162-566: The Marble Arch Caves are a series of natural limestone caves located near the village of Florencecourt in County Fermanagh , Northern Ireland . The caves are named after the nearby Marble Arch, a natural limestone arch at the upstream end of Cladagh Glen under which the Cladagh River flows. The caves are formed from three rivers draining off the northern slopes of Cuilcagh mountain, which combine underground to form
324-455: A Mohs hardness of 2 to 4, dense limestone can have a crushing strength of up to 180 MPa . For comparison, concrete typically has a crushing strength of about 40 MPa. Although limestones show little variability in mineral composition, they show great diversity in texture. However, most limestone consists of sand-sized grains in a carbonate mud matrix. Because limestones are often of biological origin and are usually composed of sediment that
486-463: A bloom of cyanobacteria or microalgae . However, stable isotope ratios in modern carbonate mud appear to be inconsistent with either of these mechanisms, and abrasion of carbonate grains in high-energy environments has been put forward as a third possibility. Formation of limestone has likely been dominated by biological processes throughout the Phanerozoic , the last 540 million years of
648-584: A canvas boat, and with candles and magnesium flares for light, Martel and Jameson found 300 metres (1,000 ft) of passages, including the junction where the three rivers (the Owenbrean and the combined Aghinrawn and Sruh Croppa) meet. They drew a map of the discoveries and line drawings depicting the expedition, noting the upstream conclusion by boat in the Grand Gallery, and on foot at Pool Chamber. Today, this route to Pool Chamber forms part of
810-434: A carbonate rock outcrop can be estimated in the field by etching the surface with dilute hydrochloric acid. This etches away the calcite and aragonite, leaving behind any silica or dolomite grains. The latter can be identified by their rhombohedral shape. Crystals of calcite, quartz , dolomite or barite may line small cavities ( vugs ) in the rock. Vugs are a form of secondary porosity, formed in existing limestone by
972-616: A central quartz grain or carbonate mineral fragment. These likely form by direct precipitation of calcium carbonate onto the ooid. Pisoliths are similar to ooids, but they are larger than 2 mm in diameter and tend to be more irregular in shape. Limestone composed mostly of ooids is called an oolite or sometimes an oolitic limestone . Ooids form in high-energy environments, such as the Bahama platform, and oolites typically show crossbedding and other features associated with deposition in strong currents. Oncoliths resemble ooids but show
1134-518: A ceremonial county, or be a district tier within a shire county , be a royal or metropolitan borough , have borough or city status , or be a unitary authority . At the community level, much of England is divided into civil parishes with their own councils ; in Greater London only one such parish, Queen's Park , exists as of 2014 after they were abolished in 1965 until legislation allowed their recreation in 2007. From 1994 until
1296-449: A change in environment that increases the solubility of calcite. Dense, massive limestone is sometimes described as "marble". For example, the famous Portoro "marble" of Italy is actually a dense black limestone. True marble is produced by recrystallization of limestone during regional metamorphism that accompanies the mountain building process ( orogeny ). It is distinguished from dense limestone by its coarse crystalline texture and
1458-949: A composition reflecting the organisms that produced them and the environment in which they were produced. Low-magnesium calcite skeletal grains are typical of articulate brachiopods , planktonic (free-floating) foraminifera, and coccoliths . High-magnesium calcite skeletal grains are typical of benthic (bottom-dwelling) foraminifera, echinoderms , and coralline algae . Aragonite skeletal grains are typical of molluscs , calcareous green algae , stromatoporoids , corals , and tube worms . The skeletal grains also reflect specific geological periods and environments. For example, coral grains are more common in high-energy environments (characterized by strong currents and turbulence) while bryozoan grains are more common in low-energy environments (characterized by quiet water). Ooids (sometimes called ooliths) are sand-sized grains (less than 2mm in diameter) consisting of one or more layers of calcite or aragonite around
1620-412: A considerable fraction of the limestone bed. At depths greater than 1 km (0.62 miles), burial cementation completes the lithification process. Burial cementation does not produce stylolites. When overlying beds are eroded, bringing limestone closer to the surface, the final stage of diagenesis takes place. This produces secondary porosity as some of the cement is dissolved by rainwater infiltrating
1782-531: A direct hydrological connection from the Aghinrawn River sink at Monastir cliff, via Upper Cradle Hole Cave (situated on the south side of Cradle Hole), to the Cladagh Glen resurgence. While surveying Lower Cradle Hole Cave, one caver sent a floating candle downstream along the river, until it floated under a low ceiling out of sight at the end of the known passage. On plotting the surveyed passage on
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#17327759273001944-483: A drop of dilute hydrochloric acid is dropped on it. Dolomite is also soft but reacts only feebly with dilute hydrochloric acid, and it usually weathers to a characteristic dull yellow-brown color due to the presence of ferrous iron. This is released and oxidized as the dolomite weathers. Impurities (such as clay , sand, organic remains, iron oxide , and other materials) will cause limestones to exhibit different colors, especially with weathered surfaces. The makeup of
2106-637: A few million years, as this is the most stable form of calcium carbonate. Ancient carbonate formations of the Precambrian and Paleozoic contain abundant dolomite, but limestone dominates the carbonate beds of the Mesozoic and Cenozoic . Modern dolomite is quite rare. There is evidence that, while the modern ocean favors precipitation of aragonite, the oceans of the Paleozoic and middle to late Cenozoic favored precipitation of calcite. This may indicate
2268-455: A few thousand years. As rainwater mixes with groundwater, aragonite and high-magnesium calcite are converted to low-calcium calcite. Cementing of thick carbonate deposits by rainwater may commence even before the retreat of the sea, as rainwater can infiltrate over 100 km (60 miles) into sediments beneath the continental shelf. As carbonate sediments are increasingly deeply buried under younger sediments, chemical and mechanical compaction of
2430-512: A geographical frame of reference. Of these, 38 developed gradually since the Middle Ages ; these were reformed to 51 in 1974 and to their current number in 1996. Each has a Lord Lieutenant and High Sheriff ; these posts are used to represent the British monarch locally. Some counties, such as Herefordshire , are only divided further into civil parishes. The royal county of Berkshire and
2592-490: A high percentage of the mineral dolomite , CaMg(CO 3 ) 2 . Magnesian limestone is an obsolete and poorly-defined term used variously for dolomite, for limestone containing significant dolomite ( dolomitic limestone ), or for any other limestone containing a significant percentage of magnesium . Most limestone was formed in shallow marine environments, such as continental shelves or platforms , though smaller amounts were formed in many other environments. Much dolomite
2754-435: A limestone sample except in thin section and are less common in ancient limestones, possibly because compaction of carbonate sediments disrupts them. Limeclasts are fragments of existing limestone or partially lithified carbonate sediments. Intraclasts are limeclasts that originate close to where they are deposited in limestone, while extraclasts come from outside the depositional area. Intraclasts include grapestone , which
2916-471: A lower Mg/Ca ratio in the ocean water of those times. This magnesium depletion may be a consequence of more rapid sea floor spreading , which removes magnesium from ocean water. The modern ocean and the ocean of the Mesozoic have been described as "aragonite seas". Most limestone was formed in shallow marine environments, such as continental shelves or platforms . Such environments form only about 5% of
3078-525: A lower diversity of organisms and a greater fraction of silica and clay minerals characteristic of marls . The Green River Formation is an example of a prominent freshwater sedimentary formation containing numerous limestone beds. Freshwater limestone is typically micritic. Fossils of charophyte (stonewort), a form of freshwater green algae, are characteristic of these environments, where the charophytes produce and trap carbonates. Limestones may also form in evaporite depositional environments . Calcite
