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{{Nofootnotes|date=February 2008}}
Great BritainGreat Britain is an island lying to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island. With a population of about 59.6 million people, it is the third most populated island on Earth. Great Britain is surrounded by over 1000 smaller...
shows a rich variety of
landscapeLandscape comprises the visible features of an area of land, including physical elements such as landforms, living elements of flora and fauna, abstract elements like lighting and weather conditions, and human elements like human activity and the built environment.-Etymology:The word landscape...
across the constituent countries of
EnglandEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west and the North Sea to the east, with the English Channel to the south separating it from continental...
,
WalesWales is a country that is part of the United Kingdom, bordered by England to its east, and the Atlantic Ocean and Irish Sea to its west. It is also an elective region of the European Union...
and
ScotlandScotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
. Landforms and rocks of all geological ages are represented, from
PrecambrianThe Precambrian is an informal name for the span of time before the current Phanerozoic Eon, and is divided into several eons of the geologic timescale. It spans from the formation of Earth around 4500 Ma to the beginning of the Cambrian Period, when macroscopic hard-shelled animals first...
onwards.
Seismographical results
SeismographicalSeismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth...
research shows that the
crustIn geology, a crust is the outermost solid shell of a rocky planet or moon, which is chemically distinct from the underlying mantle. The crusts of Earth, our Moon, Mercury, Venus, Mars, Io, and other planetary bodies have been generated largely by igneous processes, and these crusts are richer in...
of the
EarthEarth is the third planet from the Sun. It is the fifth largest of the eight planets in the solar system, and the largest of the terrestrial planets in the Solar System in terms of diameter, mass and density...
below
Great BritainGreat Britain is an island lying to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island. With a population of about 59.6 million people, it is the third most populated island on Earth. Great Britain is surrounded by over 1000 smaller...
is between 27 and 35 km (17 to 22 miles) thick. The oldest rocks are found at the surface in north west
ScotlandScotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
and are more than half as old as the
planetA planet , is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
. They are thought to underlie much of
Great BritainGreat Britain is an island lying to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island. With a population of about 59.6 million people, it is the third most populated island on Earth. Great Britain is surrounded by over 1000 smaller...
and
IrelandIreland is the third-largest island in Europe and the twentieth-largest island in the world. It lies to the north-west of continental Europe and is surrounded by hundreds of islands and islets. To the east of Ireland, separated by the Irish Sea, is the island of Great Britain...
(although boreholes have only penetrated the first few kilometres), but next appear extensively at the surface in
BrittanyBrittany is a cultural and administrative region in the north-west of France. Brittany was previously a kingdom and then as a duchy it was a fief of the Kingdom of France. It was at one time called Less, Lesser or Little Britain...
and the
Channel IslandsThe Channel Islands are an archipelago in the English Channel, off the French coast of Normandy. They include two separate bailiwicks: the Bailiwick of Guernsey and the Bailiwick of Jersey...
. The youngest rocks are found in south east
EnglandEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west and the North Sea to the east, with the English Channel to the south separating it from continental...
.
Bedrock
The
bedrockIn stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...
consists of layers formed over vast periods of time. These were laid down as the
climateClimate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and numerous other meteorological elements in a given region over long periods of time...
changed, the landmasses moved due to
plate tectonicsPlate tectonics is a theory which describes the large scale motions of Earth's lithosphere...
, and the land and sea levels rose or fell. From time to time horizontal forces caused the rock to undergo deformation, folding the layers of rock to form mountains which have since been
erodedErosion is a gravity driven process that moves solids in the natural environment or their source and deposits them elsewhere...
and overlain with other layers. To further complicate the geology, the land has also been subject to periods of
earthquakeAn earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are recorded with a seismometer, also known as a seismograph...
s and volcanic activity.
Deposits by glaciers
Overprinted on this
bedrockIn stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...
geology ("solid geology" in the terminology of maps) is a distribution of soils and fragmental material deposited by glaciers (
boulder clayBoulder clay, in geology, is a deposit of clay, often full of boulders, which is formed in and beneath glaciers and ice-sheets wherever they are found, but is in a special sense the typical deposit of the Glacial Period in northern Europe and North America. Boulder clay is variously known as till...
, and other forms of glacial drift in the recent past. "Drift" geology is often more important than "solid" geology when considering such as building works, drainage, siting water boreholes, sand and gravel resources and soil fertility. Although "drift" strictly refers to glacial and fluvio-glacial deposits, the term on geological maps has traditionally included other material including alluvium, river terraces, etc. Recent maps use the terms "bedrock" and "superficial" in place of "solid" and "drift".
Proterozoic Era
The
GneissGneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks. Gneissic rocks are usually medium to coarse foliated and largely recrystallized but do not carry large...
es, the oldest rocks in
Great BritainGreat Britain is an island lying to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island. With a population of about 59.6 million people, it is the third most populated island on Earth. Great Britain is surrounded by over 1000 smaller...
or
IrelandIreland is the third-largest island in Europe and the twentieth-largest island in the world. It lies to the north-west of continental Europe and is surrounded by hundreds of islands and islets. To the east of Ireland, separated by the Irish Sea, is the island of Great Britain...
, date from at least 2,700 Ma (Ma = million years ago) in the Archaean period of this era, the
EarthEarth is the third planet from the Sun. It is the fifth largest of the eight planets in the solar system, and the largest of the terrestrial planets in the Solar System in terms of diameter, mass and density...
itself being about 4,600 Ma old. They are found in the far north west of
ScotlandScotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
and in the
HebridesThe Hebrides comprise a widespread and diverse archipelago off the west coast of Scotland. There are two main groups: the Inner and Outer Hebrides...
, with a few small outcrops elsewhere. Formed from rock originally deposited at the surface of the planet, the rocks were later buried deep in the Earth's crust and
metamorphosedMetamorphic rock is the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
into crystalline gneiss.
South of the Gneisses are a complex mixture of rocks forming the North West
HighlandsThe Scottish Highlands include the rugged and mountainous regions of Scotland north and west of the Highland Boundary Fault, although the exact boundaries are not clearly defined, particularly to the east...
and
GrampianGrampian was a local government region of Scotland from 1975 to 1996. It is now divided into the unitary council areas of:*Moray*Aberdeenshire*City of AberdeenThe region had five districts:*Aberdeen*Banff and Buchan...
Highlands in Scotland, as well as the
ConnemaraConnemara , which derives from Conmhaicne Mara , is a district in the west of Ireland consisting of a broad peninsula between Killary Harbour and Kilkieran Bay in the west of County Galway or south west Connacht...
,
DonegalDonegal is a town in County Donegal, in the Province of Ulster, in Ireland. Donegal is not the county town of County Donegal, despite being its namesake. Rather, the county town is Lifford, and Letterkenny is the county's largest town. Donegal town is situated at the mouth of Donegal Bay, on the...
and
MayoCounty Mayo is one of the traditional counties of Ireland and is located within the province of Connacht. It was named after the village of Mayo . Mayo is the secondlargest of Ireland’s 32 counties in area and 15th largest in terms of population...
mountains of Ireland. These are essentially the remains of folded
sedimentary rockSedimentary rock is the type of rock that is formed by sedimentation of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
s that were originally 25 km thick, deposited over the gneiss on what was then the floor of the
Iapetus OceanThe Iapetus Ocean was an ocean that existed in the Neoproterozoic and Paleozoic eras of the geologic timescale . The Iapetus Ocean was situated in the southern hemisphere, between the paleocontinents of Laurentia, Baltica and Avalonia...
