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38 Cards in this Set
- Front
- Back
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What are fluvial landforms?
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Landforms created by running water. (Not landforms made by ice, wind, and waves though).
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What process has done more to shape our Earth than any other process?
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Fluvial Processes
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What is erosion?
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The wearing away of land and soil through the process of running water.
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What are some examples of erosion?
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Gully and arroyos.
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What is deposition?
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The placement of the material carried by running water.
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What is an example of deposition?
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Deltas
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What is a splash erosion?
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A direct force of falling drops on base soil causing a geyserlike splashing in which soil particles are lifted and then dropped into new positions.
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What is accelerated erosion?
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The removal of soil much faster than it can be formed (overgrazing, forest fires remove vegetation and erosion starts).
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What is an example of accelerated erosion?
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Badlands (in South Dakota, Colorado, etc...).
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What are badlands?
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They are underlain by clay formations which do not allow water to seep through therefore the water must go as runoff and it erodes the surface features.
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What are the 3 mechanisms of stream geology?
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1.) Suspension
2.) Dissolved 3.) Bed Load |
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What is stream erosion?
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Removal of material from the floor and sides of a channel.
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What is stream transporation?
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Movement of the eroded particles.
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What is suspension?
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Material is held up by the water in the stream.
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What is dissolved?
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Material is mixed with water (salts, etc...).
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What is bed load?
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Sand, gravel, and cobbles move by rolling or sliding from water flow.
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What is saltation?
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Bouncing or skipping along stream bed.
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What is traction?
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Rolling or sliding.
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What is stream deposition?
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Depositing the material carried by the stream; Occurs when there is a major change in stream discharge.
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What is stream gradiation?
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The SLOW reduction in the height of the headwaters of a stream through time as the stream eroded away the surrounding materials.
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What are the 4 steps of stream gradiation?
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1.) Stream established on land recently uplifted.
2.) Gradiation in progress (lake draining & deepening gorge). 3.) Graded profile attained, beginning of floodplain, valley widening. 4.) Flood plain widened to hold meanders. |
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What is a knickpoint?
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A term in geomorphology to describe a location in a river or channel where there is a sharp change in channel slope, such as a waterfall or lake, resulting from differential rates of erosion above and below the knickpoint.
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What is a thalweg?
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The deepest and fastest moving water.
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What is a floodplain?
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The belt of low, flat ground present on one or both sides of a stream channel and is the area subject to flooding by that stream.
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What are the 2 types of streams?
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1.) Meandering stream
2.) Braided stream |
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What is a meandering stream?
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The river has only one main channel that wanders (or meanders) from side to side of the floodplain.
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What is an example of a meandering stream?
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Rivers in the eastern U.S., Mississippi River.
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What is a braided stream?
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The flow is divided into multiple threads and these rejoin and subdivide as new sandbars within the river form; tend to be very shallow.
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What is an example of a braided stream?
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Most streams in the western U.S. if they aren't dammed, the Salt or Gila rivers.
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What are cutbanks?
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Areas where fast flowing water (the thalweg) erodes away at the side of the river; Found at the outer banks of the stream.
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What are sandbars?
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Areas opposite the cutbanks; Areas of DEPOSITION due to slow-moving water (away from the thalweg).
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What are sandbars sometimes called in the East.
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Pointbars
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What do sandbars and cutbanks continually do?
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Reshape the river, causing it to create bigger and bigger meander loops; Eventually they have the formation of ox-bow lakes.
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What is an ox-bow lake?
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The isolated loop of water, cut off from the river, creating "U"-shaped lake.
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What is an example of an ox-bow lake?
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Crescent Lake, Iowa
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What is a meander scar?
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When the ox-bow lake dries up and is no longer linked to the river and it becomes a marshy swamp.
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What is a delta?
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Deposition of material dropped at the river mouth, called after the Greek letter delta but not all deltas look like that.
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What is an example of a delta?
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Nile River, Mississippi River
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