In the geologic timescale, the Artinskian is an age or stage of the Permian. It is a subdivision of the Cisuralian series; the Artinskian lasted between 283.5 million years ago. It was followed by the Kungurian; the Artinskian is named after the small Russian city of Arti, situated in the southern Ural mountains, about 200 km southwest of Yekaterinburg. The stage was introduced into scientific literature by Alexander Karpinsky in 1874; the base of the Artinskian stage is defined as the place in the stratigraphic record where fossils of conodont species Sweetognathus whitei and Mesogondolella bisselli first appear. As of 2009, there was no agreement yet on a global reference profile for the base of the Artinskian; the top of the Artinskian is defined as the place in the stratigraphic record where fossils of conodonts Neostreptognathodus pnevi and Neostreptognathodus exculptus first appear. GeoWhen Database - Artinskian Upper Paleozoic stratigraphic chart at the website of the subcommission for stratigraphic information of the ICS
The Tethys Ocean called the Tethys Sea or the Neotethys, was an ocean during much of the Mesozoic Era located between the ancient continents of Gondwana and Laurasia, before the opening of the Indian and Atlantic oceans during the Cretaceous Period. The name stems from the mythological Greek sea goddess Tethys and consort of Oceanus, mother of the great rivers and fountains of the world and of the Oceanid sea nymphs; the eastern part of the Tethys Ocean is sometimes referred to as Eastern Tethys. The western part of the Tethys Ocean is called Tethys Sea, Western Tethys Ocean, or Paratethys or Alpine Tethys Ocean; the Black and Aral seas are thought to be its crustal remains, though the Black Sea may, in fact, be a remnant of the older Paleo-Tethys Ocean. The Western Tethys was not a single open ocean, it covered many small plates, Cretaceous island arcs, microcontinents. Many small oceanic basins were separated from each other by continental terranes on the Alboran and Apulian plates; the high sea level in the Mesozoic flooded most of these continental domains.
As theories have improved, scientists have extended the "Tethys" name to refer to three similar oceans that preceded it, separating the continental terranes: in Asia, the Paleo-Tethys, Meso-Tethys, Ceno-Tethy are recognized. Neither Tethys Ocean should be confused with the Rheic Ocean, which existed to the west of them in the Silurian Period. To the north of the Tethys, the then-land mass was called Angaraland and to the south of it, it was called Gondwanaland. From the Ediacaran into the Devonian, the Proto-Tethys Ocean existed and was situated between Baltica and Laurentia to the north and Gondwana to the south. From the Silurian through the Jurassic periods, the Paleo-Tethys Ocean existed between the Hunic terranes and Gondwana. Over a period of 400 million years, continental terranes intermittently separated from Gondwana in the Southern Hemisphere to migrate northward to form Asia in the Northern Hemisphere. About 250 Mya, during the Triassic, a new ocean began forming in the southern end of the Paleo-Tethys Ocean.
A rift formed along the northern continental shelf of Southern Pangaea. Over the next 60 million years, that piece of shelf, known as Cimmeria, traveled north, pushing the floor of the Paleo-Tethys Ocean under the eastern end of northern Pangaea; the Tethys Ocean formed between Cimmeria and Gondwana, directly over where the Paleo-Tethys used to be. During the Jurassic period about 150 Mya, Cimmeria collided with Laurasia and stalled, so the ocean floor behind it buckled under, forming the Tethyan Trench. Water levels rose, the western Tethys shallowly covered significant portions of Europe, forming the first Tethys Sea. Around the same time and Gondwana began drifting apart, opening an extension of the Tethys Sea between them which today is the part of the Atlantic Ocean between the Mediterranean and the Caribbean; as North and South America were still attached to the rest of Laurasia and Gondwana the Tethys Ocean in its widest extension was part of a continuous oceanic belt running around the Earth between about latitude 30°N and the Equator.