. The process started in about 1,000 Ma, with a notable 7 km thick layer of Torridon Sandstone being deposited about 800 Ma, as well as the
debrisA moraine is any glacially formed accumulation of unconsolidated glacial debris which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past ice age. This debris may have been plucked off the valley floor as a glacier advanced or it may have...
deposited by an
ice sheetAn ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² . The only current ice sheets are in Antarctica and Greenland; during the last glacial period at Last Glacial Maximum the Laurentide ice sheet covered much of Canada and North America, the...
670 Ma.
Palaeomagnetic evidence indicates that 520 Ma, what is now the UK was split between two
continentA continent is one of several large landmasses on Earth. They are generally identified by convention rather than any strict criterion, with seven regions commonly regarded as continents – they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...
s, separated by 7000 km (4500 miles) of ocean. The north of Scotland was located at about 20° south of the
equatorThe equator is the intersection of the Earth's surface with the plane perpendicular to the Earth's axis of rotation and containing the Earth's center of mass. In simpler language, it is an imaginary line on the Earth's surface equidistant from the North Pole and South Pole that divides the Earth...
on the continent of
LaurentiaLaurentia , like all craton land, was created as continents moved about the surface of the Earth, bumping into other continents and drifting away....
near the
Tropic of CapricornThe Tropic of Capricorn, or Southern tropic, is one of the five major circles of latitude that mark maps of the Earth. It lies 23° 26′ 22″ south of the equator, and marks the most southerly latitude at which the sun can appear directly overhead at noon...
, while the rest of the country was at about 60° south on the continent of
GondwanaGondwana , originally Gondwanaland, is the name given to a southern precursor-supercontinent. Its final joining occurred between ca. 570 and 510 Ma ago, joining East Gondwana to West Gondwana. It later separated from Laurasia 180- during the breakup of the Pangaea supercontinent that existed about...
near the
Antarctic CircleThe Antarctic Circle is one of the five major circles of latitude that mark maps of the Earth. As of , it lies at latitude 66° 33′ 39″ south of the equator. The area south of the Antarctic Circle is known as the Antarctic, and the zone immediately to the north is called the Southern Temperate Zone...
.
In Gondwana, England and
WalesWales is a country that is part of the United Kingdom, bordered by England to its east, and the Atlantic Ocean and Irish Sea to its west. It is also an elective region of the European Union...
were near a
subductionIn geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. A subduction zone is an area on Earth where two tectonic plates move towards one another and...
zone. Both countries were largely submerged under a shallow sea studded with
volcanic3. Conduit
4. Base
5. Sill
6. Dike
7. Layers of ash emitted by the volcano
8. Flank| 9. Layers of lava emitted by the volcano
10. Throat
11. Parasitic cone
12. Lava flow
13. Vent
14. Crater
15...
islands. The remains of these islands underlie much of central England with small outcrops visible in many places. Around 600 Ma, the
Cadomian OrogenyThe Cadomian Orogeny was a tectonic event or series of events in the late Neoproterozoic, about 650-550 Ma, which probably included the formation of mountains. This occurred on the margin of the Gondwana continent, involving one or more collisions of island arcs and accretion of other material at a...
(mountain building period) caused the English and Welsh landscape to be transformed into a mountainous region, along with much of north west
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
.
Cambrian period
In the early
CambrianThe Cambrian is the first geological period of the Paleozoic era, lasting from ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux...
period the volcanoes and mountains of England and Wales were eroded as the land became flooded by a rise in sea level, and new layers of
sedimentSediment is any particulate matter that can be transported by fluid flow, and which eventually is deposited.Sediments are most often transported by water transported by wind and glaciers...
were laid down. Much of central England formed a stable block of crust which has remained largely undeformed ever since.
SandstoneSandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow,...
s were deposited in the north of Scotland. As this is when the first hard shells evolved,
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
s become much more common from this period onwards.
Ordovician period
500 million years ago, in the
OrdovicianThe Ordovician is a geologic period and system, the second of six of the Paleozoic era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian period and is followed by the Silurian period...
period, southern Britain, the east coast of
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
and south-east Newfoundland broke away from Gondwana to form the continent of
AvaloniaAvalonia is a former microcontinent, and the region of its Avalon terrane. It underlies south-west Great Britain, and the eastern coast of North America. It is the source of many of the older rocks of Western Europe, Atlantic Canada, and parts of the coastal United States...
, which by 440 Ma had drifted (by the mechanisms of
plate tectonicsPlate tectonics is a theory which describes the large scale motions of Earth's lithosphere...
) to about 30° south.
During this period north Wales and south Mayo experienced volcanic activity. The remains of these volcanoes are still visible, for example
Rhobell Fawr|}Rhobell Fawr is an extinct volcano in the Arenig range within the Snowdonia National Park.Despite its modest height of 734 m , it is a mountain with superb views of higher peaks all around, including the superb north face of Cadair Idris and distant Snowdon.The immediate surroundings...
, dating from 510 Ma. Large quantities of volcanic
lavaLava is molten rock expelled by a volcano during eruption. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at temperatures from 700 °C to 1,200 °C...
and ash known as the
Borrowdale VolcanicsThe Borrowdale Volcanic Group is a volcanic group of rock formations named after the Borrowdale area of the Lake District, in England. They are late Ordovician in age . It is thought that they represent the remains of a volcanic island arc, approximately similar to the island arcs of the west...
covered both Wales and the
Lake DistrictThe Lake District, also known as The Lakes or Lakeland, is a rural area in North West England. A popular holiday destination, it is famous for its lakes and its mountains , and its associations with the early 19th century poetry and writings of William Wordsworth and the Lake Poets.The central and...
, still seen in the form of mountains such as
Helvellyn|}Helvellyn is a mountain in the English Lake District, the apex of the Eastern Fells. At above sea level, it is the third highest peak in both the Lake District and England.-Topography:...
and
Scafell Pike|}At 978 metres , Scafell Pike is the highest mountain in England. It is located in the Lake District National Park in Cumbria....
.
The Ordovician also saw the formation of the Welsh
Skiddaw|}Skiddaw is a mountain in the Lake District National Park in the United Kingdom. With a summit at 931 m above sea level it is the fourth highest mountain in England , and the lowest above...
slateSlate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary...
deposits around 500 Ma.
Silurian period
Deposition continued into the early part of the
SilurianThe Silurian is a geologic period and system that extends from the end of the Ordovician period, about 443.7 ± 1.5 Ma , to the beginning of the Devonian period, about 416.0 ± 2.8 Ma . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
period, with mudstones and sandstones being laid down, notably in Wales.
AvaloniaAvalonia is a former microcontinent, and the region of its Avalon terrane. It underlies south-west Great Britain, and the eastern coast of North America. It is the source of many of the older rocks of Western Europe, Atlantic Canada, and parts of the coastal United States...
had now joined with the continent of
BalticaBaltica is a name applied by geologists to a late-Proterozoic, early-Palaeozoic continent that now includes the East European craton of northwestern Eurasia. Baltica was created as an entity not earlier than 1.8 billion years ago. Before this time, the three segments/continents that now comprise...
