Irish Sea 144225 226104241 2008-07-16T21:01:50Z Chris55 1033358 /* Shipping */ [[Image:IrishSeaReliefMap.jpg|thumb|320px|right|Relief map of the Irish Sea. [[Freight]] and passenger [[port]]s shown as red dots. Freightonly ports as blue dots]] {{wiktionary}} The '''Irish Sea''' ([[Irish language|Irish]]: '''Muir Éireann''' or '''Muir Meann'''; [[Scottish Gaelic]]: '''Muir Eireann''' [[Welsh language|Welsh]]: '''Môr Iwerddon''', [[Manx language|Manx]]: '''Mooir Vannin''') separates the [[Island|islands]] of [[Ireland]] and [[Great Britain]]. It is connected to the [[Celtic Sea]] portion of the [[Atlantic Ocean]] by [[St George's Channel]] between [[Republic of Ireland|Ireland]] and [[Wales]], and to the north by the [[North Channel (Britain and Ireland)|North Channel]] between [[Northern Ireland]] and [[Scotland]] which forms part of the [[International Hydrographic Organisation]] designated [[Inner Seas off the West Coast of Scotland]] marine area. The [[Isle of Man]] lies in the middle of the Irish Sea. The sea is of significant economic importance to regional [[trade]], [[shipping]] and [[transport]], [[fishing]] and [[power generation]] in the form of [[wind power]] and [[nuclear plant]]s. There has been long discussion of building an 80&nbsp;[[km]] (50 [[mile]]) [[rail tunnel]] to link Britain and Ireland. Annual traffic between the two islands amounts to over 12 million passengers and 17 million [[tonne|tonnes]] of trade. ==Shipping== Unlike Britain, Ireland has no tunnel or [[bridge]] connection to mainland [[Europe]]. Thus the vast majority of heavy goods trade is done by [[sea]]. Northern Irish [[Port|ports]] handle 10 million tonnes of goods trade with Britain annually, while ports in the Republic handle 7.6 million tonnes, representing 50% and 40% respectively of total trade by [[weight]]. The [[Port of Liverpool]] handles 32 million tonnes of [[cargo]] and 734 thousand passengers a year.<ref>Port Statistics, [http://www.merseydocks.co.uk/index2.htm (Link)], Mersey Docks Website</ref> [[Holyhead]] port handles most of the passenger traffic from [[Dublin port|Dublin]] and [[Dún Laoghaire]] ports, as well as 3.3 million tonnes of freight.<ref>UK Port Traffic Highlights: 2002, [http://www.maritimestatistics.org/pdfs/port%20traffic%20highlights%202002.pdf (pdf)], UK Maritime Statistics, Dept of Transport</ref> Ports in the Republic handle 3,600,000 travellers crossing the Irish Sea each year, amounting to 92% of all sea travel.<ref> Direct Passenger Movement by Sea from and to Ireland (Republic), [http://www.cso.ie/statistics/passengermovementbysea.htm (link)], [[Central Statistics Office of Ireland]]</ref> This has been steadily dropping for a number of years (20% since 1999), probably as a result of low cost airlines.{{Fact|date=March 2008}} [[Ferry]] connections from Britain to Ireland across the Irish Sea include the routes from [[Swansea]] to [[Cork (city)|Cork]]; [[Fishguard]] and [[Pembroke, Wales|Pembroke]] to [[Rosslare]]; Holyhead to Dún Laoghaire; Holyhead to Dublin; [[Stranraer]] to [[Belfast]] and [[Larne]]; and [[Cairnryan]] to Larne. There is also a connection between [[Liverpool]] and Belfast via the [[Isle of Man]] or direct from [[Birkenhead]]. The world's largest [[car ferry]], ''[[Ulysses (ship)|Ulysses]]'', is operated by [[Irish Ferries]] on the Dublin Port&ndash;Holyhead route, [[Stena Line]] also operates between Britain and Ireland. [[Barrow-in-Furness]] despite being one of Britain's largest [[shipbuilding]] centres, and being home to the [[United Kingdom]]'s only [[submarine]]-building complex, is only a minor port. "Irish Sea" is also the name of one of the [[BBC]]'s [[Shipping Forecast]] areas defined by the coordinates: {{coord|54|50|N|05|05|W}} {{coord|54|45|N|05|45|W}} {{coord|52|30|N|06|15|W}} {{coord|52|00|N|05|05|W}} There have been various tentative proposals for an [[Irish Sea Tunnel]]. During [[World War I]] the Irish Sea became known as "[[U-boat]] Alley", because the U-boats moved their emphasis from the [[Atlantic Ocean|Atlantic]] to the Irish Sea after the [[United States]] entered the war in 1917.