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Hakobuchi Formation
The Hakobuchi Formation is a geological formation in Hokkaido, Japan. It is the uppermost unit of the Yezo Group, being early Maastrichtian in age. It consists of bioturbated glauconitic sandstones, siltstones and conglomerates with coaly mudstone and minor tuffite. It was deposited in a continental shelf setting. It is noted for its fossil content with the invertebrates mainly consisting of bivalves and ammonites. With vertebrates including the mosasaurs '' Mosasaurus hobetsuensis'' and ''Phosphorosaurus ponpetelegans''. As well the sea turtle '' Mesodermochelys''Hirayama R, Chitoku T. (1996). "Family Dermochelyidae (Superfamily Chelonioidea) from the Upper Cretaceous of North Japan". ''Transactions and proceedings of the Palaeontological Society of Japan. New series'' 184: 597-622online, retrieved 28 July 2008/ref> and the hadrosaurid dinosaur ''Kamuysaurus ''Kamuysaurus'' is a genus of herbivorous edmontosaurin saurolophine hadrosaurid dinosaur from Late Cretaceous Maast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioturbation
Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a primary driver of biodiversity. The formal study of bioturbation began in the 1800s by Charles Darwin experimenting in his garden. The disruption of aquatic sediments and terrestrial soils through bioturbating activities provides significant ecosystem services. These include the alteration of nutrients in aquatic sediment and overlying water, shelter to other species in the form of burrows in terrestrial and water ecosystems, and soil production on land.Shaler, N. S., 1891, The origin and nature of soils, in Powell, J. W., ed., USGS 12th Annual report 1890-1891: Washington, D.C., Government Printing Office, p. 213-45. Bioturbators are deemed ecosystem engineers because they alter resource availability to other species through the physical ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kamuysaurus
''Kamuysaurus'' is a genus of herbivorous edmontosaurin saurolophine hadrosaurid dinosaur from Late Cretaceous Maastrichtian marine deposits of the Yezo Group (Hakobuchi Formation) in the Hobetsu area near the town of Mukawa, Hokkaido in Japan. Discovery In 2003, amateur paleontologist Yoshiyuki Horita at the Shirafunezawa Creek discovered the tail of a euornithopod. An entire skeleton was in 2013 and 2014 uncovered by teams of the Hobetsu Museum and the Hokkaido University Museum. The find was nicknamed ''Mukawaryu'', the "Dragon of Mukawa". In 2019, the type species ''Kamuysaurus japonicus'' was named and described by Professor Yoshitsugu Kobayashi, Tomohiro Nishimura, Ryuji Takasaki, Kentaro Chiba, Anthony Ricardo Fiorillo, Kohei Tanaka, Tsogtbaatar Chinzorig, Tamaki Sato and Kazuhiko Sakurai. The generic name is derived from ''kamuy'', meaning "deity" in Ainu, the language of the original inhabitants of Hokkaido. The specific name ''japonicus'', "japanese" in Neola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hadrosaurid
Hadrosaurids (), or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod family, which includes genera such as ''Edmontosaurus'' and ''Parasaurolophus'', was a common group of herbivores during the Late Cretaceous Period. Hadrosaurids are descendants of the Upper Jurassic/Lower Cretaceous iguanodontian dinosaurs and had a similar body layout. Hadrosaurs were among the most dominant herbivores during the Late Cretaceous in Asia and North America, and during the close of the Cretaceous several lineages dispersed into Europe, Africa, South America and Antarctica. Like other ornithischians, hadrosaurids had a predentary bone and a pubic bone which was positioned backwards in the pelvis. Unlike more primitive iguanodonts, the teeth of hadrosaurids are stacked into complex structures known as dental batteries, which acted as effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesodermochelys
''Mesodermochelys'' is an extinct genus of sea turtle known from the Campanian to the Maastrichtian (Late Cretaceous) of what today is Japan.Hirayama R. (2007). "Cranial morphology of ''Mesodermochelys'' (Chelonioidea; Testudines) from the Late Cretaceous of Japan". ''Journal of Vertebrate Paleontology'' 27 (3): 89Aonline, retrieved 28 July 2008/ref> One species is known, the type species ''M. undulatus''; it was given its binomial name by Ren Hirayama and Tsutomu Chitoku in 1996.Hirayama R, Fujii A, Takahashi K. (2006). "A dermochelyid sea turtle from the Upper Cretaceous (Late Campanian) Izumi Group of Shionoe, Takamatsu, Kagawa Prefecture, Western Japan". ''Fossils (Palaeontological Society of Japan)'' 80: 17-20online, retrieved 28 July 2008/ref> Studies of its skull indicate that it was a primitive member of the Dermochelyidae (leatherback turtle family) that was closely related to the Protostegidae. It has been described as the best representative of Mesozoic dermochelyids. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorosaurus
''Phosphorosaurus'' ("phosphate lizard") is an extinct genus of marine lizard belonging to the mosasaur family. ''Phosphorosaurus'' is classified within the Halisaurinae subfamily alongside the genera '' Pluridens'', ''Eonatator'' and ''Halisaurus''. Stratigraphically, ''Phosphorosaurus'' only occurs in the Maastrichtian stage of the Late Cretaceous. Although treated as synonymous with ''Halisaurus'' in the past, recent studies recognize it as valid. Two species are known, ''Phosphorosaurus ortliebi'' from the Craie de Ciply Formation in Belgium, and ''P. ponpetelegans'' from the Hakobuchi Formation of Hokkaido in Japan. ''P. ponpetelegans'' is only known from the very earliest Maastrichtian, whilst ''P. ortliebi'' occurs throughout the Maastrichtian. Description With a length of around 3 m (10 ft), ''Phosphorosaurus'' was small compared to most other mosasaurs, but rather standard in size for a halisaurine. Analysis of ''Phosphorosaurus'' biology suggests that thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosasaurus Hobetsuensis
