B Flashcards
Back-wall
The steep cliff face at the rear of a corrie.
Backshore
The beach above the high water, or high tide, mark which is usually untouched by wave action.
Backward integration
Vertical integration in an upstream direction i.e. a company merging with or buying out a supplier.
Backwash
(1) In physical geography, the movement of water down a beach to the sea after having run up the beach in the swash.
(2) In human geography, the movement of resources from periphery to core through a series of circuits: capital concentrates in the core, depriving the periphery and reducing wealth generation there; migration tends to take younger, more employable workers to the core leaving older, less productive workers in the periphery; lack of investment in services, amenities and infrastructure further widen the gap.
Backwater
Area of still water created by an impediment to drainage e.g. a sediment bar across an ox-bow lake.
Bacteria
A class of organisms known as Prokaryotes in which the cell has no nucleus. They are single-cell microbes which can be found virtually everywhere. They ‘eat’ almost anything which lends them an enormous variety of very useful functions, although they can also be responsible for sickness. Geographers may be interested in the role they play in health patterns, especially in the ELDW, or in soil formation, or many other topic areas.
Bahada
Gently sloping plain formed when a number of alluvial fans exiting closely spaced wadis in desert areas coalesce into a larger feature.
Balance of payments
Net sum of a country’s income from and expenditure on foreign trade which can run to a surplus or a deficit.
Balance of trade
The net sum of imports and exports of visible goods. Forms part of the balance of payments along with the same calculation for invisibles.
Bankfull discharge
The maximum discharge that a particular river channel is capable of carrying without flooding.
Baobab tree
A pyrophitic tree found in savannah areas. It has an enormous trunk which stores water and tiny leaves to minimize evapotranspiration.
Bar
See sand bar.
Barchan
Crescent-shaped sand dune which forms in desert areas experiencing generally constant winds. The ‘horns’ of the crescent point downwind, having moved ahead more rapidly, where they become sheltered and stable. Sand moves up the windward side and collapses down the leeward side which is steeper. This net movement of sand from the windward to the leeward side causes the dune to move forwards.
Bar chart
Bars of equal width placed within perpendicular axes and used to represent varied amounts or frequencies through variations in length.
Barrage
A dam or barrier with adjustable gates and sluices built across an estuary in order to harness tidal energy.
Barrier beach
Low-lying, bar-shaped sand and/or coral island lying parallel to but slightly away from a coastline. The landward side tends to be marshy or a lagoon.
Basal sapping
The undercutting and retreat of a slope caused when erosion and / or weathering are concentrated at its base.
Basal slipping
During summer time in warmer glacial areas, limited melting lubricates the base of the glacier allowing it to move more freely. Movement increases pressure, raising temperature and allows further melting as the ice reaches its pressure melting point.
Basalt
An igneous rock, fine-grained and glass-like, formed by rapidly cooled lava often under water.
Base flow
That portion of river discharge derived from groundwater flow.
Base level
The lowest elevation to which erosion can take place. Usually sea-level but could be lower if a river drains into an inland sea or lake whose level is below sea-level.
Basic volcano
Where low viscosity, extremely hot lava flows from a vent it will spread rapidly to form a shallow sloped, low altitude cone.
Batholith
A massive intrusive volcanic feature. Magma forces its way into the crust but becomes trapped and solidifies into rock e.g. granite.
Battery farming
Intensive, commercial livestock (usually poultry or cattle) production where animals are reared in cages and fed and watered automatically to reduce the per unit cost. May also include hormone treatment.
Bay
A curved indent to the coastline, usually created by greater erosion rates than neighbouring parts of the coast. Bays often contain beaches and provide an area of shelter both for boats and for settlements.
Beach
Accumulation of sand and shingle material at a coast or at the fringes of a body of water due either to low energy brought about by sheltered conditions or due to an excess of sediment.
Beach depletion
Net loss of sand and / or shingle from a beach due to reduced replenishment while removal processes such as longshore drift continue unabated. Natural replenishment rates are thought to have slowed as sea-levels have risen, river loads have reduced, beaches have stabilized and humans have dredged offshore sediments.
Beach nourishment
Human replenishment of depleted beaches using material from land pits or dredged deposits. Beach material may be allowed to move by longshore drift before being returned to where it started.
Beaufort scale
A scale for wind speed, and therefore strength, based on observable effects.
Bedding plane
The boundary between adjacent layers or strata in a sedimentary rock.
Bedload
Larger load which is unable to move in suspension but is transported by saltation and traction.
Bedrock
Solid rock underlying other surface materials.
Benioff Zone
Boundary between an oceanic plate undergoing subduction beneath a continental plate. Characterized by earthquakes and the melting of the oceanic plate.
Benthos
Marine organisms which dwell on the seabed.
Bergeron-Findeison process
A theory of raindrop formation. At temperatures between -5°C and -25°C both water droplets and ice crystals exist in the same space. Vapour is sublimated onto the ice crystals and the deficit in vapour is compensated by the evaporation of the water droplets leading to further sublimation and thus growth of the ice crystals. These may coalesce into snowflakes which then overcome gravity and fall. When air temperatures at the surface are greater than zero the flakes melt into water drops before they land.
Bergschrund
A large crevasse at the upper portion of a corrie glacier, close to the back-wall.
Berm
A low ridge towards the rear of a beach marking the uppermost level that waves reached during the previous high tide.
Best-fit line
A line drawn on a scatter-graph, as close to all the points as possible, which thus indicates any trend in the pattern. Points that are very disparate may not provide an opportunity to draw a best-fit line and thus show no trend or correlation. If the points all lie on the line, the correlation is perfect.
