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84 Cards in this Set
- Front
- Back
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What are external process?
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Processes such as weathering, mass wasting and erosion that are powered by the energy from the sun and happen on or near Earth's surface.
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What are internal processes?
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Processes that get their energy from Earth's interior such as mountain building and volcanic activity.
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What is weathering?
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The physical breakdown and chemical alteration of rock at or near Earth's surface.
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What is mass wasting?
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The transfer of rock and soil downslope under the influence of gravity.
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What is erosion?
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The physical removal of material by a mobile agent such as flowing water, waves, wind, or ice.
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What does a trigger do?
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It initiates downslope movement.
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What is angle of repose?
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It is the steepest angel at which material remains stable.
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Removal of vegetation increases erosion. Where plants are lacking, what is enhanced?
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Mass wasting
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What is the most important and dramatic mass-wasting triggers.
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Earthquakes
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Describe the water cycle.
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The constant movement of water through the atmosphere, solid earth and the biosphere.
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What is infiltration?
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When a portion of precipitation soaks into the ground.
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What is runoff?
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When the rate of rainfall exceeds Earth's ability to absorb it, and the surplus water flows over the surface into lakes and streams.
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Describe transpiration.
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When water from the ground is absorbed by plants and release into the atmosphere.
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What is water balance?
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The volume that passes through each part of the water cycle annually.
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What is the single most important agent sculpturing Earth's land surface?
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the volume of moving water.
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Which step is the primary action that wears down Earth's land surface?
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Land-back-to-the-sea step.
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What is velocity?
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The distance that water travels in a unit of time.
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What factors determine the velocity of a stream?
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1)gradient 2)shape,size,and roughness of channel 3)discharge
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What is gradient?
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the slope of a stream channel expresses as the vertical drop of a stream over a specified distance.
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What is discharge?
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The volume of water flowing past a certain point in a given unit of time.
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What is a profile of a stream?
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A cross-sectional view of a stream from its source area (head) to its mouth.
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What is base level?
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The lowest point to which a stream can erode its channel.
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Sea level is the ultimate base level. Why?
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Because it is the lowest level to which stream erosion could lower the land.
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What is temporary, or local, base levels?
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The lakes, resistant layers of rock, and main streams that act as base level for their tributaries.
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What is incised meanders?
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A winding river in a steep, narrow valley.
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What are Earth's most important erosional force?
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Streams
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What are the 3 ways streams transport their load of sediment?
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1) in solution 2)in suspension 3)scooting or rolling along the bottom
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Dissolved loads are contributed by what?
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Groudwater
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How do most streams carry the largest part of their load?
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In suspension.
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What is the bed load?
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The coarser particles that move along the bottom of the stream channel.
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What is competence?
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It measures the maximum size of particles it is capable of transporting.
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What is capacity?
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The max load a stream can carry.
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What is sorting?
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The process by which solid particle of carious sizes are separated by moving water or wind.
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What is alluvium?
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The well-sorted material deposited by a stream.
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What is a delta?
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An accumulation of sediment formed where a stream enters a lake or ocean.
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What are distributaries?
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When the main channel divides into several smaller ones. They carry the water away from the channel.
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What are natural levees?
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The elevated landforms that parallel some streams and act to fine their waters, except during flood stage.
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What are backswamps?
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Poorly drained areas on a floodplain that result when natural levees are present.
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What are yazoo tributaries?
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Tributaries that flow parallel to the main stream because a natural levee is present.
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What are the 2 types of valleys?
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Narrow V-shaped and wide valleys
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How is a floodplain formed?
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They result from the side-to-side cutting of a stream.
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The side-to-side cutting when a river erodes laterally makes what kind of floodplain?
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An erosional floodplain.
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How is an depositional floodplain formed?
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When a major fluctuation in conditions, such as a change in base level, occur.
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What are meanders?
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A loop like bend in the course of a stream.
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What is a cutoff?
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A short channel segment created when a river erodes through the narrow neck of land between meanders.
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What is an oxbow lake?
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A curved lake produced when a stream cuts off a meander.
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Streams erode their channels in what 3 ways?
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1)lifting loose particles, 2)abrasion (grinding), 3) by dissolving soluble materials.
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What are the three types of deltas?
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1) triangle, 2)birds foot 3) estuary
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What causes a flood?
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When the discharge of a stream becomes so great that it exceeds the capacity of its channel and over-flows its banks.
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What are flash floods?
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Floods that occur with little warning and rise very rapidly.
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What are artificial levees?
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Earthen mounds built on the banks of a river to increase the volume of water the channel can hold.
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What are flood-control dams?
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Dams that are built to store floodwater and then let it out slowly.
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What is channelization?
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The altering of a stream channel to speed the flow of water to prevent it from reaching flood height.
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What is a drainage basin?
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The land area that contributes water to the stream.
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What is a divide?
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An imaginary line that divides one drainage basin from another.
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What is a dendritic pattern drainage system?
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It is the most common type. It has irregularly branching tributary streams that branch out like at tree.
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What is a radial pattern drainage system?
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When streams diverge from a central area like spokes from the hub of a wheel.
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What is a rectangular pattern drainage system?
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When the stream has many right-angle bends.
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Describe a trellis drainage pattern.
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It is a rectangular pattern in which tributary streams are nearly parallel to one another and have the appearance of a garden trellis.
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What represents the largest reservoir of readily available fresh water?
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Groudwater
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What is the belt of soil moisture?
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The near the surface zone where water soaks in but doesn't go far because it is held to soil.
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What are all the open spaces in sediment and rock that are completely filled with water called?
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zone of saturation
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What is groudwater?
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The water that is within the zone of saturation.
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What is the water table?
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The upper limit of the zone of saturation.
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What is the zone of aeration?
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The zone about the water table where the soil, sediment, and rock are not saturated.
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How does ground water move?
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Very slowly, from pore to pore.
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What is porosity?
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The percentage of the total volume of rock or sediment at consists of pore spaces.
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What is permeability?
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material's ability to transmit water.
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What are aquitards?
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Impermeable layers that hinder or prevent water movement.
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What are aquifers?
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Permeable rock strata or sediments that transmit groundwater freely.
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What is a spring?
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A natural outflow of groundwater that happens when the water table intersects Earth's surface.
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What is a hot spring?
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A spring in which the water is usually 10-15 degrees warmer than the mean annual air temperature of its locality.
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What are geysers?
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Intermittent hot springs or fountains in which columns of water are ejected with great force at various intervals.
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What is a well?
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The most common method for removing groundwater where a hole is bored into the zone of saturation.
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What is drawdown?
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Whenever a substantial amount of water is withdrawn from a well and the water table around the well is lowered.
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What is the cone of depression?
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When the depression of the water table makes a conical shape.
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What does artesian mean?
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When ground water rises in a well above the level where it was initially encountered.
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What are the 2 ways for an artesian event to occur?
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1) water is confined to an aquifer that in inclined so that one end is exposed at the surface where it can receive water? 2) There are aquitards above and below the aquifer to prevent the water from escaping.
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What is a cavern?
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A naturally formed underground chamber or serious of chambers most commonly produced by solution activity in limestone.
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What are stalactites?
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Icicle-like pendants that hang from the ceiling of the cavern and form where water seeps through cracks above.
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What are stalagmites?
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Formations that develop on the floor of a cavern and reach upwards toward the ceiling.
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What forms if a stalactite and a stalagmite join?
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THey make a column.
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What is karst topography?
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Landscapes that are shaped by the dissolving power of groundwater.
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What are sinkholes/sinks?
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Depressions produced in a region where soluble rock has been removed by groundwater.
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