Emergency medical services in the United Kingdom
Emergency medical services in the United Kingdom provide emergency care to people with acute illness or injury and are predominantly provided free at the point of use by the four National Health Services of England, Scotland and Northern Ireland. Emergency care including ambulance and emergency department treatment is free to everyone, regardless of immigration or visitor status; the NHS commissions most emergency medical services through the 14 NHS organisations with ambulance responsibility across the UK. As with other emergency services, the public access emergency medical services through one of the valid emergency telephone numbers. In addition to ambulance services provided by NHS organisations, there are some private and volunteer emergency medical services arrangements in place in the UK, the use of private or volunteer ambulances at public events or large private sites, as part of community provision of services such as community first responders. Air ambulance services in the UK are not part of the NHS and are funded through charitable donations.
Paramedics are seconded from a local NHS ambulance service, with the exception of Great North Air Ambulance Service who employ their own paramedics. Doctors are provided by their home hospital and spend no more than 40% of their time with an air ambulance service. Public ambulance services across the UK are required by law to respond to four types of requests for care, which are: Emergency calls Doctor's urgent admission requests High dependency and urgent inter-hospital transfers Major incidentsAmbulance trusts and services may undertake non-urgent patient transport services on a commercial arrangement with their local hospital trusts or health boards, or in some cases on directly funded government contracts, although these contracts are fulfilled by private and voluntary providers; the National Health Service Act 1946 gave county and borough councils a statutory responsibility to provide an emergency ambulance service, although they could contract a voluntary ambulance service to provide this, with many contracting the British Red Cross, St John Ambulance or another local provider.
The last St John Division, to be so contracted is reputed to have been at Whittlesey in Cambridgeshire, where the two-bay ambulance garage can still be seen at the branch headquarters. The Regional Ambulance Officers’ Committee reported in 1979 that “There was considerable local variation in the quality of the service provided in relation to vehicles and equipment. Most Services were administered by Local Authorities through their Medical Officer of Health and his Ambulance Officer, a few were under the aegis of the Fire Service, whilst others relied upon agency methods for the provision of part or all of their services.” The 142 existing ambulance services were transferred by the National Health Service Reorganisation Act 1973 from local authority to central government control in 1974, consolidated into 53 services under regional or area health authorities. This led to the formation of predominantly county based ambulance services, which merged up and changed responsibilities until 2006, when there were 31 NHS ambulance trusts in England.
The June 2005 report "Taking healthcare to the Patient", authored by Peter Bradley, Chief Executive of the London Ambulance Service, for the Department of Health led to the merging of the 31 trusts into 13 organisations in England, plus one organisation each in Wales and Northern Ireland. Following further changes as part of the NHS foundation trust pathway, this has further reduced to 10 ambulance service trusts in England, plus the Isle of Wight which has its own provision. Following the passage of the Health and Social Care Act 2012, commissioning of the ambulance services in each area passed from central government control into the hands of regional clinical commissioning groups; the commissioners in each region are responsible for contracting with a suitable organisation to provide ambulance services within their geographical territory. The primary provider for each area is held by a public NHS body, of which there are 11 in England, 1 each in the other three countries. In England there are now ten NHS ambulance trusts, as well as an ambulance service on the Isle of Wight, run directly by Isle of Wight NHS Trust, with boundaries following those of the former regional government offices.
The ten trusts are: East Midlands Ambulance Service NHS Trust East of England Ambulance Service NHS Trust London Ambulance Service NHS Trust North East Ambulance Service NHS Foundation Trust North West Ambulance Service NHS Trust South Central Ambulance Service NHS Foundation Trust South East Coast Ambulance Service NHS Foundation Trust South Western Ambulance Service NHS Foundation Trust West Midlands Ambulance Service University NHS Foundation Trust Yorkshire Ambulance Service NHS TrustThe English ambulance trusts are represented by the Association of Ambulance Chief Executives, with the Scottish and Northern Irish providers all associate members. On the 14 November 2018 West Midlands Ambulance Service became the UK's first university-ambulance trust; the service was operated before reorganisation in 1974 by the St Andrews’ Ambulance Association under contract to the Secretary of State for Scotland. The Scottish Ambulance Service is a Special Health Board that provides ambulance services throughout whole of Scotland, on behalf of the Health and Social Care Directorates of the Scottish Government.
