South Western Ambulance Service
The South Western Ambulance Service NHS Foundation Trust is the organisation responsible for providing ambulance services for the National Health Service across South West England. On March 1, 2011 SWASFT was the first ambulance service in the country to become a Foundation Trust; the Trust acquired neighbouring Great Western Ambulance Service on 1 February 2013. SWASFT serves a population of more than 5.47 million, its area is estimated to receive an influx of over 17.5 million visitors each year. The operational area is predominantly rural but has large urban centres including Bristol, Exeter, Bath, Gloucester and Poole; the headquarters for the service is in Exeter and the service has 96 ambulance stations and 6 air bases. The Chief Executive is Ken Wenman, appointed on 1 July 2006 on creation of the trust, having served as the Chief Executive of the former Dorset Ambulance Service NHS Trust; the Trust’s core operations include: Emergency ambulance 999 services Urgent Care Services – GP out-of-hours medical care NHS 111 call-handling and triage services Tiverton Urgent Care Centre.
It is one of ten Ambulance Trusts providing England with emergency medical services and employs more than 4,500 clinical and operational staff. In addition there are around 3,200 volunteers including community first responders, BASICS doctors, fire co-responders and patient transport drivers; the Trust is one of the largest in England. It covers 827 miles of coastline. In 2015/16 one in eight 999 calls to South Western Ambulance Service were treated over the telephone. "Hear and treat", where the patient receives clinical advice over the telephone, accounted for 12.7% of calls. For 36.4% of incidents the patients experienced "see and treat", when the patient receives treatment or advice at the scene of the incident. In a further 7.7% of incidents, the patient was taken to a non-emergency hospital department such as a community hospital or minor injuries unit. The remaining incidents resulted in a patient being taken to a hospital emergency department, thus the majority of incidents resulted in a patient not being conveyed.
SWASFT is the best performing ambulance service in the country for non-conveyance rates. In addition 62% of patients taken to hospital are admitted – this is again the highest performance for an ambulance trust in the country; this means that when SWASFT takes a patient to an emergency department they are to be admitted, not treated and discharged, therefore confirming, the right place for them to receive the care they need. There are 96 ambulance stations, six air ambulance bases, three clinical control rooms, two Hazardous Area Response Team bases and one boat across the South Western Ambulance Service operational area. In 2016 the Care Quality Commission told the South Western Ambulance Service to make significant improvements in the NHS 111 service; the inspection of the trust in 2016 identified several areas. In 2018 the trust said it would need an extra £12 million a year to meet the new ambulance performance standards; the number of compliments received by the Trust in 2014/15 increased by 41% to 2,055 while complaints rose by 20% to 1,268.
The Trust is split into three divisions: West Division: covering Devon and Cornwall, including its Headquarters at Exeter East Division: covering Somerset and Dorset North Division: consisting of the footprint of the former Great Western Ambulance Service as well as the Burnham-on-sea and Shepton Mallet stationsThe Trust has 96 ambulance stations among the counties that it serves: Cornwall Devon Dorset Somerset Avon Wiltshire Gloucestershire 306 - 999 Emergency Ambulances 57 Patient Transport Ambulances 234 Rapid Response Vehicles 7 Rapid Response Motorcycles 5 Bicycles 2 Hazardous Area Response Teams 1 Boat – ALN 043'Star of Life’ Wave Saver 1000 Class Ambulance Boat SWASFT provides the non-emergency 111 helpline and triage service for Dorset. In May 2014 the Trust won a contract to run a doctor-led minor injuries unit at Tiverton and District Hospital, open seven days a week. Patients do not need an appointment to visit the centre, which provides treatment for minor injuries and ailments including: Cuts and wounds.
