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Geology Of National Parks In Britain
The geology of national parks in Britain strongly influences the landscape character of each of the fifteen such areas which have been designated. There are ten national parks in England, three in Wales and two in Scotland. Ten of these were established in England and Wales in the 1950s under the provisions of the National Parks and Access to the Countryside Act 1949. With one exception, all of these first ten, together with the two Scottish parks were centred on upland or coastal areas formed from Palaeozoic rocks. The exception is the North York Moors National Park which is formed from sedimentary rocks of Jurassic age. Three new national parks have been created in lowland England since the late 1980s, these being the Broads, South Downs and New Forest national parks. (Strictly speaking the Broads was not created as a national park but the Broads Authority has since adopted the name for marketing purposes.) The landscape of these areas reflects the fact that they are all establis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Parks Of The United Kingdom
National parks of the United Kingdom ( cy, parciau cenedlaethol; gd, pàircean nàiseanta) are areas of relatively undeveloped and scenic landscape across the country. Despite their name, they are quite different from national parks in many other countries, which are usually owned and managed by governments as protected community resources, and which do not usually include permanent human communities. In the United Kingdom, an area designated as a national park may include substantial settlements and human land uses that are often integral parts of the landscape. Land within national parks remains largely in private ownership. These parks are therefore not "national parks" according to the internationally accepted standard of the IUCN but they are areas of outstanding landscape where planning controls are a little more restrictive than elsewhere. Within the United Kingdom there are fourteen national parks of which nine are in England, three in Wales and two in Scotland. Ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karst
Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes. However, in regions where the dissolved bedrock is covered (perhaps by debris) or confined by one or more superimposed non-soluble rock strata, distinctive karst features may occur only at subsurface levels and can be totally missing above ground. The study of ''paleokarst'' (buried karst in the stratigraphic column) is important in petroleum geology because as much as 50% of the world's hydrocarbon reserves are hosted in carbonate rock, and much of this is found in porous karst systems. Etymology The English word ''karst'' was borrowed from German in the late 19th century, which entered German ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silt
Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when dry, and lacks plasticity when wet. Silt also can be felt by the tongue as granular when placed on the front teeth (even when mixed with clay particles). Silt is a common material, making up 45% of average modern mud. It is found in many river deltas and as wind-deposited accumulations, particularly in central Asia, north China, and North America. It is produced in both very hot climates (through such processes as collisions of quartz grains in dust storms) and very cold climates (through such processes as glacial grinding of quartz grains.) Loess is soil rich in silt which makes up some of the most fertile agricultural land on Earth. However, silt is very vulnerable to erosion, and it has poor mechanical properties, making construc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Till
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is diagnostic of till. image:Glacial till exposed in roadcut-750px.jpg, Glacial till with tufts of grass Till or glacial till is unsorted glacier, glacial sediment. Till is derived from the erosion and entrainment of material by the moving ice of a glacier. It is deposited some distance down-ice to form terminal, lateral, medial and ground moraines. Till is classified into primary deposits, laid down directly by glaciers, and secondary deposits, reworked by fluvial transport and other processes. Description Till is a form of ''glacial drift'', which is rock material transported by a glacier and deposited directly from the ice or from running water emerging from the ice. It is distinguished from other forms of drift in that it is d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anglian Glaciation
The Anglian Stage is the name used in the British Isles for a middle Pleistocene glaciation. It precedes the Hoxnian Stage and follows the Cromerian Stage in the British Isles. The Anglian Stage is correlated to Marine Isotope Stage 12 (MIS 12), which started about 478,000 years ago and ended about 424,000 years ago.Lisiecki, L.E. (2005Ages of MIS boundaries. Boston MA:Boston University Description The Anglian stage has often been correlated to the Elsterian Stage of northern Continental Europe and the Mindel Stage in the . Ho ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superficial Deposits
