Permian period 299 - 251 million years ago ↓ PЄ Є O S D C P T J K PG N
Mean atmospheric O2 content over period duration	ca. The Precambrian ( Pre-Cambrian) is an informal name for the supereon comprising the eons of the Geologic timescale that came before the current The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with The Ordovician is a geologic period and system, the second of six of the Paleozoic era, and covers the time between 488 The Silurian is a geologic period and system that extends from the end of the Ordovician period about 443 The Devonian is a geologic period and system of the Paleozoic era spanning from to  million years ago. The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359 The Triassic is a geologic period and system that extends from about 251 to 199 Ma (million years ago The Jurassic is a geologic period and system that extends from about Ma (million years ago to  Ma that is from the end of the Triassic to the beginning The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of The Paleogene (alternatively Palaeogene) is a geologic period and system that began 65 The Neogene is a geologic period and system starting 2303 ± 0 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the 23 Vol %[1] (115 % of modern level)
Mean atmospheric CO2 content over period duration	ca. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single 900 ppm[2] (3 times pre-industrial level)
Mean surface temperature over period duration	ca. "Parts-per" notation is used especially in Science and Engineering, to denote Ratios (relative proportions in measured quantities particularly 16°C [3] (2°C above modern level)
Key events in the Permian view • discuss • edit -300 — – -295 — – -290 — – -285 — – -280 — – -275 — – -270 — – -265 — – -260 — – -255 — – -250 —       Penn- sylvanian   Asselian Sakmarian Artinskian Kungurian Roadian Wordian Captainian Wuchia- pingian Changhsin…   Triassic   ← Mass extinction P e r m i a n  Mesozoic  Palæozoic  Lopingian (Upper Permian)  Guadalupian (Middle Permian)  Cisuralian (Lower Permian) An approximate timescale of key Permian events. The Pennsylvanian is a subperiod of the Carboniferous period lasting from roughly   to  Ma (million years ago The Triassic is a geologic period and system that extends from about 251 to 199 Ma (million years ago The Permian–Triassic (P–Tr extinction event, informally known as the Great Dying, was an Extinction event that occurred, and 70 percent of terrestrial The Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life" Axis scale: millions of years ago.

The Permian^[4] is a geologic period that extends from 299. 0 ± 0. 8 Ma to 251. Annum is one form of the Latin noun meaning Year, not a form normally used for derivatives in modern languages the accusative singular 0 ± 0. 4 Ma (million years before the present) (ICS, 2004)^[5]. The International Commission on Stratigraphy (ICS, sometimes referred to by the unofficial " International Stratigraphic Commission " is a daughter or major Subcommittee It is the last period of the Paleozoic Era. The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life" The Permian period was named after the city of Perm, Russia by Scottish geologist Roderick Murchison in 1841. Perm (Пермь pʲɛrmʲ is a city and administrative center of Perm Krai, Russia. Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending Sir Roderick Impey Murchison 1st Baronet KCB FRS ( 19 February, 1792 &ndash 22 October, 1871) was an influential

Subdivisions

The three primary subdivisions of the Permian Period are given below from youngest to oldest, and include faunal stages also from youngest to oldest. Additional age/stage equivalents or subdivisions are given in parentheses. Epoch and age refer to time, and equivalents series and stage refer to the rocks.

Lopingian Epoch

Changhsingian Age (Djulfian/Ochoan/Dewey Lake/Zechstein)

Wuchiapingian Age (Dorashamian/Ochoan/Longtanian/Rustler/Salado/Castile/Zechstein)

Guadalupian Epoch

Capitanian Age (Kazanian/Zechstein)

Wordian Age (Kazanian/Zechstein)

Roadian Age (Ufimian/Zechstein)

Cisuralian Epoch

Kungurian Age (Irenian/Filippovian/Leonard/Rotliegendes)

Artinskian Age (Baigendzinian/Aktastinian/Rotliegendes)

Sakmarian Age (Sterlitamakian/Tastubian/Leonard/Wolfcamp/Rotliegendes)

Asselian Age (Krumaian/Uskalikian/Surenian/Wolfcamp/Rotliegendes)