The River Severn is the longest river in Great Britain at a length of 220 miles, the second longest in the British Isles after the River Shannon in Ireland. It rises at an altitude of 2,001 feet on Plynlimon, close to the Ceredigion/Powys border near Llanidloes, in the Cambrian Mountains of mid Wales, it flows through Shropshire and Gloucestershire, with the county towns of Shrewsbury and Gloucester on its banks. With an average discharge of 107 m3/s at Apperley, the Severn is by far the greatest river in terms of water flow in England and Wales; the river is considered to become the Severn Estuary after the Second Severn Crossing between Severn Beach, South Gloucestershire and Sudbrook, Monmouthshire. The river discharges into the Bristol Channel which in turn discharges into the Celtic Sea and the wider Atlantic Ocean; the Severn's drainage basin area is 4,409 square miles, excluding the River Wye and Bristol Avon which flow into the Severn Estuary. The major tributaries to the Severn are the Vyrnwy, Teme and Stour.
The name Severn is thought to derive from a Celtic original name *sabrinnā, of uncertain meaning. That name developed in different languages to become Sabrina to the Romans, Hafren in Welsh, Severn in English. A folk etymology developed, deriving the name from a mythical story of a nymph, who drowned in the river. Sabrina is the goddess of the River Severn in Celtic mythology; the story of Sabrina is featured in Milton's 1634 masque Comus. There is a statue of Sabrina in the Dingle Gardens at the Quarry, Shrewsbury, as well as a metal sculpture erected in 2013 in the town; as the Severn becomes tidal the associated deity changed to Nodens, represented mounted on a seahorse, riding on the crest of the Severn bore. The River Stour rises in the north of Worcestershire in the Clent Hills, near St Kenelm's Church at Romsley, it flows north into the adjacent West Midlands at Halesowen. It flows westwards through Cradley Heath and Stourbridge where it leaves the Black Country, it is joined by the Smestow Brook at Prestwood before it winds around southwards to Kinver, flows back into Worcestershire.
It passes through Wolverley and Wilden to its confluence with the Severn at Stourport-on-Severn. The River Vyrnwy, which begins at Lake Vyrnwy, flows eastwards through Powys before forming part of the border between England and Wales, joining the Severn near Melverley, Shropshire; the Rea Brook joins the Severn at Shrewsbury. The River Tern, after flowing south from Market Drayton and being joined by the River Meese and the River Roden, meets the Severn at Attingham Park; the River Worfe joins the Severn, just above Bridgnorth. The River Stour rising on the Clent Hills and flowing through Halesowen and Kidderminster, joins the Severn at Stourport. On the opposite bank, the tributaries are only brooks, Borle Brook, Dowles Brook draining the Wyre Forest, Dick Brook and Shrawley Brook; the River Teme flows eastwards from its source in Mid Wales, straddling the border between Shropshire and Herefordshire, it is joined by the River Onny, River Corve and River Rea before it joins the Severn downstream of Worcester.
Shit Brook near Much Wenlock was culverted to flow into the Severn. One of the several rivers named Avon, in this case the Warwickshire Avon, flows west through Rugby and Stratford-upon-Avon, it is joined by its tributary the River Arrow, before joining the Severn at Tewkesbury, Gloucestershire. The port of Bristol is on the Severn Estuary, where another River Avon flows into it through the Avon Gorge; the River Wye, from its source in Plynlimon in Wales, flows south east through the Welsh towns of Rhayader and Builth Wells. It enters Herefordshire, flows through Hereford, is shortly afterwards joined by the River Lugg, before flowing through Ross-on-Wye and Monmouth, southwards where it forms part of the boundary between England and Wales, it flows into the Severn near the town of Chepstow upstream of the Bristol Avon on the opposite bank. The River Usk flows into the Severn Estuary just south of Newport; the Rad Brook is a small river in England. It enters the River Severn there. Below is a list of major towns and cities that the Severn flows through: Through Powys: Llanidloes Newtown WelshpoolThrough Shropshire: Shrewsbury Ironbridge BridgnorthThrough Worcestershire: Bewdley Stourport-on-Severn Worcester Upton-upon-SevernThrough Gloucestershire: Tewkesbury Gloucester The Severn is bridged at many places, many of these bridges are notable in their own right, with several designed and built by the engineer Thomas Telford.
