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151-564: Rockall ( / ˈ r ɒ k ɔː l / ) is an uninhabitable granite islet in the North Atlantic Ocean . The United Kingdom claims that Rockall lies within its territorial sea and is part of its territory, but this claim is not recognised by Ireland . It and the nearby skerries of Hasselwood Rock and Helen's Reef are the only emergent parts of the Rockall Plateau . The rock was formed by magmatism as part of

302-663: A féth fíada ('magic mist'). They are said to have travelled from the north of the world, but then were forced to live underground in the sídhe after the coming of the Irish. In some tales, such as Baile in Scáil , kings receive affirmation of their legitimacy from one of the Tuath Dé, or a king's right to rule is affirmed by an encounter with an otherworldly woman (see sovereignty goddess ). The Tuath Dé can also bring doom to unrightful kings. The medieval writers who wrote about

453-420: A completely crystalline rock. Granitic rocks mainly consist of feldspar , quartz , mica , and amphibole minerals , which form an interlocking, somewhat equigranular matrix of feldspar and quartz with scattered darker biotite mica and amphibole (often hornblende ) peppering the lighter color minerals. Occasionally some individual crystals ( phenocrysts ) are larger than the groundmass , in which case

604-639: A territorial sea extending 12 nautical miles (22 kilometres). Ireland's position is that Rockall does not even generate a 12-nautical-mile territorial sea for the United Kingdom owing to the UK's uncertain title to Rockall. Ireland does not recognise the UK's claim, although it has never sought to claim sovereignty of Rockall for itself. The consistent position of successive Irish governments has been that Rockall and similar rocks and skerries have no significance for establishing legal claims to mineral rights in

755-430: A "goddess of poets". Writing in the seventh century, Tírechán explained the sídh folk as "earthly gods" (Latin dei terreni ), while Fiacc's Hymn says the Irish adored the sídh before the coming of Saint Patrick . Several of the Tuath Dé are cognate with ancient Celtic deities: Lugh with Lugus , Brigid with Brigantia , Nuada with Nodons , and Ogma with Ogmios . Nevertheless, John Carey notes that it

906-610: A Scottish rival. It instead missed and landed in the Irish Sea – the pebble left behind formed Rockall, while the clump became the Isle of Man and the void left behind filled with water and eventually became Lough Neagh . There can be no place more desolate, despairing and awful. The 17.15-metre-high (56.3 ft) rock has been noted in written records since the late 16th century. In the 20th century, its location became relevant due to potential oil and fishing rights that might accrue to

1057-563: A basaltic magma to a granitic magma, but the quantities produced are small. For example, granitic rock makes up just 4% of the exposures in the South Sandwich Islands . In continental arc settings, granitic rocks are the most common plutonic rocks, and batholiths composed of these rock types extend the entire length of the arc. There are no indication of magma chambers where basaltic magmas differentiate into granites, or of cumulates produced by mafic crystals settling out of

1208-409: A book entitled Fragment of Voyages and Travels Including Anecdotes of a Naval Life . The next landing, in the summer of 1862, was by a Mr Johns of HMS  Porcupine whilst the ship was making a survey of the sea bed prior to the laying of a transatlantic telegraph cable . Johns managed to gain foothold on the island, but failed to reach the summit. On 18 September 1955, Rockall was annexed by

1359-748: A brass plaque on Hall's Ledge and hoisted the Union Flag to stake the UK's claim. The inscription on the plaque read: BY AUTHORITY OF HER MAJESTY QUEEN ELIZABETH THE SECOND , BY THE GRACE OF GOD OF THE UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND AND OF HER OTHER REALMS AND TERRITORIES, QUEEN, HEAD OF THE COMMONWEALTH , DEFENDER OF THE FAITH , ETC. ETC. ETC. AND IN ACCORDANCE WITH HER MAJESTY'S INSTRUCTIONS DATED 14. 9. 55. A LANDING WAS EFFECTED ON THIS DAY UPON THE ISLAND OF ROCKALL FROM H.M.S. VIDAL. THE UNION FLAG WAS HOISTED AND POSSESSION OF THE ISLAND WAS TAKEN IN THE NAME OF HER MAJESTY. [Signed] R H Connell, CAPTAIN , H.M.S. VIDAL, 18 SEPTEMBER 1955 It

1510-422: A desire to record their native culture and hostility to pagan beliefs, resulting in some of the gods being euhemerised . Many of the later sources may also have formed parts of a propaganda effort designed to create a history for the people of Ireland that could bear comparison with the mythological descent of their British invaders from the founders of Rome, as promulgated by Geoffrey of Monmouth and others. There

1661-520: A diapir it would expend far too much energy in heating wall rocks, thus cooling and solidifying before reaching higher levels within the crust. Fracture propagation is the mechanism preferred by many geologists as it largely eliminates the major problems of moving a huge mass of magma through cold brittle crust. Magma rises instead in small channels along self-propagating dykes which form along new or pre-existing fracture or fault systems and networks of active shear zones. As these narrow conduits open,

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1812-517: A few (known as leucogranites ) contain almost no dark minerals. Granite is nearly always massive (lacking any internal structures), hard (falling between 6 and 7 on the Mohs hardness scale) , and tough. These properties have made granite a widespread construction stone throughout human history. The word "granite" comes from the Latin granum , a grain, in reference to the coarse-grained structure of such

1963-506: A few hours on HF frequencies before they had to close down due to approaching bad weather. The Islands on the Air number EU-189 was issued to Rockall as a result of this activation. In 2010, it was revealed that the plaque had gone missing. Andy Strangeway , a British adventurer, announced his intention to land on the island and affix a replacement plaque in June 2010. Comhairle nan Eilean Siar ,

2114-610: A granite that is derived from partial melting of metasedimentary rocks may have more alkali feldspar, whereas a granite derived from partial melting of metaigneous rocks may be richer in plagioclase. It is on this basis that the modern "alphabet" classification schemes are based. The letter-based Chappell & White classification system was proposed initially to divide granites into I-type (igneous source) granite and S-type (sedimentary sources). Both types are produced by partial melting of crustal rocks, either metaigneous rocks or metasedimentary rocks. I-type granites are characterized by

2265-631: A group of manuscripts that originated in the West of Ireland in the late 14th century or the early 15th century: The Yellow Book of Lecan , The Great Book of Lecan and The Book of Ballymote . The first of these is in the Library of Trinity College and the others are in the Royal Irish Academy. The Yellow Book of Lecan is composed of sixteen parts and includes the legends of Fionn Mac Cumhail, selections of legends of Irish Saints, and

2416-599: A group of stories of visits to the Irish Other World (which may be westward across the sea, underground, or simply invisible to mortals). The most famous, Oisin in Tir na nÓg belongs to the Fenian Cycle, but several free-standing adventures survive, including The Adventure of Conle , The Voyage of Bran mac Ferbail , and The Adventure of Lóegaire . The voyages, or immrama , are tales of sea journeys and

2567-565: A high content of sodium and calcium, and by a strontium isotope ratio, Sr/ Sr, of less than 0.708. Sr is produced by radioactive decay of Rb, and since rubidium is concentrated in the crust relative to the mantle, a low ratio suggests origin in the mantle. The elevated sodium and calcium favor crystallization of hornblende rather than biotite. I-type granites are known for their porphyry copper deposits. I-type granites are orogenic (associated with mountain building) and usually metaluminous. S-type granites are sodium-poor and aluminum-rich. As

