Transcript Introduction to Earth*s Systems and Earth Science

Introduction to Earth’s Systems and Earth Science
Plate Tectonics Review
Tuesday, September 20th, 2016
Textbook pages 209-215
Earth and our Solar System
3rd
• _________
planet from the Sun
life
*only planet that can support _______________
elliptical
*orbits the Sun in an ____________
pattern/shape
365
*takes ________
days to complete one orbit
24
*takes _____
hours to complete one rotation
4.6
*was formed _______
billion years ago
EARTH’S INTERACTIVE COMPONENTS
LITHOSPHERE = makes up the Earth’s
interior (rock)
ATMOSPHERE = makes up the gases
surrounding Earth (air)
HYDROSPHERE= makes up the areas
of water
BIOSPHERE = makes up all the living
things within the other
parts
EARTH IS AN INTEGRATED SYSTEM OF
4 INTERACTING COMPONENTS
HOW EARTH FORMED
- CAME FROM COSMIC DUST IN THE SOLAR SYSTEM (BIG BANG
THEORY)
- ALL THE ELEMENTS FOUND ON EARTH ARE AS OLD AS EARTH
- EARLY EARTH WAS A HOT, MOLTEN SPHERE
- AS MOLTEN MATERIAL COOLED, THE ELEMENTS SEPARATED INTO
LAYERS BASED ON MASS (HEAVY IRON TOWARDS THE CENTER)
https://www.youtube.com/watc
h?v=BBwqendK8zc
EARTH LAYERS
BECAUSE EARTH’S ELEMENTS SETTLED INTO PLACE
BASED ON MASS…… EARTH IS DIVIDED INTO LAYERS
2 GROUPS OF LAYERS:
COMPOSITIONAL LAYERS
&
PHYSICAL LAYERS
KNOWLEDGE OF EARTH’S LAYERS
*SEISMIC WAVES ANALYSIS
*LAVA ANALYSIS
*METERITE COMPOSITION
COMPOSITIONAL LAYERS OF EARTH: three
major concentric zones of the earth
CRUST = thinnest (only 0.5% of earth’s
total mass), outermost layer, solid,
brittle, coolest layer, mostly oxygen,
oceanic (71%) & continental
MANTLE = Mostly solid rock, medium
density, has magma that circulates in
convection cells. Mostly iron,
magnesium, aluminum
Includes the asthenosphere: hot,
partly melted rock that flows and can
be deformed like plastic
CORE = innermost layer
(solid surrounded by liquid)
greatest density, hottest,
mostly iron and nickel
PHYSICAL LAYERS OF EARTH
1. LITHOSPHERE = outer layer, includes crust
and uppermost mantle,
divided into tectonic plates
2. ASTHENOSPHERE = middle part of mantle,
flexible, rock flows slowly
3. MESOPHERE = lower part of mantle
4. OUTER CORE = outer part of core, dense liquid
nickel and iron
5. INNER CORE = inner most part of core, dense
solid nickel and iron due to
pressure, over 4000 ° C
Comparison of the Compositional and Physical Layers:
The compositional layer is defined by the chemical composition of the layers and the
physical layer is defined by the layers’ physical properties (solid, liquid, or how waves move
through the layer).
Physical Layers
What is plate tectonics?
If you look at a map of the world, you may notice that some of
the continents could fit together like pieces of a puzzle.
• The Earth’s crust is divided into 15 major plates which
are moved in various directions.
• This plate motion causes them to collide, pull apart, or
scrape against each other.
• Each type of interaction causes a characteristic set of
Earth structures or “tectonic” features.
• The word, tectonic, refers to the deformation of the
crust as a consequence of plate interaction.
Plate tectonics are responsible for Major Features
of the Earth’s Crust and Upper Mantle
World Plates
What are tectonic plates made of?
•Plates are
made of rigid
lithosphere.
The lithosphere is
made up of the crust
and the upper part of
the mantle.
What lies beneath the tectonic plates?
• Below the lithosphere
(which makes up the
tectonic plates) is the
asthenosphere.
• The plastic layer below the lithosphere
• The plates of the lithosphere float on the
asthenosphere
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
http://www.hhmi.org/biointeractive/plate-tectonics
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)
Island Arc Formation & The “Ring of Fire”
http://study.com/academy/lesson/island-arc-definition-formation.html
(The whole video won’t play, it’ll get cut-off with a “subscription,” but the
beginning is great!)
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-andRoll 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
Foreshocks and aftershocks
Primary effects of earthquakes: shaking,
permanent vertical or horizontal
displacement of the ground
Richter scale
Insignificant: <4.0
Minor: 4.0–4.9
Damaging: 5.0–5.9
Destructive: 6.0–6.9
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