Plate Tectonics
Notes on…
Name________________________
Plate tectonics states that the Earth's _______________ and
_______________ are broken into sections called _____________.
1) These plates move around the _______________.
2) Plates are composed of the crust and a part of the upper
mantle, these two parts together are called the
_______________.
3) The layer below the lithosphere is the
_______________.
4) The lithosphere floats or _______________ around on the asthenosphere .
MAJOR IDEAS IN PLATE TECTONICS
Idea #1: ______________________________
1) Alfred _______________ first proposes Continental Drift in his book published in 1915.
2) Suggests that 200 million years ago there existed one large ______________________________ which
he called _______________ (All Land)
3) This was not really a new idea, but Wegener offered several lines of evidence in support of his
proposal:
Evidence A: ______________________________
-Wegener noted the similarity in the _______________
of North and South America and Europe and Africa.
-Today the fit is done at the ____________________
________________ and it is nearly a perfect match.
Evidence B: ______________________________
- eg ________________________, Lystrosaurus, Glossopteris
-Reptile similar to modern alligator which lived in shallow waters of ________________________and
_______________.
Evidence C: Rock Similarities
i) ______________________________found in-line across ocean basins.
ii): _____________________________________________.
Idea #2: Magnetism and ________________________________
1) Earth behaves like a _______________________________with a _______________________________ north and
south.
a) At poles a compass needle dips _______________________________
(Downward at the north pole, upward at the south pole and horizontal at the equator. )
b) Magnetic poles do not correspond with _______________________________ poles.
c) Magnetic pole moves as much as ______km per year.
2) Cause of _______________________________
•
First thought to be the result of a _______________________________core. However, it has been shown that
when any substance is heated _______________________________it loses its __________________________
magnetism.
•
Earth is a __________ - Outer core is a fluid consisting
largely of iron, so it is an excellent
_____________________. Electromagnetic currents are
generated and amplified by motion within the liquid caused
by ______________________.
•
_______________________________unifies the random
convective movements, generating the magnetic field.
3) In the 1950's scientists discover how to measure _________________
(=_______________________________ frozen in the rock at the
time it ___________).
a) With this knowledge scientists could tell the direction and
latitude of _______________________________ at the time the rock
formed.
b) Found that by 500 MY ago magnetic north was located near
_______________________________.
c) Fred Vines supports Hess with his explanation of
___________________________________ on either side of the Atlantic Midocean ridge
Types of _______________________________
1. _______________________________ = plates _______________________________at the boundaries
-Characterized by _______________________________and _______________________________.
2. Convergent = plates _______________________________
-Characterized by trenches and _____________________
-ocean plates are ___________than continental plates
SO…
a) ocean plates _____________ continental plates when they
meet (called ___________________________)
b)When two continental or two ocean plates meet, they thrust
____ into _______________________________.
Examples:
Ocean - Ocean (____________________ Islands)
Ocean - Continental (_______________________________)
Continent - Continent (_______________________________)
3. Transform= plates moving ___________________________along the boundary
-Characterized by ___________________and ___________________ (e.g. San Andreas Fault)
Additional Evidence in Support of Plate Tectonics
a) Distribution of ___________________ along plate ___________________
b) Location of earthquake foci along steeply-dipping ___________________ zones
c) Age dating ___________________ on either side of the ridge indicates the sediments get progressively
___________________away from the mid-ocean ridge axis
d) ___________________ of sediments also increases away from ridge
Driving Force Behind Plate Tectonics
1. ___________________ Cells
2. ___________________- thermal plume rises from the
___________________.
-can occur in the ___________________ of a plate
(eg., ___________________)
Theory of Plate Tectonics
Test Your Skill!
1.
Name___________________
The theory of ___________________ states that the earth’s crust and upper mantle are
broken into sections called plates.
2. These plates are composed of the crust and a part of the upper mantle. These two
parts together are called the __________________________.
3. These plates float on the __________________________.
4. Plates that move together form ________________________boundaries.
5. Plates that move apart from ________________________boundaries.
6. Plates that slide past each other form ______________________ boundaries.
7. _______________________ occurs when magma from the Earth’s mantle rise to the surface at mid-ocean ridges
and cools to form new sea floor. This occurs at _____________________ boundaries.
8. Subduction zones occur at __________________________boundaries.
9. Earthquakes tend to occur at ____________________________boundaries.
10. Volcanoes tend to occur at ____________________________boundaries.
11. Mountain ranges are formed at ______________________ boundaries.
12. The San Andreas Fault is an example of the effect of a ____________________ boundary.
13. The Himalayan Mountain Range is an example of an effect of a _____________________ boundary.
14. The Mid Atlantic ridge is being formed at a __________________ boundary.