<ref>''U-Boat Alley'' by Roy Stokes, published by Compuwreck, ISBN 0-9549186-0-6</ref><ref>The War in Maps: The Irish Sea, [http://uboat.net/maps/irish_sea.htm (Link)], UBoat.net</ref> :''See also: [[Transport in Ireland]], [[Transport in the United Kingdom]], [[Transport on the Isle of Man]]'' ==Cities and towns== Below is a list of cities and towns around the Irish Sea coasts in order of size. {| class="wikitable sortable" |- ! Rank ! City/Town ! County ! Region/Province ! Population ! Country |- | 1 | [[Dublin]] | [[Dublin Region]] | [[Leinster]] | 1,045,769 | {{IRL}} |- | 2 | [[Liverpool]] | [[Merseyside]] | [[North West England|North West]] | 447,500 | {{ENG}} |- | 3 | [[Belfast]] | [[County Antrim]] | [[Ulster]] | 276,459 | [[Image:NIShape.gif|30px]] [[Northern Ireland]] |- | 5 | [[Blackpool]] | [[Lancashire]] | [[North West England|North West]] | 142,900 | {{ENG}} |- | 6 | [[Southport]] | [[Merseyside]] | [[North West England|North West]] | 99,456 | {{ENG}} |- | 7 | [[Birkenhead]] | [[Merseyside]] | [[North West England|North West]] | 83,729 | {{ENG}} |- | 8 | [[Bangor, County Down|Bangor]] | [[County Down]] | [[Ulster]] | 76,851 | [[Image:NIShape.gif|30px]] [[Northern Ireland]] |- | 9 | [[Barrow-in-Furness]] | [[Cumbria]] | [[North West England|North West]] | 71,980 | {{ENG}} |- | 10 | [[Wallasey]] | [[Merseyside]] | [[North West England|North West]] | 58,710 | {{ENG}} |- | 11 | [[Morecambe]] | [[Lancashire]] | [[North West England|North West]] | 45,000 | {{ENG}} |- | 12 | [[Lytham St Annes]] | [[Lancashire]] | [[North West England|North West]] | 41,330 | {{ENG}} |- | 13 | [[Drogheda]] | [[County Louth]] | [[Leinster]] | 35,090 | {{IRL}} |- | 14 | [[Dundalk]] | [[County Louth]] | [[Leinster]] | 35,085 | {{IRL}} |- | 15 | [[Rhyl]] | [[Denbighshire]] | [[Clwyd]], [[Wales]] | 35,000 | {{WAL}} |- | 17 | [[Bray]] | [[County Wicklow]] | [[Leinster]] | 31,901 | {{IRL}} |- | 18 | [[Thornton-Cleveleys]] | [[Lancashire]] | [[North West England|North West]] | 31,157 | {{ENG}} |- | 19 | [[Colwyn Bay]] | [[Conwy]] | [[Clwyd]], [[Wales]] | 30,265 | {{WAL}} |- | 20 | [[Carrickfergus]] | [[County Antrim]] | [[Ulster]] | 27,201 | [[Image:NIShape.gif|30px]] [[Northern Ireland]] |- | 21 | [[Fleetwood]] | [[Lancashire]] | [[North West England|North West]] | 26.840 | {{ENG}} |- | 22 | [[Douglas, Isle of Man|Douglas]] | [[Middle (sheading)|Middle]] | [[Isle of Man]] | 26,218 | {{IOM}} |- | 20 | [[Workington]] | [[Cumbria]] | [[North West England|North West]] | 25,978 | {{ENG}} |- | 23 | [[Whitehaven]] | [[Cumbria]] | [[North West England|North West]] | 25,500 | {{ENG}} |- | 24 | [[Llandudno]] | [[Conwy]] | [[Clwyd]], [[Wales]] | 20,090 | {{WAL}} |} == Origin == <!--Marine Life?, Climate?, Temperature range?--> The Irish Sea has undergone a series of dramatic changes over the last 20,000 years as the last [[Ice age]] ended and was replaced by warmer conditions. At the height of the ice age the central part of the modern sea was probably a long [[freshwater]] [[lake]]. As the [[ice]] retreated 10,000 years ago the lake reconnected to the sea, becoming [[brackish]] and then fully [[Saline water|saline]] once again. == Environment == [[Image:IMG Brittas Bay1529.jpg|thumb|right|[[Brittas Bay]], on the [[County Wicklow]] [[coast]]]] === Biodiversity === {{Refimprove|section|date=March 2008}} The most accessible and possibly the greatest [[wildlife]] resource of the Irish Sea lies in its [[estuaries]]: particularly the [[Dee Estuary]], the [[Mersey Estuary]], the [[Ribble and Alt Estuaries|Ribble Estuary]], [[Morecambe Bay]], the [[Solway Firth]], [[Loch Ryan]], the [[Firth of Clyde]], [[Belfast Lough]], [[Strangford Lough]], [[Carlingford Lough]], [[Dundalk Bay]], [[Dublin Bay]] and [[Wexford Harbour]]. However, a lot of wildlife also depends on the [[cliff]]s, [[saltmarsh]]es and [[sand dune]]s of the adjoining [[shore]]s, the [[seabed]] and the open sea itself. The information on the [[invertebrate]]s of the seabed of the Irish Sea is rather patchy because it is difficult to survey such a large area, where underwater visibility is often poor and information often depends upon looking at material brought up from the seabed in mechanical grabs. However, the groupings of [[animal]]s present depend to a large extent on whether the seabed is composed of [[Rock (geology)|rock]], [[boulder]]s, [[gravel]], [[sand]], [[mud]] or even [[peat]]. In the soft [[sediment]]s seven types of community have been provisionally identified, variously dominated by [[brittle-star]]s, [[sea urchin]]s, [[worm]]s, [[mussel]]s, [[Tellina|tellins]], [[Peppery furrow