Transcript Chapter 17 Review game

What was Wegener’s hypothesis called?
Continental drift
Which two continents seemed to fit
together so well and supported the
continental drift theory?
Africa and South America
What are two pieces of evidence that
Wegener had to support his drift
theory?
The Shape of the Continents
Coal in Antarctica
Matching rock types on the coasts
Matching Fossils on the coasts
List and describe the two technologies that Wegener
could have used to support his drift theory but didn’t
have available at the time?
Magnetometer: Pale magnetism showed that the
seafloor was spreading
Sonar: Showed that the seafloor was not flat
Why was Wegener’s theory rejected?
He didn’t have a “Driving Mechanism” for how the
continents can move.
What idea about the ocean floor did
Sonar help disprove?
The old idea was that the seafloor was flat. The
sonar showed that it had mountains and trenches
(not flat at all!)
How do sediments close to the ridge
vary from sediments far from the ridge?
Sediments close to the ridge are younger and make
thinner layers.
What is the difference between normal
and reversed polarity?
Normal is today’s magnetic field orientation and
reverse is the opposite.
Briefly explain plate tectonics?
The Earth’s upper crust is broken into large slabs
called “Plates”. These plates move around due to
convection cells that are occurring underneath them
in the Mantle. These plates interact with each other
at plate boundaries. There are frequently volcanoes
and earth quakes at these boundaries.
Briefly explain how the continents move?
The continents (Thick slabs of granitic crust) are
riding on top of the ocean crust (thinner more dense
layer of basalt). As the new ocean crust forms at
divergent plate boundaries, the old crust is pushed
away and the continents go along for the ride.
Compare and contrast the three types of convergent
boundaries?
Ocean to ocean (Subduction zones form)
Ocean to continental (Subduction zones form)
Continental to Continental (Mountain building)
Early map makers thought continents might have
moved based on their observations of…?
Matching coast lines
What was the name of all of the continents stuck
together?
Pangaea
What two technologies could Wegener not use
because it was invented yet?
Sonar and magnetometer
True or False, land dwelling animals such as
Cynognathus and Lystrasaurus were apart of the
fossil evidence that Wegener used?
True
What did the fresh water reptile fossils indicate to
Wegener?
Since they were found on the coasts of South
America and Africa, and because the animal could
not swim across such a vast distance, that the two
coasts must have been much closer
Based on the Glossopteris fossils,
Wegener concluded what?
Since these fossils were found in South America,
India and Antarctica, it was unlikely that an area that
large had a single climate. He also reasoned that this
plant required a more temperate climate, so areas
like Antarctica must have been closer to the Equator.
Besides the Glossopteris plant fossil, what was found
in Antarctica that lead Wegener to believe it was
once near the equator?
Coal
What made Wegener think that landmasses drifted
away from the south pole?
Glacial deposits, because at the current location
for areas like Africa, India and Australia, it is too
warm for glaciers like that to form.
Why did most scientists reject
Wegener’s hypothesis?
He couldn’t explain how a continent could move.
Additionally, a continent made of granite could
not push through a sea floor of basalt without
breaking up.
What uses sound waves to measure depth?
Sonar
Maps made from Sonar and
data led to the discovery of
ocean ridges and deep sea trenches?
Magnetometer
What is the study of the magnetic record preserved
in the Earth’s rocks called?
Paleomagnetisim
True or False, earthquake activity and volcanism are
common along ocean ridges?
True
What theory explains that the Earth’s continents
move because they ride atop ocean crust as it
moves away from ocean ridges?
Seafloor Spreading
What is an isochron?
An Isoline that connects areas of equal age.
What happens to the thickness of sediments as
distance from the mid ocean ridge increases?
Why does this happen?
The thickness increases because more time has
gone by since the crust has been made so more
weathering has taken place.
Where is the youngest rock in the ocean located?
At the ridges (divergent plate boundaries) where
the new crust is made.
What does it mean if an area has a reversed
polarity?
It has the opposite polarity of today
Minerals containing
acts like a small compass
inside the rock, and records the Earth’s fields over
time?
Iron
Which theory states that Earth’s crust and rigid upper
mantle move in different directions and at different
rates over Earth’s surface?
Plate Tectonics
Tectonic plates interact at places called plate
Boundaries
?
Areas where plates move apart are called
Divergent
?
Where are most divergent boundaries found?
The ocean floor
What occurs along divergent boundaries?
New crust forms, and there are ridges that form due
to the heated crust.
The mid ocean ridge is an example of what kind of
boundary?
Divergent
Places where plates come together are called?
Convergent plate boundaries
How are convergent boundaries classified?
Ocean to ocean
Ocean to continental
Continental to continental
What type of igneous rock is the ocean crust made
of?
Basalt
What is created when two ocean plates converge?
Subduction Zones
What can form if an eruption occurs at when two
ocean plates converge?
Volcanically formed islands called Volcanic island
arcs
At which boundary will a rift valley form?
Divergent plate boundary
At which boundary will a trench form?
Convergent
At which boundary do the plates slide past each
other?
Transform
What is the transfer of thermal energy called that
moves the plates?
Convection
Where does ridge push occurs?
Divergent plate boundaries (or ridges)
Where does slab pull occur?
Convergent plate boundaries or subduction zones
What is slab pull similar to at home?
When part of the comforter slides off of the bed and
it pulls the rest of it off and on to the floor.
What does asthenos mean in Greek?
Weak