Download Plate Tectonics Review & The Rock Cycle (11/3)

Plate Tectonics
Review
Tuesday, November 3rd 2015
Textbook pages 209-215
The Earth Is a Dynamic Planet

Three major concentric zones of the earth
 Core: solid inner part surrounded by a liquid
Mantle: mostly solid rock
 Including the asthenosphere: hot, partly melted
rock that flows and can be deformed like
plastic
 Crust
 Continental crust & Oceanic crust (71% of
crust)
Plate tectonics are responsible for Major
Features of the Earth’s Crust and Upper Mantle
The Earth beneath your feet is
moving…….
 Tectonic
Plates: huge rigid plates move
extremely slowly atop the denser mantle on
hot, soft rock in the underlying
asthenosphere
 Convection cells: move large volumes of
rock and heat in loops within the mantle like
gigantic conveyer belts
The Earth beneath your feet is
moving…….

Plate tectonics = movement of lithospheric
plates

Heat from Earth’s inner layers drives convection
currents

Pushing the mantle’s soft rock up (as it warms) and
down (as it cools) like a conveyor belt

Continents have combined, separated, and
recombined over millions of years (Pangaea = all
landmasses were joined into a supercontinent 225
million years ago)
The Earth’s Crust Is Made Up of a Mosaic
of Huge Rigid Plates: Tectonic Plates
The Earth’s Major Tectonic Plates
EURASIAN PLATE
JUAN DE
FUCA PLATE
NORTH
AMERICAN
PLATE
CARIBBEAN
PLATE
ANATOLIAN
PLATE
CHINA
SUBPLATE
AFRICAN
PLATE
PACIFIC
PLATE
COCOS
PLATE
NAZCA
PLATE
Divergent plate boundaries
PACIFIC
PLATE
SOUTH
AMERICAN
PLATE
SOMALIAN
SUBPLATE
SCOTIA
PLATE
PHILIPPINE
PLATE
ARABIAN
PLATE INDIA
PLATE
AUSTRALIAN
PLATE
ANTARCTIC PLATE
Convergent plate
boundaries
Transform faults
Fig. 14-4, p. 347
Three types of boundaries between plates

Divergent plates – plates move apart
 Magma – flows up through the resulting cracks forms
new rocks (seafloor spreading)
 Oceanic ridge – some of
which have higher peaks
and deeper canyons than
earth’s continents
Three types of boundaries between plates

Convergent plates – two plates collide
 Oceanic & Continental: oceanic plate slides under the
continental crust (subduction)

Magma erupts through the surface in volcanoes as a result
of subduction
Continental & Continental:
crust may lift up from both
plates (uplift) to form
mountains
 Trench: forms at the
boundary between the 2 converging plates

Creation of a Volcano
Volcanoes Release Molten Rock
from the Earth’s Interior

Volcano: magma reaches the earth’s surface through a
fissure (crack)
 Lava: magma that reaches the earth’s surface.
Debris ranging from large chunks of larva rock to
glowing hot ash, liquid lava and gases such as water
vapor, carbon dioxide and sulfur dioxide.
 Much of the world’s volcanic activity is concentrated
along the boundaries of the earth’s tectonic plates
 Benefits of volcanic
activity: highly fertile soil,
creates outstanding
landforms (Crater Lake, OR)
Three types of boundaries between plates

Transform fault boundary (e.g. San Andreas
fault): where plates slide and grind past one
another along a fault (fracture in the rock)


Fault zones are where movement has occurred
Most located on the ocean floor
The San Andreas Fault as It
Crosses Part of the Carrizo
Plain in California, U.S.
Earthquakes Are Geological
Rock-and-Roll Events
Earthquake – occur when rocks rupture
(epicenter) unexpectedly along a fault (seismic
activity)
Seismic waves – waves of energy
Magnitude – measures the size of the
earthquake as it relates to the amplitude of
the energy wave & distance
Richter scale
Insignificant: <4.0
Foreshocks and aftershocks
Minor: 4.0–4.9
Primary effects of earthquakes: shaking,
Damaging: 5.0–5.9
permanent vertical or horizontal
Destructive: 6.0–6.9
displacement of the ground
Major: 7.0–7.9
Great: >8.0
Major Features and Effects of an
Earthquake
Areas of Greatest Earthquake
Risk in the United States
Areas of Greatest Earthquake
Risk in the World
Earthquakes on the Ocean Floor
Can Cause Huge Waves Called
Tsunamis


