Unit 10—Earth Science
Chapter 28 The Changing Earth
Name________________________________
Lab 28.2 Plate Tectonics
In this investigation, you will identify the tectonic plates of Earth’s lithosphere, learn which geologic
features are associated with the boundaries of plates, and predict what Earth will look like in 50 million
years.
The theory of plate tectonics states that large pieces of Earth’s lithosphere called tectonic plates move
over the surface of the earth. At the plate boundaries, plates move apart, collide, or slide past one
another. As a result of this movement, new features emerge on Earth’s surface. We know Earth is 4.6
billion years old. In this investigation, you will identify Earth’s tectonic plates and predict the future
movement of these plates.
Part 1—Reading a bathymetric map
A bathymetric map shows what land looks like under a body of water like the ocean.
1.
Find examples of the following features on your bathymetric map: mid-ocean ridges, rises, and
deep ocean trenches. Some mid-ocean ridges are labeled as rises (i.e., the East Pacific Rise). List
one example of each from your map in the second column in the table below.
2. In the third column, list which kind of plate boundary is associated with each feature. The map
on the last page of this lab may help.
3. In the fourth column, there are small diagrams showing two plates and the boundary between
them. Draw arrows showing how the plates move relative to each other at these boundaries.
Features
Examples from the
map
Kind of plate boundary
(convergent or
divergent?)
How do the plates move
at this boundary?
Plate 1
Plate 2
Plate 1
Plate 2
Plate 1
Plate 2
mid-ocean ridge
rise
deep ocean trench
Unit 10—Earth Science
Chapter 28 The Changing Earth
Part 2—Finding plate boundaries
1.
Earth currently has 15 tectonic plates, 7 major and 8 minor. Using the features on the sea floor
as illustrated on the bathymetric map, and the map on the last page of this lab, draw in and
label the 15 tectonic plates on the laminated bathymetric map. Note that the bathymetric map
and the map on the last page of the lab don’t break at the same longitude. Use overhead
marker to write on the bathymetric map.
2. In order to accurately and successfully accomplish #1, here are a few guidelines;
a. Mid-ocean ridges, rises, and deep ocean trenches are found at plate boundaries.
b. Earthquakes are common along plate boundaries. See the map of frequent earthquakes
below (“Preliminary Determination of Epicenters”).
c. Mountain ranges often occur at convergent plate boundaries. A globe will help in
locating the Himalayan Mountains, which form a plate boundary
Part 3—Movement of the plates
1. Now that all plates have been drawn and labeled, use a different color of overhead marker to
draw an arrow in the middle of each plate to show the direction of movement of the 15 plates.
The map on the last page will help with this.
a. (Circle one) Plates move (apart, together) at trenches and mountains.
b. (Circle one) Plates move (apart, together) at ridges and rises.
c. When your map is completed, show it to me and have me initial here._______________
Unit 10—Earth Science
Chapter 28 The Changing Earth
2. We will assume that in 50 million years the plates will move about 3% from their current
positions, continuing in their current direction. This means that each plate on the bathymetric
map will move about 1.5 cm. Some further guidelines;
a. At boundaries with trenches with one oceanic plate and one continental plate, the
oceanic crust subsides.
b. When continents converge, neither can subduct, so mountains form.
3. Some of the oldest records of mankind come from the Middle East and Northern Africa. What
has become of this “Cradle of Civilization” 50 million years into the future?
4. What has become of China, the islands of the western Pacific Ocean, and Australia?
5. Where will the longest mountain range be located 50 million years from now?
6. List 5 other changes in store for Future Earth as indicated by your map.
a.
b.
c.
d.
e.
7. Earlier in this lab, it was stated that Earth currently has 15 tectonic plates. Explain why
“currently” is used in this statement.
**When you
have finished #7,
use a damp
sponge to wipe
your map off.
Gently blot it dry
with paper
towel. Have me
initial here.
______________
Unit 10—Earth Science
Chapter 28 The Changing Earth