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176 Cards in this Set
- Front
- Back
Remember, as water condenses latent heat is given off. |
.The latent heat given off in an air parcel as condensation takes place, partially offsets the cooling due to adiabatic expansion |
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wet adiabatic lapse rate
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rate at which a saturated air parcel will cool or warm...it is not constant and varies depending upon the amount of water vapor in an air parcel
avg WALR = 5-6 degrees celcius / 1000 meters |
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Environmental lapse rate
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temperature change of the surrounding atmosphere with height.
It is not a parcel lapse rate. Average ELR = 6.5°C/1000 m |
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buoyancy of air
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The tendency of an object to rise in a fluid
A parcel of air moves vertically until the surrounding air is of equal density (equilibrium level) |
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stable
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Rising air is cooler than surrounding air
Resists vertical movement, Non-buoyant Will not move without extra force |
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unstable
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Rising air is warmer than surrounding air
Buoyant Will rise without external force or will continue to rise even after removing the external force |
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conditionally unstable
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Intermediate condition between stability and instability
When an air parcel’s adiabatic lapse rate is between wet and dry rates |
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1. Convective Lifting
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Unequal heating of different air surface areas warming one parcel and not the air around it
only spontaneous of the four lifting types |
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2. orographic lifting
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Occurs only when topographic barriers force air to descend upslope and cool to the dew point
Rain shadow area: the area of low rainfall on the leeward side of a topographic barrier |
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3. frontal lifting
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When unlike air masses meet: air is cooled to the dew point: creation of a zone of discontinuity (front): forces warmer air to rise over cooler air
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4. convergent lifting
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air parcels converge and the crowding forces uplift
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precipitation formation processes
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Two mechanisms principally responsible for producing precipitation:
1. Ice crystal formation 2. Collision and Coalescence of water droplets |
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ice crystal formation
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Possible major reason for precipitation outside tropics
-Ice crystals grow faster than the cloud droplets in clouds that contain both Ice crystals have smaller evaporation rate than cloud droplet. Air gets saturated more quickly by ice crystals than liquid droplets because crystals have a smaller equilibrium vapor pressure |
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collision/coalescence
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Mostly responsible
for precipitation in the tropics -Rain produced by the collision and coalescing (merging) of water droplets No ice crystals because cloud temperatures are too warm Must coalesce enough that the droplets become large enough to fall |
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rain
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The most common and widespread
Drops of liquid water Result of condensations thawing of ice crystals |
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snow
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Solid precipitation in the form of ice crystals, small pellets, or flakes
Formed by direct conversion of water vapor to ice |
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sleet
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Small raindrops freezing during decent
Reach ground as small pellets of ice |
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Distribution of Precipitation
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Spatial distribution: most important geographic aspect of atmospheric moisture |
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Some Generalizations
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Warmer places have the most precipitation but, not all warm places are “wet”
- Mountain areas “wet” - Edges of continents are “wet” - Places with rising air are “wet” - Coastal regions usually receive more precipitation than interior regions because they are closer to moisture sources - Due to rising warm trade winds, tropical latitudes contain most of the wettest areas in the world - The remaining wettest areas are narrow zones along the western coasts of North and South America |
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storms
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Temporary and limited as compared to broad scale pressure and wind systems
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air masses and fronts
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Air masses
Contain uniform temperature and humidity characteristics Fronts Boundaries between unlike air masses |
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locating fronts
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Air masses
Contain uniform temperature and humidity characteristics Fronts Boundaries between unlike air masses |
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Cold Front
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Clouds of vertical development
Short duration, intense precipitation Steep frontal slope |
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Warm Front
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Stratiform clouds
Long duration, light precipitation Gentle frontal slope During summer can get storms also |
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Stationary Front
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Cloud types depend on the atmospheric stability
Precipitation intensity depends on the situation |
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Occluded Front
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Clouds and precipitation depend on the atmospheric stability.