, and the combined landmass collided with
LaurentiaLaurentia , like all craton land, was created as continents moved about the surface of the Earth, bumping into other continents and drifting away....
at about 20° south between 425 and 400 Ma, joining the southern and northern halves of
Great BritainGreat Britain is an island lying to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island. With a population of about 59.6 million people, it is the third most populated island on Earth. Great Britain is surrounded by over 1000 smaller...
together. The resulting
Caledonian OrogenyThe Caledonian orogeny is a mountain building era recorded in the northern parts of the British Isles, western Scandinavia, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occurred from the Ordovician to Early Devonian, roughly 490-390...
produced an
AlpineThe Alps are one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east; through Italy, Switzerland, Liechtenstein and Germany; to France in the west....
-style mountain range in much of north and west Britain. The continental collision was probably at an oblique angle rather than a head-on collision, and this probably led to movement along strike-slip faults trending north-east to south-west across Scotland, the
Great Glen FaultThe Great Glen Fault is a long strike-slip fault that runs through its namesake the Great Glen in Scotland. However, the fault is actually much longer and over 400 million years old.-Location:...
being the best example (some of these fault zones may have been old lines of weakness from earlier earth movements).
Volcanic ashes and lavas deposited during the Silurian are still found in the
Mendip HillsThe Mendip Hills are a range of limestone hills situated to the south of Bristol and Bath in Somerset, England. Running east to west between Weston-super-Mare and Frome, the Hills overlook the Somerset Levels to the south and the Avon valley to the north...
and in
PembrokeshirePembrokeshire is a county in the southwest of Wales.-Geography:Pembrokeshire is a maritime county, bordered by the sea on three sides, by Ceredigion to the north east and by Carmarthenshire to the east...
.
Devonian period
The collision between continents continued during the Devonian period, with continuing uplift, and more volcanic deposits such as those now forming
Ben NevisBen Nevis is the highest mountain in the British Isles. It is located at the western end of the Grampian Mountains in the Lochaber area of Scotland, close to the town of Fort William....
. Sea levels varied considerably, with the coastline advancing and retreating from north to south across England. The uplifted region was gradually eroded down, resulting in the deposition of numerous sedimentary rock layers in lowlands and seas. The rocks of marine origin in the county of
DevonDevon is a large county in England. The county is also referred to as Devonshire, although that is an unofficial name, rarely used inside of the county itself and often indicating a traditional or historical context. The county shares borders with Cornwall to the west and Dorset and Somerset to...
gave the period its name, though deposits of this age are found in many other places, such as the
Brecon BeaconsThe Brecon Beacons is a mountain range in South Wales. It forms the central section of the Brecon Beacons National Park , one of Wales's three National Parks.-Range:...
, the
Midland ValleyThe Central Lowlands or Midland Valley is a geologically defined area of relatively low-lying land in southern Scotland. It consists of a rift valley between the Highland Boundary Fault to the north and the Southern Uplands Fault to the south...
of Scotland, and the
Orkney IslandsOrkney, also known as the Orkney Islands, , is an archipelago in northern Scotland, situated 10 miles north of the coast of Caithness...
. Most of these are of terrestrial origin and are informally known as the
Old Red SandstoneThe Old Red Sandstone is a British rock formation of considerable importance to early paleontology. For convenience the short version of the term, 'ORS' is often used in literature on the subject.-Sedimentology:...
.
The Caledonian mountains had largely been
erodedErosion is a gravity driven process that moves solids in the natural environment or their source and deposits them elsewhere...
away by the end of the period during which the country would have experienced an arid
desertA desert is a landscape or region that receives almost no precipitation. Deserts are defined as areas with an average annual precipitation of less than per year, or as areas where more water is lost by evapotranspiration than falls as precipitation. In the Köppen climate classification system,...
climateClimate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and numerous other meteorological elements in a given region over long periods of time...
and been located between 10° and 15° south of the
equatorThe equator is the intersection of the Earth's surface with the plane perpendicular to the Earth's axis of rotation and containing the Earth's center of mass. In simpler language, it is an imaginary line on the Earth's surface equidistant from the North Pole and South Pole that divides the Earth...
.
Carboniferous period
Around 360 Ma during the
CarboniferousThe Carboniferous is a geologic period and system that extends from the end of the Devonian period, about 359.2 ± 2.5 Ma , to the beginning of the Permian period, about 299.0 ± 0.8 Ma ....
period Great Britain was lying at the equator, covered by the warm shallow waters of the
Rheic OceanThe Rheic Ocean was a Paleozoic ocean between the large continent Gondwana to the south and the microcontinents Avalonia and others to the north...
, during which time the Carboniferous Limestone was deposited, as found in the
Mendip HillsThe Mendip Hills are a range of limestone hills situated to the south of Bristol and Bath in Somerset, England. Running east to west between Weston-super-Mare and Frome, the Hills overlook the Somerset Levels to the south and the Avon valley to the north...
, north and south Wales, in the
Peak DistrictThe Peak District is an upland area in central and northern England, lying mainly in northern Derbyshire, but also covering parts of Cheshire, Greater Manchester, Staffordshire, and South and West Yorkshire....
of
DerbyshireDerbyshire is a county in the East Midlands of England. A substantial portion of the Peak District National Park lies within Derbyshire. The northern part of Derbyshire overlaps with the Pennines, a famous chain of hills and mountains...
, north
LancashireLancashire is a non-metropolitan county of historic origin in the North West of England. It takes its name from the city of Lancaster, and is sometimes known as the County of Lancaster. Lancashire County Council is based in Preston. However, Lancaster is still considered to be the county town...
, the northern
PenninesThe Pennines are a low-rising mountain range in northern England and southern Scotland. They separate the North West of England from Yorkshire and the North East....
and southeast Scotland. Caves have developed more recently in the limestone in some of these areas.
These were followed by dark marine
shalesShalës is a municipality in the Elbasan District, Elbasan County, central Albania....
, siltstones, and coarse sandstones of the Millstone Grit. Later,
river deltaA delta is a landform that is created at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
s formed and the sediments deposited were colonised by
swampA swamp is a wetland featuring temporary or permanent inundation of large areas of land by shallow bodies of water. A swamp generally has a substantial number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types...
s and rain forest. It was in this environment that the
cyclicCyclic sediments are sequences of sedimentary rocks that are characterised by repetitive patterns of different rock types within the sequence. Cyclic sediments can be identified as either autocyclic or allocyclic, and can be hundreds or even thousands of metres thick...
Coal Measures were formed, the source of the majority of Britain's extensive
coalCoal is a readily combustible black or brownish-black sedimentary rock normally occurring in rock strata in layers or veins called coal beds. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
reserves that powered the
Industrial RevolutionThe Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, and transport had a profound effect on the socioeconomic and cultural conditions in the United Kingdom. The changes subsequently spread throughout Europe, North...
. Coal can be found in many areas of Britain and Ireland, as far north as the Midland Valley of
ScotlandScotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
, as far south as
KentKent , originally Cantia, is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the River Thames estuary. The ceremonial county boundaries of Kent include the shire county of Kent...
and in Ireland, though it has largely been mined in the
English midlandsThe English Midlands, or the Midlands is the traditional name for the area comprising central England that broadly corresponds to the early medieval Kingdom of Mercia. It borders Southern England, Northern England, East Anglia and Wales. Its largest city is Birmingham, and it was an important...
, northern England and Wales.
Throughout the period, southwest England in particular was affected by the collision of continental plates. The
Variscan orogenyThe Variscan orogeny is a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica and Gondwana to form the supercontinent of Pangaea.-Naming:...
