterus, Pleuracanthus. Turning to the invertebrates, undoubtedly the most interesting feature is gradual introduction into the Cephalopoda of the ammonite-like forms such as Medlicottia, Waagenoceras, Popanoceras, +n place of the more simple lobed goniatites of the Carboniferous. Brachiopods (Productus horridus, Bakevellia tumida), Bryozoa and corals were by no means scarce in the more open Permian seas. Schizodus Schlotheimii, Strophalosia Goldfussi, Myophoria, Leimyalind, Bellerophon are characteristic Permian molluscs. The last of the trilobites appears in the Permian of North America.

The evidence so far obtained indicates that in Permian times much of the land in the northern hemisphere was near the general sea-level, and that conditions of considerable aridity prevailed which involved the repeated isolation and evaporation of marine lagoons and land-locked seas. South of this region in Europe and Asia there extended an open " Mediterranean " sea, the " Tethys " of E. Suess; while over an enormous area in the southern hemisphere a great land area was spread, " Gondwana land," the land of the Glossopteris flora. At many points in this vast tract, as we have seen, coarse conglomeratic deposits, Talchir, Dwyka, Bacchus Marsh, &c., indicate profound glacial conditions, which some have thought were present also in Britain, Germany and elsewhere in the north. Moderate earth movements were taking place in North America, where the Appalachian and Ouachita mountains were in course of elevation, and in Europe this was a time of great volcanic activity. In the Saal region volcanic rocks in the lower Rothliegende have been penetrated for 1100 ft. without reaching the bottom, and elsewhere in central Europe great sheets of contemporaneous quartz porphyry, granite porphyry, melaphyre and porphyrite are abundant with their corresponding tuffs. Melaphyres and tuffs appear in the Vosges, which in the south of France are enormous masses of melaphyre and quartz porphyry. Basic lavas and tuffs - diabase, pierite, olivine basalt and andesite tuffs - were erupted from many small vents in Ayrshire and the Nith basin, and basic lavas occur also in Devonshire. Volcanic rocks occur also in New Zealand, Sumatra and the Transvaal.

Table of Permian Strata, showing approximate correlations.

Stages.

Britain.

Saxony,

Thuringia,

Bohemia.

Basin of the

Saar.

Alps.

Russia.

India.

North America.

Bellerophon

Tartarian

:~

c

-

Thuringian

g

Marls and

gypsum.

Magnesian

g

limestone.

Salt beds of

Stassfurt.

Zechstein lime-

stones.

F,

t

-a

,.

Upper red

pp

sandstones

breccias and

limestone.

Dolomites

and shales

of Neumarkt.

Marls.

Cephalopod

beds of

Armenia.

a Q a

° C

cs u

-a E

a

(2

-.

a

?

°

a V

,,

a

Kansas. ° i^ .?

Marl slate.

Kupfer-schiefer.

N

conglomerates

g

Sandstones

Copper-

o ?,

i

Kiger

of Groden.

bearing

sandstones

in Ural

region.

g

Limestones

and dolo-

Q g

- -a u

a a °.-

2 t a ' U

4. a 6 ,, -

..

.,

°

Q c!?

°' c.

6 t a

v

-?

stage. °

Salt Fork 3 x

stage. ° - ° 3

Q a c

c

w

° G5

Punjabian

--

??

c,.,? a

m 4.

a 2

x

o

Weissliegendes.

g

Tambach beds.

Oberhof beds.

4.1)

a

bo

Red sands tones

with eruptive

rocks.

The beds of

o

'a '

°

u

or

Saxonian

o °

-6 cn

° o

c

a .x

o ti a

a y

ti

a' °.2. E

cv

a

a

.

a

,?

o

y

Goldlauter

beds.

;

"

Kreuznach,

Wadern,

SStern,

Tholey.

>

a

II

d

mites of

Kostroma

(Russian

Zechstein).

Kungur and

Artinsk

sandston es.