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Atmospheric Disturbances
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Major Disturbances
Midlatitude Cyclones and Anticyclones Hurricanes Minor Disturbances Thunderstorms Tornadoes |
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Midlatitude Cyclones/Extratropical cyclone or wave cyclone
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Migratory low-pressure systemMoves with the westerlies
Responsible for most day to day weather changes |
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Jet Streams
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Rossby waves: undulations in the jet stream.
Usually 3 to 6 span globe at one time. Wavelengths 4000-6000 km. Often takes 10-14 days for a wave to move across US. |
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Storm Tracks: North America
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Storms (Storm Tracks) generally travel from West to East in North America all year
They shift north in summer & south in winter |
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Tropical Weather
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Tropics - region between 23.5° N and S of the equator
amount of solar radiation does not vary much from season to season winds: are generally NE, E, or SE (easterly trades) tend to be quite weak types of weather systems found in tropics: Thunderstorms tropical depressions/storms, and hurricanes |
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Easterly Waves
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Tropical weather is often initiated by easterly waves
easterly waves: * have wavelengths of about 2500 km * position is found in a trough of streamline pattern * convergence/upward motion on east side * divergence/downward motion on west side * travel from east to west at 10-20 knots * hurricanes are often initiated by easterly waves. |
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hurricane formation
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1. The surface air that spirals into the center of a low pressure system creates convergence and forces air to rise in the center. This air cools and moisture condenses which releases latent heat into the air.
2. Warm air is less dense than cooler air. The expansion of warm air forces more air outside away from the center of the storm and the surface pressure decreases. 3. When the surface pressure decreases, a larger pressure gradient is formed, and more air converges towards the center of the storm. This creates more surface convergence and causes more warm moist surface air to rise above the surface. This air, as it cools, condenses into clouds. While it does this, it releases even more latent heat. 4. enhance convection - back to 2. |
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Vertical cross section of the hurricane circulation
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* at low-levels, air flows cyclonically into the center of the storm.
* diverging, anticyclonic motion at tropopause level * rising motion occurs in the eyewall, thunderstorms adjacent to the eye. * subsidence on outer edge of storm * rain bands * sinking motion in the eye |
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Stages of development
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TROPICAL depression: Winds near the center are constantly between 20 and 34 knots (23 - 39 mph).
tropical storms:Once a has intensified to the point where its maximum sustained winds are between 35-64 knots (39-73 mph), it becomes a tropical storm. It is at this time that it is assigned a name hurricanes: As surface pressures continue to drop, a becomes a hurricane when sustained wind speeds reach 64 knots (74 mph). A pronounced rotation develops around the central core. |
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Ingredients for hurricane formation
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* warm sea-surface temps- greater than 26°C (79°F)
* deep moisture at low levels * light winds throughout troposphere * need convergence, a trigger weak frontal boundary easterly wave * typically form between 5°-20° latitude, not on equator.... why? (where all the water isss) -Effect of landfall Hurricanes dissipate rapidly at landfall Remnants may still cause considerable destruction, especially when merging with a midlatitude cyclone |
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Hurricane Destruction and Fatalities
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Wind
Heavy rain Tornadoes Right front quadrant Storm surge Rise in water level associated with pressure drop |
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thunderstorms
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Definition: a storm containing lightning and thunder.
Associated with midlatitude cyclones, localized convection, orographic lifting and tropical cyclones. |
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Thunderstorms
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Violent, localized, short lived
Convective storm Vertical air movement Thunder and lightening Due to unstable uplift Conjunction with other storms (Hurricanes, Tornadoes and fronts etc.) |
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Thunderstorm Formation
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Ingredients
warm, moist air (often mT) unstable (or conditionally unstable) encouraged by diverging air aloft |
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Violent Associations w/ thunderstorms
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Hail
Downbursts(Microbursts) Lightning and thunder Tornadoes |
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Downbursts
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Macrobursts: extreme downdrafts associated with thunderstorms.
