Backwater Backwater is that part of a river which has been bYFassed by the main flow of stream, though still jained to it. Backwater has a very low rate of flow and hence is virtually unmoving or stagnant. It is commonly formed when the neck of a meander is cut through by the stream leaving its old channel.
Badlands The term badland was originally used to describe part of South Dakota (USA), which was a terrain difficult to traverse. It is now used universally to describe any landscape characterised by deep dissection, ravines, gullies, and sharp-edged ridges. Such landscapes are created naturally by fluvial erosion on rocks, or artificially by over-grazing and soil erosion.
Baguio It is a tropical storm experienced in the Philippines. It occurs specially from July to November.
Bahada(Bajada) Bahada (a Spanish term) is a type of alluvial plain, occurring towards the centre of intermontane basins in arid or semi-arid areas. It is composed of unconsolidated materials, such as sand, gravel and angular scree, which together mantle the underlying rock-cut pediment. Bahadas or bajadas are formed when several alluvial fans join together to form a gently sloping surface lying between upland areas and playa lakes.
Bai-u season The season of heaviest rain in parts of China and Japan in late spring and summer. Since the rains occur during plum-ripening season Gune-July) in Japan, they are also knawn as plum rains.
Banner cloud Banner cloud is a stationary claud which resembles a banner streaming out on the lee side of a mountain peak. It results from condensatian of air as a maist air-current is farced upwards on the windward side af a sharp peak, such as Malterharn and Everest.
Bar Bar is a depasit of sand ar mud in a river channel. It is also defined as an elangated depasit af sand, shingle or mud in the sea; more or less parallel to the shoreline and sometimes linked to. it. Bars ilre formed by the process of longshare drift. Bars are mainly of two types: (i) tidal'bars, i.e., bars cave red by tides; and (ii) sub. merged bars, i.e., bars submerged permanently, especially across the mauth af a river ar harbour (harbour ba0. In meteorology, bar is the unit af atmospheric pressure. One bar is equal to a calumn af mercury 750.062 mm high in a barometer.
Barchan (Barkhan) Barchan or barkhan is a crescent-shaped sand dune, the horns af which point away from the directio.n of the dominant wind. In a barchan, the leeward slape is relatively steep and the windward slope gentle. A barchan can only form in a desert region where winds blow almast constantly from one direction. Barchans can vary in height from a few metres to. over 30 metres. They can occur singly or in groups. The Sahara Desert in Africa and Turkistan .in Central Asia possess the best examples af barchans.
Barometer Barometer is an instrument for measuring atmaspheric pressure. The necessary barometer was invented by Taricelli in 1643. It measures the height of a column that the atmosphere is able to support in a vertical glass tube.
Barrier Beach (Barrier island) Barrier beach is an offshore sandy bar that lies abave high-tide level, usually separated from the caast by a lagoon. When an offshore sandy bar is sufficiently high above high-tide level and has dunes lying on it, it is termed barrier island. Barrier beaches and islands are cammon on relatively shallow gently sloping offshore areas. Palm Beach and Miami Beach in the USA are some of the best examples l1f barrier beaches.
Barysphere Barysphere refers to all of the earth's i~terior which lies beneath the lithosphere. Hence, it irteilides the core, the mantle and asthenosph~f~. However, some geographers have uslKl the term loosely to describe only the core or only the mantle.
Basic Rock An igneous rock that is quartz free and eonlains a low percentage of silica is called basic rock. A basic rock is composed of minerals such as caldum feldspars. Basic rocks are classified into tilttaba~ic rocks (decrease in the amount of feldsJYar) and intermediate rocks (increase in the sodium content of feldspar). Basalt; dolerite and gabbro are examples of bask rocks.
Basisol Basisol is a type of tropical soil. It is characterised by its blackness, its low organic content and its accumulation of calcium carbonate in the form of a concre" tion honzon. Basisol is formed from the wealhering of basalt under humid tropical conditions. It is cOmmon in the trap landscape of the Indian Ocean.