shell|furrow-shell]]s, and tower-shells. Parts of the bed of the Irish Sea are very rich in wildlife. The seabed southwest of the Isle of Man is particularly noted for its rarities and diversity <ref>Barne, J.H., Robson, C.F., Kaznowska, S.S., Doody, J.P., & Davidson, N.C., eds. 1996. Coasts and seas of the United Kingdom. Region 13 Northern Irish Sea: [[Colwyn Bay]] to Stranraer, including the Isle of Man. [[Peterborough]], Joint Nature Conservation Committee, ISBN 1 873701 87 X</ref>, as are the [[horse mussel]] beds of Strangford Lough. [[Scallop]]s and [[queen scallop]]s are found in more gravelly areas. In the estuaries, where the bed is more sandy or muddy, the number of species is smaller but the size of their populations is larger. [[Brown shrimp]], [[cockle]]s and edible mussels support local [[fisheries]] in Morecambe Bay and the Dee Estuary and the estuaries are also important as nurseries for [[flatfish]], [[herring]] and [[sea bass]]. Muddy seabeds in deeper waters are home to populations of the [[Dublin Bay prawn]], also known as "scampi".<ref>Irish Sea Study Group Report, Part 1, NATURE CONSERVATION, Liverpool University Press, 1990 ISBN 0 85323 227 X</ref> The open sea is a complex habitat in its own right. It exists in three spatial dimensions and also varies over time and tide. For example, where freshwater flows into the Irish Sea in river estuaries its influence can extend far offshore as the freshwater is lighter and "floats" on top of the much larger body of saltwater until [[wind]] and [[temperature]] changes mix it in. Similarly, warmer water is less dense and seawater warmed in the inter-tidal zone may "float" on the colder offshore water. The amount of light penetrating the seawater also varies with depth and turbidity. This leads to differing populations of [[plankton]] in different parts of the sea and varying communities of animals that feed on these populations. However, increasing seasonal [[storm]]iness leads to greater mixing of water and tends to break down these divisions, which are more apparent when the weather is calm for long periods. Plankton includes [[virus]]es, [[bacteria]], [[plant]]s ([[phytoplankton]]) and animals ([[zooplankton]]) that drift in the sea. Most are microscopic, but some, such as the various species of [[jellyfish]] and [[Ctenophore|sea gooseberry]], can be much bigger. [[Diatom]]s and [[dinoflagellate]]s dominate the phytoplankton. Although they are microscopic plants, diatoms have hard shells and dinoflagellates have little [[tail]]s that propel them through the water. Phytoplankton populations in the Irish Sea have a spring "bloom" every April and May, when the seawater is generally at its greenest. [[Crustacean]]s, especially [[copepod]]s, dominate the zooplankton. However, many animals of the seabed, the open sea and the seashore spend their juvenile stages as part of the zooplankton. The whole plankton "soup" is vitally important, directly or indirectly, as a food source for most species in the Irish Sea, even the largest. The enormous [[basking shark]], for example, lives entirely on plankton and the [[leatherback turtle]]'s main food is jellyfish. A colossal diversity of [[invertebrate]] [[species]] live in the Irish Sea and its surrounding coastline, ranging from [[flower]]-like fan-worms to predatory [[Portunidae|swimming crabs]] to large [[chameleon]]-like [[cuttlefish]]. <ref>Irish Sea Study Group Report, Part 1, NATURE CONSERVATION, Liverpool University Press, 1990 ISBN 0 85323 227 X</ref> Some of the most significant for other wildlife are the reef-building species like the inshore horse mussel of Strangford Lough and the inter-tidal honeycomb worm of Morecambe Bay, [[Cumbria]] and [[Lancashire]]. These build up large structures over many years and, in turn, provide surfaces, nooks and crannies where other marine animals and plants may become established and live out some or all of their lives. There are quite regular records of live and stranded leatherback turtle in and around the Irish Sea. This species travels north to the waters off the [[British Isles]] every year following the swarms of jellyfish that form its prey. Loggerhead turtle, [[Ridley sea turtle]] and [[green turtle]] are found very occasionally in the Irish Sea but are generally unwell or dead when discovered. They have strayed or been swept out of their natural range further south into colder waters.