There is the famous Iron Bridge at Ironbridge, the world's first iron arch bridge. The two major road bridges of the Severn crossing link south eastern Wales with the southern counties of England. Severn Bridge — opened in 1966 carrying what is now the M48 Second Severn Crossing — opened in 1996 carrying the M4 motorwayPrior to the construction of the first bridge in 1966, the channel was crossed by the Aust Ferry. Other notable bridges include: Buttington Bridge — built in 1872 Montford Bridge — Thomas Telford's first bridge design, built between 1790 and 1792 Welsh Bridge — in the centre of Shrewsbury, built in 1795 at a cost of £8,000 English Bridge — in Shrewsbury and completed in 1774 by John Gwynn Atcham Bridges — the old one built in 1774, while the newer one in 1929 carries th
Flora and fauna of Cornwall
Cornwall is the county that forms the tip of the southwestern peninsula of England. The mild climate allows rich plant cover, such as palm trees in the far south and west of the county and in the Isles of Scilly, due to sub-tropical conditions in the summer. On Cornwall's moors and high ground areas the high elevation makes tree cover impossible because of the wind, so these areas are populated by shrubs and bushes such as gorse and heather. Ferns, liverworts and fungi can all be found in the county. In the wettest areas of Bodmin Moor, sphagnum or bog moss can be found. Cornwall is home to many rare flower species at the southern end of the Lizard, due to its unique soil and geology. On the Lizard Peninsula, Cornish heath – the floral emblem of Cornwall – mesembryanthemums, butcher's broom, early meadow grass and a wide range of clovers including the Lizard clover and yellow wallpepper can be found; the north coast of Cornwall features maritime grassland and stunted woodland. The county's coastal waters are home to large populations of seals.
Porpoises and sharks are not uncommonly seen. St Ives made newspaper headlines after a reported sighting of a great white shark. Porbeagles inhabit the coastal waters but the etymology of the word is obscure. A common suggestion is that it combines "porpoise" and "beagle", referencing this shark's shape and tenacious hunting habits. Another is that it is derived from the Cornish porth, meaning "harbour", bugel, meaning "shepherd"; the Oxford English Dictionary states that the word was either borrowed from Cornish or formed from a Cornish first element with the English "beagle". Squalus cornubicus. Swanpool is the only location in the British Isles; the sea cliffs host many marine bird species with the Cornish chough returning to the county after a long absence. This rare bird holds the honour of appearing on the Cornish coat of arms and being the county animal of Cornwall; the tidal estuaries along the coasts contain large numbers of wading birds, while marshland bird species settle in the bogs and mires inland.
Bodmin Moor is a breeding ground for species such as lapwing and curlew. On and around the rivers, sand martins and kingfishers are seen, while after a decline in the 1960s and 1970s, otters have been returning in large numbers; the Camel Valley is one of the habitats for otters. Bude Canal offers an ideal habitat for water voles, although the population is declining because of habitat degradation and pollution, like in other parts of the country. Cornish chough: Pyrrhocorax pyrrhocorax pyrrhocorax, the nominate subspecies and smallest form, is endemic to the British Isles, where it is restricted to Ireland, the Isle of Man, the far west of Wales and Scotland, although it has recolonised Cornwall after an absence of many years. Mousehole Wild Bird Hospital and Sanctuary is a wildlife hospital based near Mousehole; the hospital was founded in 1928 by Dorothy and Phyllis Yglesias and became famous following the Torrey Canyon disaster. Cornish Seal Sanctuary, Gweek The Tamar Valley Area of Outstanding Natural Beauty covers around 195 km2 around the lower Tamar and its tributaries the Tavy and the Lynher.
