1.
Red Lake (Croatia)
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Red Lake is a sinkhole containing a karst lake near the city of Imotski, Croatia. It is known for its numerous caves and remarkably high cliffs, reaching over 241 metres above water level. The total explored depth of this sinkhole is approximately 530 metres with a volume of roughly 25–30 million cubic meters, water drains out of the basin through underground waterways that descend below the level of the lake floor. The sinkhole is named after the color of the surrounding cliffs. Like the nearby Blue Lake, it is presumed that the lake emerged when the ceiling of a large cave hall collapsed, the lake is a habitat of the fish Delminichthys adspersus. In the dry period of the year, this fish can be seen in surrounding springs, rivers and lakes. At the 13th International Congress of Speleology, new findings were revealed, an inflow cave-shaped canal that measured approximately 30 x 30 meters was discovered in the eastern part of the lake at a depth of 175 meters. Media related to Red Lake, Croatia at Wikimedia Commons Stamp by Croatian post
2.
Croatia
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Croatia, officially the Republic of Croatia, is a sovereign state between Central Europe, Southeast Europe, and the Mediterranean. Its capital city is Zagreb, which one of the countrys primary subdivisions. Croatia covers 56,594 square kilometres and has diverse, mostly continental, Croatias Adriatic Sea coast contains more than a thousand islands. The countrys population is 4.28 million, most of whom are Croats, the Croats arrived in the area of present-day Croatia during the early part of the 7th century AD. They organised the state into two duchies by the 9th century, tomislav became the first king by 925, elevating Croatia to the status of a kingdom. The Kingdom of Croatia retained its sovereignty for nearly two centuries, reaching its peak during the rule of Kings Petar Krešimir IV and Dmitar Zvonimir, Croatia entered a personal union with Hungary in 1102. In 1527, faced with Ottoman conquest, the Croatian Parliament elected Ferdinand I of the House of Habsburg to the Croatian throne. In 1918, after World War I, Croatia was included in the unrecognized State of Slovenes, Croats and Serbs which seceded from Austria-Hungary, a fascist Croatian puppet state backed by Fascist Italy and Nazi Germany existed during World War II. After the war, Croatia became a member and a federal constituent of the Socialist Federal Republic of Yugoslavia. On 25 June 1991 Croatia declared independence, which came wholly into effect on 8 October of the same year, the Croatian War of Independence was fought successfully during the four years following the declaration. A unitary state, Croatia is a republic governed under a parliamentary system, the International Monetary Fund classified Croatia as an emerging and developing economy, and the World Bank identified it as a high-income economy. Croatia is a member of the European Union, United Nations, the Council of Europe, NATO, the World Trade Organization, the service sector dominates Croatias economy, followed by the industrial sector and agriculture. Tourism is a significant source of revenue during the summer, with Croatia ranked the 18th most popular tourist destination in the world, the state controls a part of the economy, with substantial government expenditure. The European Union is Croatias most important trading partner, since 2000, the Croatian government constantly invests in infrastructure, especially transport routes and facilities along the Pan-European corridors. Internal sources produce a significant portion of energy in Croatia, the rest is imported, the origin of the name is uncertain, but is thought to be a Gothic or Indo-Aryan term assigned to a Slavic tribe. The oldest preserved record of the Croatian ethnonym *xъrvatъ is of variable stem, the first attestation of the Latin term is attributed to a charter of Duke Trpimir from the year 852. The original is lost, and just a 1568 copy is preserved—leading to doubts over the authenticity of the claim, the oldest preserved stone inscription is the 9th-century Branimir Inscription, where Duke Branimir is styled as Dux Cruatorvm. The inscription is not believed to be dated accurately, but is likely to be from during the period of 879–892, the area known as Croatia today was inhabited throughout the prehistoric period
3.
Karst
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Karst topography is a landscape formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves and it has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes, the English word karst was borrowed from German Karst in the late 19th century. The German word came into use before the 19th century, according to the prevalent interpretation, the term is derived from the German name for the Karst region, a limestone plateau above the city of Trieste in the northern Adriatic. Scholars disagree, however, on whether the German word was borrowed from Slovene, the Slovene common noun kras was first attested in the 18th century, and the adjective form kraški in the 16th century. The Slovene words arose through metathesis from the reconstructed form *korsъ, ultimately, the word is of Mediterranean origin, believed to derive from some Romanized Illyrian base. It has been suggested that the word may derive from the Proto-Indo-European root karra- rock, the name may also be connected to the oronym Karsádios oros cited by Ptolemy, and perhaps also to Latin Carusardius. The development of karst occurs whenever acidic water starts to break down the surface of bedrock near its cracks, as the bedrock continues to degrade, its cracks tend to get bigger. As time goes on, these fractures will become wider, if this underground drainage system does form, it will speed up the development of karst formations there because more water will be able to flow through the region, giving it more erosive power. The carbonic acid that causes karstic features is formed as rain passes through the atmosphere picking up carbon dioxide, once the rain reaches the ground, it may pass through soil that can provide much more CO2 to form a weak carbonic acid solution, which dissolves calcium carbonate. The oxidation of sulfides leading to the formation of acid can also be one of the corrosion factors in karst formation. As oxygen -rich surface waters seep into deep anoxic karst systems, they bring oxygen, sulfuric acid then reacts with calcium carbonate, causing increased erosion within the limestone formation. This chain of reactions is, This reaction chain forms gypsum, the karstification of a landscape may result in a variety of large- or small-scale features both on the surface and beneath. On exposed surfaces, small features may include solution flutes, runnels, limestone pavement, medium-sized surface features may include sinkholes or cenotes, vertical shafts, foibe, disappearing streams, and reappearing springs. Large-scale features may include limestone pavements, poljes, and karst valleys, mature karst landscapes, where more bedrock has been removed than remains, may result in karst towers, or haystack/eggbox landscapes. Beneath the surface, complex underground systems and extensive caves. Some of the most dramatic of these formations can be seen in Thailands Phangnga Bay, calcium carbonate dissolved into water may precipitate out where the water discharges some of its dissolved carbon dioxide. Rivers which emerge from springs may produce tufa terraces, consisting of layers of calcite deposited over extended periods of time, in caves, a variety of features collectively called speleothems are formed by deposition of calcium carbonate and other dissolved minerals
4.
Carbonate rocks
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Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite and dolostone, which is composed of the mineral dolomite. Calcite can be dissolved by groundwater or precipitated by groundwater, depending on several factors including the water temperature, pH. Calcite exhibits a 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 caves develop in carbonate rocks because of their solubility in dilute acidic groundwater. Cooling groundwater or mixing of different groundwaters will also create conditions suitable for cave formation, marble is the metamorphic carbonate rock. Rare igneous carbonate rocks exist as intrusive carbonatites and even rarer volcanic carbonate lava
5.
Suffosion
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Suffosion sinkholes are normally associated with karst topography although they may form in other types of rock including chalk, gypsum and basalt. In the karst of the UKs Yorkshire Dales, numerous surface depressions known locally as shakeholes, are the result of glacial till washing into fissures in the underlying limestone. Suffosion occurs when loose soil, loess, or other non-cohesive material lies on top of a limestone substratum containing fissures, rain and surface water gradually wash this material through these fissures and into caves beneath. Over time, this creates a depression on the landscape of varying depth, the following sites are examples of sinkholes formed by suffosion, Whitepit, south of Priddy, Somerset, UK
6.
Dead Sea
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The Dead Sea, is a salt lake bordered by Jordan to the east and Israel and Palestine to the west. Its surface and shores are 430.5 metres below sea level, the Dead Sea is 304 m deep, the deepest hypersaline lake in the world. With 34. 2% salinity, it is 9.6 times as salty as the ocean and this salinity makes for a harsh environment in which plants and animals cannot flourish, hence its name. The Dead Sea is 50 kilometres long and 15 kilometres wide at its widest point and it lies in the Jordan Rift Valley and its main tributary is the Jordan River. The Dead Sea has attracted visitors from around the Mediterranean basin for thousands of years and it was one of the worlds first health resorts, and it has been the supplier of a wide variety of products, from asphalt for Egyptian mummification to potash for fertilizers. People also use the salt and the minerals from the Dead Sea to create cosmetics, the Dead Sea water has a density of 1.24 kg/litre, which makes swimming similar to floating. The Dead Sea is receding at an alarming rate, multiple canals and pipelines were proposed to reduce its recession, which had begun causing many problems. The Red Sea–Dead Sea Water Conveyance project, carried out by Jordan, will provide water to neighboring countries, the first phase of the project is scheduled to begin in 2018 and be completed in 2021. In Hebrew, the Dead Sea is Yām ha-Melaḥ, meaning sea of salt, the Bible uses this term alongside two others, the Sea of the Arabah, and the Eastern Sea. The designation Dead Sea never appears in the Bible, in prose sometimes the term Yām ha-Māvet is used, due to the scarcity of aquatic life there. In Arabic the Dead Sea is called al-Bahr al-Mayyit, or less commonly baḥrᵘ lūṭᵃ, another historic name in Arabic was the Sea of Zoʼar, after a nearby town in biblical times. The Greeks called it Lake Asphaltites, the Dead Sea is an endorheic lake located in the Jordan Rift Valley, a geographic feature formed by the Dead Sea Transform. This left lateral-moving transform fault lies along the plate boundary between the African Plate and the Arabian Plate. It runs between the East Anatolian Fault zone in Turkey and the end of the Red Sea Rift offshore of the southern tip of Sinai. It is here that the Upper Jordan River/Sea of Galilee/Lower Jordan River water system comes to an end. The Jordan River is the major water source flowing into the Dead Sea, although there are small perennial springs under and around the Dead Sea, forming pools. The Mujib River, biblical Arnon, is one the larger sources of the Dead Sea other than the Jordan. The Wadi Mujib valley,420 m below the sea level in the southern of Jordan valley, is a biosphere reserve, other more substantial sources are Wadi Darajeh /Nahal Dragot, and Nahal Arugot
7.