3240-495: A map alongside Marble Arch Cave, it was apparent that only 9 metres (30 ft) separated the end of this passage from the upstream end of the Grand Gallery, and it was postulated that a connection between the two might be forged. No further exploration was made until Easter 1935 when another group from the Yorkshire Ramblers' Club made their way from England . In wet conditions, the cavers re-entered Pool Chamber via
3402-523: A mechanism for dolomitization, with one 2004 review paper describing it bluntly as "a myth". Ordinary seawater is capable of converting calcite to dolomite, if the seawater is regularly flushed through the rock, as by the ebb and flow of tides (tidal pumping). Once dolomitization begins, it proceeds rapidly, so that there is very little carbonate rock containing mixed calcite and dolomite. Carbonate rock tends to be either almost all calcite/aragonite or almost all dolomite. About 20% to 25% of sedimentary rock
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#17327759273003564-448: A plausible source of mud. Another possibility is direct precipitation from the water. A phenomenon known as whitings occurs in shallow waters, in which white streaks containing dispersed micrite appear on the surface of the water. It is uncertain whether this is freshly precipitated aragonite or simply material stirred up from the bottom, but there is some evidence that whitings are caused by biological precipitation of aragonite as part of
3726-660: A profound and permanent effect on the English language. Subsequently, the House of Plantagenet from Anjou inherited the English throne under Henry II , adding England to the budding Angevin Empire of fiefs the family had inherited in France including Aquitaine . They reigned for three centuries, some noted monarchs being Richard I , Edward I , Edward III and Henry V . The period saw changes in trade and legislation, including
3888-449: A radial rather than layered internal structure, indicating that they were formed by algae in a normal marine environment. Peloids are structureless grains of microcrystalline carbonate likely produced by a variety of processes. Many are thought to be fecal pellets produced by marine organisms. Others may be produced by endolithic (boring) algae or other microorganisms or through breakdown of mollusc shells. They are difficult to see in
4050-450: A struggle for hegemony between Northumbria and Mercia, which in the 8th century gave way to Mercian preeminence. In the early 9th century Mercia was displaced as the foremost kingdom by Wessex. Later in that century escalating attacks by the Danes culminated in the conquest of the north and east of England, overthrowing the kingdoms of Northumbria, Mercia and East Anglia. Wessex under Alfred
4212-429: A team of divers returned to attempt further exploration. William Frakes and John Ogden were the first to successfully pass the 25-metre (82 ft) sump to reach Skreen Hill 3, 640 metres (2,100 ft) of "magnificent stream passage" ending in boulder choke. In the ensuing months a comprehensive survey was made of all of Marble Arch Caves, including the newly discovered sections. During this time, surveyors learned of
4374-416: Is a type of carbonate sedimentary rock which is the main source of the material lime . It is composed mostly of the minerals calcite and aragonite , which are different crystal forms of CaCO 3 . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as
4536-467: Is also applied to England in a more poetic capacity, though its original meaning is the island of Britain as a whole. The earliest known evidence of human presence in the area now known as England was that of Homo antecessor , dating to about 780,000 years ago. The oldest proto-human bones discovered in England date from 500,000 years ago. Modern humans are known to have inhabited the area during
4698-560: Is also favored on the seaward margin of shelves and platforms, where there is upwelling deep ocean water rich in nutrients that increase organic productivity. Reefs are common here, but when lacking, ooid shoals are found instead. Finer sediments are deposited close to shore. The lack of deep sea limestones is due in part to rapid subduction of oceanic crust, but is more a result of dissolution of calcium carbonate at depth. The solubility of calcium carbonate increases with pressure and even more with higher concentrations of carbon dioxide, which
4860-482: Is an uncommon mineral in limestone, and siderite or other carbonate minerals are rare. However, the calcite in limestone often contains a few percent of magnesium . Calcite in limestone is divided into low-magnesium and high-magnesium calcite, with the dividing line placed at a composition of 4% magnesium. High-magnesium calcite retains the calcite mineral structure, which is distinct from dolomite. Aragonite does not usually contain significant magnesium. Most limestone
5022-402: Is carbonate rock, and most of this is limestone. Limestone is found in sedimentary sequences as old as 2.7 billion years. However, the compositions of carbonate rocks show an uneven distribution in time in the geologic record. About 95% of modern carbonates are composed of high-magnesium calcite and aragonite. The aragonite needles in carbonate mud are converted to low-magnesium calcite within
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5184-474: Is clusters of peloids cemented together by organic material or mineral cement. Extraclasts are uncommon, are usually accompanied by other clastic sediments, and indicate deposition in a tectonically active area or as part of a turbidity current . The grains of most limestones are embedded in a matrix of carbonate mud. This is typically the largest fraction of an ancient carbonate rock. Mud consisting of individual crystals less than 5 μm (0.20 mils) in length
5346-416: Is commonly white to gray in color. Limestone that is unusually rich in organic matter can be almost black in color, while traces of iron or manganese can give limestone an off-white to yellow to red color. The density of limestone depends on its porosity, which varies from 0.1% for the densest limestone to 40% for chalk. The density correspondingly ranges from 1.5 to 2.7 g/cm . Although relatively soft, with
5508-420: Is controlled largely by the amount of dissolved carbon dioxide ( CO 2 ) in the water. This is summarized in the reaction: Increases in temperature or decreases in pressure tend to reduce the amount of dissolved CO 2 and precipitate CaCO 3 . Reduction in salinity also reduces the solubility of CaCO 3 , by several orders of magnitude for fresh water versus seawater. Near-surface water of
5670-545: Is converted to low-magnesium calcite. Diagenesis is the likely origin of pisoliths , concentrically layered particles ranging from 1 to 10 mm (0.039 to 0.394 inches) in diameter found in some limestones. Pisoliths superficially resemble ooids but have no nucleus of foreign matter, fit together tightly, and show other signs that they formed after the original deposition of the sediments. Silicification occurs early in diagenesis, at low pH and temperature, and contributes to fossil preservation. Silicification takes place through
5832-546: Is damp relatively frequently and is changeable. The coldest months are January and February, the latter particularly on the English coast , while July is normally the warmest month. Months with mild to warm weather are May, June, September and October. Rainfall is spread fairly evenly throughout the year. Important influences on the climate of England are its proximity to the Atlantic Ocean , its northern latitude and
5994-503: Is deposited close to where it formed, classification of limestone is usually based on its grain type and mud content. Most grains in limestone are skeletal fragments of marine organisms such as coral or foraminifera . These organisms secrete structures made of aragonite or calcite, and leave these structures behind when they die. Other carbonate grains composing limestones are ooids , peloids , and limeclasts ( intraclasts and extraclasts [ ca ] ). Skeletal grains have
6156-460: Is described as coquinite . Chalk is a soft, earthy, fine-textured limestone composed of the tests of planktonic microorganisms such as foraminifera, while marl is an earthy mixture of carbonates and silicate sediments. Limestone forms when calcite or aragonite precipitate out of water containing dissolved calcium, which can take place through both biological and nonbiological processes. The solubility of calcium carbonate ( CaCO 3 )
6318-617: Is described as micrite . In fresh carbonate mud, micrite is mostly small aragonite needles, which may precipitate directly from seawater, be secreted by algae, or be produced by abrasion of carbonate grains in a high-energy environment. This is converted to calcite within a few million years of deposition. Further recrystallization of micrite produces microspar , with grains from 5 to 15 μm (0.20 to 0.59 mils) in diameter. Limestone often contains larger crystals of calcite, ranging in size from 0.02 to 0.1 mm (0.79 to 3.94 mils), that are described as sparry calcite or sparite . Sparite