Microburst: smaller < 5 minute duration winds up to 146 mph |
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Lightning
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Discharge of electricity that occurs
in mature thunderstorms Cause: charge separation in cloud sets up electrical potential Role of lightning is to equalize these differences in electrical potential. |
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Thunder
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Air poor conductor of electricity
Huge electrical potential develops Lightning bolt ‘superheats’ the air (30,000C, 54,000 F) Surrounding air expands violently sound wave |
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Distance from the Thunderstorm
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Speed of light: 300,000,000 km/s
Speed of sound: about 343 meters/s Distance calculation for each 3 seconds, 1 km away for each 5 seconds, 1 mile away |
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The Geography of Thunderstorms
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Frequency decreases with distance from equator. Few above 60o
Most occur during summer’s warm temperatures. |
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Tornadoes
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Characteristics:
Localized Cyclonic low pressure cells Surrounded by a whirling cylinder of wind violently Partial vacuum develops within the funnel Have the most extreme pressure gradients How fast? No one knows. Estimates: 200 – 500 miles per hour Usually in warm, moist, unstable air masses in mid latitude cyclone |
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Tornado Formation
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Severe Thunderstorm (1% spawn tornadoes)
Often occur along cold fronts and move to NE Strong updrafts Wind shear (change in direction or strength of winds from top to bottom of storm) |
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Funnel Cloud
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(a violent, whirling, funnel-shaped cloud that does not touch the ground. Many people mistakenly call these tornados)
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USA tornado geography
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-every state
-tornado alley (Tx, ok, ks, ne) -most common in us |
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Waterspout
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- A tornodo over water - less power- smaller tempgradient
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USA Tornado Season
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Most common when temperature gradient in central U.S. is greatest.
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hydrosphere
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Describes the waters of the Earth
Water exists on the Earth in stores: atmosphere, oceans, lakes, rivers, soils, glaciers, and groundwater Water moves from one store to another: evaporation, condensation, runoff, precipitation, infiltration and groundwater flow |
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avg reservoir residence time
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The residence time of a reservoir within the hydrologic cycle is the average time a water molecule will spend in that reservoir (table below). It is a measure of the average age of the water in that reservoir, though some water will spend much less time than average, and some much more
oceans (3,200 years) glaciers (20-100 yrs) seasonal snow cover (2-6 months) soil moisture (1-2 months) groundwater: shallow (100-200 years) groundwater: deep (10,000 years) |
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Ice – The Cryosphere
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Second only to the oceans as a place to store water
Land ice Alpine glaciers, ice sheets, ice caps, 10% of the land surface Oceanic Ice – (size) Ice pack, ice shelf, ice flow, iceberg |
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Land Ice – Glacial Ice
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greenland, high latitudes of north america, antarctica
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Earth’s Largest Ice Pack
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arctic ocean
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oceanic ice forms
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ice pack: an extensive and cohesive mass of floating ice
ice shelf: massive portion of a continental ice sheet that projects out over the sea ice flow: large, flattish mass of ice that breaks off from larger ice bodies and floats independently iceberg: a chunk of floating ice that breaks off from an ice shelf or glacier |
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Extent of Permafrost
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Permanently Cold subsoil(ground which remains below 0o C for more than two years)
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Surface Water
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Limited amounts
0.25 percent of the world’s total moisture supply Highly variable in space Used for drinking water, agriculture Sustaining human life |
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lake
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A body of water Surrounded by land
Natural basin having a restricted outlet Sufficient inflow of water to keep the basin filled |
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reservoirs
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artificial lakes
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Swamps
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A body of water with water-tolerant
plants, predominantly trees |
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Marshes
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A body of water with water-tolerant plants, primarily grasses and sedges
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Rivers and Streams
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A natural watercourse flowing towards an ocean or other body of water
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largest drainage basins
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in the middle of continents
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Infiltration Capacity:
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The maximum rate at which water (falling rain or melting snow) can be taken in (absorbed) by soil through the surface.
affected by nature of soil, vegetation, and seasonal factors |
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1. The nature of the soil:
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Permeability: the relative ease of movement of ground water through soil. It is controlled by the degree of connectivity between soil pores.
