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Portland Limestone
Portland stone is a limestone from the Tithonian stage of the Jurassic period quarried on the Isle of Portland, Dorset. The quarries are cut in beds of white-grey limestone separated by chert beds. It has been used extensively as a building stone throughout the British Isles, notably in major public buildings in London such as St Paul's Cathedral and Buckingham Palace. Portland Stone is also exported to many countries—being used for example in the United Nations headquarters in New York City. Geology Portland Stone formed in a marine environment, on the floor of a shallow, warm, sub-tropical sea probably near land (as evidenced by fossilized driftwood, which is not uncommon). When seawater is warmed by the sun, its capacity to hold dissolved gas is reduced; consequently, dissolved carbon dioxide (CO2) is released into the atmosphere as a gas. Calcium and bicarbonate ions within the water are then able to combine, to form calcium carbonate (CaCO3) as a precipitate. The proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portland Brownstone Quarries
The Portland Brownstone Quarries are a set of historic quarry, quarries in Portland, Connecticut. The brownstone mined from these quarries was an important source for construction in the latter half of the 19th century. The stone from these quarries was used in a number of landmark buildings in Chicago, Boston, New York City, Philadelphia, Baltimore, Washington, D.C., New Haven, Connecticut, and Hartford. The site was listed as a National Historic Landmark, which also placed it on the National Register of Historic Places, on May 16, 2000.Dr. Joanne Kluessendorf (undated) , National Park Service and Early history of the quarry Quarrying on this site began in 1690 by James Stanclift, who contracted with the town of Middletown, Connecticut, Middletown to build stonework in exchange for a deed of land. Commercial quarrying started in 1783 when the Brainerd Quarry Company began operations. During the peak of the brownstone era, more than 1500 workers were employed by the quarrie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic
The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic Magmatic Province. The beginning of the Toarcian Stage started around 183 million years ago and is marked by an extinction event associated with widespread oceanic anoxia, ocean acidification, and elevated temperatures likely caused by the eruption of the Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear boundary with the Cretaceous and is the only boundary between geological periods to remain formally undefined. By the beginning of the Juras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrite
Micrite is a limestone constituent formed of calcareous particles ranging in diameter up to four μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a micron, is a unit of length in the International System of Uni ... formed by the recrystallization of lime mud. Flügel, Erik, ''Microfacies of Carbonate Rocks: Analysis, Interpretation and Application,'' Springer, pp 74-94, 2004 The term was coined in 1959 by Robert Folk for his carbonate rock classification system. Micrite is derived from MICRocrystalline calcITE. In the Folk classification micrite is a carbonate rock dominated by fine-grained calcite. Carbonate rocks that contain fine-grained calcite in addition to allochems are named ''intramicrite'', ''oomicrite'', ''biomicrite'' or ''pelmicrite'' under the Folk classification depending on the dominant allochem. Micrite is lime mud, ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at temperatures exceeding 300 °C, and vaterite is even less stable. Etymology Calcite is derived from the German ''Calcit'', a term from the 19th century that came from the Latin word for lime, ''calx'' (genitive calcis) with the suffix "-ite" used to name minerals. It is thus etymologically related to chalk. When applied by archaeologists and stone trade professionals, the term alabaster is used not just as in geology and mineralogy, where it is res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin ''calx'' " lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in food ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. It is a trace gas in Earth's atmosphere at 421 parts per million (ppm), or about 0.04% by volume (as of May 2022), having risen from pre-industrial levels of 280 ppm. Burning fossil fuels is the primary cause of these increased CO2 concentrations and also the primary cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA Carbon dioxide is soluble in water and is found in groundwater, lakes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Nations Headquarters
zh, 联合国总部大楼french: Siège des Nations uniesrussian: Штаб-квартира Организации Объединённых Наций es, Sede de las Naciones Unidas , image = Midtown Manhattan Skyline 004.jpg , image_size = 400px , caption = Viewed across the East River from Roosevelt Island in 2021; from left to right: the Secretariat, Conference, and General Assembly buildings. In the background (from left to right) are the Empire State Building, the Chrysler Building, One Vanderbilt, and other skyscrapers. , location = , address = 760 United Nations Plaza,Manhattan, New York City, New York ( 10017-6818),United States , coordinates = , start_date = , completion_date = , inauguration_date = , architect = Board of designers mediated by Harrison & Abramovitz , owner = United Nations , cost = $65 million ($ adjusted for inflation) , floor_count = 39 , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buckingham Palace
Buckingham Palace () is a London royal residence and the administrative headquarters of the monarch of the United Kingdom. Located in the City of Westminster, the palace is often at the centre of state occasions and royal hospitality. It has been a focal point for the British people at times of national rejoicing and mourning. Originally known as ''Buckingham House'', the building at the core of today's palace was a large townhouse built for the Duke of Buckingham in 1703 on a site that had been in private ownership for at least 150 years. It was acquired by King George III in 1761 as a private residence for Queen Charlotte and became known as The Queen's House. During the 19th century it was enlarged by architects John Nash and Edward Blore, who constructed three wings around a central courtyard. Buckingham Palace became the London residence of the British monarch on the accession of Queen Victoria in 1837. The last major structural additions were made in the late 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
St Paul's Cathedral
St Paul's Cathedral is an Anglicanism, Anglican cathedral in London and is the seat of the Bishop of London. The cathedral serves as the mother church of the Diocese of London. It is on Ludgate Hill at the highest point of the City of London and is a Listed Building, Grade I listed building. Its dedication to Paul the Apostle dates back to the original church on this site, founded in AD 604. The present structure, dating from the late 17th century, was designed in the English Baroque style by Sir Christopher Wren. Its construction, completed in Wren's lifetime, was part of a major rebuilding programme in the city after the Great Fire of London. The earlier Gothic cathedral (Old St Paul's Cathedral), largely destroyed in the Great Fire, was a central focus for medieval and early modern London, including Paul's walk and St Paul's Churchyard, being the site of St Paul's Cross. The cathedral is one of the most famous and recognisable sights of London. Its dome, surrounded by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, and over six thousand smaller islands."British Isles", '' Encyclopædia Britannica''. They have a total area of and a combined population of almost 72 million, and include two sovereign states, the Republic of Ireland (which covers roughly five-sixths of Ireland), and the United Kingdom of Great Britain and Northern Ireland. The Channel Islands, off the north coast of France, are normally taken to be part of the British Isles, even though they do not form part of the archipelago. The oldest rocks are 2.7 billion years old and are found in Ireland, Wales and the northwest of Scotland. During the Silurian period, the north-western regions collided with the south-east, which had been part of a separate continental landmass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chert
Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a chemical precipitate or a diagenetic replacement, as in petrified wood. Chert is typically composed of the petrified remains of siliceous ooze, the biogenic sediment that covers large areas of the deep ocean floor, and which contains the silicon skeletal remains of diatoms, silicoflagellates, and radiolarians. Precambrian cherts are notable for the presence of fossil cyanobacteria. In addition to microfossils, chert occasionally contains macrofossils. However, some chert is devoid of any fossils. Chert varies greatly in color (from white to black), but most often manifests as gray, brown, grayish brown and light green to rusty redW.L. Roberts, T.J. Campbell, G.R. Rapp Jr., "Encyclopedia of Mineralogy, Second Edition", 1990. R.S. Mit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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