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. Mean sea level (MSL is the average (mean height of the Sea, with reference to a suitable reference surface Not to be confused with Land mass. A landmass is a large continuous area of land. Pangaea, Pangæa or Pangea (pænˈdʒiːə from παν pan, meaning entire, and Γαῖα Gaea, meaning Earth in One continent, even a very large one, has a smaller shoreline than six to eight smaller ones with the same total area. 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. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 Pangaea, Pangæa or Pangea (pænˈdʒiːə from παν pan, meaning entire, and Γαῖα Gaea, meaning Earth in 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 equator (sometimes referred to colloquially as "the Line") is the intersection of the Earth 's surface with the plane perpendicular to the Panthalassa ( Greek, meaning 'all seas' also known as the Panthalassic Ocean, was the vast global Ocean that surrounded the Supercontinent The Cimmeria continent rifted away from Gondwana and drifted north to Laurasia, causing the Paleo-Tethys to shrink. The Cimmerian Plate is an ancient Tectonic plate that comprises parts of present-day Anatolia, Iran, Afghanistan, Tibet, Indochina In Geology, a rift is a place where the Earth 's crust and Lithosphere are being pulled apart and is an example of Extensional tectonics Gondwana (ɡɒnˈdwɑːnə originally Gondwanaland) was a southern Supercontinent that existed about 500 to 200 Ma ago Laurasia (lɔˈreɪʃiə lɔˈreɪʒə was a Supercontinent that most recently existed as a part of the split of the Pangaean supercontinent in the late Mesozoic The Paleo-Tethys Ocean was an ancient Paleozoic Ocean. It was located between the Paleocontinent Gondwana and the so called Hunic terranes A new ocean was growing on its southern end, the Tethys Ocean, an ocean that would dominate much of the Mesozoic Era. The Tethys Ocean was a Mesozoic era Ocean that existed between the continents of Gondwana and Laurasia before the opening of the Indian The Mesozoic Era is one of three geologic eras of the Phanerozoic eon. Large continental landmasses create climates with extreme variations of heat and cold ("continental climate") and monsoon conditions with highly seasonal rainfall patterns. Continental climate is a Climate that is characterized by Winter Temperatures cold enough to support a fixed period of Snow cover each Year A monsoon is a seasonal prevailing wind which lasts for several months Deserts seem to have been widespread on Pangaea. A desert is a Landscape or region that receives very little precipitation. Such dry conditions favored gymnosperms, plants with seeds enclosed in a protective cover, over plants such as ferns that disperse spores. Gymnosperm (Gymnospermae are a group of Spermatophyte seed-bearing Plants with Ovules on the edge or blade of an open Sporophyll, which are A seed (in some plants referred to as a kernel) is a small embryonic Plant enclosed in a covering called the seed coat usually with some stored A fern is any one of a group of about 20000 Species of Plants classified in the phylum or division Pteridophyta, also known as Filicophyta In Biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions The first modern trees (conifers, ginkgos and cycads) appeared in the Permian. A tree is a perennial Woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or Ginkgo is a genus of highly unusual non-flowering plants with one extant species G Cycads are a group of Seed plants characterized by a large crown of compound leaves and a stout trunk.

Three general areas are especially noted for their 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. Riphean redirects here For the time period see Riphean stage The Ural Mountains (Ура́льские го́ры Uralskiye The Permian Basin is a Sedimentary basin largely contained in the western part of the U The United States of America —commonly referred to as the Texas ( is a state geographically located in the South Central United States and is also known as the Lone Star State.

Climate

As the Permian opened, the Earth was still in the grip of an ice age, so the polar regions were covered with deep layers of ice. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 An ice age is a period of long-term reduction in the Temperature of the Earth 's surface and atmosphere resulting in an expansion of continental Ice sheets Glaciers continued to cover much of Gondwanaland, as they had during the late Carboniferous. "Glacial" and "Glaciation" redirect here For the geological periods see Glacial period. Gondwana (ɡɒnˈdwɑːnə originally Gondwanaland) was a southern Supercontinent that existed about 500 to 200 Ma ago The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359

The Permian Period, at the end of the Paleozoic era, marked a great changes in the Earth's climate and appearance. Towards the middle of the period the climate became warmer and milder, the glaciers receded, and the continental interiors became drier. Much of the interior of Pangaea was probably arid, with great seasonal fluctuations (wet and dry seasons), because of the lack of the moderating effect of nearby bodies of water. This drying tendency continued through to the late Permian, along with alternating warming and cooling periods.

