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The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years, from the end of the Carboniferous Period Ma (million years ago) to the beginning of the Triassic Period 251.902 Ma. It is the sixth and last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the Perm Governorate in Russia. (2025). 9780444637710, Elsevier. ISBN 9780444637710
The Permian witnessed the diversification of the two groups of , the and the Sauropsida (). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors.
Various authors recognise at least three, and possibly four extinction events in the Permian. The end of the Early Permian (Cisuralian) saw a major faunal turnover, with most lineages of primitive "pelycosaur" synapsids becoming extinct, being replaced by more advanced therapsids. The end of the Capitanian Stage of the Permian was marked by the major Capitanian mass extinction event, associated with the eruption of the Emeishan Traps. The Permian (along with the Paleozoic) ended with the Permian–Triassic extinction event (colloquially known as the Great Dying), the largest mass extinction in Earth's history (which is the last of the three or four crises that occurred in the Permian), in which nearly 81% of marine species and 70% of terrestrial species died out, associated with the eruption of the Siberian Traps. It took well into the Triassic for life to recover from this catastrophe; on land, ecosystems took 30 million years to recover.
The term Permian was introduced into geology in 1841 by Sir Roderick Impey Murchison, president of the Geological Society of London, after extensive Russian explorations undertaken with Édouard de Verneuil in the vicinity of the Ural Mountains in the years 1840 and 1841. Murchison identified "vast series of beds of marl, schist, limestone, sandstone and conglomerate" that succeeded Carboniferous strata in the region.Benton, M.J. et al., Murchison's first sighting of the Permian, at Vyazniki in 1841 , Proceedings of the Geologists' Association, accessed 2012-02-21Murchison, Roderick Impey (1841) "First sketch of some of the principal results of a second geological survey of Russia", Philosophical Magazine and Journal of Science, series 3, 19 : 417–422. From p. 419: "The carboniferous system is surmounted, to the east of the Volga, by a vast series of marls, schists, limestones, sandstones and conglomerates, to which I propose to give the name of "Permian System," … ." Murchison, in collaboration with Russian geologists, named the period after the surrounding Russian region of Perm, which takes its name from the medieval kingdom of Great Perm that occupied the same area hundreds of years prior, and which is now located in the Perm Krai administrative region. Between 1853 and 1867, Jules Marcou recognised Permian strata in a large area of North America from the Mississippi River to the Colorado River and proposed the name Dyassic, from Dyas and Trias, though Murchison rejected this in 1871. The Permian system was controversial for over a century after its original naming, with the United States Geological Survey until 1941 considering the Permian a subsystem of the Carboniferous equivalent to the Mississippian and Pennsylvanian.
| Early Triassic | Induan | 251.902 ±0.024 |
| Lopingian | Changhsingian | 254.14 ±0.07 |
| Wuchiapingian | 259.51 ±0.21 | |
| Guadalupian | Capitanian | 264.28 ±0.16 |
| Wordian | 266.9 ±0.4 | |
| Roadian | 273.01 ±0.14 | |
| Cisuralian | Kungurian | 283.5 ±0.6 |
| Artinskian | 290.1 ±0.26 | |
| Sakmarian | 293.52 ±0.17 | |
| Asselian | 298.9 ±0.15 |
Historically, most marine biostratigraphy of the Permian was based on Ammonoidea; however, ammonoid localities are rare in Permian stratigraphic sections, and species characterise relatively long periods of time. All GSSPs for the Permian are based around the first appearance datum of specific species of conodont, an enigmatic group of jawless with hard tooth-like oral elements. Conodonts are used as Biostratigraphy for most of the Palaeozoic and the Triassic.
The Asselian was named by the Russian stratigrapher V.E. Ruzhenchev in 1954, after the Assel River in the southern Ural Mountains. The GSSP for the base of the Asselian is located in the Aidaralash River valley near Aqtöbe, Kazakhstan, which was ratified in 1996. The beginning of the stage is defined by the first appearance of Streptognathodus.Davydov, V.I., Glenister, B.F., Spinosa, C., Ritter, S.M., Chernykh, V.V., Wardlaw, B.R. & Snyder, W.S. 1998. Proposal of Aidaralash as Global Stratotype Section and Point (GSSP) for base of the Permian System . Episodes, 21, 11–17.
The Sakmarian is named in reference to the Sakmara River in the southern Urals, and was coined by Alexander Karpinsky in 1874. The GSSP for the base of the Sakmarian is located at the Usolka section in the southern Urals, which was ratified in 2018. The GSSP is defined by the first appearance of Sweetognathus.
The Artinskian was named after the city of Arti in Sverdlovsk Oblast, Russia. It was named by Karpinsky in 1874. The Artinskian currently lacks a defined GSSP. The proposed definition for the base of the Artinskian is the first appearance of Sweetognathus aff. S. whitei.
The Kungurian takes its name after Kungur, a city in Perm Krai. The stage was introduced by Alexandr Antonovich Stukenberg in 1890. The Kungurian currently lacks a defined GSSP. Recent proposals have suggested the appearance of Neostreptognathodus pnevi as the lower boundary.
