The Triassic is a geologic period and system The geologic time scale is a chronologic schema relating stratigraphy to time that is used by geologists, paleontologists and other earth scientists to describe the timing and relationships between events that have occurred during the history of the Earth. The table of geologic time spans presented here agrees with the dates and nomenclature that extends from about 251 to 199 Ma Annum is one form of the Latin noun meaning year, not a form normally used for derivatives in modern languages: the accusative singular of the second declension masculine noun annus , anni (genitive singular and nominative plural) (million years ago). As the first period of the Mesozoic The Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino, in the 18th century, although his original name for the era now called the "Mesozoic" was "Secondary" . Lying between the Paleozoic and the Cenozoic, "Mesozoic" means "middle Era, the Triassic follows the Permian The Permian[note 1] is a geologic period and system characterized by widespread, diverse and maturing lifeforms which comes just after the Carboniferous and that extends from 299.0 ± 0.8 to 251.0 ± 0.4 Ma . It is the last period of the Paleozoic Era and famous for its ending epoch event, the largest mass extinction known to science. The Permian and is followed by the Jurassic The Jurassic is a geologic period and system that extends from about 199.6± 0.6 Ma to 145.5± 4 Ma, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the "Age of Reptiles". The start of the period is marked by the major Triassic–. Both the start and end of the Triassic are marked by major extinction events An extinction event is a sharp decrease in the number of species in a relatively short period of time. Mass extinctions affect most major taxonomic groups present at the time — birds, mammals, reptiles, amphibians, fish, invertebrates and other simpler life forms. They may be caused by one or both of:. The extinction event that closed the Triassic period has recently been more accurately dated, but as with most older geologic periods, the rock beds that define the start and end are well identified, but the exact dates of the start and end of the period are uncertain by a few million years.

During the Triassic, both marine and continental life show an adaptive radiation An adaptive radiation is a rapid evolutionary radiation characterized by an increase in the morphological and ecological diversity of a single, rapidly diversifying lineage. Phenotypes adapt in response to the environment, with new and useful traits arising. This is an evolutionary process driven by natural selection beginning from the starkly impoverished biosphere The biosphere is the global sum of all ecosystems. It can also be called the zone of life on Earth. From the broadest biophysiological point of view, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, hydrosphere, and atmosphere that followed the Permian-Triassic extinction The Permian–Triassic extinction event, informally known as the Great Dying, was an extinction event that occurred 251.4 million years ago, forming the boundary between the Permian and Triassic geologic periods. It was the Earth's most severe extinction event, with up to 96 percent of all marine species and 70 percent of terrestrial vertebrate. Corals of the hexacorallia Hexacorallia is a subclass of Anthozoa comprising ~4,300 species of water-based organisms formed of colonial polyps generally with 6-fold symmetry. This includes all of the stony corals, which are vital for coral reef formation, as well as all sea anemones, tube anemones, and zoanthids within six extant orders. They are distinguished from the group made their first appearance. The first flying vertebrates, the pterosaurs Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period (220 to 65.5 million years ago). Pterosaurs are the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the legs, evolved during the Triassic.

Dating and subdivisions

The Triassic was named in 1834 by Friedrich Von Alberti Dr. Friedrich August von Alberti was a German geologist whose ground-breaking 1834 publication recognized the unity of the three characteristic strata that compose the sedimentary deposits of the Triassic period in Northern Europe (Latin trias meaning triad). From the fossils contained in the three distinct layers— of red bed sandstones, capped from the three distinct layers (Latin trias meaning triad)—red beds The term red beds usually refers to strata of reddish-colored sedimentary rocks such as sandstone, siltstone or shale that were deposited in hot climates under oxidizing conditions. The red color comes from iron oxide in their mineral structure. Although they have been deposited throughout the Phanerozoic, they are most commonly associated with, capped by chalk Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. It forms under relatively deep marine conditions from the gradual accumulation of minute calcite plates (coccoliths) shed from micro-organisms called coccolithophores. It is common to find flint and chert nodules embedded in chalk. Chalk can also, followed by black shales Shale is a fine-grained sedimentary rock whose original constituents were clay minerals or muds. It is characterized by thin laminae breaking with an irregular curving fracture, often splintery and usually parallel to the often-indistinguishable bedding plane. This property is called fissility. Non-fissile rocks of similar composition but made of—that are found throughout Germany Germany (pronounced /ˈdʒɜrməni/ ), officially the Federal Republic of Germany (German: Bundesrepublik Deutschland, pronounced [ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant] ( listen)), is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south and northwest Europe Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, and by the Caucasus Mountains to the southeast. Europe is washed upon to the north by the Arctic Ocean and, called the 'Trias'.