6480-462: Is distinguished from micrite by a grain size of over 20 μm (0.79 mils) and because sparite stands out under a hand lens or in thin section as white or transparent crystals. Sparite is distinguished from carbonate grains by its lack of internal structure and its characteristic crystal shapes. Geologists are careful to distinguish between sparite deposited as cement and sparite formed by recrystallization of micrite or carbonate grains. Sparite cement
6642-641: Is governed directly by the Parliament of the United Kingdom , although other countries of the United Kingdom have devolved governments. There has been debate about how to counterbalance this in England. Originally it was planned that various regions of England would be devolved, but following the proposal's rejection by the North East in a 2004 referendum , this has not been carried out. In 2024, an England-only intergovernmental body, known as
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6804-669: Is high moorland in upland areas, indented by fertile valleys of the region's rivers. They contain two national parks , the Yorkshire Dales and the Peak District . In the West Country , Dartmoor and Exmoor of the Southwest Peninsula include upland moorland supported by granite. The English Lowlands are in the central and southern regions of the country, consisting of green rolling hills, including
6966-780: Is known as the lost colony after it was found abandoned on the return of the late-arriving supply ship. With the East India Company , England also competed with the Dutch and French in the East. During the Elizabethan period, England was at war with Spain. An armada sailed from Spain in 1588 as part of a wider plan to invade England and re-establish a Catholic monarchy. The plan was thwarted by bad coordination, stormy weather and successful harrying attacks by an English fleet under Lord Howard of Effingham . This failure did not end
7128-623: Is mostly found in the north and west, including Dartmoor , the Lake District , the Pennines , and the Shropshire Hills . The country's capital is London , the metropolitan area of which has a population of 14.2 million as of 2021, representing the United Kingdom's largest metropolitan area. England's population of 56.3 million comprises 84% of the population of the United Kingdom, largely concentrated around London,
7290-560: Is one of the first minerals to precipitate in marine evaporites. Most limestone is formed by the activities of living organisms near reefs, but the organisms responsible for reef formation have changed over geologic time. For example, stromatolites are mound-shaped structures in ancient limestones, interpreted as colonies of cyanobacteria that accumulated carbonate sediments, but stromatolites are rare in younger limestones. Organisms precipitate limestone both directly as part of their skeletons, and indirectly by removing carbon dioxide from
7452-473: Is otherwise chemically fairly pure, with clastic sediments (mainly fine-grained quartz and clay minerals ) making up less than 5% to 10% of the composition. Organic matter typically makes up around 0.2% of a limestone and rarely exceeds 1%. Limestone often contains variable amounts of silica in the form of chert or siliceous skeletal fragments (such as sponge spicules, diatoms , or radiolarians ). Fossils are also common in limestone. Limestone
7614-562: Is part of the United Kingdom, a constitutional monarchy with a parliamentary system . There has not been a government of England since 1707, when the Acts of Union 1707 , putting into effect the terms of the Treaty of Union , joined England and Scotland to form the Kingdom of Great Britain . Before the union England was ruled by its monarch and the Parliament of England . Today England
7776-472: Is produced by decaying organic matter settling into the deep ocean that is not removed by photosynthesis in the dark depths. As a result, there is a fairly sharp transition from water saturated with calcium carbonate to water unsaturated with calcium carbonate, the lysocline , which occurs at the calcite compensation depth of 4,000 to 7,000 m (13,000 to 23,000 feet). Below this depth, foraminifera tests and other skeletal particles rapidly dissolve, and
7938-518: Is secondary dolomite, formed by chemical alteration of limestone. Limestone is exposed over large regions of the Earth's surface, and because limestone is slightly soluble in rainwater, these exposures often are eroded to become karst landscapes. Most cave systems are found in limestone bedrock. Limestone has numerous uses: as a chemical feedstock for the production of lime used for cement (an essential component of concrete ), as aggregate for
8100-472: Is similar to that of other areas in the British Isles with a wide range of vertebrate and invertebrate life in a diverse range of habitats. National nature reserves in England are designated by Natural England as key places for wildlife and natural features in England. They were established to protect the most significant areas of habitat and of geological formations. NNRs are managed on behalf of
8262-519: The 1535–1542 acts . There were internal religious conflicts during the reigns of Henry's daughters, Mary I and Elizabeth I . The former took the country back to Catholicism while the latter broke from it again, forcefully asserting the supremacy of Anglicanism . The Elizabethan era is the epoch in the Tudor age of the reign of Queen Elizabeth I ("the Virgin Queen"). Historians often depict it as
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#17327759273008424-643: The Age of Discovery . Henry VIII broke from communion with the Catholic Church, over issues relating to his divorce, under the Acts of Supremacy in 1534 which proclaimed the monarch head of the Church of England . In contrast with much of European Protestantism , the roots of the split were more political than theological. He also legally incorporated his ancestral land Wales into the Kingdom of England with
8586-583: The Angeln region of what is now the German state of Schleswig-Holstein . The earliest recorded use of the term, as " Engla londe ", is in the late-ninth-century translation into Old English of Bede 's Ecclesiastical History of the English People . The term was then used to mean "the land inhabited by the English", and it included English people in what is now south-east Scotland but was then part of
8748-590: The Battle of Trafalgar confirmed the naval supremacy Britain had established during the course of the eighteenth century. The Napoleonic Wars fostered a concept of Britishness and a united national British people , shared with the English, Scots and Welsh. London became the largest and most populous metropolitan area in the world during the Victorian era , and trade within the British Empire – as well as
8910-536: The Battle of Watling Street . The author of one study of Roman Britain suggested that from 43 AD to 84 AD, the Roman invaders killed somewhere between 100,000 and 250,000 people from a population of perhaps 2,000,000. This era saw a Greco-Roman culture prevail with the introduction of Roman law , Roman architecture , aqueducts , sewers , many agricultural items and silk. In the 3rd century, Emperor Septimius Severus died at Eboracum (now York ), where Constantine
9072-676: The British Isles , but also from the Commonwealth , particularly the Indian subcontinent . Since the 1970s there has been a large move away from manufacturing and an increasing emphasis on the service industry . As part of the United Kingdom, the area joined a common market initiative called the European Economic Community which became the European Union . Since the late 20th century the administration of
9234-610: The Cotswold Hills , Chiltern Hills , North and South Downs ; where they meet the sea they form white rock exposures such as the cliffs of Dover . This also includes relatively flat plains such as the Salisbury Plain , Somerset Levels , South Coast Plain and The Fens . England has a temperate maritime climate : it is mild with temperatures not much lower than 0 °C (32 °F) in winter and not much higher than 32 °C (90 °F) in summer. The weather
9396-744: The Court of Appeal , the High Court of Justice for civil cases, and the Crown Court for criminal cases. The Supreme Court of the United Kingdom is the highest court for criminal and civil cases in England and Wales . It was created in 2009 after constitutional changes, taking over the judicial functions of the House of Lords . A decision of the Supreme Court is binding on every other court in
9558-583: The Courts of England and Wales continued, under the Treaty of Union , as a separate legal system from the one used in Scotland . The general essence of English law is that it is made by judges sitting in courts, applying their common sense and knowledge of legal precedent – stare decisis – to the facts before them. The court system is headed by the Senior Courts of England and Wales, consisting of
9720-736: The French Revolution , under George III and William Pitt the Younger . The regency of George IV is noted for its elegance and achievements in the fine arts and architecture. During the Napoleonic Wars , Napoleon planned to invade from the south-east ; however, this failed to manifest and the Napoleonic forces were defeated by the British: at sea by Horatio Nelson , and on land by Arthur Wellesley . The major victory at