Gypsum
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Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is widely mined and is used as a fertilizer, and as the constituent in many forms of plaster, blackboard chalk. Mohs scale of hardness, based on scratch Hardness comparison. It forms as a mineral and as a hydration product of anhydrite. The word gypsum is derived from the Greek word γύψος, plaster, because the quarries of the Montmartre district of Paris have long furnished burnt gypsum used for various purposes, this dehydrated gypsum became known as plaster of Paris. Upon addition of water, after a few tens of minutes plaster of Paris becomes regular gypsum again, causing the material to harden or set in ways that are useful for casting, Gypsum was known in Old English as spærstān, spear stone, referring to its crystalline projections. Gypsum may act as a source of sulfur for plant growth, which was discovered by J. M. Mayer, american farmers were so anxious to acquire it that a lively smuggling trade with Nova Scotia evolved, resulting in the so-called Plaster War of 1820. In the 19th century, it was known as lime sulfate or sulfate of lime. Gypsum is moderately water-soluble and, in contrast to most other salts, it exhibits retrograde solubility, when gypsum is heated in air it loses water and converts first to calcium sulfate hemihydrate, and, if heated further, to anhydrous calcium sulfate. As for anhydrite, its solubility in saline solutions and in brines is also dependent on NaCl concentration. Gypsum crystals are found to contain water and hydrogen bonding. Gypsum occurs in nature as flattened and often twinned crystals, and transparent, selenite contains no significant selenium, rather, both substances were named for the ancient Greek word for the Moon. Selenite may also occur in a silky, fibrous form, in case it is commonly called satin spar. Finally, it may also be granular or quite compact, in hand-sized samples, it can be anywhere from transparent to opaque. A very fine-grained white or lightly tinted variety of gypsum, called alabaster, is prized for ornamental work of various sorts, in arid areas, gypsum can occur in a flower-like form, typically opaque, with embedded sand grains called desert rose. It also forms some of the largest crystals found in nature, up to 12 m long, Gypsum is a common mineral, with thick and extensive evaporite beds in association with sedimentary rocks. Deposits are known to occur in strata from as far back as the Archaean eon, Gypsum is deposited from lake and sea water, as well as in hot springs, from volcanic vapors, and sulfate solutions in veins. Hydrothermal anhydrite in veins is commonly hydrated to gypsum by groundwater in near-surface exposures and it is often associated with the minerals halite and sulfur
8.
Drainage
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Drainage is the natural or artificial removal of surface and sub-surface water from an area. The internal drainage of most agricultural soils is good enough to prevent severe waterlogging, all houses in the major cities of Harappa and Mohenjo-daro had access to water and drainage facilities. Waste water was directed to covered drains, which lined the major streets, the invention of hollow-pipe drainage is credited to Sir Hugh Dalrymple, who died in 1753. New drainage systems incorporate geotextile filters that retain and prevent fine grains of soil from passing into, geotextiles are synthetic textile fabrics specially manufactured for civil and environmental engineering applications. Geotextiles are designed to retain fine soil particles while allowing water to pass through, in a typical drainage system they would be laid along a trench which would then be filled with coarse granular material, gravel, sea shells, stone or rock. The geotextile is then folded over the top of the stone, groundwater seeps through the geotextile and flow within the stone to an outfell. In high groundwater conditions a perforated pipe is laid along the base of the drain to increases the volume of water transported in the drain. Alternatively, the prefabricated plastic drainage system made of HDPE called SmartDitch, often incorporating geotextile, over the past 30 years geotextile and PVC filters have become the most commonly used soil filter media. They are cheap to produce and easy to lay, with factory controlled properties that ensure long term filtration performance even in fine silty soil conditions, seattles Public Utilities created a pilot program called Street Edge Alternatives Project. The project focuses on designing a system to provide drainage that more closely mimics the natural landscape prior to development than traditional piped systems, the streets are characterized by ditches along the side of the roadway, with plantings designed throughout the area. An emphasis on non curbed sidewalks allows water to more freely into the areas of permeable surface on the side of the streets. Because of the plantings the run off water from the area does not all directly go into the ground. Sustainable Urban Drainage Systems are designed to encourage contractors to install drainage system that closely mimic the natural flow of water in nature. Since 2010 local and neighbourhood planning in the UK is required by law to factor SUDS into any development projects that they are responsible for, slot drainage has proved the most breakthrough product of the last twenty years as a drainage option. Both stainless steel and concrete channel slot drainage have become industry standards on construction projects, the civil engineer is responsible for drainage in construction projects. They set out from the all the roads, street gutters, drainage, culverts. During the construction process he/she will set out all the levels for each of the previously mentioned factors. Civil engineers and construction managers work alongside architects and supervisors, planners, quantity surveyors, typically, most jurisdictions have some body of drainage law to govern to what degree a landowner can alter the drainage from his parcel
9.
Erosion
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In earth science, erosion is the action of surface processes that remove soil, rock, or dissolved material from one location on the Earths crust, then transport it away to another location. Eroded sediment or solutes may be transported just a few millimetres, the rates at which such processes act control how fast a surface is eroded. Feedbacks are also possible between rates of erosion and the amount of eroded material that is carried by, for example. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, while erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the rate of erosion in the region. Excessive erosion causes both on-site and off-site problems, on-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of bodies, as well as sediment-related damage to roads. Intensive agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion, however, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, and the surface runoff which may result from rainfall, produces four types of soil erosion, splash erosion, sheet erosion, rill erosion. Splash erosion is generally seen as the first and least severe stage in the erosion process. In splash erosion, the impact of a falling raindrop creates a crater in the soil. The distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rate is greater than the rate at which water can infiltrate into the soil. If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope, sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes, generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically of the order of a few centimetres or less and this means that rills exhibit hydraulic physics very different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow
10.
Limestone
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Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate, about 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, most cave systems are through limestone bedrock. The first geologist to distinguish limestone from dolomite was Belsazar Hacquet in 1778, like most other sedimentary rocks, most limestone is composed of grains. Most grains in limestone are skeletal fragments of organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts and these organisms secrete shells made of aragonite or calcite, and leave these shells behind when they die. Limestone often contains variable amounts of silica in the form of chert or siliceous skeletal fragment, some limestones do not consist of grains at all, and are formed completely by the chemical precipitation of calcite or aragonite, i. e. travertine. Secondary calcite may be deposited by supersaturated meteoric waters and this produces speleothems, such as stalagmites and stalactites. Another form taken by calcite is oolitic limestone, which can be recognized by its granular appearance, the primary source of the calcite in limestone is most commonly marine organisms. Some of these organisms can construct mounds of rock known as reefs, below about 3,000 meters, water pressure and temperature conditions cause the dissolution of calcite to increase nonlinearly, so limestone typically does not form in deeper waters. Limestones may also form in lacustrine and evaporite depositional environments, calcite can be dissolved or precipitated by groundwater, depending on several factors, including the water temperature, pH, and dissolved ion concentrations. Calcite exhibits a characteristic called retrograde solubility, in which it becomes less soluble in water as the temperature increases. Impurities will cause limestones to exhibit different colors, especially with 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, when conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together, or it can fill fractures. Travertine is a banded, compact variety of limestone formed along streams, particularly there are waterfalls. Calcium carbonate is deposited where evaporation of the leaves a solution supersaturated with the 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 shells. During regional metamorphism that occurs during the building process, limestone recrystallizes into marble
11.
Percolation
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In physics, chemistry and materials science, percolation refers to the movement and filtering of fluids through porous materials. For example, in geology, percolation refers to filtration of water through soil, the water flows to recharge the groundwater in the water table and aquifers. Statistical physics concepts such as scaling theory, renormalization, phase transition, critical phenomena, combinatorics is commonly employed to study percolation thresholds. Due to the complexity involved in obtaining exact results from analytical models of percolation, the current fastest algorithm for percolation was published in 2000 by Mark Newman and Robert Ziff. Example/theory, A hole is dug in the ground surface, water is filled in to the hole and the time is measured for a drop of one inch in the water surface. If the water surface quickly drops, as seen in poorly-graded sands. If the hydraulic conductivity of the site is low then the site is undesirable, notices of the AMS, May 2006. ISBN 0-7484-0075-3, ISBN 0-7484-0076-1 Geoffrey Grimmett, introduction to Percolation Theory A. Bunde, S. Havlin Fractals and Disordered Systems, Springer,1996 S. Kirkpatrick Percolation and conduction Rev. Mod
12.
Subsidence
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Subsidence is the motion of a surface as it shifts downward relative to a datum such as sea level. The opposite of subsidence is uplift, which results in an increase in elevation, ground subsidence is of concern to geologists, geotechnical engineers and surveyors. Subsidence frequently causes problems in karst terrains, where dissolution of limestone by fluid flow in the subsurface causes the creation of voids. If the roof of these voids becomes too weak, it can collapse and this type of subsidence can result in sinkholes which can be many hundreds of meters deep. Several types of mining, and specifically methods which intentionally cause the extracted void to collapse will result in surface subsidence. Mining-induced subsidence is relatively predictable in its magnitude, manifestation and extent, mining-induced subsidence is nearly always very localized to the surface above the mined area, plus a margin around the outside. Where mining activity is planned, mining-induced subsidence can be successfully managed if there is co-operation from all of the stakeholders and this is accomplished through a combination of careful mine planning, the taking of preventive measures, and the carrying out of repairs post-mining. If natural gas is extracted from a gas field the initial pressure in the field will drop over the years. The gas pressure also supports the soil layers above the field, if the pressure drops, the soil pressure increases and this leads to subsidence at the ground level. Since exploitation of the Slochteren gas field started in the late 1960s the ground level over a 250 km² area has dropped by a current maximum of 30 cm, the Geospatial Information Authority of Japan reported immediate subsidence caused by the 2011 Tōhoku earthquake. In Northern Japan, subsidence of 0.50 m was observed on the coast of the Pacific Ocean in Miyako, Tōhoku, while Rikuzentakata, in the south at Sōma, Fukushima,0.29 m was observed. The maximum amount of subsidence was 1.2 m, coupled with horizontal diastrophism of up to 5.3 m on the Oshika Peninsula in Miyagi Prefecture, the habitation of lowlands, such as coastal or delta plains, requires drainage. The resulting aeration of the leads to the oxidation of its organic components, such as peat. This applies especially when water levels are periodically adapted to subsidence, in order to maintain desired unsaturated zone depths. In addition to this, drained soils consolidate as a result of increased effective stress, in this way, land subsidence has the potential of becoming self-perpetuating, having rates up to 5 cm/yr. Water management used to be tuned primarily to such as crop optimisation but, to varying extents. When differential stresses exist in the Earth, these can be accommodated either by geological faulting in the brittle crust, or by flow in the hotter. Where faults occur, absolute subsidence may occur in the wall of normal faults
13.