2718-405: A level area that was drilled to take the anchorages for the light beacon that was installed the following year. Two phosphor bronze plates were chased into the wall above Hall's Ledge, each secured by four 80-tonne rock-anchor bolts; there was no evidence of the brass plate installed in 1955. Establishing that the rock is part of the United Kingdom and its development as a light beacon facilitated

2869-824: A much higher proportion of clay with the Cecil soil series a prime example of the consequent Ultisol great soil group. Granite is a natural source of radiation , like most natural stones. Potassium-40 is a radioactive isotope of weak emission, and a constituent of alkali feldspar , which in turn is a common component of granitic rocks, more abundant in alkali feldspar granite and syenites . Some granites contain around 10 to 20 parts per million (ppm) of uranium . By contrast, more mafic rocks, such as tonalite, gabbro and diorite , have 1 to 5 ppm uranium, and limestones and sedimentary rocks usually have equally low amounts. Many large granite plutons are sources for palaeochannel -hosted or roll front uranium ore deposits , where

3020-478: A mythical rock which is supposed to appear three times, its last appearance being at the end of the world: " Nuair a thig Rocabarra ris, is dual gun tèid an Saoghal a sgrios ". ('When Rocabarra returns, the world will likely come to be destroyed'). Rockall's name has also been used in Irish mythology ; one story describes how legendary giant Fionn mac Cumhaill (Finn McCool) scooped up a chunk of Ireland to fling at

3171-591: A nation recognised as having a legitimate claim to it. In 1955 the British landed on Rockall and claimed it for the United Kingdom. The United Kingdom formally annexed the islet in 1972. According to Ian Mitchell, Rockall was terra nullius (owned by no one) until the 1955 British claim was made. Rockall gives its name to one of the sea areas named in the shipping forecast provided by the British Meteorological Office . Rockall has been

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3322-536: A peculiar mineralogy and geochemistry, with particularly high silicon and potassium at the expense of calcium and magnesium and a high content of high field strength cations (cations with a small radius and high electrical charge, such as zirconium , niobium , tantalum , and rare earth elements .) They are not orogenic, forming instead over hot spots and continental rifting, and are metaluminous to mildly peralkaline and iron-rich. These granites are produced by partial melting of refractory lithology such as granulites in

3473-411: A point of interest for adventurers and amateur radio operators, who have variously landed on or briefly occupied the islet. Fewer than 20 individuals have ever been confirmed to have landed on Rockall, and the longest known continuous occupation is 45 days (achieved in 2014 by a solo person). In a House of Commons debate in 1971, William Ross , Labour MP for Kilmarnock, said: "More people have landed on

3624-568: A range of hills, formed by the metamorphic aureole or hornfels . Granite often occurs as relatively small, less than 100 km stock masses ( stocks ) and in batholiths that are often associated with orogenic mountain ranges. Small dikes of granitic composition called aplites are often associated with the margins of granitic intrusions . In some locations, very coarse-grained pegmatite masses occur with granite. Granite forms from silica-rich ( felsic ) magmas. Felsic magmas are thought to form by addition of heat or water vapor to rock of

3775-415: A result, they contain micas such as biotite and muscovite instead of hornblende. Their strontium isotope ratio is typically greater than 0.708, suggesting a crustal origin. They also commonly contain xenoliths of metamorphosed sedimentary rock, and host tin ores. Their magmas are water-rich, and they readily solidify as the water outgasses from the magma at lower pressure, so they less commonly make it to

3926-696: A seismic survey of the Rockall Bank and the Hatton Bank in July 2004, as part of the Irish National Seabed Survey . The island's only permanent multicellular inhabitants are common periwinkles and other marine molluscs . Small numbers of seabirds, mainly fulmars , northern gannets , black-legged kittiwakes , and common guillemots , use the rock for resting in summer, and gannets and guillemots occasionally breed successfully if

4077-413: A storm, Hancock did remain on the island for 45 days, beating McClean's occupancy record by five days. In May 2023 Cam Cameron, a science teacher and former Gordon Highlander , began an attempt to stay 60 days on Rockall to raise funds for military charities. He was accompanied to the rock by a radio operator, Adrian Styles, and Bulgarian mountaineer Emil Bergmann, both of whom planned to stay with him for

4228-769: A succession of peoples, the fifth of whom was the people known as the Tuatha Dé Danann ("Peoples of the Goddess Danu"), who were believed to have inhabited the island before the arrival of the Gaels , or Milesians . They faced opposition from their enemies, the Fomorians , led by Balor of the Evil Eye. Balor was eventually slain by Lugh Lámfada (Lugh of the Long Arm) at the second battle of Magh Tuireadh. With

4379-523: A triad and connected with sovereignty and sacred animals. They guard the battlefield and those who do battle, and according to the stories in the Táin Bó Cúailnge , some of them may instigate and direct war themselves. The main goddesses of battle are The Morrígan, Macha, and Badb . Other warrior women are seen in the role of training warriors in the Fianna bands, such as Liath Luachra , one of

4530-451: A week and then leave. The group landed on Rockall on 30 May, having sailed from Inverkip on the Firth of Clyde. The attempt ended after 30 days when deteriorating weather conditions meant Cameron had to be rescued by HM Coastguard. The "Round Rockall" sailing race, sponsored by Galway Bay Sailing Club, runs from Galway , Ireland, around Rockall and back. It was held in 2012 to coincide with

4681-466: Is grus , which is often made up of coarse-grained fragments of disintegrated granite. Climatic variations also influence the weathering rate of granites. For about two thousand years, the relief engravings on Cleopatra's Needle obelisk had survived the arid conditions of its origin before its transfer to London. Within two hundred years, the red granite has drastically deteriorated in the damp and polluted air there. Soil development on granite reflects

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4832-545: Is microgranite . The extrusive igneous rock equivalent of granite is rhyolite . Granitic rock is widely distributed throughout the continental crust . Much of it was intruded during the Precambrian age; it is the most abundant basement rock that underlies the relatively thin sedimentary veneer of the continents. Outcrops of granite tend to form tors , domes or bornhardts , and rounded massifs . Granites sometimes occur in circular depressions surrounded by

4983-517: Is 3–6·10 Pa·s. The melting temperature of dry granite at ambient pressure is 1215–1260 °C (2219–2300 °F); it is strongly reduced in the presence of water, down to 650 °C at a few hundred megapascals of pressure. Granite has poor primary permeability overall, but strong secondary permeability through cracks and fractures if they are present. A worldwide average of the chemical composition of granite, by weight percent, based on 2485 analyses: The medium-grained equivalent of granite

5134-602: Is a sea-serpent-like monster in Irish mythology and folklore. These monsters were believed to inhabit many lakes and rivers in Ireland and there are legends of saints, especially St. Patrick, and heroes fighting them. The three main manuscript sources for Irish mythology are the late 11th/early 12th century Lebor na hUidre (Book of the Dun Cow), which is in the library of the Royal Irish Academy , and

5285-410: Is an excess of aluminum beyond what can be taken up in feldspars (Al 2 O 3 > CaO + K 2 O + Na 2 O) are described as peraluminous , and they contain aluminum-rich minerals such as muscovite . The average density of granite is between 2.65 and 2.75 g/cm (165 and 172 lb/cu ft), its compressive strength usually lies above 200 MPa (29,000 psi), and its viscosity near STP