The Roadian was named in 1968 in reference to the Road Canyon Member of the Word Formation in Texas. The GSSP for the base of the Roadian is located 42.7m above the base of the Cutoff Formation in Stratotype Canyon, Guadalupe Mountains, Texas, and was ratified in 2001. The beginning of the stage is defined by the first appearance of Jinogondolella.
The Wordian was named in reference to the Word Formation by Johan August Udden in 1916, Glenister and Furnish in 1961 was the first publication to use it as a chronostratigraphic term as a substage of the Guadalupian Stage. The GSSP for the base of the Wordian is located in Guadalupe Pass, Texas, within the sediments of the Getaway Limestone Member of the Cherry Canyon Formation, which was ratified in 2001. The base of the Wordian is defined by the first appearance of the conodont Jinogondolella aserrata.
The Capitanian is named after the Capitan Reef in the Guadalupe Mountains of Texas, named by George Burr Richardson in 1904, and first used in a chronostratigraphic sense by Glenister and Furnish in 1961 as a substage of the Guadalupian Stage. The Capitanian was ratified as an international stage by the ICS in 2001. The GSSP for the base of the Capitanian is located at Nipple Hill in the southeast Guadalupe Mountains of Texas, and was ratified in 2001, the beginning of the stage is defined by the first appearance of Jinogondolella postserrata.
The Wuchiapinginan and Changhsingian were first introduced in 1962, by J. Z. Sheng as the "Wuchiaping Formation" and "Changhsing Formation" within the Lopingian series. The GSSP for the base of the Wuchiapingian is located at Penglaitan, Guangxi, China and was ratified in 2004. The boundary is defined by the first appearance of Clarkina The Changhsingian was originally derived from the Changxing Limestone, a geological unit first named by the Grabau in 1923, ultimately deriving from Changxing County, Zhejiang .The GSSP for the base of the Changhsingian is located 88 cm above the base of the Changxing Limestone in the Meishan D section, Zhejiang, China and was ratified in 2005, the boundary is defined by the first appearance of Clarkina wangi.
The GSSP for the base of the Triassic is located at the base of Bed 27c at the Meishan D section, and was ratified in 2001. The GSSP is defined by the first appearance of the conodont Hindeodus.
In North America, the Permian is divided into the Wolfcampian (which includes the Nealian and the Lenoxian stages); the Leonardian (Hessian and Cathedralian stages); the Guadalupian; and the Ochoan, corresponding to the Lopingian. (1995). 9783642785955 ISBN 9783642785955
The New Zealand geologic time scale divides the Permian into three epochs, Pre-Telfordian (undivided), D'Urville (divided into the Makarewan, Waiitian, and Puruhauan stages), and Aparima (Flettian, Barrettian, Mangapirian, and Telfordian stages). The Pre-Telfordian epoch corresponds approximately to the Asselian, Sakmarian, and Artinskian stages; the D'Urville epoch is roughly contemporary with the Kungurian stage and Guadalupian epoch; and the Aparima epoch is closely contemporary with the Lopingian epoch.
Large continental landmass interiors experience climates with extreme variations of heat and cold ("continental climate") and monsoon conditions with highly seasonal rainfall patterns. seem to have been widespread on Pangaea. (1995). 9783642785955 ISBN 9783642785955 Such dry conditions favored , plants with seeds enclosed in a protective cover, over plants such as that disperse in a wetter environment. The first modern trees (Pinophyta, and ) 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, including the Texas red beds. The Permian Basin in the U.S. states of Texas and New Mexico is so named because it has one of the thickest deposits of Permian rocks in the world.
In the late Kungurian, cooling resumed, resulting in a cool glacial interval that lasted into the early Capitanian, though average temperatures were still much higher than during the beginning of the Cisuralian. Another cool period began around the middle Capitanian. This cool period, lasting for 3–4 Myr, was known as the Kamura Event. It was interrupted by the Emeishan Thermal Excursion in the late part of the Capitanian, around 260 million years ago, corresponding to the eruption of the Emeishan Traps. Alt URL This interval of rapid climate change was responsible for the Capitanian mass extinction event.
During the early Wuchiapingian, following the emplacement of the Emeishan Traps, global temperatures declined as carbon dioxide was weathered out of the atmosphere by the large igneous province's emplaced basalts. The late Wuchiapingian saw the finale of the Late Palaeozoic Ice Age, when the last Australian glaciers melted. The end of the Permian is marked by a temperature excursion, much larger than the Emeishan Thermal Excursion, at the Permian-Triassic boundary, corresponding to the eruption of the Siberian Traps, which released more than 5 teratonnes of CO2, more than doubling the atmospheric carbon dioxide concentration. Alt URL A -2% δ18O excursion signifies the extreme magnitude of this climatic shift. This extremely rapid interval of greenhouse gas release caused the Permian-Triassic mass extinction, as well as ushering in an extreme hothouse that persisted for several million years into the next geologic epoch, the Triassic.