Cave
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A cave is a hollow place in the ground, specifically a natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and often extend deep underground, the word cave can also refer to much smaller openings such as sea caves, rock shelters, and grottos. A cavern is a type of cave, naturally formed in soluble rock with the ability to grow speleothems. Speleology is the science of exploration and study of all aspects of caves, visiting or exploring caves for recreation may be called caving, potholing, or spelunking. The formation and development of caves is known as speleogenesis, which can occur over the course of millions of years, caves are formed by various geologic processes and can be variable sizes. These may involve a combination of processes, erosion from water, tectonic forces, microorganisms, pressure. Isotopic dating techniques can be applied to cave sediments, in order to determine the timescale when geologic events may have occurred to help form and it is estimated that the maximum depth of a cave cannot be more than 3,000 metres due to the pressure of overlying rocks. For karst caves the maximum depth is determined on the basis of the limit of karst forming processes. Most caves are formed in limestone by dissolution, solutional caves or karst caves are the most frequently occurring caves and such caves form in rock that is soluble. Most occur in limestone, but they can form in other rocks including chalk, dolomite, marble, salt. Rock is dissolved by acid in groundwater that seeps through bedding planes, faults, joints. Over geological epochs cracks expand to become caves and cave systems, the largest and most abundant solutional caves are located in limestone. Limestone dissolves under the action of rainwater and groundwater charged with H2CO3, the dissolution process produces a distinctive landform known as karst, characterized by sinkholes and underground drainage. Limestone caves are often adorned with calcium carbonate formations produced through slow precipitation and these include flowstones, stalactites, stalagmites, helictites, soda straws and columns. These secondary mineral deposits in caves are called speleothems, the portions of a solutional cave that are below the water table or the local level of the groundwater will be flooded. Lechuguilla Cave in New Mexico and nearby Carlsbad Cavern are now believed to be examples of type of solutional cave. They were formed by H2S gas rising from below, where reservoirs of oil give off sulfurous fumes and this gas mixes with ground water and forms H2SO4. The acid then dissolves the limestone from below, rather than from above, caves formed at the same time as the surrounding rock are called primary caves
14.
Water table
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The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water, the water table is the surface where the water pressure head is equal to the atmospheric pressure. It may be visualized as the surface of the materials that are saturated with groundwater in a given vicinity. The groundwater may be from precipitation or from groundwater flowing into the aquifer, in areas with sufficient precipitation, water infiltrates through pore spaces in the soil, passing through the unsaturated zone. At increasing depths water fills in more of the spaces in the soils. Below the water table, in the zone, layers of permeable rock that yield groundwater are called aquifers. In less permeable soils, such as tight bedrock formations and historic lakebed deposits, the water table should not be confused with the water level in a deeper well. The elevation of the water in this well is dependent upon the pressure in the deeper aquifer and is referred to as the potentiometric surface. The water table may vary due to changes such as precipitation and evapotranspiration. Springs, rivers, lakes and oases occur when the table reaches the surface. Springs commonly form on hillsides, where the Earths slanting surface may intersect with the water table, Groundwater entering rivers and lakes accounts for the base-flow water levels in water bodies. Within an aquifer, the table is rarely horizontal, but reflects the surface relief due to the capillary effect in soils, sediments. In the aquifer, groundwater flows from points of pressure to points of lower pressure. The slope of the table is known as the hydraulic gradient, which depends on the rate at which water is added to and removed from the aquifer. This occurs when there is a layer of rock or sediment or relatively impermeable layer above the main water table/aquifer. If a perched aquifers flow intersects the Earths dry surface, at a wall for example. On low-lying oceanic islands with porous soil, freshwater tends to collect in lenticular pools on top of the denser seawater intruding from the sides of the islands, such an islands freshwater lens, and thus the water table, rises and falls with the tides. In some regions, for example, Great Britain or California, winter precipitation is higher than summer precipitation
15.
Sandstone
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Sandstone is a clastic sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz or feldspar because these are the most common minerals in the Earths crust, like sand, sandstone may be any color, 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 topographic features, quartz-bearing sandstone is converted into quartzite through heating and pressure, usually related to tectonic compression within orogenic belts. They are formed from cemented grains that may either be fragments of a rock or be mono-minerallic crystals. The cements binding these grains together are typically calcite, clays, grain sizes in sands are defined within the range of 0.0625 mm to 2 mm. The formation of sandstone involves two principal stages, first, a layer or layers of sand accumulates as the result of sedimentation, either from water or from air. Typically, sedimentation occurs by the settling out from suspension. The most common cementing materials are silica and calcium carbonate, which are derived either from dissolution or from alteration of the sand after it was buried. Colours will usually be tan or yellow, a predominant additional colourant in the southwestern United States is iron oxide, which imparts reddish tints ranging from pink to dark red, with additional manganese imparting a purplish hue. Red sandstones are seen in the Southwest and West of Britain, as well as central Europe. The regularity of the latter favours use as a source for masonry, either as a building material or as a facing stone. These physical properties allow the grains to survive multiple recycling events. Quartz grains evolve from rock, which are felsic in origin. Feldspathic framework grains are commonly the second most abundant mineral in sandstones, Feldspar can be divided into two smaller subdivisions, alkali feldspars and plagioclase feldspars. The different types of feldspar can be distinguished under a petrographic microscope, below is a description of the different types of feldspar. Alkali feldspar is a group of minerals in which the composition of the mineral can range from KAlSi3O8 to NaAlSi3O8. Plagioclase feldspar is a group of solid solution minerals that range in composition from NaAlSi3O8 to CaAl2Si2O8. Lithic framework grains are pieces of ancient source rock that have yet to weather away to individual mineral grains, accessory minerals are all other mineral grains in a sandstone, commonly these minerals make up just a small percentage of the grains in a sandstone
16.
Papua New Guinea
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Its capital, located along its southeastern coast, is Port Moresby. The western half of New Guinea forms the Indonesian provinces of Papua, Papua New Guinea is one of the most culturally diverse countries in the world. There are 852 known languages in the country, of which 12 have no known living speakers, most of the population of more than 7 million people live in customary communities, which are as diverse as the languages. It is also one of the most rural, as only 18 percent of its live in urban centres. The country is one of the worlds least explored, culturally and geographically and it is known to have numerous groups of uncontacted peoples, and researchers believe there are many undiscovered species of plants and animals in the interior. Papua New Guinea is classified as an economy by the International Monetary Fund. Strong growth in Papua New Guineas mining and resource sector led to the becoming the sixth fastest-growing economy in the world in 2011. Growth was expected to slow once major resource projects came on line in 2015, mining remains a major economic factor, however. Local and national governments are discussing the potential of resuming mining operations in Panguna mine in Bougainville Province, nearly 40 percent of the population lives a self-sustainable natural lifestyle with no access to global capital. Most of the still live in strong traditional social groups based on farming. Their social lives combine traditional religion with modern practices, including primary education, at the national level, after being ruled by three external powers since 1884, Papua New Guinea established its sovereignty in 1975. This followed nearly 60 years of Australian administration, which started during the Great War and it became an independent Commonwealth realm with Queen Elizabeth II as its head of state and became a member of the Commonwealth of Nations in its own right. Archaeological evidence indicates that humans first arrived in Papua New Guinea around 42,000 to 45,000 years ago and they were descendants of migrants out of Africa, in one of the early waves of human migration. Agriculture was independently developed in the New Guinea highlands around 7000 BC, a major migration of Austronesian-speaking peoples to coastal regions of New Guinea took place around 500 BC. This has been correlated with the introduction of pottery, pigs, in the 18th century, traders brought the sweet potato to New Guinea, where it was adopted and became part of the staples. Portuguese traders had obtained it from South America and introduced it to the Moluccas, the far higher crop yields from sweet potato gardens radically transformed traditional agriculture and societies. Sweet potato largely supplanted the previous staple, taro, and resulted in a significant increase in population in the highlands. In 1901, on Goaribari Island in the Gulf of Papua, missionary Harry Dauncey found 10,000 skulls in the islands Long Houses, traders from Southeast Asia had visited New Guinea beginning 5,000 years ago to collect bird of paradise plumes
17.
Mammoth Cave National Park
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Mammoth Cave National Park is a U. S. national park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. Since the 1972 unification of Mammoth Cave with the system under Flint Ridge to the north. The park was established as a park on July 1,1941. It became a World Heritage Site on October 27,1981, the parks 52,830 acres are located primarily in Edmonson County, Kentucky, with small areas extending eastward into Hart County and Barren County. It is centered on the Green River, with a tributary, with 405 miles of surveyed passageways Mammoth Cave is by far the worlds longest known cave system, being over twice as long as the second-longest cave system, Mexicos Sac Actun underwater cave. Mammoth Cave developed in thick Mississippian-aged limestone strata capped by a layer of sandstone and it is known to include more than 390 miles of passageway, new discoveries and connections add several miles to this figure each year. Mammoth Cave National Park was established to preserve the cave system, the epikarstic zone concentrates local flows of runoff into high-elevation springs which emerge at the edges of ridges. It is in underlying massive limestone layers that the human-explorable caves of the region have naturally developed. The limestone layers of the column beneath the Big Clifty, in increasing order of depth below the ridgetops, are the Girkin Formation. Genevieve Limestone, and the St. Louis Limestone, for example, the large Main Cave passage seen on the Historic Tour is located at the bottom of the Girkin and the top of the Ste. Each of the layers of limestone is divided further into named geological units and subunits. One area of research involves correlating the stratigraphy with the cave survey produced by explorers. This makes it possible to produce approximate three-dimensional maps of the contours of the layer boundaries without the necessity for test wells. The upper sandstone caprock is relatively hard for water to penetrate, however, the sandstone caprock layer has been dissolved and eroded at many locations within the park, such as the Frozen Niagara room. At one valley bottom in the region of the park. Known as Cedar Sink, the features a small river entering one side. Mammoth Cave is home to the endangered Kentucky cave shrimp, a sightless albino shrimp, the National Park Service offers several cave tours to visitors. Some notable features of the cave, such as Grand Avenue, Frozen Niagara, two tours, lit only by visitor-carried paraffin lamps, are popular alternatives to the electric-lit routes
18.
