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Conway Formation
The Conway Formation is a Campanian to Danian geologic formation in the South Island of New Zealand and therefore crosses the Cretaceous–Paleogene boundary. Plesiosaur remains are among the fossils that have been recovered from its strata. The Conway Formation is part of the Eyre Group and Haerenga Supergroup. Fossil content Among others, the following fossils have been found in the formation: at .org * '''' * '' Onchopristis d ... [...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 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 Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onchopristis
''Onchopristis'' is an extinct genus of sclerorhynchoid from the Cretaceous of North Africa, Europe, and North America. Its name is derived from the Ancient Greek ''ónkos'' ( ὄγκος, 'barb') and ''prístis'' ( πρίστις, 'saw' or 'sawfish'). It contains two valid species, ''O. numida'' and ''O. dunklei''. ''Onchopristis'' first appeared in the Barremian and its latest occurrence dates to the Campanian, making it one of the oldest and longest-lived sclerorhynchoid genera. Description Specimens of ''O. numida'', IPUW 353500 and IGR 2818, suggest a length estimate of and , respectively; such individuals would have weighed . Like other sclerorhynchoids, it had a long rostrum with large denticles similar to sawfishes and sawsharks. This feature was convergently evolved and its closest living relatives are actually skates. Isolated rostral denticles are the most common fossils of ''Onchopristis'', but rostra, chondrocrania, jaws, oral teeth, vertebrae, and dermal den ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossiliferous Stratigraphic Units Of Oceania
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siltstone Formations
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, pp.381-382 Although its permeability and porosity is relatively low, siltstone is sometimes a tight gas reservoir rock, an unconventional reservoir for natural gas that requires hydraulic fracturing for economic gas production. Siltstone was prized in ancient Egypt for manufacturing statuary and cosmetic palettes. The siltstone quarried at Wadi Hammamat was a hard, fine-grained siltstone that resisted flaking and was almost ideal for such uses. Description There is not complete agreement on the definition of siltstone. One definition is that siltstone is mudrock ( clastic sedimentary rock containing at least 50% clay and silt) in which at least 2/3 of the clay and silt fraction is composed of silt-sized particles. Silt is defined as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone Formations
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topography, topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porosity, porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maastrichtian Stage
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from . The Maastrichtian was preceded by the Campanian and succeeded by the Danian (part of the Paleogene and Paleocene). The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary extinction event) occurred at the end of this age. In this mass extinction, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser-known groups, died out. The cause of the extinction is most commonly linked to an asteroid about wide colliding with Earth, ending the Cretaceous. Stratigraphic definitions Definition The Maastrichtian was introduced into scientific literature by Belgian geologist André Hubert Dumont in 1849, after studying rock strata of the Chalk Group clo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campanian Stage
The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian spans the time from 83.6 (± 0.2) to 72.1 (± 0.2) million years ago. It is preceded by the Santonian and it is followed by the Maastrichtian. The Campanian was an age when a worldwide sea level rise covered many coastal areas. The morphology of some of these areas has been preserved: it is an unconformity beneath a cover of marine sedimentary rocks. Etymology The Campanian was introduced in scientific literature by Henri Coquand in 1857. It is named after the French village of Champagne in the department of Charente-Maritime. The original type locality was a series of outcrop near the village of Aubeterre-sur-Dronne in the same region. Definition The base of the Campanian Stage is defined as a place in the stratigraphic column where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous System Of Oceania
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Formations Of New Zealand
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology, and so is treated as one major aspect of integrated Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface, and the processes that have shaped that structure. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks. By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, and also to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, and the Earth's past climates. Geologists broadly study the properties and processes of Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Polar Region Of The Cretaceous
The South Polar region of the Cretaceous comprised the continent of East Gondwana–modern day Australia 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 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 South Polar region housed many endemic species, including several relict forms that had gone e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratigraphy Of New Zealand
This is a list of the units into which the rock succession of New Zealand is formally divided. As new geological relationships have been discovered new names have been proposed and others are made obsolete. Not all these changes have been universally adopted. This table is based on the 2014 New Zealand Stratigraphic Lexicon (Litho2014). However, obsolete names that are still in use and names postdating the lexicon are included if it aids in understanding. Names for particular rock units have two parts, a proper name which is almost always a geographic location where the rock is found and a hierarchical rank (e.g. Waitematā Group). This ranking system starts with individual 'beds' of rock which can be grouped into 'members', members are grouped into 'formations', formations into 'subgroups' then 'groups'. In New Zealand, groups are further combined into 'supergroups' or for basement rocks into terranes. Not all of these hierarchical layers are necessarily present within a part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Canterbury, New Zealand
Canterbury in New Zealand is the portion of the South Island to the east of the Southern Alps / Kā Tiritiri o te Moana, from the Waiau Uwha River in the north, to the Waitaki River in the south (this is smaller than the area administered by Environment Canterbury). To the west of the Southern Alps lies the Alpine Fault, a major fault boundary, that passes through the South Island from Fiordland in the south, to the Marlborough Region in the north, where it divides into multiple faults. The Pacific Plate lies to the east of the Alpine Fault and the Australian Plate lies to the west. The Pacific Plate is sliding SSW at about 35mm/yr, relative to the Australian Plate, and rising up 10mm/yr, generating the Southern Alps. The Alpine Fault did not develop until early Miocene times (23 Ma). Ten million years ago the Southern Alps were low hills, and they only became mountainous as recently as 5 million years ago. To the east of the Southern Alps are the Canterbury Plains, formed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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