(mountain building period) around 280 Ma caused major deformation in south west England. Towards its end
graniteGranite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite has a medium to coarse texture, occasionally with some individual crystals larger than the groundmass forming a rock known as porphyry. Granites can be pink to dark gray or even black, depending on their...
was formed beneath the overlying rocks of
DevonDevon is a large county in England. The county is also referred to as Devonshire, although that is an unofficial name, rarely used inside of the county itself and often indicating a traditional or historical context. The county shares borders with Cornwall to the west and Dorset and Somerset to...
and
CornwallCornwall is a county of England in the United Kingdom, forming the tip of the south-western peninsula of Great Britain. It is bordered to the north and west by the Atlantic Ocean, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Taken with the...
, now exposed as
DartmoorDartmoor is an area of moorland in the centre of Devon, England. Protected by National Park status, it covers .The granite upland dates from the Carboniferous period of geological history. The moorland is capped with many exposed granite hilltops , providing habitats for Dartmoor wildlife. The...
and
Bodmin MoorBodmin Moor is a granite moorland in northeastern Cornwall, UK, in size, dating from the Carboniferous period of geological history.The name "Bodmin Moor" is relatively recent, being an Ordnance Survey invention of 1813...
, giving rise to mineralised deposits of
copperCopper is a chemical element with the symbol Cu and atomic number 29.It is a ductile metal with very high thermal and electrical conductivity. Pure copper is rather soft and malleable and a freshly-exposed surface has a pinkish or peachy color...
and
tinTin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead, like the two possible oxidation states +2 and +4...
. The general region of Variscan folding was south of an east–west line roughly from south
PembrokeshirePembrokeshire is a county in the southwest of Wales.-Geography:Pembrokeshire is a maritime county, bordered by the sea on three sides, by Ceredigion to the north east and by Carmarthenshire to the east...
to
KentKent , originally Cantia, is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the River Thames estuary. The ceremonial county boundaries of Kent include the shire county of Kent...
. The main tectonic pressure was from the south or south-east, and may have resulted in dextral strike-slip faulting. The
DevonDevon is a large county in England. The county is also referred to as Devonshire, although that is an unofficial name, rarely used inside of the county itself and often indicating a traditional or historical context. The county shares borders with Cornwall to the west and Dorset and Somerset to...
-
CornwallCornwall is a county of England in the United Kingdom, forming the tip of the south-western peninsula of Great Britain. It is bordered to the north and west by the Atlantic Ocean, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Taken with the...
massif may originally have been some distance further east, then to be moved westwards. Lesser Variscan folding took place as far north as
DerbyshireDerbyshire is a county in the East Midlands of England. A substantial portion of the Peak District National Park lies within Derbyshire. The northern part of Derbyshire overlaps with the Pennines, a famous chain of hills and mountains...
and
Berwick-upon-TweedBerwick-upon-Tweed or simply Berwick, is a town in the county of Northumberland and is the northernmost town in England, on the east coast at the mouth of the River Tweed. It is situated 2.5 miles south of the Scottish border....
.
By the end of the period the various continents of the World had fused to form one super-continent of
PangaeaPangaea, Pangæa, or Pangea was the supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration.The name was first used by the German originator of the continental...
, with
BritainGreat Britain is an island lying to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island. With a population of about 59.6 million people, it is the third most populated island on Earth. Great Britain is surrounded by over 1000 smaller...
in the interior, where it was again subject to a hot arid desert climate, with frequent flash floods leaving deposits that formed red beds, somewhat similar to the later,
TriassicThe Triassic is a geologic period and system that extends from about 251 to 199 Ma . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
New Red SandstoneThe New Red Sandstone is a chiefly British geological term for the beds of red sandstone and associated rocks laid down throughout the Permian to the beginning of the Triassic that underlie the Jurassic Lias; the term distinguishes it from the Devonian Old Red Sandstone...
.
Permian period
The
PermianThe Permian
[The term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named...]
was characterised for 30 million years by arid desert and erosion of the areas uplifted in the Variscan Orogeny (southwest England and adjacent areas in the present-day English Channel). Later, much of Great Britain was submerged in shallow waters as the polar ice sheets melted and the
Tethys OceanThe Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean.-Modern theory:...
and Zechstein Sea formed, depositing
shaleShale is a fine-grained, clastic sedimentary rock composed of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable...
,
limestoneLimestone is a sedimentary rock composed largely of the mineral calcite . The deposition of limestone strata is often a by-product and indicator of biological activity in the geologic record...
,
gravelGravel is rock that is of a specific particle size range. Specifically, it is any loose rock that is larger than two millimeters in its smallest dimension and no more than . The next smaller size class in geology is sand, which is > in size. The next larger size is cobble, which is >. Gravel can...
, and
marlMarl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and aragonite. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay...
, before finally receding to leave a flat desert with
salt panSalt pans can refer to:*Salt pan , a flat expanse of ground covered with salt and other minerals, usually found in deserts*Salt evaporation pond, a method of producing salt by evaporating brine...
s.
Triassic period
As Pangaea drifted during the
TriassicThe Triassic is a geologic period and system that extends from about 251 to 199 Ma . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
, Great Britain moved away from the equator until it was between 20° and 30° north. Red beds, including sandstones and red
mudstoneMudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...
s form the main sediments of the
New Red SandstoneThe New Red Sandstone is a chiefly British geological term for the beds of red sandstone and associated rocks laid down throughout the Permian to the beginning of the Triassic that underlie the Jurassic Lias; the term distinguishes it from the Devonian Old Red Sandstone...
. The remnants of the Variscan uplands in
FranceFrance , officially the French Republic , is a country located in Western Europe, with several overseas islands and territories located on other continents. Metropolitan France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean...
to the south were eroded down, resulting in layers of the New Red Sandstone being deposited across central England, and in
faultedIn geology, a fault or fault line is a planar fracture in rock in which the rock on one side of the fracture has moved with respect to the rock on the other side. Large faults within the Earth's crust are the result of differential or shear motion and active fault zones are the causal locations of...
basins in
CheshireCheshire ; also known, archaically, as the County of Chester) is a ceremonial county in North West England. The traditional county town is the city of Chester, although Cheshire's largest town is Warrington. Other major towns include Congleton, Crewe, Ellesmere Port, Widnes, Runcorn, Macclesfield,...
and the Irish Sea. A basin developed in the
HampshireHampshire , sometimes historically Southamptonshire, Hamptonshire, , or the County of Southampton, is a county on the south coast of England. The county borders , Dorset, Wiltshire, Berkshire, Surrey and West Sussex...
region around this time.
RiftIn geology, a rift is a place where the Earth's crust and lithosphere are being pulled apart and is an example of extensional tectonics....
ing occurred within and around Britain and Ireland, prior to the breakup of the super-continent in the
JurassicThe Jurassic is a geologic period and system that extends from about Ma to Ma, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the "Age of Reptiles". The start of the period is marked by...
period.
Rock fragments found near
BristolBristol is a city, unitary authority area and ceremonial county in South West England, west of London, and east of Cardiff.With an estimated population of 416,400 for the unitary authority in mid-2007, and a surrounding urban area with an estimated 561,500 residents, it is England's sixth, and...
appear to indicate that in 214 Ma Great Britain was showered with a fine layer of debris from an
asteroid impactAn impact event is the collision of a large meteorite, asteroid, comet, or other celestial object with the Earth or another planet. Impact events have been a plot and background element in science fiction since knowledge of real impacts became established in the scientific mainstream.-Sizes and...
at the Manicouagan Impact Crater in
CanadaCanada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean...
