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Oolitic Aragonite Sand
Oolitic aragonite sand is composed of the calcium carbonate mineral, aragonite, with an egg-like shape (" oolitic" from the Ancient Greek word ᾠόν for "egg") and sand grain size. This sand type forms in tropical waters through precipitation, sedimentation, and microbial activity, and is indicative of high energy environments. The production of oolitic aragonite sand in the Bahamas surpasses anyplace else in the world. Changes in seawater chemistry and paleoenvironments can be interpreted by the sand's chemical composition and structure. Formation Oolitic aragonite sand forms in high-salinity waters that are turbulent, shallow, and warm. The sand starts to form around a nucleus of calcium carbonate, such as a peloid, shell fragment, or foraminifer. The nucleus is coated with a thin layer of crystalline carbonate to form the cortex of the ooid. Compared to other types of sand formation that involve the weathering and erosion of a larger rock by turbulent waters, oolitic arago ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraminifera
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and other uses; and commonly an external shell (called a "Test (biology), test") of diverse forms and materials. Tests of chitin (found in some simple genera, and Textularia in particular) are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthos, benthic), while a smaller number float in the water column at various depths (i.e., are planktonic), which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA. Foraminifera typically produce a test (biology), test, or shell, which can have eithe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Types Of Limestone
This is a list of types of limestone arranged according to location. It includes both formal stratigraphic unit names and less formal designations. Africa Egypt *Tura limestone, used for the Great Pyramid casing stones *Mokattam limestone; Great Pyramid core stones and head of the Great Sphinx are of the "Member III" stratum * Galala marble (a type of limestone, not a true marble) Asia India * * Israel (West Bank) * * Europe Austria * Belgium *, (not a "true marble"; Devonian limestone) * * Croatia * France * *, or "Paris stone" (city buildings are widely faced with it) **, or Oise, limestone (variety of Lutetian) * *, in the Loire Valley Germany * * Gibraltar * Ireland * , not a "true marble"; fossiliferous Carboniferous limestone. Italy * , not a "true marble"; fossiliferous limestone United Kingdom England: * (not a "true marble"; Carboniferous limestone) * * * , the famous London Stone is made of this. * (not a "true slate"; thin-bedded limestone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Salt Lake
The Great Salt Lake is the largest saltwater lake in the Western Hemisphere and the eighth-largest terminal lake in the world. It lies in the northern part of the U.S. state of Utah and has a substantial impact upon the local climate, particularly through lake-effect snow. It is a remnant of Lake Bonneville, a prehistoric body of water that covered much of western Utah. The area of the lake can fluctuate substantially due to its low average depth of . In the 1980s, it reached a historic high of , and the West Desert Pumping Project was established to mitigate flooding by pumping water from the lake into the nearby desert. In 2021, after years of sustained drought and increased water diversion upstream of the lake, it fell to its lowest recorded area at 950 square miles (2,460 km²), falling below the previous low set in 1963. Continued shrinkage could turn the lake into a bowl of toxic dust, poisoning the air around Salt Lake City. The lake's three major tributaries, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
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 b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bahama Banks
The Bahama Banks are the submerged carbonate platforms that make up much of the Bahama Archipelago. The term is usually applied in referring to either the Great Bahama Bank around Andros Island, or the Little Bahama Bank of Grand Bahama Island and Great Abaco, which are the largest of the platforms, and the Cay Sal Bank north of Cuba. The islands of these banks are politically part of the Bahamas. Other banks are the three banks of the Turks and Caicos Islands, namely the Caicos Bank of the Caicos Islands, the bank of the Turks Islands, and wholly submerged Mouchoir Bank. Farther southeast are the equally wholly submerged Silver Bank and Navidad Bank north of the Dominican Republic. Geologic history and structure The limestone that comprises the Banks has been accumulating since at least the Cretaceous period, and perhaps as early as the Jurassic; today the total thickness under the Great Bahama Bank is over 4.5 kilometres (2.8 miles). As the limestone was deposited in sha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Bahamas