The Triassic is usually separated into Early, Middle, and Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age. The Late Triassic spans the time between 228.0 ± 2 Ma and 1 Epochs Series are subdivisions of rock layers made based on the age of the rock and coresponding to the dating system unit called an epoch, both being formally defined international conventions of the geological timescale. A series is therefore a sequence of rock depositions defining a chronostratigraphic unit. Series are subdivisions of systems and are, and the corresponding rocks are referred to as Lower, Middle, or Upper Triassic. The faunal stages In chronostratigraphy, a stage is a succession of rock strata laid down in an single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries from the youngest to oldest are:

Paleogeography

During the Triassic, almost all the Earth's land mass was concentrated into a single supercontinent In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today centered more or less on the equator, called Pangaea The name was first used by the German originator of the continental drift theory, Alfred Wegener, in the 1920 edition of his book The Origin of Continents and Oceans , in which a postulated supercontinent Pangaea played a key role ("all the land"). From the east a vast gulf entered Pangaea, the Tethys sea The Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean. It opened farther westward in the mid-Triassic, at the expense of the shrinking Paleo-Tethys Ocean, an ocean that existed during the Paleozoic The Paleozoic or Palaeozoic Era (from the Greek palaios , "old" and zoe (ζωή), "life", meaning "ancient life") is the earliest of three geologic eras of the Phanerozoic eon. The Paleozoic spanned from roughly 542 to 251 million years ago (ICS, 2004), and is subdivided into six geologic periods; from oldest to. The remaining shores were surrounded by the world-ocean known as Panthalassa ("all the sea"). All the deep-ocean sediments laid down during the Triassic have disappeared through subduction In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. A subduction zone is an area on Earth where two tectonic plates move towards one another and subduction occurs. Rates of subduction are typically of oceanic plates; thus, very little is known of the Triassic open ocean. The supercontinent Pangaea was rifting during the Triassic—especially late in the period—but had not yet separated. The first nonmarine sediments in the rift Typical rift features are a central linear downdropped fault segment, called a graben, with parallel normal faulting and rift-flank uplifts on either side forming a rift valley, where the rift remains above sea level. The axis of the rift area commonly contains volcanic rocks and active volcanism is a part of many, but not all active rift systems that marks the initial break-up of Pangea—which separated New Jersey New Jersey ( /nuːˈdʒɝːzi/ ) is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north by New York, and to the east, the Hudson River, Sandy Hook Bay, Long Island and the Atlantic Ocean. Delaware borders New Jersey only on the southwestern side, and Pennsylvania lies to the west of New Jersey from Morocco Morocco , officially the Kingdom of Morocco (Arabic: المملكة المغربية‎), is a country located in North Africa with a population of nearly 32 million and an area just under 447,000 square kilometres (173,000 sq mi). Its capital is Rabat, and its largest city is Casablanca. Morocco has a coast on the Atlantic Ocean that reaches past—are of Late Triassic age; in the U.S., these thick sediments comprise the Newark Group.^[7] Because of the limited shoreline of one super-continental mass, Triassic marine deposits are globally relatively rare, despite their prominence in Western Europe Western Europe refers to the countries generally in the westernmost half of Europe, but the definition is complex and carries political connotations. As a result, geographically eastern countries that steered clear of Soviet influence during the Cold War are usually included, while Western members of the former Eastern Bloc (Czech Republic, Poland), where the Triassic was first studied. In North America North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific Ocean; South America lies to the, for example, marine deposits are limited to a few exposures in the west. Thus Triassic stratigraphy Stratigraphy, a branch of geology, studies rock layers and layering . It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy includes two related subfields: lithologic or lithostratigraphy and biologic stratigraphy or biostratigraphy is mostly based on organisms living in lagoons and hypersaline environments, such as Estheria crustaceans.

