Permian Period 299–251 million years ago PreЄ Є O S D C P T J K Pg N
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 60 m (200 ft) in early Permian; plummeting during the middle Permian to a constant −20 m (−65.6 ft) in the late Permian.[4]

The Permian is a geologic period and system which extends from 299.0 ± 0.8 to 251.0 ± 0.4 Ma (Million years ago).^[5] It is the last period of the Paleozoic Era, following the Carboniferous Period and preceding the Triassic Period of the Mesozoic Era. It was first introduced in 1841 by geologist Sir Roderick Murchison, and is named after the Perm Krai in Russia, where strata from the period was originally found.

The Permian witnessed the diversification of the early amniotes into the ancestral groups of the mammals, turtles, lepidosaurs and archosaurs. The world at the time was dominated by a single supercontinent known as Pangaea, surrounded by a global ocean called Panthalassa. The extensive rainforests of the Carboniferous had disappeared, leaving behind vast regions of arid desert within the continental interior. Reptiles, who could better cope with these dryer conditions, rose to dominance in lieu of their amphibian ancestors. The Permian Period (along with the Paleozoic Era) ended with the largest mass extinction in Earth's history, in which nearly 90% of marine species and 70% of terrestrial species died out.^[6] It would take well into the Triassic for life to recover from this catastrophe.

Discovery[link]

The term "Permian" was introduced into geology in 1841 by Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil.^[7] 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. The region now lies in the Perm Krai of Russia.

ICS Subdivisions[link]

Official (ICS, 2004^[8]) 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 Mya - 251.0 ± 0.4 Mya]^[9]

• Changhsingian (Changxingian) [253.8 ± 0.7 Mya - 251.0 ± 0.4 Mya]
• Wuchiapingian (Wujiapingian) [260.4 ± 0.7 Mya - 253.8 ± 0.7 Mya]
• Others:
  • Waiitian (New Zealand) [260.4 ± 0.7 Mya - 253.8 ± 0.7 Mya]
  • Makabewan (New Zealand) [253.8 - 251.0 ± 0.4 Mya]
  • Ochoan (North American) [260.4 ± 0.7 Mya - 251.0 ± 0.4 Mya]

Middle Permian, or Guadalupian epoch [270.6 ± 0.7 - 260.4 ± 0.7 Mya]^[10]

• Capitanian stage [265.8 ± 0.7 - 260.4 ± 0.7 Mya]
• Wordian stage [268.0 ± 0.7 - 265.8 ± 0.7 Mya]
• Roadian stage [270.6 ± 0.7 - 268.0 ± 0.7 Mya]
• Others:
  • Kazanian or Maokovian (European) [270.6 ± 0.7 - 260.4 ± 0.7 Mya]^[11]
  • Braxtonian stage (New Zealand) [270.6 ± 0.7 - 260.4 ± 0.7 Mya]

Lower / Early Permian or Cisuralian epoch [299.0 ± 0.8 - 270.6 ± 0.7 Mya]^[12]

• Kungurian (Irenian / Filippovian / Leonard) stage [275.6 ± 0.7 - 270.6 ± 0.7 Mya]
• Artinskian (Baigendzinian / Aktastinian) stage [284.4 ± 0.7 - 275.6 ± 0.7 Mya]
• Sakmarian (Sterlitamakian / Tastubian / Leonard / Wolfcamp) stage [294.6 ± 0.8 - 284.4 ± 0.7 Mya]
• Asselian (Krumaian / Uskalikian / Surenian / Wolfcamp) stage [299.0 ± 0.8 - 294.6 ± 0.8 Mya]
• Others:
  • Telfordian (New Zealand) [289 - 278]
  • Mangapirian (New Zealand) [278 - 270.6]

Oceans[link]

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[link]

Geography of the Permian world

During the Permian, all the Earth's major land masses 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[link]

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. Glaciers receded around the mid-Permian period as the climate gradually warmed, drying the continent's interiors.^[13] In the late Permian period, the drying continued although the temperature cycled between warm and cool cycles.^[13]

Life[link]

Hercosestria cribrosa, a reef-forming productid brachiopod (Middle Permian, Glass Mountains, Texas).

Marine biota[link]

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[link]

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 South China.^[14]

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[link]

By the Pennsylvanian and well into the Permian, by far the most successful were primitive relatives of cockroaches. Six fast legs, four well developed folding wings, fairly good eyes, long, well developed antennae (olfactory), an omnivorous digestive system, a receptacle for storing sperm, a chitin-based exoskeleton 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 at the start of the Permian were cockroach-like insects ("Blattopterans").^[15]

Primitive forms of dragonflies (Odonata) were the dominant aerial predators and probably dominated terrestrial insect predation as well. True Odonata appeared in the Permian^[16][17] and all are effectively amphibious (aquatic immature stages, and terrestrial adults), as are all modern odonates. Their prototypes are the oldest winged fossils,^[18] go back to the Devonian, and are different in several respects from the wings of other insects.^[19] Fossils suggest they may have possessed many modern attributes even by the late Carboniferous, and it is possible that they captured small vertebrates, for some species had a wing span of 71 cm.^[20] Several other insect groups appeared during the Permian, including the Coleoptera (beetles) and Hemiptera (true bugs).

