Download answer key

KEY
SEPUP UNIT D: PLATE TECTONICS
Study guide
1. Define the following terms:
Pangaea
A super continent that existed until about 230 million
years ago when it began to move apart
Continental
Drift
The idea that continents are moving away from each
other
Transform
boundary
Two plates sliding past each other in parallel but opposite
directions
Divergent
boundary
Two plates spreading apart
Convergent
boundary
Two plates colliding together
lahar
Mudflows that result from the shifting and sudden heating
of a volcanic eruption that melts the surrounding snow
and ice
2. What is subduction?
Subduction is the sinking of one tectonic plate under
another tectonic plate.
3. At what type of plate boundary does subduction occur?
Subduction occurs at a convergent plate boundary with typically
two oceanic plates or an oceanic and continental plate.
4. Why do geologists, or scientists who study the forces and shape of the earth have such a hard
time predicting when earthquakes will occur? Explain:
Geologists don’t know how much pressure or strain is occurring at each
fault/plate boundary. Without knowing this, predicting plate movement to
relieve the pressure is difficult.
5. Use the circle below to draw a diagram of the earth's interior by:
a. Sketching the approximate size of each layer
b. Labeling each layer with its name, make up (ie: solid, molten/liquid, solid and
molten/liquid) and composition (rock, metal)
Mantle/
solid
upperliquid
lower/
rock
Lithosphere/
solid /rock
/upper 100km
of the crust
and mantle
Crust/
solid/ rock
Inner Core/
solid/ metal
Outer
Core/
liquid/
metal
6. In your own words, explain (be specific):
a. the theory of Plate Tectonics
The theory that the surface of the earth is made up of several giant
lithospheric plates that are in constant motion. The plates are moving
because of convection currents in the mantle beneath the plates.
b. the type of evidence Alfred Wegener used to support his ‘Continental Drift’ hypothesis?
Mountain ranges, similar glacial striations (scraping), and fossilized plant
and animal discoveries were used to ‘piece together’ the continents and
their movement
7. Describe how each of these types of volcanoes are created
Shield volcano
Cinder Cone volcano
Large, broad volcanoes.
Smallest of the volcanoes.
Formed by releasing fast
Formed from explosive
moving, less gassy lava which eruptions that shoot lava into
is less explosive and more
the air. This falls back down
runny.
as cinder sized rocks forms
the cone shape.
Composite (strato) volcano
Explosive eruptions because
of gassy magma. They are
formed from layers of lava,
cinders, and ash.
8. Why is there such a high risk for earthquakes on the Pacific coast of the USA?
The pacific plate is striking against/ converging on the north American
plate
9. Scientists believe that Earth’s magnetic field is a result of the movement of the liquid metal
outer core against the movement of the solid metal inner core.
Is this a true or false statement? True