Batholith (Bathylith) Batholith is a very large dome"shaped intrusion of igneous rock (usually granite) several kilometres in depth and extending over hundreds of square kilometres. Batholiths are always associated with an area where mountain building has taken place. They are formed either by gradual igneous replatemei'lt of he country-rock at great depth (the process is termed as granitisation) or by stopping during a mountainbuilding period (called orogeny). Dartmoor; Devon and Mourne mountains in Nodhen\ Ireland are typical examples of exposed batholiths.
Bathyal Zone The zone of the ocean on the continental
slope is called bathyal zone. Bathayal zone lies between the shallow neritic zone and the deeper abyssal zone. Despite the absence of light, there is a flourishing and varied animal life (benthos) in this zone.
Bay A bay is a wide curving indentation made by the sea or a lake in a coast line, usually lying between two headlands. Sometimes, in local context, the term bay is also used to describe the extension of lowland into an upland area.
Beach A beach is an area at the junction at the junction of the land and the sea. It is located on an eroded platform of solid rock, the wave-cut platform, and is generally of a low gradient with a gently concave profile. It is defined as accumulations of materials lying between the lowest level of spring tides and the highest level reached by storm waves. The materials consist of a wide range of particles, from large rock fragments, shangle and sand to fine mud and silt.
Benguela Current It is an ocean current flowing northwards off the coast of South-West Africa. It is characterised by the upwelling of relatively cold water and has an associated effect on the coastal climate of the region.
Benioff zone Named after H. Benioff, Benioff zone extends at an angle of about 45" from the base of an ocean trench. Benioff zone marks the edge of two plate margins where one is overridden by another during the process of subduction (plate tectonics).
Behtl\t)s the term benthos refer~ to life dwelling on the sea-floor. Benthos occur in numerous forms. Sessile benthtl~ ~re fixed to the sea-floor, while vagrant benthos are capable of active movement on or within the sediment.
Bergschrund A dt!~j); narrow crack near the back of a cirqUe glati~f is cailed bergschrund. B~rgschrund marks the Hhe along which a glacier moves away from the cinjue;s backwall.
tHome Biome is a major community of flora and fauna of a region. It generally refers to a climatic region having similar vegehHidh. The ten principal biomes of the world are: mountain and polar regions, tropical rain forest, grasslands, deserts, temperate forests, monsoon forests, deciduous forests,coniferous forests and evergreen shrub forests.
Bltt:tf§ Foo~ Delta A type of delta that extends out into the sea in a fihger-like pattern with sediment deposited on either side of the distributary streams is called bird's foot delta. Such deltas are composed of very fine sediments (largely silt) and develop in conditions where currents clnd tides are relatively weak. The Mississippi Delta in the USA is one of the best examples of the bird's foot delta.
Blirtd Valley Blind valley is a characteristic of limestone regions (Karstic regions). It ends abruptly with a rock wall when its stream disappears underground through a cave or sink-hole.
Blizzard Blizzard is an intensely cold and strong wind accompanied by falling snow. The snow is often whipped up from the ground and visibility is considerably reduced. It is particularly prevalent in Antarctica.
Block Mountain A block mountain is an area of high relief which is bounded on most sides by faults and which has either been uplifted by earth movement or left elevated by the sinking of surrounding areas. The Vosges mountain (France) and Black Forest (Germany) are examples of block mountains.
Blood-Rain Raindrops which contain fine red dust, brought by upper winds from neighbouring desert areas, are called blood-rains. For example, Sahara dust often causes blood-rains over Italy.
Blossom Showers (Mango Showers) Blossom showers or mango showers are the rain showers that occur from March to May in the monsoon region of South-east Asia.
Bluff The term bluff denotes a river-cut cliff or steep slope on the outside of a meander. A line of bluffs often marks the edge of a former flood plain. Bluffs are produced by rivers eroding laterally by cutting into the valley sides.
Bog Bog is general term for morass or swamp. It is also a commonly used term in Scotland and Ireland for a stretch of waterlogged, spongy ground, chiefly composed of decaying vegetable matter. Bogs are widespread in Russia, Scandinavia and Canada. A bog often forms with the growth of moss, especially sphagnum, on the surface of a shallow pond or lake.
Bora A cold, dry northerly or northeasterly wind that blows down through the mountains to the eastern coast of the Adriatic Sea and North Italy is named bora.
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