Kentucky
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Kentucky, officially the Commonwealth of Kentucky, is a state located in the east south-central region of the United States. Kentucky is one of four U. S. states constituted as a commonwealth, originally a part of Virginia, in 1792 Kentucky became the 15th state to join the Union. Kentucky is the 37th most extensive and the 26th most populous of the 50 United States, Kentucky is known as the Bluegrass State, a nickname based on the bluegrass found in many of its pastures due to the fertile soil. One of the regions in Kentucky is the Bluegrass Region in central Kentucky. In 1776, the counties of Virginia beyond the Appalachian Mountains became known as Kentucky County, the precise etymology of the name is uncertain, but likely based on an Iroquoian name meaning the meadow or the prairie. Kentucky is situated in the Upland South, a significant portion of eastern Kentucky is part of Appalachia. Kentucky borders seven states, from the Midwest and the Southeast, West Virginia lies to the east, Virginia to the southeast, Tennessee to the south, Missouri to the west, Illinois and Indiana to the northwest, and Ohio to the north and northeast. Only Missouri and Tennessee, both of which border eight states, touch more, Kentuckys northern border is formed by the Ohio River and its western border by the Mississippi River. The official state borders are based on the courses of the rivers as they existed when Kentucky became a state in 1792, for instance, northbound travelers on U. S.41 from Henderson, after crossing the Ohio River, will be in Kentucky for about two miles. Ellis Park, a racetrack, is located in this small piece of Kentucky. Waterworks Road is part of the land border between Indiana and Kentucky. Kentucky has a part known as Kentucky Bend, at the far west corner of the state. It exists as an exclave surrounded completely by Missouri and Tennessee, Road access to this small part of Kentucky on the Mississippi River requires a trip through Tennessee. The epicenter of the powerful 1811–12 New Madrid earthquakes was near this area, much of the outer Bluegrass is in the Eden Shale Hills area, made up of short, steep, and very narrow hills. The Jackson Purchase and western Pennyrile are home to several bald cypress/tupelo swamps, located within the southeastern interior portion of North America, Kentucky has a climate that can best be described as a humid subtropical climate. Temperatures in Kentucky usually range from daytime summer highs of 87 °F to the low of 23 °F. The average precipitation is 46 inches a year, Kentucky experiences four distinct seasons, with substantial variations in the severity of summer and winter. The highest recorded temperature was 114 °F at Greensburg on July 28,1930 while the lowest recorded temperature was −37 °F at Shelbyville on January 19,1994, due to its location, Kentucky has a moderate humid subtropical climate, with abundant rainfall
19.
Underground stream
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A subterranean river is a river that runs wholly or partly beneath the ground surface – one where the riverbed does not represent the surface of the Earth. It should also not be confused with an aquifer which may flow like a river but is contained within a layer of rock or other unconsolidated materials. Subterranean rivers may be natural, flowing through cave systems. In karst topography, rivers may disappear through sinkholes, continuing underground, in some cases, they may emerge into daylight further downstream. Some fish and other organisms are adapted to life in subterranean rivers. Subterranean rivers can also be the result of covering over a river and/or diverting its flow into culverts, reversing this process is known as daylighting a stream and is a visible form of river restoration. One successful example is the Cheonggye Stream in the centre of Seoul, examples of subterranean rivers also occur in mythology and literature. There are many examples of subterranean rivers. Among others, The Camuy River located in the region of Puerto Rico is one of the largest underground river systems in the world. Greek mythology included the Styx, Phlegethon, Acheron, Cocytus, dante Alighieri, in his Inferno, included the Acheron, Phlegethon, and Styx as rivers within his subterranean Hell. The river Alph, running Through caverns measureless to man / Down to a sea is central to the poem Kubla Khan. The characters in Jules Vernes A Journey to the Centre of the Earth encounter a river, Hans was not mistaken. What you hear is the rushing of a torrent, there can be no doubt, a subterranean river is flowing around us. Several other novels also feature subterranean rivers, but in the end where a river has been, a river will always be. Hamza River Abîme Karst Losing stream Speleology Subterranean rivers of London Subterranean rivers in Hong Kong Subterranean waterfall Toronto ravine system Hamilton ravine system Underground lake
20.
Carbonate rock
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Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite and dolostone, which is composed of the mineral dolomite. Calcite can be dissolved by groundwater or precipitated by groundwater, depending on several factors including the water temperature, pH. Calcite exhibits a 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 caves develop in carbonate rocks because of their solubility in dilute acidic groundwater. Cooling groundwater or mixing of different groundwaters will also create conditions suitable for cave formation, marble is the metamorphic carbonate rock. Rare igneous carbonate rocks exist as intrusive carbonatites and even rarer volcanic carbonate lava
21.
Halite
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Halite, commonly known as rock salt, is a type of salt, the mineral form of sodium chloride. The mineral is colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount. It commonly occurs with other evaporite minerals such as several of the sulfates, halides. Halite occurs in vast beds of sedimentary evaporite minerals that result from the drying up of enclosed lakes, playas, salt beds may be hundreds of meters thick and underlie broad areas. In the United States and Canada extensive underground beds extend from the Appalachian basin of western New York through parts of Ontario, other deposits are in Ohio, Kansas, New Mexico, Nova Scotia and Saskatchewan. The Khewra salt mine is a deposit of halite near Islamabad. In the United Kingdom there are three mines, the largest of these is at Winsford in Cheshire producing on average a million tonnes per year. Salt domes are vertical diapirs or pipe-like masses of salt that have been squeezed up from underlying salt beds by mobilization due to the weight of overlying rock. Salt domes contain anhydrite, gypsum, and native sulfur, in addition to halite and sylvite and they are common along the Gulf coasts of Texas and Louisiana and are often associated with petroleum deposits. Germany, Spain, the Netherlands, Romania and Iran also have salt domes, salt glaciers exist in arid Iran where the salt has broken through the surface at high elevation and flows downhill. In all of these cases, halite is said to be behaving in the manner of a rheid, unusual, purple, fibrous vein filling halite is found in France and a few other localities. Halite crystals termed hopper crystals appear to be skeletons of the cubes, with the edges present and stairstep depressions on, or rather in. In a rapidly crystallizing environment, the edges of the cubes simply grow faster than the centers, halite crystals form very quickly in some rapidly evaporating lakes resulting in modern artifacts with a coating or encrustation of halite crystals. Halite flowers are rare stalactites of curling fibers of halite that are found in certain arid caves of Australias Nullarbor Plain, halite stalactites and encrustations are also reported in the Quincy native copper mine of Hancock, Michigan. Halite is often used both residentially and municipally for managing ice, because brine has a lower freezing point than pure water, putting salt or saltwater on ice that is near 0 °C will cause it to melt. It is common for homeowners in cold climates to spread salt on their sidewalks and driveways after a snow storm to melt the ice. It is not necessary to use so much salt that the ice is melted, rather. Also, many cities will spread a mixture of sand and salt on roads during, in addition to de-icing, rock salt is occasionally used in agriculture
22.
Groundwater
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Groundwater is the water present beneath Earths surface in soil pore spaces and in the fractures of rock formations. A unit of rock or a deposit is called an aquifer when it can yield a usable quantity of water. The depth at which pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the naturally, natural discharge often occurs at springs and seeps. Groundwater is also withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, Groundwater is hypothesized to provide lubrication that can possibly influence the movement of faults. It is likely that much of Earths subsurface contains some water, Groundwater may not be confined only to Earth. The formation of some of the landforms observed on Mars may have influenced by groundwater. There is also evidence that water may also exist in the subsurface of Jupiters moon Europa. Groundwater is often cheaper, more convenient and less vulnerable to pollution than surface water, therefore, it is commonly used for public water supplies. For example, groundwater provides the largest source of water storage in the United States. Underground reservoirs contain far more water than the capacity of all surface reservoirs and lakes in the US, many municipal water supplies are derived solely from groundwater. Polluted groundwater is less visible, but more difficult to clean up, than pollution in rivers, Groundwater pollution most often results from improper disposal of wastes on land. An aquifer is a layer of substrate that contains and transmits groundwater. When water can flow directly between the surface and the zone of an aquifer, the aquifer is unconfined. The deeper parts of unconfined aquifers are more saturated since gravity causes water to flow downward. The upper level of this layer of an unconfined aquifer is called the water table or phreatic surface. Below the water table, where in general all pore spaces are saturated with water, is the phreatic zone, substrate with low porosity that permits limited transmission of groundwater is known as an aquitard
23.
Quartzite
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Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. Sandstone is converted into quartzite through heating and pressure related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey, though quartzites often occur in shades of pink. Other colors, such as yellow, green, blue and orange, are due to other minerals, when sandstone is cemented to quartzite, the individual quartz grains recrystallize along with the former cementing material to form an interlocking mosaic of quartz crystals. Most or all of the texture and sedimentary structures of the sandstone are erased by the metamorphism. The grainy, sandpaper-like surface becomes glassy in appearance, minor amounts of former cementing materials, iron oxide, silica, carbonate and clay, often migrate during recrystallization and metamorphosis. This causes streaks and lenses to form within the quartzite, orthoquartzite is a very pure quartz sandstone composed of usually well-rounded quartz grains cemented by silica. Orthoquartzite is often 99% SiO2 with only minor amounts of iron oxide and trace resistant minerals such as zircon, rutile. Although few fossils are present, the original texture and sedimentary structures are preserved. The term is traditionally used for quartz-cemented quartz arenites. Quartzite is very resistant to weathering and often forms ridges. The nearly pure silica content of the rock provides little for soil, therefore, because of its hardness and angular shape, crushed quartzite is often used as railway ballast. Quartzite is a stone and may be used to cover walls, as roofing tiles, as flooring. Its use for countertops in kitchens is expanding rapidly and it is harder and more resistant to stains than granite. Crushed quartzite is used in road construction. High purity quartzite is used to produce ferrosilicon, industrial silica sand, during the Paleolithic quartzite was used, in addition to flint, quartz, and other lithic raw materials, for making stone tools. Quartzite is also found in the Morenci Copper Mine in Arizona, the town of Quartzsite in western Arizona derives its name from the quartzites in the nearby mountains in both Arizona and Southeastern California. A glassy vitreous quartzite has been described from the Belt Supergroup in the Coeur d’Alene district of northern Idaho, in the United Kingdom, a craggy ridge of quartzite called the Stiperstones runs parallel with the Pontesford-Linley fault,6 km north-west of the Long Mynd in south Shropshire
24.