Life

Dimetrodon and Eryops- Early Permian, North America

Edaphosaurus pogonias - Early Permian

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. Dimetrodon (daɪˈmɛtɹəʊˌdɒn meaning "two measures of teeth" was a Predatory Synapsid (' Mammal-like reptile ' Genus Eryops (ˈɛəriːɒps meaning "drawn-out face" because most of its skull was in front of its eyes ( Greek eryein = drawn-out + ops Edaphosaurus (Greek earth lizard; from edaphos / εδαφος, "ground" and sauros / σαυρος, "lizard" Titanophoneus potens ("Potent titanic murderer" was a carnivorous Therapsid of the Dinocephalia group related to the Estemmenosuchidae Ulemosaurus svijagensis was a Dinocephalian Synapsid related distantly to Estemenosuchids but lived 250 MYA that is 5 million years later than FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. Molluscs are animals belonging to the phylum Mollusca. There are around 250000 extant Species within the phylum with an estimated 70000 Echinoderms (Phylum Echinodermata) are a phylum of marine Animals (including Sea stars) Brachiopods (from Latin brachium, arm + New Latin -poda, foot are a small phylum of Benthic Invertebrates Also 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. An invertebrate is an Animal lacking a Vertebral column. The group includes 98% of all animal Species — all animals except those in the Chordate The fusulinids are an extinct group of Foraminiferan protozoa Protists (ˈproʊtɨst are a diverse group of eukaryotic Microorganisms Historically protists were treated as the kingdom Protista but this The Foraminifera, ("Hole Bearers" or forams for short are a large group of Amoeboid Protists with reticulating Pseudopods fine Ammonites are an extinct group of marine animals of the subclass Ammonoidea in the class Cephalopoda phylum The cephalopods ( Greek plural (kephalópoda "head-feet" are the Mollusc class Cephalopoda characterized by Nautilus (from Greek ναυτίλος, 'sailor' is the common name of any marine creatures of the Cephalopod family Nautilidae, the sole By the close of the Permian, trilobites and a host of other marine groups became extinct

Terrestrial biota

Terrestrial life in the Permian included diverse plants, fungi, arthropods, and various types of tetrapods. Trilobites ("three-lobes" are extinct Arthropods that form the class Trilobita. Plants are living Organisms belonging to the kingdom Plantae. A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " Permian Tetrapods were amphibians and reptiles that lived during the Permian Period. The period saw a massive desert covering the interior of the Pangaea. A desert is a Landscape or region that receives very little precipitation. Pangaea, Pangæa or Pangea (pænˈdʒiːə from παν pan, meaning entire, and Γαῖα Gaea, meaning Earth in The warm zone spread in the northern hemisphere, where extensive dry desert appeared. The rock 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 there was a major transition in vegetation. The swamp-loving lycopod trees of the Carboniferous, such as Lepidodendron and Sigillaria, were replaced by the more advanced conifers, which were better adapted to the changing climatic conditions. The Division Lycopodiophyta (sometimes called Lycophyta) is a tracheophyte subdivision of the Kingdom Plantae It is the oldest extant (living Lepidodendron (also known as the "Scale tree" is an Extinct Genus of primitive vascular arborescent ( Tree -like Plant Sigillaria is a genus of extinct spore-bearing arborescent (tree-like plants which flourished in the Late Carboniferous period but dwindled to extinction in the early The Permian saw the radiation of many important conifer groups, including the ancestors of many present-day families. Lycopods and swamp forests still dominated the South China continent because it was an isolated continent and it sat near or at the equator. A swamp is a Wetland featuring temporary or permanent inundation of large areas of land by shallow bodies of water A forest is an area with a high density of Trees There are many definitions of a forest based on various criteria South China continent, also known as South China craton (or the South Chinese craton or as Yangtze craton, was an ancient Continent ( Craton Oxygen levels were probably high there. The ginkgos and cycads also appeared during this period. Ginkgo is a genus of highly unusual non-flowering plants with one extant species G Cycads are a group of Seed plants characterized by a large crown of compound leaves and a stout trunk. Rich forests were present in many areas, with a diverse mix of plant groups.