Africa

At the beginning of the Mesozoic Era, Africa was joined with Earth's other continents in Pangaea.^[8] Africa shared the supercontinent's relatively uniform fauna which was dominated by theropods, prosauropods and primitive ornithischians by the close of the Triassic period.^[8] Late Triassic fossils are found through-out Africa, but are more common in the south than north.^[8] The boundry separating the Triassic and Jurassic marks the advent of an extinction event with global impact, although African strata from this time period have not been thoroughly studied.^[8]

Climate

The Triassic climate was generally hot and dry, forming typical red bed sandstones Sandstone is a sedimentary rock composed mainly of sand-size mineral or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, gray and white. Since sandstone beds often form and evaporites Evaporites are water-soluble mineral sediments that result from the evaporation of bodies of surficial water. Evaporites are considered sedimentary rocks. There is no evidence of glaciation A glacier is a large mass of ice moving slowly over some land surface or down a valley, formed over long periods from the accumulation of snow in areas where the amount of snow that falls exceeds the amount that melts. The word glacier comes from French via the Vulgar Latin glacia, and ultimately from Latin glacies meaning ice at or near either pole; in fact, the polar regions were apparently moist and temperate In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally mild, rather than extreme hot or cold. But in continental areas, such as central North America the variations between summer and winter can be extreme. In regions traditionally, a climate suitable for reptile-like creatures. Pangaea's large size limited the moderating effect of the global ocean; its continental climate Continental climate is a climate that is characterized by winter temperatures cold enough to support a fixed period of snow cover each year, and relatively moderate precipitation occurring mostly in summer, although east coast areas may show an even distribution of precipitation. Regions containing a continental climate exist in portions of the was highly seasonal, with very hot summers and cold winters.^[9] It probably had strong, cross A cross is a geometrical figure consisting of two lines or bars perpendicular to each other, dividing one or two of the lines in half. The lines usually run vertically and horizontally; if they run diagonally, the design is technically termed a saltire-equatorial monsoons.^[9]

Life

Three categories of organisms can be distinguished in the Triassic record: holdovers from the Permian-Triassic extinction, new groups which flourished briefly, and other new groups which went on to dominate the Mesozoic world.

In marine environments, new modern types of corals appeared in the Early Triassic, forming small patches of reefs of modest extent compared to the great reef systems of Devonian times or modern reefs. The shelled cephalopods called ammonites recovered, diversifying from a single line that survived the Permian extinction. The fish fauna was remarkably uniform, reflecting the fact that very few families survived the Permian extinction. There were also many types of marine reptiles. These included the Sauropterygia, which featured pachypleurosaurs and nothosaurs (both common during the Middle Triassic, especially in the Tethys region), placodonts, and the first plesiosaurs; the first of the lizardlike Thalattosauria (askeptosaurs); and the highly successful ichthyosaurs, which appeared in Early Triassic seas and soon diversified, some eventually developing to huge size during the late Triassic.

On land, the holdover plants included the lycophytes, the dominant cycads, ginkgophyta (represented in modern times by Ginkgo biloba) and glossopterids. The spermatophytes, or seed plants came to dominate the terrestrial flora: in the northern hemisphere, conifers flourished. Glossopteris (a seed fern) was the dominant southern hemisphere tree during the Early Triassic period.

Temnospondyl amphibians were among those groups that survived the Permian-Triassic extinction, some lineages (e.g. Trematosaurs) flourishing briefly in the Early Triassic, while others (e.g. capitosaurs) remained successful throughout the whole period, or only came to prominence in the Late Triassic (e.g. plagiosaurs, metoposaurs). As for other amphibians, the first Lissamphibia are known from the Early Triassic, but the group as a whole did not become common until the Jurassic, when the temnospondyls had become very rare.

