Terms in this set (49)
What is plate tectonics the theory of???
describes how tectonic plates move and shape Earth's surface
What are tectonic plates???
huge pieces of crust and rigid upper mantle that fit together at their edges to cover Earth's surface
How fast do tectonic plates move???
slowly - only a few centimeters a year
What is tectonic plate movement similar to???
the growth of fingernails
Where do tectonic plates move???
different directions at different rates
Where do tectonic plates interact with each other???
at their boundaries
What does each type of boundary have???
certain geologic characteristics and processes associated with it
What causes divirgent boundaries???
two tectonic plates are moving apart
Where are divergent boundaries found???
along the sea floor in rift valleys
What begins at divergent boundaries???
What does the formation of new ocean crust at most divergent boundaries account for???
the high heat, flow, volcanism, and earthquakes associated with these boundaries
What is a rift valley???
long narrow depression that forms when continental crust begins to seperate
What is an example of a rift valley???
What happens at convergent boundaries???
two tectonic plates are moving toward each other
What happens when two tectonic plates collide???
the denser plate eventually descends below the other, less-dense plate in a process called subduction
When did the subduction zone form???
when one ocean plate descends below another oceanic plate
What is oceanic plate made mostly of???
dense basaltic rocks
What does water carried into Earth by the subduction plate lower???
the melting temperature of the plate causing it to melt at shallower depths
What happens because the magma is less dense???
it rises back to the surface where it often erupts and forms an arc of volcanic islands that parallel the trench
What is an example of when the magma is less dense???
marianas trench and marianas islands
What happens to cause an oceanic-continental???
an oceanic plate and a continental plate collide
What does the oceanic continental create???
an ocean trench and a volcanic arc
What does oceanic continental result in???
chain of volcanoes along the edge of the continental plate
What is an example of oceanic continental???
Peru-Chile Trench and the Andes Mountain Range
What happens in a continental-continental???
two continental plates collide
Why cannot continetal crust descend???
because continental rock are less dense and will not sink into the mantle
What happens to the continental plates in a continental-continental???
beome crumpled, folded, and uplifted
What does continental-continental form???
vast mountain ranges
What is an example of continental-continental???
What is a transform boundary???
region where two plates slide horizontally past each other
What are transform boundaries characterized by???
long faults and shallow earthquakes
What happens in a transform boundary???
crust is neither destroyed or formed
What is an example of a transfrorm boundary???
San Andreas Fault
Which theory states that Earth's crust and rigid upper mantle move in different directions and at different rates over Earth's surfac???
Tectonic plates interact at places called plate___???
Places where tectonic plates move apart are called___???
Where are most divergent boundaries found???
on the seafloor
What happens along a divergent boundary???
new ocean crust forms
The Mid Atlantic Ridge is an example of___???
Places where tectonic plates are called___???
Convergent boundaries are classified according to the___???
type of crust involved
Oceanic crust is made mostly of___???
Which of the following features forms when two oceanic plates converge???
What can happen when two oceanic plates converge and one is subducted into the mantle???
melted magma erupts and forms an arc of islands
Which of the following landforms results from divergence of continental crust???
a rift valley
Which of the following best describes what happens when an oceanic plate converges with a continental plate???
a trench and a mountain range with many volcanoes form
Which feature is associated with a continental-continental plate boundary???
a mountain range
At which tectonic plate boundary do pates slide horizontally past each other???
Which of the following is not associated with transform boundaries???