Information about Jurassic Period
The Jurassic Period is a major unit of the geologic timescale that extends from about 199.6 ± 0.6 Ma (million years ago) to 145.4 ± 4.0 Ma, the end of the Triassic to 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.
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.
The Jurassic geological record is good in western Europe, where extensive marine sequences indicate a time when much of the continent was submerged under shallow tropical seas; famous locales include the Jurassic Coast World Heritage Site and the renowned late Jurassic lagerstätten of Holzmaden and Solnhofen.[2] In contrast, the North American Jurassic record is the poorest of the Mesozoic, with few outcrops at the surface.[3] Though the epicontinental Sundance Sea left marine deposits in parts of the northern plains of the United States and Canada during the late Jurassic, most exposed sediments from this period are continental, such as the alluvial deposits of the Morrison Formation.
The first of several massive batholiths were emplaced in the northern Cordillera beginning in the mid-Jurassic, marking the Nevadan orogeny.[4] Important Jurassic exposures are also found in Russia, India, South America, Japan, Australasia, and the United Kingdom.
In the invertebrate world, several new groups appeared, including rudists (a reef-forming variety of bivalves) and belemnites. The Jurassic also had diverse encrusting and boring (sclerobiont) communities (see Taylor & Wilson, 2003), and it saw a significant rise in the bioerosion of carbonate shells and hardgrounds. Especially common is the ichnogenus (trace fossil) Gastrochaenolites.
On land, large archosaurian reptiles remained dominant. The Jurassic was the golden age of the great sauropods—Camarasaurus, Diplodocus, Brachiosaurus, and many others—that roamed the land late in the period; their mainstays were either the prairies of ferns, palm-like cycads and bennettitales, or the higher coniferous growth, according to their adaptations. They were preyed upon by large theropods (Ceratosaurs, Megalosaurs, and Allosaurs). All these belong to the 'lizard hipped' or saurischian branch of the dinosaurs.
During the Late Jurassic, the first birds evolved from small coelurosaur dinosaurs. Ornithischian dinosaurs were less predominant than saurischian dinosaurs, although some like stegosaurs and small ornithopods played important roles as small and medium-to-large (but not sauropod-sized) herbivores. In the air, pterosaurs were common; they ruled the skies, filling many ecological roles now taken by birds.
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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.
| Mesozoic era | ||
|---|---|---|
| Triassic | Jurassic | Cretaceous |
Divisions
The Jurassic period of time is usually broken into Early, Middle, and Late subdivisions, also known as Lias, Dogger and Malm. The corresponding terms for the rocks are Lower, Middle, and Upper Jurassic. The faunal stages from youngest to oldest are:| Upper/Late Jurassic | |
| Tithonian | (150.8 ± 4.0 – 145.5 ± 4.0 Ma) |
| Kimmeridgian | (155.7 ± 4.0 – 150.8 ± 4.0 Ma) |
| Oxfordian | (161.2 ± 4.0 – 155.7 ± 4.0 Ma) |
| Middle Jurassic | |
| Callovian | (164.7 ± 4.0 – 161.2 ± 4.0 Ma) |
| Bathonian | (167.7 ± 3.5 – 164.7 ± 4.0 Ma) |
| Bajocian | (171.6 ± 3.0 – 167.7 ± 3.5 Ma) |
| Aalenian | (175.6 ± 2.0 – 171.6 ± 3.0 Ma) |
| Lower/Early Jurassic | |
| Toarcian | (183.0 ± 1.5 – 175.6 ± 2.0 Ma) |
| Pliensbachian | (189.6 ± 1.5 – 183.0 ± 1.5 Ma) |
| Sinemurian | (196.5 ± 1.0 – 189.6 ± 1.5 Ma) |
| Hettangian | (199.6 ± 0.6 – 196.5 ± 1.0 Ma) |
Paleogeography
During the early Jurassic, the supercontinent Pangaea broke up into the northern supercontinent Laurasia and the southern supercontinent Gondwana; the Gulf of Mexico opened in the new rift between North America and what is now Mexico's Yucatan Peninsula. The Jurassic North Atlantic Ocean was relatively narrow, while the South Atlantic did not open until the following Cretaceous Period, when Gondwana itself rifted apart.[1] The Tethys Sea closed, and the Neotethys basin appeared. Climates were warm, with no evidence of glaciation. As in the Triassic, there was apparently no land near either pole, and no extensive ice caps existed.The Jurassic geological record is good in western Europe, where extensive marine sequences indicate a time when much of the continent was submerged under shallow tropical seas; famous locales include the Jurassic Coast World Heritage Site and the renowned late Jurassic lagerstätten of Holzmaden and Solnhofen.[2] In contrast, the North American Jurassic record is the poorest of the Mesozoic, with few outcrops at the surface.[3] Though the epicontinental Sundance Sea left marine deposits in parts of the northern plains of the United States and Canada during the late Jurassic, most exposed sediments from this period are continental, such as the alluvial deposits of the Morrison Formation.
