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 Moenkopi Formation is a geological formation that is spread across the U.S. states of New Mexico, northern Arizona, Nevada, southeastern California, eastern Utah and western Colorado. This unit is considered to be a group in Arizona. Part of the Colorado Plateau and Basin and Range, this red sandstone was laid down in the Lower Triassic and possibly part of the Middle Triassic, around 240 million years ago.
The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In New Mexico, it is often raised to the status of a geological group, the Chinle Group. Some authors have controversially considered the Chinle to be synonymous to the Dockum Group of eastern Colorado and New Mexico, western Texas, the Oklahoma panhandle, and southwestern Kansas. The Chinle Formation is part of the Colorado Plateau, Basin and Range, and the southern section of the Interior Plains. A probable separate depositional basin within the Chinle is found in northwestern Colorado and northeastern Utah. The southern portion of the Chinle reaches a maximum thickness of a little over 520 meters (1,710 ft). Typically, the Chinle rests unconformably on the Moenkopi Formation.
The Newark Supergroup, also known as the Newark Group, is an assemblage of Upper Triassic and Lower Jurassic sedimentary and volcanic rocks which outcrop intermittently along the east coast of North America. They were deposited in a series of Triassic basins, the Eastern North American rift basins, approximately 220–190 million years ago. The basins are characterized as aborted rifts, with half-graben geometry, developing parallel to the main rift of the Atlantic Ocean which formed as North America began to separate from Africa. Exposures of the Newark Supergroup extend from South Carolina north to Nova Scotia. Related basins are also found underwater in the Bay of Fundy. The group is named for the city of Newark, New Jersey.
The Beacon Supergroup is a geological formation exposed in Antarctica and deposited from the Devonian to the Triassic. The unit was originally described as either a formation or sandstone, and upgraded to group and supergroup as time passed. It contains a sandy member known as the Beacon Heights Orthoquartzite.
The Nam Phong Formation, which correlates to the Indosinian III Unconformity, is a geological formation in Thailand. It underlies the Khorat Group. It consists of resistant, red-brown micaceous sandstones, conglomerates, siltstones and mudstones of mainly fluvial origin. The sandstones are medium to very fine-grained and are usually calcareous. The conglomerates contain pebbles of quartz, brown and grey chert, and reddish brown siltstone. Cross bedding and plane-bed stratification are common in the sandstones and conglomerates. The sandstones and conglomerates make up approximately 30% of the formation. This sedimentary rock formation is found in Khon Kaen Province, Thailand. It is of Norian to Rhaetian age to age, and is notable for its fossils of early dinosaurs.
The Molteno Formation is a geological formation found in several localities in Lesotho and South Africa. It lies mainly south of Maseru, near Burgersdorp, Aliwal North, Dordrecht, Molteno, and Elliot. It extends as far north as Matatiele in the Eastern Cape. The formation's localities lie along the Drakensberg Mountains in Kwazulu-Natal, and near Ladybrand in the Free State of South Africa. The Molteno Formation is the lowermost of the three formations in the Stormberg Group of the greater Karoo Supergroup. The Molteno Formation represents the initial phase of preserved sedimentation of the Stormberg Group.
The Feltville Formation is a mapped bedrock unit primarily in New Jersey, with one known outlier in Pennsylvania and another one in New York. It is named for the Deserted Village of Feltville in Watchung Reservation, New Jersey, which is near where its type section was described by paleontologist Paul E. Olsen.
The Cow Branch Formation is a Late Triassic geologic formation in Virginia and North Carolina in the eastern United States. The formation consists of cyclical beds of black and grey lacustrine (lake) mudstone and shale. It is a konservat-lagerstätte renowned for its exceptionally preserved insect fossils, along with small reptiles, fish, and plants. Dinosaur tracks have also been reported from the formation.
The Norian is a division of the Triassic Period. It has the rank of an age (geochronology) or stage (chronostratigraphy). It lasted from ~227 to 208.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.
The Gettysburg Formation is a mapped bedrock unit consisting primarily of sandstones, conglomerates, and shales.
The Doswell Formation is a geologic unit of Upper Triassic age, part of the Newark Supergroup. The Doswell Formation was originally named to refer to a geological sequence which forms the lower part of the sedimentary fill of the Taylorsville Basin in Virginia and Maryland. This sequence was deposited by lakes and rivers in the developing rift basin. A 2016 study argued that several geological layers in Pennsylvania as well as the neighboring Richmond Basin of Virginia also qualified as components of the Doswell Formation.
The Culpeper Basin is one of the Newark Supergroup's Triassic rift basins. It lies east of the Appalachian Mountains and extends from the Madison County—Orange County line in Virginia to Frederick, Maryland. A diverse group of sedimentary rocks including siltstone, sandstone, and conglomerate within the basin were intruded by igneous rocks, which caused thermal metamorphism at the contact with sedimentary rock.
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 Cumnock Formation is a Late Triassic-age geologic formation in North Carolina. It is found in the Sanford sub-basin of the Deep River Basin, the southernmost of the large Mesozoic basins forming the Newark Supergroup. It is the middle unit of the Chatham Group, overlying the Pekin Formation and underlying the Sanford Formation. Both of these encompassing formations are primarily red sandstone. The Cumnock Formation, on the other hand, represents a sequence of darker lacustrine (lake) or paludal (swampy/marshy) sediments deposited in a tropical climate. These primarily include shales and coal, with some thin layers of coarser sediment such as siltstone and sandstone.
The Chatham Group is a Triassic-age geologic group in the eastern United States. It is one of the most fossiliferous sections of the Newark Supergroup, preserving much of the Late Triassic up until the Triassic-Jurassic mass extinction. The group was originally named to refer to Triassic rocks specifically within the Deep River Basin of North Carolina. Later studies have utilized it to encompass Late Triassic strata in most other sedimentary basins in the Newark Supergroup.
The Meriden Group is a geologic group, part of the Newark Supergroup, in Connecticut. It preserves fossils dating back to the Jurassic period.
The Pignola-Abriola section is a ~63 m long stratigraphic sequence of cherty limestones deposited in the Lagonegro Basin during the latest Norian and the early Rhaetian Stages. The main outcrop is on the western side of Mount Crocetta along the SP5 road connecting the villages of Pignola and Abriola. A smaller outcrop, overlapping the central part of the main section, is located near a former railway tunnel, few meters below the road level. The Pignola-Abriola section has been recently proposed as GSSP of the Rhaetian Stage.
Oncodella is an extinct genus of Late Triassic conodont. The genus was given the type species Oncodella idiodentica by Mosher (1968), on the basis of fossils from the Late Triassic of Austria. However, Mosher (1969) later revised the species name to Oncodella paucidentata, since identical fossils from the same area were previously given the name Hindeodella paucidentata by Mostler (1967).
The Sanford Formation is a Late Triassic (Norian)-age geologic formation in North Carolina. It is mainly found in the Sanford sub-basin of the Deep River Basin, the southernmost of the large Mesozoic basins forming the Newark Supergroup. It is the highest unit of the Chatham Group, overlying the dark lake and swamp sediments of the Cumnock Formation. The Sanford Formation is composed primarily of coarse red sediments such as conglomerates, sandstones, and mudstones. The conglomerate layers contain pebbles of schist and slate, with the occasional large boulders of granite.
United States