The early Permian Crinoid Hypermorphocrinus magnospinosus from Cisuralia
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Crinoid
Chinese geologists have correctly interpreted the sequence in south China as including the youngest known marine Permian (Changxingian Stage), followed by earliest Triassic, strata with Otoceras (Griesbachian Stage, Gangetian Substage). Most of the Changxingian ammonoids are known only from China but one recently described species, Shizoloboceras fusuiense, is evidently congeneric with Paratirolites vediensis, which characterizes latest Permian (Dorashamian) beds of the south U.S.S.R. and Iran. This indicates that the youngest Permian beds of Iran and China are correlative. Alternative correlations which have been suggested, namely with Changxingian including beds younger than Dorashamian, and Gangetian correlative with Dorashamian, are rejected. Below the Changxingian is the Lopingian (or Wuchiapingan), characterized by a variety of early otocerataceans. Lopingian is more or less correlative with Dzhulfian.South China is the only known place where ammonoids of Dzhulfian (= Lopingian), Dorashamian (= Changxingian), and Gangetian (lowermost Triassic) ammonoids occur in a formational sequence. It does not necessarily follow that the Changxingian–Gangetian interval was one of faunal continuity and continuous deposition. Paleozoic-type brachiopods that locally occur in the basal metre of the Triassic formations do not establish that the relationship between the Permian and Triassic formations is transitional. The boundary between these formations is distinct. Probably, these brachiopods are derived from the subjacent Permian strata and are not natural members of the Triassic fauna.
Early Triassic
Conodont
Sequence (biology)
Correlative
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Abstract In New Zealand the stratigraphic contact between Triassic and Permian is generally unconformable, and there is no faunal intergradation. Griesbachian and Dienerian (basal Triassic) faunas are not known. The Permian segment is unusually thick, almost entirely marine, and moderately fossiliferous. The penultimate faunas, characteristic of the Waiitian Stage, are normal Permian faunas, approximately equivalent to the middle Dzhulfian zones of Armenia and Iran, Japan (Gujo), upper Ferntree Group of Tasmania, and upper Bellerophonkalk of Italy and Austria. Younger faunas, equivalent to the so-called Eotriassic of Armenia and Iran, are not present, though marine rocks are found. The topmost Permian fauna, characteristic of the Makarewan Stage of New Zealand, unlike the preceding faunas, lacks any of the major brachiopod groups, such as Stropho-menida or Productida which virtually disappeared at the end of the Paleozoic era. The brachiopod genera are members of orders and families which survived into the Triassic, such as Rhynchonellida, Spiriferacea and Dielasmatidae, but the genera are characteristic of the Permian Period. It is thus possible that the Makarewan Stage represents the very latest Permian, and the most convincing transition yet known into Triassic. The earliest Triassic in New Zealand contains poorly-dated bivalves. The earliest ammonoids are of middle Scythian, or Smithian age. The contact between Permian and Triassic in New Caledonia is less well exposed, and falls somewhere between brachiopods and bivalves of Capitanian (= basal Tatarian) age, equivalent to the Puruhauan Stage of New Zealand and Ladinian brachiopods. Ammonoids, including Xenodiscids, have been described by Avias and Guerin (1958) as either Late Permian or Early Triassic. Some are ascribed to Xenaspis of Middle Permian (Wargal-Chhidru age) but are accompanied by the Scythian genus Meekoceras. Mid-Permian Cyclolobus has also been identified. The sequence of Permian faunas in New Zealand provide a key to the nature of the Permian-Triassic contact. Three faunas in the sequence of eight are relatively impoverished generically, with strong affinities to faunas of eastern Australia, and coincide in age with the main glacial phases of the east Australian Permian. Overlying faunas are more diversified, and therefore, indicate relatively warmer water. Following faunas are very diverse and include Fusulinacea and reef-building corals, absent from the other faunal suites. Each warm-water fauna is followed by an abrupt faunal change to a cold-water fauna. This pattern of three cold episodes followed by warmer faunas is also reflected widely by faunas in the Northern Hemisphere through Canada and Siberia, and the cold episodes even affected paleotropical regions such as Texas, when cold-water genera such as Yakovlevia and Spiriferella were introduced for brief times. The pattern of glaciation and amelioration is also reflected in an intricate way by the nature of sedimentation over the entire globe, particularly in the formation of coral reefs, coal measures, tillites, salt deposits and red beds. Climatic changes provide a simple explanation of the great destruction of life at the end of the Permian Period. This is considered to have been real, affecting over 50 per cent of all life. Faunal analyses show that the genera and families which perished were essentially tropical in habitat, and that a prime cause lay in unusually high temperatures for a brief interval.