A highly permeable soil is one in which water runs through it quite readily. Coarse textured soils tend to have large, well-connected pore spaces and hence high permeability. |
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Vegetation
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Plant roots loosen the soil and as a result increase permeability
Plants and plant litter is acting as obstacles (increasing surface roughness) to water flowing over the surface and that gives water a chance to infiltrate. |
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Hydroscopic Water
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: Water that is bound to surface of soil particles by molecular forces. This water can not be evaporated, used by plants or otherwise be removed by natural processes.
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Capillary Water
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The part of soil water which is held as a continuous layer around particles. Most of it being available to plant roots.
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Gravity Water:
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Subsurface water that responds to gravitational force, percolating through the soil.
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Field (Storage) Capacity
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: Maximum capacity of soil to hold water against the pull of gravity.
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Movement of Water Below the Surface
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Capillarity or capillary motion is the ability of a substance to draw another substance into it. It occurs when the adhesive intermolecular forces between the liquid and a substance are stronger than the cohesive intermolecular forces inside the liquid.
Capillarity Moves water firm thick films to thin films |
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Gravity Water:
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Subsurface water that responds to gravitational force, percolating through the soil.
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Ground water
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Water stored underground
2.5 times that found in lakes and streams Found in many places, just need to dig No evaporation Can last a long time Water occupying the saturation zone and moving under the force of gravity. |
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Saturated Zone:
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: Subsurface zone where all pores of the “ground” are filled with water.
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Water Table:
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The boundary between the unsaturated zone containing Soil Water and the Saturation Zone, which holds the Ground Water.
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Aquifers
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Porous rocks saturated with groundwater
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aquicludes
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layers of impermeable rocks
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confined aquifer
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creates an artesian well
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Groundwater mining
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- removal of water from an aquifer at a rate
greater than its flow and recharge capacities Results in: Collapsing aquifers: water in aquifers often provide support for the porous rock, its removal could result in the rock collapsing, in which case the capacity of the aquifer is greatly reduced Saltwater intrusion Contamination of an aquifer by seawater due to over-pumping the aquifer |
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Cone of Depression
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Shape of an inverted coneWhen removal of water from well is faster than its replacement
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The Ogallala Aquifer
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Largest Aquifer in the United states
225,000 square miles Accumulating water for 30,000 years Water about the size of a larger Great Lake Only moderate precipitation today Affected by heavy groundwater mining over the past 100 years, the last 50 especially |
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High Plains Aquifer (Ogallala)
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Water table changes from the early 1900s until 1997
water table has dropped more than 40 feet in places if mining stopped, it would take 1000 years to recharge water used to irrigate grain crops (wheat, sorghum and corn, providing 40% of cattle feed) and cotton the City of San Antonio, TX depends entirely on water from the Ogallala aquifer Underground water does not obey property rights |
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Climatic Zones and Types
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Temperature and precipitation are the most significant and understandable features when classifying climate
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Climate Classification
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Classification Schemes
Generalize a vast array of data in a simple form Way to compare/contrast different areas Examples Ancient Greek Scheme Köppen System Modified Köppen System |
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General Bands of Latitude
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Low Latitude
Between equator and 30° N & S Midlatitude Between 30° & 60° N & S High Latitude > than 60° N & S Equatorial Within a few °’s of the equator Tropical Within the tropics Subtropical Slightly poleward of the tropics 25-30° N & S Polar Within a few °’s of the Poles |
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Ancient Greek Classification
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5 ZONES:
One Torrid (in tropics) Two Temperate (midlatitudes) Two Frigid |
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Köppen System & Modified Köppen System
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Tropical Humid (equatorial regions) (Zone A)
Dry (Deserts: arid & semiarid) (Zone B) Mild Midlatitude (mild winter) (Zone C) Severe Midlatitude (boreal, cold winter) (Zone D) Polar (always cold) (Zone E) Highland (mountains, plateaus) {addition} (Zone H) |
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Modified Köppen System
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Encompasses basic design of Köppen with minor modifications
3 letter system First letter climate group (temperature) Second letter precipitation Third letter temperature patterns Csa Mediterranean C middle latitude temps s summer dry a hot summers (as opposed to warm) Five major climate groupsGroups A, B, C, D, and E14 individual climate typesSpecial category of highland (H) climate |
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Different climates as the basis for different biomes:
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Tropical Rainforest
Tropical Deciduous Forest Tropical Scrub Tropical Savanna Desert Mediterranean Woodland and Shrub Midlatitude Grassland Midlatitude Deciduous Forest Boreal Forest Tundra |
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Climograph?