9882-487: The Kingdom of Great Britain . England is the origin of the English language , the English legal system (which served as the basis for the common law systems of many other countries), association football , and the Anglican branch of Christianity; its parliamentary system of government has been widely adopted by other nations. The Industrial Revolution began in 18th-century England, transforming its society into
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#173277592730010044-735: The Labour Party , 116 from the Conservative Party , 65 from the Liberal Democrats , five for Reform UK and four for the Green Party of England and Wales . The English law legal system, developed over the centuries, is the basis of common law legal systems used in most Commonwealth countries and the United States (except Louisiana ). Despite now being part of the United Kingdom, the legal system of
10206-556: The Latin word Anglii is used. The etymology of the tribal name itself is disputed by scholars; it has been suggested that it derives from the shape of the Angeln peninsula, an angular shape. How and why a term derived from the name of a tribe that was less significant than others, such as the Saxons , came to be used for the entire country is not known, but it seems this is related to
10368-722: The Mayoral Council for England , was established to bring together ministers from the UK Government , the Mayor of London and the leaders of combined authorities . In the House of Commons which is the lower house of the British Parliament based at the Palace of Westminster , there are 543 members of parliament (MPs) for constituencies in England, out of the 650 total. England is represented by 347 MPs from
10530-546: The Ministry of Justice , manages most prisons, housing 81,309 prisoners in England and Wales as of September 2022 . The subdivisions of England consist of up to four levels of subnational division , controlled through a variety of types of administrative entities created for the purposes of local government . Outside the London region, England's highest tier is the 48 ceremonial counties . These are used primarily as
10692-687: The Severn is the longest river flowing through England. It empties into the Bristol Channel and is notable for its Severn Bore (a tidal bore ), which can reach 2 metres (6.6 ft) in height. However, the longest river entirely in England is the Thames, which is 215 miles (346 km) in length. There are many lakes in England ; the largest is Windermere , within the aptly named Lake District . Most of England's landscape consists of low hills and plains, with upland and mountainous terrain in
10854-883: The South East , and conurbations in the Midlands , the North West , the North East , and Yorkshire , which each developed as major industrial regions during the 19th century. The name "England" is derived from the Old English name Englaland , which means "land of the Angles ". The Angles were one of the Germanic tribes that settled in Great Britain during the Early Middle Ages . They came from
11016-479: The State Opening of Parliament by the British monarch when the doors of the House of Commons are slammed in the face of the monarch's messenger, symbolising the rights of Parliament and its independence from the monarch. With the founding of the Royal Society in 1660, science was greatly encouraged. In 1666 the Great Fire of London gutted the city of London, but it was rebuilt shortly afterward with many significant buildings designed by Sir Christopher Wren . By
11178-451: The Stuart dynasty England expanded in trade, finance and prosperity. The Royal Navy developed Europe's largest merchant fleet. After the parliaments of England and Scotland agreed, the two countries joined in political union , to create the Kingdom of Great Britain in 1707. To accommodate the union, institutions such as the law and national churches of each remained separate. Under the newly formed Kingdom of Great Britain, output from
11340-433: The Trinovantes . The Romans invaded Britain in 43 AD during the reign of Emperor Claudius , subsequently conquering much of Britain , and the area was incorporated into the Roman Empire as Britannia province . The best-known of the native tribes who attempted to resist were the Catuvellauni led by Caratacus . Later, an uprising led by Boudica , Queen of the Iceni , ended with Boudica's suicide following her defeat at
11502-441: The UNESCO Earth Sciences division in 2004, the park became part of the Global Network of National Geoparks (GGN) scheme and was renamed Marble Arch Caves Global Geopark . In 2008 the park boundaries were extended across the border into parts of County Cavan in the Republic of Ireland , making it the first international Geopark in the world. The cutting of turf has led to damage in the area. Extensive drainage in parts of
11664-653: The United Kingdom (green) England is a country that is part of the United Kingdom . It is located on the island of Great Britain , of which it covers about 62%, and more than 100 smaller adjacent islands . It has land borders with Scotland to the north and Wales to the west, and is otherwise surrounded by the North Sea to the east, the English Channel to the south, the Celtic Sea to
11826-553: The Upper Paleolithic period, though permanent settlements were only established within the last 6,000 years. After the last ice age only large mammals such as mammoths , bison and woolly rhinoceros remained. Roughly 11,000 years ago, when the ice sheets began to recede, humans repopulated the area; genetic research suggests they came from the northern part of the Iberian Peninsula . The sea level
11988-545: The Yorkshire Ramblers' Club began exploration in the area, and without access to a boat they decided to wade the section of underground river as far as The Junction, subsequently reaching the extent of Martel and Jameson's explorations. Bolstered by the experience, and the good possibility of further discoveries, the Yorkshire Ramblers returned in Easter 1908. A group of cavers descended a pothole located close to
12150-652: The canal age in Britain . In 1825 the world's first permanent steam locomotive-hauled passenger railway – the Stockton and Darlington Railway – opened to the public. During the Industrial Revolution , many workers moved from England's countryside to new and expanding urban industrial areas to work in factories, for instance at Birmingham and Manchester , with the latter the world's first industrial city. England maintained relative stability throughout
12312-496: The decline of the Roman Empire , Britain was left exposed by the end of Roman rule in Britain and the withdrawal of Roman army units, to defend the frontiers in continental Europe and partake in civil wars. Celtic Christian monastic and missionary movements flourished. This period of Christianity was influenced by ancient Celtic culture in its sensibilities, polity, practices and theology. Local "congregations" were centred in
12474-616: The golden age in English history that represented the apogee of the English Renaissance and saw the flowering of great art, drama, poetry, music and literature. England during this period had a centralised, well-organised, and effective government. Competing with Spain , the first English colony in the Americas was founded in 1585 by explorer Walter Raleigh in Virginia and named Roanoke . The Roanoke colony failed and
12636-548: The jet engine led to wider air travel . Residential patterns were altered in England by private motoring, and by the creation of the National Health Service in 1948, providing publicly funded health care to all permanent residents free at the point of need. Combined, these prompted the reform of local government in England in the mid-20th century. Since the 20th century, there has been significant population movement to England, mostly from other parts of
12798-485: The plateau above the end of Cladagh Glen were all known well before underground exploration began; in fact the arch was a popular tourist attraction in the 19th century. As early as the 1730s, the Reverend William Henry described these features, as well as the sinks of the Owenbrean, Aghinrawn and Sruh Croppa rivers which he correctly surmised to be feeders of the system. Without venturing far into
12960-642: The 32 London Boroughs and the 25 Wards of the City of London . Geographically, England includes the central and southern two-thirds of the island of Great Britain, plus such offshore islands as the Isle of Wight and the Isles of Scilly . It is bordered by two other countries of the United Kingdom: to the north by Scotland and to the west by Wales. England is closer than any other part of mainland Britain to
13122-435: The 5th and 6th centuries. England became a unified state in the 10th century and has had extensive cultural and legal impact on the wider world since the Age of Discovery , which began during the 15th century. The Kingdom of England , which included Wales after 1535, ceased to be a separate sovereign state on 1 May 1707, when the Acts of Union brought into effect a political union with the Kingdom of Scotland that created
