Information AboutLimestone |
| CATEGORIES ABOUT LIMESTONE | |
| sedimentary rocks | |
| limestonesedimentary rocks | |
| limestone | |
| stone | |
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is a variety of limestone]] Limestone is a in the form of Chert or Flint , as well as varying amounts of Clay , Silt and Sand as disseminations, nodules, or layers within the rock. The primary source of the calcite in limestone is most commonly Marine Organisms . These organisms secrete shells that settle out of the water column and are deposited on Ocean floors as Pelagic ooze or alternatively is conglomerated in a coral reef (see Lysocline for information on calcite dissolution). Secondary calcite may also be deposited by Supersaturated Meteoric waters ( Groundwater that Precipitates the material in Cave s). This produces Speleothem s such as Stalagmite s and Stalactite s. Another form taken by calcite is that of Oolite s (oolitic limestone) which can be recognized by its granular appearance. Limestone makes up about 10% of the total volume of all sedimentary rocks . Calcite can be either Dissolve d by groundwater or Precipitate d by groundwater, depending on several factors including the water temperature, PH , and dissolved Ion concentrations. Calcite exhibits an unusual characteristic called Retrograde Solubility in which it becomes less soluble in water as the temperature increases. When conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together or it can fill fractures. Karst Topography and Cave s develop in carbonate rocks due to their Solubility in dilute Acid ic Groundwater . Cooling groundwater or mixing of different groundwaters will also create conditions suitable for cave formation. Coastal limestones are often eroded by organisms which bore into the rock by various means. This process is known as Bioerosion . It is most common in the tropics, and it is known throughout the Fossil Record (see Taylor and Wilson, 2003). limestone exposed in central Kentucky , USA. The less-resistant and thinner beds are composed of shale]] Pure limestone is almost white. Because of impurities, such as Clay , sand, organic remains, Iron Oxide and other materials, many limestones exhibit different colors, especially on Weathered surfaces. Limestone may be crystalline, clastic, granular, or massive, depending on the method of formation. Crystals of calcite, Quartz , Dolomite or Barite may line small cavities in the rock. Folk and Dunham classifications are used to describe limestones more precisely. Travertine is a banded, compact variety of limestone formed along streams, particularly where there are waterfalls and around Hot or cold springs. Calcium carbonate is deposited where evaporation of the water leaves a solution that is supersaturated with chemical constituents of calcite. Tufa , a porous or cellular variety of travertine, is found near waterfalls. Coquina is a poorly consolidated limestone composed of pieces of Coral or Shell s. During regional Metamorphism that occurs during the mountain building process ( Orogeny ) limestone recrystallizes into Marble . Limestone is a Parent Material of Mollisol Soil group. LIMESTONE LANDSCAPE See Also: Karst topography Limestone is partially soluble, especially in Acid , and therefore forms many Erosion al Landform s. These include Limestone Pavement s, Pot Hole s, Cenote s, Cave s and Gorge s. Such erosion landscapes are known as karsts. Limestone is less Resistant than most Igneous rocks, but more resistant than most other Sedimentary Rocks . Limestone is therefore usually associated with hills and downland and occurs in regions with other sedimentary rocks, typically Clay s. Bands of limestone emerge from the Earth 's surface in often spectacular rocky outcrops and Island s. Examples include the Burren in Co. Clare, Ireland; the Verdon Gorge in France ; Malham Cove in North Yorkshire and the Isle Of Wight 1, England ; on Fårö near the Swedish island of Gotland , the Niagara Escarpment in Canada / USA , Notch Peak in Utah , and the Ha Long Bay National Park in Vietnam . Unique habitats are found on Alvar s, extremely level expanses of limestone with thin soil mantles. The largest such expanse in Europe is the Stora Alvaret on the island of Oland , Sweden . Huge quarries in northwestern Europe, such as those of Mount Saint Peter (Belgium/Netherlands), extend for more than a hundred kilometers. USES OF LIMESTONE ]] Limestone is especially popular in Architecture , and many landmarks around the world, especially in North America and Europe , are made primarily of the material. So many buildings in Kingston, Ontario, Canada were constructed from it that it is nicknamed the 'Limestone City'. Limestone is readily available and relatively easy to cut into blocks or more elaborate carving. It is also long-lasting and stands up well to exposure. However, it is a very heavy material, making it impractical for tall buildings. It is also quite expensive. Limestone was most popular in the early 20th and late 19th centuries. Train Station s, Bank s and other structures from that era are normally made of limestone. Limestone is used as a facade on some Skyscraper s, but only in thin plates for covering rather than solid blocks. In the United States, Indiana , most notably the Bloomington area, has long been a source of high quality quarried limestone, called Indiana Limestone . Many famous buildings in London are built from Portland Limestone . Limestone was also a very popular building block in the Middle Ages in the areas where it occurred since it is hard, durable, and commonly occurs in easily accessible surface exposures. Many medieval churches and castles in Europe are made of limestone. Beer Stone was a popular kind of limestone for medieval buildings in southern England. in Bavaria is prepared for a Lithography print]] Limestone and marble are very reactive to acid solutions, making Acid Rain a significant problem. Many limestone statues and building surfaces have suffered severe damage due to acid rain. Acid-based cleaning chemicals can also etch limestone, which should only be cleaned with a neutral or mild alkaline-based cleaner. Other uses include:
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