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Monthly Temperature&Precipitation
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Tropical Humid Climates (Zone A)
Three types (rainfall based) |
Cover most of the land area with 15-20° of the equator
Lack cold weather Very wet 1. Tropical Wet - Af 2. Tropical Monsoon - Am 3. Tropical Savanna - Aw |
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Tropical Wet
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Seasonless
Similar weather all the time Uniform insolation all the time |
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Tropical Monsoonal - Am
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Similar to Tropical Wet
Except heavy rainfall & slightly lower temperatures in summer (high sun season) |
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Tropical Savanna - Aw
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Most extensive of A types
Lesser annual rainfall Wildfires in dry season Lowsun dry season |
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Dry Climates (Zone B)
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30% of land area – More than any other climatic zone
Desert – Extremely Arid Steppes – Semi Arid Subtropical Subtropical Desert (BWh) Subtropical Steppe (BSh) Midlatitude Midlatitude Desert (BWk) Midlatitude Steppe (BSk) |
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Subtropical Desert (BWh)
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Either in or very near subtropical highs e.g. Sahara, Arabian Desert, Australian, Atacama Desert
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Atacama desert
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Rainshadow
14 years without precipitation Deserts Precipitation Scarce Unreliable Intense Temperature Large ranges |
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Subtropical Steppe:
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Around subtropical deserts
Similar temperature & precipitation (not as extreme) |
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Midlatitude Desert:
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Occur deep in interior of continentsCan have cold winters
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Midlatitude Steppe:
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Transition zone between midlatitude desert and humid climate
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Mild Midlatitude Climates (Zone C)
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Equatorward margin of middle latitudesLong and usually hot summersShort & relatively mild winters
Three types Mediterranean Humid Subtropical Marine West Coast |
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Mediterranean
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Western side of continents Influenced by Westerlies Winter wet
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Humid Subtropical
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Eastern side of continents 25–30º of latitude Higher humidity in summer
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Severe Midlatitude Climates (Zone D)
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Only in Northern Hemisphere(no landmasses at appropriate latitudes in Southern Hemisphere)Four Seasons with long cold winters
Moderate precipitation Two types: Humid Continental (Dfa, Dfb, Dwa, Dwb) Subarctic (Dfc, Dfd, Dwc, Dwd) |
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Humid Continental
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Between 35 and 55 Degrees in North America Extends to 60 degrees in Europe
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Subarctic
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Long, dark, bitter cold winters Summers can be warm – huge ATR
Continentality Meager precipitation High mid-latitudes (50° & 70°) Alaska to Eastern Canada & Scandinavia to easternmost Siberia |
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Tundra(ET)
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Low precipitation, cold,
extremely short growing season, low primary production – treeline |
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Highland Climate (Zone H)
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Variation with Elevation
Varies over short distances Both vertically and direction the slope faces North versus south facing slopes Windward vs. leeward |
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Biosphere
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consists of all living things, plant and animal (i.e., flora and fauna).
