Misplaced Pages

#556443

93-713: The William Girling Reservoir is located in the London Borough of Enfield and is part of the Lee Valley Reservoir Chain that supplies London with drinking water. It is named after William Girling OBE, a chairman of the Metropolitan Water Board (MWB). The reservoir and the nearby King George V Reservoir are known collectively as the Chingford Reservoirs . The storage reservoir, which is owned by Thames Water ,

186-457: A grade II listed art deco factory building can be found along Southbury Road, with the former Ripaults Factory , now an office building for Travis Perkins . The area of the modern borough broadly corresponds to the two ancient parishes of Enfield and Edmonton, and was historically part of the county of Middlesex . Both parishes were made local board districts in 1850, each with an elected board overseeing public health and responsible for

279-563: A basaltic magma to a granitic magma, but the quantities produced are small. For example, granitic rock makes up just 4% of the exposures in the South Sandwich Islands . In continental arc settings, granitic rocks are the most common plutonic rocks, and batholiths composed of these rock types extend the entire length of the arc. There are no indication of magma chambers where basaltic magmas differentiate into granites, or of cumulates produced by mafic crystals settling out of

372-520: A diapir it would expend far too much energy in heating wall rocks, thus cooling and solidifying before reaching higher levels within the crust. Fracture propagation is the mechanism preferred by many geologists as it largely eliminates the major problems of moving a huge mass of magma through cold brittle crust. Magma rises instead in small channels along self-propagating dykes which form along new or pre-existing fracture or fault systems and networks of active shear zones. As these narrow conduits open,

465-610: A granite that is derived from partial melting of metasedimentary rocks may have more alkali feldspar, whereas a granite derived from partial melting of metaigneous rocks may be richer in plagioclase. It is on this basis that the modern "alphabet" classification schemes are based. The letter-based Chappell & White classification system was proposed initially to divide granites into I-type (igneous source) granite and S-type (sedimentary sources). Both types are produced by partial melting of crustal rocks, either metaigneous rocks or metasedimentary rocks. I-type granites are characterized by

558-592: A ground in the borough when they merged with Brimsdown Rovers for the start of the 2011/2012 season. Saracens Rugby Football Club used to play in Enfield and still train at Bramley Road sports ground near Cockfosters . The principal cricket clubs in the area are Enfield, Winchmore Hill Cricket Club , Edmonton and Southgate, with many others playing cricket in and around the borough such as, Enfield Invicta, Mayfield CC, Myddleton House, North Enfield CC , Botany Bay and Holtwhites Trinibis CC. Many clubs play in either

651-565: A high content of sodium and calcium, and by a strontium isotope ratio, Sr/ Sr, of less than 0.708. Sr is produced by radioactive decay of Rb, and since rubidium is concentrated in the crust relative to the mantle, a low ratio suggests origin in the mantle. The elevated sodium and calcium favor crystallization of hornblende rather than biotite. I-type granites are known for their porphyry copper deposits. I-type granites are orogenic (associated with mountain building) and usually metaluminous. S-type granites are sodium-poor and aluminum-rich. As

744-476: A higher attendance, appliances from throughout London can be mobilised to meet the needs of the area if required. The three fire stations operate a total of five pumping appliances, one rescue tender, a command unit and a USAR unit. Of the three fire stations within the borough, Enfield is mobilised to the most incidents and has the largest station ground (the area of which Enfield is the first appliance to attend). The borough's museums include Forty Hall and

837-625: A history of armaments manufacture—see Royal Small Arms Factory . The Lee–Enfield .303 rifle was standard issue for the British Army until 1957, although its usage carried on afterwards for some time. Other firearms manufactured there include the Bren and Sten machine guns—the "en" in both cases denoting the place of manufacture. The world's first solid state circuitry colour televisions were manufactured by Ferguson at their now closed plant in Enfield. The first mass-produced dishwasher

930-824: A much higher proportion of clay with the Cecil soil series a prime example of the consequent Ultisol great soil group. Granite is a natural source of radiation , like most natural stones. Potassium-40 is a radioactive isotope of weak emission, and a constituent of alkali feldspar , which in turn is a common component of granitic rocks, more abundant in alkali feldspar granite and syenites . Some granites contain around 10 to 20 parts per million (ppm) of uranium . By contrast, more mafic rocks, such as tonalite, gabbro and diorite , have 1 to 5 ppm uranium, and limestones and sedimentary rocks usually have equally low amounts. Many large granite plutons are sources for palaeochannel -hosted or roll front uranium ore deposits , where