Beds of

Novaya

Zembl a and

y

' o bA °

.o o? &

s °

? a

x cn

po ow E

?; +, a

°, a

°'

a °

.[ g b ' 0

a

it

? '

a -,

`-3

c? U

,? .

d

3

° u

3 u4

., w

° d

?

,

?=

6

a 3

- a cd

? ?' `~

Wellin ton U °

g 6 cn

be d s.

Marion

beds.

Chase;? -o

Artinskian

(marine)

Autunian

an

M anebach

eds.

Brandschiefer

beds of Wessig.

Gehren beds.

°'

a

° b0

Leb ach be ds.

C usel beds.

o

1.

(continental)

rx ?, > >

v

_'

2

o

U

Braunau beds

of Bohemia.

?'

o

>

Spitzbergen.

°'

M1 1,-

H --a

stage. .n ?,,

l

REFERENCES. - The literature dealing with the Permian and Permo-Carboniferous is very extensive; H. B. Geinitz, J. Marcou, Sir R. I. Murchison, Sir A. C. Ramsay, H. Potonie, R. Zeiller, O. Feistmantel, E. A. Newell, Arber, A. C. Seward, F. Bischoff, C. Ochsensius, E. Mojsisovics, V. Amalitzky, F. Noetling, C. Diener, A. Tschneryschew, A. Karpinsky, W. Waagen, H. F. and W. T. Blanford, G. H. Girty and very many others have made important contributions to the subject. Numerous references will be found in Sir A. Geikie, Textbook of Geology, 4th ed., and in the annual Geological Literature of the Geological Society of London. See also an interesting summary by C. Schuchert, " The Russian Carboniferous and Permian compared with those of India and America," Amer. Journ. Sci. (1906), 4th series, vol. xxii. pp. 29 seq. and a general account of the system in Lethaea geognostica, Th. I. Bd. II., F. Frech and others (Stuttgart 1897-1902). H. Everding, " Zur Geologie der deutschen Zechsteinsalze," Kgl. geolog. Landesanst. (Berlin, 1907) gives a full account of the salt and potassium-bearing beds. (J. A. H.)


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Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

Contents

English

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Wikipedia

Adjective

Permian (comparative more Permian, superlative most Permian)

Positive
Permian

Comparative
more Permian

Superlative
most Permian

  1. (geology) Of a geologic period within the Paleozoic era; comprises the Cisuralian, Guadalupian and Lopingian epochs from about 280 to 248 million years ago.

Proper noun

Singular
Permian

Plural
-

Permian

  1. (geology) The Permian period.

See also


Simple English

The Permian is a geological period which started 299 million years ago, and ends 251 million years ago. It is the last period of the Paleozoic era, and ended in the largest mass extinction known to science.

During the Permian tetrapod life, (amphibians, Sauropsids and Synapsids) which evolved in the Carboniferous, became widespread and diverse. The first modern trees (conifers, ginkgos and cycads) appeared in the Permian.[1]

The Permian was also a period of adaptive radiation in insects. Beetles appeared; 22 out of a total of 36 known orders are known from the Permian. Some became extinct in the end-Permian event, but more radiation followed in the Mesozoic. Insects were probably, by the end of the Permian, the largest phylum[2] in terms of number of species.[3]

All the major land masses were collected together in the super-continent Pangea. At the end of the period, the greatest flood basalt lava flows in the Phanerozoic raised world temperatures, and damaged the environment. These formed the extensive Siberian traps. The causes of the Permian/Triassic extinction event are not yet agreed between scientists.[4] Trilobites, once a dominant life-form in the ocean, became extinct, together with 90% of all marine species.

References

  1. Levin, Harold L. 2005. The Earth through time. 8th ed, Wiley, N.Y. Chapter 4: The fossil record.
  2. or class, depending on how they are classified.
  3. Wooton R.J. 1990. Major insect radiations. In P.D. Taylor & G.P. Larwood eds. Major evolutionary radiations. Oxford.
  4. Erwin D.H. 1993. The great Palaeozoic crisis: life & death in the Permian. Columbia, N.Y.








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