Processes and interactions within the biosphere are exceedingly intricate – energy, water, & nutrients |
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Biogeochemical Cycles
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The Flow of Energy
The Hydrologic Cycle The Carbon Cycle The Oxygen Cycle The Nitrogen Cycle Interrelated and complex |
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Flow of Energy
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Sun is the basic source of energy
Photosynthesis The production of organic matter by chlorophyll-containing plants and animals Energy fixed or made stable by plants (Chemical Energy) |
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Respiration
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process of "burning" stored chemical energy, basically through oxidation, for maintaining plant metabolism.
During plant respiration, carbohydrates combine with oxygen and is reduced to carbon dioxide, water, and heat. |
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net primary productivity, NPP
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Plant growth occurs so long as photosynthesis exceeds respiration
Plant growth depends on a surplus of carbohydrate production NPP is the difference between photosynthesis minus respiration Measure is Biomass (dry weight of organic material) |
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Hydrologic Cycle
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Most abundant single substance in the biosphere is water
Medium of life processes Source of their hydrogen Watery solutions dissolve nutrients and carry them to all parts of the organism Residence Bound into plant and animal tissues Transit Transpiration-respiration stream |
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Carbon Cycle
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Carbon is one of the basic elements of life
-Carbon based lifeforms Continuous states of creation, transformation and decomposition Main components -Transfere of carbon from CO2 to living matter then back to CO2 -Carbon moves constantly from the living system to organic reservoirs and back. |
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Oxygen Cycle
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O2 is mainly a byproduct of photosynthesis
Other sources... |
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Nitrogen Cycle
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Atmosphere is 78 % Nitrogen
Soil bacteria & cyanobacteria (blue green algae) Nitrogen fixation Conversion of the gaseous form to nitrates (usable by plants) Primarily Soil microorganisms, plants Secondary Lightning & cosmic radiation Marine organisms Synthetic manufacture of nitrogenous fertilizers Nitrogen fixing crops – alfalfa, clover, soybeans |
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fundamental units of a food chain
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plants (autotrophs) fed on by animals (heterotrophs...consumers), which consist of primary consumer herbivores and secondary consumers carnivores
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ecosystems and biomes
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Ecosystem:
Totality of interactions among organisms and the environment in any area Applied at many scales Biome: large, recognizable assemblage of plants & animals in functional interaction with its environment Ecotone—the transition zone between biotic communities in which the typical species of one community intermingle with those of another. Useful for world distribution patterns Described by their dominant veg. type |
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Spatial Groupings of Plants
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Vegetation Associations
-Emphasis is usually based on the structure and appearance of the dominant plants 1.Forests -Trees growing close together 2.Woodlands -Tree dominated – spaced apart 3. Shrublands -Short woody plants 4.Grasslands 5.Deserts 6.Tundra 7.Wetlands |
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The Earth Interior
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Crust: Outermost solid layer
Makes 1% of the Earth’s volume Mantle: Beneath the crust & surrounding the outer core 1800 miles – 84% volume Outer Core: Liquid shell beneath the mantle that encloses Earth’s inner core Inner Core: Evidently solid, dense, innermost portion |
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Earth’s Crust and Mantle
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Lithosphere: The uppermost zone of mantle
Asthenosphere: Layer of upper mantle underlying Lithosphere Very hot, weak and easily deformed Mesosphere: Rigid part of the deep mantle |
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Bedrock
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(Buried layer of the residual rock that has not experienced weathering and/or erosion)
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Igneous Rocks
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(Formed by solidification of molten magma)
Extrusive: Molten rock ejected onto Earth’s surface and solidifies in open air Intrusive: Rocks that cool down and solidify beneath Earth’s surface |
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Sediment
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naturally-occurring material that is broken down by natural processes, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself.