1023-485: A new leisure centre, a supermarket, and many other civic features. Many local activities are located around the A10 road , on the sites of former industrial enterprises, which has a number of large retail outlets and a large multiplex Cineworld cinema. The cinema also hosts Jubilee Church on a Sunday morning; whilst cinemagoers continue to watch films in the other screens, a charismatic church which draws its worshippers from

SECTION 10

#1732791028557

1116-536: A peculiar mineralogy and geochemistry, with particularly high silicon and potassium at the expense of calcium and magnesium and a high content of high field strength cations (cations with a small radius and high electrical charge, such as zirconium , niobium , tantalum , and rare earth elements .) They are not orogenic, forming instead over hot spots and continental rifting, and are metaluminous to mildly peralkaline and iron-rich. These granites are produced by partial melting of refractory lithology such as granulites in

1209-568: A range of hills, formed by the metamorphic aureole or hornfels . Granite often occurs as relatively small, less than 100 km stock masses ( stocks ) and in batholiths that are often associated with orogenic mountain ranges. Small dikes of granitic composition called aplites are often associated with the margins of granitic intrusions . In some locations, very coarse-grained pegmatite masses occur with granite. Granite forms from silica-rich ( felsic ) magmas. Felsic magmas are thought to form by addition of heat or water vapor to rock of

1302-415: A result, they contain micas such as biotite and muscovite instead of hornblende. Their strontium isotope ratio is typically greater than 0.708, suggesting a crustal origin. They also commonly contain xenoliths of metamorphosed sedimentary rock, and host tin ores. Their magmas are water-rich, and they readily solidify as the water outgasses from the magma at lower pressure, so they less commonly make it to

1395-598: A wide area, hiring several auditoria for worship. The western part of Enfield is largely residential, with shopping centres in Southgate , Palmers Green and Cockfosters . Parts of Enfield experienced rioting in August 2011 , in which a private car and a van were set alight and completely destroyed, a police car vandalised (smashed windows) and a number of shops in Enfield Town Centre as well as others in

1488-466: Is grus , which is often made up of coarse-grained fragments of disintegrated granite. Climatic variations also influence the weathering rate of granites. For about two thousand years, the relief engravings on Cleopatra's Needle obelisk had survived the arid conditions of its origin before its transfer to London. Within two hundred years, the red granite has drastically deteriorated in the damp and polluted air there. Soil development on granite reflects

1581-545: Is microgranite . The extrusive igneous rock equivalent of granite is rhyolite . Granitic rock is widely distributed throughout the continental crust . Much of it was intruded during the Precambrian age; it is the most abundant basement rock that underlies the relatively thin sedimentary veneer of the continents. Outcrops of granite tend to form tors , domes or bornhardts , and rounded massifs . Granites sometimes occur in circular depressions surrounded by

1674-476: Is 'open land of a man called Ēana', or 'where lambs are reared', from the Old English feld with an Old English personal name or with Old English ēan 'lamb'. The feld would have been a reference to an area cleared of trees within woodland that would later become known as Enfield Chase . In Roman times , Enfield was connected to Londinium by Ermine Street , the great Roman road which stretched all

1767-517: Is 3–6·10 Pa·s. The melting temperature of dry granite at ambient pressure is 1215–1260 °C (2219–2300 °F); it is strongly reduced in the presence of water, down to 650 °C at a few hundred megapascals of pressure. Granite has poor primary permeability overall, but strong secondary permeability through cracks and fractures if they are present. A worldwide average of the chemical composition of granite, by weight percent, based on 2485 analyses: The medium-grained equivalent of granite

1860-613: Is Enfield's largest school, and The College of Haringey, Enfield and North East London also has a campus in the borough. In 2007 a new school named Oasis Academy Enfield was opened, following the takeover of Albany by the Oasis Company as Oasis Academy Hadley . The Latymer School is another Grammar school in the borough, and is based in the Edmonton area. Enfield County School is an all girls comprehensive school which sits opposite Enfield Grammar Boys school in Enfield town. It

1953-499: Is a London borough in Greater London, England. The main communities in the borough are Edmonton , Enfield , Southgate and Palmers Green . Enfield is an Outer London borough and forms part of North London , being the northernmost borough and bordering Hertfordshire to the north and Essex to the northeast. The local authority is Enfield London Borough Council , based at Enfield Civic Centre . The borough's population

SECTION 20

#1732791028557

2046-685: Is a split site school with the lower years situated towards the area of Forty Hall. Middlesex University , the former polytechnic, used to have two campuses in Enfield: Cat Hill and Trent Park . These sites both closed in 2011 and courses were relocated to the Hendon campus. Oak Hill Theological College , an associate college of Middlesex University, is located in the borough. Capel Manor College also offers various courses. The London Borough of Enfield has three fire stations; Edmonton, Enfield and Southgate. However, if an incident requires