Due to the remote nature of many areas of Scotland compared to the other Home Nations, the Scottish Ambulance Service has Britain's only publi
A defensive wall is a fortification used to protect a city, town or other settlement from potential aggressors. In ancient to modern times, they were used to enclose settlements; these are referred to as city walls or town walls, although there were walls, such as the Great Wall of China, Walls of Benin, Hadrian's Wall, Anastasian Wall, the Cyclopean Wall Rajgir and the metaphorical Atlantic Wall, which extended far beyond the borders of a city and were used to enclose regions or mark territorial boundaries. In mountainous terrain, defensive walls such as letzis were used in combination with castles to seal valleys from potential attack. Beyond their defensive utility, many walls had important symbolic functions – representing the status and independence of the communities they embraced. Existing ancient walls are always masonry structures, although brick and timber-built variants are known. Depending on the topography of the area surrounding the city or the settlement the wall is intended to protect, elements of the terrain such as rivers or coastlines may be incorporated in order to make the wall more effective.
Walls may only be crossed by entering the appropriate city gate and are supplemented with towers. The practice of building these massive walls, though having its origins in prehistory, was refined during the rise of city-states, energetic wall-building continued into the medieval period and beyond in certain parts of Europe. Simpler defensive walls of earth or stone, thrown up around hillforts, early castles and the like, tend to be referred to as ramparts or banks. From early history to modern times, walls have been a near necessity for every city. Uruk in ancient Sumer is one of the world's oldest known walled cities. Before that, the proto-city of Jericho in the West Bank in Palestine had a wall surrounding it as early as the 8th millennium BC; the Assyrians deployed large labour forces to build new palaces and defensive walls. Some settlements in the Indus Valley Civilization were fortified. By about 3500 BC, hundreds of small farming villages dotted the Indus floodplain. Many of these settlements had planned streets.
The stone and mud brick houses of Kot Diji were clustered behind massive stone flood dykes and defensive walls, for neighboring communities quarreled about the control of prime agricultural land. Mundigak in present-day south-east Afghanistan has defensive walls and square bastions of sun dried bricks. Babylon was one of the most famous cities of the ancient world as a result of the building program of Nebuchadnezzar, who expanded the walls and built the Ishtar Gate. Exceptions were few, but neither ancient Sparta nor ancient Rome had walls for a long time, choosing to rely on their militaries for defense instead; these fortifications were simple constructions of wood and earth, which were replaced by mixed constructions of stones piled on top of each other without mortar. In Central Europe, the Celts built large fortified settlements which the Romans called oppida, whose walls seem influenced by those built in the Mediterranean; the fortifications were continuously improved. In ancient Greece, large stone walls had been built in Mycenaean Greece, such as the ancient site of Mycenae.
In classical era Greece, the city of Athens built a long set of parallel stone walls called the Long Walls that reached their guarded seaport at Piraeus. Large rammed earth walls were built in ancient China since the Shang Dynasty, as the capital at ancient Ao had enormous walls built in this fashion. Although stone walls were built in China during the Warring States, mass conversion to stone architecture did not begin in earnest until the Tang Dynasty. Sections of the Great Wall had been built prior to the Qin Dynasty and subsequently connected and fortified during the Qin dynasty, although its present form was an engineering feat and remodeling of the Ming Dynasty; the large walls of Pingyao serve as one example. The walls of the Forbidden City in Beijing were established in the early 15th century by the Yongle Emperor; the Romans fortified their cities with mortar-bound stone walls. Among these are the extant Aurelian Walls of Rome and the Theodosian Walls of Constantinople, together with partial remains elsewhere.
