Woburn Sands Formation Stratigraphic range: Late Aptian- Early Albian | |
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Type | Geological formation |
Unit of | Lower Greensand Group |
Underlies | Gault Formation |
Overlies | Jurassic or older rocks, usually mudstones of the Ancholme Group like the Oxford Clay, Kimmeridge Clay and Ampthill Clay |
Thickness | up to 120 metres (390 ft) |
Lithology | |
Primary | Sandstone |
Other | Clay |
Location | |
Region | Europe |
Country | ![]() |
Extent | Bedfordshire, Buckinghamshire, Cambridgeshire |
Type section | |
Named for | Woburn, Bedfordshire |
Location | Disused fuller's earth workings between Woburn Sands and Woburn |
The Woburn Sands Formation is a geological formation in England. Part of the Lower Greensand Group, it is the only unit of the group where it occurs, and thus is sometimes simply referred to as the 'Lower Greensand' in these areas. It was deposited during the late Aptian to early Albian stages of the Early Cretaceous. The lithology consists of sandstone or loose sand with rare wisps or thin seams of clay. [1] The formation was extensively exploited in the 19th century for the "coprolite industry", with coprolite being a local term referring to phosphate nodules of varying origins (often the internal moulds of shells), named due to their resemblance to real coprolites. The formation contains reworked fossils of late Tithonian-Berriasian age from deposits that are no longer found locally, equivalent in age to the Sandringham Sand Formation in Norfolk and the Spilsby Sandstone of Lincolnshire, these include Dicranodonta and the ammonite Subcraspedites. [2] Reworked dinosaur material is known from the Potton locality within the formation. [3]
Greensand or green sand is a sand or sandstone which has a greenish color. This term is specifically applied to shallow marine sediment that contains noticeable quantities of rounded greenish grains. These grains are called glauconies and consist of a mixture of mixed-layer clay minerals, such as smectite and glauconite mica. Greensand is also loosely applied to any glauconitic sediment.
Weald Clay or the Weald Clay Formation is a Lower Cretaceous sedimentary rock underlying areas of South East England, between the North and South Downs, in an area called the Weald Basin It is the uppermost unit of the Wealden Group of rocks within the Weald Basin, and the upper portion of the unit is equivalent in age to the exposed portion of the Wessex Formation on the Isle of Wight. It predominantly consists of thinly bedded mudstone. The un-weathered form is blue/grey, and the yellow/orange is the weathered form, it is used in brickmaking.
The Two Medicine Formation is a geologic 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 Lohan Cura Formation is a geologic formation with outcrops in the Argentine provinces of Río Negro, Neuquén, and Mendoza. It is the second oldest Cretaceous terrestrial formation in the Neuquén Basin.
The Wealden Group, occasionally also referred to as the Wealden Supergroup, is a group in the lithostratigraphy of southern England. The Wealden group consists of paralic to continental (freshwater) facies sedimentary rocks of Berriasian to Aptian age and thus forms part of the English Lower Cretaceous. It is composed of alternating sands and clays. The sandy units were deposited in a flood plain of braided rivers, the clays mostly in a lagoonal coastal plain.
The Cedar Mountain Formation is the name given to a distinctive sedimentary geologic formation in eastern Utah. The formation was named for Cedar Mountain in northern Emery County, Utah, where William Lee Stokes first studied the exposures in 1944.
The Cloverly Formation is a geological formation of Early Cretaceous age that is present in parts of Montana, Wyoming, Colorado and Utah in the western United States. It was named for a post office on the eastern side of the Bighorn Basin in Wyoming by N.H. Darton in 1904. The sedimentary rocks of formation were deposited in floodplain environments and contain vertebrate fossils, including a diverse assemblage of dinosaur remains. In 1973, the Cloverly Formation Site was designated as a National Natural Landmark by the National Park Service.
The Dakota is a sedimentary geologic unit of formation and group rank composed of sandstones, mudstones, and shales deposited in the late-Early to early-Late Cretaceous Western Interior Seaway. The unit is noted for being 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, and preserving both dinosaur footprints and early deciduous tree leaves.
The Xīnmínbǎo Group is a group of geological formations in north central China. They occur across a large depression between the Altai mountains of Mongolia to the north and the Qilian mountains of the Qinghai Plateau to the south, in the Gōngpóquán (公婆泉) and Suànjǐngzi (算井子) basins, and also in the neighbouring Jiuquan Basin.
The Twin Mountains Formation, also known as the Twin Mountain Formation, is a sedimentary rock formation, within the Trinity Group, found in Texas of the United States of America. It is a terrestrial formation of Aptian age, and is notable for its dinosaur fossils. Dinosaurs from this formation include the large theropod Acrocanthosaurus, the sauropod Sauroposeidon, as well as the ornithopods Tenontosaurus and Convolosaurus. It is the lowermost unit of the lower Cretaceous, lying unconformably on Carboniferous strata. It is overlain by the Glen Rose Formation. It is the lateral equivalent of the lower part of the Antlers Formation.