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sedimentary rocks
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Formed by sediment consolidation
by pressure and cementation |
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Formation of Sedimentary Rocks
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Particles deposited by wind or water
-Layers Over time builds up -Compaction Cementation -Infilling of pore spaces --Cementing agent ---Silica ---Calcium carbonate ---Iron oxide |
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Relative Abundance of Sedimentary Rock Types
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Sandstone
-Compacted sand grains Shale -Compacted silt and clay particles Limestone -Chemically or organically produced --Calcium carbonate --Skeletal remains lime secreting creatures |
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Metamorphic Rocks
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Originally was something else (igneous/sedimentary) but has changed by heat and/or pressure within the Earth.
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Rift Valley Formation
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Begins on a continent
East African Rift Valley Grows to become linear sea (“proto-ocean”) Red Sea Constructive boundary (rock is created) |
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Plate Boundaries
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Divergence (Seafloor Spreading)
Convergence (Collision) Lateral (Transform) |
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ocean floor rocks
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-basalt covered with thin layer of sediments
-oceanic crust rocks in crust vis a vis surface rocks |
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isostasy
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vertical movement of the crust to buoyancy in the mantle
-the crust rises and sinks because it is lighter than the underlying mantle -variations in elevation are due both to thickness and density. the continents stand high because continental crust is thick and light. the ocean basins are low because oceanic crust is thin and dense |
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Convergent Plate Boundary: Ocean-to-Continent
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Subduction trenches (“slab pull”) next to continents
Destructive boundary: Rock is destroyed via subduction E.g., Andes Mountains and Cascade Range |
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Convergent Plate Boundary: Ocean-to-Ocean
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Subduction trenches in deep ocean
Destructive boundary: Rock is destroyed via subduction Island arcs – e.g., Aleutian Islands and Mariana Islands |
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Convergent Plate Boundary: Continent-to-Continent
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No subduction
Conservative boundary: Rock is neither created nor destroyed Folded Mountains: e.g., Himalayas |
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Diastrophism
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General term referring to the deformation of the earth’s crust
-Implies the material is solid -Plate boundary movement 2 Types -Folding -Faulting |
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Folding
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Occurs when rock is compressed.
-upturned folds are called anticlines -down turned folds are called synclines -anticlines and synclines are geologic structures, that is, they are folds in rock material |
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faulting
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When enormous stresses build and push large intact rock masses beyond their yield limit, faulting of the surface is likely to occur. A fault is a fracture along which movement occurs.
The plane that extends into the earth and along which slippage occurs is called the fault plane. Breaking apart of crustal material -Displacement -Occurs in zones of weakness in the crust -Fault line or zone -Four types 1Normal 2Reverse faults 3Thrust faults 4Strike-slip faults |
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Normal Faults
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Tension stresses
-Pulling apart Pushed up |
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Reverse faults
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Due to compression
Upthrown block rises steeply above the downthrown block |
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Strike Slip fault
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movement is horizontal
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thrust
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compression forces the upthrown block over the downthrown block
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Earthquakes
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Vibration of the earth produced by shock waves resulting from the sudden displacement usually along a fault
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p wave
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fastest moving, alternatively compressing and relaxing the material they pass through
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s waves
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slow moving, producing both side to side and up and down motion
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magnitude
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Widely mentioned – least understood
-Calculated on a logarithmic scale -Difference between small (3) and large (7) is enormous --1,000,000 times more energy Common scale -Richter |
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landforms
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Configuration of the land surface taking distinctive forms and produced by natural processes.
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Structural (Initial, Constructional) Landforms
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: Landforms that are created by the solidification of large quantities of magma and/or by massive movements of rock due to plate tectonics.