Archosauromorph reptiles — especially archosaurs — progressively replaced the synapsids that had dominated the Permian. Although Cynognathus was a characteristic top predator in earlier Triassic (Olenekian and Anisian) Gondwana, and both kannemeyeriid dicynodonts and gomphodont cynodonts remained important herbivores during much of the period. By the end of the Triassic, synapsids played only bit parts. During the Carnian (early part of the Late Triassic), some advanced cynodont gave rise to the first mammals. At the same time the Ornithodira, which until then had been small and insignificant, evolved into pterosaurs and a variety of dinosaurs. The Crurotarsi were the other important archosaur clade, and during the Late Triassic these also reached the height of their diversity, with various groups including the phytosaurs, aetosaurs, several distinct lineages of Rauisuchia, and the first crocodylians (the Sphenosuchia). Meanwhile the stocky herbivorous rhynchosaurs and the small to medium-sized insectivorous or piscivorous Prolacertiformes were important basal archosauromorph groups throughout most of the Triassic.

Among other reptiles, the earliest turtles, like Proganochelys and Proterochersis, appeared during the Norian (middle of the Late Triassic). The Lepidosauromorpha—specifically the Sphenodontia—are first known in the fossil record a little earlier (during the Carnian). The Procolophonidae were an important group of small lizard-like herbivores.

Archosaurs were initially rarer than the therapsids which had dominated Permian terrestrial ecosystems, but they began to displace therapsids in the mid-Triassic.^[10] This "Triassic Takeover" may have contributed to the evolution of mammals by forcing the surviving therapsids and their mammaliform successors to live as small, mainly nocturnal insectivores; nocturnal life probably forced at least the mammaliforms to develop fur and higher metabolic rates.^[11]

Coal

At the start of the Triassic period coal is noticeable by its absence throughout the world. This is known as the "coal gap" and can be seen as part of the Permian–Triassic extinction event.^[5] Sharp drops in sea level across the Permo Triassic boundary may be partially to blame.^[12] During the preceding Permian period the hot desert conditions had contributed to the evaporation of many inland seas and the inundation of these seas, perhaps by a number of tsunami events may have been responsible for the drop in sea level.^[13] There are large salt basins in the southwest United States and a very large basin is suspected in central Canada.^[14]

Immediately above the boundary the glossopteris flora was suddenly^[15] largely displaced by an Australia wide coniferous flora containing few species and containing a lycopod herbaceous under story. Conifers became common in Eurasia also. Each of these groups of conifers arose from endemic species because conifers are very poor at crossing ocean barriers and they remained separated for hundreds of millions of years, largely to the present. Podocarpis was south and Pines, Junipers, and Sequoias were north, for instance. The dividing line ran through the Amazon Valley, across the Sahara, and north of Arabia, India, Thailand, and Australia.^[16][17] It has been suggested that there was a climate barrier for the conifers.^[18] although water barriers are more plausible. If so, something that can cross at least short water barriers must have been involved in producing the coal hiatus. Hot climate could have been an important auxiliary factor across Antarctica or the Bering Straights, however. There was a spike of fern and lycopod spores immediately after the close of the Permian.^[19] In addition there was also a spike of fungal spores immediately after the Permian-Triassic boundary.^[20] This spike may have lasted 50,000 years in Italy and 200,000 years in China and must have contributed to the climate warmth.

If so, something besides an instant catastrophe must have been involved to cause the coal hiatus because fungi would surely have removed all dead vegetation and coal forming detritus in a few decades in most tropical places. Besides, the fungal spores rose gradually and declined similarly. There was also much woody debris. Each phenomenon would hint at widespread vegetative death. Whatever caused the coal hiatus must have started in North America 25 million years sooner.^[21].

Lagerstätten

The Monte San Giorgio lagerstätte, now in the Lake Lugano region of northern Italy and Switzerland, was in Triassic times a lagoon behind reefs with an anoxic bottom layer, so there were no scavengers and little turbulence to disturb fossilization, a situation that can be compared to the better-known Jurassic Solnhofen limestone lagerstätte. The remains of fish and various marine reptiles (including the common pachypleurosaur Neusticosaurus, and the bizarre long-necked archosauromorph Tanystropheus), along with some terrestrial forms like Ticinosuchus and Macrocnemus, have been recovered from this locality. All these fossils date from the Anisian/Ladinian transition (about 237 million years ago).

