Wicklow Mountains
The Wicklow Mountains form the largest continuous upland area in Ireland. They occupy the whole centre of County Wicklow and stretch outside its borders into the counties of Dublin, Wexford and Carlow. Where the mountains extend into County Dublin, they are known locally as the Dublin Mountains. The highest peak is Lugnaquilla at.
The mountains are primarily composed of granite surrounded by an envelope of mica-schist and much older rocks such as quartzite. They were pushed up during the Caledonian orogeny at the start of the Devonian period and form part of the Leinster Chain, the largest continuous area of granite in Ireland and Britain. The mountains owe much of their present topography to the effects of the last ice age, which deepened the glens and created corrie and ribbon lakes. Copper and lead have been the main metals mined in the mountains and a brief gold rush occurred in the 18th century.
Several major river systems have their source in the mountains, such as the Liffey, Dargle, Slaney and Avoca rivers. Powerscourt Waterfall is the second tallest in Ireland at. A number of these rivers have been harnessed to create reservoirs for drinking water for Dublin and its surroundings.
The Wicklow Mountains experience a temperate oceanic climate with mild, damp summers and cool, wet winters. The dominant habitat of the uplands consists of blanket bog, heath and upland grassland. The uplands support a number of bird species, including merlin and peregrine falcon. The valleys are a mixture of coniferous and deciduous woodland.
The mountains have been inhabited since Neolithic times and a number of typical monuments, in particular a series of passage tombs, survive to the present day. The monastery at Glendalough, founded in the late 6th century by Saint Kevin, was an important centre of the Early Church in Ireland. Following the Norman invasion in the 12th century, the Wicklow Mountains became a stronghold and hiding place for Irish clans opposed to English rule. The O'Byrne and O'Toole families carried out a campaign of harassment against the settlers for almost five centuries. Later the mountains harboured rebels during the 1798 Rising. Rebel activity died out after the construction of the Wicklow Military Road at the start of the 19th century and the mountains began to attract tourists to the ruins at Glendalough and to admire the mountain scenery.
The Wicklow Mountains continue to be a major attraction for tourism and recreation. The entire upland area is designated as a Special Area of Conservation and as a Special Protection Area under European Union law. The Wicklow Mountains National Park was established in 1991 to conserve the local biodiversity and landscape.
Name
The Wicklow Mountains take their name from County Wicklow which in turn takes its name from Wicklow town. The origin of the name is from the Old Norse Wykynglo or Wykinlo. The Irish name for Wicklow, Cill Mhantáin, means "Church of Mantan", named after an apostle of Saint Patrick. Wicklow was not established as a county until 1606; before that it had been part of County Dublin. During the medieval period, prior to the establishment of County Wicklow, the English administration in Dublin referred to the region as the Leinster Mountains.An early name for the whole area of the Wicklow Mountains was Cualu, later Cuala. The Irish name for Great Sugar Loaf mountain is Ó Cualann. There are also historic names for various territories in the mountains held by local clans: the north part of Wicklow and south Dublin was known as Cualann or Fir Chualann, anglicised 'Fercullen', while the Glen of Imaal takes its name from the territory of Uí Máil. A sept of the O'Byrne family called the Gaval Rannall possessed the area around Glenmalure, known as Gaval-Rannall or Ranelagh.
The mountains were also formerly known as Sliabh Ruadh or the Red Mountains.
Topography
The Wicklow Mountains are the largest area of continuous high ground in Ireland, having an unbroken area of over above. They occupy the centre of County Wicklow and extend into Counties Dublin, Carlow and Wexford. The general direction of the mountain ranges is from north-east to south-west. They are formed into several distinct groups: that of Kippure in the north, on the boundary of Dublin and Wicklow; Djouce, Tonelagee, Camaderry and Lugnaquilla in the centre; Church Mountain and Keadeen Mountain in the west; and Croghan Kinsella to the south. To the east, separated from the rest of the range by the Vartry Plateau, is the group comprising the Great Sugar Loaf, Little Sugar Loaf and Bray Head.Lugnaquilla is the highest peak in the Wicklow Mountains at and the 13th highest in Ireland. It is also the highest peak in Leinster and is the only Irish Munro to be found outside of Munster. Kippure stands at. There are a total of 39 peaks over in the Wicklow Mountains. There are only three passes through the mountains under with the Sally Gap and the Wicklow Gap being the highest road passes in the country.