13284-575: The 6th century. Contemporary texts describing this period are extremely scarce, giving rise to its description as a Dark Age . Details of the Anglo-Saxon settlement of Britain are consequently subject to considerable disagreement; the emerging consensus is that it occurred on a large scale in the south and east but was less substantial to the north and west, where Celtic languages continued to be spoken even in areas under Anglo-Saxon control. Roman-dominated Christianity had, in general, been replaced in
13446-650: The Cladagh. On the surface, the river emerges from the largest karst resurgence in Ireland, and one of the largest in the United Kingdom . At 11.5 kilometres (7.1 mi) the Marble Arch Caves form the longest known cave system in Northern Ireland, and the karst is considered to be among the finest in the British Isles . The Marble Arch, Cladagh River resurgence and three large dolines on
13608-496: The Earth's history. Limestone may have been deposited by microorganisms in the Precambrian , prior to 540 million years ago, but inorganic processes were probably more important and likely took place in an ocean more highly oversaturated in calcium carbonate than the modern ocean. Diagenesis is the process in which sediments are compacted and turned into solid rock . During diagenesis of carbonate sediments, significant chemical and textural changes take place. For example, aragonite
13770-676: The English kingdom of Northumbria . The Anglo-Saxon Chronicle recorded that the Domesday Book of 1086 covered the whole of England, meaning the English kingdom, but a few years later the Chronicle stated that King Malcolm III went "out of Scotlande into Lothian in Englaland", thus using it in the more ancient sense. The earliest attested reference to the Angles occurs in the 1st-century work by Tacitus , Germania , in which
13932-591: The European continent. It is separated from France ( Hauts-de-France ) by a 21-mile (34 km) sea gap, though the two countries are connected by the Channel Tunnel near Folkestone . England also has shores on the Irish Sea , North Sea and Atlantic Ocean. The ports of London, Liverpool , and Newcastle lie on the tidal rivers Thames , Mersey and Tyne respectively. At 220 miles (350 km),
14094-509: The Great was left as the only surviving English kingdom, and under his successors, it steadily expanded at the expense of the kingdoms of the Danelaw . This brought about the political unification of England, first accomplished under Æthelstan in 927 and definitively established after further conflicts by Eadred in 953. A fresh wave of Scandinavian attacks from the late 10th century ended with
14256-602: The North, and the successful Norman Conquest in October 1066, accomplished by an army led by Duke William of Normandy invading at Hastings late September 1066. The Normans themselves originated from Scandinavia and had settled in Normandy in the late 9th and early 10th centuries. This conquest led to the almost total dispossession of the English elite and its replacement by a new French-speaking aristocracy, whose speech had
14418-603: The Owenbrean River upstream of its main sink at Pollasumera; and most notably Goat Pot, Aghatirourke Pot, Pigeon Pots and Badger Pot on East Cuilcagh, nearly 3 kilometres (1.9 mi) to the southeast. Of these, Goat Pot and Aghatirourke Pot have also been traced to Tullyhona Rising (1.5 kilometres (0.93 mi) east-southeast from Cascades Rising); Pigeon Pots, Badger Pot and Aghatirourke Pot also flow to Gortalughany Rising (an overflow rising on East Cuilcagh); and Badger Pot and Pigeon Pots also flow to Shannon Pot on
14580-682: The Pope. During the 14th century, the Plantagenets and the House of Valois claimed to be legitimate claimants to the House of Capet and of France; the two powers clashed in the Hundred Years' War . The Black Death epidemic hit England ; starting in 1348, it eventually killed up to half of England's inhabitants . Between 1453 and 1487, a civil war known as the War of the Roses waged between
14742-943: The Royal Society and other English initiatives combined with the Scottish Enlightenment to create innovations in science and engineering, while the enormous growth in British overseas trade protected by the Royal Navy paved the way for the establishment of the British Empire . Domestically it drove the Industrial Revolution , a period of profound change in the socioeconomic and cultural conditions of England, resulting in industrialised agriculture, manufacture, engineering and mining, as well as new and pioneering road, rail and water networks to facilitate their expansion and development. The opening of Northwest England's Bridgewater Canal in 1761 ushered in
14904-644: The Sruh Croppa, the Aghinrawn (or Monastir) and the Owenbrean . The Prod's Pot – Cascades Rising section of the system (connected to Marble Arch Caves in 2009) has a complex hydrology which includes drainage from at least five small sinks on the eastern Marlbank (Gortmaconnell Pot, Little Gortmaconnell Pot, Smokey Mountain Sink and two unnamed sinks at Brookfield have been dye traced to Cascades); sections of
15066-432: The United Kingdom has moved towards devolved governance in Scotland, Wales and Northern Ireland. England and Wales continues to exist as a jurisdiction within the United Kingdom. Devolution has stimulated a greater emphasis on a more English-specific identity and patriotism. There is no devolved English government, but an attempt to create a similar system on a sub-regional basis was rejected by referendum . England
15228-607: The United Kingdom as part of the Allies . Two decades later, in World War II , the United Kingdom was again one of the Allies . Developments in warfare technology saw many cities damaged by air-raids during the Blitz . Following the war, the British Empire experienced rapid decolonisation , and there was a speeding-up of technological innovations; automobiles became the primary means of transport and Frank Whittle 's development of
15390-430: The accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite , a closely related rock, which contains
15552-577: The area, the Beaker culture people made bronze , and later iron from iron ores. The development of iron smelting allowed the construction of better ploughs , advancing agriculture (for instance, with Celtic fields ), as well as the production of more effective weapons. During the Iron Age , Celtic culture , deriving from the Hallstatt and La Tène cultures , arrived from Central Europe. Brythonic
15714-767: The auspices of James VI and I the Authorised King James Version of the Holy Bible was published in 1611. It was the standard version of the Bible read by most Protestant Christians for four hundred years until modern revisions were produced in the 20th century. Based on conflicting political, religious and social positions, the English Civil War was fought between the supporters of Parliament and those of King Charles I , known colloquially as Roundheads and Cavaliers respectively. This
15876-434: The base of roads, as white pigment or filler in products such as toothpaste or paint, as a soil conditioner , and as a popular decorative addition to rock gardens . Limestone formations contain about 30% of the world's petroleum reservoirs . Limestone is composed mostly of the minerals calcite and aragonite , which are different crystal forms of calcium carbonate ( CaCO 3 ). Dolomite , CaMg(CO 3 ) 2 ,
16038-657: The beds. This may include the formation of vugs , which are crystal-lined cavities within the limestone. Diagenesis may include conversion of limestone to dolomite by magnesium-rich fluids. There is considerable evidence of replacement of limestone by dolomite, including sharp replacement boundaries that cut across bedding. The process of dolomitization remains an area of active research, but possible mechanisms include exposure to concentrated brines in hot environments ( evaporative reflux ) or exposure to diluted seawater in delta or estuary environments ( Dorag dolomitization ). However, Dorag dolomitization has fallen into disfavor as
16200-432: The bog has damaged the bog's ability to retain water, resulting in flooding and abnormally high water levels in the caves downstream. This has impeded tourist activity in the past, notably in 1989 when the impact of such damage influencing cave water levels first became evident. As a protective measure, turf cutting has been banned within the wider Geopark. In addition more than 1200 small dams have been put in place across
16362-412: The bogland to slow water flow and encourage the growth of new bog. Another problem is that human interference can cause the limestone to be damaged or eroded . In a particular case in 1984, a group of vandals broke into the show cave before it was opened to the public and threw stones at some of the calcite formations around the entrance. Many small stalactites were snapped off at their bases, while