The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to 88% of the archipelago's population. The archipelagic state consists of more than 3,000 islands, cays, and islets in the Atlantic Ocean, and is located north of Cuba and northwest of the island of Hispaniola (split between the Dominican Republic and Haiti) and the Turks and Caicos Islands, southeast of the U.S. state of Florida, and east of the Florida Keys. The capital is Nassau, Bahamas, Nassau on the island of New Providence. The Royal Bahamas Defence Force describes The Bahamas' territory as encompassing of ocean space. The Bahama Islands were inhabited by the Lucayan people, Lucayans, a branch of the Arawakan-Taino language, speaking TaÃno, for many centuries. Christopher Columbus was the first European to see the islands, making hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomineralization
Biomineralization, also written biomineralisation, is the process by which living organisms produce minerals, often to harden or stiffen existing tissues. Such tissues are called mineralized tissues. It is an extremely widespread phenomenon; all six taxonomic kingdoms contain members that are able to form minerals, and over 60 different minerals have been identified in organisms. Examples include silicates in algae and diatoms, carbonates in invertebrates, and calcium phosphates and carbonates in vertebrates. These minerals often form structural features such as sea shells and the bone in mammals and birds. Organisms have been producing mineralized skeletons for the past 550 million years. Calcium carbonates and calcium phosphates are usually crystalline, but silica organisms (sponges, diatoms...) are always non crystalline minerals. Other examples include copper, iron and gold deposits involving bacteria. Biologically formed minerals often have special uses such as magnetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ooid
Ooids are small (commonly ≤2 mm in diameter), spheroidal, "coated" (layered) sedimentary grains, usually composed of calcium carbonate, but sometimes made up of iron- or phosphate-based minerals. Ooids usually form on the sea floor, most commonly in shallow tropical seas (around the Bahamas, for example, or in the Persian Gulf). After being buried under additional sediment, these ooid grains can be cemented together to form a sedimentary rock called an ''oolite''. Oolites usually consist of calcium carbonate; these belong to the limestone rock family. Pisoids are similar to ooids, but are larger than 2 mm in diameter, often considerably larger, as with the pisoids in the hot springs at Carlsbad (Karlovy Vary) in the Czech Republic. Formation An ooid forms as a series of concentric layers around a nucleus. The layers contain crystals arranged radially, tangentially or randomly. The nucleus can be a shell fragment, quartz grain or any other small fragment. Most mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peloid
Peloid is mud, or clay used therapeutically, as part of balneotherapy, or therapeutic bathing. Peloids consist of humus and minerals formed over many years by geological and biological, chemical and physical processes. Numerous peloids are available today, of which the most popular are peat pulps, various medicinal clays, mined in various locations around the world, and a variety of plant substances. Also, health spas often use locally available lake and sea muds and clays. Peloid procedures are also various; the most common of them are ''peloid wraps'', ''peloid baths'', and ''peloid packs'' applied locally to the part of the body, which is being treated. Peloid packs and, specifically, peat, have been used in Europe for medicinal baths and wraps for the past 200 years. Peloid preparation varies in different spas. Typically, peloids are matured for a period of up to 2 years in special ponds. The majority of spas ... use artificial ponds where the natural ("virgin") clay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aragonite
Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including precipitation from marine and freshwater environments. The crystal lattice of aragonite differs from that of calcite, resulting in a different crystal shape, an orthorhombic crystal system with acicular crystal. Repeated twinning results in pseudo-hexagonal forms. Aragonite may be columnar or fibrous, occasionally in branching helictitic forms called ''flos-ferri'' ("flowers of iron") from their association with the ores at the Carinthian iron mines. Occurrence The type location for aragonite is Molina de Aragón in the Province of Guadalajara in Castilla-La Mancha, Spain, for which it was named in 1797. Aragonite is found in this locality as cyclic twins inside gypsum and marls of the Keuper facies of the Triassic. This type of arago ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
