Rolling Downs Group | |
---|---|
Stratigraphic range: Mid Barremian-Early Turonian ~ | |
Type | Group |
Sub-units |
|
Underlies | Quaternary Lake Eyre Basin sediments |
Overlies | Cadna-Owie Formation, Bungil Formation |
Thickness | up to 1,200 m (3,900 ft) |
Lithology | |
Primary | Mudstone, siltstone, sandstone |
Other | Limestone, claystone |
Location | |
Coordinates | 22°36′S143°00′E / 22.6°S 143.0°E |
Region | New South Wales Queensland South Australia |
Country | Australia |
Extent | Eromanga & Surat Basins |
The Rolling Downs Group is a stratigraphic group present in the Eromanga and Surat Basins in eastern Australia, [1] which was deposited between the mid Barremian to early Turonian of the Cretaceous period. It primarily consists of nearshore shallow marine sediments deposited in the Eromanga Sea, though the uppermost and terminal members, the Winton Formation and the Griman Creek Formation represents freshwater deposits. It is notable for its fossil content including many dinosaurs and mammals, as well as opal. A relict species of dicynodont was suggested to have been found in these rocks, [2] but is more likely to be misidentified pieces of a Cenozoic marsupial from younger sediments. [3]
Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivores that typically bore a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typically toothless beak, unique amongst all synapsids. Dicynodonts first appeared in Southern Pangaea during the mid-Permian, ca. 270–260 million years ago, and became globally distributed and the dominant herbivorous animals in the Late Permian, ca. 260–252 Mya. They were devastated by the end-Permian Extinction that wiped out most other therapsids ca. 252 Mya. They rebounded during the Triassic but died out towards the end of that period. They were the most successful and diverse of the non-mammalian therapsids, with over 70 genera known, varying from rat-sized burrowers to elephant-sized browsers.
Placerias is an extinct genus of dicynodonts that lived during the Carnian to the Norian age of the Triassic Period. Placerias belongs to a group of dicynodonts called Kannemeyeriiformes, which was the last known group of dicynodonts before the taxon became extinct at the end of the Triassic.
The South Polar region of the Cretaceous comprised the continent of East Gondwana–modern day Australia, Zealandia, and Antarctica–a product of the break-up of Gondwana in the Cretaceous Period. The southern region, during this time, was much warmer than it is today, ranging from perhaps 4–8 °C (39–46 °F) in the latest Cretaceous Maastrichtian in what is now southeastern Australia. This prevented permanent ice sheets from developing and fostered polar forests, which were largely dominated by conifers, cycads, and ferns, and relied on a temperate climate and heavy rainfall. Major fossil-bearing geological formations that record this area are: the Santa Marta and Sobral Formations of Seymour Island off the Antarctic Peninsula; the Snow Hill Island, Lopez de Bertodano, and the Hidden Lake Formations on James Ross Island also off the Antarctic Peninsula; and the Eumeralla and Wonthaggi Formations in Australia.
The Oldman Formation is a stratigraphic unit of Late Cretaceous age that underlies much of southern Alberta, Canada. It consists primarily of sandstones that were deposited in fluvial channel and floodplain environments. It was named for exposures along the Oldman River between its confluence with the St. Mary River and the city of Lethbridge, and it is known primarily for its dinosaur remains and other fossils.
The Two Medicine Formation is a geological formation, or rock body, in northwestern Montana and southern Alberta that was deposited between 83.5 ± 0.7 Ma and 70.6 ± 3.4 Ma, during Campanian time. It crops out to the east of the Rocky Mountain Overthrust Belt, and the western portion of this formation is folded and faulted while the eastern part, which thins out into the Sweetgrass Arch, is mostly undeformed plains. Below the formation are the nearshore deposits of the Virgelle Sandstone, and above it is the marine Bearpaw Shale. Throughout the Campanian, the Two Medicine Formation was deposited between the western shoreline of the Late Cretaceous Interior Seaway and the eastward advancing margin of the Cordilleran Overthrust Belt. The Two Medicine Formation is mostly sandstone, deposited by rivers and deltas.
The Daptocephalus Assemblage Zone is a tetrapod assemblage zone or biozone found in the Adelaide Subgroup of the Beaufort Group, a majorly fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. This biozone has outcrops located in the upper Teekloof Formation west of 24°E, the majority of the Balfour Formation east of 24°E, and the Normandien Formation in the north. It has numerous localities which are spread out from Colesberg in the Northern Cape, Graaff-Reniet to Mthatha in the Eastern Cape, and from Bloemfontein to Harrismith in the Free State. The Daptocephalus Assemblage Zone is one of eight biozones found in the Beaufort Group and is considered Late Permian (Lopingian) in age. Its contact with the overlying Lystrosaurus Assemblage Zone marks the Permian-Triassic boundary.
