The Mesozoic Era is the second-to-last 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 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.
The Triassic–Jurassic (Tr-J) extinction event (TJME), often called the end-Triassic extinction, was a Mesozoic extinction event that marks the boundary between the Triassic and Jurassic periods, 201.4 million years ago, and is one of the top five major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans. In the seas, the entire class of conodonts and 23–34% of marine genera disappeared. On land, all archosauromorphs other than crocodylomorphs, pterosaurs, and dinosaurs became extinct; some of the groups which died out were previously abundant, such as aetosaurs, phytosaurs, and rauisuchids. Some remaining non-mammalian therapsids and many of the large temnospondyl amphibians had become extinct prior to the Jurassic as well. However, there is still much uncertainty regarding a connection between the Tr-J boundary and terrestrial vertebrates, due to a lack of terrestrial fossils from the Rhaetian (latest) stage of the Triassic. What was left fairly untouched were plants, crocodylomorphs, dinosaurs, pterosaurs and mammals; this allowed the dinosaurs, pterosaurs, and crocodylomorphs to become the dominant land animals for the next 135 million years.
The Siberian Traps is a large region of volcanic rock, known as a large igneous province, in Siberia, Russia. The massive eruptive event that formed the traps is one of the largest known volcanic events in the last 500 million years.
A flood basalt is the result of a giant volcanic eruption or series of eruptions that covers large stretches of land or the ocean floor with basalt lava. Many flood basalts have been attributed to the onset of a hotspot reaching the surface of the Earth via a mantle plume. Flood basalt provinces such as the Deccan Traps of India are often called traps, after the Swedish word trappa, due to the characteristic stairstep geomorphology of many associated landscapes.
The High Atlas, also called the Grand Atlas, is a mountain range in central Morocco, North Africa, the highest part of the Atlas Mountains.
A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive and extrusive, arising when magma travels through the crust towards the surface. The formation of LIPs is variously attributed to mantle plumes or to processes associated with divergent plate tectonics. The formation of some of the LIPs in the past 500 million years coincide in time with mass extinctions and rapid climatic changes, which has led to numerous hypotheses about causal relationships. LIPs are fundamentally different from any other currently active volcanoes or volcanic systems.
The Rhaetian is the latest age of the Triassic Period or the uppermost stage of the Triassic System. It was preceded by the Norian and succeeded by the Hettangian. The base of the Rhaetian lacks a formal GSSP, though candidate sections include Steinbergkogel in Austria and Pignola-Abriola in Italy. The end of the Rhaetian is more well-defined. According to the current ICS system, the Rhaetian ended 201.4 ± 0.2 Ma.
The Karoo Supergroup is the most widespread stratigraphic unit in Africa south of the Kalahari Desert. The supergroup consists of a sequence of units, mostly of nonmarine origin, deposited between the Late Carboniferous and Early Jurassic, a period of about 120 million years.
The Forest Sandstone is a geological formation in southern Africa, dating to roughly between 200 and 190 million years ago and covering the Hettangian to Sinemurian stages of the Jurassic Period in the Mesozoic Era. As its name suggests, it consists mainly of sandstone.
Gondwana was a large landmass, sometimes referred to as a supercontinent. It was formed by the accretion of several cratons, beginning c. 800 to 650Ma with the East African Orogeny, the collision of India and Madagascar with East Africa, and culminating in c. 600 to 530 Ma with the overlapping Brasiliano and Kuunga orogenies, the collision of South America with Africa, and the addition of Australia and Antarctica, respectively. Eventually, Gondwana became the largest piece of continental crust of the Palaeozoic Era, covering an area of some 100,000,000 km2 (39,000,000 sq mi), about one-fifth of the Earth's surface. It fused with Euramerica during the Carboniferous to form Pangea. It began to separate from northern Pangea (Laurasia) during the Triassic, and started to fragment during the Early Jurassic. The final stages of break-up, involving the separation of Antarctica from South America and Australia, occurred during the Paleogene (from around 66 to 23 million years ago. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. To differentiate it from the Indian region of the same name, it is also commonly called Gondwanaland.
The Upper Karoo Group is a sequence of Triassic to Early Jurassic sedimentary and volcanic rocks found in Botswana, Zambia, and Zimbabwe.