<ref>[http://www.turtle.ie/index.htm]</ref> The estuaries of the Irish Sea are of international importance for [[bird]]s. They are vital feeding grounds on [[migration]] flyways for [[shorebird]]s travelling between the [[Arctic]] and [[Africa]]. Others depend on the milder climate as a refuge when continental Europe is in the grip of [[winter]].<ref>Irish Sea Study Group Report, Part 1, NATURE CONSERVATION, Liverpool University Press, 1990 ISBN 0 85323 227 X</ref>. Twenty-one species of [[seabird]] are reported as regularly nesting on [[beach]]es or cliffs around the Irish Sea. Huge populations of the [[sea duck]], [[common scoter]], spend winters feeding in shallow waters off eastern Ireland, Lancashire and [[North Wales]]<ref>Irish Sea Study Group Report, Part 1, NATURE CONSERVATION, Liverpool University Press, 1990 ISBN 0 85323 227 X</ref>. [[Whale]]s, [[dolphin]]s and [[porpoise]]s all frequent the Irish Sea, but knowledge of how many there may be and where they go is somewhat sketchy. About a dozen species have been recorded since 1980, but only three are seen fairly often. These are the [[harbour porpoise]], [[bottlenose dolphin]] and [[common dolphin]]. The more rarely seen species are [[minke whale]], [[fin whale]], [[sei whale]], [[sperm whale]], [[northern bottlenose whale]], [[long-finned pilot whale]], [[orca]], [[white-beaked dolphin]], [[striped dolphin]] and [[Risso's dolphin]].<ref>Irish Sea Study Group Report, Part 1, NATURE CONSERVATION, Liverpool University Press, 1990 ISBN 0 85323 227 X</ref>. The common or [[harbour seal]] and the [[grey seal]] are both resident in the Irish Sea. Common [[seal]]s breed in Strangford Lough, grey seals in southwest Wales and, in small numbers, on the Isle of Man. Grey seals haul out, but do not breed, off [[Hilbre Island|Hilbre]] and [[Walney Island|Walney]] islands, [[Merseyside]], the [[Wirral]], Barrow-in-Furness Borough, and Cumbria.<ref>Irish Sea Study Group Report, Part 1, NATURE CONSERVATION, Liverpool University Press, 1990 ISBN 0 85323 227 X</ref> === Radioactive pollution === The Irish Sea has been described by [[Greenpeace]] as the most [[Radioactive contamination|radioactively contaminated]] sea in the world with some "eight million [[litre]]s of [[nuclear waste]]" discharged into it each day from [[Sellafield]] reprocessing plants, contaminating seawater, sediments and marine life.<ref>Sellafield nuclear reprocessing facility, [http://www.greenpeace.org.uk/nuclear/sellafield-nuclear-reprocessing-facility (Link)], [[Greenpeace]]</ref> Low-level [[Radioactive decay|radioactive]] waste has been discharged into the Irish Sea as part of operations at Sellafield since 1952. The rate of discharge began to accelerate in the mid- to late 1960s, reaching a peak in the 1970s and generally declining significantly since then. As an example of this profile, discharges of [[plutonium]] (specifically <sup>241</sup>Pu) peaked in 1973 at 2,755[[Becquerel|TBq]]<ref name="EnvAgTab3">The Past, Current and Future Radiological Impact of the Sellafield Marine Discharges on the People Living in the Coastal Communities Surrounding the Irish Sea, [http://publications.environment-agency.gov.uk/pdf/STRP290-e-p.pdf (Link)], [[Environment Agency]] – Table 3</ref> falling to 8.1TBq by 2004.<ref name="BNGAnnRpt2004">Monitoring our Environment - Discharges and Monitoring in the UK - Annual Report 2004, [http://www.britishnucleargroup.com/pdf/BNGSL%202004%20Monitoring%20report%20final.pdf (Link)], [[British Nuclear Group]] – Table 2</ref> Improvements in the treatment of waste in 1985 and 1994 resulted in further reductions in radioactive waste discharge although the subsequent processing of a backlog resulted in increased discharges of certain types of radioactive waste. Discharges of [[technetium]] in particular rose from 6.1TBq in 1993 to a peak of 192TBq in 1995 before dropping back to 14TBq in 2004.<ref name="EnvAgTab3" /> <ref name="BNGAnnRpt2004" /> In total 22PBq of <sup>241</sup>Pu was discharged over the period 1952 to 1998.<ref>Leon et al, 2000, [http://homepage.eircom.net/~radphys/scope.pdf (Link)], The environmental impact of the Sellafield discharges – p2</ref> Current rates of discharge for many [[radionuclides]] are at least 100 times lower than they were in the 1970s.