The first of several massive batholiths were emplaced in the northern Cordillera beginning in the mid-Jurassic, marking the Nevadan orogeny.[4] Important Jurassic exposures are also found in Russia, India, South America, Japan, Australasia, and the United Kingdom.
Fauna
Aquatic and marine
During the Jurassic, the primary vertebrates living in the seas were fish and marine reptiles. The latter include ichthyosaurs, plesiosaurs and marine crocodiles, of the families Teleosauridae and Metriorhynchidae.In the invertebrate world, several new groups appeared, including rudists (a reef-forming variety of bivalves) and belemnites. The Jurassic also had diverse encrusting and boring (sclerobiont) communities (see Taylor & Wilson, 2003), and it saw a significant rise in the bioerosion of carbonate shells and hardgrounds. Especially common is the ichnogenus (trace fossil) Gastrochaenolites.
Terrestrial
)
Large dinosaurs were dominant during the Jurassic Period.
During the Late Jurassic, the first birds evolved from small coelurosaur dinosaurs. Ornithischian dinosaurs were less predominant than saurischian dinosaurs, although some like stegosaurs and small ornithopods played important roles as small and medium-to-large (but not sauropod-sized) herbivores. In the air, pterosaurs were common; they ruled the skies, filling many ecological roles now taken by birds.
Flora
The arid, continental conditions characteristic of the Triassic steadily eased during the Jurassic period, especially at higher latitudes; the warm, humid climate allowed lush jungles to cover much of the landscape.[5] Conifers dominated the flora, as during the Triassic; they were the most diverse group and constituted the majority of large trees. Extant conifer families that flourished during the Jurassic included the Araucariaceae, Cephalotaxaceae, Pinaceae, Podocarpaceae, Taxaceae and Taxodiaceae.[6] The extinct Mesozoic conifer family Cheirolepidiaceae dominated low latitude vegetation, as did the shrubby Bennettitales.[7] Cycads were also common, as were ginkgos and tree ferns in the forest. Smaller ferns were probably the dominant undergrowth. Caytoniaceous seed ferns were another group of important plants during this time and are thought to have been shrub to small-tree sized.[8] Ginkgo-like plants were particularly common in the mid- to high northern latitudes. In the Southern Hemisphere, podocarps were especially successful, while Ginkgos and Czekanowskiales were rare.[9],[10]Notes:
1. ^ [1]
2. ^ [2]
3. ^ [3]]
4. ^ Monroe and Wicander, 607.
5. ^ Haines, 2000.
6. ^ Behrensmeyer et al, 1992, 349.
7. ^ Behrensmeyer et al., 1992, 352
8. ^ Behrensmeyer et al., 1992, 353
9. ^ Haines, 2000.
10. ^ Behrensmeyer et al., 1992, 352
2. ^ [2]
3. ^ [3]]
4. ^ Monroe and Wicander, 607.
5. ^ Haines, 2000.
