The Mesozoic Era is the penultimate era of Earth's geological history, lasting from about 252 to 66 million years ago, comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of gymnosperms and of archosaurian reptiles, such as the dinosaurs; a hot greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of the three eras since complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic.
The Phanerozoic is the current and the latest of the four geologic eons in the Earth's geologic time scale, covering the time period from 538.8 million years ago to the present. It is the eon during which abundant animal and plant life has proliferated, diversified and colonized various niches on the Earth's surface, beginning with the Cambrian period when animals first developed hard shells that can be clearly preserved in the fossil record. The time before the Phanerozoic, collectively called the Precambrian, is now divided into the Hadean, Archaean and Proterozoic eons.
The Triassic is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago (Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic.
Laurasia was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around 335 to 175 million years ago (Mya), the other being Gondwana. It separated from Gondwana 215 to 175 Mya during the breakup of Pangaea, drifting farther north after the split and finally broke apart with the opening of the North Atlantic Ocean c. 56 Mya. The name is a portmanteau of Laurentia and Asia.
Panthalassa, also known as the Panthalassic Ocean or Panthalassan Ocean, was the vast superocean that encompassed planet Earth and surrounded the supercontinent Pangaea, the latest in a series of supercontinents in the history of Earth. During the Paleozoic–Mesozoic transition, the ocean occupied almost 70% of Earth's surface, with the supercontinent Pangaea taking up less than half. The original, ancient ocean floor has now completely disappeared because of the continuous subduction along the continental margins on its circumference. Panthalassa is also referred to as the Paleo-Pacific or Proto-Pacific because the Pacific Ocean is a direct continuation of Panthalassa.
Cynodontia is a clade of eutheriodont therapsids that first appeared in the Late Permian, and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extinct ancestors and close relatives (Mammaliaformes), having evolved from advanced probainognathian cynodonts during the Late Triassic.
Megazostrodon is an extinct genus of basal mammaliaforms belonging to the order Morganucodonta. It is approximately 200 million years old. Two species are known: M. rudnerae from the Early Jurassic of Lesotho and South Africa, and M. chenali from the Late Triassic of France.
Oligokyphus is an extinct genus of herbivorous tritylodontid cynodont known from the Late Triassic to Early Jurassic of Europe, Asia and North America.
Tritylodon is an extinct genus of tritylodonts, one of the most advanced group of cynodont therapsids. They lived in the Early Jurassic and possibly Late Triassic periods along with dinosaurs. They also shared many characteristics with mammals, and were once considered mammals because of overall skeleton construction. That was changed due to them retaining the vestigial amniote jawbones and a different skull structure. Tritylodonts are now regarded as non-mammalian synapsids.
The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between 237 Ma and 201.4 Ma. It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. The corresponding series of rock beds is known as the Upper Triassic. The Late Triassic is divided into the Carnian, Norian and Rhaetian ages.
Afrovenator is a genus of megalosaurid theropod dinosaur from the Middle or Late Jurassic Period on the Tiourarén Formation and maybe the Irhazer II Formation of the Niger Sahara region in northern Africa. Afrovenator represents the only properly identified Gondwanan megalosaur, with proposed material of the group present in the Late Jurassic on Tacuarembó Formation of Uruguay and the Tendaguru Formation of Tanzania.
The Franciscan Complex or Franciscan Assemblage is a geologic term for a late Mesozoic terrane of heterogeneous rocks found throughout the California Coast Ranges, and particularly on the San Francisco Peninsula. It was named by geologist Andrew Lawson, who also named the San Andreas fault that defines the western extent of the assemblage.
The geological history of the Earth follows the major geological events in Earth's past based on the geological time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System.
Gondwana was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia, Zealandia, Arabia, and the Indian Subcontinent.
Pangaea or Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million years ago, and began to break apart about 200 million years ago, at the end of the Triassic and beginning of the Jurassic. In contrast to the present Earth and its distribution of continental mass, Pangaea was C-shaped, with the bulk of its mass stretching between Earth's northern and southern polar regions and surrounded by the superocean Panthalassa and the Paleo-Tethys and subsequent Tethys Oceans. Pangaea is the most recent supercontinent to have existed and the first to be reconstructed by geologists.
The Elliot Formation is a geological formation and forms part of the Stormberg Group, the uppermost geological group that comprises the greater Karoo Supergroup. Outcrops of the Elliot Formation have been found in the northern Eastern Cape, southern Free State, and in the eastern KwaZulu-Natal provinces of South Africa. Outcrops and exposures are also found in several localities in Lesotho such as Qacha's Neck, Hill Top, Quthing, and near the capital, Maseru. The Elliot Formation is further divided into the lower (LEF) and upper (UEF) Elliot formations to differentiate significant sedimentological differences between these layers. The LEF is dominantly Late Triassic (Norian-Hettangian) in age while the UEF is mainly Early Jurassic (Sinemurian-Pliensbachian) and is tentatively regarded to preserve a continental record of the Triassic-Jurassic boundary in southern Africa. This geological formation is named after the town of Elliot in the Eastern Cape, and its stratotype locality is located on the Barkly Pass, 9 km north of the town.
The La Boca Formation is a geological formation in Tamaulipas state, northeast Mexico. It was thought to date back to the Early Jurassic, concretely the Pliensbachian stage epoch. Although, the latest studies had proven that the local Vulcanism, related to the aperture of the Atlantic Ocean and the several Rift Events, that continue until the Bajocian, while the unit itself was likely deposited between the earliest Pliensbachian, as proven by zircon with the fossil taxa deposited on the rocks above, likely of Late Pliensbachian-Lower Toarcian age, and the upper section of Late Toarcian-Late Aalenian age. Due to successions of Aalenian depositional systems on the upper layers of the Huizachal Canyon, has been delimited the formation to the Toarcian stage, being the regional equivalent of the Moroccan Azilal Formation. Deposits of Late Triassic Age referred to this unit have been reclassified in a new formation, El Alamar Formation. In North America, La Boca Formation was found to be a regional equivalent of the Eagle Mills redbeds of southern United States, the Todos Santos Formation of southern Mexico and the Barracas Group of the Sonora desert region.
The Stormberg Group is one of the four geological groups that comprises the Karoo Supergroup in South Africa. It is the uppermost geological group representing the final phase of preserved sedimentation of the Karoo Basin. The Stormberg Group rocks are considered to range between Lower Triassic (Olenekian) to Lower Jurassic (Pliensbachian) in age. These estimates are based on means of geological dating including stratigraphic position, lithostratigraphic and biostratigraphic correlations, and palynological analyses.
Kayentatherium is an extinct genus of tritylodontid cynodonts that lived during the Early Jurassic. It is one of two tritylodonts from the Kayenta Formation of northern Arizona, United States.
Paleontology in Oregon refers to paleontological research occurring within or conducted by people from the U.S. state of Oregon. Oregon's geologic record extends back approximately 400 million years ago to the Devonian period, before which time the state's landmass was likely submerged under water. Sediment records show that Oregon remained mostly submerged until the Paleocene period. The state's earliest fossil record includes plants, corals, and conodonts. Oregon was covered by seaways and volcanic islands during the Mesozoic era. Fossils from this period include marine plants, invertebrates, ichthyosaurs, pterosaurs, and traces such as invertebrate burrows. During the Cenozoic, Oregon's climate gradually cooled and eventually yielded the environments now found in the state. The era's fossils include marine and terrestrial plants, invertebrates, fish, amphibians, turtles, birds, mammals, and traces such as eggs and animal tracks.