Geology
The Wicklow Mountains are primarily composed of granite surrounded by an envelope of mica-schist and much older rocks such as quartzite. The oldest rocks are the quartzites of the Bray Group that include Bray Head and the Little Sugar Loaf and Great Sugar Loaf mountains. These metamorphosed from sandstone deposited in the deep waters of the primeval Iapetus Ocean during the Cambrian period. Layers of sediment continued to form slates and shales along the ocean floor mixed with volcanic rock pushed up as Iapetus began to shrink by the process of subduction during the Ordovician period. These rocks now underlie the uplifted peneplain of the Vartry Plateau between the Bray Group and the main range.The Iapetus Ocean closed up completely at the end of the Silurian period and the Wicklow Mountains were uplifted during the main phase of the Caledonian orogeny at the start of the Devonian period when the continents of Baltica and Laurentia collided. The collision pushed up a large batholith of granite, known as the Leinster Chain: this is the largest continuous area of granite in Ireland and Britain and runs from the coast at Dún Laoghaire in County Dublin to New Ross in County Wexford and includes the Wicklow and Blackstairs Mountains. The heat generated by the collision metamorphosed the slates and shales surrounding the granite into schists which formed an aureole around the granite. The process of erosion has removed much of the surrounding schist from the mountain tops, exposing the underlying granite. Some remnants of the schist roof remain on some of the mountain tops, most notably Lugnaquilla. The round granite-topped peaks contrast with the sharper schist peaks: for example, War Hill and Djouce.
File:Upper and Lower Lough Bray.jpg|thumb|right|The twin corrie lakes of Lough Bray on the eastern face of Kippure
The last major geological event to shape the Wicklow Mountains was the Quaternary glaciation during the Pleistocene epoch. The ice deepened and moulded the valleys into the U-shape that characterises the Wicklow Glens, such as Glendalough and Glenmacnass. As the ice melted, small glaciers were left in corries where moraines now dam lakes such as at Loughs Bray and Nahanagan. Corries without lakes also occur, such as the North Prison and South Prison of Lugnaquilla. Escaping meltwater cut narrow rocky gorges at several locations including the Glen of the Downs, the Devil's Glen and The Scalp. Ribbon lakes, such as Lough Dan and the lakes of Glendalough, also formed.
Mining and quarrying
The zone of collision between the continental plates that led to the formation of the Wicklow Mountains also led to mineralisation and the formation of Ireland's most significant metalliferous belt. The most important mining sites have been at Avoca and Glendalough. Mining has taken place at Avoca since at least the Bronze Age. Iron ore extraction took place between the 12th and 17th centuries before being replaced by lead mining up to the mid-18th century. The principal activity from 1720 to the closure of the last mine in 1982 was copper extraction. Sulphur has also been extracted at certain times and, in smaller quantities, gold, silver and zinc. Lead mining has been the principal activity in the Glendalough valley and its neighbouring valleys of Glendasan and Glenmalure. Lead was first discovered in Glendasan in the early 19th century and the lead veins were later followed through Camaderry mountain to Glendalough. Mining on a smaller scale took place in Glenmalure. Ore from these mines was shipped to Ballycorus for processing. The last mine closed in 1957.In 1795, workers felling timber discovered gold near the Aughatinavought River, a tributary of the River Aughrim, that rises on the slopes of Croghan Kinsella mountain. During the subsequent gold rush in Wicklow, some of gold was recovered from the river by local prospectors, including a single nugget weighing, the largest lump of gold ever discovered in Ireland and Britain. The mine workings were subsequently seized by the British government who extracted a further of gold. Various attempts have been made to locate the motherlode on Croghan Kinsella but to no avail.
Granite from the Wicklow Mountains has been used as a material for many buildings in Wicklow, Dublin city and beyond. According to Wyse Jackson and Caulfield, granite was reportedly first quarried in west Wicklow in the early 1700s "from several openings at Baltyboys near Blessington, and from 1740 in more significant volumes at Woodend and Threecastles nearby and then from Golden Hill quarry" near the village of Manor Kilbride. In 1720, Trinity College Dublin accounts show that one John Bawnan was paid £11-10s-7d for "Blessington Stones delivered for work on the new kitchen" there.
From 1824, the quarries at Ballyknockan provided material for buildings such as the Bank of Ireland on College Green in Dublin, Dún Laoghaire lighthouse and Liverpool Cathedral until they closed in the late 20th century. Similarly, quarries at Glencullen and Barnacullia in the "Dublin Mountains" provided stone for such buildings as the G. P. O. on O'Connell Street and the Industry and Commerce building on Kildare Street in Dublin. Barnacullia, on the slopes of Three Rock Mountain, supplied paving stones to Dublin Corporation, and the quarry at Dalkey supplied granite for Dún Laoghaire Harbour and the Thames Embankment in London.