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Compression
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occurs when rock masses are pushed together like that which occurs when plates collide. Rocks tend to shorten laterally and thicken vertically when exposed to compressional stress
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graben
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downdropped block, often forming a long narrow valley
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horst
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an upthrown block, forming a plateau or mountain
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Earthquakes
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An earthquake is a sudden vibration or trembling in the Earth
Most earthquakes are produced along faults, tectonic plate boundary zones, or along the mid-oceanic ridges Large masses of rock that are moving past each other can become locked due to friction. Friction is overcome when the accumulating stress has enough force to cause a sudden faults of the rock masses. The magnitude of the shock wave released into the surrounding rocks is controlled by the quantity of stress built up because of friction, the distance the rock moved when the fault occurred, and ability of the rock to transmit the energy. |
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Volcanoes
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A volcano is a conical shaped landform built by the emission of lava and gases from a constricted vent in the Earth’s surface.
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magma chamber
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a huge, subterranean reservoir of molten rock
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central vent
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main conduit through which magma moves toward surface
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lateral vents
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found on the sides of some volcanoes where magma is extruded
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crater
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sits at the top of a volcano and is the location where much of the lava, gas, rock fragments and ash are ejected from
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lava
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word for magma (molten rock) when it erupts onto earth's surface
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tephra
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general term for fragments of volcanic rock and lava regardless of size that are ejected from the volcano.
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classification of volcanoes based on:
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the magma chemistry,
explosiveness of the eruption, the geomorphic form. |
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Basalt plateau (Flood Basalts)
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Basalt plateaus occur mainly in tectonic divergence zones and “hot spots”.
Extensive continental deposits of basaltic volcanic rock Very fluid basaltic magma with horizontal flows. Form is flat Can occupy an area from 100,000 to 1, 000,000 km2. Lava deposit can be up to 1,800 m thick. The least explosive type of volcano Some basaltic magmas can produce very large slightly sloping volcanoes, 6 to 12°, that have gently flowing magmas called shield volcanoes Shield volcanoes can be up to 9000 m tall |
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Hot Spot
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A volcanic area on the surface of the Earth created by a rising plume of magma.
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Cinder Cone
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small volcano, between 100 and 400 meters tall, made up of exploded rock (tephra) blasted out of a central vent at a high velocity.
They form when large amounts of gas accumulate within rising basalt magma. The rain of tephra accumulates around the vent to form a roughly circular hill Rarely grow more then few hundred meters |
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Composite volcanoes
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are made from alternate layers of viscous lava flows and tephra
Form from alternating eruptions dominated by tephra or lava. As a result, composite volcanoes display layers of these alternating flows. The chemistry of the magma is quite variable ranging from basalt to granite. Magmas hold large amounts of gas under high pressure, and can produce highly explosive eruptions of tephra along with white-hot gases and fine ash. Conical in Shape. Height ranges from 100 to 3500 meters tall. |
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Calderas
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When a stratovolcano has a very violent eruption it is possible for the entire central portion of the volcano to be destroyed. The volcanic mountain may actually collapse in on itself forming a large depression, called a caldera.
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volcanic neck
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As volcanic activity subsides, magma may cool in the central vent and, over thousands of years, the overlying cone is worn away to expose the harden rock inside
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dike
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Radiating away from the central vent may be nearly vertical fractures into which magma can intrude and cool. Erosion of the overlying surface reveals a linear, fin-like ridge radiating away from the volcano
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mountain
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can be defined as an area of land that rises abruptly from the surrounding region.
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mountain range
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a succession of many closely spaced mountains covering a particular region of the Earth.
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mountain belts
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belts consist of several mountain ranges that run roughly parallel to each other. (The North American Cordillera, the Himalayas, the Alps, and the Appalachians are all examples of mountain belts that are composed of numerous mountain ranges.)
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Some mountains are volcanic in origin forming where rising magma breaks through the Earth's surface. Volcanic mountains tend to have sporadic distributions within a mountain range or can occur alone because of a localized hot spot.
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Denudation
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: total action of all processess whereby the exposed continental rock are worn down and removed.
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