, although this is still being debated.
Jurassic period
As the
JurassicThe Jurassic is a geologic period and system that extends from about Ma to Ma, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the "Age of Reptiles". The start of the period is marked by...
started,
PangaeaPangaea, Pangæa, or Pangea was the supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration.The name was first used by the German originator of the continental...
began to break up and sea levels rose, as Britain and Ireland drifted on the
Eurasian PlateThe Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia , with the notable exceptions of the Indian subcontinent, the Arabian subcontinent, and the area east of the Chersky Range in East Siberia...
to between 30° and 40° north. With much of the Isles under water again,
sedimentary rockSedimentary rock is the type of rock that is formed by sedimentation of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
s were deposited and can now be found underlying much of southern England from the
Cleveland HillsThe Cleveland Hills are a range of hills on the northern edge of the North York Moors in North Yorkshire, England, overlooking Cleveland and Teesside....
of
YorkshireYorkshire is a historic county of northern England and the largest in the British Isles. Because of its great size, functions were increasingly undertaken over time by its subdivisions, which have been subject to periodic reform. Throughout these changes, Yorkshire has continued to be recognised as...
to the
Jurassic CoastThe Jurassic Coast is a World Heritage Site on the English Channel coast of southern England. The site stretches from Orcombe Point near Exmouth in East Devon to Old Harry Rocks near Swanage in East Dorset, a distance of ....
in
DorsetDorset, England, rests on a variety of different rock types which give the county its interesting landscapes and habitats. Dorset is particularly noted for its coastline, the Jurassic Coast, which in 2001 was designated a World Heritage Site because of the variety of landforms and fossils...
, including
clayClay is a naturally occurring material composed primarily of fine-grained minerals, which show plasticity through a variable range of water content, and which can be hardened when dried and/or fired...
s,
sandstoneSandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow,...
s,
greensandGreensand is an olive-green coloured sandstone rock which is commonly found in narrow bands, particularly associated with bands of chalk and clay worldwide; it has been deposited in marine environments at various times during Earth history, such as during the Jurassic and Cretaceous...
s,
ooliticOolite is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Hellenic word òoion for egg. Strictly, oolites consist of ooids of diameter 0.25–2 mm: rocks composed of ooids larger than 2 mm are called pisolites...
limestoneLimestone is a sedimentary rock composed largely of the mineral calcite . The deposition of limestone strata is often a by-product and indicator of biological activity in the geologic record...
of the Cotswold Hills,
corallian limestoneCorallian Limestone is a coralliferous sedimentary rock, laid down in Jurassic times. It is a hard variety of "coral rag". Building stones from this geological structure tend to be irregular in shape. It is often found close to seams of Portland Limestone...
of the
Vale of White HorseThe Vale of White Horse is a local government district of Oxfordshire in England. The main town is Abingdon, other places include Faringdon and Wantage. There are 68 parishes within the district....
and the Isle of Portland.
The burial of
algaeAlgae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in...
and bacteria below the mud of the sea floor during this time resulted in the formation of
North Sea oilNorth Sea oil is a mixture of hydrocarbons, comprising liquid oil and natural gas, produced from oil reservoirs beneath the North Sea. In the oil industry, the term "North Sea" often includes areas such as the Norwegian Sea and the UK "Atlantic Margin" that are not, strictly speaking, part of the...
and
natural gasNatural gas is a gas consisting primarily of methane. It is found associated with fossil fuels, in coal beds, as methane clathrates, and is created by methanogenic organisms in marshes, bogs, and landfills...
, much of it trapped in overlying sandstone by
saltA salt, in chemistry, is an ionic compound, and can result from the neutralization reaction of acids and bases. Salts are ionic compounds composed of cations and anions so that the product is electrically neutral...
deposits formed as the seas fell to form the swamps and salty lakes and lagoons that were home to
dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
s. {{Fact|date=August 2008}}
Cretaceous period
The modern continents having formed, the
CretaceousThe Cretaceous , Latin language for "chalky", usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago . In the geologic timescale, the Cretaceous follows on the Jurassic period and is followed by the Paleogene period of the...
saw the formation of the
Atlantic OceanThe Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about 106.4 million square kilometres , it covers approximately one-fifth of the Earth's surface and about one-quarter of its water surface area. The first part of its name refers to the Atlas of Greek...
, gradually separating northern Scotland from
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
. The land underwent a series of uplifts to form a fertile plain.
After 20 million years or so, the seas started to flood the land again until much of Britain and Ireland were again below the sea, though sea levels frequently changed.
ChalkChalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. It forms under relatively deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores. It is common to find flint and chert...
and
flintFlint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in color, and...
s were deposited over much of Great Britain, now notably exposed at the
White Cliffs of DoverThe white cliffs of Dover are cliffs which form part of the British coastline facing the Strait of Dover and France. The cliffs are part of the North Downs formation. The cliff face, which reaches up to 348ft high, owes its striking façade to its composition of chalk accentuated by streaks of...
and the
Seven SistersThe Seven sisters are a series ofchalk cliffs by the English Channel. They form part of the South Downs in East Sussex, between the towns of Seaford and Eastbourne in southern England. They are within the Seven Sisters Country Park...
, and also forming
Salisbury PlainSalisbury Plain is a chalk plateau in central southern England covering . It is part of the Southern England Chalk Formation and largely lies within the county of Wiltshire, with a little in Hampshire. The plain is famous for its rich archaeology, including Stonehenge, one of England's best known...
. The high sea levels left only small areas of land exposed. This caused the general lack of land-origin sand, mud or clay sediments around this time - some of the late Cretaceous strata are almost pure chalk.
Palaeogene period
In the early Palaeogene period between 63 and 52 Ma, the last volcanic rocks in Great Britain were formed, with the major eruptions that formed the
Antrim PlateauCounty Antrim is one of the traditional counties of Ireland. It is located within the province of Ulster and is part of Northern Ireland. It was named after the town of Antrim ....
and the
basaltBasalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey.On Earth, most...
ic columns of the
Giant's CausewayThe Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is located in County Antrim, on the northeast coast of Northern Ireland, about two miles north of the town of Bushmills...
. The volcanic Lundy Island in the
Bristol ChannelThe Bristol Channel is a major inlet in the island of Great Britain, separating South Wales from Devon and Somerset in South West England, and extending from the lower estuary of the River Severn to the North Atlantic Ocean...
also dates from this period.
The
Alpine OrogenyThe Alpine orogeny is an orogenic phase in the Late Mesozoic and Tertiary that formed the mountain ranges of the Alpide belt...
that took place about 50 Ma was responsible for the shaping of the
London BasinThe London Basin is an elongated, roughly triangular sedimentary basin approximately long which underlies London and a large area of south east England, south eastern East Anglia and the adjacent North Sea...
synclineIn structural geology, a syncline is a downward-curving fold, with layers that dip toward the center of the structure. A synclinorium is a large syncline with superimposed smaller folds....
, the
Weald-Artois AnticlineThe Weald–Artois anticline is a large anticline, a geological structure running between the regions of the Weald in southern England and the Artois in northeastern France. The fold formed during the Alpine orogeny, from the late Oligocene to middle Miocene...
to the south, and also the North Downs, South Downs and Chiltern Hills.