It was first proposed in 1963, but was not designated until 1995. The Tamar Otter and Wildlife Centre has European and Asian short-clawed otters and a medium-sized duck pond, a nature trail including snowy and barn owls and other birds along it, it has a restaurant area and a gift shop. The nature trail is full of wildlife such as fallow and muntjac deer and the not quite so English wallabies; as well as this the nature trail has a waterfall falling down from the top of an old quarry and every few years different segments of the woodlands are coppiced. Some of the wood from this scheme is piled up in random areas of the woodlands as it makes a perfect home for badgers and many creepy crawlies. Several nature sites exist on the Lizard Peninsula, it is home to one of England's rarest breeding birds – the Cornish chough. This species of crow, distinctive due to its red beak and legs, as well as the haunting "chee-aw" call, began breeding on Lizard in 2002; this followed a concerted effort by the Cornish Chough Project in conjunction with DEFRA and the RSPB.
The Lizard contains some of the most specialised flora of any area in Britain, including many Red Data Book plant species. Of particular note is the Cornish heath, Erica vagans, that occurs in abundance here, but, found nowhere else in Britain, it is one of the few places where the rare formicine ant, Formica exsecta, can be found. The Lizard district has a local organisation, the Lizard Field Club, whose members have studied the natural history of the area since 1953. At Polruan the gorse covered south facing cliffs between Polruan and Polperro provide habitats for the goldfinch and stonechat in particular. Viparian life includes the adder; the latter is numerous. Marine life includes the basking shark. In 1972 a large example was seen at the end of Polruan Quay. Other fish that may be found in local waters including the estuary include: bass, seahorse, pipe fish, coalfish, plaice, conger eel, Eu
Scotland is a country, part of the United Kingdom. Sharing a border with England to the southeast, Scotland is otherwise surrounded by the Atlantic Ocean to the north and west, by the North Sea to the northeast and by the Irish Sea to the south. In addition to the mainland, situated on the northern third of the island of Great Britain, Scotland has over 790 islands, including the Northern Isles and the Hebrides; the Kingdom of Scotland emerged as an independent sovereign state in the Early Middle Ages and continued to exist until 1707. By inheritance in 1603, James VI, King of Scots, became King of England and King of Ireland, thus forming a personal union of the three kingdoms. Scotland subsequently entered into a political union with the Kingdom of England on 1 May 1707 to create the new Kingdom of Great Britain; the union created a new Parliament of Great Britain, which succeeded both the Parliament of Scotland and the Parliament of England. In 1801, the Kingdom of Great Britain and Kingdom of Ireland enacted a political union to create a United Kingdom.
The majority of Ireland subsequently seceded from the UK in 1922. Within Scotland, the monarchy of the United Kingdom has continued to use a variety of styles and other royal symbols of statehood specific to the pre-union Kingdom of Scotland; the legal system within Scotland has remained separate from those of England and Wales and Northern Ireland. The continued existence of legal, educational and other institutions distinct from those in the remainder of the UK have all contributed to the continuation of Scottish culture and national identity since the 1707 union with England; the Scottish Parliament, a unicameral legislature comprising 129 members, was established in 1999 and has authority over those areas of domestic policy which have been devolved by the United Kingdom Parliament. The head of the Scottish Government, the executive of the devolved legislature, is the First Minister of Scotland. Scotland is represented in the UK House of Commons by 59 MPs and in the European Parliament by 6 MEPs.
Scotland is a member of the British–Irish Council, sends five members of the Scottish Parliament to the British–Irish Parliamentary Assembly. Scotland is divided into councils. Glasgow City is the largest subdivision in Scotland in terms of population, with Highland being the largest in terms of area. "Scotland" comes from the Latin name for the Gaels. From the ninth century, the meaning of Scotia shifted to designate Gaelic Scotland and by the eleventh century the name was being used to refer to the core territory of the Kingdom of Alba in what is now east-central Scotland; the use of the words Scots and Scotland to encompass most of what is now Scotland became common in the Late Middle Ages, as the Kingdom of Alba expanded and came to encompass various peoples of diverse origins. Repeated glaciations, which covered the entire land mass of modern Scotland, destroyed any traces of human habitation that may have existed before the Mesolithic period, it is believed the first post-glacial groups of hunter-gatherers arrived in Scotland around 12,800 years ago, as the ice sheet retreated after the last glaciation.