Comet
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A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to evolve gasses, a process called outgassing. This produces an atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of collections of ice, dust. The coma may be up to 15 times the Earths diameter, if sufficiently bright, a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30° across the sky. Comets have been observed and recorded since ancient times by many cultures, Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun from the Oort cloud by gravitational perturbations caused by passing stars, hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space. The appearance of a comet is called an apparition, Comets are distinguished from asteroids by the presence of an extended, gravitationally unbound atmosphere surrounding their central nucleus. This atmosphere has parts termed the coma and the tail, however, extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a different origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System, the discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets. As of November 2014 there are 5,253 known comets, however, this represents only a tiny fraction of the total potential comet population, as the reservoir of comet-like bodies in the outer Solar System is estimated to be one trillion. Roughly one comet per year is visible to the eye, though many of those are faint. Particularly bright examples are called Great Comets, the word comet derives from the Old English cometa from the Latin comēta or comētēs. That, in turn, is a latinisation of the Greek κομήτης, Κομήτης was derived from κομᾶν, which was itself derived from κόμη and was used to mean the tail of a comet. The astronomical symbol for comets is ☄, consisting of a disc with three hairlike extensions. The solid, core structure of a comet is known as the nucleus, cometary nuclei are composed of an amalgamation of rock, dust, water ice, and frozen gases such as carbon dioxide, carbon monoxide, methane, and ammonia. As such, they are described as dirty snowballs after Fred Whipples model
25.
Rosetta (spacecraft)
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Rosetta was a space probe built by the European Space Agency launched on 2 March 2004. Along with Philae, its lander module, Rosetta performed a study of comet 67P/Churyumov–Gerasimenko. During its journey to the comet, the spacecraft flew by Mars and it was launched as the third cornerstone mission of the ESAs Horizon 2000 programme, after SOHO / Cluster and XMM-Newton. On 6 August 2014, the reached the comet and performed a series of manoeuvres to eventually orbit the comet at distances of 30 to 10 kilometres. On 12 November, its lander module Philae performed the first successful landing on a comet, communications with Philae were briefly restored in June and July 2015, but due to diminishing solar power, Rosettas communications module with the lander was turned off on 27 July 2016. On 30 September 2016, the Rosetta spacecraft ended its mission by hard-landing on the comet in its Maat region, the probe is named after the Rosetta Stone, a stele of Egyptian origin featuring a decree in three scripts. The lander is named after the Philae obelisk, which bears a bilingual Greek and it was one of ESAs Horizon 2000 cornerstone missions. The spacecraft consisted of the Rosetta orbiter, which featured 12 instruments, the Rosetta mission orbited Comet Churyumov–Gerasimenko for 17 months and was designed to complete the most detailed study of a comet ever attempted. The spacecraft was controlled from the European Space Operations Centre, in Darmstadt and it has been estimated that in the decade preceding 2014, some 2,000 people assisted in the mission in some capacity. In 2007, Rosetta made a Mars gravity assist on its way to Comet Churyumov–Gerasimenko, the spacecraft also performed two asteroid flybys. The craft completed its flyby of asteroid 2867 Šteins in September 2008, later, on 20 January 2014, Rosetta was taken out of a 31-month hibernation mode as it approached Comet Churyumov–Gerasimenko. Rosettas Philae lander successfully made the first soft landing on a comet nucleus when it touched down on Comet Churyumov–Gerasimenko on 12 November 2014. On 5 September 2016, ESA announced that the lander was discovered by the narrow-angle camera aboard Rosetta as the made a low,2.7 km pass over the comet. The lander sits on its side wedged into a crevice of the comet. During the 1986 approach of Halleys Comet, international space probes were sent to explore the comet, after the probes returned valuable scientific information, it became obvious that follow-ons were needed that would shed more light on cometary composition and answer new questions. Both ESA and NASA started cooperatively developing new probes, the NASA project was the Comet Rendezvous Asteroid Flyby mission. The ESA project was the follow-on Comet Nucleus Sample Return mission, both missions were to share the Mariner Mark II spacecraft design, thus minimising costs. In 1992, after NASA cancelled CRAF due to budgetary limitations, after the spacecraft launch, Gerhard Schwehm was named mission manager, he retired in March 2014
26.
Space probe
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A space probe is a robotic spacecraft that does not orbit the Earth, but, instead, explores further into outer space. A space probe may approach the Moon, travel through space, flyby, orbit, or land on other planetary bodies. Approximately fifteen missions are currently operational, once a probe has left the vicinity of Earth, its trajectory will likely take it along an orbit around the Sun similar to the Earths orbit. To reach another planet, the simplest practical method is a Hohmann transfer orbit, more complex techniques, such as gravitational slingshots, can be more fuel-efficient, though they may require the probe to spend more time in transit. Some high Delta-V missions can only be performed, within the limits of modern propulsion, a technique using very little propulsion, but requiring a considerable amount of time, is to follow a trajectory on the Interplanetary Transport Network. First man-made object to land on the Moon, or any other extra terrestrial surface. First mission to photograph the far side of the Moon, launched in 1959, first robotic sample return probe from the Moon. It was sent to the Moon on November 10,1970, first successful in-place analysis of another planet. It may have also been the first space probe to impact the surface of another planet, the Venera 7 probe was the first spacecraft to successfully soft land on another planet and to transmit data from there back to Earth. Upon its arrival at Mars on November 13,1971, Mariner 9 became the first space probe to orbit around another planet. Although, the spacecraft failed shortly after landing, the Mars Exploration Rovers, Spirit and Opportunity surface and geology, and searched for clues to past water activity on Mars. They were each launched in 2003 and landed in 2004, communication with Spirit stopped on sol 2210. JPL continued to attempt to regain contact until May 24,2011, Opportunity arrived at Endeavour crater on 9 August 2011, at a landmark called Spirit Point named after its rover twin, after traversing 13 miles from Victoria crater, over a three-year period. As of January 26,2016, Opportunity has lasted for more than twelve years on Mars — although the rovers were intended to last only three months. The first dedicated missions to a comet, in this case and they dropped landers and balloons at Venus before their rendezvous with Halleys Comet. This Japanese probe was the first non-US, non-Soviet interplanetary probe, a second Japanese probe, it made ultraviolet wavelength observations of the comet. The first space probe to penetrate a comets coma and take images of its nucleus. First solar wind sample return probe from sun-earth L1, first sample return probe from a comet tail
27.
Pinge
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A Pinge or Binge is the name given in German-speaking Europe to a wedge-, ditch- or funnel-shaped depression in the terrain caused by mining activity. This depression or sink-hole is frequently caused by the collapse of old mine workings that are close to the Earths surface. Unlike natural landforms, a Pinge is a result of human activity. The term has no equivalent in English, but may be translated as mining sink-hole, mine slump or, in some cases. In the original sense of the word, the mining terms Pinge or Binge go back to the activity known as pingen which meant something like prospecting, an aufgepingter lode was one near the surface of the ground. The Pinge was therefore like a primitive, open pit mine, subsequently the term was transferred to the funnel-shaped depressions that formed at the surface above filled or collapsed mineshafts. The latter occurred either as a result of the consequences of active mining or the subsidence above abandoned mines. They were sometimes willingly and knowingly accepted, for example, when mining was carried out by a known as block caving. A Pingenzug is a row of several Pingen in succession, a Pinge can arise in different ways. In some cases it is caused by surface excavation, in other cases it follows the extraction of mineral deposits at a shallow depth and the associated collapse of the overburden that can result in subsidence at the surface. Pingen caused by surface mining generally date to the 16th and 17th centuries and are mostly only 0.5 -1 metre deep, deeper Pingen, caused by collapse of the overburden, date to the 18th and 19th centuries. The Pinge is usually surrounded by a mound as a result of the subsidence of the surface of the terrain. A number of Pingen form trenches up to 250 metres long and 15 metres wide, initially, the extraction of ore or coal took place near the surface at outcrops of the main deposits. Excavations of seam-like deposits were carried out by digging out bowl-shaped depressions, the so-called Pütts, once digging reached the water table, groundwater ran into the hole. If the quantity of water was so great that it entered the pit faster than it could be drained, to make matters worse, the ingress of water and the consequent softening of the soil reduced the stability of the side walls. For this reason, the pit was abandoned in such cases. Over the years, these hollows became Pingen, in the southern Ruhr, there are numerous such Pingen caused by surface mining. Subsequent erosion and collapse has produced funnel-shaped hollows, the Pingen, where Pingen have resulted from surface mining, small ring-shaped tips were often made by dumping the waste rock
28.