During the period the
North SeaThe North Sea is a marginal, epeiric sea on the European continental shelf. The Dover Strait and the English Channel in the south and the Norwegian Sea in the north connect it to the Atlantic Ocean. It is more than long and wide, with an area of around...
formed, Britain was
upliftUplift may refer to:* Biological uplift, the theoretical prospect of upgrading the capacities of a species or a civilization.** Uplift Universe, the setting for a series of novels by David Brin in which Biological Uplift is a central aspect...
ed. Some of this uplift was along old lines of weakness from the Caledonian and Variscan Orogenies long before. The uplifted areas were then eroded, and further sediments were deposited over southern England, including the
London ClayThe London Clay Formation is a marine geological formation of Ypresian age which crops out in the southeast of England. The London Clay is well known for the fossils it contains. The fossils from the Lower Eocene indicate a moderately warm climate, the flora being tropical or subtropical...
, while the
English ChannelThe English Channel is an arm of the Atlantic Ocean that separates England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest, to only in the Strait of Dover...
consisted of mud flats and river deposited
sandSand is a naturally occurring granular material composed of finely divided rock and mineral particles.As the term is used by geologists, sand particles range in diameter from 0.0625 to 2 millimeters. An individual particle in this range size is termed a sand grain...
s. Much of the midlands and north of England may have been covered by Jurassic and Cretaceous deposits at the start of the Palaeogene, but lost them through erosion. By 35 Ma the landscape included
beechBeech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.The leaves of beech trees are entire or sparsely toothed, from 5–15 cm long and 4–10 cm broad...
,
oakAn oak is a tree or shrub in the genus Quercus , of which about 400 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
,
redwoodSequoia sempervirens is the sole living species of the genus Sequoia in the cypress family Cupressaceae . Common names include Coast Redwood and California Redwood...
and
palmArecaceae or Palmae , the palm family, is a family of flowering plants, the only family in the monocot order Arecales...
trees, along with
grassGrasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns...
land.
Miocene and Pliocene epochs
In the
MioceneThe Miocene is a geological epoch of the Neogene period and extends from about 23.03 to 5.33 million years before the present . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the...
and
PlioceneThe Pliocene epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present....
epochs of the
NeogeneThe Neogene is a geologic period and system starting 23.03 ± 0.05 million years ago and lasting either until today or ending 2.588 million years ago with the beginning of the Quaternary. The Neogene Period follows the Paleogene Period of the Cenozoic Era...
, further uplift and erosion occurred, particularly in Wales, the Pennines, and the Scottish Highlands. Plant and animal types developed into their modern forms, and by about 2 million years ago the landscape would have been broadly recognisable today.
Pleistocene epoch
The major changes during the
PleistoceneThe Pleistocene is the epoch from 2.588 million to 12 000 years BP covering the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
have been brought about by several recent
ice ageThe general term "ice age" or, more precisely, "glacial age" denotes a geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in an expansion of continental ice sheets, polar ice sheets and alpine glaciers. Within a long-term ice age, individual...
s.
The most severe was the Anglian Stage, with ice up to 1,000 m (3300 ft) thick that reached as far south as
London[]London is the capital of England and the United Kingdom. It has been a major settlement for two millennia, and the history of London goes back to its founding by the Romans, when it was named Londinium. London's core, the ancient City of London, the 'square mile', retains its medieval boundaries...
and
BristolBristol is a city, unitary authority area and ceremonial county in South West England, west of London, and east of Cardiff.With an estimated population of 416,400 for the unitary authority in mid-2007, and a surrounding urban area with an estimated 561,500 residents, it is England's sixth, and...
, took place between about 478,000 to 424,000 years ago, and was responsible for the diversion of the
River ThamesThe River Thames is a major river flowing through southern England. While best known because its lower reaches flow through central London, the river flows through several other towns and cities, including Oxford, Reading and Windsor....
onto its present course.
There is extensive evidence in the form of stone tools that southern England was colonised by
humanHumans are bipedal primates belonging to the species Homo sapiens in Hominidae, the great ape family. They are the only surviving member of the genus Homo. Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving...
populations during the warm Hoxnian Stage that followed the Anglian Glaciation. It is possible that the
English ChannelThe English Channel is an arm of the Atlantic Ocean that separates England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest, to only in the Strait of Dover...
repeatedly opened and closed during this period, causing Britain to become an island from time to time. The oldest human
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
s in the Isles also date from this time, including the skull of Swanscombe Man from 250,000 years ago, and the earlier Clactonian Man.
The Wolstonian Stage, between about 352,000 to 130,000 years ago, and thought to have peaked around 150,000 years ago, was named after the town of
WolstonWolston is a village and civil parish in the Rugby borough of Warwickshire, England. The village is located roughly halfway between Rugby and Coventry, and has a population of about 2,300....
south of
BirminghamBirmingham is a city and metropolitan borough in the West Midlands county of England. Birmingham is the second-most populous British city, with a population of 1,006,500 ....
which is thought to mark the southern limit of the ice.
The Wolstonian Stage was followed by the Ipswichian Stage, during which
hippopotamusThe hippopotamus or hippo is a large, mostly plant-eating mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae...
are known to have lived as far north as
LeedsLeeds is a city and metropolitan borough in West Yorkshire, England. The historic core at the heart of Leeds in 2001 had an estimated subdivision population of 443,247, whilst the entire city, that includes the urban and suburban areas incorporated into the city in 1974, had an estimated...
.
During the most recent Devensian glaciation, which is thought to have started around 115,000 years ago, peaked around 20,000 years ago and ended a mere 10,000 years ago, the
Usk valleyThe River Usk rises in the Carmarthen Fans mountains or Fan Brycheiniog of mid-Wales, in the westernmost part of the Brecon Beacons National Park then flows south-east through Brecon , Crickhowell, Abergavenny and the eponymous town of Usk past the Roman legionary fortress of Caerleon, through...
and
Wye valleyThe River Wye is the fifth-longest river in the UK and for parts of its length forms part of the border between England and Wales. It is important for nature conservation and recreation.-Description:...
were eroded by
glacierA glacier is a perennial mass of ice which moves over land. A glacier forms in locations where the mass accumulation of snow and ice exceeds ablation over many years...
s, with the ice sheet itself reaching south to
BirminghamBirmingham is a city and metropolitan borough in the West Midlands county of England. Birmingham is the second-most populous British city, with a population of 1,006,500 ....
. The oldest human remains in Britain or Ireland, the
Red Lady of PavilandThe Red Lady of Paviland is a fairly complete Upper Paleolithic-era human male skeleton dyed in red ochre, discovered in 1823 by Rev. William Buckland in one of the Paviland limestone caves of the Gower peninsula in south Wales, dating from c29,000 BP....
(29,000 years old) date from this time. It is thought that the country was eventually abandoned as the ice sheet reached its peak, being recolonised as it retreated. By 5,000 years ago it is thought that Great Britain was warmer than it is at present.