Thus, ocean currents at the time around the Early Cretaceous ran differently from the way they do today. Between the Jurassic and the Late Cretaceous, which started about 100 Mya, Gondwana began breaking up, pushing Africa and India north across the Tethys and opening up the Indian Ocean; as these land masses crowded in on the Tethys Ocean from all sides, to as as the Late Miocene, 15 Mya, the ocean continued to shrink, becoming the Tethys Seaway or second Tethys Sea. Throughout the Cenozoic, global sea levels fell hundreds of meters, the connections between the Atlantic and the Tethys closed off in what is now the Middle East. During the Oligocene, large parts of central and eastern Europe were covered by a northern branch of the Tethys Ocean, called the Paratethys; the Paratethys was separated from the Tethys with the formation of the Alps, Dinarides and Elburz mountains during the Alpine orogeny. During the late Miocene, the Paratethys disappeared, became an isolated inland sea. In 1885, the Austrian palaeontologist Melchior Neumayr deduced the existence of the Tethys Ocean from Mesozoic marine sediments and their distribution, calling his concept Zentrales Mittelmeer and described it as a Jurassic seaway, which extended from the Caribbean to the Himalayas.
In 1893, the Austrian geologist Eduard Suess proposed the theory that an ancient and extinct inland sea had once existed between Laurasia and the continents which formed Gondwana II. He named it the Tethys Sea after the Greek sea goddess Tethys, he provided evidence for his theory using fossil records from the Africa. He proposed the concept of Tethys in his four-volume work Das Antlitz der Erde. In the following decades during the 20th century, "mobilist" geologists such as Uhlig and Daque regarded Tethys as a large trough between two supercontinents which lasted from the late Palaeozoic until continental fragments derived from Gondwana obliterated it. After World War II, Tethys was described as a triangular ocean with a wide eastern end. From 1920s to the 1960s, "fixist" geologists, regarded Tethys as a composite trough, which evolved through a series of orogenic cycles, they used the terms'Paleotethys','Mesotethys', and'Neotethys' for the Caledonian and Alpine orogenies, respe
The Carboniferous is a geologic period and system that spans 60 million years from the end of the Devonian Period 358.9 million years ago, to the beginning of the Permian Period, 298.9 Mya. The name Carboniferous means "coal-bearing" and derives from the Latin words carbō and ferō, was coined by geologists William Conybeare and William Phillips in 1822. Based on a study of the British rock succession, it was the first of the modern'system' names to be employed, reflects the fact that many coal beds were formed globally during that time; the Carboniferous is treated in North America as two geological periods, the earlier Mississippian and the Pennsylvanian. Terrestrial animal life was well established by the Carboniferous period. Amphibians were the dominant land vertebrates, of which one branch would evolve into amniotes, the first terrestrial vertebrates. Arthropods were very common, many were much larger than those of today. Vast swaths of forest covered the land, which would be laid down and become the coal beds characteristic of the Carboniferous stratigraphy evident today.
The atmospheric content of oxygen reached its highest levels in geological history during the period, 35% compared with 21% today, allowing terrestrial invertebrates to evolve to great size. The half of the period experienced glaciations, low sea level, mountain building as the continents collided to form Pangaea. A minor marine and terrestrial extinction event, the Carboniferous rainforest collapse, occurred at the end of the period, caused by climate change. In the United States the Carboniferous is broken into Mississippian and Pennsylvanian subperiods; the Mississippian is about twice as long as the Pennsylvanian, but due to the large thickness of coal-bearing deposits with Pennsylvanian ages in Europe and North America, the two subperiods were long thought to have been more or less equal in duration. In Europe the Lower Carboniferous sub-system is known as the Dinantian, comprising the Tournaisian and Visean Series, dated at 362.5-332.9 Ma, the Upper Carboniferous sub-system is known as the Silesian, comprising the Namurian and Stephanian Series, dated at 332.9-298.9 Ma.
The Silesian is contemporaneous with the late Mississippian Serpukhovian plus the Pennsylvanian. In Britain the Dinantian is traditionally known as the Carboniferous Limestone, the Namurian as the Millstone Grit, the Westphalian as the Coal Measures and Pennant Sandstone; the International Commission on Stratigraphy faunal stages from youngest to oldest, together with some of their regional subdivisions, are: A global drop in sea level at the end of the Devonian reversed early in the Carboniferous. There was a drop in south polar temperatures; these conditions had little effect in the deep tropics, where lush swamps to become coal, flourished to within 30 degrees of the northernmost glaciers. Mid-Carboniferous, a drop in sea level precipitated a major marine extinction, one that hit crinoids and ammonites hard; this sea level drop and the associated unconformity in North America separate the Mississippian subperiod from the Pennsylvanian subperiod. This happened about 323 million years ago, at the onset of the Permo-Carboniferous Glaciation.