At the time, Scotland was covered in forests, had more bog-land, the main form of transport was by water. These settlers began building the first known permanent houses on Scottish soil around 9,500 years ago, the first villages around 6,000 years ago; the well-preserved village of Skara Brae on the mainland of Orkney dates from this period. Neolithic habitation and ritual sites are common and well preserved in the Northern Isles and Western Isles, where a lack of trees led to most structures being built of local stone. Evidence of sophisticated pre-Christian belief systems is demonstrated by sites such as the Callanish Stones on Lewis and the Maes Howe on Orkney, which were built in the third millennium BCE; the first written reference to Scotland was in 320 BC by Greek sailor Pytheas, who called the northern tip of Britain "Orcas", the source of the name of the Orkney islands. During the first millennium BCE, the society changed to a chiefdom model, as consolidation of settlement led to the concentration of wealth and underground stores of surplus food.
The first Roman incursion into Scotland occurred in 79 AD. After the Roman victory, Roman forts were set along the Gask Ridge close to the Highland line, but by three years after the battle, the Roman armies had withdrawn to the Southern Uplands; the Romans erected Hadrian's Wall in northern England and the Limes Britannicus became the northern border of the Roman Empire. The Roman influence on the southern part of the country was considerable, they introduced Christianity to Scotland. Beginning in the sixth century, the area, now Scotland was divided into three areas: Pictland, a patchwork of small lordships in central Scotland; these societies were based on the family unit and had sharp divisions in wealth, although the vast majority were poor and worked full-time in subsistence agriculture. The Picts kept slaves through the ninth century. Gaelic influence over Pictland and Northumbria was facilitated by the large number of Gaelic-speaking clerics working as missionaries. Operating in the sixth ce
Longships Lighthouse is an active 19th century lighthouse about 1.25 mi off the coast of Land's End in Cornwall, England. It is the second lighthouse to be built on Carn Bras, the highest of the Longships islets which rises 39 feet above high water level. In 1988 the lighthouse was automated, the keepers withdrawn, it is now remotely monitored from the Trinity House Operations & Planning Centre in Harwich. The original tower was built in 1795 to the design of Trinity House architect Samuel Wyatt, it contained a fixed array of eighteen Argand lamps with reflectors, arranged in two tiers and shining out to sea. The lantern was 79 feet above sea level but high seas obscured its light. In 1869 Trinity House began constructing a replacement; the building of the present granite tower used much of the equipment, used in the construction of the Wolf Rock Lighthouse. It was equipped with a first-order fixed optic built by Dr John Hopkinson of Chance Brothers; the tower was first lit in December 1873 having cost £43,870 to build.
By 1884 it was showing an occulting light with red sectors warning ships away from the Brisons and Rundlestone. After these improvements, the S. S. Bluejacket was wrecked on rocks near the lighthouse on a clear night in 1898, nearly demolishing the lighthouse in the process. Due to bad weather there was a delay in relieving the men and supplying stores. In January 1901 there was some concern that the men had run short of provisions due to the severe weather, it was found that there was plenty of stores and the only hardship was their lack of tobacco. They had taken to smoking coffee and tea leaves instead. In 1967 the light was modernised: an electric bulb replaced the old paraffin burner and a new revolving optic was installed displaying an isophase light visible up to 19 nautical miles distant. At the same time the explosive fog signal was replaced with a more modern'supertyfon' fog horn, itself replaced by an electric emitter when the lighthouse was automated. In 1974 a helipad was constructed on top of the lantern easing access.
