The Jurassic period is a major unit of the geologic timescale that extends from about 200 million years Before Present at the end of the Triassic to 146 million years BP at the beginning of the Cretaceous. As with other geologic periods, the rock beds that define the start and end of the period are well identified, but the exact dates are uncertain by 5 - 10 million years. The Jurassic constitutes the middle period of the Mesozoic era, also known as the Age of Dinosaurs. The start of the period is marked by the major Triassic-Jurassic extinction event extinction event. The Jurassic was named by Alexandre Brogniart for the extensive marine limestone exposures of the Jura Mountains in the region where Germany, France and Switzerland meet. == Divisions == The Jurassic is usually broken into Lower Jurassic, Middle Jurassic, and Upper Jurassic (or Early, Middle and Late) subdivisions, also known as ''Lias'', ''Dogger'' and ''Malm''. The faunal stages from youngest to oldest are: {| | Upper Jurassic | |- | Tithonian | (150.8 ± 4.0 – 145.5 ± 4.0 MYA) |- | Kimmeridgean | (155.7 ± 4.0 – 150.8 ± 4.0 MYA) |- | Oxfordian stage | (161.2 ± 4.0 – 155.7 ± 4.0 MYA) |- | Middle Jurassic | |- | Callovian | (164.7 ± 4.0 – 161.2 ± 4.0 MYA) |- | Bathonian | (167.7 ± 3.5 – 164.7 ± 4.0 MYA) |- | Bajocian | (171.6 ± 3.0 – 167.7 ± 3.5 MYA) |- | Aalenian | (175.6 ± 2.0 – 171.6 ± 3.0 MYA) |- | Lower Jurassic | |- | Toarcian | (183.0 ± 1.5 – 175.6 ± 2.0 MYA) |- | Pliensbachian | (189.6 ± 1.5 – 183.0 ± 1.5 MYA) |- | Sinemurian | (196.5 ± 1.0 – 189.6 ± 1.5 MYA) |- | Hettangian | (199.6 ± 0.6 – 196.5 ± 1.0 MYA) |} == Paleogeography == During the early Jurassic, the supercontinent Pangea broke up into North America, Eurasia and Gondwana. Still, the early Atlantic Ocean and Tethys Ocean Oceans were relatively narrow. In the late Jurassic, the southern continent, Gondwana, started to break up. Climates were warm with no evidence of glacier. As in the Triassic, apparently there was no land near either pole, and no extensive ice caps existed. The geological record of the Jurassic is well exposed in western Europe, were marine sequences are found along the coasts. A shallow sea (epicontinental sea) was present in parts of the northern plains of the United States and Canada. Most Jurassic exposures in North America are continental. Important Jurassic exposures are also found in Russia, India, South America, Japan, Australasia, and the United Kingdom. == Animals and Plants == During the Jurassic, the "highest" life forms living in the seas were fish and marine reptiles. The latter include ichthyosaurs, plesiosaurs, and marine Crocodylia of the families Teleosauridae and Metriorhynchidae. In the invertebrate world, several new groups appeared, such as: * plankton foraminifera and calpionelids, which are of great Stratigraphy relevance; * rudists, a reef-forming variety of bivalvia; * belemnites; and * brachiopoda of the terebratulid and rinchonelid groups. Ammonite (shelled cephalopods) were particularly common and diverse, forming 62 different biozone. On land, large archosaurian reptiles remained dominant. Great plant-eating dinosaurs (sauropods) roamed the land, feeding on prairies of ferns and palm-like cycads and bennettitaleans. They were preyed upon by large theropods (Ceratosaurs, Megalosaurs, and Allosaurs). During the Malm the first Aves Evolution from small coelurosaur dinosaurs. All these belong to the "lizard hipped" or saurischian branch of the dinosaurs. In contrast, Ornithischian dinosaurs were less predominant, although some like stegosaurs and small ornithopods played important roles as small-medium- to large (but not sauropod large) herbivores. In the air, pterosaurs were common, filling many ecological roles now taken by Aves. == See Also == Though the movie ''Jurassic Park'' brought the word "Jurassic" to household usage, many of the creatures featured in that film would more likely be found in the Cretaceous period. ''For the hip hop group see Jurassic 5.'' Jurassic
Is there anyone who can make it so that all pages about a period in geological time have the same start and end dates mentioned on their articles as those mentioned on the article for the Gelologic Time scale?? User:66.32.113.158 21:22, 28 Mar 2004 (UTC)
Mesozoic
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Words begining with Jurassic:
Jurassic
Jurassic
Jurassic
Jurassic_5
Jurassic_5
Jurassic_Attack_(truck)
Jurassic_Coast
Jurassic_coast
Jurassic_craters
Jurassic_Five
Jurassic_Footer
Jurassic_Park
Jurassic_Park
Jurassic_Park
Jurassic_Park:Operation_Genesis
Jurassic_Park:_Operation_Genesis
Jurassic_Park_(computer_game)
Jurassic_Park_(movie)
Jurassic_Park_(NES_game)
Jurassic_Park_(SNES_game)
Jurassic_Park_(video_game)
Jurassic_Park_2
Jurassic_Park_3
Jurassic_Park_3_Island_Attack
Jurassic_Park_II
Jurassic_Park_III
Jurassic_Park_IV
Jurassic_Park_River_Adventure
Jurassic_Park_River_Adventure
Jurassic_Park_species
Jurassic_Period
Jurassic_period
Jurassic_Way
Jurassic