The Carboniferous was a time of active mountain-building as the supercontinent Pangaea came together. The southern continents remained tied together in the supercontinent Gondwana, which collided with North America–Europe along the present line of eastern North America; this continental collision resulted in the Hercynian orogeny in Europe, the Alleghenian orogeny in North America. In the same time frame, much of present eastern Eurasian plate welded itself to Europe along the line of the Ural Mountains. Most of the Mesozoic supercontinent of Pangea was now assembled, although North China, South China continents were still separated from Laurasia; the Late Carboniferous Pangaea was shaped like an "O." There were two major oceans in the Carboniferous—Panthalassa and Paleo-Tethys, inside the "O" in the Carboniferous Pangaea. Other minor oceans were shrinking and closed - Rheic Ocean, the small, shallow Ural Ocean and Proto-Tethys Ocean. Average global temperatures in the Early Carboniferous Period were high: 20 °C.
However, cooling during the Middle Carboniferous reduced average global temperatures to about 12 °C. Lack of growth rings of fossilized trees suggest a lack of seasons of a tropical climate. Glaciations in Gondwana, triggered by Gondwana's southward movement, continued into the Permian and because of the lack of clear markers and breaks, the deposits of this glacial period are referred to as Permo-Carboniferous in age; the cooling and drying of the climate led to the Carboniferous Rainforest Collapse during the late Carboniferous. Tropical rainforests fragmented and were devastated by climate change. Carboniferous rocks in Europe and eastern North America consist of a repeated sequence of limestone, sandstone and coal beds. In North America, the early Carboniferous is marine
The Fusulinida is an extinct order within the Foraminifera in which the tests are composed of packed, secreted microgranular calcite. Like all Forams, they are single-celled organisms. In advanced forms the test wall is differentiated into two or more layers. Loeblich and Tappan, 1988, gives a range from the Lower Silurian to the Upper Permian, with the fusulinid foraminifera going extinct with the Permian–Triassic extinction event. While the latter is true, a more supported. Thirteen superfamilies are presently recognised, based on taxa included in the three superfamilies given in the Treatise. Three are based on families in the Parathuramminacea, 1964, 2.9 million families in the Endothyracea, 1964. The Fusulinacea remains the same in both sources; the term "fusulinid" applies to any of the Fusulinida. The Fusulinida are fusulinids. However, the term "fusulinid" is applied just to the fusiform Fusulinacea and not to the entire order. Members of the Fusulinacea, are excellent index fossils for determining ages and correlating Upper Mississippian to Permian strata.
In some places fusulinaceans may be so abundant. List of prehistoric foraminifera genera
Tapinocephalus Assemblage Zone
The Tapinocephalus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the middle Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching 2,000 metres, occur from Merweville and Leeu-Gamka in its southernmost exposures, from Sutherland through to Beaufort West where outcrops start to only be found in the south-east, north of Oudshoorn and Willowmore, reaching up to areas south of Graaff-Reinet, its northernmost exposures occur around the towns Victoria West. The Tapinocephalus Assemblage Zone is the second biozone of the Beaufort Group; the name of the biozone refers to Tapinocephalus atherstonei, a large herbivorous tapinocephalid dinocephalian therapsid. It is characterised by the presence of this dinocephalian species along with the appearance of other advanced tapinocephalid dinocephalians, the large pareiasaur Bradysaurus baini.
It is the first biozone of the series where the dicynodont, Diictodon feliceps, species first appear. The first fossils to be found in the Beaufort Group rocks that encompass the current eight biozones were discovered by Andrew Geddes Bain in 1856. However, it was not until 1892 that it was observed that the geological strata of the Beaufort Group could be differentiated based on their fossil taxa; the initial undertaking was done by Harry Govier Seeley who subdivided the Beaufort Group into three biozones, which he named: Zone of "Pareiasaurians" Zone of "Dicynodonts" Zone of "highly specialized group of theriodonts"These proposed biozones Seeley named were subdivided further by Robert Broom between 1906 and 1909. Broom proposed the following biozones: Pareiasaurus beds Endothiodon beds Kistecephalus beds Lystrosaurus beds Procolophon beds Cynognathus bedsThe rocks of the current Tapinocephalus Assemblage Zone were first included with those of the lower Eodicynodon Assemblage Zone under the name "Pareiasaurus beds" by Broom.
