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Swansea Valley Disturbance
The Cribarth Disturbance is a geological structure forming a lineament which stretches across south Wales from Swansea up the Swansea Valley then northeastwards to Brecon and beyond. It consists of both a series of faults and associated folds which were active during the mountain-building period known as the Variscan orogeny. This line of weakness probably featured in the earlier Caledonian Orogeny and perhaps reflects a more ancient line of weakness in the basement rocks. It is also known (in part) as the Tawe Valley Disturbance or the Swansea Valley Disturbance. Influence on the landscape The Disturbance is responsible for a number of significant landscape features along its 50 km length. Prominent amongst these is the Swansea Valley, formed both by glacial action during the ice ages and river erosion along this line of weakness in the Earth's crust between Abercraf and Swansea. It is now occupied by the River Tawe. The geologically complex mountain of Cribarth also lies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lineament
''See also Line (geometry)'' A lineament is a linear feature in a landscape which is an expression of an underlying geological structure such as a fault. Typically a lineament will appear as a fault-aligned valley, a series of fault or fold-aligned hills, a straight coastline or indeed a combination of these features. Fracture zones, shear zones and igneous intrusions such as dykes can also be expressed as geomorphic lineaments. Lineaments are often apparent in geological or topographic maps and can appear obvious on aerial or satellite photographs. There are for example, several instances within Great Britain. In Scotland the Great Glen Fault and Highland Boundary Fault give rise to lineaments as does the Malvern Line in western England and the Neath Disturbance in South Wales. The term 'megalineament' has been used to describe such features on a continental scale. The trace of the San Andreas Fault might be considered an example.Whitten & Brooks, The Penguin Dictionary of Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Tawe
The River Tawe (; cy, Afon Tawe ) is a long river in South Wales. Its headwaters flow initially east from its source below Llyn y Fan Fawr south of Moel Feity in the Black Mountains, the westernmost range of the Brecon Beacons National Park, before the river turns south and then southwest to its estuary at Swansea. Its main tributaries are the right bank Upper and Lower Clydach Rivers and the Afon Twrch. The total area of the catchment is some . The Tawe passes through a number of towns and villages including Ystradgynlais, Ystalyfera, Pontardawe, and Clydach and meets the sea at Swansea Bay below Swansea. The Tawe Valley ( in Welsh) is more commonly known as the Swansea Valley. Ownership of the riverbed was granted to the Duke of Beaufort in the 17th century by Charles II resulting in exclusive mineral and fishing rights, which is extended as far as requiring permission and payment for bridges which are built over it. This was last exercised in 2008 when Swansea Cou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Highland Boundary Fault
The Highland Boundary Fault is a major fault zone that traverses Scotland from Arran and Helensburgh on the west coast to Stonehaven in the east. It separates two different geological terranes which give rise to two distinct physiographic terrains: the Highlands and the Lowlands, and in most places it is recognisable as a change in topography. Where rivers cross the fault, they often pass through gorges, and the associated waterfalls can be a barrier to salmon migration. The fault is believed to have formed in conjunction with the Strathmore syncline to the south-east during the Acadian orogeny in a transpressive regime that caused the uplift of the Grampian block and a small sinistral movement on the Highland Boundary Fault. Discovery One of the earliest and most prominent references to the Highland Boundary Fault was by George Barrow in 1912 ʻOn the Geology of Lower Dee-side and the Southern Highland Borderʼ, which highlights the nature of the rocks accompanying the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Uplands Fault
The Southern Uplands Fault (or occasionally Southern Upland Fault) is a fault in Scotland that runs from Girvan (or more specifically from the Rhins of Galloway) to Dunbar on the East coast. It marks the southern boundary of the Scottish Midland Valley and the northern margin of the Southern Uplands; indeed it is recognised as a boundary between these two terranes. Both sinistral and dextral strike-slip movement is recorded from parts of the fault as are down-north and down-south normal movements suggestive of a complex history. The Stinchar, Dove Cove and Glen App faults form a part of the Southern Upland Fault Zone in the southwest whilst in the northeast, the Lammermuir, Dunbar-Gifford, Crossgatehall, Pentland and Firth of Forth faults are all associated with the Southern Uplands Fault.Oliver, G.J.H, Stone, P. & Bluck, B.J. 2002 ''The Ballantrae Complex and Southern Uplands terrane''. In Trewin, N.H. (ed) ''The Geology of Scotland'', The Geological Society, London p191-2 S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carreg Cennen Disturbance
The Carreg Cennen Disturbance is a zone of geological faults and folds in south and mid Wales which forms a part of both the Church Stretton Fault Zone and the Welsh Borderland Fault System. To the southwest it is known as the 'Llandyfaelog Disturbance'. These structures which stretch from Pembrokeshire to Shropshire are thought to have originated during the Caledonian Orogeny or mountain-building period. Influence on the landscape It is most impressively revealed at Carreg Cennenhttps://www.geograph.org.uk/search.php?i=4967683 images of Carreg Cennen on Geograph website itself where the mediaeval castle sits perched atop a 90m cliff of Carboniferous Limestone which is caught up within a faulted block sitting between two arms of the Disturbance. It is probably also responsible for the alignment of the Afon Cennen to the west of this location where the river follows the line of the fault for over 2.5 mi / 4 km. The Caledonian Orogeny The Carreg Cennen Disturbance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neath Disturbance