16524-566: The bottom with the concave face downwards. This traps a void space that can later be filled by sparite. Geologists use geopetal structures to determine which direction was up at the time of deposition, which is not always obvious with highly deformed limestone formations. The cyanobacterium Hyella balani can bore through limestone; as can the green alga Eugamantia sacculata and the fungus Ostracolaba implexa . England – in Europe (green & dark grey) – in
16686-422: The cave, Henry descended to the base of one of the dolines above the resurgence: The arch over my head was 20 feet high, continued with a little landing for 100 yards to the other great pit, by the light of which I could observe the river flowing gently along... The stream passages at the base of each shakehole were first explored by Édouard-Alfred Martel and Dublin naturalist Lyster Jameson in 1895. Using
16848-634: The caves and the nearby Cuilcagh Mountain Park joined to become a European Geopark under the name Marble Arch Caves European Geopark, the first park in the UK to be recognised by the European Geoparks Network (EGN). This allocation was due in part to the existence of the caves themselves and also the rare blanket bog which covers a vast area of the mountains. Under an agreement between the EGN and
17010-427: The caves by the same route that Martel and the early explorers took. The development also included boring a new entrance shaft into Skreen Hill and, significantly, excavating a corridor using quarrymens' plugs and feathers (instead of potentially damaging explosives) through the short section of rock separating Pool Chamber from New Chamber. This connected Skreen Hill all the way to The Junction for walking visitors for
17172-585: The conquered territories by Anglo-Saxon paganism , but was reintroduced by missionaries from Rome led by Augustine from 597. Disputes between the Roman- and Celtic-dominated forms of Christianity ended in victory for the Roman tradition at the Council of Whitby (664), which was ostensibly about tonsures (clerical haircuts) and the date of Easter, but more significantly, about the differences in Roman and Celtic forms of authority, theology, and practice. During
17334-541: The conquest of this united kingdom by Sweyn Forkbeard in 1013 and again by his son Cnut in 1016, turning it into the centre of a short-lived North Sea Empire that also included Denmark and Norway . However, the native royal dynasty was restored with the accession of Edward the Confessor in 1042. A dispute over the succession to Edward led to an unsuccessful Norwegian Invasion in September 1066 close to York in
17496-454: The course of the fifth and sixth centuries, initially in the eastern part of the country. Their advance was contained for some decades after the Britons' victory at the Battle of Mount Badon , but subsequently resumed, overrunning the fertile lowlands of Britain and reducing the area under Brittonic control to a series of separate enclaves in the more rugged country to the west by the end of
17658-883: The custom of calling the Germanic people in Britain Angli Saxones or English Saxons to distinguish them from continental Saxons (Eald-Seaxe) of Old Saxony in Germany. In Scottish Gaelic , the Saxon tribe gave their name to the word for England ( Sasunn ); similarly, the Welsh name for the English language is Saesneg . A romantic name for England is Loegria , related to the Welsh word for England, Lloegr , and made popular by its use in Arthurian legend . Albion
17820-709: The deaths of Frakes, Ogden and Colin Vickers—another of the divers in the original team—in the Mossdale Caverns accident. In tribute, a number of cave features in Skreen Hill 3 were named after the three cavers. From 1982 until after opening in 1985, sections of Marble Arch Cave underwent development to improve accessibility in order to accept tourist visitors. As well as concrete pathways, safety barriers and electric lighting, this involved installing weirs and jetties for boat access to enable visitors to enter
17982-466: The depositional fabric of carbonate rocks. Dunham divides the rocks into four main groups based on relative proportions of coarser clastic particles, based on criteria such as whether the grains were originally in mutual contact, and therefore self-supporting, or whether the rock is characterized by the presence of frame builders and algal mats. Unlike the Folk scheme, Dunham deals with the original porosity of
18144-469: The deposits are highly porous, so that they have a spongelike texture, they are typically described as tufa . Secondary calcite deposited by supersaturated meteoric waters ( groundwater ) in caves is also sometimes described as travertine. This produces speleothems , such as stalagmites and stalactites . Coquina is a poorly consolidated limestone composed of abraded pieces of coral , shells , or other fossil debris. When better consolidated, it
18306-411: The disaster, and the entrance remains accessible to cavers via a gate. Three oak saplings were also planted on the grassy area south of the car park by each of the families on the tenth anniversary of the accident. In 2009 and 2010 diving connections were made to nearby cave systems by Artur Kozłowski . Kozłowski made the first connecting dive to Prod's Pot – Cascades Rising, doubling the total length of
18468-438: The dive however, they investigated a small dry passage leading off on the left bank of the lake, finding it to be blocked at the end by unstable boulders in the roof. The cavers removed one of the boulders to reveal a way on, which led via a dry route to the far side of Sump 1. The new 200-metre (660 ft) section of river passage beyond was named Skreen Hill 2, and a further 800-metre ( 1 ⁄ 2 mi) inlet passage
18630-637: The early 2010s England was divided for a few purposes into regions; a 1998 referendum for the London Region created the London Assembly two years later. A failed 2004 North East England devolution referendum cancelled further regional assembly devolution with the regional structure outside London abolished. Ceremonially and administratively, the region is divided between the City of London and Greater London ; these are further divided into
18792-406: The earth's oceans are oversaturated with CaCO 3 by a factor of more than six. The failure of CaCO 3 to rapidly precipitate out of these waters is likely due to interference by dissolved magnesium ions with nucleation of calcite crystals, the necessary first step in precipitation. Precipitation of aragonite may be suppressed by the presence of naturally occurring organic phosphates in
18954-429: The entrance found in 1908, and after some investigation discovered a high-level crawling passage exiting the chamber. The passage ended high in the wall of New Chamber, a cavern of considerable size, where the upstream continuation of the river was found. Exploration was halted here as the water was too deep to pass. The club returned to New Chamber in 1936 to explore and survey the ongoing Skreen Hill passage, named after
19116-403: The far western slopes of Cuilcagh. Édouard-Alfred Martel first postulated that Marble Arch Cave would make a worthy show cave after initially exploring the system in 1895. However it was not until 1982 that work eventually began on creating a new underground tourist attraction . Development included: Covering a section of the main stream passage of the system, the Marble Arch Caves show cave
19278-399: The first refers to the grains and the second to the cement. For example, a limestone consisting mainly of ooids, with a crystalline matrix, would be termed an oosparite. It is helpful to have a petrographic microscope when using the Folk scheme, because it is easier to determine the components present in each sample. Robert J. Dunham published his system for limestone in 1962. It focuses on
19440-535: The first time. At this time, all known entrances to the cave system were gated to control access. From then on, cavers were only allowed access by agreement with show cave management. The show cave has since become established as a popular tourist attraction. Three cavers died on a trip into Lower Cradle Hole on 15 January 1995. They were in a group of ten cavers, mostly students from University College Dublin and Dublin Institute of Technology caving clubs, when
19602-572: The formation of distinctive minerals from the silica and clay present in the original limestone. Two major classification schemes, the Folk and Dunham, are used for identifying the types of carbonate rocks collectively known as limestone. Robert L. Folk developed a classification system that places primary emphasis on the detailed composition of grains and interstitial material in carbonate rocks . Based on composition, there are three main components: allochems (grains), matrix (mostly micrite), and cement (sparite). The Folk system uses two-part names;
19764-429: The geologic record are called bioherms . Many are rich in fossils, but most lack any connected organic framework like that seen in modern reefs. The fossil remains are present as separate fragments embedded in ample mud matrix. Much of the sedimentation shows indications of occurring in the intertidal or supratidal zones, suggesting sediments rapidly fill available accommodation space in the shelf or platform. Deposition