6. ^ Behrensmeyer et al, 1992, 349.
7. ^ Behrensmeyer et al., 1992, 352
8. ^ Behrensmeyer et al., 1992, 353
9. ^ Haines, 2000.
10. ^ Behrensmeyer et al., 1992, 352
References
- Behrensmeyer, Anna K., Damuth, J.D., DiMichele, W.A., Potts, R., Sues, H.D. & Wing, S.L. (eds.) (1992), Terrestrial Ecosystems through Time: the Evolutionary Paleoecology of Terrestrial Plants and Animals, University of Chicago Press, Chicago and London, ISBN 0-226-04154-9 (cloth), ISBN 0-226-04155-7 (paper)
- Haines, Tim (2000) Walking with Dinosaurs: A Natural History, New York: Dorling Kindersley Publishing, Inc., p. 65. ISBN 0-563-38449-2
- Kazlev, M. Alan (2002) Paleos website Accessed Jan. 8, 2006
- Mader, Sylvia (2004) Biology, eighth edition
- Monroe, James S., and Reed Wicander. (1997) The Changing Earth: Exploring Geology and Evolution, 2nd ed. Belmont: West Publishing Company, 1997. ISBN 0-314-09577-2
- Ogg, Jim; June, 2004, Overview of Global Boundary Stratotype Sections and Points (GSSP's) http://www.stratigraphy.org/gssp.htm Accessed April 30, 2006.
- Taylor, P.D. and Wilson, M.A., 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews 62: 1-103. http://www.wooster.edu/geology/Taylor%26Wilson2003.pdf
External links
| Jurassic period | ||
|---|---|---|
| Lower/Early Jurassic | Middle Jurassic | Upper/Late Jurassic |
| Hettangian | Sinemurian Pliensbachian | Toarcian | Aalenian | Bajocian Bathonian | Callovian | Oxfordian | Kimmeridgian Tithonian |
A geologic period is a subdivision of geologic time that divides an era into smaller timeframes. The equivalent term used to demarcate rock layers and the fossil record is the system; thus the rocks of the Devonian System were laid down during the Devonian Period.
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The geological time scale is used by geologists and other scientists to describe the timing and relationships between events that have occurred during the history of Earth.
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Annum is a Latin noun meaning year. It is the accusative singular of the second declension masculine noun annus (nominative), anni (genitive) [1] .
As a unit of time, it is defined as exactly 365.
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As a unit of time, it is defined as exactly 365.
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The Triassic is a geologic period that extends from about 251 to 199 Ma (million years ago). As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events.
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The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i.e. from 145.5 ± 4.0 million years ago (Ma)) to the beginning of the Paleocene epoch of the Tertiary Period (about 65.5 ± 0.3 Ma).
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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' (making the modern era the 'Tertiary').
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Dinosauria *
Owen, 1842
Orders & Suborders
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Owen, 1842
Orders & Suborders
- Ornithischia
- Cerapoda
- Thyreophora
- Saurischia
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Triassic-Jurassic extinction event occurred 200 million years ago and is one of the major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans.
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For the Big Finish Productions audio play, see .
An extinction event (also known as: mass extinction; extinction-level event, ELE) is a sharp decrease in the number of species in a relatively short period of time...... Click the link for more information.
Alexandre Brongniart (1770 – 1847) was a French chemist, mineralogist, and zoologist, who collaborated with Georges Cuvier on a study of the geology of the region around Paris.