These are city gates, like the Porta Nigra in Trier or Newport Arch in Lincoln. Apart from these, the early Middle Ages saw the creation of some towns built around castles; these cities were only protected by simple stone walls and more by a combination of both walls and ditches. From the 12th century AD hundreds of settlements of all sizes were founded all across Europe, which often obtained the right of fortification soon afterwards; the founding of urban centers was an important means of territorial expansion and many cities in central and eastern Europe, were founded for this purpose during the period of Eastern settlement. These cities are easy to recognise due to their regular layout and large market spaces; the fortifications of these settlements were continuously improved to reflect the current level of military development. During the Renaissance era, the Venetians raised great walls around cities threatened by the Ottoman Empire. Examples include the walled cities of Nicosia and Famagusta in Cyprus and the fortifications of Candia and Chania in Crete, which still stand.
At its simplest, a defensive wall consists of its gates. For the most part, the top of the walls were accessible, with the outside of the walls ha
Vikings were Norse seafarers speaking the Old Norse language, who during the late 8th to late 11th centuries and traded from their Northern European homelands across wide areas of Europe, explored westwards to Iceland and Vinland. The term is commonly extended in modern English and other vernaculars to the inhabitants of Norse home communities during what has become known as the Viking Age; this period of Nordic military and demographic expansion constitutes an important element in the early medieval history of Scandinavia, the British Isles, Kievan Rus' and Sicily. Facilitated by advanced sailing and navigational skills, characterised by the longship, Viking activities at times extended into the Mediterranean littoral, North Africa, the Middle East. Following extended phases of exploration and settlement, Viking communities and governments were established in diverse areas of north-western Europe, Belarus and European Russia, the North Atlantic islands and as far as the north-eastern coast of North America.
This period of expansion witnessed the wider dissemination of Norse culture, while introducing strong foreign cultural influences into Scandinavia itself, with profound developmental implications in both directions. Popular, modern conceptions of the Vikings—the term applied casually to their modern descendants and the inhabitants of modern Scandinavia—often differ from the complex picture that emerges from archaeology and historical sources. A romanticised picture of Vikings as noble savages began to emerge in the 18th century. Perceived views of the Vikings as alternatively violent, piratical heathens or as intrepid adventurers owe much to conflicting varieties of the modern Viking myth that had taken shape by the early 20th century. Current popular representations of the Vikings are based on cultural clichés and stereotypes, complicating modern appreciation of the Viking legacy; these representations are not always accurate — for example, there is no evidence that they wore horned helmets.
One etymology derives víking from the feminine vík, meaning "creek, small bay". Various theories have been offered that the word viking may be derived from the name of the historical Norwegian district of Viken, meaning "a person from Viken". According to this theory, the word described persons from this area, it is only in the last few centuries that it has taken on the broader sense of early medieval Scandinavians in general. However, there are a few major problems with this theory. People from the Viken area were not called'Viking' in Old Norse manuscripts, but are referred to as víkverir,'Vík dwellers'. In addition, that explanation could explain only the masculine and ignore the feminine, a serious problem because the masculine is derived from the feminine but hardly vice versa; the form occurs as a personal name on some Swedish runestones. The stone of Tóki víking was raised in memory of a local man named Tóki who got the name Tóki víking because of his activities as a viking; the Gårdstånga Stone uses the phrase "ÞeR drængaR waRu wiða unesiR i wikingu", referring to the stone's dedicatees as vikings.
The Västra Strö 1 Runestone has an inscription in memory of a Björn, killed when "i viking". In Sweden there is a locality known since the middle ages as Vikingstad; the Bro Stone was risen in memory of Assur, said to have protected the land from vikings. There is little indication of any negative connotation in the term before the end of the Viking Age. Another etymology, one that gained support in the early twenty-first century, derives Viking from the same root as Old Norse vika, f.'sea mile', originally'the distance between two shifts of rowers', from the root *weik or *wîk, as in the Proto-Germanic verb *wîkan,'to recede'. This is found in the Proto-Nordic verb *wikan,'to turn', similar to Old Icelandic víkja'to move, to turn', with well-attested nautical usages. Linguistically, this theory is better attested, the term most predates the use of the sail by the Germanic peoples of North-Western Europe, because the Old Frisian spelling shows that the word was pronounced with a palatal k and thus in all probability existed in North-Western Germanic before that palatalisation happened, that is, in the 5th century or before.