19926-538: The hierarchy, which must follow its directions. The Secretary of State for Justice is the minister responsible to Parliament for the judiciary , the court system and prisons and probation in England. Crime increased between 1981 and 1995 but fell by 42% in the period 1995–2006. The prison population doubled over the same period, giving it one of the highest incarceration rates in Western Europe at 147 per 100,000. His Majesty's Prison Service , reporting to
20088-409: The hill on the surface above. After 370 metres (1,200 ft) of walking passage, the cavers stopped at a deep lake . This section of deep water is where the path of the current show cave ends. When club members returned again in 1938 they brought an inflatable dinghy , allowing them to progress across the lake, only to discover that the way on was blocked by Sump 1, just 40 metres (132 ft) from
20250-500: The large dolines on the plateau and discovered the Great Boulder Chamber. After a few hours of exploring, they realised that they had found a new route into Pool Chamber, bypassing the deep water of the original entrance. During the 1908 explorations, the Yorkshire Ramblers conducted tests to ascertain the hydrological connections between caves. They performed a dye tracing experiment with fluorescein , establishing
20412-453: The metropolitan counties have different types of status to other ceremonial counties. The second tier is made up of combined authorities and the 27 county-tier shire counties . In 1974, all ceremonial counties were two-tier; and with the metropolitan county tier phased out, the 1996 reform separated the ceremonial county and the administrative county tier. England is also divided into local government districts. The district can align to
20574-707: The mid-to-late 17th century, two political factions had emerged – the Tories and Whigs . Though the Tories initially supported Catholic king James II , some of them, along with the Whigs, during the Revolution of 1688 invited the Dutch Prince William of Orange to defeat James and become the king. Some English people, especially in the north, were Jacobites and continued to support James and his sons. Under
20736-569: The monastic community and monastic leaders were more like chieftains, as peers, rather than in the more hierarchical system of the Roman-dominated church. Roman military withdrawals left Britain open to invasion by pagan, seafaring warriors from north-western continental Europe, chiefly the Saxons, Angles , Jutes and Frisians who had long raided the coasts of the Roman province. These groups then began to settle in increasing numbers over
20898-611: The nation, many by Natural England themselves, but also by non-governmental organisations, including the members of The Wildlife Trusts partnership, the National Trust , and the Royal Society for the Protection of Birds . There are 221 NNRs in England covering 110,000 hectares (1,100 square kilometres). Often they contain rare species or nationally important populations of plants and animals. . The Environment Agency
21060-613: The north and west of the country. The northern uplands include the Pennines , a chain of uplands dividing east and west, the Lake District mountains in Cumbria, and the Cheviot Hills , straddling the border between England and Scotland. The highest point in England, at 978 metres (3,209 ft), is Scafell Pike in the Lake District. The Shropshire Hills are near Wales while Dartmoor and Exmoor are two upland areas in
21222-410: The ocean basins, but limestone is rarely preserved in continental slope and deep sea environments. The best environments for deposition are warm waters, which have both a high organic productivity and increased saturation of calcium carbonate due to lower concentrations of dissolved carbon dioxide. Modern limestone deposits are almost always in areas with very little silica-rich sedimentation, reflected in
21384-487: The passages were connected; subsequently, two of the party swam through to make the first through-trip between Marble Arch Cave and Lower Cradle Hole Cave. By the mid-1960s a number of advancements had been made in cave diving , by which method speleologists had extended their explorations into caves beyond the sumps that would normally have halted progress. In December 1966 divers Dave Cobley and Mike Boon made preparations to dive Sump 1 in Skreen Hill passage. Before making
21546-426: The reaction: Fossils are often preserved in exquisite detail as chert. Cementing takes place rapidly in carbonate sediments, typically within less than a million years of deposition. Some cementing occurs while the sediments are still under water, forming hardgrounds . Cementing accelerates after the retreat of the sea from the depositional environment, as rainwater infiltrates the sediment beds, often within just
21708-482: The relative purity of most limestones. Reef organisms are destroyed by muddy, brackish river water, and carbonate grains are ground down by much harder silicate grains. Unlike clastic sedimentary rock, limestone is produced almost entirely from sediments originating at or near the place of deposition. Limestone formations tend to show abrupt changes in thickness. Large moundlike features in a limestone formation are interpreted as ancient reefs , which when they appear in
21870-460: The rock. The Dunham scheme is more useful for hand samples because it is based on texture, not the grains in the sample. A revised classification was proposed by Wright (1992). It adds some diagenetic patterns to the classification scheme. Travertine is a term applied to calcium carbonate deposits formed in freshwater environments, particularly waterfalls , cascades and hot springs . Such deposits are typically massive, dense, and banded. When
22032-479: The sediments increases. Chemical compaction takes place by pressure solution of the sediments. This process dissolves minerals from points of contact between grains and redeposits it in pore space, reducing the porosity of the limestone from an initial high value of 40% to 80% to less than 10%. Pressure solution produces distinctive stylolites , irregular surfaces within the limestone at which silica-rich sediments accumulate. These may reflect dissolution and loss of
22194-662: The sediments of the ocean floor abruptly transition from carbonate ooze rich in foraminifera and coccolith remains ( Globigerina ooze) to silicic mud lacking carbonates. In rare cases, turbidites or other silica-rich sediments bury and preserve benthic (deep ocean) carbonate deposits. Ancient benthic limestones are microcrystalline and are identified by their tectonic setting. Fossils typically are foraminifera and coccoliths. No pre-Jurassic benthic limestones are known, probably because carbonate-shelled plankton had not yet evolved. Limestones also form in freshwater environments. These limestones are not unlike marine limestone, but have
22356-450: The settlement period the lands ruled by the incomers seem to have been fragmented into numerous tribal territories, but by the 7th century, when substantial evidence of the situation again becomes available, these had coalesced into roughly a dozen kingdoms including Northumbria , Mercia , Wessex , East Anglia , Essex , Kent and Sussex . Over the following centuries, this process of political consolidation continued. The 7th century saw
22518-420: The shore. During the 1935 expedition another group of cavers explored Lower Cradle Hole Cave. On reaching the downstream end of the cave, they discovered that water levels were now low enough to see a series of low arches above the water surface. By anchoring a floating candle part-way through the passage, exiting the cave and returning to the end of the Grand Gallery in Marble Arch Cave, the cavers confirmed that
22680-422: The signing of Magna Carta , an English legal charter used to limit the sovereign's powers by law and protect the privileges of freemen. Catholic monasticism flourished, providing philosophers, and the universities of Oxford and Cambridge were founded with royal patronage. The Principality of Wales became a Plantagenet fief during the 13th century and the Lordship of Ireland was given to the English monarchy by
22842-524: The south-west of the country. The approximate dividing line between terrain types is often indicated by the Tees–Exe line . The Pennines, known as the "backbone of England", are the oldest range of mountains in the country, originating from the end of the Paleozoic Era around 300 million years ago. Their geological composition includes, among others, sandstone and limestone , and also coal. There are karst landscapes in calcite areas such as parts of Yorkshire and Derbyshire . The Pennine landscape
23004-403: The south-west, and the Irish Sea to the west. Continental Europe lies to the south-east, and Ireland to the west. At the 2021 census , the population was 56,490,048. London is both the largest city and the capital . The area now called England was first inhabited by modern humans during the Upper Paleolithic . It takes its name from the Angles , a Germanic tribe who settled during
