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The Late Jurassic is the third
epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by c ...
of the
Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic period million years ago (Mya) to the beginning of the Cretaceous period approximately Mya. The Jurassic constitutes the middle period of the ...
period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Period, a descriptor for a historical or period drama ...
, and it spans the
geologic time The geologic time scale (GTS) is a system of chronological dating that classifies geological strata (stratigraphy) in time. It is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships of events i ...
from 163.5 ± 1.0 to 145.0 ± 0.8
million years ago One million (1,000,000), or one thousand thousand, is the natural number following 999,999 and preceding 1,000,001. The word is derived from the early Italian ''millione'' (''milione'' in modern Italian), from ''mille'', "thousand", plus the augme ...
(Ma), which is preserved in Upper Jurassic
strata (Argentina). , Canada. These are Middle Cambrian marine sediments. This formation covers over half of Nova Scotia and is recorded as being 8,800 m (29,000 ft) thick in some areas. In geology and related fields, a stratum (plural: strata) is a l ...
.Owen 1987. In European
lithostratigraphy through Jurassic lithostratigraphy of the Colorado Plateau area of southeastern Utah that makes up much of the famous prominent rock formations in protected areas such as Capitol Reef National Park and Canyonlands National Park. From top to bottom ...
, the name "Malm" indicates rocks of Late Jurassic age. In the past, ''Malm'' was also used to indicate the unit of geological time, but this usage is now discouraged to make a clear distinction between lithostratigraphic and geochronologic/chronostratigraphic units.


Subdivisions

The Late Jurassic is divided into three ages, which correspond with the three (faunal) stages of Upper Jurassic rock:


Paleogeography

During the Late Jurassic epoch,
Pangaea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, and began to break apart about 175 million years ago. In ...

Pangaea
broke up into two
supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some earth scientists use a different definition, "a grouping of formerly dispersed continents", which ...
s,
Laurasia Laurasia (), a portmanteau for Laurentia and Asia, was the more northern of two large landmasses (the other being Gondwana) that formed part of the Pangaea supercontinent from around (Mya). It separated from Gondwana (beginning in the late Tria ...
to the north, and
Gondwana Gondwana () or Gondwanaland was a supercontinent that existed from the Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic (about 180 million years ago), with the opening of the Drake Passage, separating South ...
to the south. The result of this break-up was the spawning of the
Atlantic Ocean#REDIRECT Atlantic Ocean#REDIRECT Atlantic Ocean {{Redirect category shell, 1= {{R from other capitalisation ...
{{Redirect category shell, 1= {{R from other capitalisation ...

Atlantic Ocean
. However, at this time, the Atlantic Ocean was relatively narrow.


Life forms of the epoch

This epoch is well known for many famous types of
dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject ...
s, such as the
sauropod Sauropoda , whose members are known as sauropods (from ''sauro-'' + ''-pod'', "lizard-footed"), is a clade of saurischian ("lizard-hipped") dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their body), ...
s, the
theropod Theropoda ( from Greek 'wild beast' and 'foot'), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three-toed limbs. Theropods are generally classed as a group of saurischian dinosaurs. They we ...
s, the
thyreophora Thyreophora ("shield bearers", often known simply as "armored dinosaurs") is a group of armored ornithischian dinosaurs that lived from the early Jurassic Period until the end of the Cretaceous. Thyreophorans are characterized by the presence of ...
ns, and the
ornithopod Ornithopods () or members of the clade Ornithopoda ( or ) are a group of ornithischian dinosaurs that started out as small, bipedal running grazers, and grew in size and numbers until they became one of the most successful groups of herbivores in t ...
s. Other animals, such as
crocodile Crocodiles (subfamily Crocodylinae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. Crocodylinae, all of whose members are considered true crocodiles, is classifie ...
s and the first
bird Birds are a group of warm-blooded vertebrates constituting the class Aves , characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skele ...
s, appeared in the Jurassic. Listed here are only a few of the many Jurassic animals: :*''
Camarasaurus ''Camarasaurus'' ( ) was a genus of quadrupedal, herbivorous dinosaurs. It was the most common of the giant sauropods to be found in North America. Its fossil remains have been found in the Morrison Formation of Colorado and Utah, dating to the L ...
'', a large herbivorous sauropod dinosaur from North America :*''Apatosaurus'', a large herbivorous sauropod dinosaur from North America :*''Brachiosaurus'', a large herbivorous sauropod dinosaur from North America :*''Brontosaurus'', a large herbivorous sauropod dinosaur from North America :*''Diplodocus'', a large herbivorous sauropod dinosaur from North America :*''Barosaurus'', a large herbivorous sauropod dinosaur from North America :*''Europasaurus'', a small herbivorous sauropod dinosaur from Europe :*''Supersaurus'', possibly the largest North American sauropod of them all :*''Dicraeosaurus'', a large herbivorous sauropod dinosaur from Africa :*''Giraffatitan'', another large sauropod from Africa (usually recognized as a species of ''Brachiosaurus'') :*''Allosaurus'', possibly the biggest Jurassic predator, the most common Late Jurassic theropod of North America, also present in Europe :*''Epanterias'', one of the largest Jurassic carnivores, from North America (possibly just ''Allosaurus'') :*''Torvosaurus'', a large Jurassic carnivore, from North America and Europe :*''Ceratosaurus'', a medium-sized Jurassic carnivore of North America, Europe, and possibly Africa :*''Compsognathus'', a small theropod from Europe :*''Yangchuanosaurus'', a large theropod from Asia :*''Tuojiangosaurus'', a thyreophoran from Asia :*''Stegosaurus'', a thyreophoran from North America and Europe :*''Dryosaurus'', a North American ornithopod :*''Camptosaurus'', an ornithopod from North America and possibly Europe :*''Gargoyleosaurus'', a thyreophoran from North America :*''Archaeopteryx'', the first known bird, from Europe :*''Rhamphorhynchus (pterosaur), Rhamphorhynchus'' a long-tailed pterosaur from Europe :*''Pterodactylus'', a short-tailed pterosaur from Europe. :*''Ophthalmosaurus'', a very common sea-going ichthyosaur from what is now Europe and North America :*''Liopleurodon'', a medium-sized sea-going pliosaur from what is now Europe :*''Perisphinctes'', an ammonite


References

* * {{Authority control Late Jurassic, Geological epochs Jurassic geochronology