5436-637: Is believed to have a mass of around 81 tonnes. It was the tallest temple in south India. Imperial Roman granite was quarried mainly in Egypt, and also in Turkey, and on the islands of Elba and Giglio . Granite became "an integral part of the Roman language of monumental architecture". The quarrying ceased around the third century AD. Beginning in Late Antiquity the granite was reused, which since at least

5587-434: Is called a binary or two-mica granite. Two-mica granites are typically high in potassium and low in plagioclase, and are usually S-type granites or A-type granites, as described below . Another aspect of granite classification is the ratios of metals that potentially form feldspars. Most granites have a composition such that almost all their aluminum and alkali metals (sodium and potassium) are combined as feldspar. This

5738-757: Is called the Rockall Bank , lying directly south from an area known as the Rockall Plateau. It is separated from the Outer Hebrides by the Rockall Trough , itself located within the Rockall Basin (also known as the "Hatton Rockall Basin"). In 1956 the British scientist James Fisher referred to the island as "the most isolated small rock in the oceans of the world". The neighbouring Hasselwood Rock and several other pinnacles of

5889-433: Is limited by the amount of thermal energy available, which must be replenished by crystallization of higher-melting minerals in the magma. Thus, the magma is melting crustal rock at its roof while simultaneously crystallizing at its base. This results in steady contamination with crustal material as the magma rises. This may not be evident in the major and minor element chemistry, since the minerals most likely to crystallize at

6040-508: Is not wholly accurate to describe all of them as gods in the medieval literature itself. He argues that the literary Tuath Dé are sui generis , and suggests "immortals" might be a more neutral term. Many of the Tuath Dé are not defined by singular qualities, but are more of the nature of well-rounded humans, who have areas of special interests or skills like the druidic arts they learned before traveling to Ireland. In this way, they do not correspond directly to other pantheons such as those of

6191-567: Is now discouraged. In 1975, a mineral new to science was discovered in a rock sample from Rockall. The mineral is called bazirite , named after the chemical elements barium and zirconium . Bazirite has the chemical formula BaZrSi 3 O 9 . Rockall forms part of the deeply eroded Rockall Igneous Centre that was formed as part of the North Atlantic Igneous Province . It was formed approximately 52 ± 8 million years ago based on rubidium–strontium dating , as part of

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6342-437: Is often washed over by large storm waves, particularly in winter. There is a small ledge of 3.5 by 1.3 m (11 ft 6 in by 4 ft 3 in), known as Hall's Ledge, four metres (13 ft) from the summit on the rock's western face. It is the only named geographical location on the rock. The nearest point on land from Rockall is 301.3 kilometres (162.7 nmi), east at the uninhabited Scottish island of Soay in

6493-413: Is one of the few pinnacles of the surrounding Helen's Reef ; it is located 301.3 kilometres (162.7 nautical miles) west of the uninhabited islet of Soay , St Kilda , Scotland, and 423.2 kilometres (263.0 statute miles; 228.5 nautical miles) northwest of Tory Island , County Donegal , Ireland. Its location was precisely determined by Nick Hancock during his 2014 expedition. The surrounding elevated seabed

6644-490: Is part of Na h-Eileanan Siar council area of Scotland . The exact position of Rockall and the size and shape of the Rockall Bank were first charted in 1831 by Captain A. T. E. Vidal , a Royal Navy surveyor. The first scientific expedition to Rockall was led by Miller Christy in 1896 when the Royal Irish Academy sponsored a study of the flora and fauna. They chartered the Granuaile . A detailed underwater mapping of

6795-404: Is permeated by sheets and channels of light granitic rock (the leucosome ). The leucosome is interpreted as partial melt of a parent rock that has begun to separate from the remaining solid residue (the melanosome). If enough partial melt is produced, it will separate from the source rock, become more highly evolved through fractional crystallization during its ascent toward the surface, and become

6946-454: Is relieved when overlying material is removed by erosion or other processes. Chemical weathering of granite occurs when dilute carbonic acid , and other acids present in rain and soil waters, alter feldspar in a process called hydrolysis . As demonstrated in the following reaction, this causes potassium feldspar to form kaolinite , with potassium ions, bicarbonate, and silica in solution as byproducts. An end product of granite weathering

7097-411: Is some concern that some granite sold as countertops or building material may be hazardous to health. Dan Steck of St. Johns University has stated that approximately 5% of all granite is of concern, with the caveat that only a tiny percentage of the tens of thousands of granite slab types have been tested. Resources from national geological survey organizations are accessible online to assist in assessing

7248-586: Is that it derives from the Gaelic Sgeir Rocail , meaning ' skerry of roaring' or 'sea rock of roaring' (although rocail can also be translated as 'tearing' or 'ripping'). The Dutch mapmakers Petrus Plancius and C. Claesz  [ nl ] , show an island called Rookol northwest of Ireland on their Map of New France and the Northern Atlantic Ocean (Amsterdam, c.  1594 ). The first literary reference to

7399-479: Is that magma will rise through the crust as a single mass through buoyancy . As it rises, it heats the wall rocks , causing them to behave as a power-law fluid and thus flow around the intrusion allowing it to pass without major heat loss. This is entirely feasible in the warm, ductile lower crust where rocks are easily deformed, but runs into problems in the upper crust which is far colder and more brittle. Rocks there do not deform so easily: for magma to rise as

7550-654: Is the Cailleach , said to have lived many lives that begin and end with her in stone formation. She is still celebrated at Ballycrovane Ogham Stone with offerings and the retelling of her life's stories. The tales of the Cailleach connect her to both land and sea. Several Otherworldly women are associated with sacred sites where seasonal festivals are held. They include Macha of Eamhain Mhacha , Carman , and Tailtiu , among others. Warrior goddesses are often depicted as

7701-410: Is the case when K 2 O + Na 2 O + CaO > Al 2 O 3 > K 2 O + Na 2 O. Such granites are described as normal or metaluminous . Granites in which there is not enough aluminum to combine with all the alkali oxides as feldspar (Al 2 O 3 < K 2 O + Na 2 O) are described as peralkaline , and they contain unusual sodium amphiboles such as riebeckite . Granites in which there

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7852-605: Is the oldest surviving manuscript written entirely in the Irish language; the early 12th-century Book of Leinster , which is in the Library of Trinity College Dublin ; and Bodleian Library, MS Rawlinson B 502 ( Rawl. ), which is in the Bodleian Library at the University of Oxford . Despite the dates of these sources, most of the material they contain predates their composition. Other important sources include

8003-489: Is typical of a larger family of granitic rocks , or granitoids , that are composed mostly of coarse-grained quartz and feldspars in varying proportions. These rocks are classified by the relative percentages of quartz, alkali feldspar, and plagioclase (the QAPF classification ), with true granite representing granitic rocks rich in quartz and alkali feldspar. Most granitic rocks also contain mica or amphibole minerals, though

8154-409: Is typically orthoclase or microcline and is often perthitic . The plagioclase is typically sodium-rich oligoclase . Phenocrysts are usually alkali feldspar. Granitic rocks are classified according to the QAPF diagram for coarse grained plutonic rocks and are named according to the percentage of quartz , alkali feldspar ( orthoclase , sanidine , or microcline ) and plagioclase feldspar on

8305-428: Is uncommon, is classified simply as quartz-rich granitoid or, if composed almost entirely of quartz, as quartzolite . True granites are further classified by the percentage of their total feldspar that is alkali feldspar. Granites whose feldspar is 65% to 90% alkali feldspar are syenogranites , while the feldspar in monzogranite is 35% to 65% alkali feldspar. A granite containing both muscovite and biotite micas