2139-598: Is also played in the area with Futsal Club Enfield who were founded in 2007 playing in the National Futsal League Premiership South Division for 2019/20. Gaelic Football is also played in the area. The club North London Shamrocks play at Tottenhall Playing FIelds. Granite Granite is typical of a larger family of granitic rocks , or granitoids , that are composed mostly of coarse-grained quartz and feldspars in varying proportions. These rocks are classified by

2232-410: Is an excess of aluminum beyond what can be taken up in feldspars (Al 2 O 3 > CaO + K 2 O + Na 2 O) are described as peraluminous , and they contain aluminum-rich minerals such as muscovite . The average density of granite is between 2.65 and 2.75 g/cm (165 and 172 lb/cu ft), its compressive strength usually lies above 200 MPa (29,000 psi), and its viscosity near STP

2325-637: Is believed to have a mass of around 81 tonnes. It was the tallest temple in south India. Imperial Roman granite was quarried mainly in Egypt, and also in Turkey, and on the islands of Elba and Giglio . Granite became "an integral part of the Roman language of monumental architecture". The quarrying ceased around the third century AD. Beginning in Late Antiquity the granite was reused, which since at least

2418-656: Is bordered by Chingford to the east and Ponders End and Edmonton to the west, and covers 334 acres (135 hectares) with a perimeter of 3.5 miles (5.6 km). There is no public access. The reservoir was conceived as part of an overall plan for the Lea Valley and laid before the Royal Commission on Water Supply (Balfour Committee) in 1893. At the time the responsible authority was the East London Waterworks Company . However, under

2511-434: Is called a binary or two-mica granite. Two-mica granites are typically high in potassium and low in plagioclase, and are usually S-type granites or A-type granites, as described below . Another aspect of granite classification is the ratios of metals that potentially form feldspars. Most granites have a composition such that almost all their aluminum and alkali metals (sodium and potassium) are combined as feldspar. This

2604-673: Is estimated to be 333,794. It borders the London boroughs of Barnet to the west, Haringey to the south, and Waltham Forest to the southeast. To the north are the districts of Hertsmere , Welwyn Hatfield and Broxbourne (in Hertfordshire ), and to the east is Epping Forest District in Essex. Enfield was recorded in Domesday Book in 1086 as Enefelde , and as Einefeld in 1214, Enfeld in 1293, and Enfild in 1564: that

2697-466: Is home to the well-renowned Enfield Grammar School , founded in 1558, which still uses its Tudor building which is now often referred to as the Old Hall. Enfield Grammar School is based in the center of Enfield Town. St Ignatius' College is the borough's largest Catholic school and one of the best-performing non-selective schools in the borough, at both GCSE and A-Level . Bishop Stopford's School

2790-493: Is known in heraldry as an " Enfield " (or colloquially as the Enfield beast), and is used extensively as a logo representing Enfield, particularly by the borough council. The borough's Civic Centre is in Silver Street, Enfield Town , and is home to the council. Enfield Town is also home to the local credit union, North London Credit Union . In 2007, Enfield Town centre completed a major redevelopment project under

2883-433: Is limited by the amount of thermal energy available, which must be replenished by crystallization of higher-melting minerals in the magma. Thus, the magma is melting crustal rock at its roof while simultaneously crystallizing at its base. This results in steady contamination with crustal material as the magma rises. This may not be evident in the major and minor element chemistry, since the minerals most likely to crystallize at

William Girling Reservoir - Misplaced Pages Continue

2976-404: Is permeated by sheets and channels of light granitic rock (the leucosome ). The leucosome is interpreted as partial melt of a parent rock that has begun to separate from the remaining solid residue (the melanosome). If enough partial melt is produced, it will separate from the source rock, become more highly evolved through fractional crystallization during its ascent toward the surface, and become

3069-454: Is relieved when overlying material is removed by erosion or other processes. Chemical weathering of granite occurs when dilute carbonic acid , and other acids present in rain and soil waters, alter feldspar in a process called hydrolysis . As demonstrated in the following reaction, this causes potassium feldspar to form kaolinite , with potassium ions, bicarbonate, and silica in solution as byproducts. An end product of granite weathering

3162-419: Is responsible for local primary health care, taking over this role from Enfield Primary Care NHS Trust in 2013. Another hospital in the borough, Highlands , was closed in 1993. The London Borough of Enfield is the education authority for the district. Education is provided in a mix of community , voluntary aided and state schools . A number of private schools are also located in the borough. The borough