Late Triassic extinction event

The Triassic period ended with a mass extinction, which was particularly severe in the oceans; the conodonts disappeared, and all the marine reptiles except ichthyosaurs and plesiosaurs. Invertebrates like brachiopods, gastropods, and molluscs were severely affected. In the oceans, 22% of marine families and possibly about half of marine genera went missing according to University of Chicago paleontologist Jack Sepkoski.

Though the end-Triassic extinction event was not equally devastating everywhere in terrestrial ecosystems, several important clades of crurotarsans (large archosaurian reptiles previously grouped together as the thecodonts) disappeared, as did most of the large labyrinthodont amphibians, groups of small reptiles, and some synapsids (except for the proto-mammals). Some of the early, primitive dinosaurs also went extinct, but other more adaptive dinosaurs survived to evolve in the Jurassic. Surviving plants that went on to dominate the Mesozoic world included modern conifers and cycadeoids.

What caused this Late Triassic extinction is not known with certainty. It was accompanied by huge volcanic eruptions that occurred as the supercontinent Pangaea began to break apart about 202 to 191 million years ago [(40Ar/39Ar dates^[22])], forming the Central Atlantic Magmatic Province [(CAMP)],^[23] one of the largest known inland volcanic events since the planet cooled and stabilized. Other possible but less likely causes for the extinction events include global cooling or even a bolide impact, for which an impact crater containing Manicouagan Reservoir in Quebec, Canada, has been singled out. At the Manicouagan impact crater, however, recent research has shown that the impact melt within the crater has an age of 214±1 Ma. The date of the Triassic-Jurassic boundary has also been more accurately fixed recently, at 201.58±0.28 Ma. Both dates are gaining accuracy by using more accurate forms of radiometric dating, in particular the decay of uranium to lead in zircons formed at the impact. So the evidence suggests the Manicouagan impact preceded the end of the Triassic by approximately 10±2 Ma. Therefore it could not be the immediate cause of the observed mass extinction.^[24]

The number of Late Triassic extinctions is disputed. Some studies suggest that there are at least two periods of extinction towards the end of the Triassic, between 12 and 17 million years apart. But arguing against this is a recent study of North American faunas. In the Petrified Forest of northeast Arizona there is a unique sequence of latest Carnian-early Norian terrestrial sediments. An analysis in 2002 found no significant change in the paleoenvironment.^[25] Phytosaurs, the most common fossils there, experienced a change-over only at the genus level, and the number of species remained the same. Some aetosaurs, the next most common tetrapods, and early dinosaurs, passed through unchanged. However, both phytosaurs and aetosaurs were among the groups of archosaur reptiles completely wiped out by the end-Triassic extinction event.

It seems likely then that there was some sort of end-Carnian extinction, when several herbivorous archosauromorph groups died out, while the large herbivorous therapsids— the kannemeyeriid dicynodonts and the traversodont cynodonts— were much reduced in the northern half of Pangaea (Laurasia).

These extinctions within the Triassic and at its end allowed the dinosaurs to expand into many niches that had become unoccupied. Dinosaurs became increasingly dominant, abundant and diverse, and remained that way for the next 150 million years. The true "Age of Dinosaurs" is the Jurassic and Cretaceous, rather than the Triassic.

See also

• Geologic time scale
• List of fossil sites (with link directory)
• Paleorrota (Triassic place in Brazil)