Years Lieuwe Dirk Boonstra redefined the boundaries of the Tapinocephalus Assemblage Zone. As a young man Boonstra collaborated with Broom on research of dinocephalians. After embarking on further study of dinocephalian fossils and their biostratigraphy, Boonstra defined the lower and upper sections of this biozone. In the 1970s, Keyser and Smith proposed the renaming of the biozone to Dinocephalian Assemblage Zone. In 1984 James Kitching proposed to name the biozone after Tapinocephalus, accepted over Keyser and Smith’s proposal. However, the zoning of the biozone rocks remains as they were defined by Smith; the Tapinocephalus Assemblage Zone correlates with the Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group. Outcrops of this biozone are known from the south-western and central margins of the Abrahamskraal Formation where it conformably overlies the Eodicynodon Assemblage Zone in its south-western localities. In its northern and eastern localities it inter-fingers with Ecca Group-aged deposits.
This biozone is considered to be Middle Permian in age. The rocks of the Tapinocephalus Assemblage Zone consist of maroon to greyish red or purple mudstone layers which exhibit blocky weathering at exposed outcrops; the mudstones contain calcareous nodules and sheet limestones, both are indicative of a warm and seasonally arid climate, revealing the presence of paleocalcretes and carbonate precipitation in playa lakes. Paleosols are commonly found in the mudstones, which indicates a lack of deposition for long periods of time. In some deposits the mudstone layers contain thin chert lenses which have been attributed to silicified tuff deposits. Alternating beds of light grey to dark greenish grey siltstone and greenish grey to light olive grey sandstones which weather to light orange grey; the siltstones contain both symmetrical and asymmetrical ripple surfaces which indicate that paleocurrents traveled downstream in a northerly direction. Desiccation cracks which are infilled by fine sandstone are found.
The sandstones are fine-grained and tabular, indicating that deposition of these sandstones was in a low-energy fluvial environment. The sandstones are capped in the upper sections of the biozone with mudstone clast conglomerates; the depositional environment of the Tapinocephalus Assemblage Zone was formed by sedimentary material being deposited in the Karoo Basin by vast, low-energy alluvial plains flowing northwards from a southerly source area in the rising Gondwanide mountains. The Gondwanides were the result of crustal uplift that had begun to take course due to subduction of the Palaeo-pacific plate beneath the Gondwanan Plate. Orogenic pulses from the growing Gondwanides mountain chain and associated subduction created accommodation space for sedimentation in the Karoo Basin where the deposits of the Tapinocephalus Assemblage zone, all other succeeding assemblage zone deposits, were deposited over millions of years; the Tapinocephalus Assemblage Zone is characterized by the presence of Tapinocephalus atherstonei and Bradysaurus baini.
Vertebrate fossils found in this biozone are not common, however are most discovered as articulated single specimens within or associated with the calcareous nodules in the mudstone layers. As the name for this biozone suggests, it is renowned by paleontologists for its diverse Dinocephalian fossil species where all members of this family – the Anteosauridae and Tapinocephalidae – are represented. Example species from these families are Anteosaurus magnificus, Jonkeria boonstrai, Tapinocephalus atherstonei respectively. Other notable dinoceph
Texas is the second largest state in the United States by both area and population. Geographically located in the South Central region of the country, Texas shares borders with the U. S. states of Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the west, the Mexican states of Chihuahua, Nuevo León, Tamaulipas to the southwest, while the Gulf of Mexico is to the southeast. Houston is the most populous city in Texas and the fourth largest in the U. S. while San Antonio is the second-most populous in the state and seventh largest in the U. S. Dallas–Fort Worth and Greater Houston are the fourth and fifth largest metropolitan statistical areas in the country, respectively. Other major cities include Austin, the second-most populous state capital in the U. S. and El Paso. Texas is nicknamed "The Lone Star State" to signify its former status as an independent republic, as a reminder of the state's struggle for independence from Mexico; the "Lone Star" can be found on the Texan state seal.
The origin of Texas's name is from the word taysha. Due to its size and geologic features such as the Balcones Fault, Texas contains diverse landscapes common to both the U. S. Southern and Southwestern regions. Although Texas is popularly associated with the U. S. southwestern deserts, less than 10% of Texas's land area is desert. Most of the population centers are in areas of former prairies, grasslands and the coastline. Traveling from east to west, one can observe terrain that ranges from coastal swamps and piney woods, to rolling plains and rugged hills, the desert and mountains of the Big Bend; the term "six flags over Texas" refers to several nations. Spain was the first European country to claim the area of Texas. France held a short-lived colony. Mexico controlled the territory until 1836 when Texas won its independence, becoming an independent Republic. In 1845, Texas joined the union as the 28th state; the state's annexation set off a chain of events that led to the Mexican–American War in 1846.