Among the features left behind by the ice are the
fjordGeologically, a fjord is a long, narrow inlet with steep sides, created in a valley carved by glacial activity.-Formation:Fjords are formed when a glacier cuts a v-shaped valley by abrasion of the surrounding bedrock. Many such valleys were formed during the recent ice age...
s of the west coast of Scotland, the U shaped valleys of the
Lake DistrictThe Lake District, also known as The Lakes or Lakeland, is a rural area in North West England. A popular holiday destination, it is famous for its lakes and its mountains , and its associations with the early 19th century poetry and writings of William Wordsworth and the Lake Poets.The central and...
and
erraticErratic can refer to:* Erratic, a side project of experimental electronic artist Jan Robbe* glacial erratic* erratic ant...
s (blocks of rock) that have been transported from the
Oslois the capital and largest city in Norway. Founded around 1048 by King Harald III of Norway, the town was largely destroyed by a fire in 1624. The Danish–Norwegian king Christian IV rebuilt the city as Christiania . Oslo, then an alternative name, became official again in 1925...
region of
NorwayNorway , officially the Kingdom of Norway, is a country in Northern Europe occupying the western portion of the Scandinavian Peninsula, as well as Jan Mayen and the Arctic archipelago of Svalbard under the Spitsbergen Treaty...
and deposited on the coast of
YorkshireYorkshire is a historic county of northern England and the largest in the British Isles. Because of its great size, functions were increasingly undertaken over time by its subdivisions, which have been subject to periodic reform. Throughout these changes, Yorkshire has continued to be recognised as...
.
Holocene epoch
Over the last twelve thousand years (the
HoloceneThe Holocene is a geological epoch which began approximately 11 700 years ago . According to traditional geological thinking, the Holocene continues to the present. The Holocene is part of the Neogene and Quaternary periods. Its name comes from the Greek words and , meaning "entirely...
Epoch) the most significant new geological features have been the deposits of
peatPeat is an accumulation of partially decayed vegetation matter. Peat forms in wetlandbogs, moors, muskegs, pocosins, mires, and peat swamp forests...
in Ireland and Scotland, as well as in coastal areas that have recently been artificially drained such as the
Somerset LevelsThe Somerset Levels is a sparsely populated coastal plain and wetland area of central Somerset, England, between the Quantock and Mendip hills....
,
The FensThe Fens, also known as the Fenland, is a geographic area in eastern England, in the United Kingdom.The Fenland primarily lies around the coast of the Wash; it reaches into two Government regions , four ceremonial counties , 11 District Councils and six postcode areas The Fens, also known as the...
and
Romney MarshThe Romney Marsh is a sparsely populated wetland area in the counties of Kent and East Sussex in the south-east of England. It covers about 100 square miles .-Quotations:*“As Egypt was the gift of the Nile, this level tract .....
in England.
Since humans began clearing the forest during the
new stone ageThe Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BCE in the Middle East that is traditionally considered the last part of the Stone Age...
, most of the land has now been deforested, speeding the natural processes of
erosionErosion is a gravity driven process that moves solids in the natural environment or their source and deposits them elsewhere...
. Large quantities of stone, gravel and clay are extracted each year, and by 2000 11% of England was covered by
roadA road is an identifiable route, way or path between places.
s or
buildingIn architecture, construction, engineering and real estate development the word building may refer to one of the following:# Any man-made structure used or intended for supporting or sheltering any use or continuous occupancy, or...
s.
At the present time Scotland is continuing to rise as a result of the weight of Devensian ice being lifted. The rest of Britain is sinking, generally estimated at 1 mm (1/25 inch) per year, with the London area sinking at double the speed partly due to the continuing
compactionCompaction refers to the process by which a sediment progressively loses its porosity due to the effects of loading. This forms part of the process of lithification. When a layer of sediment is originally deposited, it contains an open framework of particles with the pore space being usually...
of the recent clay deposits.
In addition, rises in sea level thought to be due to
global warmingGlobal warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C during the last century...
appear likely to make low lying areas of land increasingly susceptible to flooding, while in some areas the coastline continues to erode at a geologically rapid rate.
Great Britain continues to be subject to several very minor
earthquakeAn earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are recorded with a seismometer, also known as a seismograph...
s each month, and occasional light to moderate ones. During the 20th century 25 earthquakes with a moment magnitude of 4.5 to 6.1 were felt
http://www.quakes.bgs.ac.uk/hazard/eqlst.htm, many of them originating within the Isles themselves.
Geological features
- Cheddar Gorge - the largest gorge in Great Britain
- Jurassic Coast
The Jurassic Coast is a World Heritage Site on the English Channel coast of southern England. The site stretches from Orcombe Point near Exmouth in East Devon to Old Harry Rocks near Swanage in East Dorset, a distance of ....
- a UNESCOThe United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations established on 16 November 1945...
World Heritage SiteA UNESCO World Heritage Site is a site that is on the list that is maintained by the international World Heritage Programme administered by the UNESCO World Heritage Committee, composed of 21 state parties which are elected by their General Assembly for a four-year term.A World Heritage Site is a...
- Great Glen Fault
The Great Glen Fault is a long strike-slip fault that runs through its namesake the Great Glen in Scotland. However, the fault is actually much longer and over 400 million years old.-Location:...
- Highland Boundary Fault
The Highland Boundary Fault is a geologic fault that traverses Scotland from Arran and Helensburgh on the west coast to Stonehaven in the east. It separates two distinctly different physiographic regions: the Highlands from the Lowlands, but in most places it is only recognisable as a change in...
- Southern Uplands Fault
- Midland Valley of Scotland
The Central Lowlands or Midland Valley is a geologically defined area of relatively low-lying land in southern Scotland. It consists of a rift valley between the Highland Boundary Fault to the north and the Southern Uplands Fault to the south...
- Fingal's Cave
Fingal's Cave is a sea cave on the uninhabited island of Staffa, in the Inner Hebrides of Scotland, part of a National Nature Reserve owned by the National Trust for Scotland. It is formed entirely from hexagonally-jointed basalt columns, similar in structure to the Giant's Causeway in Northern...
- columnar Tertiary basaltic formation (similar to the Giant's CausewayThe Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is located in County Antrim, on the northeast coast of Northern Ireland, about two miles north of the town of Bushmills...
in Northern IrelandNorthern Ireland is a part of the United Kingdom of Great Britain and Northern Ireland and it is situated in the north-east of the island of Ireland. It shares a border with the Republic of Ireland to the south and west...
)
- Salisbury Plain
Salisbury Plain is a chalk plateau in central southern England covering . It is part of the Southern England Chalk Formation and largely lies within the county of Wiltshire, with a little in Hampshire. The plain is famous for its rich archaeology, including Stonehenge, one of England's best known...
- Tees-Exe line
The Tees-Exe line is an imaginary line that can be drawn on a map of Great Britain which roughly divides the lowland and upland regions of the country....
- Whin Sill
The Whin Sill is a tabular layer of igneous rock, or sill, in County Durham and Northumberland, in the northeast of England. It lies partly in the North Pennines Area of Outstanding Natural Beauty and partly in Northumberland National Park...
- Siccar Point
Siccar Point is a rocky promontory in the county of Berwickshire on the east coast of Scotland.It is famous in the history of geology for Hutton's Unconformity found in 1788, which James Hutton regarded as conclusive proof of his uniformitarian theory of geological development.-History:Siccar...
in BerwickshireBerwickshire or the County of Berwick, is a registration county, a committee area of the Scottish Borders Council, and a lieutenancy area of Scotland, on the border with England. The town after which it is named—Berwick-upon-Tweed—was lost by Scotland to England in 1482...
provided early proof of the immense age of the Earth.
- The Moine Thrust
The Moine Thrust Belt is a linear geological feature in the Scottish Highlands which runs from Loch Eriboll on the north coast 190 km south-west to the Sleat peninsula on the Isle of Skye...
was the first thrust belt to be discovered by geologists.
- London Basin
The London Basin is an elongated, roughly triangular sedimentary basin approximately long which underlies London and a large area of south east England, south eastern East Anglia and the adjacent North Sea...
