Download File

Section 11.1 (Part 2, Pages 360-369)
1) One theory about the formation of the continents is that all of the continents were at one time
joined together in a huge land mass, called ________________________ (which means
________________________________), and it broke apart about
______________________________ years ago.
2) The theory of ____________________________________________ suggests that the
continents change position very slowly, moving over the surface of Earth a few centimetres
every year.
3) The biological evidence for continental drift: Some similar ___________________ have been
found in areas no longer connected, and some fossils have been found where weather or land
conditions are not consistent with what that species would have needed to survive.
4) The geological evidence for continental drift: Some similar _______________ have been
found in areas no longer connected.
5) The meteorological evidence for continental drift: ________________________ (which need
rich plant life in a tropical, swampy environment to form) have been found in moderate and cold
climates.
6) New technology became available to gather evidence from the
____________________________________:
-____________________ is a sound wave technology that sends out sound waves and
then records the time that the sound waves take to bounce back. It is used to map the
_____________________ and ___________________________________________________.
Sonar revealed that many features found on the sea floor were ___________________ to
features found on land (ex: mountain ridges like the __________________________ that
stretches north to south along the middle of the Atlantic Ocean).
-_____________________________ are sensitive instruments that can detect the
direction and strength or a magnetic field. Testing showed that at some point there was a
reversal in Earth’s magnetic field and that the sea floor was ______________________.
-____________________________________________ involves core samples being
collected by drilling into the oceanic crust. Tests show that younger rock is closer to the MidAtlantic Ridge and older rock is closer to the continents.
7) These new technologies indicated that Earth’s crust is ______________________________.
8) When magma rises from an ocean ridge, the magma produces _______________________,
which pushes the plates apart. As these plates are pushed apart, other plates are pushed
together. At ____________________ boundaries, plates move away from each other. At
___________________________ boundaries, plates move toward each other.
9) A third concept of movement is that some plates are sliding past each other along a
___________________________ boundary.
10) The continental drift theory was dismissed because the _______________________ was
moving too, not just the continents. The new theory is called ____________________________
and it states that the Earth’s crust is broken up into pieces (plates) that are always moving
around on Earth’s ____________________.
11) __________________________________ are now used to measure plate movements.
12) Scientists are still not sure what causes the plates to move. One explanation is that
______________________________________ in the mantle move the plates.
13) Each plate touches several other plates, so each movement of one plate affects other
plates. When two plates collide or converge, one plate is shoved under the other. The area
where one part of the crust is forced below another part is called a
____________________________________________.