In that case, the idea behind it seems to be that the tired rower moves aside for the rested rower on the thwart when he relieves him. The Old Norse feminine víking may have been a sea journey characterised by the shifting of rowers, i.e. a long-distance sea journey, because in the pre-sail era, the shifting of rowers would distinguish long-distance sea journeys. A víkingr would originally have been a participant on a sea journey characterised by the shifting of rowers. In that case, the word Viking was not connected to Scandinavian seafarers but assumed this meaning when the Scandinavians begun to dominate the seas. In Old English, the word wicing appears first in the Anglo-Saxon poem, which dates from the 9th century. In Old English, in the history of the archbishops of Hamburg-Bremen written by Adam of Bremen in about 1070, the term referred to Scandi
The Iron Age is the final epoch of the three-age division of the prehistory and protohistory of humankind. It was preceded by the Bronze Age; the concept has been applied to Europe and the Ancient Near East, and, by analogy to other parts of the Old World. The duration of the Iron Age varies depending on the region under consideration, it is defined by archaeological convention, the mere presence of some cast or wrought iron is not sufficient to represent an Iron Age culture. For example, Tutankhamun's meteoric iron dagger comes from the Bronze Age. In the Ancient Near East, this transition takes place in the wake of the so-called Bronze Age collapse, in the 12th century BC; the technology soon spread to South Asia. Its further spread to Central Asia, Eastern Europe, Central Europe is somewhat delayed, Northern Europe is reached still by about 500 BC; the Iron Age is taken to end by convention, with the beginning of the historiographical record. This does not represent a clear break in the archaeological record.
The Germanic Iron Age of Scandinavia is taken to end c. AD 800, with the beginning of the Viking Age. In South Asia, the Iron Age is taken to begin with the ironworking Painted Gray Ware culture and to end with the reign of Ashoka; the use of the term "Iron Age" in the archaeology of South and Southeast Asia is more recent, less common, than for western Eurasia. The Sahel and Sub-Saharan Africa are outside of the three-age system, there being no Bronze Age, but the term "Iron Age" is sometimes used in reference to early cultures practicing ironworking such as the Nok culture of Nigeria; the three-age system was introduced in the first half of the 19th century for the archaeology of Europe in particular, by the 19th century expanded to the archaeology of the Ancient Near East. Its name harks back to the mythological "Ages of Man" of Hesiod; as an archaeological era it was first introduced for Scandinavia by Christian Jürgensen Thomsen in the 1830s. By the 1860s, it was embraced as a useful division of the "earliest history of mankind" in general and began to be applied in Assyriology.
The development of the now-conventional periodization in the archaeology of the Ancient Near East was developed in the 1920s to 1930s. As its name suggests, Iron Age technology is characterized by the production of tools and weaponry by ferrous metallurgy, more from carbon steel; the Iron Age in Europe is being seen as a part of the Bronze Age collapse in the ancient Near East, in ancient India, ancient Iran, ancient Greece. In other regions of Europe the Iron Age began in the 8th century BC in Central Europe and the 6th century BC in Northern Europe; the Near Eastern Iron Age is divided into two subsections, Iron I and Iron II. Iron I illustrates both discontinuity with the previous Late Bronze Age. There is no definitive cultural break between the 13th and 12th centuries BC throughout the entire region, although certain new features in the hill country and coastal region may suggest the appearance of the Aramaean and Sea People groups. There is evidence, however, of strong continuity with Bronze Age culture, although as one moves into Iron I the culture begins to diverge more from that of the late 2nd millennium.