A slave state before the American Civil War, Texas declared its secession from the U. S. in early 1861, joined the Confederate States of America on March 2nd of the same year. After the Civil War and the restoration of its representation in the federal government, Texas entered a long period of economic stagnation. Four major industries shaped the Texas economy prior to World War II: cattle and bison, cotton and oil. Before and after the U. S. Civil War the cattle industry, which Texas came to dominate, was a major economic driver for the state, thus creating the traditional image of the Texas cowboy. In the 19th century cotton and lumber grew to be major industries as the cattle industry became less lucrative, it was though, the discovery of major petroleum deposits that initiated an economic boom which became the driving force behind the economy for much of the 20th century. With strong investments in universities, Texas developed a diversified economy and high tech industry in the mid-20th century.
As of 2015, it is second on the list of the most Fortune 500 companies with 54. With a growing base of industry, the state leads in many industries, including agriculture, energy and electronics, biomedical sciences. Texas has led the U. S. in state export revenue since 2002, has the second-highest gross state product. If Texas were a sovereign state, it would be the 10th largest economy in the world; the name Texas, based on the Caddo word táyshaʼ "friend", was applied, in the spelling Tejas or Texas, by the Spanish to the Caddo themselves the Hasinai Confederacy, the final -s representing the Spanish plural. The Mission San Francisco de los Tejas was completed near the Hasinai village of Nabedaches in May 1690, in what is now Houston County, East Texas. During Spanish colonial rule, in the 18th century, the area was known as Nuevo Reino de Filipinas "New Kingdom of the Philippines", or as provincia de los Tejas "province of the Tejas" also provincia de Texas, "province of Texas", it was incorporated as provincia de Texas into the Mexican Empire in 1821, declared a republic in 1836.
The Royal Spanish Academy recognizes both spellings and Texas, as Spanish-language forms of the name of the U. S. State of Texas; the English pronunciation with /ks/ is unetymological, based in the value of the letter x in historical Spanish orthography. Alternative etymologies of the name advanced in the late 19th century connected the Spanish teja "rooftile", the plural tejas being used to designate indigenous Pueblo settlements. A 1760s map by Jacques-Nicolas Bellin shows a village named Teijas on Trinity River, close to the site of modern Crockett. Texas is the second-largest U. S. state, with an area of 268,820 square miles. Though 10% larger than France and twice as large as Germany or Japan, it ranks only 27th worldwide amongst country subdivisions by size. If it were an independent country, Texas would be the 40th largest behind Zambia. Texas is in the south central part of the United States of America. Three of its borders are defined by rivers; the Rio Grande forms a natural border with the Mexican states of Chihuahua, Nuevo León, Tamaulipas to the south.
The Red River forms a natural border with Arkansas to the north. The Sabine River forms a natural border with Louisiana to the east; the Texas Panhandle has an eastern border with Oklahoma at 100° W, a northern border with Oklahoma at 36°30' N and a western
Jonkeria is an extinct genus of dinocephalians. Species were large and omnivorous, from the Tapinocephalus Assemblage Zone, Lower Beaufort Group, of the South African Karroo; the overall length was 3.5 metres or more, the skull about 55 cm long. The skull is nearly twice as long as wide, the snout is elongated and provided with sharp incisors and large canines; the cheek teeth were small. The body is robustly built, the limbs stout. According to Boonstra 1969 p. 38, Jonkeria cannot be distinguished from its relative Titanosuchus on cranial grounds, but only in limb length. About a dozen species have been named, including J. truculenta. At least some of the other species were synonymised by Boonstra 1969. There has been no recent review of the genus. List of synapsids Boonstra, L. D. 1969, "The Fauna of the Tapincephalus Zone," Ann. S. Afr. Mus. 56 1-73, pp. 35–38 Colbert, E. H. Evolution of the Vertebrates, John Wiley & Sons Inc von Zittel, K. A, Textbook of Paleontology, C. R. Eastman, 2nd edition, Macmillan & Co. vol.2, p. 255