8456-622: The Dagda 's name is interpreted in medieval texts as "the good god". Nuada is cognate with the British god Nodens ; Lugh is a reflex of the pan- Celtic deity Lugus , the name of whom may indicate "Light"; Tuireann may be related to the Gaulish Taranis ; Ogma to Ogmios ; the Badb to Catubodua . The Ulster Cycle is traditionally set around the first century AD, and most of

8607-729: The Fomorians . Important works in the cycle are the Lebor Gabála Érenn ("Book of Invasions"), a legendary history of Ireland, the Cath Maige Tuired ("Battle of Moytura"), and the Aided Chlainne Lir (" Children of Lir "). The Ulster Cycle consists of heroic legends relating to the Ulaid , the most important of which is the epic Táin Bó Cúailnge ("Cattle Raid of Cooley"). The Fenian Cycle focuses on

8758-474: The Greeks or Romans . Irish goddesses or Otherworldly women are usually connected to the land, the waters, and sovereignty, and are often seen as the oldest ancestors of the people in the region or nation. They are maternal figures caring for the earth itself as well as their descendants, but also fierce defenders, teachers and warriors. The goddess Brigid is linked with poetry, healing, and smithing. Another

8909-461: The North Atlantic Igneous Province during the Paleogene . It is 301 kilometres (187 statute miles; 163 nautical miles) west of Soay, St Kilda , Scotland ; 423 kilometres (263 statute miles; 228 nautical miles) northwest of Tory Island , Ireland ; and 700 kilometres (430 statute miles; 380 nautical miles) south of Iceland . The nearest permanently inhabited place is North Uist , an island in

9060-727: The Outer Hebrides of Scotland, 370 kilometres (230 mi; 200 nmi) to the east. The United Kingdom claimed Rockall in 1955 and incorporated it as a part of Scotland in 1972. The UK does not make a claim to an extended exclusive economic zone (EEZ) based on Rockall, as it has ratified the United Nations Convention on the Law of the Sea (UNCLOS), which says that "rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf". However, such features are entitled to

9211-701: The St Kilda archipelago. The nearest inhabited area lies 303.2 kilometres (163.7 nmi) east at Hirta , the largest island in the St. Kilda group, which is populated intermittently at a single military base. The nearest permanently inhabited settlement is 366.8 km (198.1 nmi) west of the headland of Aird an Rùnair , near the crofting township of Hogha Gearraidh on the island of North Uist at NF705711 ( 57°36′33″N 7°31′7″W  /  57.60917°N 7.51861°W  / 57.60917; -7.51861  ( Hogha Gearraidh / Hougharry ) ) . North Uist

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9362-514: The Togail Troí , an Irish adaptation of Dares Phrygius ' De excidio Troiae historia , found in the Book of Leinster. They also argue that the material culture depicted in the stories is generally closer to that of the time of their composition than to that of the distant past. The Mythological Cycle , comprising stories of the former gods and origins of the Irish, is the least well preserved of

9513-421: The bards of nobility. Once the noble houses started to decline, this tradition was put to an abrupt end. The bards passed the stories to their families, and the families would take on the oral tradition of storytelling. During the first few years of the 20th century, Herminie Templeton Kavanagh wrote down many Irish folk tales, which she published in magazines and in two books. Twenty-six years after her death,

9664-571: The A-Q-P half of the diagram. True granite (according to modern petrologic convention) contains between 20% and 60% quartz by volume, with 35% to 90% of the total feldspar consisting of alkali feldspar . Granitic rocks poorer in quartz are classified as syenites or monzonites , while granitic rocks dominated by plagioclase are classified as granodiorites or tonalites . Granitic rocks with over 90% alkali feldspar are classified as alkali feldspar granites . Granitic rock with more than 60% quartz, which

9815-514: The Admiralty hand it back. It's no' theirs." The British Government ignored the protest. In 1971, Captain T. R. Kirkpatrick RE led the landing party on a government expedition named "Operation Top Hat" that was mounted from RFA  Engadine to establish that the rock was part of the United Kingdom and to prepare the islet for the installation of a light beacon. The landing party included Royal Engineers, Royal Marines and civilian members from

9966-571: The British Crown when Lieutenant-Commander Desmond Scott RN , Sergeant Brian Peel RM , Corporal AA Fraser RM, and James Fisher (a civilian naturalist and former Royal Marine), were winched onto the island by a Royal Navy helicopter from HMS  Vidal (coincidentally named after the man who first charted the island). The annexation of Rockall was announced by the Admiralty on 21 September 1955. The expedition team cemented in

10117-529: The Cycle of the Kings, or more correctly Cycles, as there are a number of independent groupings. This term is a more recent addition to the cycles, with it being coined in 1946 by Irish literary critic Myles Dillon . The kings that are included range from the almost entirely mythological Labraid Loingsech , who allegedly became High King of Ireland around 431 BC, to the entirely historical Brian Boru . However,

10268-615: The European Union safety standards (section 4.1.1.1 of the National Health and Engineering study) and radon emission levels well below the average outdoor radon concentrations in the US. Granite and related marble industries are considered one of the oldest industries in the world, existing as far back as Ancient Egypt . Major modern exporters of granite include China, India, Italy, Brazil, Canada, Germany, Sweden, Spain and

10419-637: The Fianna Cycle is the Acallam na Senórach ( Colloquy of the Old Men ), which is found in two 15th century manuscripts, the Book of Lismore and Laud 610, as well as a 17th century manuscript from Killiney , County Dublin . The text is dated from linguistic evidence to the 12th century. The text records conversations between Caílte mac Rónáin and Oisín , the last surviving members of

10570-596: The Fianna, and Saint Patrick , and consists of about 8,000 lines. The late dates of the manuscripts may reflect a longer oral tradition for the Fenian stories. The Fianna of the story are divided into the Clann Baiscne, led by Fionn mac Cumhaill (often rendered as "Finn MacCool", Finn Son of Cumhall), and the Clann Morna, led by his enemy, Goll mac Morna . Goll killed Fionn's father, Cumhal , in battle and

10721-682: The Fomorians in the Battle of Mag Tuired . This has been likened to other Indo-European myths of a war between gods, such as the Æsir and Vanir in Norse mythology and the Olympians and Titans in Greek mythology . Heroes in Irish mythology can be found in two distinct groups. There is the lawful hero who exists within the boundaries of the community, protecting their people from outsiders. Within

10872-635: The Gaelic-speaking community in Scotland and there are many extant texts from that country. They also differ from the Ulster Cycle in that the stories are told mainly in verse and that in tone they are nearer to the tradition of romance than the tradition of epic. The stories concern the doings of Fionn mac Cumhaill and his band of soldiers, the Fianna . The single most important source for

11023-712: The Institute of Geological Sciences in London. The party was landed by winch line from the Wessex 5 helicopters of the Royal Naval Air Services Commando Headquarters Squadron, commanded by Lt Cmdr Neil Foster RN. As well as collecting samples of the aegirine granite, "rockallite", for later analysis in London, the top of the rock was blown off using a newly developed blasting technique, precision pre-splitting. This created

11174-613: The Long Way Round Circumnavigation of Ireland via Rockall island. The Barracuda-style naval patrol, search and rescue vessel, Thunder Child , completed the route in 34 hours, 1 minute, and 47 seconds. Set in an anti-clockwise direction, the new record – the first of its kind – is now subject to ratification by Irish Sailing and the Union Internationale Motonautique , the world governing board for all powerboat activity. Rockall

