DO NOW
1. Get out your Plate Boundary Types HW
2. Work on the Plate Boundary Synopsis
Activity (back of hw) while you wait for
your stamp/the start of notes
3. List and draw arrow representing the 3
types of plate boundaries
Paleomagnetism
• Evidence of magnetism in rocks
• Earth has a magnetic field or invisible lines of
force
How does a compass work?
How does a compass work? Rocks contain iron
Magnetite
rich minerals called _____________________.
As rocks cool, minerals align in direction
Parallel
_________________________
to magnetic
field. These minerals become
__________ or
Frozen
locked in this position. Draw what this would
look like using different colors.
Paleomagnetism
Paleomagnetism
• Magnetized rocks act like a Compass
______________by
needle
pointing towards magnetic poles. Different
________ time
Different
periods contain __________magnetic
pole
Rocks
positions. _______can
tell us location of magnetic
poles of certain time periods.
Have the pole positions always been
the same?
Pole Reversal - rocks can tell us about pole
reversals if the magnetism is switched or
reversed
Normal Polarity
Reversed Polarity
Where N & S are
today
Opposite of where N
& S are today
Earthquake Patterns
• Occur as oceanic crust is subducted below
continental crust
(Color with Red Pencil)
Seafloor Spreading & Ocean Drilling
• age of sediments ______________________
Increase
as distance from ocean center or mid-ocean
ridge increases
Seafloor Spreading & Ocean Drilling
Seafloor Spreading & Ocean Drilling
older
• D crust _____________than
A crust BECAUSE
further away
D crust is __________________
from
spreading center of ocean where new crust is
forming!
Older
• ___________________
crust near continents
Younger
• ____________________
crust near spreading
centers
Hot Spots
• As plates move over hot spot of magma,
volcanoes are formed, new crust is created
Hawaii
• EXAMPLE = _________________
• Older Islands move away from hot spot and
begin to erode over time thus becoming
smaller
Hot Spots
Hot Spots
Which island in this chain is the oldest?
Kauai
________________
Which island in this chain is the youngest?
Hawaii
______________