Notes

1. ^ Image:Sauerstoffgehalt-1000mj.svg
2. ^ Image:Phanerozoic Carbon Dioxide.png
3. ^ Image:All palaeotemps.png
4. ^ McElwain, J.C.; Punyasena, S.W. (2007). "Mass extinction events and the plant fossil record". Trends in Ecology & Evolution 22 (10): 548-557. doi:10.1016/j.tree.2007.09.003.
5. ^ ^{a b} Retallack GJ Veevers JJ & Morante R (1996). "Global coal gap between Permian–Triassic extinctions and middle Triassic recovery of peat forming plants". GSA Bulletin 108 (2): 195–207. http://bulletin.geoscienceworld.org/cgi/content/abstract/108/2/195. Retrieved on 2007-09-29.
6. ^ Payne, J.L.; Lehrmann, D.J.; Wei, J.; Orchard, M.J.; Schrag, D.P.; Knoll, A.H. (2004). "Large Perturbations of the Carbon Cycle During Recovery from the End-Permian Extinction". Science 305 (5683): 506. doi:10.1126/science.1097023. http://www.sciencemag.org/cgi/content/abstract/305/5683/506.
7. ^ Lecture 10 - Triassic: Newark, Chinle
8. ^ ^{a b c d} Jacobs, Louis, L. (1997). "African Dinosaurs." Encyclopedia of Dinosaurs. Edited by Phillip J. Currie and Kevin Padian. Academic Press. p. 2-4.
9. ^ ^{a b} Stanley, 452-3.
10. ^ Tanner LH, Lucas SG & Chapman MG (2004). "Assessing the record and causes of Late Triassic extinctions" (PDF). Earth-Science Reviews 65 (1-2): 103-139. doi:10.1016/S0012-8252(03)00082-5. http://nmnaturalhistory.org/pdf_files/TJB.pdf. Retrieved on 2007-10-22.
11. ^ Ruben, J.A., and Jones, T.D. (2000). "Selective Factors Associated with the Origin of Fur and Feathers". American Zoologist 40 (4): 585–596. doi:10.1093/icb/40.4.585. http://icb.oxfordjournals.org/cgi/content/full/40/4/585.
12. ^ Holser WT Schonlaub H_P,Moses AJr Boekelmann K Klein P Magaritz MOrth CJ Fenninger A Jenny C Kralik M Mauritsch EP Schramm J_M Sattagger K Schmoller R 1989 A unique geochemical record at the Permian/Triassic boundary. Nature 337; 39, on p42
13. ^ Knauth LP 1998 Salinity history of the earth's early ocean, Nature 395; 554-555.
14. ^ Dott, R.H. and Batten, R.L. (1971) Evolution of the Earth, 4th ed. McGraw Hill, NY.
15. ^ Hosher WT Magaritz M Clark D 1987 Events near the Permian-Triassic boundary. Mod. Geol. 11; 155-180, on p173-174.
16. ^ Florin R (1963) The distribution of Conifer and Taxad genera in time and space. Acta Horti Bergiani. 20, 121-312.
17. ^ Melville R (1966) Continental drift, Mesozoic continents, and the migrations of the angiosperms. Nature 211, 116.
18. ^ Darlington PJ, (1965) Biogeography of the southern end of the world. Harvard University Press, Cambridge Mass., on p168.
19. ^ Retallack GJ (1995) Permian -Triassic life crises on land. Science 267, 77-79.
20. ^ Eshet Y Rampino MR (1995) Fungal event and palynological record of ecological crises and recovery across Permian-Triassic boundary. Geology 23, 967-970, on p969.
21. ^ Retallack GJ Veevers JJ Morante R (1996) Global coal gap between Permian-Triassic extinctions and middle Triassic recovery of peat forming plants (review). Geological Society Am. Bull. 108, 195-207.
22. ^ Nomade et al.,2007 Palaeogeography, Palaeoclimatology, Palaeoecology 244, 326-344.
23. ^ Marzoli et al., 1999, Science 284. Extensive 200-million-year-old continental flood basalts of the Central Atlantic Magmatic Province, pp. 618-620.
24. ^ Hodych & Dunning, 1992.
25. ^ No Significant Nonmarine Carnian-Norian (Late Triassic) Extinction Event: Evidence From Petrified Forest National Park

References

• Emiliani, Cesare. (1992). Planet Earth: Cosmology, Geology, & the Evolution of Life & the Environment. Cambridge University Press. (Paperback Edition ISBN 0-521-40949-7)
• Ogg, Jim; June, 2004, Overview of Global Boundary Stratotype Sections and Points (GSSP's) [1] Accessed April 30, 2006
• Stanley, Steven M. Earth System History. New York: W.H. Freeman and Company, 1999. ISBN 0-7167-2882-6
• van Andel, Tjeerd, (1985) 1994, New Views on an Old Planet: A History of Global Change, Cambridge University Press

External links

• Overall introduction
• 'The Triassic world'
• Douglas Henderson's illustrations of Triassic animals
• Paleofiles page on the Triassic extinctions
• Examples of Triassic Fossils

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