In 1988 the lighthouse was automated. The current lantern emits. Seaward flashes are white but they become red - due to tinted sectors - for any vessel straying too close to either Cape Cornwall to the north or Gwennap Head to the south-southeast; the white light has a range of 15 nautical miles, the red sector light a shorter range of 11 nautical miles. During poor visibility the fog horn sounds once every ten seconds. List of lighthouses in England Trinity House
South West England
South West England is one of nine official regions of England. It is the largest in area, covering 9,200 square miles, consists of the counties of Gloucestershire, Wiltshire, Dorset and Cornwall, as well as the Isles of Scilly. Five million people live in South West England; the region includes much of the ancient kingdom of Wessex. The largest city is Bristol. Other major urban centres include Plymouth, Gloucester, Exeter, Bath and the South East Dorset conurbation which includes Bournemouth and Christchurch. There are eight cities: Salisbury, Wells, Gloucester, Exeter and Truro, it includes two entire national parks and Exmoor. The northern part of Gloucestershire, near Chipping Campden, is as close to the Scottish border as it is to the tip of Cornwall; the region has by far the longest coastline of any English region. The region is at the first level of NUTS for Eurostat purposes. Key data and facts about the region are produced by the South West Observatory. Following the abolition of the South West Regional Assembly and Government Office, local government co-ordination across the region is now undertaken by South West Councils.
The region is known for its rich folklore, including the legend of King Arthur and Glastonbury Tor, as well as its traditions and customs. Cornwall has its own language and some regard it as a Celtic nation; the South West is known for Cheddar cheese. It is home to the Eden Project, Aardman Animations, the Glastonbury Festival, the Bristol International Balloon Fiesta, trip hop music and Cornwall's surfing beaches; the region has been home to some of Britain's most renowned writers, including Daphne du Maurier and Agatha Christie, both of whom set many of their works here, the South West is the location of Thomas Hardy's Wessex, the setting for many of his best-known novels. Most of the region is located on the South West Peninsula, between the English Channel and Bristol Channel, it has the longest coastline of all the English regions, totalling over 700 miles. Much of the coast is now protected from further substantial development because of its environmental importance, which contributes to the region's attractiveness to tourists and residents.
Geologically the region is divided into the igneous and metamorphic west and sedimentary east, the dividing line to the west of the River Exe. Cornwall and West Devon's landscape is of rocky coastline and high moorland, notably at Bodmin Moor and Dartmoor; these are due to the slate that underlie the area. The highest point of the region is High Willhays, at 2,038 feet, on Dartmoor. In North Devon the slates of the west and limestones of the east meet at Exmoor National Park; the variety of rocks of similar ages seen here have led to the county's name being lent to that of the Devonian period. The east of the region is characterised by limestone downland; the vales, with good irrigation, are home to the region's dairy agriculture. The Blackmore Vale was Thomas Hardy's "Vale of the Little Dairies"; the Southern England Chalk Formation extends into the region, creating a series of high, sparsely populated and archaeologically rich downs, most famously Salisbury Plain, but Cranborne Chase, the Dorset Downs and the Purbeck Hills.
These downs are the principal area of arable agriculture in the region. Limestone is found in the region, at the Cotswolds, Quantock Hills and Mendip Hills, where they support sheep farming. All of the principal rock types can be seen on the Jurassic Coast of Dorset and East Devon, where they document the entire Mesozoic era from west to east; the climate of South West England is classed as oceanic according to the Köppen climate classification. The oceanic climate experiences cool winters with warmer summers and precipitation all year round, with more experienced in winter. Annual rainfall is up to 2,000 millimetres on higher ground. Summer maxima averages range from 18 °C to 22 °C and winter minimum averages range from 1 °C to 4 °C across the south-west, it is the second windiest area of the United Kingdom, the majority of winds coming from the south-west and north-east. Government organisations predict the region to rise in temperature and become the hottest region in the United Kingdom. Inland areas of low altitude experience the least amount of precipitation.
