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Example: Mid-Atlantic Ridge
Effects:1. Creates a submarine mountain range2. Volcanic activity in the form of fissure eruptions3. Shallow earthquake activity4. Creates new sea floor and widens ocean basins
Example: East African Rift Valley
Effects:1. Sometimes occupied by fresh or salt water2. Many normal faults in the rift valley3. Shallow earthquakes along the faults4. Sometimes there is volcanic activity in the rift valley
Magma from the mantle
Magma from the mantle
Mid-Atlantic Ridge
East AfricanRift Valley
Example: Andes Mountains in South America
Effects:1. A zone of earthquake activity along the continent margin2. Sometimes ocean trenches form offshore3. A line of volcanic eruptions a few hundred miles inland4. Destruction of oceanic crust
Example: Aleutian islands
Effects:1. A zone of progressively deeper earthquakes2. An oceanic trench3. A chain of volcanic islands4. Destruction of oceanic crust
Mid-Atlantic Ridge
East AfricanRift Valley
Andes Mountains
Aleutian islands
Example: Himalaya Mountain Range
Effects:1. Intense folding and faulting2. A broad folded mountain range3. Shallow earthquake activity4. Shortening and thickening of the continental plates
Example: San Andreas Fault
Effects:1. Location of recurring earthquake activity and faulting2. The earthquakes are usually shallow3. Volcanic activity is normally NOT present
Mid-Atlantic Ridge
East AfricanRift Valley
Andes Mountains
Himalaya Mountains
Aleutian islands
San Andreas Fault
Theory of Continental Drift-- the theory that the earth's continents move gradually over the surface of the Earth.
Theory of Plate Tectonics-- the theory that the Earth’s lithosphere is broken into plates that float on the asthenosphere.
Convection current-- cooler, denser rock near the astenosphere sinks while hotter, less dense rock in the lower mantle rises driving the movement of the tectonic plates.
Tension-- a force that pulls two plates apart from each other.
Divergent Boundary-- plate boundary where two plates are moving away from each other because of tension.
Compression-- a force that pushes two plates together.
Convergent Boundary-- plate boundary where two plates are pushed together because of compression.
Subduction--A type of plate movement that happens when one plate sinks beneath another plate.
Shear force– a force that fractures rock along a plane because of movement in opposite directions.
Transform Boundary– plate boundary where two plates are moving parallel to each other in opposite directions because of shear force.
