Download PLATE BOUNDARIES AND CALIFORNIA

PLATE BOUNDARIES AND
CALIFORNIA
Chapter 5
THE BIG IDEA
California is located on a plate boundary, where major geologic
events occur.
Lesson 1: Interactions at Plate Boundaries
 There are three main types of plate boundaries, where stresses cause rocks to
deform.
Lesson 2: California Geology
 Many of California’s landforms were produced by plate tectonic activity, which
continues today.
LESSON 1: INTERACTIONS AT
BOUNDARIES
PLATE
There are three main types of plate boundaries where stresses cause rocks to
deform.
What you’ll learn:
• Describe types of stress that deform rock.
• Relate geologic features of Earth’s surface to types of plate boundaries.
So What?!
Understanding geologic events that occur at plate boundaries can save lives and prevent
damage to property.
REVIEW VOCABULARY
Lithospheric Plate:
Large, brittle pieces of Earth’s outer shell composed of
crust and uppermost mantle.
NEW VOCABULARY
rift valley
fault
Divergent P.B.
Transform P.B.
Long, narrow valley formed as the hanging wall of a
divergent boundary slips down.
Fracture in which rocks on one side of the fracture move
relative to rocks on the other side.
Boundary formed where plates move apart
Boundary formed when two plates move sideways past
each other.
NEW VOCABULARY
fracture
continental rifting
Convergent P.B.
Break or crack in rock
Process that pulls apart a continent.
Boundary formed when two plates move toward each other.
ACADEMIC VOCABULARY
inclined
Sloping, slanting, or leaning relative to the horizontal or
vertical
The Leaning Tower of Pisa inclines about 3.99
degrees. In other words, the top of the tower is
displaced horizontally 12 ft 10 in from where it
would be if the structure were perfectly vertical.
DRIFTING CONTINENTS
Types of Rock Stress
Tension
Rocks are pulled apart;
causes stretching and
thinning of the
lithosphere.
Compression
Shear
Rocks are pushed
together; makes rock
layer thick.
Rocks are pushed in
opposite directions; neither
thickens nor thins
lithosphere
3 MAIN TYPES OF FAULTS
 Normal Fault
 Reverse Fault
 Strike-Slip Fault
SUMMARIZE IT
Rephrase the main ideas of this section in your own words.
TYPES OF PLATE BOUNDARIES
Sequence the events that occur during continental rifting.
A continent splits apart at a divergent
plate boundary.
Tension stress causes rocks to break and form
normal faults.
The hanging wall slips down and forms a rift
valley.
TYPES OF PLATE BOUNDARIES
Distinguish 3 types of convergent plate boundaries. Describe what happens at each type of boundary.
Ocean-to-Ocean
Ocean-to-Continent
Colder, denser slab is
forced down, forming a
trench; water is released
and melts rocks, forming
magma.
Denser ocean plate always
sinks below continental
plate; melting forms a string
of volcanoes along edge of
continent.
Continent-toContinent
Compression forces force
crust to rise, forming tall
mountains.
TYPES OF PLATE BOUNDARIES
Complete this paragraph about transform plate boundaries.
At transform plate boundaries, plates
Move sideways past each other
______________________________. In the ocean, these
pieces of mid-ocean ridges
boundaries connect ________________________.
large earthquakes
On the continents, _________________
can occur
along these boundaries.
SUMMARIZE IT!
Summarize three (3) main ideas of the above sections.
LESSON 2: PLATE BOUNDARIES AND
CALIFORNIA
Many of California’s landforms were produced by plate tectonic activity, which
continues today.
What you’ll learn:
• Describe California’s current plate tectonic setting and how plate movements have
produced landforms.
• Predict future changes in California’s tectonic setting and topography.
So What?!
Interactions between the North American Plate and the Pacific Plate produce California’s
mountains and basins and cause earthquakes and volcanoes.
REVIEW VOCABULARY
uplift
Any process that moves Earth’s surface to a higher
elevation.
NEW VOCABULARY
San Andreas Fault The S.A.F. is a transform boundary (and a
strike-slip fault) between the N.A. Plate and the
Pacific Plate. It extends all the way from Cape
Mendocino in the north to the Salton Sea in
the south.
ACADEMIC VOCABULARY
adjacent
Next to or very near
* The San Andreas Fault is a boundary between two adjacent
plates.
PLATE TECTONICS IN CALIFORNIA
Distinguish two plate boundaries found in California.
1. The San Andreas Fault System, a continental transform
boundary cutting across the state.
2. A convergent plate boundary offshore in the northern
part of the state.
PLATE TECTONICS IN CALIFORNIA
Identify three features of California geology caused by plate tectonics.
1. earthquakes
2. volcanoes
3. mountains
PLATE TECTONICS IN CALIFORNIA
Create a diagram showing the San Andreas Fault.
SUMMARIZE IT!
Summarize the main ideas of the above section of the lesson.
PLATE TECTONICS IN CALIFORNIA
Analyze the role of a convergent plate boundary in shaping CA geology.
The Gorda and Juan de
Fuca plates are forced
beneath the coast.
Melting above the subduction zone
produces the volcanic mountains in the
Cascade Range.
CALIFORNIA’S MOUNTAINS
Organize information about the formation of mountains in California.
I. Subduction
A. Granite rocks formed under volcanic mountains when plates
B.
converged.
An ancient oceanic plate subducted, forming rocks in several
mountain ranges.
II. Rifting
A. Tension stresses cause continental rifting.
B. Panamint Range rises as the crust stretches.
FUTURE PLATE MOVEMENTS
Summarize two changes that might occur in the future as a result of plate tectonics.
 The Pacific Plate will keep moving northwest, bringing Los Angeles and
San Francisco closer.
 Death Valley and the Gulf of California are dropping and opening up as
a result of tension stress.
SUMMARIZE IT!
Rephrase the main ideas of the lesson in your own
words.