Theory of plate tectonics
Floats on top of the athenophere
Lithosphere plates
How does a transform boundary occur?
when two plates move past each other
How does a convergent boundary happen?
When two plate come together, or converge, causing a collision.
What is a land feature?
An example of a land feature is a mountain range
What is a volcano?
A volcano is an opening in the Earth's crust where hot liquid rock from deep within the Earth erupts to the surface.
What rises in the atenosphere and spreads out beneath the lithosphere?
convection currents
What happens when two plates move past each other and get stuck when there is a transform boundary?
Stress builds up and they move in opposite directions forming faults (frequent earthquakes)
How do volcanoes occur?
They occur when two continental plates collide and form mountains which over time might become a volcano.
What is a fossil?
Traces of an ancient organism preserved in rock
What does active, dormant, and extinct mean according to volcanoes?
Active means has erupted recently or is currently erupting.
Dormant hasn't erupted in a long time but still has the potential to erupt.
Extinct means scientists think it will never erupt again.
Convection currents cause what to move?
plates
How does a divergent boundary happen?
When two plates move apart or diverge; usually occurs at the mid-ocean ridge; creates new oceanic crust
What is a continental drift?
The gradual movement of continents over geological time.
What is climate change?
Climate change describes a change in the average conditions — such as temperature and rainfall — in a region over a long period of time (Wegener)
What is an explosive volcano?
Some kinds of volcanos just ooze out lava over time. The lava is generally very thin. Other volcanoes have thicker lava that can plug up the vents and pressure builds up over time. When pressure gets high enough, the volcano can erupt with a huge explosion.
What are some changes in the earth's surface?
volcanoes, mountain ranges and deep ocean trenches
When does a rift valley occur?
When a deep valley is formed along a divergence boundary that develops on land.
How fast do plates move?
Plates move slowly, about 1/2 centimeter a year (same rate as fingernails grow)
What could Wegener not provide?
A satisfactory explanation for the push or pull of the continents; therefore his hypothesis was rejected.
What is a cinder cone, composite, shield, and lava dome?
Cinder cone- formed from particles and blobs of lava ejected from a single vent at the top.
Composite- Shaped like a cone but are formed from layers of lava over many years. they grow into huge mountains; very tall.
Shield- form from wide, thin layers of lava that eventually are shaped like a shield; wider not taller.
Lava dome- Formed by thick lava that hardens raround the vent.
Who is Alfred Wegener and what did he do?
Alfred Wegener hypothesized that at one time all the continents were once joined together in a single landmass, he named it Pangea, and have since drifted apart. This is now known as a continental drift.
When is a foreshock and aftershock?
Foreshock: before an earthquake
Aftershock: after an earthquake
Generally before and after a large earthquake there will be stalled earthquakes.