Mining
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Mining is extraction of valuable minerals or other geological materials from the earth usually from an orebody, lode, vein, seam, reef or placer deposits. These deposits form a mineralized package that is of economic interest to the miner, ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain any material that cannot be grown through agricultural processes, Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Mining of stones and metal has been a human activity since pre-historic times, Mining operations usually create a negative environmental impact, both during the mining activity and after the mine has closed. Hence, most of the nations have passed regulations to decrease the impact. Work safety has long been a concern as well, and modern practices have significantly improved safety in mines, levels of metals recycling are generally low. Unless future end-of-life recycling rates are stepped up, some rare metals may become unavailable for use in a variety of consumer products, due to the low recycling rates, some landfills now contain higher concentrations of metal than mines themselves. Since the beginning of civilization, people have used stone, ceramics and, later and these were used to make early tools and weapons, for example, high quality flint found in northern France, southern England and Poland was used to create flint tools. Flint mines have been found in areas where seams of the stone were followed underground by shafts. The mines at Grimes Graves and Krzemionki are especially famous, other hard rocks mined or collected for axes included the greenstone of the Langdale axe industry based in the English Lake District. The oldest-known mine on archaeological record is the Lion Cave in Swaziland, at this site Paleolithic humans mined hematite to make the red pigment ochre. Mines of an age in Hungary are believed to be sites where Neanderthals may have mined flint for weapons. Ancient Egyptians mined malachite at Maadi, at first, Egyptians used the bright green malachite stones for ornamentations and pottery. Later, between 2613 and 2494 BC, large building projects required expeditions abroad to the area of Wadi Maghareh in order to secure minerals and other resources not available in Egypt itself. Quarries for turquoise and copper were found at Wadi Hammamat, Tura, Aswan and various other Nubian sites on the Sinai Peninsula. Mining in Egypt occurred in the earliest dynasties, the gold mines of Nubia were among the largest and most extensive of any in Ancient Egypt. These mines are described by the Greek author Diodorus Siculus, who mentions fire-setting as one used to break down the hard rock holding the gold. One of the complexes is shown in one of the earliest known maps, the miners crushed the ore and ground it to a fine powder before washing the powder for the gold dust
29.
Louisiana
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Louisiana is a state located in the southern region of the United States. Louisiana is the 31st most extensive and the 25th most populous of the 50 United States and its capital is Baton Rouge and largest city is New Orleans. Louisiana is the state in the U. S. with political subdivisions termed parishes. The largest parish by population is East Baton Rouge Parish, Louisiana is bordered by Arkansas to the north, Mississippi to the east, Texas to the west, and the Gulf of Mexico to the south. Much of the lands were formed from sediment washed down the Mississippi River, leaving enormous deltas and vast areas of coastal marsh. These contain a rich southern biota, typical examples include birds such as ibis, there are also many species of tree frogs, and fish such as sturgeon and paddlefish. In more elevated areas, fire is a process in the landscape. These support a large number of plant species, including many species of orchids. Louisiana has more Native American tribes than any other state, including four that are federally recognized, ten that are state recognized. Before the American purchase of the territory in 1803, the current Louisiana State had been both a French colony and for a period, a Spanish one. In addition, colonists imported numerous African people as slaves in the 18th century, many came from peoples of the same region of West Africa, thus concentrating their culture. Louisiana was named after Louis XIV, King of France from 1643 to 1715, when René-Robert Cavelier, Sieur de La Salle claimed the territory drained by the Mississippi River for France, he named it La Louisiane. The suffix -ana is a Latin suffix that can refer to information relating to an individual, subject. Thus, roughly, Louis + ana carries the idea of related to Louis, the Gulf of Mexico did not exist 250 million years ago when there was but one supercontinent, Pangea. As Pangea split apart, the Atlantic Ocean and Gulf of Mexico opened, Louisiana slowly developed, over millions of years, from water into land, and from north to south. The oldest rocks are exposed in the north, in such as the Kisatchie National Forest. The oldest rocks date back to the early Tertiary Era, some 60 million years ago, the history of the formation of these rocks can be found in D. Spearings Roadside Geology of Louisiana. The sediments were carried north to south by the Mississippi River
30.
Texas
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Texas is the second largest state in the United States by both area and population. Other major cities include Austin, the second most populous state capital in the U. S. Texas is nicknamed the Lone Star State to signify its former status as an independent republic, and as a reminder of the states struggle for independence from Mexico. The Lone Star can be found on the Texan state flag, the origin of Texass name is from the word Tejas, which means friends in the Caddo language. Due to its size and geologic features such as the Balcones Fault, although Texas is popularly associated with the U. S. southwestern deserts, less than 10 percent of Texas land area is desert. Most of the centers are located in areas of former prairies, grasslands, forests. Traveling from east to west, one can observe terrain that ranges from coastal swamps and piney woods, to rolling plains and rugged hills, the term six flags over Texas refers to several nations that have ruled over the territory. Spain was the first European country to claim the area of Texas, Mexico controlled the territory until 1836 when Texas won its independence, becoming an independent Republic. In 1845, Texas joined the United States as the 28th state, the states annexation set off a chain of events that caused the Mexican–American War in 1846. A slave state before the American Civil War, Texas declared its secession from the U. S. in early 1861, after the Civil War and the restoration of its representation in the federal government, Texas entered a long period of economic stagnation. One Texan industry that thrived after the Civil War was cattle, due to its long history as a center of the industry, Texas is associated with the image of the cowboy. The states economic fortunes changed in the early 20th century, when oil discoveries initiated a boom in the state. With strong investments in universities, Texas developed a diversified economy, as of 2010 it shares the top of the list of the most Fortune 500 companies with California at 57. With a growing base of industry, the leads in many industries, including agriculture, petrochemicals, energy, computers and electronics, aerospace. Texas has led the nation in export revenue since 2002 and has the second-highest gross state product. The name Texas, based on the Caddo word tejas meaning friends or allies, was applied by the Spanish to the Caddo themselves, during Spanish colonial rule, the area was officially known as the Nuevo Reino de Filipinas, La Provincia de Texas. Texas is the second largest U. S. state, behind Alaska, though 10 percent larger than France and almost twice as large as Germany or Japan, it ranks only 27th worldwide amongst country subdivisions by size. If it were an independent country, Texas would be the 40th largest behind Chile, Texas is in the south central part of the United States of America. Three of its borders are defined by rivers, the Rio Grande forms a natural border with the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas to the south
31.
Water supply network
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A water supply system or water supply network is a system of engineered hydrologic and hydraulic components which provide water supply. A water supply system includes, A drainage basin. A raw water collection point where the water accumulates, such as a lake, raw water may be transferred using uncovered ground-level aqueducts, covered tunnels or underground water pipes to water purification facilities. Treated water is transferred using water pipes, Water storage facilities such as reservoirs, water tanks, or water towers. Smaller water systems may store the water in cisterns or pressure vessels, tall buildings may also need to store water locally in pressure vessels in order for the water to reach the upper floors. Additional water pressurizing components such as pumping stations may need to be situated at the outlet of underground or above ground reservoirs or cisterns, a pipe network for distribution of water to the consumers and other usage points. Connections to the sewers are found downstream of the water consumers. Raw water is collected from a water source or from a groundwater source within the watershed that provides the water resource. The raw water is transferred to the water purification facilities using uncovered aqueducts, Water treatment must occur before the product reaches the consumer and afterwards. Water purification usually occurs close to the delivery points to reduce pumping costs. Traditional surface water treatment plants generally consists of three steps, clarification, filtration and disinfection, clarification refers to the separation of particles from the water stream. Chemical addition destabilizes the particle charges and prepares them for either by settling or floating out of the water stream. Sand, anthracite or activated carbon filters refine the water stream, while other methods of disinfection exist, the preferred method is via chlorine addition. Chlorine effectively kills bacteria and most viruses and maintains a residual to protect the supply through the supply network. The product, delivered to the point of consumption, is called potable water if it meets the quality standards required for human consumption. The water is typically pressurised by pumps that pump water into storage tanks constructed at the highest local point in the network, one network may have several such service reservoirs. In small domestic systems, the water may be pressurised by a vessel or even by an underground cistern. This eliminates the need of a water-tower or any other heightened water reserve to supply the water pressure and these systems are usually owned and maintained by local governments, such as cities, or other public entities, but are occasionally operated by a commercial enterprise
32.
Sanitary sewer
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A sanitary sewer or foul sewer is an underground carriage system specifically for transporting sewage from houses and commercial buildings through pipes to treatment or disposal. Sanitary sewers are part of a system called sewerage or sewage system. Sewage may be treated to water pollution before discharge to surface waters. Sanitary sewers serving industrial areas also carry industrial wastewater, separate sanitary sewer systems are designed to transport sewage alone. In municipalities served by sewers, separate storm drains may be constructed to convey surface runoff directly to surface waters. Sanitary sewers are distinguished from combined sewers, which combine sewage with stormwater runoff in the same pipe, sanitary sewer systems are considered beneficial because they avoid combined sewer overflows. To overcome these disadvantages, some cities built separate sanitary sewers to collect only municipal wastewater, the decision between a combined sewer system or two separate systems is mainly based on need for sewage treatment and cost of providing treatment during heavy rain events. Many cities with combined sewer systems built prior to sewage treatment have not replaced those sewer systems, in the developed world, sewers are pipes from buildings to one or more levels of larger underground trunk mains, which transport the sewage to sewage treatment facilities. Vertical pipes, usually made of precast concrete, called manholes, depending upon site application and use, these vertical pipes can be cylindrical, eccentric or concentric. The manholes are used for access to the pipes for inspection and maintenance. They also facilitate vertical and horizontal angles in otherwise straight pipelines, pipes conveying sewage from an individual building to a common gravity sewer line are called laterals. Branch sewers typically run under streets receiving laterals from buildings along that street, larger cities may have sewers called interceptors receiving flow from multiple trunk sewers. Design and sizing of sanitary sewers considers the population to be served over the life of the sewer, per capita wastewater production. Commercial and industrial flows are considered, but diversion of surface runoff to storm drains eliminates wet weather flow peaks of inefficient combined sewers. Pumps may be necessary where gravity sewers serve areas at lower elevations than the treatment plant. A lift station is a gravity sewer sump with a pump to lift accumulated sewage to a higher elevation, the pump may discharge to another gravity sewer at that location or may discharge through a pressurized force main to some distant location. Most of the solids are removed by the tanks, so the treatment plant can be much smaller than a typical plant. In addition, because of the vast reduction in solid waste, because the wastestream is pressurized, they can be laid just below the ground surface along the lands contour
33.
