Plate Boundaries
What is created when oceanic plates diverges?
Seafloor spreading and then magma comes up and forms the mid-ocean ridge.
Explain how volcanoes are formed.
Magma from the mantle comes to the surface and erupts out due to pressure, heat, and density differences. If the volcano keeps erupting then the volcano will get bigger and bigger.
What happens when plates converge?
-Earthquakes
-Mountains can form
-Crust can be destroyed if one plate goes under another plate
Who came up with the theory of Continental Drift?
Alfred Wegener
What is Pangea?
The large landmass or super continent when all of the continents were joined together.
What happens when plates have a transform boundary? Is land created, destroyed, or neither?
The plates rub and slide past each other.
Land is not destroyed or created.
What is the Ring of Fire?
Located in the Pacific Ocean, there are frequent earthquakes and volcanic eruptions-this makes a chain or string of volcanoes and earthquakes.
What do the plates do to create earthquakes?
The plates are moving and shaking. They may also be sliding/rubbing against each other.
Explain how Wegener used climate clues to support his theory of Continental Drift?
Explain how the ages of rocks on the ocean floor can support the theory of seafloor spreading?
The rocks get older as you move farther away from the mid-ocean ridge.
Explain what is created when 2 oceanic plates collide.
The older/more dense plate will subduct. This causes earthquakes and tsunamis. Then a chain of volcanoes or volcanic islands may form.
What do the plates do to create a Mid-Ocean Ridge? (same as creating a rift valley)
The plates are a divergent boundary. The Mid Ocean Ridge is an underwater mountain range.
Describe the three types of plate boundaries we have learned about and show how they move.
Divergent-pull apart
Convergent- go towards each other/collide
Transform-Slide/rub past each other
How are the Himalayan Mountains formed?
The Indian Plate and the Eurasian Plate are colliding.
What is the lithosphere made of?
This is Earth's outermost layer and is made from rocks in the crust and upper mantle.
It is on top of the asthenosphere.
Name the thing that the tectonic plates float on.
The asthenosphere
Describe the three types of plate boundaries where volcanic eruptions can happen.
Divergent Boundary
Ocean-Continent Convergent
Ocean-Ocean Convergent
What type of plate boundary is the San Andres Fault part of?
It is a transform boundary
When continental plates diverges, what is created?
A rift valley appears. Magma may also come up and make new crust.
Who used sonar in the 1960's to support the theory of seafloor spreading?
Harry Hess
Explain why glacial deposits (evidence of glaciers) have been found in Africa when it is warm there.
Africa was located near the South Pole when the continents were joined.
Explain what is created when an oceanic plate and a continental plate collide.
The thinner, more dense oceanic plate with subduct under the continental plate. This can cause earthquakes to happen and volcanoes to form.
This is the point on the Earth's surface directly above where an earthquake actually begins underground.
The Epicenter
Explain how new seafloor forms at mid-ocean ridges.
Magma moves upward and out of cracks in the seafloor. As it solidifies on the surface, new seafloor forms. The older seafloor moves further away from the ridge.
Explain how convection currents are related to plate tectonics.
The movement of the convection currents in the mantle causes the movement of the plates.