3255-411: Is some concern that some granite sold as countertops or building material may be hazardous to health. Dan Steck of St. Johns University has stated that approximately 5% of all granite is of concern, with the caveat that only a tiny percentage of the tens of thousands of granite slab types have been tested. Resources from national geological survey organizations are accessible online to assist in assessing

3348-479: Is that magma will rise through the crust as a single mass through buoyancy . As it rises, it heats the wall rocks , causing them to behave as a power-law fluid and thus flow around the intrusion allowing it to pass without major heat loss. This is entirely feasible in the warm, ductile lower crust where rocks are easily deformed, but runs into problems in the upper crust which is far colder and more brittle. Rocks there do not deform so easily: for magma to rise as

3441-410: Is the case when K 2 O + Na 2 O + CaO > Al 2 O 3 > K 2 O + Na 2 O. Such granites are described as normal or metaluminous . Granites in which there is not enough aluminum to combine with all the alkali oxides as feldspar (Al 2 O 3 < K 2 O + Na 2 O) are described as peralkaline , and they contain unusual sodium amphiboles such as riebeckite . Granites in which there

3534-459: Is typically orthoclase or microcline and is often perthitic . The plagioclase is typically sodium-rich oligoclase . Phenocrysts are usually alkali feldspar. Granitic rocks are classified according to the QAPF diagram for coarse grained plutonic rocks and are named according to the percentage of quartz , alkali feldspar ( orthoclase , sanidine , or microcline ) and plagioclase feldspar on

3627-428: Is uncommon, is classified simply as quartz-rich granitoid or, if composed almost entirely of quartz, as quartzolite . True granites are further classified by the percentage of their total feldspar that is alkali feldspar. Granites whose feldspar is 65% to 90% alkali feldspar are syenogranites , while the feldspar in monzogranite is 35% to 65% alkali feldspar. A granite containing both muscovite and biotite micas

3720-789: The London Assembly , the borough forms part of the Enfield and Haringey constituency. Religion in London Borough of Enfield (2021) Two major NHS hospitals, Chase Farm Hospital operated by the Royal Free London NHS Foundation Trust and North Middlesex Hospital operated by the North Middlesex University Hospital NHS Trust, are located in the borough. NHS Enfield Clinical Commissioning Group

3813-1113: The Queen Elizabeth II athletics stadium, the Enfield Ignatians Rugby Club and numerous football , rugby and baseball diamonds. The playing fields were used as a POW camp for Italians during World War II . The second largest playing fields are at Firs Farm on Firs Lane. There are a handful of rugby pitches along with more than a dozen football pitches. These are used by local amateur football clubs including Winchmore Hill Football Club , Mayfield Athletic FC and Southgate County FC. The pitches drain reasonably well but are generally in poor condition with old, rusted goalposts. The changing facilities are also very dilapidated, with some changing rooms being no more than concrete sheds with corrugated roofs. Many sports teams and clubs are located in Enfield; Winchmore Hill Sports Club , Winchmore Hill Football Club , Enfield Town F.C. , Enfield 1893 F.C. , Cockfosters F.C. , Enfield Borough F.C. and Futsal Club Enfield are

William Girling Reservoir - Misplaced Pages Continue

3906-536: The berm were constructed at a bank slope of 1 in 8. It was considered necessary to reinforce the NW corner (Ponders End) with sheet-piling which was driven, suspended from a Weldex crane (see photo) ending in 2020 Water is pumped from the River Lee Diversion through five inlet pumps with a maximum of 600 ML/d, though normal operation is 250 ML/d. In addition there are two 200 mm diameter inlets from

3999-571: The A-Q-P half of the diagram. True granite (according to modern petrologic convention) contains between 20% and 60% quartz by volume, with 35% to 90% of the total feldspar consisting of alkali feldspar . Granitic rocks poorer in quartz are classified as syenites or monzonites , while granitic rocks dominated by plagioclase are classified as granodiorites or tonalites . Granitic rocks with over 90% alkali feldspar are classified as alkali feldspar granites . Granitic rock with more than 60% quartz, which

4092-618: The Enfield Retail Park being broken into and looted. The Sony Distribution Centre in the Innova Business Park, near Waltham Cross, was burnt to the ground. In September 2012, a year after the attack, a rebuilt Sony Distribution Centre was opened by the prime minister, David Cameron. The local authority is Enfield Council, based at the Civic Centre on Silver Street in Enfield. Since 2000, for elections to

4185-543: The Enfield Town Market Place and St. Andrew's Church, the school having been extended several times since 1586. A new hall and further additions were completed shortly before World War II. Nearby historically was the palace of Edward VI , where Elizabeth I lived while a princess, including during the final illness of Henry VIII . Edward was taken there to join her, so that in the company of his sister, Edward Seymour, 1st Earl of Hertford could break