Insects of the Permian

By the Pennsylvanian and well into the Permian, by far the most successful were primitive relatives of cockroaches. The Pennsylvanian is a subperiod of the Carboniferous period lasting from roughly   to  Ma (million years ago Blattoptera is a name given to various "roachid" fossil insects related to Cockroaches Mantises and Termites, and of general cockroach-like appearance 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 a gizzard and efficient mouth parts, gave it formidable advantages over other herbivorous animals. Chitin ( C 8 H 13 O 5 N)n (ˈkaɪtən is a long-chain Polymer of a N-acetylglucosamine About 90% of insects were cockroach-like insects ("Blattopterans"). ^[6]

The dragonflies Odonata were the dominant aerial predator and probably dominated terrestrial insect predation as well. Anisoptera redirects here For the genus of trees see Anisoptera (tree. True Odonata appeared in the Permian^[7][8] and all are amphibious. Their prototypes are the oldest winged fossils,^[9] go back to the Devonian, and are different from other wings in every way. The Devonian is a geologic period and system of the Paleozoic era spanning from to  million years ago. ^[10] 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. The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359 ^[11] A number of important new insect groups appeared at this time, including the Coleoptera (beetles) and Diptera (flies). Beetles are the group of Insects with the largest number of known Species. True flies are Insects of the Order Diptera ( Greek: di = two and pteron = wing possessing a single pair of

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. The pelycosaurs (from Greek πηλυξ pelyx meaning 'bowl' and σαυρος sauros meaning 'lizard' were primitive Late Paleozoic Prehistoric amphibian Amphibians (class Amphibia such as Frogs Toads Salamanders Newts Gymnophiona, Sirens and Therapsids are an order of Synapsids (Class Synapsida Traditionally synapsids were referred to as Reptiles and were known as Dinocephalia are a clade of large early therapsids that flourished during the Middle Permian Gorgonopsia ("Gorgon face" is a suborder of Therapsid Synapsids Their name is a reference to the Gorgons of Greek mythology The Dicynodontia are a Taxon of Therapsids or Mammal-like reptiles. Towards the very end of the Permian the first archosaurs appeared, a group that would give rise to the dinosaurs in the following period. Archosauriformes ( Greek for 'ruling lizards' and 'form' are a clade of Diapsid Reptiles that developed from Archosauromorph ancestors some time The Triassic is a geologic period and system that extends from about 251 to 199 Ma (million years ago Also appearing at the end of the Permian were the first cynodonts, which would go on to evolve into mammals during the Triassic. Cynodonts, or 'dog teeth' are a taxon of Therapsids which includes modern mammals and their extinct close relatives Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Another group of therapsids, the therocephalians (such as Trochosaurus), arose in the Middle Permian. Therocephalians are an extinct lineage of Eutheriodont Therapsids that lived throughout the middle and late Permian and into the Triassic Trochosaurus is an extinct genus of Mammal-like reptile. It belong to a synapsid suborder called therocephalia 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. Megafauna are species of large Animals ( Greek μεγας large + modern Latin fauna animal Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell A carnivore (ˈkɑrnɪvɔər meaning 'meat eater' ( Latin carne meaning 'flesh' and vorare meaning 'to devour' is any animal with a diet consisting It was the high tide of the anapsides in the form of the massive Pareiasaurs and host of smaller, generally lizzard-like groups. An anapsid is an Amniote whose skull does not have openings near the temples While "anapsid reptiles" or "anapsida" are traditionally The Pareiasaurs - family Pareiasauridae - are a group of medium-sized to large herbivorous Anapsid Reptiles that flourished during the A group of small reptiles, the diapsids started to abound. Diapsids ("two arches" are a group of Reptiles that developed two holes ( Temporal fenestra) in each side of their Skulls about 300 Million 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. Synapsids ('fused arch' also known as theropsids ('beast face' are a class of Animals that includes Mammals and everything closer to mammals than Dimetrodon (daɪˈmɛtɹəʊˌdɒn meaning "two measures of teeth" was a Predatory Synapsid (' Mammal-like reptile ' Genus 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. Temnospondyli (from Greek τεμνειν temnein = "to cut" + σπονδυλως spondulos = "vertebra" are an important and extremely diverse Lepospondyli are a group of small but diverse Carboniferous to early Permian Amphibians Six different Clades are known the Acherontiscidae Batrachosauria ("Frog Saurians" is a name given either to very reptile-like amphibians dating from the Carboniferous and Permian periods or to amniotes

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. A genus (plural genera from Γένος Latin genus "descent family type gender" is a low-level Taxonomic FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system.

