Download Ch 9 ES Website-Coon - Sonoma Valley High School

Chapter 9: Plate Tectonics
continental drift
Wegener's hypothesis
that all continents were
once connected in a
single large landmass
that broke apart and
drifted slowly to their
current positions.
Pangaea
the large "supercontinent”
that is believed to have
connected all of the
continents on earth about
225 million years ago
Evidence for Continental Drift Hypothesis
 The continental puzzle –
continents fit together like a
puzzle
 Matching fossils – fossil evidence
for continental drift includes
several fossil organisms found on
different continents.
 Rock type and structures – rock
evidence for continental drift
exists in the form of several
mountain belts that end at one
coastline, only to reappear on a
landmass across the ocean.
 Ancient climates – ancient
climate evidence supported
continental drift
plate tectonics
the theory that the earth's
outer shell is composed of
a number of large plates, or
slabs of rock, whose
constant movement
explains earthquakes and
volcanic activity.
Plate tectonics :
chapter 9.3 & 9.4
tectonic plate
a large section of Earth's
lithosphere that moves
around on the
asthenosphere.
Convection currents
 Convection currents occur when a gas or a liquid is heated
from the bottom.
 Warm gasses & liquids are less dense than cold.
 The warm substance rises and the cold sinks.
 This process is responsible for air, ocean, & mantel
currents.
Pair share:
what lab did
we do that
demonstrated
convection
currents?
Convection currents
 Convection currents occur when a gas or a liquid is heated
from the bottom.
 Warm gasses & liquids are less dense than cold.
 The warm substance rises and the cold sinks.
 This process is responsible for air, ocean, & mantel
currents.
Pair share:
what lab did
we do that
demonstrated
convection
currents?
Convection currents
 Convection currents occur when a gas or a liquid is heated
from the bottom.
 Warm gasses & liquids are less dense than cold.
 The warm substance rises and the cold sinks.
 This process is responsible for air, ocean, & mantel
currents.
Pair share:
what lab did
we do that
demonstrated
convection
currents?
Types of Plate Boundaries
 The three main types of boundaries are convergent,
divergent, and transform fault boundaries.
Divergent Boundaries
 in divergent boundaries
plates move apart
 Most divergent
boundaries are located
along the crests of
oceanic ridges.
seafloor spreading
 The process by which
plate tectonics produces
new oceanic lithosphere
at ocean ridges
Convergent Boundaries
 Convergent Boundaries – two tectonic plates move
TOGETHER
Convergent Boundaries
 Oceanic – Continental
 When a continental plate
converges with an oceanic
plate, the more dense
oceanic plates subducts
under the continental plate
 Continental volcanic arc /
volcanic activity is caused
by the subduction of the
oceanic crust melting
below when it sinks into
the asthenosphere.
Convergent Boundaries
Oceanic – Continental plate boundary
Convergent Boundaries
Continental- Continental
the collision of the two
continental plates form
complex mountains.
ex: Himalayan Mountains
Convergent Boundaries: Continental-Continental
subduction zone
 A destructive plate margin where oceanic crust is being
pushed down into the mantle beneath a second plate
subduction zone
 A destructive plate
margin where oceanic
crust is being pushed
down into the mantle
beneath a second plate
trench
A surface feature in the seafloor produced by the descending
plate during subduction
Transform Boundaries
At a transform plate
boundary, plates grind
past each other without
destroying the
lithosphere.
Ex: San Andreas Fault
Transform Boundaries
At a transform plate
boundary, plates grind
past each other without
destroying the
lithosphere.
Ex: San Andreas Fault
Earth Science – Chapter 9.2
Earth Science – Chapter 9.2
Earth’s Major Plates
Types of Plate Boundaries Quiz
Types of Plate Boundaries Quiz
volcanic island arc
 A chain of volcanic
islands generally located
a few hundred miles
from a trench where
subduction of one
oceanic slab beneath
another is occurring