4278-615: The European Union safety standards (section 4.1.1.1 of the National Health and Engineering study) and radon emission levels well below the average outdoor radon concentrations in the US. Granite and related marble industries are considered one of the oldest industries in the world, existing as far back as Ancient Egypt . Major modern exporters of granite include China, India, Italy, Brazil, Canada, Germany, Sweden, Spain and

4371-758: The Great , in order to keep the Danes to the east of the River Lea . After the Norman Conquest , both Enfield and Edmonton were mentioned in Domesday Book . Both had churches, and Enfield had 400 inhabitants, Edmonton 300. Enfield is also described as having a "parc". This parc—a heavily forested area for hunting—was key to Enfield's existence in the Middle Ages (see Enfield Old Park ). Wealthy Londoners came to Enfield first to hunt, and then to build houses in

4464-811: The Middlesex Cricket League or the Hertfordshire League. Enfield, Southgate, and Winchmore Hill have long been the area's most successful cricket clubs, regularly competing in the Middlesex Premier League. Enfield (in 1988) and Southgate (in 1977) are both past winners of the ECB National Club Cricket Championship The main swimming club in the borough is Enfield Swim Squad, which was created from an amalgamation of Edmonton Phoenix S.C. and Griffins S.C. of Enfield. Futsal

4557-639: The Mohs hardness scale) , and tough. These properties have made granite a widespread construction stone throughout human history. The word "granite" comes from the Latin granum , a grain, in reference to the coarse-grained structure of such a completely crystalline rock. Granitic rocks mainly consist of feldspar , quartz , mica , and amphibole minerals , which form an interlocking, somewhat equigranular matrix of feldspar and quartz with scattered darker biotite mica and amphibole (often hornblende ) peppering

4650-589: The North London Artificial Recharge borehole scheme. The outlet tower consists of a granite faced dry shaft that houses a 54 inches (140 cm) diameter vertical pipe, with draw-off pipes at four different levels. The lower end of the standpipe is connected to a 50 inches (130 cm) diameter steel outlet conduit . The water is conveyed to the Coppermills Water Treatment Works for treatment, with

4743-511: The United States. The Red Pyramid of Egypt ( c.  2590 BC ), named for the light crimson hue of its exposed limestone surfaces, is the third largest of Egyptian pyramids . Pyramid of Menkaure , likely dating 2510 BC, was constructed of limestone and granite blocks. The Great Pyramid of Giza (c. 2580 BC ) contains a huge granite sarcophagus fashioned of "Red Aswan Granite". The mostly ruined Black Pyramid dating from

SECTION 50

#1732791028557

4836-419: The base of the chamber are the same ones that would crystallize anyway, but crustal assimilation is detectable in isotope ratios. Heat loss to the country rock means that ascent by assimilation is limited to distance similar to the height of the magma chamber. Physical weathering occurs on a large scale in the form of exfoliation joints , which are the result of granite's expanding and fracturing as pressure

4929-418: The big difference in rheology between mafic and felsic magmas makes this process problematic in nature. Granitization is an old, and largely discounted, hypothesis that granite is formed in place through extreme metasomatism . The idea behind granitization was that fluids would supposedly bring in elements such as potassium, and remove others, such as calcium, to transform a metamorphic rock into granite. This

5022-584: The birth of modern soil mechanics in Britain . The reservoir was redesigned to increase its capacity by 11.3%. Construction was further delayed by the outbreak of the Second World War and the reservoir was not finally completed until 1951, when it was officially opened on 4 September by William Girling, Chairman of the MWB, and named eponymously. As part of the 2012 Summer Olympics security exercise,

5115-1105: The borough, participating in various ceremonies and events throughout the year, including the Enfield Town Show, St Georges Day Parade and on Remembrance Day Parade. The Air Training Corps has three units in the area, No.85 (Enfield & Southgate) Squadron based in Winchmore Hill and Enfield Town, No.1159 (Edmonton) Squadron based in Edmonton, No.1571 (Ayleward) Squadron based in Aylward School and No.2473 (Highlands & Southgate) Squadron in Highlands School, Southgate. The Red Room music and film project ran from 2008 – 2014 based in Ponders End, aimed at 13 – 19 year olds supported and funded by Enfield Council. Enfield Dispatch and Enfield Independent provide local news. Enfield's King George's Field , named in memory of King George V , includes

5208-460: The core forming a filter. The core is a maximum of 12 feet (3.7 m) wide at the base and tapers to 5 feet (1.5 m) wide at the crest. The core typically extends 3 feet (91 cm) into the London Clay to form a watertight cut off. The embankment shoulders consist of zones of ballast and filling material. The upper embankments slopes are 1 in 2.5 externally, whilst the lower slopes to