11325-561: The Mythological Cycle represents a Golden Age, the Ulster Cycle is Ireland's Heroic Age . Like the Ulster Cycle, the Fianna Cycle or Fenian Cycle, also referred to as the Ossianic Cycle, is concerned with the deeds of Irish heroes. The stories of the Cycle appear to be set around the 3rd century and mainly in the provinces of Leinster and Munster . They differ from the other cycles in the strength of their links with

11476-455: The Tuath Dé were Christians. Sometimes they explained the Tuath Dé as fallen angels ; neutral angels who sided neither with God nor Lucifer and were punished by being forced to dwell on the Earth; or ancient humans who had become highly skilled in magic. However, several writers acknowledged that at least some of them had been gods. There is strong evidence that many of the Tuath Dé represent

11627-599: The Tuatha Dé Danann were defeated by the Milesians. By the Middle Ages, the Tuatha Dé Danann were not viewed so much as gods as the shape-shifting magician population of an earlier Golden Age Ireland. Texts such as Lebor Gabála Érenn and Cath Maige Tuireadh present them as kings and heroes of the distant past, complete with death-tales. However, there is considerable evidence, both in the texts and from

11778-492: The Ulster Cycle is the Táin Bó Cúailnge . Other important Ulster Cycle tales include The Tragic Death of Aife's only Son , Bricriu's Feast , and The Destruction of Da Derga's Hostel . The Exile of the Sons of Usnach , better known as the tragedy of Deirdre and the source of plays by John Millington Synge , William Butler Yeats , and Vincent Woods , is also part of this cycle. This cycle is, in some respects, close to

11929-511: The United States. The Red Pyramid of Egypt ( c.  2590 BC ), named for the light crimson hue of its exposed limestone surfaces, is the third largest of Egyptian pyramids . Pyramid of Menkaure , likely dating 2510 BC, was constructed of limestone and granite blocks. The Great Pyramid of Giza (c. 2580 BC ) contains a huge granite sarcophagus fashioned of "Red Aswan Granite". The mostly ruined Black Pyramid dating from

12080-515: The Wooing Of Étain and Cath Maige Tuireadh , the (second) Battle of Magh Tuireadh . One of the best known of all Irish stories, Oidheadh Clainne Lir , or The Tragedy of the Children of Lir , is also part of this cycle. Lebor Gabála Érenn is a pseudo-history of Ireland, tracing the ancestry of the Irish back to before Noah . It tells of a series of invasions or "takings" of Ireland by

12231-639: The action takes place in the provinces of Ulster and Connacht . It consists of a group of heroic tales dealing with the lives of Conchobar mac Nessa , king of Ulster, the great hero Cú Chulainn , who was the son of Lug ( Lugh ), and of their friends, lovers, and enemies. These are the Ulaid , or people of the North-Eastern corner of Ireland and the action of the stories centres round the royal court at Emain Macha (known in English as Navan Fort), close to

12382-624: The adjacent seabed or to fishing rights in the surrounding seas. The origin and meaning of the islet's name Rockall is uncertain. The Scottish Gaelic name for the islet, Ròcal , may derive from an Old Norse name that may contain the element fjall , meaning 'mountain'. Coates has suggested that the name is from the Norse * rok , meaning 'foaming sea', and kollr , meaning 'bald head'—a word which appears in other placenames in Scandinavian-speaking areas. Another idea

12533-424: The area around Rockall undertaken in 2011–2012 by Marine Scotland showed that Rockall itself is a minor pinnacle, whilst Helen's Reef extends in a sweeping arc of fissures and ridges to the north-west of the islet. Between the islet and Helen's Reef is a deeper trench much used by squid fishermen. Rockall is located in the pathway of the warming and moderating Gulf Stream . Although the rock has no weather station,

12684-505: The arrival of the Gaels, the Tuatha Dé Danann retired underground to become the fairy people of later myth and legend. The Metrical Dindshenchas is the great onomastics work of early Ireland, giving the naming legends of significant places in a sequence of poems. It includes a lot of important information on Mythological Cycle figures and stories, including the Battle of Tailtiu, in which

12835-419: The base of the chamber are the same ones that would crystallize anyway, but crustal assimilation is detectable in isotope ratios. Heat loss to the country rock means that ascent by assimilation is limited to distance similar to the height of the magma chamber. Physical weathering occurs on a large scale in the form of exfoliation joints , which are the result of granite's expanding and fracturing as pressure

12986-418: The big difference in rheology between mafic and felsic magmas makes this process problematic in nature. Granitization is an old, and largely discounted, hypothesis that granite is formed in place through extreme metasomatism . The idea behind granitization was that fluids would supposedly bring in elements such as potassium, and remove others, such as calcium, to transform a metamorphic rock into granite. This

13137-610: The boy Fionn was brought up in secrecy. As a youth, while being trained in the art of poetry, he accidentally burned his thumb while cooking the Salmon of Knowledge, which allowed him to suck or bite his thumb to receive bursts of stupendous wisdom. He took his place as the leader of his band and numerous tales are told of their adventures. Two of the greatest of the Irish tales, Tóraigheacht Dhiarmada agus Ghráinne ( The Pursuit of Diarmuid and Gráinne ) and Oisín in Tír na nÓg form part of

13288-642: The breakup of Laurasia . Greenland and Europe separated and the northeast Atlantic Ocean was formed between them, eventually leaving Rockall as an isolated islet. The RV Celtic Explorer surveyed the Rockall Bank in 2003. The Irish Light Vessel Granuaile (the same name as the steamer on the RIA 1896 botany survey) was chartered by the Geological Survey of Ireland , on behalf of the Department of Communications, Marine and Natural Resources , to conduct

13439-425: The cycle. The Diarmuid and Grainne story, which is one of the cycle's few prose tales, is a probable source of Tristan and Iseult . The world of the Fianna Cycle is one in which professional warriors spend their time hunting, fighting, and engaging in adventures in the spirit world. New entrants into the band are expected to be knowledgeable in poetry as well as undergo a number of physical tests or ordeals. Most of

13590-542: The cycles; these include the echtrai tales of journeys to the Otherworld (such as The Voyage of Bran ), and the Dindsenchas ("lore of places"). Some written materials have not survived, and many more myths were likely never written down. The main supernatural beings in Irish mythology are the Tuatha Dé Danann ("the folk of the goddess Danu"), also known by the earlier name Tuath Dé ("god folk" or "tribe of

13741-404: The division between S-type (produced by underplating) and I-type (produced by injection and differentiation) granites, discussed below. The composition and origin of any magma that differentiates into granite leave certain petrological evidence as to what the granite's parental rock was. The final texture and composition of a granite are generally distinctive as to its parental rock. For instance,

13892-600: The earliest known version of the Táin Bó Cúailnge ("The Cattle Raid of Cooley"). This is one of Europe's oldest epics written in a vernacular language. Other 15th-century manuscripts, such as The Book of Fermoy , also contain interesting materials, as do such later syncretic works such as Geoffrey Keating 's Foras Feasa ar Éirinn ( The History of Ireland ) ( c.  1640 ). These later compilers and writers may well have had access to manuscript sources that have since disappeared. Most of these manuscripts were created by Christian monks , who may well have been torn between