23166-436: The standing of the British military and navy – was prestigious. Technologically, this era saw many innovations that proved key to the United Kingdom's power and prosperity. Political agitation at home from radicals such as the Chartists and the suffragettes enabled legislative reform and universal suffrage . Power shifts in east-central Europe led to World War I; hundreds of thousands of English soldiers died fighting for
23328-469: The system from 4.5 to 9 km (2.8 to 5.6 mi). Subsequently he and Chris Jewell connected the newly established Monastir Sink – Upper Cradle system, extending the Marble Arch system to 11.5 km (7.1 mi). The discoveries make this the longest cave in Northern Ireland. The Marble Arch Cave system is chiefly formed from three rivers which drain off the Marlbank area on the north side of Cuilcagh mountain. From west to east, these tributaries are
23490-441: The threat: Spain launched two further armadas, in 1596 and 1597 , but both were driven back by storms. The political structure of the island changed in 1603, when the King of Scots , James VI , a kingdom which had been a long-time rival to English interests, inherited the throne of England as James I, thereby creating a personal union . He styled himself King of Great Britain , although this had no basis in English law. Under
23652-399: The three were swept away by fast running water and drowned in the low air-space (or "duck", (which was flooded to the roof on this particular occasion) section of passage between the end of Lower Cradle Hole and the Grand Gallery in Marble Arch Cave. Those killed were Philip Marshall (20), Brian Patrick Kennedy (22) and Conleth Cormican (21). A memorial plaque outside Lower Cradle commemorates
23814-574: The tip of the largest stalactite in the show cave (over 2 metres [6.6 ft] in length) was broken off. This tip fell onto a sandbank on the cave floor where it was retrieved the next day by a workman. It was then sent to the Ulster Museum in Belfast where a calcite resin was specially produced and subsequently used to stick the tip back onto its original position. 54°15′30.34″N 7°48′51.53″W / 54.2584278°N 7.8143139°W / 54.2584278; -7.8143139 Limestone Limestone ( calcium carbonate CaCO 3 )
23976-473: The two branches of the royal family, the Yorkists and Lancastrians . Eventually it led to the Yorkists losing the throne entirely to a Welsh noble family the Tudors , a branch of the Lancastrians headed by Henry Tudor who invaded with Welsh and Breton mercenaries, gaining victory at the Battle of Bosworth Field where the Yorkist king Richard III was killed. During the Tudor period , England began to develop naval skills , and exploration intensified in
24138-401: The walking section of the show cave. Martel and Jameson also investigated Cradle Hole, a very large surface shakehole 400 metres ( 1 ⁄ 4 mi) south-south-west of Marble Arch. A cave entrance in the north-eastern corner—Lower Cradle—was explored, reaching an underground river and passages with the same proportions as those in the Marble Arch Cave. In 1907, English cavers from
24300-428: The warming of the sea by the Gulf Stream . Rainfall is higher in the west, and parts of the Lake District receive more rain than anywhere else in the country. Since weather records began, the highest temperature recorded was 40.3 °C (104.5 °F) on 19 July 2022 at Coningsby , Lincolnshire , while the lowest was −26.1 °C (−15.0 °F) on 10 January 1982 in Edgmond , Shropshire. The fauna of England
24462-533: The water by photosynthesis and thereby decreasing the solubility of calcium carbonate. Limestone shows the same range of sedimentary structures found in other sedimentary rocks. However, finer structures, such as lamination , are often destroyed by the burrowing activities of organisms ( bioturbation ). Fine lamination is characteristic of limestone formed in playa lakes , which lack the burrowing organisms. Limestones also show distinctive features such as geopetal structures , which form when curved shells settle to
24624-553: The water. Although ooids likely form through purely inorganic processes, the bulk of CaCO 3 precipitation in the oceans is the result of biological activity. Much of this takes place on carbonate platforms . The origin of carbonate mud, and the processes by which it is converted to micrite, continue to be a subject of research. Modern carbonate mud is composed mostly of aragonite needles around 5 μm (0.20 mils) in length. Needles of this shape and composition are produced by calcareous algae such as Penicillus , making this
24786-425: The world's first industrialised nation. England is home to the two oldest universities in the English-speaking world: the University of Oxford , founded in 1096, and the University of Cambridge , founded in 1209. Both universities are ranked among the most prestigious in the world. England's terrain chiefly consists of low hills and plains , especially in the centre and south . Upland and mountainous terrain
24948-453: Was an interwoven part of the wider multifaceted Wars of the Three Kingdoms , involving Scotland and Ireland . The Parliamentarians were victorious, Charles I was executed and the kingdom replaced by the Commonwealth . Leader of the Parliament forces, Oliver Cromwell declared himself Lord Protector in 1653; a period of personal rule followed. After Cromwell's death and the resignation of his son Richard as Lord Protector, Charles II
25110-401: Was established with the Bill of Rights in 1689. Among the statutes set down were that the law could only be made by Parliament and could not be suspended by the King, also that the King could not impose taxes or raise an army without the prior approval of Parliament. Also since that time, no British monarch has entered the House of Commons when it is sitting, which is annually commemorated at
25272-399: Was invited to return as monarch in 1660, in a move called the Restoration . With the reopening of theatres, fine arts, literature and performing arts flourished throughout the Restoration of the "Merry Monarch" Charles II. After the Glorious Revolution of 1688, it was constitutionally established that King and Parliament should rule together, though Parliament would have the real power. This
25434-416: Was likely deposited in pore space between grains, suggesting a high-energy depositional environment that removed carbonate mud. Recrystallized sparite is not diagnostic of depositional environment. Limestone outcrops are recognized in the field by their softness (calcite and aragonite both have a Mohs hardness of less than 4, well below common silicate minerals) and because limestone bubbles vigorously when
25596-572: Was lower than the present day and Britain was connected by land bridge to Ireland and Eurasia . As the seas rose, it was separated from Ireland 10,000 years ago and from Eurasia two millennia later. The Beaker culture arrived around 2,500 BC, introducing drinking and food vessels constructed from clay, as well as vessels used as reduction pots to smelt copper ores. It was during this time that major Neolithic monuments such as Stonehenge (phase III) and Avebury were constructed. By heating together tin and copper, which were in abundance in
25758-406: Was named Legnabrocky Way. A notable feature of the Legnabrocky Way is the Giant's Hall, a large chamber 60 m long, 30 m high and 15 m wide (200×98×49 ft). Despite only carrying a small stream, the Legnabrocky Way is the largest section of passage in Marble Arch Cave. The upstream continuation of the river in Skreen Hill 2 was found to be shortly blocked by Sump 3, so in March 1967
25920-406: Was opened to the public on 29 May 1985. Visitors travel through the first part of the caves by boat on the subterranean Cladagh River, before walking through the rest of the chambers. Between 1985 and 2008 the show cave attracted approximately 1 million visitors, from 100 countries worldwide. Annual visitor capacity (during the period that the cave is open, March–September) is 94,060. In 2001,
26082-568: Was subsequently proclaimed emperor a century later. There is debate about when Christianity was first introduced; it was no later than the 4th century, probably much earlier. According to Bede , missionaries were sent from Rome by Eleutherius at the request of the chieftain Lucius of Britain in 180 AD, to settle differences as to Eastern and Western ceremonials, which were disturbing the church. There are traditions linked to Glastonbury claiming an introduction through Joseph of Arimathea , while others claim through Lucius of Britain. By 410, during
26244-401: Was the spoken language during this time. Society was tribal; according to Ptolemy 's Geographia there were around 20 tribes in the area. Like other regions on the edge of the Empire, Britain had long enjoyed trading links with the Romans. Julius Caesar of the Roman Republic attempted to invade twice in 55 BC; although largely unsuccessful, he managed to set up a client king from
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