<ref>Quality Status Report – Regional QSR III, [http://www.ospar.org/eng/doc/pdfs/R3C4.pdf (Link)], [[OSPAR]] – Chapter 4 Chemistry, p64</ref> Analysis<ref>Leon et al, 2000, [http://homepage.eircom.net/~radphys/scope.pdf (Link)], The environmental impact of the Sellafield discharges – sections 3-4</ref><ref>McMahon et al, 2005, [http://www.edpsciences.org/articles/radiopro/pdf/2005/02/p424.pdf?access=ok (Link)], Transfer of conservative and non-conservative radionuclides from the Sellafield Nuclear Fuel Reprocessing plant to the coastal waters of Ireland</ref> of the distribution of radioactive contamination after discharge reveals that mean sea currents result in much of the more soluble elements such as [[caesium]] being flushed out of the Irish Sea through the North Channel about a year after discharge. Measurements of technetium concentrations post-1994 has produced estimated transit times to the North Channel of around six months with peak concentrations off the northeast Irish coast occurring 18-24 months after peak discharge. Less soluble elements such as plutonium are subject to much slower redistribution. Whilst concentrations have declined in line with the reduction in discharges they are markedly higher in the eastern Irish Sea compared to the western areas. The dispersal of these elements is closely associated with sediment activity, with [[mud]]dy deposits on the seabed acting as sinks, soaking up an estimated 200[[kg]] of [[plutonium]].<ref>Quality Status Report – Regional QSR III, [http://www.ospar.org/eng/doc/pdfs/R3C4.pdf (Link)], [[OSPAR]] – Chapter 4 Chemistry, p66</ref> The highest concentration is found in the eastern Irish Sea in sediment banks lying parallel to the Cumbrian coast. This area acts as a significant source of wider contamination as radionuclides are dissolved once again. Studies have revealed that 80% of current sea water contamination by caesium is sourced from sediment banks, whilst plutonium levels in the western sediment banks between the Isle of Man and the Irish coast are being maintained by contamination redistributed from the eastern sediment banks. The consumption of [[seafood]] harvested from the Irish Sea is the main pathway for exposure of [[human]]s to radioactivity.<ref>Radioactive Monitoring of the Irish Environment 2003-2005, [http://www.rpii.ie/Download/Env_Mon_Rep_03_05.pdf (Link)], [[RPII]] – p7</ref> The environmental monitoring report for the period 2003 to 2005 published by the [[Radiological Protection Institute of Ireland]] (RPII) reported that in 2005 average quantities of radioactive contamination found in seafood ranged from less than 1[[Bq/kg]] for fish to under 44Bq/kg for mussels.<ref>Radioactive Monitoring of the Irish Environment 2003-2005, [http://www.rpii.ie/Download/Env_Mon_Rep_03_05.pdf (Link)], [[RPII]] – Table 45</ref> Doses of man-made radioactivity received by the heaviest consumers of seafood in Ireland in 2005 was 1.10[[Sievert|µSv]].<ref>Radioactive Monitoring of the Irish Environment 2003-2005, [http://www.rpii.ie/Download/Env_Mon_Rep_03_05.pdf (Link)], [[RPII]] – p26</ref> This compares with a corresponding dosage of radioactivity naturally occurring in the seafood consumed by this group of 148µSv and a total average dosage in [[Ireland]] from all sources of 3620µSv.<ref>Radioactive Monitoring of the Irish Environment 2003-2005, [http://www.rpii.ie/Download/Env_Mon_Rep_03_05.pdf (Link)], [[RPII]] – p27</ref> In terms of risk to this group, heavy consumption of seafood generates a 1 in 18 million chance of causing [[cancer]]. The general risk of contracting cancer in Ireland is 1 in 522. In the UK, the heaviest seafood consumers in Cumbria received a radioactive dosage attributable to Sellafield discharges of 0.22mSv (220µSv) in 2005.<ref>Radioactivity in Food and the Environment 2005, [http://www.cefas.co.uk/Publications/rife/rife11.pdf (Link)], [[Cefas]] – p11</ref> This compares to average annual dose of naturally sourced radiation received in the UK of 2.23mSv (2230µSv).