The Iron Age as an archaeological period is defined as that part of the prehistory of a culture or region during which ferrous metallurgy was the dominant technology of metalworking. The periodization is not tied to the presence of ferrous metallurgy and is to some extent a matter of convention; the characteristic of an Iron Age culture is mass production of tools and weapons made from steel alloys with a carbon content between 0.30% and 1.2% by weight. Only with the capability of the production of carbon steel does ferrous metallurgy result in tools or weapons that are equal or superior to bronze. To this day bronze and brass have not been replaced in many applications, with the spread of steel being based as much on economics as on metallurgical advancements. A range of techniques have been used to produce steel from smelted iron, including techniques such as case-hardening and forge welding that were used to make cutting edges stronger. By convention, the Iron Age in the Ancient Near East is taken to last from c. 1200 BC to c. 550 BC, taken as the beginning of historiography or the end of the proto-historical period.
In Central and Western Europe, the Iron Age is taken to last from c. 800 BC to c. 1 BC, in Northern Europe from c. 500 BC to 800 AD. In China, there is no recognizable prehistoric period characterized by ironworking, as Bronze Age China transitions directly into the Qin dynasty of imperial China; the following gives an overview over the
England is a country, part of the United Kingdom. It shares land borders with Wales to Scotland to the north-northwest; the Irish Sea lies west of England and the Celtic Sea lies to the southwest. England is separated from continental Europe by the North Sea to the east and the English Channel to the south; the country covers five-eighths of the island of Great Britain, which lies in the North Atlantic, includes over 100 smaller islands, such as the Isles of Scilly and the Isle of Wight. The area now called England was first inhabited by modern humans during the Upper Palaeolithic period, but takes its name from the Angles, a Germanic tribe deriving its name from the Anglia peninsula, who settled during the 5th and 6th centuries. England became a unified state in the 10th century, since the Age of Discovery, which began during the 15th century, has had a significant cultural and legal impact on the wider world; the English language, the Anglican Church, English law – the basis for the common law legal systems of many other countries around the world – developed in England, the country's parliamentary system of government has been adopted by other nations.
The Industrial Revolution began in 18th-century England, transforming its society into the world's first industrialised nation. England's terrain is chiefly low hills and plains in central and southern England. However, there is upland and mountainous terrain in the west; the capital is London, which has the largest metropolitan area in both the United Kingdom and the European Union. England's population of over 55 million comprises 84% of the population of the United Kingdom concentrated around London, the South East, conurbations in the Midlands, the North West, the North East, Yorkshire, which each developed as major industrial regions during the 19th century; the Kingdom of England – which after 1535 included Wales – ceased being a separate sovereign state on 1 May 1707, when the Acts of Union put into effect the terms agreed in the Treaty of Union the previous year, resulting in a political union with the Kingdom of Scotland to create the Kingdom of Great Britain. In 1801, Great Britain was united with the Kingdom of Ireland to become the United Kingdom of Great Britain and Ireland.
In 1922 the Irish Free State seceded from the United Kingdom, leading to the latter being renamed the United Kingdom of Great Britain and Northern Ireland. 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. The Angles came from the Anglia peninsula in the Bay of Kiel area of the Baltic Sea; 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 used in a different sense to the modern one, meaning "the land inhabited by the English", it included English people in what is now south-east Scotland but was part of 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 the Chronicle stated that King Malcolm III went "out of Scotlande into Lothian in Englaland", thus using it in the more ancient sense.
According to the Oxford English Dictionary, its modern spelling was first used in 1538. The earliest attested reference to the Angles occurs in the 1st-century work by Tacitus, Germania, in which the Latin word Anglii is used; the etymology of the tribal name itself is disputed by scholars. How and why a term derived from the name of a tribe, less significant than others, such as the Saxons, came to be used for the entire country and its people is not known, but it seems this is related to the custom of calling the Germanic people in Britain Angli Saxones or English Saxons to distinguish them from continental Saxons of Old Saxony between the Weser and Eider rivers in Northern Germany. In Scottish Gaelic, another language which developed on the island of Great Britain, the Saxon tribe gave their name to the word for England. An alternative name for England is Albion; the name Albion referred to the entire island of Great Britain. The nominally earliest record of the name appears in the Aristotelian Corpus the 4th-century BC De Mundo: "Beyond the Pillars of Hercules is the ocean that flows round the earth.