''Mosasaurus'' (; "lizard of the Meuse River") is the type genus (defining example) of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian stages of the Late Cretaceous. The earliest fossils of ''Mosasaurus'' known to science were found as skulls in a chalk quarry near the Dutch city of Maastricht in the late 18th century, which were initially thought to have been the bones of crocodiles or whales. One skull discovered around 1780, and which was seized by France during the French Revolutionary Wars for its scientific value, was famously nicknamed the "great animal of Maastricht". In 1808, naturalist Georges Cuvier concluded that it belonged to a giant marine lizard with similarities to monitor lizards but otherwise unlike any known living animal. This concept was revolutionary at the time and helped support the then-developing ideas of extinction. Cuvier did not designate a scienti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosasaur
Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Ancient Greek, Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes. Mosasaurs probably evolved from an extinct group of aquatic lizards known as Aigialosauridae, aigialosaurs in the Late Cretaceous, Earliest Late Cretaceous with 42 described genera. During the last 20 million years of the Cretaceous period (Turonian–Maastrichtian ages), with the extinction of the ichthyosaurs and Pliosauridae, pliosaurs, mosasaurs became the dominant marine predators. They themselves became extinct as a result of the Cretaceous–Paleogene extinction event, K-Pg event at the end of the Cretaceous period, about 66 million years ago. Description Mosasaurs breathed air, were powerful swimmers, and were well-adapted to livi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continental Shelf
A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island is known as an ''insular shelf''. The continental margin, between the continental shelf and the abyssal plain, comprises a steep continental slope, surrounded by the flatter continental rise, in which sediment from the continent above cascades down the slope and accumulates as a pile of sediment at the base of the slope. Extending as far as 500 km (310 mi) from the slope, it consists of thick sediments deposited by turbidity currents from the shelf and slope. The continental rise's gradient is intermediate between the gradients of the slope and the shelf. Under the United Nations Convention on the Law of the Sea, the name continental shelf was given a legal definition as the stretch of the seabed adjacent to the sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuffite
Tuffite is a tuff containing both pyroclastic and detrital materials, but predominantly pyroclasts. According to IUGS definition tuffite contains 75 to 25% volcanic (epiclastic) material. There are several classifications that define tuffite. The classification present in the IUGS recommendation are based on the definition established by Schmid (1981). Shvetsov defined tuffites as rocks containing 50 to 90% of the volcanic fragments. Tuffite should therefore contain more than half of volcanic material. If rock contains more than 75 to 90% of pyroclastic material it is referred to as tuff. Some other, mostly older sources state that tuffite may contain 10 to 50% volcanic material. (in Czech) The adjective ''tuffitic'' is used for sediments containing less than 25% volcanic fragments. A tuffite consists of angular and/or rounded fragments of effusive rocks and their minerals, also may contain volcanic ash, pumice and clay minerals. Nonvolcanic material may consist of terrig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudstone
Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, W. H. Freeman, 2nd ed, 529 pp. The term ''mudstone'' is also used to describe carbonate rocks ( limestone or dolomite) that are composed predominantly of carbonate mud. However, in most contexts, the term refers to siliciclastic mudstone, composed mostly of silicate minerals. The NASA Curiosity rover has found deposits of mudstone on Mars that contain organic substances such as propane, benzene and toluene. Definition There is not a single definition of mudstone that has gained general acceptance,Boggs 2006, p.143 though there is wide agreement that mudstones are fine-grained sedimentary rocks, composed mostly of silicate grains with a grain size less than . Individual grains this size are too small to be distin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coal
Coal is a combustible black or brownish-black sedimentary rock, formed as stratum, rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian (geology), Pennsylvanian) and Permian times. Many significant coal deposits are younger than this and originate from the Mesozoic and Cenozoic eras. Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution. With the invention of the steam engine, coal consumption increased. In 2020, coal supplied about a quarter of the world's primary energ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