They experience the highest summer maxima temperatures. Snowfalls are less so in comparison to higher ground, it experiences the lowest wind speeds and sunshine total in between that of the moors. The climate of inland areas is more noticeable the further north-east into the region. In comparison to inland areas, the coast experiences high minimum temperatures in winter, it experiences lower maximum temperatures during the summer. Rainfall is the lowest at the coast and snowfall is rarer than the rest of the region. Coastal areas are the windiest parts of the peninsula and they receive the most sunshine; the general coastal climate is more typical the further south-west into the region. Areas of moorland inland such as: Bodmin Moor and Exmoor experience lower temperatures and more precipitation than the rest of the south west (approxima
Granite is a common type of felsic intrusive igneous rock, granular and phaneritic in texture. Granites can be predominantly white, pink, or gray depending on their mineralogy; the word "granite" comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a holocrystalline rock. Speaking, granite is an igneous rock with between 20% and 60% quartz by volume, at least 35% of the total feldspar consisting of alkali feldspar, although the term "granite" is used to refer to a wider range of coarse-grained igneous rocks containing quartz and feldspar; the term "granitic" means granite-like and is applied to granite and a group of intrusive igneous rocks with similar textures and slight variations in composition and origin. These rocks consist of feldspar, quartz and amphibole minerals, which form an interlocking, somewhat equigranular matrix of feldspar and quartz with scattered darker biotite mica and amphibole peppering the lighter color minerals; some individual crystals 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 descriptive field term for lighter-colored, coarse-grained igneous rocks. Petrographic examination is required for identification of specific types of granitoids; the extrusive igneous rock equivalent of granite is rhyolite. Granite is nearly always massive and tough; these properties have made granite a widespread construction stone throughout human history. The average density of granite is between 2.65 and 2.75 g/cm3, its compressive strength lies above 200 MPa, its viscosity near STP is 3–6·1019 Pa·s. The melting temperature of dry granite at ambient pressure is 1215–1260 °C. Granite has poor primary permeability overall, but strong secondary permeability through cracks and fractures if they are present. Granite is classified according to the QAPF diagram for coarse grained plutonic rocks and is named according to the percentage of quartz, alkali feldspar and plagioclase feldspar on the A-Q-P half of the diagram.
True granite contains both alkali feldspars. When a granitoid is devoid or nearly devoid of plagioclase, the rock is referred to as alkali feldspar granite; when a granitoid contains less than 10% orthoclase, it is called tonalite. A granite containing both muscovite and biotite micas is called two-mica granite. Two-mica granites are high in potassium and low in plagioclase, are S-type granites or A-type granites. A worldwide average of the chemical composition of granite, by weight percent, based on 2485 analyses: Granite containing rock is distributed throughout the continental crust. Much of it was intruded during the Precambrian age. Outcrops of granite tend to form rounded massifs. Granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels. Granite occurs as small, less than 100 km2 stock masses and in batholiths that are associated with orogenic mountain ranges. Small dikes of granitic composition called aplites are associated with the margins of granitic intrusions.
In some locations coarse-grained pegmatite masses occur with granite. Granite is more common in continental crust than in oceanic crust, they are crystallized from felsic melts which are less dense than mafic rocks and thus tend to ascend toward the surface. In contrast, mafic rocks, either basalts or gabbros, once metamorphosed at eclogite facies, tend to sink into the mantle beneath the Moho. Granitoids have crystallized from felsic magmas that have compositions near a eutectic point. Magmas are composed of minerals in variable abundances. Traditionally, magmatic minerals are crystallized from the melts that have separated from their parental rocks and thus are evolved because of igneous differentiation. If a granite has a cooling process, it has the potential to form larger crystals. There are peritectic and residual minerals in granitic magmas. Peritectic minerals are generated through peritectic reactions, whereas residual minerals are inherited from parental rocks. In either case, magmas will evolve to the eutectic for crystallization upon cooling.
Anatectic melts are produced by peritectic reactions, but they are much less evolved than magmatic melts because they have not separated from their parental rocks. The composition of anatectic melts may change toward the magmatic melts through high-degree fractional crystallization. Fractional crystallisation serves to reduce a melt in iron, titanium and sodium, enrich the melt in potassium and silicon – alkali feldspar and quartz, are two of the defining constituents of granite; this process operates regardless of the origin of parental magmas to granites, regardless of their chemistry. 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 distinctive as to its parental rock. For instance, a granite, derived from partial melting of meta