- Hampshire Basin
The Hampshire Basin is a geological syncline in southern England underlying parts of Hampshire, the Isle of Wight, Dorset, and Sussex. Like the London Basin to the northeast, it consists of an area of sands and clays of Paleocene and younger age surrounded by a broken rim of chalk hills of...
- London-Brabant Massif
- Dartmoor
Dartmoor is an area of moorland in the centre of Devon, England. Protected by National Park status, it covers .The granite upland dates from the Carboniferous period of geological history. The moorland is capped with many exposed granite hilltops , providing habitats for Dartmoor wildlife. The...
- one of a series of Moors in the South West of England developing Tors on a graniticGranite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite has a medium to coarse texture, occasionally with some individual crystals larger than the groundmass forming a rock known as porphyry. Granites can be pink to dark gray or even black, depending on their...
batholithA batholith is a large emplacement of igneous intrusive rock that forms from cooled magma deep in the earth's crust...
- Lizard Complex - an ancient piece of oceanic crust
Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima...
, onshore (i.e. an Ophiolite).
Geological resources
- Coal
Coal is a readily combustible black or brownish-black sedimentary rock normally occurring in rock strata in layers or veins called coal beds. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
- North Sea oil
North Sea oil is a mixture of hydrocarbons, comprising liquid oil and natural gas, produced from oil reservoirs beneath the North Sea. In the oil industry, the term "North Sea" often includes areas such as the Norwegian Sea and the UK "Atlantic Margin" that are not, strictly speaking, part of the...
- Sand and Gravel
- China Clay
- Copper and Tin
Mining in Cornwall first began in the early Bronze Age approximately 2,150 BC and ended with the South Crofty tin mine closing in 1998.-History:...
- Stone
and less abundantly,
- Geothermal energy
- Onshore oil
Events
- Storegga Slide
The three Storegga Slides are considered to be amongst the largest known landslides. They occurred under water, at the edge of Norway's continental shelf , in the Norwegian Sea, 100 km north-west of the Møre coast. An area the size of Iceland slumped, causing a very large tsunami in the North...
s, caused a tsunami circa 6100 BC
- Bristol Channel floods, 1607
On 30 January, 1607 the Bristol Channel floods resulted in the drowning of an estimated 2,000 or more people, with houses and villages swept away, an estimated of farmland inundated and livestock destroyed, wrecking the local economy along the coasts of the Bristol Channel, UK.The...
was caused by a tsunami
- 1755 Lisbon earthquake
The 1755 Lisbon earthquake, also known as the Great Lisbon Earthquake, took place on 1 November 1755, at around 9:40 in the morning. The earthquake was followed by a tsunami and fires, which caused near-total destruction of Lisbon in the Kingdom of Portugal, and adjoining areas...
caused a tsunami that hit CornwallCornwall is a county of England in the United Kingdom, forming the tip of the south-western peninsula of Great Britain. It is bordered to the north and west by the Atlantic Ocean, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Taken with the...
.
- Colchester earthquake
The earthquake known as the Colchester Earthquake occurred on April 22 1884, and caused considerable damage in Colchester and the surrounding villages in Essex, England. It is also known as the Great English Earthquake...
, 1884
- 2002 Dudley earthquake
The 2002 Dudley earthquake was an earthquake registering 4.7 on the Richter scale that struck the Midlands of England, on 22 September 2002 23:54 UTC and lasted approximately 20 seconds....
- 2008 Lincolnshire earthquake
The 2008 Lincolnshire earthquake struck Lincolnshire, in the United Kingdom, on 27 February 2008 at 00:56:47.8s GMT. According to the British Geological Survey, the quake registered a reading of 5.2 on the Richter scale with the epicentre 2.5 miles north of Market Rasen and 15 miles south-west of...
Learned societies
- Geological Society of London
The Geological Society of London is a learned society based in the United Kingdom with the aim of "investigating the mineral structure of the Earth". It is the oldest national geological society in the world and the largest in Europe with over 9000 Fellows entitled to the postnominal FGS - over...
- Edinburgh Geological Society
The Edinburgh Geological Society was founded in 1834 in Edinburgh, Scotland, with the aim of stimulating public interest in geology and the advancement of geological knowledge...
- Royal Geological Society of Cornwall
The Royal Geological Society of Cornwall is a geological society based in Cornwall in the United Kingdom. It was founded in 1814 to promote the study of the geology of Cornwall, and is the second oldest geological society in the world....
Pioneers of British Geology
- Mary Anning
Mary Anning was an early British fossil collector and paleontologist.-Early life:Born in the coastal southern English town of Lyme Regis in Dorset, Mary Anning was marked out for an unusual life at the age of 15 months when in 1800 a lightning strike in the village caught four people in the open...
1799-1847
- Thomas George Bonney
Thomas George Bonney FRS was an English geologist.Bonney was the eldest son of the Reverend Thomas Bonney, master of Rugeley Grammar School...
1833-1923
- William Buckland
The Very Rev. Dr William Buckland DD FRS was an English geologist, palaeontologist and Dean of Westminster, who wrote the first full account of a fossil dinosaur...
1784-1856
- William Conybeare 1787-1857
- James Hutton
James Hutton MD was a Scottish geologist, physician, naturalist, chemist and experimental farmer. He is considered the father of modern geology...
1726-1797 the "Father of modern geology"
- Charles Lapworth
Charles Lapworth was an English geologist.Born at Faringdon in Berkshire , and trained as a teacher, Lapworth settled in the Scottish border region, where he investigated the previously little-known fossil fauna of the area. He married during 1869 and stayed in the area...
1842–1920
- Sir Charles Lyell
Sir Charles Lyell, 1st Baronet, Kt, FRS was a British lawyer, geologist, and proponent of uniformitarianism. He was the foremost geologist of his day, and an influence on the young Charles Darwin.- Life :...
1797-1875
- Gideon Mantell
Gideon Algernon Mantell MRCS FRS was an English obstetrician, geologist and palaeontologist...
1790-1852
- Sir Roderick Murchison
Sir Roderick Impey Murchison, 1st Baronet KCB FRS was a British geologist who first described and investigated the Silurian system.- Early life and work :...
1792–1871
- John Phillips
John Phillips FRS was an English geologist.- Life and work :Philips was born at Marden in Wiltshire...
1800–1874
- Adam Sedgwick
Adam Sedgwick was one of the founders of modern geology. He proposed the Devonian period of the geological timescale and later the Cambrian period. The latter proposal was based on work which he did on Welsh rock strata...
1785-1873
- William Smith
William Smith was an English geologist, credited with creating the first nationwide geological map. He is known as the "Father of English Geology", although recognition was very slow in coming...
1769-1839 the "Father of English geology"
Awards
- Wollaston Medal
The Wollaston Medal is a scientific award for geology, the highest award granted by the Geological Society of London.The medal is named after William Hyde Wollaston, and was first awarded in 1831...
See also
- Geologic timescale
- Chalk Formation
The Chalk Group is a lithostratigraphic unit in the northwestern part of Europe. It is characterised by thick deposits of chalk, a soft porous white limestone, deposited in a marine environment during the Upper Cretaceous period.Chalk is a limestone that consists of coccolith biomicrite...
- Gault Clay
The Gault Clay is a formation of stiff blue clay deposited in a calm, fairly deep water marine environment during the Lower Cretaceous Period...
External links
{{Geology of Europe}}
{{British Geology}}
{{United Kingdom topics}}