Download Plate Tectonics worksheet

Name ___________________________
Date _________ Period 1 2 3 4 5 6
Plate Tectonics
One of the major questions with the Theory
of Continental Drift is how does it work? We
live on a dynamic Earth, in which about twenty
60-mile thick lithospheric plates move about on
the fluid upper mantle. The plates jostle with
each other, some hit each other head on, some go
under one another, and some just slide by each
other. Most of the volcanoes and earthquakes on
Earth happen where these plates meet.
Plate tectonics emphasizes that new ocean
crust is produced at the midocean ridges. This
new crust begins to spread to either side of the
ridge. As it spreads, it dives under another plate
and is subducted back into the upper mantle. At
some geologic time in the future, the recycled
crust appears again at a mid-ocean ridge.
There are three types of plate interaction
• Divergent Plate Boundaries
• Convergent Plate Boundaries
• Transform Plate Boundaries
Divergent Plate Boundaries are where plates are
moving away from each other. This movement
is found along the midocean ridges where new
crust material is being created.
•
Type II Ocean – Continental: when ocean
crust subducts under continental crust
forming mountain chains and volcanic
activity
•
Type III Continental – Continental: when
two continental plates meet and buckle up
forming large mountains.
Transform Plate Boundaries are when plates
move side by side with each other resulting in
frequent earthquakes.
Convergent Plate Boundaries are where one
plate dives (subducts) under less dense crust to
be recycled back into the asthenosphere. There
are three types of convergent plate boundaries:
• Type I Ocean – Ocean: when the ocean crust
of two plates meet usually forming island arcs
Name ___________________________
Date _________ Period 1 2 3 4 5 6
Fig 1: Global Lithospheric Plates’ Relative Motion and Speed
Data Analysis
1. Look at Fig 1: Global
Lithospheric Plates’
Relative Motion.
2. Determine what type
of plate boundary
exists between each
of the two plates in
Table 1.
3. Describe the type of
stresses that occur at
the plate boundaries
in Table 1. Use the
three choices
diagramed below.
Plate Boundary
Boundary Type
Stresses
North American Plate and the Pacific Plate near California
Nazca Plate and the South American Plate
South American Plate and the African Plate
Pacific Plate and the Nazca Plate
Juan DeFuca Plate and the Pacific Plate
Juan DeFuca Plate and the North American Plate
Australian Plate and the Eurasian Plate
North American Plate and the African Plate
Pacific Plate and the Philippine Plate
Indian Plate and the Eurasian Plate
Questions
1. Where does the overwhelming amount of seismic activity occur on the Earth’s surface?
2. Explain why the term recycling is an excellent description of plate tectonics.
3. Explain how tectonic plate movement could create another supercontinent like Pangaea.
4. If the Earth’s core provides the heat that drives plate tectonics, then what will eventually happen
as the Earth’s core cools down over billions of years?
5.
What are the various ways in which lithospheric plates interact with each other as they move
around on a dynamic Earth?