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Limestone is a sedimentary rock composed largely of the mineral calcite (calcium carbonate: CaCO3). Limestone often contains variable amounts of silica in the form of chert or flint, as well as varying amounts of clay, silt and sand as disseminations, nodules, or layers
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Jura Mountains is a small mountain range located north of the Alps, separating the Rhine and Rhone rivers and forming part of the watershed of each. The range is being continually deformed by mountain building, accommodating the compression from alpine folding as the main Alpine
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Anthem
"Das Lied der Deutschen" (third stanza)
also called "Einigkeit und Recht und Freiheit"
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"Das Lied der Deutschen" (third stanza)
also called "Einigkeit und Recht und Freiheit"
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Motto
Liberté, Égalité, Fraternité
"Liberty, Equality, Fraternity"
Anthem
"La Marseillaise"
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Liberté, Égalité, Fraternité
"Liberty, Equality, Fraternity"
Anthem
"La Marseillaise"
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Motto
Unus pro omnibus, omnes pro uno (Latin) (traditional)[1]
"One for all, all for one"
Anthem
"Swiss Psalm"
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Unus pro omnibus, omnes pro uno (Latin) (traditional)[1]
"One for all, all for one"
Anthem
"Swiss Psalm"
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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' (making the modern era the 'Tertiary').
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The Triassic is a geologic period that extends from about 251 to 199 Ma (million years ago). As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events.
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The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i.e. from 145.5 ± 4.0 million years ago (Ma)) to the beginning of the Paleocene epoch of the Tertiary Period (about 65.5 ± 0.3 Ma).
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Early Jurassic (in geology referred to as the Lower Jurassic, originally (and still in Europe) the "Lias") is the earliest of three epochs of the Jurassic period.
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The Middle Jurassic, called the Dogger in the European system of classification, is the second epoch of the Jurassic Period. It lasted from 180-154 million years ago.
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Paleogeograpgy
Pangaea began to separate into Laurasia and Gondwana and the Atlantic Ocean formed...... Click the link for more information.
Late Jurassic (or Malm) Epoch of the Jurassic Period is the unit of geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago, which is preserved in Upper Jurassic strata.
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Faunal stages are subdivisions of rock layers used primarily by paleontologists who study fossils rather than by geologists who study rock formations. Typically, a faunal stage will consist of a series of rocks that contain similar fossils.
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Late Jurassic (or Malm) Epoch of the Jurassic Period is the unit of geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago, which is preserved in Upper Jurassic strata.
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The Tithonian is the final stage of the Late Jurassic Epoch. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma (million years ago). It is followed by the Berriasian stage of the Early Cretaceous Epoch.
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Annum is a Latin noun meaning year. It is the accusative singular of the second declension masculine noun annus (nominative), anni (genitive) [1] .
As a unit of time, it is defined as exactly 365.
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As a unit of time, it is defined as exactly 365.
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The Kimmeridgian is a stage of the Late Jurassic Epoch. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma (million years ago).
The stage takes its name from the village of Kimmeridge on the Dorset coast, England where the exposure is at its greatest extent.
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The stage takes its name from the village of Kimmeridge on the Dorset coast, England where the exposure is at its greatest extent.
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The Oxfordian stage is the first stage of the Late Jurassic Epoch. It spans the time between 161.2 ± 4 Ma and 155.7 ± 4 Ma (million years ago).
The stage takes its name from the city of Oxford in England.
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The stage takes its name from the city of Oxford in England.
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The Middle Jurassic, called the Dogger in the European system of classification, is the second epoch of the Jurassic Period. It lasted from 180-154 million years ago.
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Paleogeograpgy
Pangaea began to separate into Laurasia and Gondwana and the Atlantic Ocean formed...... Click the link for more information.
The Callovian is a stage on the geologic time scale occurring 164.7 ± 4.0 Ma to 161.2 ± 4.0 Ma (million years ago). It is the last stage of the Middle Jurassic.
The stage takes its name from an old spelling of Kellaways Bridge, 3 km north-east of Chippenham in Wiltshire in
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The stage takes its name from an old spelling of Kellaways Bridge, 3 km north-east of Chippenham in Wiltshire in
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In the geologic timescale the Bathonian epoch is a stage during the Middle Jurassic, of the Mesozoic era of the Phanerozoic eon. It lasted from approximately 167.7 Ma to around 164.7 Ma (million years ago). The Bathonian age succeeds the Bajocian age and precedes the Callovian age.
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