Tsunami, tidal wave: generated when part of the
ocean floor suddenly rises or drops. Usually occurs
offshore in subduction zones.
Detection of tsunamis: by ocean buoys, pressure
recorders on the ocean floor which measures
changes in water pressure as the waves pass over it;
data relayed via satellites tsunami warning systems
Some Parts of the Earth’s Surface
Build Up and Some Wear Down


Internal geologic processes
 Generated by heat from the earth’s interior,
generally build up the earth’s surface in the form
of continental and oceanic crust including
mountains and volcanoes
External geologic processes
 Weathering : driven directly or indirectly by
energy from the sun(mostly in the form of
flowing water and wind)
 Physical, Chemical, and Biological
 Erosion: Wind, Flowing water, Human activities
Weathering: Biological, Chemical,
and Physical Processes
Earth’s Major Geological Processes
and Hazards

Gigantic plates in the earth’s crust move very slowly
atop the planet’s mantle, and wind and water move
the matter from place to place across the earth’s
surface.

Natural geological hazards such as earthquakes,
tsunamis, volcanoes, and landslides can cause
considerable damage.
Earth’s Rocks are Recycled……..

The three major types of rocks found in the earth’s
crust — sedimentary, igneous, and
metamorphic — are recycled very slowly by the
process of erosion, melting, and metamorphism.
There Are Three Major Types of
Rocks


Earth’s crust is composed of minerals and rocks
Three broad classes of rocks, based on formation
Sedimentary
Igneous
Sandstone
Granite
Shale
Lava rock
Dolomite
Metamorphic
Slate
Anthracite
Lignite
Slate
Bituminous coal
Marble
Leave space under each rock type for in-class and homework notes!
The Earth’s Rocks Are Recycled
Very Slowly

Rock cycle: the
interaction of
physical and
chemical
processes that
change rocks
from one type to
another. Slowest
of the earth’s
cyclic processes
The Life of a Rock
Layers of
sediment join
together.
Igneous
Melted rock
cools and
hardens
Sedimentary Rock
Changes are made
from pressure and
heat.
Metamorphic
Rocks become smaller, and
smaller, and smaller, and
...
smaller







By erosion
By wind
By earthquake
By floods
By rain
By slides
By man
Rocks
change…………..



By earthquakes
By volcanoes
By heat and pressure
 Weathering:
the breaking up of rocks
and soil into different products (clay, sand,
rock fragments like pebbles & stones)
 Erosion:
the moving of weathered rock
and soil. Weathering allows erosion to
take place.
Sedimentary Rock is . . .

Rock formed when layers of small particles of
shell, rock, and sand join together.
Types of Sedimentary Rocks
Include…
Conglomerate
Sandstone
Gypsum
Shale
Limestone
Sedimentary Rocks
How They are Made




Wind and water break down the earth
Bits of earth settle in lakes and rivers
Layers are formed and build up
Pressure and time turn the layers to rock
Metamorphic Rock is . . .

Rock that is formed when pressure and heat create
changes to sedimentary or igneous rock.
Types of
Metamorphic
Rocks
Metamorphic Rocks
What are They?
Rocks that have changed
 They were once igneous or sedimentary
 Pressure and heat changed the rocks

Igneous Rock is . . .
 Rock
that is formed when melted rock
cools and hardens.
Types of Igneous Rocks
Granite
Igneous Rocks
What are They?
Fire Rocks
 Formed underground by trapped, cooled
magma
 Formed above ground when volcanoes
erupt and magma cools

With your group, share your rock type posters.
Take notes on each type in your notebook –
including your own!
 After you’ve shared, complete the Rock Cycle
Activity.