Pipeline transport
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Pipeline transport is the transportation of goods or material through a pipe. The latest data, in 2014, gives a total of less than 2,175,000 miles of pipeline in 120 countries of the world. The United States had 65%, Russia had 8%, and Canada had 3%, Pipeline and Gas Journal’s worldwide survey figures indicate that 118,623 miles of pipelines are planned and under construction. Of these,88,976 miles represent projects in the planning, Liquids and gases are transported in pipelines and any chemically stable substance can be sent through a pipeline. Pipelines exist for the transport of crude and refined petroleum, fuels - such as oil, natural gas and biofuels - and other fluids including sewage, slurry, water, pneumatic tubes using compressed air can be used to transport solid capsules. Oil pipelines are made from steel or plastic tubes which are usually buried, the oil is moved through the pipelines by pump stations along the pipeline. Natural gas are lightly pressurised into liquids known as Natural Gas Liquids, Natural gas pipelines are constructed of carbon steel. Highly toxic ammonia is theoretically the most dangerous substance to be transported through long-distance pipelines, hydrogen pipeline transport is the transportation of hydrogen through a pipe. District heating or teleheating systems use a network of insulated pipes which transport heated water, pipelines conveying flammable or explosive material, such as natural gas or oil, pose special safety concerns and there have been various accidents. Pipelines can be the target of vandalism, sabotage, or even terrorist attacks, in war, pipelines are often the target of military attacks. It is uncertain when the first crude oil pipeline was built, pipelines are generally the most economical way to transport large quantities of oil, refined oil products or natural gas over land. Natural gas are lightly pressurized into liquids knows as Natural Gas Liquids, small NGL processing facilities can be located in oil fields so the butane and propane liquid under light pressure of 125 pounds per square inch, can be shipped by rail, truck or pipeline. Propane can be used as a fuel in oil fields to heat various facilities used by the oil drillers or equipment and trucks used in the oil patch. EG, Propane will convert from a gas to a liquid under pressure,100 psi, give or take depending on temperature. Pipelines and rail cars use about double that pressure to pump at 250 psi, the distance to ship propane to markets is much shorter, as thousands of natural-gas processing plants are located in or near oil fields. Compared to shipping by railroad, pipelines have lower cost per unit, pipelines are preferable to transportation by truck for a number of reasons. Employment on completed pipelines represents only 1% of that of the trucking industry and this allows the Bakken Basin and Three Forks oil producers to get higher negotiated prices for their oil because they will not be restricted to just one wholesale market in the US. The distance from the biggest oil patch in North Dakota, is Williston, North Dakota, only about 85 miles or 137 kilometers to the Canada–US border, mutual funds and joint ventures are big investors in new oil and gas pipelines
34.
Surface water
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Surface water is water on the surface of the planet such as in a river, lake, wetland, or ocean. It can be contrasted with groundwater and atmospheric water, non-saline surface water is replenished by precipitation and by recruitment from ground-water. Surface and groundwater are two entities, so they must be regarded as such. However, there is an ever-increasing need for management of the two as they are part of a system that is paramount when the demand for water exceeds the available supply. Depletion of surface and ground water sources for public consumption is caused by over-pumping, aquifers near river systems that are over-pumped have been known to deplete surface water sources as well. Research supporting this has found in numerous water budgets for a multitude of cities. Response times for an aquifer are long, however, a total ban on ground water usage during water recessions would allow surface water to retain better levels required for sustainable aquatic life. By reducing ground water pumping, the water supplies will be able to maintain their levels, as they recharge from direct precipitation, surface runoff. Environmental persistent pharmaceutical pollutant Meltwater Optimum water content for tillage Applied Hydrogeology, Fourth Edition by C. W. Fetter
35.
Alapaha River
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The Alapaha River /əˈlæpəhɑː/ is a 202-mile-long river in southern Georgia and northern Florida in the United States. It is a tributary of the Suwannee River, which flows to the Gulf of Mexico, the Hernando de Soto expedition narrative records mention a Yupaha village they encountered after they left Apalachee, the sound of which is suggestive of the Alapaha, a tributary of the Suwanee. Another reference to a village of Atapaha so closely resembles Alapaha that it is reasonable to suppose they are the same, augustine, Florida, probably on the Alapaha River. In the 1840s a German travel writer, Friedrich Gerstäcker wrote a novel called Alapaha, or the Renegades of the Border. A translation of this novel was published in the 1870s as #67 in a series of American narratives published by Beadle. During the American Civil War, the swamps along the Alapaha River in Berrien, Irwin, along its course it passes the Georgia towns of Rebecca, Alapaha, Willacoochee, Lakeland, and Statenville. Near Willacoochee, Georgia, the Alapaha collects the Willacoochee River, in Florida, it collects the Alapahoochee River and the short Little Alapaha River, which rises in Echols County, Georgia, and flows southwestward. The Alapaha River is an intermittent river for part of its course, during periods of low volume, the river disappears underground and becomes a subterranean river. At approximately 2.3 miles downstream from Jennings, Florida is a river sinkhole variously known as the Alapaha River Sink, Suck Hole and it is located at 30. 5855009°N83. 0528016°W /30.5855009, -83.0528016. A short distance away from the Devils Dens, the Dead River enters into the Alapaha River and it is a usually dry river bed with a number of sinkholes, including the Dead River Sink. A few more miles downstream is a sinkhole known as the Dead River Sink or the Siphon. At the latter point during the periods of low water flow, the Alapaha River later reappears at the Alapaha River Rise, which is about a half mile upstream from the confluence of the Alapaha River and the Suwanee River. During a period of low rainfall over 11 miles of the riverbed can be dry as the river goes underground, the United States Board on Geographic Names settled on Alapaha River as the streams name in 1891. According to the Geographic Names Information System, it has also known as
36.
Jennings, Florida
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Jennings is a town in Hamilton County, Florida, United States. The population was 833 at the 2000 census, as of 2004, the population recorded by the U. S. Census Bureau was 843. Jennings is located at 30°36′11″N 83°6′8″W, according to the United States Census Bureau, the town has a total area of 1.8 square miles, all land. As of the census of 2000, there were 833 people,282 households, the population density was 461.3 people per square mile. There were 321 housing units at a density of 177.8 per square mile. The racial makeup of the town was 43. 70% White,43. 10% African American,0. 60% Native American,0. 60% Asian,10. 08% from other races, hispanic or Latino of any race were 22. 69% of the population. 23. 0% of all households were made up of individuals and 11. 7% had someone living alone who was 65 years of age or older, the average household size was 2.89 and the average family size was 3.34. In the town, the population was out with 30. 6% under the age of 18,9. 0% from 18 to 24,25. 7% from 25 to 44,22. 4% from 45 to 64. The median age was 32 years, for every 100 females there were 98.8 males. For every 100 females age 18 and over, there were 99.3 males, the median income for a household in the town was $25,714, and the median income for a family was $25,938. Males had an income of $25,577 versus $15,982 for females. The per capita income for the town was $12,195, about 23. 8% of families and 30. 8% of the population were below the poverty line, including 42. 9% of those under age 18 and 20. 0% of those age 65 or over. North Hamilton Elementary will be consolidated into a new school, Hamilton County Elementary School. Its opening is scheduled for August 2017, the Suwannee River Regional Library System operates the Jennings Public Library
37.
Floridan aquifer
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It underlies the entire state of Florida and parts of Alabama, Georgia, Mississippi, and South Carolina. The Floridan aquifer system is one of the worlds most productive aquifers, according to the U. S. Geological Survey, total withdrawals from the Floridan aquifer system in 2000 were ranked 5th highest of all principle aquifers in the Nation at 3,640 million gallons per day. Of the total, 49% was used for irrigation, 33% was used for water supply, 14% was used for industrial purposes. In 1936, geologist Victor Timothy Stringfield first identified the existence of the Floridan Aquifer in peninsular Florida and referred to the carbonate units as the principal artesian formations. In 1944, M. A. Warren of the Georgia Geological Survey described an extension of system in south Georgia. In 1953 and 1966 Stringfield also applied the term principal artesian aquifer to these rocks, with additional information collection, more zones of high and low hydraulic conductivity have been identified. As a result, the name Floridan Aquifer has evolved into Floridan aquifer system, withdrawals from the Floridan aquifer system began in 1887 when the City of Savannah, Georgia, began to supplement surface water withdrawals from the Savannah River with groundwater. Over time, the number of wells increased, as did the finished depths, industrial supply for pulp and paper mills became a large proportion of the water withdrawn starting in the late 1930s. In the 1950s, all municipal, domestic, and industrial supply and about half of agricultural supply in Orlando, groundwater withdrawals from the Floridan aquifer system increased steadily from 630 Mgal/d in 1950 to 3,430 Mgal/d in 1990. Much of the increase was due to increased agricultural demand, the Upper Floridan aquifer contains freshwater over much of its extent, though is brackish and saline south of Lake Okeechobee. The Floridan aquifer system crops out in central and southern Georgia where the limestone, the aquifer system generally dips below land surface to the south where it becomes buried beneath surficial sand deposits and clay. In areas depicted in brown in the image at the right and these regions particularly prone to sinkhole activity due to the proximity of the karstified limestone aquifer to land surface. Some of the fractures/conduits within the aquifer are large enough for divers to swim through. In west-central Florida, north Florida, and along the margin of the system, the limestone crops out. Where low-permeability clays of the upper confining unit are present and substantial, low permeability limestone rocks of Paleocene age form the base of the Floridan aquifer system. The Floridan aquifer system ranges in thickness from less than 100 feet in areas where the rocks pinch out to more than 3,700 feet in southwestern Florida. Where the Floridan aquifer system is at or near surface, clays are thin or absent and dissolution of the limestone is intensified and many springs. Transmissivity of the aquifer in karstified areas such as these is much higher owing to the development of large, Springs form where the water pressure is great enough for the groundwater to flow out on the land surface
38.
Subterranean river
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A subterranean river is a river that runs wholly or partly beneath the ground surface – one where the riverbed does not represent the surface of the Earth. It should also not be confused with an aquifer which may flow like a river but is contained within a layer of rock or other unconsolidated materials. Subterranean rivers may be natural, flowing through cave systems. In karst topography, rivers may disappear through sinkholes, continuing underground, in some cases, they may emerge into daylight further downstream. Some fish and other organisms are adapted to life in subterranean rivers. Subterranean rivers can also be the result of covering over a river and/or diverting its flow into culverts, reversing this process is known as daylighting a stream and is a visible form of river restoration. One successful example is the Cheonggye Stream in the centre of Seoul, examples of subterranean rivers also occur in mythology and literature. There are many examples of subterranean rivers. Among others, The Camuy River located in the region of Puerto Rico is one of the largest underground river systems in the world. Greek mythology included the Styx, Phlegethon, Acheron, Cocytus, dante Alighieri, in his Inferno, included the Acheron, Phlegethon, and Styx as rivers within his subterranean Hell. The river Alph, running Through caverns measureless to man / Down to a sea is central to the poem Kubla Khan. The characters in Jules Vernes A Journey to the Centre of the Earth encounter a river, Hans was not mistaken. What you hear is the rushing of a torrent, there can be no doubt, a subterranean river is flowing around us. Several other novels also feature subterranean rivers, but in the end where a river has been, a river will always be. Hamza River Abîme Karst Losing stream Speleology Subterranean rivers of London Subterranean rivers in Hong Kong Subterranean waterfall Toronto ravine system Hamilton ravine system Underground lake
39.