The Arundel Formation, also known as the Arundel Clay, is a clay-rich sedimentary rock formation, within the Potomac Group, found in Maryland of the United States of America. It is of Aptian age. This rock unit had been economically important as a source of iron ore, but is now more notable for its dinosaur fossils. It consists of clay lenses within depressions in the upper part of the Patuxent Formation that may represent oxbow swamp facies. It is named for Anne Arundel County, Maryland.
The Vectis Formation is a geological formation on the Isle of Wight and Swanage, England whose strata were formed in the lowermost Aptian, approximately 125 million years ago. The environment of deposition was that of a freshwater coastal lagoon with occasional marine influence after the early Aptian marine transgression, transitioning from the floodplain environment of the underlying Wessex Formation. The primary lithology is of laminated grey mudstones. The Vectis Formation is composed of three geological members: the Shepherds Chine member, the Barnes High Sandstone member, and the Cowleaze Chine member. It is overlain by the fully marine Atherfield Clay Formation, part of the Lower Greensand Group. Dinosaur remains are among the fossils that have been recovered from the formation.
The Papo Seco Formation is a geological formation in Portugal, whose strata date back to the Early Cretaceous. Dinosaur fossils are among the fossils that have been recovered from the formation.
The Rayoso Formation is a geological formation in the Neuquén Province of Argentina whose strata date back to the Aptian stage of the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.
The Dinosaur Beds is a geological formation in Malawi whose strata date back to the Early Cretaceous. The age of the deposit is poorly constrained, but is likely to date from the Barremian to Aptian. Dinosaurs, turtles and crocodyliomorphs remains are among the fossils that have been recovered from the formation. It is correlated with the Galula Formation in Tanzania. It consists of two members, a lower unfossiliferous member consisting of deep red stained sandstones, and an upper fossiliferous member consisting of white sands and grey to red mudstones and siltstones. The upper member is 210 m thick in the vicinity of the CD-9 locality.
The Yezo Group is a stratigraphic group in Hokkaido, Japan and Sakhalin, Russia which is primarily Late Cretaceous in age. It is exposed as roughly North-South trending belt extending 1,500 kilometres through central Hokkaido from Urakawa to Cape Sōya and Sakhalin from the south coast to Alexandrovsk-Sakhalinsky District. It consists of marine forearc basin sediments, typically turbiditic and bioturbated mudstones and sandstones with subordinate conglomerate primarily deposited on the continental shelf and slope of the ancient Yezo subduction margin. It forms a continuous depositional sequence with the Sorachi Group, which overlies the Horokanai Ophiolite. The sequence gradually shallows upwards with the terminal Hakobuchi Formation representing a fluvial-inner shelf environment.
The Lower Greensand Group is a geological unit, part of the quite widely remaining underlying geological structure of southeast England. South of London in the counties of West Sussex, East Sussex, Surrey and Kent, which together form the wider Weald, the Lower Greensand can usually be subdivided to formational levels with varying properties into the Atherfield Clay Formation, the Hythe Formation, the Sandgate Formation, and the Folkestone Formation. North and west of London – including Cambridgeshire, Bedfordshire and Buckinghamshire – it is referred to as the Woburn Sands Formation. In Oxfordshire it is known as the Faringdon Sand. In North Wiltshire as the Calne Sands Formation and in parts of Wiltshire, Oxfordshire and Buckinghamshire as the Seend Ironstone Formation.
The geology of East Sussex is defined by the Weald–Artois anticline, a 60 kilometres (37 mi) wide and 100 kilometres (62 mi) long fold within which caused the arching up of the chalk into a broad dome within the middle Miocene, which has subsequently been eroded to reveal a lower Cretaceous to Upper Jurassic stratigraphy. East Sussex is best known geologically for the identification of the first dinosaur by Gideon Mantell, near Cuckfield, to the famous hoax of the Piltdown man near Uckfield.
The Tunbridge Wells Sand Formation is a geological unit which forms part of the Wealden Group and the uppermost and youngest part of the unofficial Hastings Beds. These geological units make up the core of the geology of the Weald in the English counties of West Sussex, East Sussex and Kent.
The geology of West Sussex in southeast England comprises a succession of sedimentary rocks of Cretaceous age overlain in the south by sediments of Palaeogene age. The sequence of strata from both periods consists of a variety of sandstones, mudstones, siltstones and limestones. These sediments were deposited within the Hampshire and Weald basins. Erosion subsequent to large scale but gentle folding associated with the Alpine Orogeny has resulted in the present outcrop pattern across the county, dominated by the north facing chalk scarp of the South Downs. The bedrock is overlain by a suite of Quaternary deposits of varied origin. Parts of both the bedrock and these superficial deposits have been worked for a variety of minerals for use in construction, industry and agriculture.
Coordinates: 52°02′10″N0°23′26″W / 52.0360°N 0.3906°W
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