The Permian climate was also extremely seasonal and characterised by megamonsoons, which produced high aridity and extreme seasonality in Pangaea's interiors. Precipitation along the western margins of the Palaeo-Tethys Ocean was very high. Evidence for the megamonsoon includes the presence of megamonsoonal rainforests in the Qiangtang Basin of Tibet, enormous seasonal variation in sedimentation, bioturbation, and ichnofossil deposition recorded in sedimentary facies in the Sydney Basin, and palaeoclimatic models of the Earth's climate based on the behaviour of modern weather patterns showing that such a megamonsoon would occur given the continental arrangement of the Permian. The aforementioned increasing equatorial aridity was likely driven by the development and intensification of this Pangaean megamonsoon.
The Permian began with the Carboniferous flora still flourishing. About the middle of the Permian a major transition in vegetation began. The swamp-loving Lycopodiophyta trees of the Carboniferous, such as Lepidodendron and Sigillaria, were progressively replaced in the continental interior by the more advanced seed ferns and early Pinophyta as a result of the Carboniferous rainforest collapse. At the close of the Permian, lycopod and Equisetopsida swamps reminiscent of Carboniferous flora survived only in Cathaysia, a series of equatorial islands in the Paleo-Tethys Ocean that later would become South China.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.
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 Ginkgoopsida and also appeared during this period.
The Middle Permian faunas of South Africa and Russia are dominated by therapsids, most abundantly by the diverse Dinocephalia. Dinocephalians become extinct at the end of the Middle Permian, during the Capitanian mass extinction event. Late Permian faunas are dominated by advanced therapsids such as the predatory sabertoothed and herbivorous beaked , alongside large herbivorous pareiasaur Parareptilia. The Archosauromorpha, the group of reptiles that would give rise to the , , and in the following Triassic, first appeared and diversified during the Late Permian, including the first appearance of the Archosauriformes during the latest Permian. , the group of therapsids ancestral to modern , first appeared and gained a worldwide distribution during the Late Permian. Another group of therapsids, the (such as Lycosuchus), arose in the Middle Permian. There were no flying vertebrates, though the extinct lizard-like reptile family Weigeltisauridae from the Late Permian had extendable wings like modern gliding lizards, and are the oldest known gliding vertebrates.
Temnospondyls reached a peak of diversity in the Cisuralian, with a substantial decline during the Guadalupian-Lopingian following Olson's extinction, with the family diversity dropping below Carboniferous levels.
Embolomeri, a group of aquatic crocodile-like limbed vertebrates that are Reptiliomorpha under some phylogenies. They previously had their last records in the Cisuralian, are now known to have persisted into the Lopingian in China.
Modern amphibians () are suggested to have originated during Permian, descending from a lineage of Dissorophoidea temnospondyls or Lepospondyli.
The oldest likely record of Ginkgoales (the group containing Ginkgo and its close relatives) is Trichopitys heteromorpha from the earliest Permian of France. The oldest known fossils definitively assignable to modern are known from the Late Permian. In Cathaysia, where a wet tropical frost-free climate prevailed, the Noeggerathiales, an extinct group of tree fern-like were a common component of the flora The earliest Permian (~ 298 million years ago) Cathyasian Wuda Tuff flora, representing a coal swamp community, has an upper canopy consisting of lycopsid tree Sigillaria, with a lower canopy consisting of Marattiaceae tree ferns, and Noeggerathiales. Early appeared in the Late Carboniferous, represented by primitive conifers, but were replaced with more derived Voltziales during the Permian. Permian conifers were very similar morphologically to their modern counterparts, and were adapted to stressed dry or seasonally dry climatic conditions. The increasing aridity, especially at low latitudes, facilitated the spread of conifers and their increasing prevalence throughout terrestrial ecosystems. Bennettitales, which would go on to become in widespread the Mesozoic, first appeared during the Cisuralian in China. Lyginopteridales, which had declined in the late Pennsylvanian and subsequently have a patchy fossil record, survived into the Late Permian in Cathaysia and equatorial east Gondwana.
There is evidence that magma, in the form of flood basalt, poured onto the Earth's surface in what is now called the Siberian Traps, for thousands of years, contributing to the environmental stress that led 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 the release of enough carbon dioxide from the eruptions to raise world temperatures five degrees Celsius. Palaeos: Life Through Deep Time > The Permian Period Accessed 1 April 2013.
Another hypothesis involves ocean venting of hydrogen sulfide gas. Portions of the Deep sea will periodically lose all of its dissolved oxygen allowing bacteria that live without oxygen to flourish and produce hydrogen sulfide gas. If enough hydrogen sulfide accumulates in an Anoxic event, 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. Hydrogen sulfide levels might have increased dramatically over a few hundred years. Models of such an event indicate that the gas would destroy ozone in the upper atmosphere allowing ultraviolet radiation to kill off species that had survived the toxic gas. There are species that can metabolize hydrogen sulfide.
Another hypothesis builds on the flood basalt eruption theory. An increase in temperature of five degrees Celsius would not be enough 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 melted, expelling enough methane (among the most potent ) into the atmosphere to raise world temperatures an additional five degrees Celsius. The frozen methane hypothesis helps explain the increase in carbon-12 levels found midway in 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.
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