Synapsid and amphibian fauna[link]

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 anapsids 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 members 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[link]

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.^[21][22] Recovery from the Permian-Triassic extinction event was protracted; on land, ecosystems took 30M years to recover.^[23]

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.^[13]

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.^{[citation needed]}

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.^[24] 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.^{[citation needed]}

An even more speculative hypothesis is that intense radiation from a nearby supernova was responsible for the extinctions.^{[citation needed]}

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 The Ohio State University reported evidence for a possible huge meteorite crater (Wilkes Land crater) with a diameter of around 500 kilometers in Antarctica.^[25] 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–Paleogene 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.^{[citation needed]}

Many scientists argue 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.^{[citation needed]}

See also[link]

• List of fossil sites (with link directory)
• Olson's Extinction
• Permian tetrapods

Notes[link]

References[link]

• Ogg, Jim; June, 2004, Overview of Global Boundary Stratotype Sections and Points (GSSP's) http://www.stratigraphy.org/gssp.htm Accessed April 30, 2006.

External links[link]

Wikimedia Commons has media related to: Permian

• 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. http://www.stratigraphy.org/. Retrieved September 19, 2005. 
• Examples of Permian Fossils
• Fossil of Giant Permian Amphibian

James "Boobie" Miles (born April 16, 1970 in Houston, Texas) was a high school football tail back, and was a primary subject in the book Friday Night Lights: A Town, a Team, and a Dream by H.G. Bissinger, and the movie inspired by the book. He attended Permian High School in Odessa, Texas.

Miles is a major figure in Bissinger's book as one of the top high school running backs in Texas. He was sought by dozens of top college football schools, but his promising career was derailed by a knee injury.

Early life[link]

Miles was born en route to St. Luke's Hospital in Houston with a police escort on April 16, 1970. He lived with his parents until he was three when his mother left him with his maternal grandmother in Houston and moved permanently to Oklahoma without him. Around the age of five Miles went to live with his father, James Sr. The elder Miles was working two jobs, as a truck driver and printing-plant laborer. His father lost custody of Boobie when he started dating a woman who, Boobie claims, physically harmed him. He was placed in a foster home in the Houston area, and eight months later he was put in the care of his uncle L.V. Miles in Odessa, Texas. The two shared the house with L.V.'s wife, Ruby, and her three daughters.^[1]

Miles started playing football for the Vikings, a Pop Warner football team that L.V. coached.^[1]

High school football career[link]

In 1987 Miles rushed for 1,385 yards. Expectations were high every year at Permian High School and in 1988 the Associated Press, in its preseason predictions, had chosen Permian to win the state title based partly on the play of Miles.^[1] From the spring through the early fall of '88 Miles was heavily recruited by numerous top football schools. Letters came from Notre Dame, Nebraska, Houston, Texas A&M, Clemson, Texas Tech, Oklahoma, Oklahoma State, LSU, SMU, UCLA and Arkansas.

However in a pre-season scrimmage against the Amarillo Palo Duro Dons, Miles' leg was caught in the artificial turf when he planted his left leg to stiff-arm a tackler; another player then fell on it from the side. The next day he was examined by a local doctor. The initial diagnoses of the injury was that is was only a sprained ligament. Four days later an orthopedic surgeon, Dr. Thurston E. Dean, examined Miles and felt the injury was severe enough to require arthroscopic surgery. The surgery was performed the day before Permian's season opener against El Paso Austin.^[1] Miles had severely torn the anterior cruciate ligament. He had also torn the cartilage in his left knee. Miles was given the option of immediate reconstructive surgery, which Dean had recommended, or a program of rehabilitation. Rehab would allow Miles to play football with a knee brace. Both Boobie and L.V. opted for the brace.

Miles returned against Abilene High School, however left the game limping with a cramp after only a handful of carries. The next week against Midland Lee High School, Permian lost, with Miles threatening to quit the team at halftime for his lack of playing time.^[1] Miles spent the rest of the season on bench, and in November 1988 Dean performed reconstructive surgery on his knee. After rehabilitation from the surgery Miles lost much of the speed that had made him an effective running back.

After his injury Miles was the target of racial epithets and was told he "should be shot like an animal" after being injured.^[2] After a fight with L.V., Miles moved out and with Chris Comer taking his place at running back, Miles did not play for Permian High School again.^[1]

[edit] Friday Night Lights

In 1990 a non-fiction book written by H. G. Bissinger follows the story of the 1988 Permian High School Panthers football team from Odessa as they made a run towards the Texas state championship. Miles was a key figure in the book. In 2002, Sports Illustrated named Friday Night Lights the fourth-greatest book ever written about sports.^[3]

A movie version of Friday Night Lights was made and then released in the United States on October 6, 2004. It starred Billy Bob Thornton as Permian Coach Gary Gaines. The film was a box office and critical success and, in turn, spawned an NBC television series of the same name, which began airing in October 2006. Boobie was played by Derek Luke.

After high school[link]

Miles attended Ranger College for a year and played as a fullback before flunking out and has since had trouble holding jobs. He then spent some time playing semi-pro football in Culpepper, Virginia though he was never able to regain his high school form or confidence in his ability. He regrets trying to play on his injured knee before having surgery to repair it.^[4]

He has two children who live in Midland with their mother. As of August 2009 Miles lives in Dallas and is not working. In May 2009, he was charged with aggravated assault. Police said he struck his stepbrother repeatedly in the head with a beer bottle. He received a sentence of five years' deferred probation in district court. The charge will be dismissed if he successfully completes probation.^[5]

In 2012, Buzz Bissinger published a 34 page afterward called After Friday Night Lights^[6], which has Bissinger visiting with Miles and discussing their 25 year friendship.

References[link]

External links[link]

	Texas portal
	Biography portal
	American football portal

• Official Friday Night Lights Book Website
• Salgado blocked for famous Boobie Miles in Odessa
• West Texas Prep Hero Is Striving For New Lease On Life
• 1987 Permian vs. Arlington Video
• Friday Night Lights: Twenty Years After Their Iconic Season, Where are They Now?