Geography Ch 3 & 4
Terms
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- asthenosphere
- partially molten layer above earth's interior
- diastrophism
- the great pressure acting on the plates that deforms them by folding, twisting, warping, breaking, or compressing rock
- faults
- fractures in rock along which there has been movement
- folds
- rock layers that have buckled under pressure by the movement of lithospheric plates
- igneous rocks
- rocks formed by the colling and solidification of molten rock (intrusive - magma; extrusive - lava)
- metamorphic rocks
- formed by igneous and sedimentary rocks by earth forces that generate heat, pressure or chemical reaction
- mineral
- particular chemical comination that has a hardness, density, and definite crystal structure
- plate tectonics
- theory that lithosphere is meade up of 12 large and many small plates drifting over the asthenosphere
- sedimentary rocks
- composed of particles of gravel, sand, silt and clay eroded from already existing rocks
- subduction
- collisions of plates with different types of crust at their edges - denser but thinner oceanic crust is forced down into athenosphere
- tsunami
- very large sea waves caused by an earthquake or volcanic eruption below an ocean
- volcanism
- the force that transports heated material to or toward the surface of the earth
- warping
- the bowing of a large region of the earth's surface due to the movement of continents or the melting of glaciers
- gradational processes
- processes responsible for the reduction of land surface (weathering, mass movement, and erosion)
- weathering
- the breakdown and decomposition of rocks and minerals at or near the earth's sruface in response to atmospheric factors (ater, air, and temperature
- mechanical weathering
- physical disintegration of earth materials at or near the surface
- chemical weathering
- processes which cause rock to decompose rather than disintegrate (oxidation, hydrolysis, carbonation)
- mass movement
- the downslope movement of material due to gravity
- erosional agents
- forces such as wind, water, and glaciers which carve already existing landforms into new shapes
- floodplain
- a valley area surrounding a stream which is subject to inundation by flooding
- alluvium
- sand and mud which builds up in temporary lakes called playas at the bottom of hillsides
- continental drift
- theory that all landmasses were once united in one supercontinent named Pangaea and that over many millions of years the continents broke away from each other, slowly drifting to their current positions
- glacier
- large body of ice moving slowly down a slope or spreading outward on a land surface
- loess
- wind deposited material taht is silty in texture and plae yellow or buff in color
- water table
- when underground water accumulates, the upper level of the zone of saturation is caleld the water table
- weather
- temperature, wind, and precipitation
- troposhere
- lowest layer of the earth's atmosphree, which extends about 10 km above the ground and contains viturally all of the air, clouds, and precipitation of the earth
- reflection
- process of potentially receivable solar radiation sent back to outer space or diffused in the troposphere
- reradiation
- process in which the energy that is absorbed into the land and water during the day is returned to the atmosphere in the from of terrestial radiation at night
- temperature inversion
- condition in which air at lower altitudes is cooler than air aloft (dangerous because surface air is trapped)
- air pressure
- the weight of the atmosphere as measured at a point on the earth's surface
- air mass
- a large body of air with little horizontal variation in temperature, pressure, and humidity
- convection
- the circulatory motion of descending cool air and ascending warm air
- sea breeze
- airflow from the sea to the land, resulting from a daytime pressure gradient that moves winds from the cooelr sea gradient to the warmer land surface
- Coriolis Effect
- in moving from high to low pressure, wind veers toward the right of the dirction of travel in the Northern hiemisphere and toward the left in the Southern Hemisphere
- jet stream
- strongest flow of upper air winds, moving from west to east in both the northern and southern hemispheres
- monsoon
- a wind system that reverses direction seasonally, producing wet and dry seasons
- North Atlantic drift
- massive movement of warm water to northerly lands
- convectional precipitation
- precipitation resulting from rising, heated, moisture-laden air
- orographic precipitation
- precipitation which occurs as warm air is forced to rise because hils or mountains block moisture-landen winds
- cyclonic (aka frontal) precipitation
- the rain or snow that is produced when mosit air of one air mass is forced to rise over the edge of another air mass
- relative humidity
- a percentage measure of the mositure content of the air, expressed as the amount of water vapor present relative to the maximum that can exist at the current temperature
- hurricane
- an intense tropical cyclone
- typhoon
- hurricane in the western pacific
- blizzard
- the occurrence of heavy snow and high winds
- tornado
- most violen of all storms; characterized by a funnel shaped cloud of moving winds
- soil horizons
- layers of soil of various thicknesses
- soil properties
- merals, organic matter, water, and air
- climate
- the long-term average weather conditions in a given region
- tropical rain forest
- areas taht straddle the equator; warm, wet climates in both winter and summer; daily rainfall
- savanna
- areas to the north and south of the rain forest; wet and hot in the summer months; dry the remainder of the year
- steppes
- moderately dry lands
- Mediterranean climate
- clear, dry air predominates; winters are relatively short and mild; plants and flowers grow year round
- humid subtropical climate
- hot moist summers and moderate moist winters
- marine west coast climate
- more rainfall and cooler termperatures than mediterranean zones in teh winter; summers are pleasantly cool, winters are cold but not freezing
- humid continental climates
- a climate of east coast and continental interiors of midlatitudes, displaying large annual temeprature ranges resulting from cold winters and hot summers; preicpitation at all seasons
- El Nino
- the periodic (every 3 to 7 or 8 years) buildup of warm water along the west coast of South American; replacing the cold Humboldt current off the Peruvian coast, El Nino is associated with both a fall in plankton levels and short-term, widespread weather modification
- La Nina
- the cool ebb in low-latitude Pacific Ocean surface temperatures that occurs between El Nino peaks of sea-surface warming
- global warming
- a rise in surface temperatures on earth, a process believed by some to be caused by human activities that increase the concentration of greenhouse gases in teh atmosphere, maginifying the green house effect
- greenhouse effect
- the heating of the earth's surface as shrotwave solar energy passes through the atmosphere, which is transparent to it but opaque to rereadiated longwave terrestrail energy
- tundra
- the treeless area lying between the tree line of Arctic regions and the permanently ice-covered zone