5301-457: The dam failed before any water had been stored. Investigations were under way when a second slip occurred in December 1937. Two independent soil mechanics experts, Dr. Herbert Chatley and Professor Karl Terzaghi , were called in and both made recommendations. In July 1938 the MWB made important modifications to the original design. Subsequent investigations into this landslip can be regarded as

5394-404: The division between S-type (produced by underplating) and I-type (produced by injection and differentiation) granites, discussed below. The composition and origin of any magma that differentiates into granite leave certain petrological evidence as to what the granite's parental rock was. The final texture and composition of a granite are generally distinctive as to its parental rock. For instance,

5487-473: The early 16th century became known as spolia . Through the process of case-hardening , granite becomes harder with age. The technology required to make tempered metal chisels was largely forgotten during the Middle Ages. As a result, Medieval stoneworkers were forced to use saws or emery to shorten ancient columns or hack them into discs. Giorgio Vasari noted in the 16th century that granite in quarries

5580-627: The facility for bulk transfer to Essex and Suffolk Water . The water is part of the Chingford Reservoirs Site of Special Scientific Interest (SSSI). It is a major wintering ground for wildfowl and wetland birds, including nationally important numbers of some species. The water also forms a moult refuge for a large population of wildfowl during the late summer months. A total of 85 wetland species have been recorded here in recent years. London Borough of Enfield The London Borough of Enfield ( pronunciation )

5673-579: The first magma to enter solidifies and provides a form of insulation for later magma. These mechanisms can operate in tandem. For example, diapirs may continue to rise through the brittle upper crust through stoping , where the granite cracks the roof rocks, removing blocks of the overlying crust which then sink to the bottom of the diapir while the magma rises to take their place. This can occur as piecemeal stopping (stoping of small blocks of chamber roof), as cauldron subsidence (collapse of large blocks of chamber roof), or as roof foundering (complete collapse of

SECTION 60

#1732791028557

5766-745: The garden exhibitions at Capel Manor , Myddleton House (part of the Lee Valley Park ) and the Whitewebbs Museum of Transport. The Borough's own museum is based in Thomas Hardy House, 39 London Road. Scouting and Guiding have many groups within Enfield. The annual St George's Day Parade has around a thousand young people marching through Enfield Town, led by the Enfield District Scout Band. The Boys' and Girls' Brigade are also quite active within

5859-469: The green, wooded surroundings. In 1303, Edward I of England granted Enfield a charter to hold a weekly market , which has continued up to this day. The old market cross was removed in the early 20th century to make way for a monument to the coronation of King Edward VII , but was preserved by the horticulturalist E. A. Bowles for his garden at nearby Myddelton House, where it remains today. Enfield Grammar School with its Tudor Old Hall stands next to

5952-713: The grotto is a highly regarded piece of Buddhist art , and along with the temple complex to which it belongs, Seokguram was added to the UNESCO World Heritage List in 1995. Rajaraja Chola I of the Chola Dynasty in South India built the world's first temple entirely of granite in the 11th century AD in Tanjore , India . The Brihadeeswarar Temple dedicated to Lord Shiva was built in 1010. The massive Gopuram (ornate, upper section of shrine)

6045-570: The lighter color minerals. Occasionally some individual crystals ( phenocrysts ) are larger than the groundmass , in which case the texture is known as porphyritic . A granitic rock with a porphyritic texture is known as a granite porphyry . Granitoid is a general, descriptive field term for lighter-colored, coarse-grained igneous rocks. Petrographic examination is required for identification of specific types of granitoids. Granites can be predominantly white, pink, or gray in color, depending on their mineralogy . The alkali feldspar in granites

6138-474: The lower crust , rather than by decompression of mantle rock, as is the case with basaltic magmas. It has also been suggested that some granites found at convergent boundaries between tectonic plates , where oceanic crust subducts below continental crust, were formed from sediments subducted with the oceanic plate. The melted sediments would have produced magma intermediate in its silica content, which became further enriched in silica as it rose through

6231-729: The lower continental crust at high thermal gradients. This leads to significant extraction of hydrous felsic melts from granulite-facies resitites. A-type granites occur in the Koettlitz Glacier Alkaline Province in the Royal Society Range, Antarctica. The rhyolites of the Yellowstone Caldera are examples of volcanic equivalents of A-type granite. M-type granite was later proposed to cover those granites that were clearly sourced from crystallized mafic magmas, generally sourced from

