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.
A fan-shaped or triangular deposit extending from the mouth of the river into the sea.
What is delta?
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?
This type of erosion occurs beneath the earth's surface, producing networks of underground cavities known as:
What are caves?
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?
The sediments are left on the plain in a delta-like deposit.
What is alluvial fan?
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?
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?
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?
A stalactite and stalagmite grow until they join.
What is a column?
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 roof of a cavern collapses, causing the ground above it to collapse as well.
What is a sinkhole?