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Barra (phase)
Barra (; gd, Barraigh or ; sco, Barra) is an island in the Outer Hebrides, Scotland, and the second southernmost inhabited island there, after the adjacent island of Vatersay to which it is connected by a short causeway. The island is named after Saint Finbarr of Cork. In 2011, the population was 1,174. Gaelic is widely spoken, and at the 2011 Census, there were 761 Gaelic speakers (62% of the population). Geology In common with the rest of the Western Isles, Barra is formed from the oldest rocks in Britain, the Lewisian gneiss, which dates from the Archaean eon. Some of the gneiss in the east of the island is noted as being pyroxene-bearing. Layered textures or foliation in this metamorphic rock is typically around 30° to the east or northeast. Palaeoproterozoic age metadiorites and metatonalites forming a part of the East Barra Meta-igneous Complex occur around Castlebay as they do on the neighbouring islands of Vatersay and Flodday. A few metabasic dykes intrude ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heaval
Heaval is the highest hill on the Outer Hebridean island of Barra, Scotland. The highest point is 383 metres high above sea level and it is located 1.5 km northeast of Castlebay. It is most easily ascended from the south east, from the summit of a 102 m high road pass on the A888 about 1 km east of Castlebay. There is a signposted car park nearby. About halfway up the ridge, there is a white statue of the Virgin and Child. Near the top, the ridge becomes steep, but any difficulties can be bypassed on the south side. The two other hills on Barra with more than 150 metres of reascent are Ben Tangaval (333 m) in the west, and Ben Cliad (202 m) in the north. Another hill, Theisabhal Mor (190 m) is on Vatersay, which is linked to Barra by a causeway. Five of the uninhabited islands A desert island, deserted island, or uninhabited island, is an island, islet or atoll that is not permanently populated by humans. Uninhabited islands are often depicted in films or storie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diorite
Diorite ( ) is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock) that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-silica (mafic) gabbro and high-silica ( felsic) granite. Diorite is found in mountain-building belts (''orogens'') on the margins of continents. It has the same composition as the fine-grained volcanic rock, andesite, which is also common in orogens. Diorite has been used since prehistoric times as decorative stone. It was used by the Akkadian Empire of Sargon of Akkad for funerary sculptures, and by many later civilizations for sculptures and building stone. Description Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and sometimes pyroxene. The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic grani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standing Stone
A menhir (from Brittonic languages: ''maen'' or ''men'', "stone" and ''hir'' or ''hîr'', "long"), standing stone, orthostat, or lith is a large human-made upright rock (geology), stone, typically dating from the European middle Bronze Age. They can be found individually as monoliths, or as part of a group of similar stones. Menhirs' size can vary considerably, but they often taper toward the top. They are widely distributed across Europe, Africa and Asia, but are most numerous in Western Europe; particularly in Ireland, Great Britain, and Brittany, where there are about 50,000 examples, and northwestern France, where there are some 1,200 further examples. Standing stones are usually difficult to date. They were constructed during many different periods across pre-history as part of the larger megalithic cultures in Europe and near areas. Some menhirs stand next to buildings that have an early or current religious significance. One example is the South Zeal Menhir in Devon, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machair (geography)
A machair (; sometimes machar in English) is a fertile low-lying grassy plain found on part of the northwest coastlines of Ireland and Scotland, in particular the Outer Hebrides. The best examples are found on North and South Uist, Harris and Lewis. Etymology ''Machair'' is a Gaelic word meaning "fertile plain", but the word is now also used in scientific literature to describe the dune grassland unique to Western Scotland and north-west Ireland. It had been used by naturalists since 1926, but the term was not adopted by scientists until the 1940s. The word is used in a number of placenames in Ireland and Scotland, even in areas where no machair has ever been supported. In Scotland, some Gaelic speakers use ''machair'' as a general term for the whole dune system, including the dune ridge, while others restrict its use to the extensive flat grasslands inland of the dune ridge. In Ireland, the word has been used only in place-names, and the habitat's existence there was only rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-track Road
A single-track road or one-lane road is a road that permits two-way travel but is not wide enough in most places to allow vehicles to pass one another (although sometimes two compact cars can pass). This kind of road is common in rural areas across the United Kingdom and elsewhere. To accommodate two-way traffic, many single-track roads, especially those officially designated as such, are provided with passing places (United Kingdom) or pullouts or turnouts (United States), or simply wide spots in the road, which may be scarcely longer than a typical car using the road. The distance between passing places varies considerably, depending on the terrain and the volume of traffic on the road. The railway equivalent for passing places are passing loops. In Scotland The term is widely used in Scotland, particularly the Highlands, to describe such roads. Passing places are generally marked with a diamond-shaped white sign with the words "passing place" on it. New signs tend to be sq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peat
Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficient carbon sink on the planet, because peatland plants capture carbon dioxide (CO2) naturally released from the peat, maintaining an equilibrium. In natural peatlands, the "annual rate of biomass production is greater than the rate of decomposition", but it takes "thousands of years for peatlands to develop the deposits of , which is the average depth of the boreal orthernpeatlands", which store around 415 gigatonnes (Gt) of carbon (about 46 times 2019 global CO2 emissions). Globally, peat stores up to 550 Gt of carbon, 42% of all soil carbon, which exceeds the carbon stored in all other vegetation types, including the world's forests, although it covers just 3% of the land's surface. ''Sphagnum'' moss, also called peat moss, is one of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borve, Barra
Borve ( gd, Borgh) is a village on the west coast of the island of Barra in the Outer Hebrides, Scotland. Borve is within the parish of Barra, and is situated on the A888 which is the island's circular main road. History There are a number of neolithic remains nearby, including a burial cairn, and standing stones. A rich Viking burial was unearthed in the vicinity of Borve at a site called Ardvouray in 1862, the contents of which can be found in the British Museum The British Museum is a public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is among the largest and most comprehensive in existence. It docum .... The grave included amongst other things a pair of oval brooches, a comb, fragments of a drinking horn, a spear, a pair of shears, a weaving sword and a whetstone. References External links Canmore - Barra, Borve site record [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machair
A machair (; sometimes machar in English) is a fertile low-lying grassy plain found on part of the northwest coastlines of Ireland and Scotland, in particular the Outer Hebrides. The best examples are found on North and South Uist, Harris and Lewis. Etymology ''Machair'' is a Gaelic word meaning "fertile plain", but the word is now also used in scientific literature to describe the dune grassland unique to Western Scotland and north-west Ireland. It had been used by naturalists since 1926, but the term was not adopted by scientists until the 1940s. The word is used in a number of placenames in Ireland and Scotland, even in areas where no machair has ever been supported. In Scotland, some Gaelic speakers use ''machair'' as a general term for the whole dune system, including the dune ridge, while others restrict its use to the extensive flat grasslands inland of the dune ridge. In Ireland, the word has been used only in place-names, and the habitat's existence there was only re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nappe
In geology, a nappe or thrust sheet is a large sheetlike body of rock (geology), rock that has been moved more than or above a thrust fault from its original position. Nappes form in compressional tectonic settings like continental collision zones or on the overriding plate in active subduction zones. Nappes form when a mass of rock is forced (or thrust fault, "thrust") over another rock mass, typically on a low angle fault plane. The resulting structure may include large-scale recumbent Fold (geology), folds, shearing along the fault plane,Twiss, Robert J. and Eldridge M. Moores, ''Structural Geology,'' W. H. Freeman, 1992, p. 236 Thrust fault#Thrust duplex, imbricate thrust stacks, Window (geology), fensters and klippes. The term stems from the French word for ''tablecloth'' in allusion to a rumpled tablecloth being pushed across a table. History Nappes or nappe belts are a major feature of the European Geology of the Alps, Alps, Dinaric Alps, Dinarides, Carpathians and S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust Fault
A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If the angle of the fault plane is lower (often less than 15 degrees from the horizontal) and the displacement of the overlying block is large (often in the kilometer range) the fault is called an ''overthrust'' or ''overthrust fault''. Erosion can remove part of the overlying block, creating a ''fenster'' (or ''window'') – when the underlying block is exposed only in a relatively small area. When erosion removes most of the overlying block, leaving island-like remnants resting on the lower block, the remnants are called ''klippen'' (singular ''klippe''). Blind thrust faults If the fault plane terminates before it reaches the Earth's surface, it is referred to as a ''blind thrust'' fault. Because of the lack of surface evidence, blind thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dike (geology)
A dike or dyke, in Geology, geological usage, is a sheet of rock that is formed in a Fracture (geology), fracture of a pre-existing rock body. Dikes can be either Intrusive rock, magmatic or Sedimentary rock, sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock. Clastic dikes are formed when sediment fills a pre-existing crack.Essentials of Geology, 3rd Ed, Stephen Marshak Magmatic dikes A magmatic dike is a sheet of igneous rock that cuts across older rock beds. It is formed when magma fills a fracture in the older beds and then cools and solidifies. The dike rock is usually more resistant to weathering than the surrounding rock, so that erosion exposes the dike as a natural wall or ridge. It is from these natural walls that dikes get their name. Dikes preserve a record of the fissures through which most mafic magma (fluid magma low in silica) reac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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