6324-435: The magma is inevitable once enough magma has accumulated. However, the question of precisely how such large quantities of magma are able to shove aside country rock to make room for themselves (the room problem ) is still a matter of research. Two main mechanisms are thought to be important: Of these two mechanisms, Stokes diapirism has been favoured for many years in the absence of a reasonable alternative. The basic idea

6417-426: The magma. Other processes must produce these great volumes of felsic magma. One such process is injection of basaltic magma into the lower crust, followed by differentiation, which leaves any cumulates in the mantle. Another is heating of the lower crust by underplating basaltic magma, which produces felsic magma directly from crustal rock. The two processes produce different kinds of granites, which may be reflected in

6510-408: The magmatic parent of granitic rock. The residue of the source rock becomes a granulite . The partial melting of solid rocks requires high temperatures and the addition of water or other volatiles which lower the solidus temperature (temperature at which partial melting commences) of these rocks. It was long debated whether crustal thickening in orogens (mountain belts along convergent boundaries )

6603-405: The mantle. Although the fractional crystallisation of basaltic melts can yield small amounts of granites, which are sometimes found in island arcs, such granites must occur together with large amounts of basaltic rocks. H-type granites were suggested for hybrid granites, which were hypothesized to form by mixing between mafic and felsic from different sources, such as M-type and S-type. However,

6696-412: The most prominent. The once successful football club, Enfield FC, were forced into a nomadic existence after the sale of their Southbury Road ground and became defunct at the end of the 2006/2007 season after years of ground sharing at many Hertfordshire based clubs. Enfield 1893 were formed after Enfield FC's demise and have spent time groundsharing at Ware FC and Broxbourne Borough FC. They finally found

6789-518: The name PalaceXchange while retaining the Palace Gardens Shopping Centre. An extension was added to the existing retail area with many new shops, and a second multi-storey car park was built along with a new road layout. A major redevelopment of Edmonton Green including the shopping centre, and adjacent municipal housing over a wide area, started in 1999. This is still on-going, and provides new housing, health facilities,

6882-407: The news to Edward, formally announcing the death of their royal father in the presence chamber at Enfield, on his knees to make formal obeisance to the boy as King. Later Elizabeth held court there when she was queen (this was remembered in the name Palace Gardens that was a street running behind Pearsons department store and is still recalled in the name of Enfield's shopping centre). Enfield has

6975-441: The overlying crust. Early fractional crystallisation serves to reduce a melt in magnesium and chromium, and enrich the melt in iron, sodium, potassium, aluminum, and silicon. Further fractionation reduces the content of iron, calcium, and titanium. This is reflected in the high content of alkali feldspar and quartz in granite. The presence of granitic rock in island arcs shows that fractional crystallization alone can convert

7068-492: The provision of infrastructure. The Edmonton district was divided in 1881, when its western part was made a separate district called Southgate. Such districts were reconstituted as urban districts under the Local Government Act 1894 . Each of the three urban districts was later raised to the status of a municipal borough : Southgate in 1933, Edmonton in 1937, and Enfield in 1955. The modern borough

7161-643: The provisions of the Metropolis Water Act 1902 , the undertakings of this and seven other companies were transferred to the Metropolitan Water Board (MWB). Work began in 1936 when the tender of John Mowlem (for £682,156) was accepted. The project was led by civil engineer , Robert Wynne-Edwards . Due to the use of mechanical scrapers and bulldozers , which were being used for the first time in British dam construction, progress

7254-736: The reign of Amenemhat III once had a polished granite pyramidion or capstone, which is now on display in the main hall of the Egyptian Museum in Cairo (see Dahshur ). Other uses in Ancient Egypt include columns , door lintels , sills , jambs , and wall and floor veneer. How the Egyptians worked the solid granite is still a matter of debate. Tool marks described by the Egyptologist Anna Serotta indicate

7347-420: The relative percentages of quartz, alkali feldspar, and plagioclase (the QAPF classification ), with true granite representing granitic rocks rich in quartz and alkali feldspar. Most granitic rocks also contain mica or amphibole minerals, though a few (known as leucogranites ) contain almost no dark minerals. Granite is nearly always massive (lacking any internal structures), hard (falling between 6 and 7 on

7440-464: The reservoir was identified as suitable for the deployment of Rapier surface-to-air missiles . The geology of the site is alluvium underlain by river terrace gravels and in turn overlying the London Clay formation. The reservoir is formed by a continuous earthen embankment that encloses the basin. The embankments consist of a central puddle clay core with a selected material adjacent to

7533-564: The risk factors in granite country and design rules relating, in particular, to preventing accumulation of radon gas in enclosed basements and dwellings. A study of granite countertops was done (initiated and paid for by the Marble Institute of America) in November 2008 by National Health and Engineering Inc. of USA. In this test, all of the 39 full-size granite slabs that were measured for the study showed radiation levels well below