The Neath Disturbance is a geological structure which stretches across south Wales from Swansea Bay northeastwards as far as Hereford in western England. It consists of a series of both faults and associated folds which were active during the mountain-building period known as the Variscan orogeny. This line of weakness probably featured in the earlier Caledonian Orogeny and perhaps reflects a more ancient line of weakness in the basement rocks. The Disturbance gives rise to a lineament crossing the region, that is to say that it is responsible for a number of significant landscape features along its 100 km length. Prominent amongst these is the Vale of Neath, a deep valley incised by a glacier during the ice ages along this line of weakness in the Earth's crust and now occupied by the River Neath between Pontneddfechan and Swansea Bay. The hill of Moel Penderyn also lies on the Disturbance a little further east. A part of the Vale of Grwyne north of The Sugarloaf and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeozoic Era
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''zōḗ'' (), "life", meaning "ancient life" ). It is the longest of the Phanerozoic eras, lasting from , and is subdivided into six geologic periods (from oldest to youngest): # Cambrian # Ordovician # Silurian # Devonian # Carboniferous # Permian The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon and is followed by the Mesozoic Era. The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Arthropods, molluscs, fish, amphibians, reptiles, and synapsids all evolved during the Paleozoic. Life began in the oce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iapetus Ocean
The Iapetus Ocean (; ) was an ocean that existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale (between 600 and 400 million years ago). The Iapetus Ocean was situated in the southern hemisphere, between the paleocontinents of Laurentia, Baltica and Avalonia. The ocean disappeared with the Acadian, Caledonian and Taconic orogenies, when these three continents joined to form one big landmass called Euramerica. The "southern" Iapetus Ocean has been proposed to have closed with the Famatinian and Taconic orogenies, meaning a collision between Western Gondwana and Laurentia. Because the Iapetus Ocean was positioned between continental masses that would at a much later time roughly form the opposite shores of the Atlantic Ocean, it can be seen as a sort of precursor of the Atlantic, and the process by which it opened shares many similarities with that of the Atlantic's initial opening in the Jurassic. The Iapetus Ocean was therefore named for the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Structure Of Great Britain
The geological structure of Great Britain is complex, resulting as it does from a long and varied geological history spanning more than two billion years. This piece of the Earth's crust has experienced several episodes of mountain building or ' orogenies', each of which has added further complexity to the picture. A wide range of geological structures occur across Britain and include examples at a variety of scales of: * faults *thrust faults * folds *sedimentary basins * grabens ''and'' horsts *unconformities Our understanding of Britain's large-scale structure has been gained over many decades by simple geological field survey together with an increasing range of technological methods including gravity surveys, seismic surveys, aeromagnetic surveys and other forms of remote sensing. Terranes A useful approach to considering Britain's geological structure is to examine the various terranes from which it is composed. These are essentially continental fragments whose boundar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cribarth
Cribarth, sometimes referred to as the Sleeping Giant, is a hill in the Brecon Beacons National Park located in the traditional county of Brecknockshire (currently administered part of the unitary authority of Powys) in southern Wales. The summit lies on the broken ridge at an elevation of at OS grid reference SN 831143. To its west is a rounded top at SN 829144 which lies just to the northwest of a mile-long ridge that forms the main bulk of the hill. The ridge attains a height of at its southwest end and this spot is marked by a trig point. Both of these latter high points are adorned by Bronze Age burial cairns. Geology The hill is formed from both Carboniferous Limestone rocks and the Namurian age Twrch Sandstone (former 'Basal Grit') of the Marros Group (former 'Millstone Grit Series'), also dating from the Carboniferous Period. It lies on the northeast-southwest aligned geological structure known as the Cribarth Disturbance and indeed gives its name to that regionally im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abercraf
Abercraf ( en, Abercrave) is a village within the historic boundaries of the county of Brecknockshire, Wales, administered as part of the unitary authority of Powys, and in the community of Ystradgynlais. Between 1965 and 1991, the village was the location of a Royal Observer Corps monitoring bunker, to be used in the event of a nuclear attack. It remains mostly intact. Location Abercraf lies in the extreme south of the county, in the Upper Swansea Valley 2.5 miles (4 km) northeast of the small town of Ystradgynlais. It is situated just outside the boundaries of the Brecon Beacons National Park and the Fforest Fawr Geopark, which lie to the immediate north, east, and west of the village. Coal and iron A small ironworks was established in 1824 by the local coalowner, Thomas Harper. Its purpose was to exploit two patents granted to Harper and his fellow coalowner, John Christie (also owner of the Brecon Forest Tramroad) in 1823 (no 4848) and 1824 (no 4909) for the use of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wales
Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the Bristol Channel to the south. It had a population in 2021 of 3,107,500 and has a total area of . Wales has over of coastline and is largely mountainous with its higher peaks in the north and central areas, including Snowdon (), its highest summit. The country lies within the Temperateness, north temperate zone and has a changeable, maritime climate. The capital and largest city is Cardiff. Welsh national identity emerged among the Celtic Britons after the Roman withdrawal from Britain in the 5th century, and Wales was formed as a Kingdom of Wales, kingdom under Gruffydd ap Llywelyn in 1055. Wales is regarded as one of the Celtic nations. The Conquest of Wales by Edward I, conquest of Wales by Edward I of England was completed by 1283, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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