Forces that Change Earth’s Surface
Points to Remember
Points to Remember
- External forces associated with weathering and erosion wear down Earth’s surface. Internal forces associated with faulting and volcanism build up Earth’s surface.
- Weathering is the breaking down of rocks into smaller pieces. Weathering is caused by physical agents such as ice wedging and chemical agents such as oxygen rusting the iron in rocks.
- Erosion is the transport of rock material from one place to another. Running water is the major agent of erosion.
- Change in Earth’s surface is the result of the interactions of the lithosphere, hydrosphere, and atmosphere over various ranges of time.
- Plate tectonics explains how the crust consists of a series of plates that move and interact causing earthquakes and volcanism. Most earthquakes and volcanoes are located on the boundaries of plates.
- Major seafloor features are associated with plate tectonics. Mid-ocean ridges are areas where hot rock material comes to earth’s surface and pushes outward in both directions. Trenches are deep, ocean-floor features where one plate slides down under another plate.
- Continental drift was initially supported by the fit of the continents, fossil correlation, and rock formations. Today plate tectonics and ocean-floor features strongly support that the continents were once together.
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