Laos
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Present day Laos traces its historic and cultural identity to the kingdom of Lan Xang Hom Khao, which existed for four centuries as one of the largest kingdoms in Southeast Asia. Due to Lan Xangs central geographical location in Southeast Asia, the kingdom was able to become a hub for overland trade. After a period of conflict, Lan Xang broke off into three separate kingdoms— Luang Phabang, Vientiane and Champasak. In 1893, it became a French protectorate, with the three territories uniting to form what is now known as the country of Laos and it briefly gained independence in 1945 after Japanese occupation, but returned to French rule until it was granted autonomy in 1949. Laos became independent in 1953, with a monarchy under Sisavang Vong. Shortly after independence, a civil war ended the monarchy. Laos is a one-party socialist republic and it espouses Marxism and is governed by the Lao Peoples Revolutionary Party, in which the party leadership is dominated by military figures. The Socialist Republic of Vietnam and the Vietnam Peoples Army continue to have significant influence in Laos, other large cities include Luang Prabang, Savannakhet, and Pakse. Laos is a country with the politically and culturally dominant Lao people making up approximately 60 percent of the population. Mon-Khmer groups, the Hmong, and other hill tribes, accounting for 40 percent of the population, live in the foothills. It is a member of the Asia-Pacific Trade Agreement, Association of Southeast Asian Nations, East Asia Summit, Laos applied for membership of the World Trade Organization in 1997, on 2 February 2013, it was granted full membership. According to the anti-corruption non-governmental organisation Transparency International, Laos remains one of the most corrupt countries in the world and this has deterred foreign investment and created major problems with the rule of law, including the nations ability to enforce contract and business regulation. This has contributed to a third of the population of Laos currently living below the poverty line. Laos has an economy, with one of the lowest annual incomes in the world. In 2014, the country ranked 141st on the Human Development Index, according to the Global Hunger Index, Laos ranks as the 29th hungriest nation in the world out of the list of the 52 nations with the worst hunger situation. Laos has also had a human rights record. In the Lao language, the name is Muang Lao or Pathet Lao. Stone artefacts including Hoabinhian types have been found at sites dating to the Late Pleistocene in northern Laos, archaeological evidence suggests agriculturist society developed during the 4th millennium BC
40.
Sima Humboldt
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Sima Humboldt is an enormous sinkhole located on the summit of the plateau of Sarisariñama tepui in Bolívar State, Venezuela. The feature is named after scientist and explorer Alexander von Humboldt, together with the neighbouring Sima Martel, it was first spotted in 1961 by pilot Harry Gibson. The sinkhole was descended for the first time in 1974 and more thoroughly explored in 1976 and its volume is 18,000,000 m3, with a maximum width of 352 m at its upper rim and 502 m below, and a depth of 314 m. Only 700 metres from the rim of Sima Humboldt there is another enormous sinkhole, in total there are four caves on Sarisariñama
41.
Sima Martel
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Sima Martel is an enormous sinkhole located on the summit of plateau of Sarisariñama tepui, in Bolívar State, Venezuela. It is unusual due to factors including its enormous size and depth, location on the top of the only forested tepui. Together with the neighbouring Sima Humboldt it was first spotted in 1961 by pilot Harry Gibson and it was first explored in 1971, and later was explored more thoroughly in 1976. In total there are four caves on Sarisariñama
42.
Venezuela
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Venezuela, officially the Bolivarian Republic of Venezuela, is a federal republic located on the northern coast of South America. It is bordered by Colombia on the west, Brazil on the south, Guyana on the east, Venezuela covers 916,445 km2 and has an estimated population of 31775371. The territory now known as Venezuela was colonized by Spain in 1522 amid resistance from indigenous peoples and it gained full independence as a separate country in 1830. During the 19th century, Venezuela suffered political turmoil and autocracy, since 1958, the country has had a series of democratic governments. This new constitution changed the name of the country to República Bolivariana de Venezuela. Venezuela is a presidential republic consisting of 23 states, the Capital District. Venezuela also claims all Guyanese territory west of the Essequibo River, oil was discovered in the early 20th century, and Venezuela has the worlds largest known oil reserves and has been one of the worlds leading exporters of oil. Previously an underdeveloped exporter of commodities such as coffee and cocoa, oil quickly came to dominate exports. The recovery of oil prices in the early 2000s gave Venezuela oil funds not seen since the 1980s, the Venezuelan government then established populist policies that initially boosted the Venezuelan economy and increased social spending, significantly reducing economic inequality and poverty. However, such policies later became controversial since they destabilized the economy, resulting in hyperinflation, an economic depression. According to the most popular and accepted version, in 1499, the stilt houses in the area of Lake Maracaibo reminded the navigator, Amerigo Vespucci, of the city of Venice, so he named the region Veneziola Piccola Venezia. The name acquired its current spelling as a result of Spanish influence, where the suffix -uela is used as a term, thus. The German language 16th century-term for the area, Klein-Venedig, also means little Venice, however, Martín Fernández de Enciso, a member of the Vespucci and Ojeda crew, gave a different account. In his work Summa de geografía, he states that they found people who called themselves the Veneciuela. Thus, the name Venezuela may have evolved from the native word and it is not known how many people lived in Venezuela before the Spanish conquest, it has been estimated at around one million. In addition to indigenous peoples known today, the population included historic groups such as the Kalina, Auaké, Caquetio, Mariche, the Timoto-Cuica culture was the most complex society in Pre-Columbian Venezuela, with pre-planned permanent villages, surrounded by irrigated, terraced fields. They also stored water in tanks and their houses were made primarily of stone and wood with thatched roofs. They were peaceful, for the most part, and depended on growing crops, regional crops included potatoes and ullucos
43.
New Britain
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New Britain is the largest island in the Bismarck Archipelago of Papua New Guinea. It is separated from the island of New Guinea by the Dampier and Vitiaz Straits, the main towns of New Britain are Rabaul/Kokopo and Kimbe. The island is roughly the size of Taiwan, while the island was part of German New Guinea, it was named Neupommern. New Britain extends from 148°1831 to 152°2357 E longitude and from 4°0825 to 6°1831 S latitude and it is crescent-shaped, approximately 520 km along its southeastern coastline, and from 29 to 146 km wide, not including a small central peninsula. The air-line distance from west to east is 477 km, the island is the 38th largest in the world, with an area of 36,520 km2. Steep cliffs form some sections of the coastline, in others the mountains are further inland, the highest point, at 2,438 m, is Mount Sinewit in the Baining range in the east. Most of the terrain is covered with tropical rainforest and several rivers are fed by the high rainfall. A major eruption of Tavurvur in 1994 destroyed the East New Britain provincial capital of Rabaul, most of the town still lies under metres of ash, and the capital has been moved to nearby Kokopo. New Britain forms part of the Islands Region, one of four regions of Papua New Guinea, New Britain became part of German New Guinea. In 1909, the population was estimated at about 190,000. The expatriate population was confined to the northeastern Gazelle Peninsula. At the time 5,448 hectares had been converted to plantations, primarily growing copra, cotton, coffee, westerners avoided exploring the interior initially, believing that the indigenous peoples were warlike and would fiercely resist intrusions. On 11 September 1914, New Britain became the site of one of the earliest battles of World War I when the Australian Naval and they quickly overwhelmed the German forces and occupied the island for the duration of the war. After World War I the Treaty of Versailles was signed in June 1919, in 1920 the League of Nations included New Britain along with the former German colony on New Guinea in the Territory of New Guinea, a mandated territory of Australia. During World War II the Japanese attacked New Britain soon after the outbreak of hostilities in the Pacific Ocean, strategic bases at Rabaul and Kavieng were defended by a small Australian detachment, Lark Force. During January 1942, the Japanese heavily bombed Rabaul, on 23 January, Japanese marines landed by the thousands, starting the Battle of Rabaul. The Japanese used Rabaul as a key base until 1944, it served as the key point for the invasion of Port Moresby. New Britain was invaded by the U. S, 1st Marine Division in the Cape Gloucester area of the very western end of the island, and also by U. S. Army soldiers at some other coastal points
44.
Xiaozhai Tiankeng
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The Xiaozhai Tiankeng, also known as the Heavenly Pit, is the worlds deepest sinkhole. It is located in Fengjie County of Chongqing Municipality, the Xiaozhai Tiankeng is 626 metres long,537 metres wide, and between 511 to 662 metres deep, with vertical walls. Its volume is 119,349,000 m³ and the area of its opening is 274,000 m² and this material has been dissolved and carried away by the river. The sinkhole is a doubly nested structure—the upper bowl is 320 metres deep, the bowl is 342 metres deep. Between both these steps is a ledge, formed due to soil trapped in the limestone. In the rainy season, a waterfall can be seen at the mouth of the sinkhole, the Xiaozhai Tiankeng was discovered by specialists in 1994 during a search for a new exploration site for British cavers in the China Caves Project. In fact, it was known to local people since ancient times. Xiaozhai is the name of a village nearby and literally means little village, and Tiankeng means Heavenly Pit. A2, 800-step stair has been constructed in order to facilitate tourism, the Tiankeng formed over the Difeng cave, which in turn had been formed by a powerful underground river which still flows underneath the sinkhole. The underground river starts in the Tianjing fissure gorge and reaches a vertical cliff above the Migong River, the length of this underground river is approximately 8.5 km and during these 8.5 kilometres, it falls 364 metres. The median annual flow of river is 8.77 m³ per second. Both the river and Difeng Cave were explored and mapped by China Caves Project in 1994,1,285 species of plants, including ginkgo, and many rare animals like the clouded leopard have been found in the sinkhole
