Underwater mountain chains that form plate boundaries are called:_________________
Mid Ocean Ridges
100
Deep valleys known as ____________________occur where oceanic curst plunges back into the Earth's interior.
Trenches
100
Meltted rock deep within the Earth because of intense heat is called_________________
Magma
100
The theory that Earth's crust and upper mantle are broken into sections is called______________
plate tectonics
100
A_______________is created where one plate moves under another.
trench
200
The San Andreas Fault in California is an example of a ______________ boundary.
Transform
200
Many scientists believe that the lithospheric plates move across the surface of the Earth by ____________________ in the mantle.
convection currents
200
Most volcanoes occur near plate __________________
Boundaries
200
Plates are composed of the_________________
crust and part of the upper mantle
200
The area where a plate descends is a _____________
subduction zone
300
The youngest rocks on the ocean floor are found at ______________boundaries.
Divergent
300
The process of ______________ involves crust of the Earth being returned back into the mantle of the Earth.
subduction
300
An opening in the Earth's surface through which magma flows is a _______________
Volcano
300
The lithosphere is composed of the________________
crust and upper mantle
300
When ocean plates collide with continental plates, the denser ocean plate ___________
Sinks
400
Cracks in the mountains on the ocean floor allow magma to move through Earth's crust and form a new crust. This process is called: ____________________
Sea floor spreading
400
Boundaries where plates slide past each other are__________
transform
400
Magma that reaches Earth's surface is called___________
Lava
400
Plates float on the
asthenosphere
400
The boundary between two plates that are moving apart is a _________boundary.
divergent
500
Wegener thought the continents were like giant puzzle pieces that had moved apart. His idea was known as_______________
Continental Drift Theory
500
Boundaries at which plates collide are___________
Convergent
500
The area where most volcanoes and earthquakes occur is known as the ______________and it surrounds the _____________ ocean.
Ring of Fire and Pacific
500
The type of boundary that is on the western coast of South America is a __________________boundary