In it are two large islands called Britannia. But modern scholarly consensus ascribes De Mundo not to Aristotle but to Pseudo-Aristotle, i.e. it was written in the Graeco-Roman period or afterwards. The word Albion or insula Albionum has two possible origins, it either derives from a cognate of the Latin albus meaning white, a reference to the white cliffs of Dover or from the phrase the "island of the Albiones" in the now lost Massaliote Periplus, attested through Avienus' Ora Maritima to which the former served as a source. Albion is now applied to England in a more poetic capacity. Another romantic name for England is Loegria, related to the Welsh word for England and made popular by its use in Arthurian legend; the earliest known evidence of human presence in the area now known as England was that of Homo antecessor, dating to approximate
Miller of Dee
There Was a Jolly Miller Once is a traditional folk song from the Chester area in northwest England. It is titled "The Miller of the Dee" or "The Jolly Miller"; the song was part of Isaac Bickerstaffe's play, Love in a Village. Subsequently, other versions of Bickerstaffe's original song were made by various other poets; the city of Chester stands on the River Dee and a weir was built across the river here in the Middle Ages to maintain high water levels for several water mills which stood on its banks. The River Dee rises on the eastern slopes of Dduallt in Snowdonia and enters the Dee Estuary on the outskirts of Chester; the English name for the river is derived from Afon Dyfrdwy. Its Latin name was Deva; the song is sung to the Welsh harp tune Llydaw. Many settings of the tune have been made by British composers, most notably Benjamin Britten in volume three of his Folk-song arrangements. Roger Quilter's setting of the song was included in the Arnold Book of Old Songs, published in 1950. Several versions for choir exist, such as that by John Rutter.
In 1962 Havergal Brian wrote a comedy overture for orchestra based on the tune. A 1997 local interest book on the history of the Mills and Millers in Chester was named after this folk song.... There dwelt a miller and bold, beside the river Dee. There was a jolly miller once Lived on the River Dee He danced and he sang from morn till night No lark so blithe as he, and this the burden of his song For used to be I care for nobody, no, not I, If nobody cares for me. I live by my mill, God bless her! She's kindred and wife I would not change my station For any other in life. No lawyer, surgeon, or doctor E'er had a groat from me I care for nobody, no, not I, If nobody cares for me; when Spring begins its merry career Oh! How his heart grows gay No summer drought alarms his fears Nor winter's sad decay No foresight mars the miller's joy Who's wont to sing and say Let others toil from year to year I live from day to day, thus like the miller and free Let us rejoice and sing The days of youth are made for glee And time is on the wing.
This song shall pass from me to thee Along this jovial ring Let heart and voice and all agree to say Long live the King. This version was published in The Convivial Songster in 1782. There was a jolly miller once Lived on the River Dee, and this the burden of his song Forever used to be. The reason why he was so blithe, He once did thus unfold. I care for nobody, no, not I. A coin or two I've in my purse. Though I may fail, yet I rejoice, Another's good hap to see. I care for nobody, no, not I. So let us his example take, and merrily push the can about And drink and sing with glee. This version was discovered in 1857 written on a flyleaf of a 1716 collection of John Dryden's poems. There dwelt a miller and bold, Beside the River Dee, and tell me now, what makes thee sing, With voice so loud and free, While I am sad, though I'm the King, Beside the river Dee?'The miller smiled and doff'd his cap, "I earn my bread," quoth he. This version was written by Charles Mackay. Rod Steiger, playing serial killer Christopher Gill, whistled "The Miller of Dee" several times in the 1968 film No Way to Treat a Lady.