<ref>Watson et al, 2005 [http://www.hpa.org.uk/radiation/publications/hpa_rpd_reports/2005/hpa_rpd_001.pdf (Link)], [[Health Protection Agency]] – Ionising Radiation Exposure of the UK Population: 2005 Review</ref> == Oil and gas exploration == === East Irish Sea Basin === {{Unreferenced|section|date=March 2008}} With 7.5 trillion [[cubic feet]] (210 [[km³]]) of [[natural gas]] and 176 million barrels (28,000,000 [[m³]]) of [[petroleum]] estimated by the field operators as initially recoverable [[hydrocarbon]] reserves from eight producing fields (DTI, 2001), the East Irish Sea Basin is at a mature exploration phase. Early [[Silesian (age)|Namurian]] basinal [[mudstone]]s are the source rocks for these hydrocarbons. Production from all fields is from fault-bounded traps of the Lower [[Triassic]] formation, principally the aeolian Sherwood Sandstone reservoir, top-sealed by younger Triassic continental mudstones and [[evaporite]]s. Future [[mineral exploration]] will initially concentrate on extending this play, but there remains largely untested potential also for gas and oil within widespread [[Carboniferous]] [[fluvial]] [[sandstone]] reservoirs. This play requires intraformational mudstone seal units to be present, as there is no top-seal for reservoirs subcropping the regional base [[Permian]] [[unconformity]] in the east of the basin, and Carboniferous [[stratum|strata]] crop out at the sea bed in the west. === Caernarfon Bay Basin === {{Unreferenced|section|date=March 2008}} The [[Caernarfon Bay]] basin contains up to 7&nbsp;km³ of Permian and Triassic syn-rift sediments in an asymmetrical [[graben]] that is bounded to the [[north]] and [[south]] by Lower [[Paleozoic]] [[massif]]s. Only two exploration wells have been drilled so far, and there remain numerous undrilled targets in tilted fault block plays. As in the East Irish Sea Basin, the principal target reservoir is the Lower Triassic, Sherwood Sandstone, top-sealed by younger Triassic mudstones and evaporites. Wells in the Irish Sector to the west have demonstrated that pre-rift, [[Westphalian]] [[coal measure]]s are excellent hydrocarbon source rocks, and are at peak maturity for gas generation (Maddox et al., 1995). [[seismogram|Seismic profiles]] clearly image these strata continuing beneath a basal Permian unconformity into at least the western part of the Caernarfon Bay Basin. The timing of gas generation presents the greatest exploration risk. Maximum burial of, and primary gas migration from, the source rocks could have terminated as early as the [[Jurassic]], whereas many of the tilted fault blocks were reactivated or created during [[Paleogene]] inversion of the basin. However, it is also possible that a secondary gas charge occurred during regional heating associated with intrusion of Paleogene [[Dyke (geology)|dyke]]s, such as those that crop out nearby on the coastline of north Wales. (Floodpage et al., 1999) have invoked this second phase of Paleogene hydrocarbon generation as an important factor in the charging of the East Irish Sea Basin’s oil and gas fields. It is not clear as yet whether aeromagnetic anomalies in the southeast of Caernarfon Bay are imaging a continuation of the dyke swarm into this area too, or whether they are instead associated with deeply buried Permian syn-rift [[volcanic]]s. Alternatively, the fault block traps could have been recharged by [[exsolution]] of [[methane]] from formation [[brine]]s as a direct result of the [[Tertiary]] uplift (cf. Doré and Jensen, 1996). === The Cardigan Bay Basin === The [[Cardigan Bay]] Basin forms a continuation into British waters of Ireland’s North Celtic Sea Basin, which has two producing gas fields. The basin comprises a south-easterly deepening half-graben near the Welsh coastline, although its internal structure becomes increasingly complex towards the southwest. Permian to Triassic, syn-rift sediments within the basin are less than 3&nbsp;[[km]] thick and are overlain by up to 4&nbsp;km of Jurassic strata, and locally also by up to 2&nbsp;km of Paleogene fluvio-deltaic sediments. The basin has a proven petroleum system, with potentially producible gas reserves at the Dragon discovery near the UK/ROI median line, and oil shows in a further three wells. The Cardigan Bay Basin contains multiple reservoir targets, which include the Lower Triassic (Sherwood Sandstone), [[Middle Jurassic]] shallow marine sandstones and limestone (Great [[Oolite]]), and Upper Jurassic fluvial sandstone, the reservoir for the Dragon discovery. The most likely hydrocarbon source rocks are [[Early Jurassic]] marine mudstones. These are fully mature for oil generation in the west of the British sector, and