Early Triassic
Ladinian
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This paper gives a brief account of some interesting aspects of Permian stratigraphy in China as well as in other regions. Approval of an integrated chronostratigraphic scheme to replace the traditional standard succession in the Urals is significant. This scheme will not only serve as a working template for the Subcommission in defining the GSSPs for intra Systemic boundaries following the concept and procedures of modern stratigraphy, but also as a catalyst for developing a more reliable global correlation of the Permian. Increasing data of magnetostratigraphy, isotopic ages and sequencestratigraphy make it possible to erect a correlation between the proposed standard and other Permian successions. In China, as a consequence of implementing multi categories of stratigraphic classification, a Chinese chronostratigraphic scheme consisting of three series and 8 stages was established based on updated data on Permian cono donts, fusulinids, ammonoids and palynomorphs. The well established chronostratigraphic units such as the stratotypes of the Permian Triassic boundary, the Changhsingian Stage, and even the Lopingian Series were basically accepted as the global standard of the Upper Permian. The base of the Permian System in China, which has been traditionally placed at basal level of the Kungurian Stage for more than half a century, is now in agreement with the international standard. However, the proposed international and Chinese chronostratigraphic units need to be enhanced through defining the GSSP for its basal boundary, refining the standard stratigraphic sequences, subdivisions and inter regional correlation. And correlation of post Artinskian successions is far from precise because of the strong biogeographic differentiation.
Chronostratigraphy
Magnetostratigraphy
Stratotype
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An extremely diverse Permian crinoid fauna, one of the largest known from the Australian Palaeozoic, is described from the type section of the Callytharra Formation, west of Callytharra Springs, Western Australia. Forty species are recognized including 14 camerates, 25 inadunates, and 1 flexible. One new genus, Tapinocrinus, and three new species, T. macurdai, T. ingrami and Notiocatillocrinus callytharraensis are recorded. Recognition of Notiocatillocrinus and a dichocrinid in Western Australia establishes additional links with the eastern Australia Early Permian marine faunas. Eleven of the species are known to occur in the Permian of Timor. Recognition of these species suggests that the accepted age of the Callytharra Formation or, more likely, the Timor crinoid-bearing beds should be reconsidered.
Crinoid
Section (typography)
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The Permian System in the Jilong area,southern Tibet is subdivided into the Jilong and Quburiga formations,which are composed of a set of medium-thick beded limestones,quartzose sandstones,and mudstones.Abundant fossils were found in the Permian strata,including twenty three genera and forty species of brachiopods,seven genera and ten species of anthozoans,twelve genera and four species of bryozoans,one genera and two species of ammonoids,some crinoids,and inchnofossils.Five brachiopod assemblages,one ammonoid zone,two anthozoan assemblages,one crinoid horizon,and one ichnofossil horizon were established from the Permian System in the Jilong area.On the basis of lithostratigraphic and biostratigraphic data,the Jilong Formation is regarded as the deposits of Early Permian Artinskian-Sakmarian stage,and the Quburiga Formation can be correlated to the Chihsian-Maokouan stages,with the top Quburiga Formation belonging to the Middle-Late Permian Wuchiapingian Stage.
Crinoid
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Crinoid
Permian–Triassic extinction event
Extinction (optical mineralogy)
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A new microcrinoid, Pentececrinus parvus (sub-order Cyathocrinoidea), from the Louisiana formation (Devonian-Mississippian) of Missouri is described and compared with other nonbrachiate crinoids possessing only three circlets of plates (IBB, BB, OO) and an anal. Such crinoids have been reported from the Mississippian, Pennsylvanian, and Permian of the United States, the lower Carboniferous of Europe, and the Permian of Timor and Russia. With the addition of Pentececrinus, it is inferred that they form a phyletic group extending from late Devonian or early Mississippian to Permian time and that known Permian representatives do not indicate regressive evolution or aberrant specialization.
Devonian
Phyletic gradualism
Late Devonian extinction
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