14043-413: The early 16th century became known as spolia . Through the process of case-hardening , granite becomes harder with age. The technology required to make tempered metal chisels was largely forgotten during the Middle Ages. As a result, Medieval stoneworkers were forced to use saws or emery to shorten ancient columns or hack them into discs. Giorgio Vasari noted in the 16th century that granite in quarries

14194-478: The exploits of the mythical hero Finn and his warrior band the Fianna , including the lengthy Acallam na Senórach ("Tales of the Elders"). The Cycles of the Kings comprises legends about historical and semi-historical kings of Ireland (such as Buile Shuibhne , "The Madness of King Sweeny"), and tales about the origins of dynasties and peoples. There are also mythological texts that do not fit into any of

14345-588: The finish of the 2011–12 Volvo Ocean Race around the world. The 2015–2016 Clipper Round the World Yacht Race race 12 from New York to Derry was extended around Rockall despite previous promises to crew from Sir Robin Knox-Johnston that this would not happen again after the race to Danang. In July, 2022, the 2019–2020 Clipper Round the world race (delayed for 2 years by COVID) was again extended on Leg 8 to go around Rockall before completing

14496-579: The first magma to enter solidifies and provides a form of insulation for later magma. These mechanisms can operate in tandem. For example, diapirs may continue to rise through the brittle upper crust through stoping , where the granite cracks the roof rocks, removing blocks of the overlying crust which then sink to the bottom of the diapir while the magma rises to take their place. This can occur as piecemeal stopping (stoping of small blocks of chamber roof), as cauldron subsidence (collapse of large blocks of chamber roof), or as roof foundering (complete collapse of

14647-762: The four cycles. It is about the principal people who invaded and inhabited the island. The people include Cessair and her followers, the Formorians, the Partholinians, the Nemedians, the Firbolgs, the Tuatha Dé Danann , and the Milesians. The most important sources are the Metrical Dindshenchas or Lore of Places and the Lebor Gabála Érenn or Book of Invasions . Other manuscripts preserve such mythological tales as The Dream of Aengus ,

14798-473: The gods of Irish paganism . The name itself means "tribe of gods", and the ninth-century Scél Tuain meic Cairill (Tale of Tuan mac Cairill ) speaks of the Tuath Dé ocus Andé , "tribe of gods and un-gods". Goibniu, Credne and Luchta are called the trí dé dáno , "three gods of craft". In Sanas Cormaic ( Cormac's Glossary), Anu is called "mother of the Irish gods", Nét a "god of war", and Brigid

14949-469: The gods"). Early medieval Irish writers also called them the fir dé (god-men) and cenéla dé (god-kindreds), possibly to avoid calling them simply 'gods'. They are often depicted as kings, queens, bards, warriors, heroes, healers and craftsmen who have supernatural powers and are immortal. Prominent members include The Dagda ("the great god"); The Morrígan ("the great queen" or "phantom queen"); Lugh ; Nuada ; Aengus ; Brigid ; Manannán ; Dian Cécht

15100-550: The greatest glory of the Kings' Cycle is the Buile Shuibhne ( The Frenzy of Sweeney ), a 12th century tale told in verse and prose. Suibhne, king of Dál nAraidi , was cursed by St. Ronan and became a kind of half-man, half bird, condemned to live out his life in the woods, fleeing from his human companions. The story has captured the imaginations of contemporary Irish poets and has been translated by Trevor Joyce and Seamus Heaney . The adventures, or echtrae , are

15251-713: The grotto is a highly regarded piece of Buddhist art , and along with the temple complex to which it belongs, Seokguram was added to the UNESCO World Heritage List in 1995. Rajaraja Chola I of the Chola Dynasty in South India built the world's first temple entirely of granite in the 11th century AD in Tanjore , India . The Brihadeeswarar Temple dedicated to Lord Shiva was built in 1010. The massive Gopuram (ornate, upper section of shrine)

15402-594: The healer; and Goibniu the smith. They are also said to control the fertility of the land; the tale De Gabáil in t-Sída says the first Gaels had to establish friendship with the Tuath Dé before they could raise crops and herds. They dwell in the Otherworld but interact with humans and the human world. Many are associated with specific places in the landscape, especially the sídhe : prominent ancient burial mounds such as Brú na Bóinne , which are entrances to Otherworld realms. The Tuath Dé can hide themselves with

15553-674: The iconography of the Gundestrup Cauldron . However, these "nativist" claims have been challenged by "revisionist" scholars who believe that much of the literature was created, rather than merely recorded, in Christian times, more or less in imitation of the epics of classical literature that came with Latin learning. The revisionists point to passages apparently influenced by the Iliad in Táin Bó Cuailnge , and to

15704-779: The incorporation of the island into the District of Harris in the County of Inverness under the Island of Rockall Act 1972 . It would have reinforced the UK Government's claim with regard to seabed rights in the area at the time. In 1978, eight members of the Dangerous Sports Club , including David Kirke , one of its founders, held a cocktail party on the island, allegedly leaving with the plaque. Former SAS member and survival expert Tom McClean decided to live on

15855-449: The island from 26 May 1985 to 4 July 1985 to affirm the UK's claim to the islet. In 1997, three members of the environmentalist organisation Greenpeace occupied the islet for 42 days, calling it Waveland , to protest against oil exploration . Greenpeace declared the island to be a "new Global State" (as a spoof micronation ) and offered citizenship to anyone willing to take their pledge of allegiance. The British Government's response

16006-570: The island, which is called Rokol , is found in Martin Martin 's A Late Voyage to St. Kilda , published in 1698. This book gives an account of a voyage to the archipelago of St Kilda , and Martin states: "... and from it lies Rokol, a small rock sixty leagues [300 km] to the westward of St Kilda; the inhabitants of this place call it Rokabarra ." The name Rocabarraigh is also used in Scottish Gaelic folklore for

16157-480: The islet, having landed for the first time the previous year on a reconnaissance expedition which coincided with Queen Elizabeth II 's Diamond Jubilee. The weather conditions at the time "were not favourable" according to a Maritime and Coastguard Agency official. Subsequently, Hancock postponed his challenge until 2014. On 5 June 2014 Hancock landed on Rockall to begin his 60-day survival attempt. Despite being forced to cut his 60-day goal short after losing supplies in

16308-451: The isolated position makes for an extreme maritime climate without heat or cold extremes. Rockall is made of a type of peralkaline granite that is relatively rich in sodium and potassium . Within this granite are darker bands richer in iron because they contain two iron-sodium silicate minerals called aegirine and riebeckite . The darker bands are a type of granite that geologists have named " rockallite ", although use of this term

16459-429: The kin-group or tuath , heroes are human and gods are not. The Fianna warrior bands are seen as outsiders, connected with the wilderness, youth, and liminal states. Their leader was called Fionn mac Cumhaill, and the first stories of him are told in fourth century. They are considered aristocrats and outsiders who protect the community from other outsiders; though they may winter with a settled community, they spend

16610-468: The later Voyage of St. Brendan . While not as ancient, later 8th century AD works, that influenced European literature, include The Vision of Adamnán . Although there are no written sources of Irish mythology, many stories are passed down orally through traditional storytelling. Some of these stories have been lost, but some Celtic regions continue to tell folktales to the modern-day. Folktales and stories were primarily preserved by monastic scribes from

