Unit at a Glance
Chapter 7: Plate Tectonics
Standards
S6E5: Students will investigate the scientific view of how the earth’s surface is formed.
a. Compare and contrast the Earth's crust, mantle, and core including temperature,
density, and composition.
d. Recognize that lithospheric plates constantly move and cause major geological
events on the Earth's surface.
e. Explain the effects of physical processes (plate tectonics, erosion, deposition,
volcanic eruption, gravity) on geological features including oceans (composition,
currents, and tides).
Unit Vocabulary
Crust: the thin, solid, outermost layer of the Earth above the mantle.
Mantle: the layer of rock between the Earth’s crust and core that makes up 67% of the Earth’s
mass.
Core: the central part of the Earth below the mantle that is made of mostly iron.
Lithosphere: the solid, outer layer of the Earth that is made of the crust and the rigid upper part
of the mantle.
Asthenosphere: the soft “plastic” layer of the mantle on which the tectonic plates move.
Mesosphere: the strong, lower part of the mantle between the asthenosphere and the outer
core.
Tectonic Plate: a block of lithosphere that moves around on top of the asthenosphere.
Continental Drift: the hypothesis that states that the continents once formed a single landmass
(ex. Pangea), broke up, and drifted to their present locations.
Sea-Floor Spreading: the process that takes place at mid-ocean ridges by which new oceanic
lithosphere forms as magma rises toward the surface and solidifies.
Plate Tectonics: the theory that explains how large pieces of the Earth’s outermost layer, called
tectonic plates, move and change shape.
Convergent Boundary: where two tectonic plates collide.
Divergent Boundary: where two tectonic plates separate or divide.
Transform Boundary: where two tectonic plates slide past one another horizontally.
Convection: the process of moving rock layers by heating and cooling.
Deformation: the process by which rocks change shape because of tectonic plate stress.
Unit at a Glance
Compression: stress that occurs when forces act to squeeze rocks. Occurs at convergent
boundaries.
Tension: stress that occurs when forces act to stretch rock. Occurs at divergent boundaries.
Folding: the bending of rock layers due to stress.
Fault: a break in rocks along which one block slides relative to the other.
Normal Fault: a fault in which the hanging wall moves down relative to the footwall. Occurs at
divergent boundaries.
Reverse Fault: a fault in which the hanging wall moves up relative to the footwall. Occurs at
convergent boundaries.
Strike-Slip Fault: a fault in which opposing forces cause rock to break and move horizontally.
Occurs at transform boundaries.
Uplift: the rising of regions of the Earth’s crust to higher elevations.
Subsidence: the sinking of regions of the Earth’s crust to lower elevations.
Essential Questions
1. What are the different layers of the
4. What are the three types of tectonic
Earth?
plate boundaries and their direction of
movement?
2. What are tectonic plates?
5. What forces are thought to be
responsible for tectonic plate movement?
3. How does sea-floor spreading and
6. How does tectonic plate movement
subduction help to explain Wegner’s
deform the Earth’s crust?
Theory of Continental Drift?