Main article: Permian–Triassic extinction event

The Permian ended with the most extensive extinction event recorded in paleontology: the Permian-Triassic extinction event. The Permian–Triassic (P–Tr extinction event, informally known as the Great Dying, was an Extinction event that occurred, and 70 percent of terrestrial An extinction event (also known as mass extinction; extinction-level event, ELE is a sharp decrease in the number of Species in a relatively short period Palaeontology redirects here For the Scientific journal, see Palaeontology (journal. The Permian–Triassic (P–Tr extinction event, informally known as the Great Dying, was an Extinction event that occurred, and 70 percent of terrestrial 90% to 95% of marine species became extinct, as well as 70% of all land organisms. In Biology and Ecology, extinction is the cessation of existence of a Species or group of taxa. On an individual level, perhaps as many as 99. 5% of separate organisms died as a result of the event. ^[12]

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. A flood basalt or trap basalt is the result of a giant Volcanic eruption or series of Eruptions that coats large stretches of land or the Ocean floor The Siberian Traps (Сибирские траппы form a Large igneous province in Siberia. 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, not enough to kill off 95% of life.

Another hypothesis involves ocean venting of hydrogen sulfide gas. Hydrogen sulfide (or hydrogen sulphide) is the Chemical compound with the formula H 2 S. Portions of deep ocean 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 zone, the gas can rise into the atmosphere. Oceanic anoxic events or Anoxic events occur when the Earth 's Oceans become completely depleted of oxygen (O2 below the surface levels

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). OZONE is an object oriented Operating system written in the C programming language. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays 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. A supernova (plural supernovae or supernovas) is a stellar Explosion.

Trilobites, which had thrived since Cambrian times, finally became extinct before the end of the Permian. Trilobites ("three-lobes" are extinct Arthropods that form the class Trilobita. The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with

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. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. The Ohio State University ( OSU) is a Coeducational public Research university in the state of Ohio. A meteorite is a natural object originating in Outer space that survives an impact with the Earth 's surface In the broadest sense the term impact crater can be applied to any depression natural or manmade resulting from the high velocity impact of a projectile with larger body Wilkes Land crater is an informal term that may apply to two separate cases of conjectured giant Impact craters hidden beneath the Ice cap of Wilkes Land 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. For a topic outline on this subject see List of basic Australia topics. In Geology, a supercontinent is a Landmass comprising more than one Continental core or Craton. Gondwana (ɡɒnˈdwɑːnə originally Gondwanaland) was a southern Supercontinent that existed about 500 to 200 Ma ago Levels of iridium and quartz fracturing in the Permian-Triassic layer do not approach those of the Cretaceous-Tertiary boundary layer. The K-T boundary is a geological signature usually a thin band dated to 65 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.

Thriving also, were the early ancestors to mammals (synapdia), 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.

The warm zone spread in the northern hemisphere, where extensive dry desert appeared. The rock 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. The old types of plants and animals died out.

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. Pangaea, Pangæa or Pangea (pænˈdʒiːə from παν pan, meaning entire, and Γαῖα Gaea, meaning Earth in A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor

See also

• List of fossil sites (with link directory)
• Permian tetrapods

Notes

References

• Ogg, Jim; June, 2004, Overview of Global Boundary Stratotype Sections and Points (GSSP's) http://www.stratigraphy.org/gssp.htm Accessed April 30, 2006. Events 313 - Roman emperor Licinius unifies the entire Eastern Roman Empire under his rule Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar.
• 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. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  

External links

• University of California offers a more modern Permian stratigraphy
• Classic Permian strata in the Glass Mountains of the Permian Basin
• International Commission on Stratigraphy (ICS). Geologic Time Scale 2004. Retrieved on September 19, 2005.
• Examples of Permian Fossils