16761-748: The leg at the mouth of the River Foyle in Ireland. The fleet had crossed the Atlantic in record time, and the City docks in Derry had no room for the fleet of 11 boats to berth. The race organizers sent the fleet around Rockall in order to extend the leg by approximately one day's sailing time to clear the docks in Derry. In 2017, the Safehaven Marine team led by Frank Kowalski set a world record for

16912-402: The local authority for Rockall, approved planning permission for the plaque. The 2010 expedition was cancelled, and Strangeway did not replace the plaque. In October 2011 a group of amateur radio operators from Belgium travelled by ship to Rockall. Several of them climbed up the rocks and set up a radio station for some hours. They stayed overnight on top of the island. Radio contacts to all over

17063-474: The lower crust , rather than by decompression of mantle rock, as is the case with basaltic magmas. It has also been suggested that some granites found at convergent boundaries between tectonic plates , where oceanic crust subducts below continental crust, were formed from sediments subducted with the oceanic plate. The melted sediments would have produced magma intermediate in its silica content, which became further enriched in silica as it rose through

17214-729: The lower continental crust at high thermal gradients. This leads to significant extraction of hydrous felsic melts from granulite-facies resitites. A-type granites occur in the Koettlitz Glacier Alkaline Province in the Royal Society Range, Antarctica. The rhyolites of the Yellowstone Caldera are examples of volcanic equivalents of A-type granite. M-type granite was later proposed to cover those granites that were clearly sourced from crystallized mafic magmas, generally sourced from

17365-435: The magma is inevitable once enough magma has accumulated. However, the question of precisely how such large quantities of magma are able to shove aside country rock to make room for themselves (the room problem ) is still a matter of research. Two main mechanisms are thought to be important: Of these two mechanisms, Stokes diapirism has been favoured for many years in the absence of a reasonable alternative. The basic idea

17516-426: The magma. Other processes must produce these great volumes of felsic magma. One such process is injection of basaltic magma into the lower crust, followed by differentiation, which leaves any cumulates in the mantle. Another is heating of the lower crust by underplating basaltic magma, which produces felsic magma directly from crustal rock. The two processes produce different kinds of granites, which may be reflected in

17667-408: The magmatic parent of granitic rock. The residue of the source rock becomes a granulite . The partial melting of solid rocks requires high temperatures and the addition of water or other volatiles which lower the solidus temperature (temperature at which partial melting commences) of these rocks. It was long debated whether crustal thickening in orogens (mountain belts along convergent boundaries )

17818-405: The mantle. Although the fractional crystallisation of basaltic melts can yield small amounts of granites, which are sometimes found in island arcs, such granites must occur together with large amounts of basaltic rocks. H-type granites were suggested for hybrid granites, which were hypothesized to form by mixing between mafic and felsic from different sources, such as M-type and S-type. However,

17969-525: The modern town of Armagh . The Ulaid had close links with the Irish colony in Scotland , and part of Cú Chulainn's training takes place in that colony. The cycle consists of stories of the births, early lives and training, wooing, battles, feastings, and deaths of the heroes. It also reflects a warrior society in which warfare consists mainly of single combats and wealth is measured mainly in cattle. These stories are written mainly in prose. The centerpiece of

18120-467: The moon than have landed on Rockall" The earliest recorded date of landing on the island is often given as 8 July 1810, when a Royal Navy officer named Basil Hall led a small landing party from the frigate HMS  Endymion to the summit. However, research by James Fisher (see below), in the log of Endymion and elsewhere, indicates that the actual date for this first landing was on Sunday 8 September 1811. The landing party left Endymion for

18271-410: The mythological cycle. Some of the characters from the latter reappear, and the same sort of shape-shifting magic is much in evidence, side by side with a grim, almost callous realism. While we may suspect a few characters, such as Medb or Cú Roí , of once being deities, and Cú Chulainn in particular displays superhuman prowess, the characters are mortal and associated with a specific time and place. If

18422-550: The native Irish gods with their homes in burial mounds. The third group are the gods that dwell in the sea and the fourth group includes stories of the Otherworld. The gods that appear most often are the Dagda and Lugh. Some scholars have argued that the stories of these gods align with Greek stories and gods. The Fomorians or Fomori ( Old Irish : Fomóire ) are a supernatural race, who are often portrayed as hostile and monstrous beings. Originally, they were said to come from under

18573-441: The overlying crust. Early fractional crystallisation serves to reduce a melt in magnesium and chromium, and enrich the melt in iron, sodium, potassium, aluminum, and silicon. Further fractionation reduces the content of iron, calcium, and titanium. This is reflected in the high content of alkali feldspar and quartz in granite. The presence of granitic rock in island arcs shows that fractional crystallization alone can convert

18724-437: The poems are attributed to being composed by Oisín . This cycle creates a bridge between pre-Christian and Christian times. It was part of the duty of the medieval Irish bards, or court poets , to record the history of the family and the genealogy of the king they served. This they did in poems that blended the mythological and the historical to a greater or lesser degree. The resulting stories from what has come to be known as

18875-736: The reign of Amenemhat III once had a polished granite pyramidion or capstone, which is now on display in the main hall of the Egyptian Museum in Cairo (see Dahshur ). Other uses in Ancient Egypt include columns , door lintels , sills , jambs , and wall and floor veneer. How the Egyptians worked the solid granite is still a matter of debate. Tool marks described by the Egyptologist Anna Serotta indicate

19026-564: The risk factors in granite country and design rules relating, in particular, to preventing accumulation of radon gas in enclosed basements and dwellings. A study of granite countertops was done (initiated and paid for by the Marble Institute of America) in November 2008 by National Health and Engineering Inc. of USA. In this test, all of the 39 full-size granite slabs that were measured for the study showed radiation levels well below

19177-403: The rock by boat. Whilst there, Endymion , which was taking depth measurements around Rockall, lost visual contact with the rock as a haze descended. The ship drifted away, leaving the landing party stranded. The expedition made a brief attempt to return to the ship, but could not find the frigate in the haze, and soon gave up and returned to Rockall. After the haze became a fog, the lookout sent to

19328-418: The rock's high quartz content and dearth of available bases, with the base-poor status predisposing the soil to acidification and podzolization in cool humid climates as the weather-resistant quartz yields much sand. Feldspars also weather slowly in cool climes, allowing sand to dominate the fine-earth fraction. In warm humid regions, the weathering of feldspar as described above is accelerated so as to allow

19479-414: The rocks often bear a close resemblance. Under these conditions, granitic melts can be produced in place through the partial melting of metamorphic rocks by extracting melt-mobile elements such as potassium and silicon into the melts but leaving others such as calcium and iron in granulite residues. This may be the origin of migmatites . A migmatite consists of dark, refractory rock (the melanosome ) that

19630-492: The roof of a shallow magma chamber accompanied by a caldera eruption.) There is evidence for cauldron subsidence at the Mt. Ascutney intrusion in eastern Vermont. Evidence for piecemeal stoping is found in intrusions that are rimmed with igneous breccia containing fragments of country rock. Assimilation is another mechanism of ascent, where the granite melts its way up into the crust and removes overlying material in this way. This

19781-538: The sea or the earth. Later, they were portrayed as sea raiders, which was probably influenced by the Viking raids on Ireland around that time. Later still they were portrayed as giants. They are enemies of Ireland's first settlers and opponents of the Tuatha Dé Danann, although some members of the two races have offspring. The Fomorians were viewed as the alter-egos to the Tuath Dé The Tuath Dé defeat

