|Subdivision of the Jurassic system|
according to the ICS, as of 2017.
In European lithostratigraphy, 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.
The Late Jurassic is divided into three ages, which correspond with the three (faunal) stages of Upper Jurassic rock:
|Tithonian||(152.1 ± 0.9 – 145.0 ± 0.8 Ma)|
|Kimmeridgian||(157.3 ± 1.0 – 152.1 ± 0.9 Ma)|
|Oxfordian||(163.5 ± 1.0 – 157.3 ± 1.0 Ma)|
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During the Late Jurassic epoch, Pangaea broke up into two supercontinents, Laurasia to the north, and Gondwana to the south. The result of this break-up was the spawning of the Atlantic Ocean. However, at this time, the Atlantic Ocean was relatively narrow.
Life forms of the epochEdit
This epoch is well known for many famous types of dinosaurs, such as the sauropods, the theropods, the thyreophorans, and the ornithopods. Other animals, such as crocodiles and the first birds, appeared in the Jurassic. Listed here are only a few of the many Jurassic animals:
- Camarasaurus, 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 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.
- Owen 1987.
- Gradstein, F.M.; Ogg, J.G.; Schmitz, M.D.; Ogg, G.M. (editors) (2012). The Geologic Timescale 2012 (volume 1). Elsevier. p. 744. ISBN 978-0-44-459390-0.CS1 maint: Uses authors parameter (link)
- Owen, Donald E. (March 1987). "Commentary: Usage of Stratigraphic Terminology in Papers, Illustrations, and Talks". Journal of Sedimentary Petrology. 57 (2): 363–372.
- Kazlev, M. Alan (2002-06-28). "Late Jurassic — The Malm Epoch: The Acme of the Dinosaurs". Palæos. Retrieved 2014-10-23.