The Midland Formation is a Mesozoic geological formation in the Culpeper Basin of Virginia. It is a sedimentary unit which formed in a short period of time between the first two basalt flows in the basin: the Hickory Grove and Mount Zion Church basalts. The most common rocks in the formation are dark reddish interbedded sandstones and siltstones, representative of fluvial (stream) environments. Rare but fossiliferous calcareous shale and limestone also occurs, representing recurring lacustrine (lake) conditions. The Midland Formation is considered equivalent to the Shuttle Meadow Formation of the Hartford Basin, the Feltville Formation of the Newark Basin, and the Bendersville Formation of the Gettysburg Basin. Some sources prefer to classify the Midland Formation as part of the Shuttle Meadow Formation.
The Panjal Traps or the Tethyan Plume is a large igneous province (LIP) that erupted during the Early–Middle Permian in what is now north-western India. The Panjal Traps are associated with the opening of the Neo-Tethys Ocean, which resulted in the dispersal of the Cimmerian continental blocks from the north-eastern margin of Gondwana and possibly the break-up of this old and large continent. In the Zanskar-Spliti-Lahaul area the 30–150 m (98–492 ft)-thick basalts of the Panjal Traps are mostly exposed as massive (terrestrial) lava flows, but also as (marine) pillow lavas and hyaloclastites.
The Mawson Formation is a geological formation in Antarctica, dating to roughly between 182 and 177 million years ago and covering the Toarcian stages of the Jurassic Period in the Mesozoic Era. Vertebrate remains are known from the formation. The Mawson Formation is the South Victoria Land equivalent of the Karoo Large Igneous Province in South Africa, as well the Lonco Trapial Formation and the Cañadón Asfalto Formation of Argentina.
The Azilal Formation, also known as Toundoute Continental Series and Wazzant Formation, is a geological unit in the Azilal, Béni-Mellal, Ouarzazate, Tinerhir and Errachidia provinces of the High Atlas of Morocco, that cover the Latest Pliensbachian to Middle Aalenian stages of the Jurassic Period. It is a terrestrial deposit which overlies marine dolomites of equivalent age to the Rotzo Formation of Italy, mostly part of the Aganane Formation. Dinosaur remains, such the sauropod Tazoudasaurus and the basal ceratosaur Berberosaurus are known from the unit, along with several undescribed genera. The Units inside the group have been considered individual on the past, being a division of the so-called "Couches rouges", and subdivided by a supposed geological scale. The strata of the group extends towards the Central High Atlas, covering different anticlines, and topographic accidents along the range of the Mountains. Although new studies have suggested that the strata is coeval in age, and should be referred to as a unique unit. The formation is best assigned to an alluvial environment occasionally interrupted by shallow marine incursions and marks a dramatic decrease of the carbonate productivity under increasing terrigenous sedimentation. The Azilal Formation consists mainly of claystones rich in continental plant debris and laminated microbial facies. The toarcian High Atlas is divided in 5 units: the continental layers with paralic deposits belong to the Azilal, along the shoreface layers of the Tagoudite Formation and Tafraout Formation, both connected with the offshore Ait Athmane Formation and the deeper shelf deposits of the Agoudim 1 Formation.
The Madagascar flood basalt, also known as the Madagascar large igneous province (LIP), is one of the major magmatic events of the Late Cretaceous. They cover a large area of basaltic and rhyolitic lava flows that erupted during an episode of widespread basaltic volcanism during the Cretaceous period. The flood basalts are characterized by lava flows, dykes, sills, and intrusions, and other volcanic features include plugs, scoria, and spatter cones. Tholeiitic basalt constitutes the primary rock type.
The Catharpin Creek Formation is a Late Triassic geologic formation in Maryland and Virginia. It is found along the western edge of the Culpeper Basin, one of the largest sedimentary basins in the Newark Supergroup. Compared to the underlying Bull Run Formation, the Catharpin Creek Formation is dominated by much coarser sedimentary rocks such as sandstone and conglomerate. The base of the formation is reddish arkosic sandstone, which grades into drabber thin-bedded siltstone and shale in cyclical sequences.
The Parnaíba Basin is a large cratonic sedimentary basin located in the North and Northeast portion of Brazil. About 50% of its areal distribution occurs in the state of Maranhão, and the other 50% occurring in the state of Pará, Piauí, Tocantins, and Ceará. It is one of the largest Paleozoic basins in the South American Platform. The basin has a roughly ellipsoidal shape, occupies over 600,000 km2, and is composed of ~3.4 km of mainly Paleozoic sedimentary rock that overlies localized rifts.