19932-496: The summer is calm with no storm waves washing over the rock. In total there have been just over twenty species of seabird and six other animal species observed (including the aforementioned molluscs) on or near the islet. Cold-water coral biogenic reefs have been identified on the wider Rockall Bank, which are contributing features for the East Rockall Bank and North-West Rockall Bank SACs . Granite Granite

20083-535: The summers living wild, training adolescents and providing a space for war-damaged veterans. The time of vagrancy for these youths is designated as a transition in life post puberty but pre-manhood. Manhood being identified as owning or inheriting property. They live under the authority of their own leaders, or may be somewhat anarchic, and may follow other deities or spirits than the settled communities. The church refused to recognize this group as an institution and referred to them as "sons of death". The Oilliphéist

20234-435: The surface than magmas of I-type granites, which are thus more common as volcanic rock (rhyolite). They are also orogenic but range from metaluminous to strongly peraluminous. Although both I- and S-type granites are orogenic, I-type granites are more common close to the convergent boundary than S-type. This is attributed to thicker crust further from the boundary, which results in more crustal melting. A-type granites show

20385-439: The surrounding Helen's Reef are smaller, at half the size of Rockall or less, and equally remote, but those formations are legally not islands or points on land, as they are often submerged completely, only revealed momentarily above certain types of ocean surface waves . Rockall is about 25 metres (80 ft) wide and 31 m (102 ft) long at its base and rises sheer to a height of 17.15 m (56 ft 3 in). It

20536-597: The test. Consequently, in April 1955 an order was issued to the Admiralty to seize the island and declare UK sovereignty, lest it become an outpost for foreign observers. On 7 November 1955, J. Abrach Mackay, an 84-year- old local councillor and member of the Clan Mackay , made a protest about the annexation; he declared: "My old father, God rest his soul, claimed that island for the Clan of Mackay in 1846 and I now demand that

20687-440: The texture is known as porphyritic . A granitic rock with a porphyritic texture is known as a granite porphyry . Granitoid is a general, descriptive field term for lighter-colored, coarse-grained igneous rocks. Petrographic examination is required for identification of specific types of granitoids. Granites can be predominantly white, pink, or gray in color, depending on their mineralogy . The alkali feldspar in granites

20838-433: The top of Rockall spotted the ship again, but it turned away from Rockall before the expedition in their boats reached it. Finally, just before sunset, the frigate was again spotted from the top of Rockall, and the expedition was able to get back on board. The crew of Endymion reported that they had been searching for five or six hours, firing their cannon every ten minutes. Hall related this experience and other adventures in

20989-502: The uranium washes into the sediments from the granite uplands and associated, often highly radioactive pegmatites. Cellars and basements built into soils over granite can become a trap for radon gas, which is formed by the decay of uranium. Radon gas poses significant health concerns and is the number two cause of lung cancer in the US behind smoking. Thorium occurs in all granites. Conway granite has been noted for its relatively high thorium concentration of 56±6 ppm. There

21140-617: The use of flint tools on finer work with harder stones, e.g. when producing the hieroglyphic inscriptions. Patrick Hunt has postulated that the Egyptians used emery , which has greater hardness. The Seokguram Grotto in Korea is a Buddhist shrine and part of the Bulguksa temple complex. Completed in 774 AD, it is an artificial grotto constructed entirely of granite. The main Buddha of

21291-618: The wider Celtic world, that they were once considered deities . Even after they are displaced as the rulers of Ireland, characters such as Lugh , the Mórrígan , Aengus and Manannán Mac Lir appear in stories set centuries later, betraying their immortality. A poem in the Book of Leinster lists many of the Tuatha Dé, but ends "Although [the author] enumerates them, he does not worship them". Goibniu , Creidhne and Luchta are referred to as Trí Dé Dána ("three gods of craftsmanship"), and

21442-536: The women who trained the hero Fionn mac Cumhaill . Zoomorphism is an important feature. Badb Catha, for instance, is "the Raven of Battle", and in the Táin Bó Cúailnge , The Morrígan shapeshifts into an eel, a wolf, and a cow. Irish gods are divided into four main groups. Group one encompasses the older gods of Gaul and Britain. The second group is the main focus of much of the mythology and surrounds

21593-568: The wonders seen on them that may have resulted from the combination of the experiences of fishermen combined and the Other World elements that inform the adventures. Of the seven immrama mentioned in the manuscripts, only three have survived: The Voyage of Máel Dúin , the Voyage of the Uí Chorra , and the Voyage of Snedgus and Mac Riagla . The Voyage of Mael Duin is the forerunner of

21744-426: The world were made using HF frequencies under the call sign "MM0RAI/P". In 2013 an occupation of the island by explorer Nick Hancock to raise money for the charity Help for Heroes was planned. The challenge was to land on Rockall and survive solo for 60 days. On 31 May 2013, Hancock, and a TV crew from BBC's The One Show , sailed to the islet aboard Orca III , and he unsuccessfully attempted to land and survive on

21895-409: Was "far softer and easier to work than after it has lain exposed" while ancient columns, because of their "hardness and solidity have nothing to fear from fire or sword, and time itself, that drives everything to ruin, not only has not destroyed them but has not even altered their colour." Irish mythology Irish mythology is the body of myths indigenous to the island of Ireland . It

22046-519: Was also a tendency to rework Irish genealogies to fit them into the schemas of Greek or biblical genealogy. Whether medieval Irish literature provides reliable evidence of oral tradition remains a matter for debate. Kenneth Jackson described the Ulster Cycle as a "window on the Iron Age", and Garret Olmsted has attempted to draw parallels between Táin Bó Cuailnge , the Ulster Cycle epic and

22197-481: Was originally passed down orally in the prehistoric era . In the early medieval era , some myths were transcribed by Christian monks , who heavily altered and Christianised the myths. Irish mythology is the best-preserved branch of Celtic mythology . The myths are conventionally grouped into ' cycles '. The Mythological Cycle consists of tales and poems about the god-like Tuatha Dé Danann , who are based on Ireland's pagan deities, and other mythical races like

22348-405: Was sufficient to produce granite melts by radiogenic heating , but recent work suggests that this is not a viable mechanism. In-situ granitization requires heating by the asthenospheric mantle or by underplating with mantle-derived magmas. Granite magmas have a density of 2.4 Mg/m , much less than the 2.8 Mg/m of high-grade metamorphic rock. This gives them tremendous buoyancy, so that ascent of

22499-564: Was supposed to occur across a migrating front. However, experimental work had established by the 1960s that granites were of igneous origin. The mineralogical and chemical features of granite can be explained only by crystal-liquid phase relations, showing that there must have been at least enough melting to mobilize the magma. However, at sufficiently deep crustal levels, the distinction between metamorphism and crustal melting itself becomes vague. Conditions for crystallization of liquid magma are close enough to those of high-grade metamorphism that

22650-612: Was the final territorial expansion of the British empire. The initial incentive for the annexation was the test-firing of the UK's first guided nuclear weapon , the American-made Corporal missile . The missile was to be launched from South Uist and sent over the North Atlantic. The Ministry of Defence was concerned that the unclaimed island would provide an opportunity for the Soviet Union to spy on

22801-401: Was to state that "Rockall is British territory. It is part of Scotland and anyone is free to go there and can stay as long as they please" and otherwise ignore them. The 1955 plaque was unscrewed and refixed back to front, and subsequently it disappeared. In June 2005 the first amateur radio (ham radio) activation of Rockall took place when the club station MS0IRC/P was set up and operated for

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