How Rocks Are Destroyed
The process by which rocks are broken down by the forces of nature.
What is weathering?
The washing away of soil, sand, and vegetation, dramatically changing the face of the land.
What is erosion?
The source of a river.
What is headwaters?
Numerous streams that continue to feed into the river at various points along its course, increasing the amount of water that it carries.
particles too heavy to be lifted by the wind are rolled in short bursts in a process called
creep
deep groves and scratches in rock produced by glaciers
striae
The breakdown of large rocks into fragments by physical forces, such as ice, rapid changes in temperature, and grit carried by wind and running water. (Does not change the chemical composition)
What is physical weathering?
limestone formations that have become filled with various passageways and large caves
caverns
The material carried by a stream.
What is load?
The level or nearly level land that borders a river and is covered by river water in flood time.
What is a floodplain?
A sudden slide of huge masses of rock or soil down a slope
landslide
The pile of debris left when a glacier melts.
moraines
This occurs when rainwater or melted ice soaks into tiny cracks in a rock and freezes; the sudden expansion of the ice as it freezes can split the rock.
What is ice wedging?
This term refers to eroded rock fragments being set down in a new location.
What is deposition?
(A drainage system consists of a relatively large stream and any smaller streams that flow into it.) The region of land drained by a drainage system.
What is a drainage basin or watershed?
The waters are sluggish on the floodplain, while the waters in the river channel maintain a swift current. The difference in water flow causes the river to form natural ridges.
What are levees?
type of landslide that involves fine soil and small pebbles
earth slide
A low hill formed when a glacier overruns a moraine.
drumlin
The breaking or peeling away of rock in layers.
What is exfoliation?
The process of erosion often begins with rain. During a heavy rain, more rainwater may fall than can seep into the ground or evaporate. The excess water is:
What is runoff?
The largest drainage basin in the United States, which covers about half the country.
What is the Mississippi River drainage basin?
When a river on a soft, flat floodplain develops curves and twists, it creates a course that bends like a snake.
What are meanders?
the general term for the downslope movements of rock, soil, volcanic ash, snow, or ice
mass-wasting
ice sheets smaller than continental glaciers
ice caps
When minerals and rock react chemically with air or water, the minerals may weaken or even dissolve, causing the rock to crumble. (the main agent in this process is water, which can be slightly acidic)
What is chemical weathering?
Name the process in which running water carves a channel in the ground that cannot be repaired by ordinary cultivation.
What is gullying?
The western and eastern drainage divides of the Mississippi River drainage basin.
What is the Great Divide (Rocky Mountains) and the Eastern Continental Divide (Appalachian Mountains)?
When a meander is bypassed and becomes cut off from the rest of the river, it forms a crescent-shaped body of water.
What is oxbow lakes?
the process of modifying a smooth slope into a series of level, stair-like steps
terracing
the sharp steeple shaped point of a mountain with three or more cirques
horn
The process where oxygen from the atmosphere reacts with minerals like calcium, magnesium and iron to form new compounds
oxidation
Caverns form due to underground erosion. The buildup of dripstone, causes many formations that hang from the ceiling and grow from the ground.
What are stalactites and stalagmites?
a narrow sandy island formed by a large bar off the coast of the mainland
barrier island
The side of the dune that usually has a gentle slope that progresses up to the crest
Windward side
trees, tall plants, or fences designed to minimize land erosion are examples of
windbreaks
the term that describes a huge hole left in the ground when an ice chunk left by a retreating glacier melts
kettle
The main agent in chemical weathering
water
The roof of a cavern collapses, causing the ground above it to collapse as well.
What is a sinkhole?
A fan-shaped or triangular deposit extending from the mouth of the river into the sea.
What is delta?
The eroding action of windblown sand
abrasion
planting alternate strips of erosion-prone crops with strips of erosion preventing crops
strip-cropping
The name for the time when 1/3 of the earth's land area was covered in glaciers
the stripping away of a thin area of topsoil form the surface of the land
sheet erosion
A stalactite and stalagmite grow until they join.
What is a column?
The sediments are left on the plain in a delta-like deposit.
What is alluvial fan?
sand dunes that is arch shaped with the open end pointing to the windward side
parabolic
a glacial deposit consisting of mixed particle sizes found in the bottom of a valley
till
huge bowl shaped depression dug out by a valley glacier
cirque
type of weathering when a plants roots slowly thicken in a rock
physical weathering
A narrow curved rock formation formed when a sea cave is continually eroded.
Sea arch
a large stream that carries water from the mountains to the sea
river
Suspension, saltation and creep, are examples of this process
eolian
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A sheet of glacial ice that covers an immense area of flat land
continental glacier
karst regions
natural acid found in rainwater and groundwater that promotes chemical weathering
carbonic acid
the name for a vertical face of rock that forms when the sea removes rock from the base of a high ridge.
sea cliff
Large icicle like masses of calcium carbonate found in caves
dripstone
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A glacier-carved valley that has filled with seawater
fjord