Superficial deposits (or surficial deposits) refer to geological deposits typically of Quaternary age (less than 2.6 million years old). These geologically recent unconsolidated sediments may include stream channel and floodplain deposits, beach sands, talus gravels and glacial drift and moraine. All pre-Quaternary deposits are referred to as bedrock. Types and history There are several types of superficial deposit, including raised beaches and brickearth. These were formed in periods of climate change during the ice ages. The raised beaches were generally formed during periods of higher sea level, when ice sheets were at a minimum, and the sand and shingle deposits can be seen in many low cliffs. The brickearth is originally a wind-blown dust deposited under extremely cold, dry conditions but much has been re-deposited by flood water and mixed with flints. Superficial deposits were originally recorded only onshore and around the coast where they were laid down by various n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neogene
The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago (Mya) to the beginning of the present Quaternary Period Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868). During this period, mammals and birds continued to evolve into modern forms, while other groups of life remained relatively unchanged. The first humans ('' Homo habilis'') appeared in Africa near the end of the period. Some continental movements took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off the warm ocean currents from the Pacific t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter). The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts (mainly shells) of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies ( marine snow). Sedimentation may also occur as dissolved minerals precipita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Broads
The Broads (known for marketing purposes as The Broads National Park) is a network of mostly navigable rivers and lakes in the English counties of Norfolk and Suffolk. Although the terms "Norfolk Broads" and "Suffolk Broads" are correctly used to identify specific areas within the two counties respectively, the whole area is frequently referred to as the Norfolk Broads. The lakes, known as broads, were formed by the flooding of peat workings. The Broads, and some surrounding land, were constituted as a special area with a level of protection similar to a national park by the Norfolk and Suffolk Broads Act 1988. The Broads Authority, a special statutory authority responsible for managing the area, became operational in 1989. The area is , most of which is in Norfolk, with over of navigable waterways. There are seven rivers and 63 broads, mostly less than deep. Thirteen broads are generally open to navigation, with a further three having navigable channels. Some broads ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Llyn Y Fan Fach
Llyn y Fan Fach (Welsh meaning "little lake (near) the peak") is a lake of approximately on the northern margin of the Black Mountain in Carmarthenshire, South Wales and lying within the Brecon Beacons National Park. The lake lies at an altitude of approximately , immediately to the north of the ridge of the Carmarthen Fans. It is the smaller of two lakes within this mountain massif: the slightly larger Llyn y Fan Fawr is about to the east. Geology The lake is overlooked by several prominent mountain peaks, especially Picws Du and Waun Lefrith. Waun Lefrith is formed from the sandstones and mudstones of the Brownstones Formation of the Old Red Sandstone laid down during the Devonian period. Its southern slopes are formed from the hard-wearing sandstones of the overlying Plateau Beds Formation which are of upper/late Devonian age. It is those rocks which form vertical crags along the top edge of the scarp. The northern face of Waun Lefrith was home to a glacier during the ice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Llyn Cwm Llwch
Llyn Cwm Llwch () is a small lake or pool in the Brecon Beacons National Park in Powys, Wales. It is between 1 and 2 acres: much smaller than the two glacial lakes in the west of the Black Mountain (range): Llyn y Fan Fawr and Llyn y Fan Fach, and one of the few natural bodies of water in the park. It is of glacial origin, occupying a rock hollow beneath the peaks of Pen y Fan and Corn Du in the central Brecon Beacons. It is drained by the Nant Cwm Llwch which empties into the Afon Tarell, which itself enters the River Usk at Brecon. Tommy Jones' obelisk, a memorial in granite to a young boy who died near this spot in 1900, overlooks the lake. Geology The lake occupies a hollow excavated in the sandstones of the Brownstones Formation of the Old Red Sandstone by glacial action during the succession of recent ice ages. Its northern margins are rimmed by a large curved late-glacial moraine.British Geological Survey 1:50,000 map sheet 231 'Brecon' & accompanying sheet explanation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brecon Beacons
The Brecon Beacons ( cy, Bannau Brycheiniog, ) are a mountain range in South Wales. In a narrow sense, the name refers to the range of Old Red Sandstone peaks which lie to the south of Brecon. Sometimes referred to as "the central Beacons" they include South Wales' highest mountain, Pen y Fan. The range forms the central section of the Brecon Beacons National Park (), a designation which also encompasses ranges both to the east and the west of "the central Beacons". This much wider area is also commonly referred to as "the Brecon Beacons", and it includes the Black Mountains to the east as well as the similarly named but quite distinct Black Mountain to the west. The highest peaks include Fan Brycheiniog to the west and Pen y Fan in the central part. They share the same basic geology as the central range, and so exhibit many similar features, such as the north-facing escarpment and glacial features such as lakes and cwms (cirques). Geography The Brecon Beacons range, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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