7626-418: The rock's high quartz content and dearth of available bases, with the base-poor status predisposing the soil to acidification and podzolization in cool humid climates as the weather-resistant quartz yields much sand. Feldspars also weather slowly in cool climes, allowing sand to dominate the fine-earth fraction. In warm humid regions, the weathering of feldspar as described above is accelerated so as to allow

7719-414: The rocks often bear a close resemblance. Under these conditions, granitic melts can be produced in place through the partial melting of metamorphic rocks by extracting melt-mobile elements such as potassium and silicon into the melts but leaving others such as calcium and iron in granulite residues. This may be the origin of migmatites . A migmatite consists of dark, refractory rock (the melanosome ) that

7812-492: The roof of a shallow magma chamber accompanied by a caldera eruption.) There is evidence for cauldron subsidence at the Mt. Ascutney intrusion in eastern Vermont. Evidence for piecemeal stoping is found in intrusions that are rimmed with igneous breccia containing fragments of country rock. Assimilation is another mechanism of ascent, where the granite melts its way up into the crust and removes overlying material in this way. This

7905-435: The surface than magmas of I-type granites, which are thus more common as volcanic rock (rhyolite). They are also orogenic but range from metaluminous to strongly peraluminous. Although both I- and S-type granites are orogenic, I-type granites are more common close to the convergent boundary than S-type. This is attributed to thicker crust further from the boundary, which results in more crustal melting. A-type granites show

7998-502: The uranium washes into the sediments from the granite uplands and associated, often highly radioactive pegmatites. Cellars and basements built into soils over granite can become a trap for radon gas, which is formed by the decay of uranium. Radon gas poses significant health concerns and is the number two cause of lung cancer in the US behind smoking. Thorium occurs in all granites. Conway granite has been noted for its relatively high thorium concentration of 56±6 ppm. There

8091-617: The use of flint tools on finer work with harder stones, e.g. when producing the hieroglyphic inscriptions. Patrick Hunt has postulated that the Egyptians used emery , which has greater hardness. The Seokguram Grotto in Korea is a Buddhist shrine and part of the Bulguksa temple complex. Completed in 774 AD, it is an artificial grotto constructed entirely of granite. The main Buddha of

8184-455: The way up to York . Artefacts found in the early 1900s reveal that there were Roman settlements in the areas that are now Edmonton and Bush Hill Park. In 790 King Offa of Mercia was recorded as giving the lands of Edmonton to St Albans Abbey . The area became strategically important as East Anglia was taken over by the Danes . In the 890s strongholds were built by men loyal to King Alfred

8277-492: Was created in 1965 under the London Government Act 1963 , covering the combined area of the former boroughs of Enfield, Edmonton and Southgate, which were all abolished at the same time. The area was transferred from Middlesex to Greater London to become one of the 32 London Boroughs. The armorial bearings of these three boroughs were also merged. The heraldic beast on the shield of the Enfield coat of arms

8370-629: Was manufactured in Hotpoint 's now closed Enfield plant. The Barclays Bank branch in Enfield was the first place in the world to have an ATM or cash machine; it was officially opened in June 1967 by Reg Varney , a television actor and personality most famous for his lead role in the comedy series On the Buses . This historical event was marked by a silver plaque on the wall of the bank, and later by an English Heritage Blue plaque . A fine example of

8463-500: Was rapid. The design, by Sir Jonathan Roberts Davidson , President of the Institution of Civil Engineers 1948/49 , attracted widespread technical interest in 1937 when a major slip occurred in the partly formed embankment at the north-west corner. When the embankment fill had reached 23 feet (7.0 m) a 66-foot (20 m) width had dropped 2 feet 4 inches (71 cm) and moved forward 13 feet (4.0 m). Fortunately,

8556-405: Was sufficient to produce granite melts by radiogenic heating , but recent work suggests that this is not a viable mechanism. In-situ granitization requires heating by the asthenospheric mantle or by underplating with mantle-derived magmas. Granite magmas have a density of 2.4 Mg/m , much less than the 2.8 Mg/m of high-grade metamorphic rock. This gives them tremendous buoyancy, so that ascent of

8649-564: Was supposed to occur across a migrating front. However, experimental work had established by the 1960s that granites were of igneous origin. The mineralogical and chemical features of granite can be explained only by crystal-liquid phase relations, showing that there must have been at least enough melting to mobilize the magma. However, at sufficiently deep crustal levels, the distinction between metamorphism and crustal melting itself becomes vague. Conditions for crystallization of liquid magma are close enough to those of high-grade metamorphism that

#556443