SC.912.e.6.1
Describe and differentiate the layers
of Earth and the interactions among
them.
• Earth Structures - The scientific theory of plate
tectonics provides the framework for much of
modern geology. Over geologic time, internal
and external sources of energy have
continuously altered the features of Earth by
means of both constructive and destructive
forces. All life, including human civilization, is
dependent on Earth's internal and external
energy and material resources.
9.5 Mechanism of Plate Motion
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Chapter 9: Plate Tectonics
Online Field Trips
Chapter Quiz
Study Guide Summary (PowerPoint presentation)
Web Quest: What if Pangaea Had Never Broken
Up?
• Web Resources
– Continental Drift: Links on continental drift
– Actions at Plate Boundaries: Links on plate boundaries
• Animations
Earth’s Formation
inner core
outer core
The four layers are the inner core, outer core, mantle,
and crust.
mantle
crust
lithosphere
asthenosphere
Inner Core
• solid
Outer Core
• liquid
Earth’s Formation
inner core
outer core
The four layers are the inner core, outer core, mantle,
and crust.
mantle
crust
lithosphere
asthenosphere
Mantle
• solid with liquid properties
Crust
• solid
Earth’s Formation
inner core
outer core
mantle
crust
lithosphere
The four layers are the inner core, outer core, mantle,
and crust. The crust and top of the mantle are further
classified by their properties into the lithosphere and
the asthenosphere.
Crust
asthenosphere
Lithosphere
Mantle
Asthenosphere
DAY 2
Mechanisms of Plate Motion
Describe the mechanisms of plate motion.
What drives the slow movement of the plates
and the convection in the mantle?
Mechanisms of Plate Motion
Causes of Plate Motion
 Scientists generally agree that convection
occurring in the mantle is the basic driving
force for plate movement.
• Convective flow is the motion of matter resulting from changes
in temperature.
Mechanisms of Plate Motion
Causes of Plate Motion
 Slab-Pull and Ridge-Push
• Slab-pull is a mechanism that contributes to plate motion in
which cool, dense oceanic crust sinks into the mantle and “pulls”
the trailing lithosphere along. It is thought to be the primary
downward arm of convective flow in the mantle.
• Ridge-push causes oceanic lithosphere to slide down the sides of
the oceanic ridge under the pull of gravity. It may contribute to
plate motion.
Mechanisms of Plate Motion
Causes of Plate Motion
 Mantle Convection
• Mantle plumes are masses of hotter-than-normal mantle material
that ascend toward the surface, where they may lead to igneous
activity.
• The unequal distribution of heat within Earth causes the thermal
convection in the mantle that ultimately drives plate motion.
Mantle Convection Models
Plate Tectonics
VOCABULARY
mantle convection
ridge push
slab pull
Causes of Plate Movement
Mantle convection, ridge push, and slab pull are
hypothetical models for the causes of plate
movements.
Deep-sea
trench
Mid-ocean
ridge
Deep-sea
trench
Mantle convection
This image shows one model
of how mantle convection may
contribute to plate movement.
This image shows
as section of the
East Pacific Rise, a
mid-ocean ridge.
Describe the mechanisms of plate motion.
What drives the slow movement of the plates and the convection in the mantle?
Slab- Pull: where the descending slab pulls on the plate
Ridge-Push: Force of gravity causing the cold
lithosphere to move away from the ridge by sliding
down over the asthenosphere, which gets more elevated
toward the ridge
Mantle-Convection: motion caused by flow of hot, less
dense material upwards and cold, more-dense material
downward
The unequal distribution of heat with Earth’s interior
drives plate motions
Day 3
Create a table for Causes of Plate
Motion include;
personal definition and
illustration for each motion