As well as this, Robert Newton sung an alternative version in the 1952 film Blackbeard the Pirate.
Sandstone is a clastic sedimentary rock composed of sand-sized mineral particles or rock fragments. Most sandstone is composed of quartz or feldspar because they are the most resistant minerals to weathering processes at the Earth's surface, as seen in Bowen's reaction series. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, yellow, grey, pink and black. Since sandstone beds form visible cliffs and other topographic features, certain colors of sandstone have been identified with certain regions. Rock formations that are composed of sandstone allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Fine-grained aquifers, such as sandstones, are better able to filter out pollutants from the surface than are rocks with cracks and crevices, such as limestone or other rocks fractured by seismic activity. Quartz-bearing sandstone can be changed into quartzite through metamorphism related to tectonic compression within orogenic belts.
Sandstones are clastic in origin. They are formed from cemented grains that may either be fragments of a pre-existing rock or be mono-minerallic crystals; the cements binding these grains together are calcite and silica. Grain sizes in sands are defined within the range of 0.0625 mm to 2 mm. Clays and sediments with smaller grain sizes not visible with the naked eye, including siltstones and shales, are called argillaceous sediments; the formation of sandstone involves two principal stages. First, a layer or layers of sand accumulates as the result of sedimentation, either from water or from air. Sedimentation occurs by the sand settling out from suspension. Once it has accumulated, the sand becomes sandstone when it is compacted by the pressure of overlying deposits and cemented by the precipitation of minerals within the pore spaces between sand grains; the most common cementing materials are silica and calcium carbonate, which are derived either from dissolution or from alteration of the sand after it was buried.
Colors will be tan or yellow. A predominant additional colourant in the southwestern United States is iron oxide, which imparts reddish tints ranging from pink to dark red, with additional manganese imparting a purplish hue. Red sandstones are seen in the Southwest and West of Britain, as well as central Europe and Mongolia; the regularity of the latter favours use as a source for masonry, either as a primary building material or as a facing stone, over other forms of construction. The environment where it is deposited is crucial in determining the characteristics of the resulting sandstone, which, in finer detail, include its grain size and composition and, in more general detail, include the rock geometry and sedimentary structures. Principal environments of deposition may be split between terrestrial and marine, as illustrated by the following broad groupings: Terrestrial environmentsRivers Alluvial fans Glacial outwash Lakes Deserts Marine environmentsDeltas Beach and shoreface sands Tidal flats Offshore bars and sand waves Storm deposits Turbidites Framework grains are sand-sized detrital fragments that make up the bulk of a sandstone.
These grains can be classified into several different categories based on their mineral composition: Quartz framework grains are the dominant minerals in most clastic sedimentary rocks. These physical properties allow the quartz grains to survive multiple recycling events, while allowing the grains to display some degree of rounding. Quartz grains evolve from plutonic rock, which are felsic in origin and from older sandstones that have been recycled. Feldspathic framework grains are the second most abundant mineral in sandstones. Feldspar can be divided into two smaller subdivisions: plagioclase feldspars; the different types of feldspar can be distinguished under a petrographic microscope. Below is a description of the different types of feldspar. Alkali feldspar is a group of minerals in which the chemical composition of the mineral can range from KAlSi3O8 to NaAlSi3O8, this represents a complete solid solution. Plagioclase feldspar is a complex group of solid solution minerals that range in composition from NaAlSi3O8 to CaAl2Si2O8.
Lithic framework grains are pieces of ancient source rock that have yet to weather away to individual mineral grains, called lithic fragments or clasts. Lithic fragments can be any fine-grained or coarse-grained igneous, metamorphic, or sedimentary rock, although the most common lithic fragments found in sedimentary rocks are clasts of volcanic rocks. Accessory minerals are all other mineral grains in a sandstone. Common accessory minerals include micas, olivine and corundum. Many of these accessory grains are more dense than the silicates that