are mature for gas generation nearby in the Irish sector. Gas-prone, Westphalian pre-rift coal measures may also be present at depth locally. The Cardigan Bay Basin was subjected to two Tertiary phases of compressive uplift, whereas maximum burial that terminated primary hydrocarbon generation was probably around the end of the [[Cretaceous]], or earlier if Cretaceous strata, now missing, were never deposited in the basin. Despite the Tertiary structuration, the Dragon discovery has proved that potentially commercial volumes of hydrocarbons were retained at least locally in Cardigan Bay. In addition to undrilled structural traps, the basin contains untested potential for stratigraphic entrapment of hydrocarbons near synsedimentary faults, especially in the Middle Jurassic section.<ref>"Petroleum prospectivity of the principal sedimentary basins on the United Kingdom Continental Shelf" [http://www.og.dti.gov.uk/UKpromote/summary_UKCS_2003.pdf (pdf)], [[Department of Trade and Industry]], 2003</ref><ref>[[Liverpool Bay]], [[England]][http://www.visitorcentre-bhpbilliton.com/ (Link)], BHP Oil Ltd</ref> === The Liverpool Bay Development === {{Unreferenced|section|date=March 2008}} The Liverpool Bay Development is [[BHP Billiton Petroleum]]'s largest operated asset. It comprises the integrated development of five offshore oil and gas fields in the Irish Sea: * Douglas oil field * Hamilton gas field * Hamilton North gas field * Hamilton East gas field * Lennox oil and gas fiel Oil is produced from the Lennox and Douglas fields. It is then treated at the Douglas Complex and piped 17 kilometres to an oil storage barge ready for export by tankers. Gas is produced from the Hamilton, Hamilton North and Hamilton East reservoirs. After initial processing at the [[Douglas Complex]] the gas is piped by [[subsea pipeline]] to the [[Point of Ayr]] gas terminal for further processing. The gas is then sent by onshore pipeline to [[PowerGen]]'s [[combined cycle gas turbine]] [[power station]] at [[Connah's Quay]]. PowerGen is the sole purchaser of gas from the Liverpool Bay development. The Liverpool Bay development comprises four offshore platforms. Offshore storage and loading facilities. The onshore gas processing terminal at Point of Ayr. Production first started at each filed as follows: Hamilton North in 1995, Hamilton in 1996, Douglas in 1996, Lennox (oil only) in 1996 and Hamilton East 2001. The first contract gas sales were in 1996. == Proposed tunnel projects == {{main|Irish Sea Tunnel}} Discussions of linking Britain to Ireland began in 1895,<ref>"TUNNEL UNDER THE SEA", [[The Washington Post]], May 2, 1897 [http://pqasb.pqarchiver.com/washingtonpost_historical/access/282943272.html?dids=282943272:282943272&FMT=ABS&FMTS=ABS:FT&date=MAY+02%2C+1897&author=&pub=The+Washington+Post&desc=TUNNEL+UNDER+THE+SEA&pqatl=google (Archive link)]</ref> with an application £15,000 towards the cost of carrying out borings and soundings in the [[North Channel (Britain and Ireland)|North Channel]] to see if a tunnel between Ireland and Scotland was viable. Sixty years later [[Harford Hyde|Harford Montgomery Hyde]], [[Unionists (Ireland)|Unionist]] MP for North Belfast, called for the building of such a tunnel.<ref>"[[An Irishman's Diary]]" by [[Wesley Boyd]], [http://www.ireland.com/newspaper/opinion/2004/0207/3742943993DIFEB7.html (Link)], [[The Irish Times]], Feb 2004 (subscription required)</ref> A tunnel project has been discussed several times in the [[Dáil Éireann|Irish Parliament]].<ref>Written Answers. - Sea Transport, [http://historical-debates.oireachtas.ie/D/0384/D.0384.198811160027.html (Link)], [[Dáil Éireann]] - Volume 384 - 16 November, 1988</ref><ref>Written Answers. - Irish Sea Railway Ferry, [http://historical-debates.oireachtas.ie/D/0434/D.0434.199310190089.html (Link)], [[Dáil Éireann]] - Volume 434 - 19 October, 1993</ref><ref>Written Answers. - Ireland-UK Tunnel, [http://www.oireachtas-debates.gov.ie/plweb-cgi/fastweb?state_id=1140781637&view=oho-view&docrank=44&numhitsfound=315&query=Irish%20sea%20tunnel&query_rule=%28%28$query1%29%3C%3DDATE%3C%3D%28$query2%29%29%20AND%20%28%28$query4%29%29%3ASPEAKER%20AND%20%28%28$query5%29%29%3Aheading%20AND%20%28%28$query6%29%29%3ACATEGORY%20AND%20%28%28$query3%29%29%3Ahouse%20AND%20%28%28$query7%29%29%3Avolume%20AND%20%28%28$query8%29%29%3Acolnumber%20AND%20%28%28$query%29%29&docid=383293&docdb=Debates&dbname=Debates&starthit=25&sorting=none&operator=and&TemplateName=predoc.tmpl&setCookie=1 (Link)], [[Dáil Éireann]] - Volume 517 - 29 March, 2000</ref><ref>Written Answers - Transport Projects, [http://www.oireachtas-debates.gov.ie/plweb-cgi/fastweb?state_id=1140781475&view=oho-view&docrank=4&numhitsfound=315&query=Irish%20sea%20tunnel&query_rule=%28%28$query1%29%3C%3DDATE%3C%3D%28$query2%29%29%20AND%20%28%28$query4%29%29%3ASPEAKER%20AND%20%28%28$query5%29%29%3Aheading%20AND%20%28%28$query6%29%29%3ACATEGORY%20AND%20%28%28$query3%29%29%3Ahouse%20AND%20%28%28$query7%29%29%3Avolume%20AND%20%28%28$query8%29%29%3Acolnumber%20AND%20%28%28$query%29%29&docid=477035&docdb=Debates&dbname=Debates&sorting=none&operator=and&TemplateName=predoc.tmpl&setCookie=1 (Link)], [[Dáil Éireann]] - Volume 597 - 15 February, 2005</ref> Several potential Irish Sea tunnel projects have been proposed, most recently the "Tusker Tunnel" between the ports of Rosslare and Fishguard proposed by The Institute of Engineers of Ireland in 2004.<ref>A Vision of Transport in Ireland in 2050, [http://www.iei.ie/Publications/GetPublicationDetails.pasp?PublicationID=69&Module=Papers&txt_freetext=&RecordsPerPage=1000&PageNumber=1&MenuID=24 IEI report (pdf)], The Irish Academy of Engineers, 21/12/2004</ref><ref>Tunnel 'vision' under Irish Sea, [http://news.bbc.co.uk/1/hi/wales/south_west/4121001.stm (link)], [[BBC]] news, Thursday, 23 December, 2004</ref> A different proposed route between Dublin and Holyhead, was proposed in 1997 by a British engineering firm, Symonds, for a rail tunnel from Dublin to Holyhead. Either tunnel, at {{km to mi|num=80|abbr=no|spell=Commonwealth|precision=2|wiki=yes}}, would be by far the longest in the world, and would cost an estimated €20 billion. [[Image:IMG DublinBay1467a.jpg|thumb|280px|Dublin Bay on the west coast of Irish Sea]] == Wind power == One of the world's largest wind farms is being developed on [[Arklow]] Bank<ref>Arklow Bank Wind Park [http://www.airtricity.com/ireland/wind_farms/offshore/operating/arklow_bank/index.xml (Link)][[Airtricity]]</ref>, [[Arklow Bank Wind Park]], about 10&nbsp;km off the coast of [[County Wicklow]] in the south Irish Sea. The site currently has seven GE 3.6 MW [[turbine]]s, each with 104 m [[rotor]] diameters, the world's first commercial application of offshore wind turbines over three [[megawatt]]s in size. The operating company, [[Airtricity]], has indefinite plans for nearly 100 further turbines on the site. Further wind turbine sites include: * The [[North Hoyle]] site 4-5 miles off the coast from [[Rhyl]] and [[Prestatyn]] in [[North Wales]], containing thirty 2 MW turbines.<ref>[http://www.natwindpower.co.uk/northhoyle/ Northhoyle]</ref>, NPower Renewables * [[Burbo Bank]] site 10km off the north [[Wirral Peninsula|Wirral]] coast * A site in the Solway Firth is being developed * Turbines are being erected off the coast of Walney Island * Turbines are being erected off the coast of [[Clogherhead]] (to be called the [[Oriel Wind Farm]])<ref>[http://www.orielwind.com/project_status.html Oriel Wind project status]</ref> == References == {{Reflist}} {{coor title dms|53|43|18|N|5|10|38|W|type:waterbody}} [[Category:Irish Sea]] [[Category:Landforms of Ireland]] [[Category:Marginal seas of the Atlantic Ocean]] [[Category:Seas]] [[Category:Shipping Forecast areas]] [[ang:Īrisc Sǣ]] [[ar:البحر الأيرلندي]] [[ast:Mar d'Irlanda]] [[be:Ірландскае мора]] [[bs:Irsko more]] [[br:Mor Iwerzhon]] [[bg:Ирландско море]] [[ca:Mar d'Irlanda]] [[cv:Ирланди тинĕсĕ]] [[cs:Irské moře]] [[cy:Môr Iwerddon]] [[da:Irske Hav]] [[de:Irische See]] [[et:Iiri meri]] [[es:Mar de Irlanda]] [[eo:Irlanda Maro]] [[fr:Mer d'Irlande]] [[ga:Muir Éireann]] [[gv:Mooir Vannin]] [[gl:Mar de Irlanda]] [[ko:아일랜드 해]] [[hr:Irsko more]] [[is:Írlandshaf]] [[it:Mare d'Irlanda]] [[he:הים האירי]] [[ku:Deryaya Îrlanda]] [[lv:Īrijas jūra]] [[lb:Irescht Mier]] [[lt:Airijos jūra]] [[nl:Ierse Zee]] [[ja:アイリッシュ海]] [[no:Irskesjøen]] [[nn:Irskesjøen]] [[oc:Mar d'Irlanda]] [[pl:Morze Irlandzkie]] [[pt:Mar da Irlanda]] [[ro:Marea Irlandei]] [[ru:Ирландское море]] [[sq:Deti Irlandez]] [[simple:Irish Sea]] [[sk:Írske more]] [[sl:Irsko morje]] [[sr:Ирско море]] [[fi:Irlanninmeri]] [[sv:Irländska sjön]] [[tr:İrlanda Denizi]] [[uk:Ірландське море]] [[zh:愛爾蘭海]]