Name: ____________________________________ Class: _______________ Plate Tectonics Notes
Do Now #1:
EQ’s: 1. _______________________________________________________________________
2. _______________________________________________________________________
Inside the Earth
• The earth is
classified two
different ways:
• 1. By
chemical
composition
• 2. By physical
properties
Chemical
Composition
• The
composition of
the earth is divided into the crust, mantle, and core.
• The ___________ is the outermost layer of the Earth. It is very thin, and makes up less than
1% of the earth’s mass.
• The ___________ is between the crust and the core. It makes up 67% of the earth’s mass. It
is made of ________________.
• The _________ is in the center of the earth, and makes up 33% of the earth’s mass. It is
made of Iron, Nickel, and a little Sulfur.
Physical Properties
• The physical properties of the earth are divided up differently.
• The ______________ is the outermost layer. It is made up of the crust and the upper part of
the mantle. This layer makes up the tectonic plates.
• Oceanic Crust and Continental Crust have different properties.
• Oceanic Crust is made of ___________. It is only 5-7 km thick, but is denser.
• Continental crust is made of _____________. It is 10-70km thick.
• The Asthenosphere is a soft layer of the mantle.
• Pieces of the lithosphere move over this layer.
• It is made of solid rock that can _____________ very slowly, like putty!
• The _____________ is the strong, lower part of the mantle. It extends down to the core.
• The ___________ Core is a ___________ layer of the core. It is mostly liquid iron and nickel.
• The ____________ Core is ____________ and dense, and is also mostly iron and nickel.
Do Now #2:
- Use the
evidence
(symbols) on the
continents and
islands to
reconstruct
Pangaea, the
supercontinent.
- Identify what you
should look for to
determine which
continental
boundaries should
be joined.
- Using the
physical shape of
continents, age of
rock layers,
fossilized desert
belts,
and the
distribution of
fossils, fit together
the continents and
islands.
- Not all the
boundaries may
touch and that
there might be
areas of water
separating some
of them.
- Glue them onto
the world map.
Tectonic Plates
• The earth is divided into many tectonic plates. These lithospheric plates float on top of the
asthenosphere, and are in constant motion.
• What we know as fact now had a difficult journey into scientific knowledge.
Continental Drift
• Continental Drift is the theory that _________________ can drift apart from one another.
• Alfred Wegener studied the ___________ _______ of the continents, especially South
America and Africa, and thought maybe they had been together.
• Wegener also studied __________ across the continents.
• He found similar species spread across great distances, and wondered how the animals and
plant could travel so far.
• The answer was that the animals and plants did not travel, the __________ did!
• The continents used to be _______________, and had now spread apart.
Pangaea
• Wegener’s evidence pointed to one, large continent called Pangaea, which is Greek for
“_______ _____________.”
• The single ocean around it was called Panthalassa, for “_________ __________.”
• There was further evidence found in mountain ranges and glacial deposits.
• Wegener said the continents moved apart…but what made them move?
• Wegner published his ideas about continental drift in 1915, but they were met with hostility.
• There was no way scientists of the time could picture giant continents plowing though oceans
to move.
• For now, his ideas had to wait for science to catch up.
Do Now #3: K-W-L
What you Know already
What you Want to know
What you Learned
Earth’s Magnetic Field
• The Earth emits a ___________________________.
• Caused by the spinning of the __________________.
• The movement of iron and nickel the magnetic pole move over time.
• Paleomagnetism is the study of earth’s _______________ __________ over time
• Many minerals in magma are magnetic
• They align themselves ___________________
• Magma cools, forms rock and the minerals are locked in a north-facing position
• Scientists can use this as an arrow to finding the ____________ in the ___________.
• Evidence for Continental Drift was also found looking at magnetic drift. When the magnetic
rocks were mapped on the current position of the continents, they did not add up. When the
continents were moved to their Pangaea locations, they did!
• On top of the magnetic poles wandering on earth, another strange thing happens.
• Over time, the magnetic field will ___________, and then ________________!
• This means the north and south poles switch places.
• It is like holding a magnet and then turning it upside down.
Sea Floor Spreading
• When the magnetic field switches, the minerals face the ____________________
• The crust contains ‘stripes’ of alternating north and south facing minerals
• Discovered by a research team from the Coast Guard and Scripps in 1955
• Called ________________________________
• The stripes _______________ each other in length and age.
• There was also a _________________________________, and the rocks got __________ as
you went further from the center
• During WWII, Naval Ships noticed something big in the middle of the Atlantic Ocean.
• Where the ocean was once considered to be flat and barren, the ships saw large
_________________.
• These mountains are called the Mid-Atlantic Ridge.
• In 1963, geologists Frederick Vine and Drummond Matthews put together the observations of
large mountain ranges with new rock, polarity strips, and matching older rock patterns
together.
•
•
•
•
•
•
•
They said that new rock was ____________ in between tectonic plates at the mid-ocean
____________. It then gets pushed away, and more new rock forms.
This idea was called Sea Floor Spreading.
These ridges are the site where sea floor spreading takes place.
Sea Floor Spreading is the process that where new plates are created as the two plates pull
away from each other and _________________.
Magma rises and cools between the plate gaps, forming new rock.
This makes rocks close to the ridge _________, and rocks further from the ridge
______________.
Now Wegener had a way to move the continents! It’s too bad he died in 1930. 
Convection Currents
• Convection currents within the mantle create movement
• ____________________________________________________
• ____________________________________________________
• Creates _________________ rotation of the mantle
• This pushes & pulls the plates from one place to another
Label the tectonic plates on the map below.
Closure
1. What two ways is inside the earth
classified? How do the two compare?
3. What evidence is there for seafloor
spreading?
2. What evidence supports continental drift?
4. What is moving our tectonic plates?