The Pristerognathus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the upper Abrahamskraal Formation and lowermost Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching not more than 300 metres (980 ft), occur just east of Sutherland through to Beaufort West in the south and Victoria West in the north. Exposures are also found west of Colesberg and south of Graaff-Reinet. The Pristerognathus Assemblage Zone is the third biozone of the Beaufort Group.
The Tropidostoma Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the lower Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 240 metres (790 ft), occur from east of Sutherland through to Beaufort West and Victoria West, to areas south of Graaff-Reinet. Its northernmost exposures occur west/north-west of Colesberg. The Tropidostoma Assemblage Zone is the fourth biozone of the Beaufort Group.
The Dakota is a sedimentary geologic unit name of formation and group rank in Midwestern North America. The Dakota units are generally composed of sandstones, mudstones, clays, and shales deposited in the Mid-Cretaceous opening of the Western Interior Seaway. The usage of the name Dakota for this particular Albian-Cenomanian strata is exceptionally widespread; from British Columbia and Alberta to Montana and Wisconsin to Colorado and Kansas to Utah and Arizona. It is famous for producing massive colorful rock formations in the Rocky Mountains and the Great Plains of the United States, and for preserving both dinosaur footprints and early deciduous tree leaves.
The Winton Formation is a Cretaceous geological formation in central-western Queensland, Australia. It is late Albian to early Turonian in age. The formation blankets large areas of central-western Queensland. It consists of sedimentary rocks such as sandstone, siltstone and claystone. The sediments that make up these rocks represent the remnants of the river plains that filled the basin left by the Eromanga Sea - an inland sea that covered large parts of Queensland and central Australia at least four times during the Early Cretaceous. Great meandering rivers, forest pools and swamps, creeks, lakes and coastal estuaries all left behind different types of sediment.
Cratochelone is an extinct genus of sea turtle in the family Protostegidae and containing a single species Cratochelone berneyi. The species is known only from the mid to late Albian Toolebuc Formation, part of the Rolling Downs Group, in the Hughenden of Central northern Queensland, Australia.
The Toolebuc Formation is a geological formation that extends from Queensland across South Australia and the Northern Territory in Australia, whose strata date back to the Albian stage of the Early Cretaceous. Dinosaurs, pterosaurs, plesiosaurs, ichthyosaurs, protostegid turtles, sharks, chimaeroids and bony fish remains are among the fossils that have been recovered from the formation.
The Allaru Formation, also known as the Allaru Mudstone, is a geological formation in Queensland, Australia, whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.
The Marree Subgroup, previously described as Maree Formation and Marree Formation, is a geological subgroup in the Eromanga Basin of South Australia whose strata date back to the Aptian. The subgroup was first described as a formation by Forbes in 1966. Dinosaur remains are among the fossils that have been recovered from the formation.
The Wonthaggi Formation is an informal geological formation in Victoria, Australia whose strata date back to the Early Cretaceous. It is part of the Strzelecki Group within the Gippsland Basin. Dinosaur remains are among the fossils that have been recovered from the formation. It is partially equivalent to the Eumeralla Formation.
The Wallumbilla Formation is an Aptian geologic formation found in Australia. Plesiosaur and theropod remains are among the fossils that have been recovered from its strata.
Geologically the Australian state of New South Wales consists of seven main regions: Lachlan Fold Belt, the Hunter-Bowen Orogeny or New England Orogen (NEO), the Delamerian Orogeny, the Clarence Moreton Basin, the Great Artesian Basin, the Sydney Basin, and the Murray Basin.
The geology of Queensland can be subdivided into several regions with different histories. Along the east coast is a complex of Palaezoic to Cainozoic rocks while much of the rest of the state is covered by Cretaceous and Cainozoic rocks. A Precambrian basement is found in the north west and Cape York regions. The Thomson Orogen occurs in the central and southern parts of Queensland, but is mostly covered by younger basins.
Australian Age of Dinosaurs Ltd. (AAOD) is a nonprofit organization located in Winton, Queensland, founded by David Elliott and Judy Elliott in 2002. The organization’s activities include the operation of the Australian Age of Dinosaurs Museum of Natural History, which holds annual dinosaur digs in the Winton Formation of Western Queensland and oversees the year-round operation of Australia's most productive dinosaur fossil preparation laboratory. Since 2005, the AAOD Museum has accumulated the largest collection of Australian dinosaur fossils in the world and holds the holotype specimens of Diamantinasaurus matildae ("Matilda"), Savannasaurus elliottorum ("Wade"), Australovenator wintonensis ("Banjo"), Australia's most complete theropod skeleton, Ferrodraco lentoni, the first pterosaur to be named from the Winton Formation, and Confractosuchus sauroktonos. The museum is open to the public daily from April to October and is open six days a week from November to March. The site of the museum was designated a dark-sky preserve, the first International Dark-Sky Sanctuary in Australia, in 2019.
The Bulldog Shale is a formation of Early Cretaceous age that forms part of the Marree Subgroup of the Rolling Downs Group, located in the Eromanga Basin of South Australia, Queensland and New South Wales.