The Jurassic period is a major unit of the geologic timescale that extends from about 200 million years Before Present at the end of the Triassic to 146 million years BP at the beginning of the Cretaceous. As with other geologic periods, the rock beds that define the start and end of the period are well identified, but the exact dates are uncertain by 5 - 10 million years. The Jurassic constitutes the middle period of the Mesozoic era, also known as the Age of Dinosaurs. The start of the period is marked by the major Triassic-Jurassic extinction event extinction event. The Jurassic was named by Alexandre Brogniart for the extensive marine limestone exposures of the Jura Mountains in the region where Germany, France and Switzerland meet. == Divisions == The Jurassic is usually broken into Lower Jurassic, Middle Jurassic, and Upper Jurassic (or Early, Middle and Late) subdivisions, also known as ''Lias'', ''Dogger'' and ''Malm''. The faunal stages from youngest to oldest are: {| | Upper Jurassic | |- | Tithonian | (150.8 ± 4.0 – 145.5 ± 4.0 MYA) |- | Kimmeridgean | (155.7 ± 4.0 – 150.8 ± 4.0 MYA) |- | Oxfordian stage | (161.2 ± 4.0 – 155.7 ± 4.0 MYA) |- | Middle Jurassic | |- | Callovian | (164.7 ± 4.0 – 161.2 ± 4.0 MYA) |- | Bathonian | (167.7 ± 3.5 – 164.7 ± 4.0 MYA) |- | Bajocian | (171.6 ± 3.0 – 167.7 ± 3.5 MYA) |- | Aalenian | (175.6 ± 2.0 – 171.6 ± 3.0 MYA) |- | Lower Jurassic | |- | Toarcian | (183.0 ± 1.5 – 175.6 ± 2.0 MYA) |- | Pliensbachian | (189.6 ± 1.5 – 183.0 ± 1.5 MYA) |- | Sinemurian | (196.5 ± 1.0 – 189.6 ± 1.5 MYA) |- | Hettangian | (199.6 ± 0.6 – 196.5 ± 1.0 MYA) |} == Paleogeography == During the early Jurassic, the supercontinent Pangea broke up into North America, Eurasia and Gondwana. Still, the early Atlantic Ocean and Tethys Ocean Oceans were relatively narrow. In the late Jurassic, the southern continent, Gondwana, started to break up. Climates were warm with no evidence of glacier. As in the Triassic, apparently there was no land near either pole, and no extensive ice caps existed. The geological record of the Jurassic is well exposed in western Europe, were marine sequences are found along the coasts. A shallow sea (epicontinental sea) was present in parts of the northern plains of the United States and Canada. Most Jurassic exposures in North America are continental. Important Jurassic exposures are also found in Russia, India, South America, Japan, Australasia, and the United Kingdom. == Animals and Plants == During the Jurassic, the "highest" life forms living in the seas were fish and marine reptiles. The latter include ichthyosaurs, plesiosaurs, and marine Crocodylia of the families Teleosauridae and Metriorhynchidae. In the invertebrate world, several new groups appeared, such as: * plankton foraminifera and calpionelids, which are of great Stratigraphy relevance; * rudists, a reef-forming variety of bivalvia; * belemnites; and * brachiopoda of the terebratulid and rinchonelid groups. Ammonite (shelled cephalopods) were particularly common and diverse, forming 62 different biozone. On land, large archosaurian reptiles remained dominant. Great plant-eating dinosaurs (sauropods) roamed the land, feeding on prairies of ferns and palm-like cycads and bennettitaleans. They were preyed upon by large theropods (Ceratosaurs, Megalosaurs, and Allosaurs). During the Malm the first Aves Evolution from small coelurosaur dinosaurs. All these belong to the "lizard hipped" or saurischian branch of the dinosaurs. In contrast, Ornithischian dinosaurs were less predominant, although some like stegosaurs and small ornithopods played important roles as small-medium- to large (but not sauropod large) herbivores. In the air, pterosaurs were common, filling many ecological roles now taken by Aves. == See Also == Though the movie ''Jurassic Park'' brought the word "Jurassic" to household usage, many of the creatures featured in that film would more likely be found in the Cretaceous period. ''For the hip hop group see Jurassic 5.'' Jurassic
Jurassic
Is there anyone who can make it so that all pages about a period in geological time have the same start and end dates mentioned on their articles as those mentioned on the article for the Gelologic Time scale?? User:66.32.113.158 21:22, 28 Mar 2004 (UTC)
Jurassic
Mesozoic
See other meanings of words starting from letter:
J
JA | JB | JC | JD | JE | JF | JG | JH | JI | JK | JL | JM | JN | JO | JP | JR | JS | JT | JU | JW | JX | JY | JZ |Words begining with Jurassic:
Jurassic
Jurassic
Jurassic
Jurassic_5
Jurassic_5
Jurassic_Attack_(truck)
Jurassic_Coast
Jurassic_coast
Jurassic_craters
Jurassic_Five
Jurassic_Footer
Jurassic_Park
Jurassic_Park
Jurassic_Park
Jurassic_Park:Operation_Genesis
Jurassic_Park:_Operation_Genesis
Jurassic_Park_(computer_game)
Jurassic_Park_(movie)
Jurassic_Park_(NES_game)
Jurassic_Park_(SNES_game)
Jurassic_Park_(video_game)
Jurassic_Park_2
Jurassic_Park_3
Jurassic_Park_3_Island_Attack
Jurassic_Park_II
Jurassic_Park_III
Jurassic_Park_IV
Jurassic_Park_River_Adventure
Jurassic_Park_River_Adventure
Jurassic_Park_species
Jurassic_Period
Jurassic_period
Jurassic_Way
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