the structure of the earth and plate tectonics by: ms. nikki
TRANSCRIPT
The Structure of the Earth and Plate Tectonics
The Structure of the Earth and Plate Tectonics
By: Ms. Nikki
Journey to the Center of the
Earth
Journey to the Center of the
EarthWhat would I
find if I journeyed to the center of
the Earth?
What would I find if I
journeyed to the center of
the Earth?
How did the layers form?How did the layers form?
How did the layers form?How did the layers form?
•The Earth’s layers were formed because of density.
•The Earth’s layers were formed because of density.
How did the layers form?How did the layers form?
•The Earth’s layers were formed because of density.–The heavier, more dense, materials were pulled in more by gravity.
•The Earth’s layers were formed because of density.–The heavier, more dense, materials were pulled in more by gravity.
How did the layers form?How did the layers form?
•The Earth’s layers were formed because of density.– The heavier, more dense,
materials were pulled in more by gravity.
– Lighter, less dense, materials were not pulled in as much by gravity.
•The Earth’s layers were formed because of density.– The heavier, more dense,
materials were pulled in more by gravity.
– Lighter, less dense, materials were not pulled in as much by gravity.
What are the layers made of?
What are the layers made of?
What are the layers made of?
What are the layers made of?
•Inner Core: solid iron (Fe) and Nickel (Ni).
•Inner Core: solid iron (Fe) and Nickel (Ni).
What are the layers made of?
What are the layers made of?
•Inner Core: solid iron (Fe) and Nickel (Ni).– Pressure is 48 to 52 million
psi.
•Inner Core: solid iron (Fe) and Nickel (Ni).– Pressure is 48 to 52 million
psi.
What are the layers made of?
What are the layers made of?
•Inner Core: solid iron (Fe) and Nickel (Ni).– Pressure is 48 to 52 million
psi.– Temperatures range from
about 9,000 to 12,000 degrees Fahrenheit.
•Inner Core: solid iron (Fe) and Nickel (Ni).– Pressure is 48 to 52 million
psi.– Temperatures range from
about 9,000 to 12,000 degrees Fahrenheit.
What are the layers made of?
What are the layers made of?
•Outer core: liquid iron (Fe) and Nickel (Ni).
•Outer core: liquid iron (Fe) and Nickel (Ni).
What are the layers made of?
What are the layers made of?
•Outer core: liquid iron (Fe) and Nickel (Ni).– Temperatures range from
about 4,400 to 6,100 degrees Fahrenheit.
•Outer core: liquid iron (Fe) and Nickel (Ni).– Temperatures range from
about 4,400 to 6,100 degrees Fahrenheit.
What are the layers made of?
What are the layers made of?
•Outer core: liquid iron (Fe) and Nickel (Ni).– Temperatures range from
about 4,400 to 6,100 degrees Fahrenheit.
– It is believed that the Earth’s magnetism is produced here.
•Outer core: liquid iron (Fe) and Nickel (Ni).– Temperatures range from
about 4,400 to 6,100 degrees Fahrenheit.
– It is believed that the Earth’s magnetism is produced here.
What are the layers made of?
What are the layers made of?
•Mantle: •Mantle:
What are the layers made of?
What are the layers made of?
•Mantle: – Made of various minerals
(Iron (Fe), Magnesium (Mg), Aluminum (Al), Silicon (Si), and Oxygen silicates ) that are in constant motion.
•Mantle: – Made of various minerals
(Iron (Fe), Magnesium (Mg), Aluminum (Al), Silicon (Si), and Oxygen silicates ) that are in constant motion.
What are the layers made of?
What are the layers made of?
•Mantle: – Made of various minerals
(Iron (Fe), Magnesium (Mg), Aluminum (Al), Silicon (Si), and Oxygen silicates ) that are in constant motion.
– Temperatures of up to 6,700 degrees Fahrenheit.
•Mantle: – Made of various minerals
(Iron (Fe), Magnesium (Mg), Aluminum (Al), Silicon (Si), and Oxygen silicates ) that are in constant motion.
– Temperatures of up to 6,700 degrees Fahrenheit.
What are the layers made of?
What are the layers made of?
•Crust:•Crust:
What are the layers made of?
What are the layers made of?
•Crust: The top layer of the Earth
•Crust: The top layer of the Earth
What are the layers made of?
What are the layers made of?
•Crust: The top layer of the Earth– The two types are
continental and oceanic.
•Crust: The top layer of the Earth– The two types are
continental and oceanic.
What are the layers made of?
What are the layers made of?
•Crust: The top layer of the Earth– The two types are
continental and oceanic.– Made of mostly Silicon (Si),
Aluminum (Al), Calcium (Ca), Sodium (Na), and Potassium (K)
•Crust: The top layer of the Earth– The two types are
continental and oceanic.– Made of mostly Silicon (Si),
Aluminum (Al), Calcium (Ca), Sodium (Na), and Potassium (K)
What are the layers made of?
What are the layers made of?
•Crust: The top layer of the Earth– The two types are continental
and oceanic.– Made of mostly Silicon (Si),
Aluminum (Al), Calcium (Ca), Sodium (Na), and Potassium (K)
– Fractures during earthquakes.
•Crust: The top layer of the Earth– The two types are continental
and oceanic.– Made of mostly Silicon (Si),
Aluminum (Al), Calcium (Ca), Sodium (Na), and Potassium (K)
– Fractures during earthquakes.
Where is the lithosphere?Where is the lithosphere?
Where is the lithosphere?Where is the lithosphere?
•The lithosphere contains:
•The lithosphere contains:
Where is the lithosphere?Where is the lithosphere?
•The lithosphere contains:–The crust.
•The lithosphere contains:–The crust.
Where is the lithosphere?Where is the lithosphere?
•The lithosphere contains:–The crust.–A small layer of the upper mantle.
•The lithosphere contains:–The crust.–A small layer of the upper mantle.
Where is the lithosphere?Where is the lithosphere?
•The lithosphere contains:– The crust.– A small layer of the upper
mantle.• Large chunks or plates that
move gradually because they ride on hotter parts of the mantle.
•The lithosphere contains:– The crust.– A small layer of the upper
mantle.• Large chunks or plates that
move gradually because they ride on hotter parts of the mantle.
Where is the lithosphere?Where is the lithosphere?
• The lithosphere contains:– The crust.– A small layer of the upper
mantle.• Large chunks or plates that move
gradually because they ride on hotter parts of the mantle.– These “chunks” or plates make
up the surface of the Earth.
• The lithosphere contains:– The crust.– A small layer of the upper
mantle.• Large chunks or plates that move
gradually because they ride on hotter parts of the mantle.– These “chunks” or plates make
up the surface of the Earth.
Structure of the EarthStructure of the Earth
• The Earth is made up of 3 main layers:– Core– Mantle– Crust
• The Earth is made up of 3 main layers:– Core– Mantle– Crust
Inner core
Outer core
Mantle
Crust
What IS the Lithosphere?What IS the Lithosphere?
• The lithosphere is made up of the crust and small layer of the upper mantle that together form large chunks or plates that move gradually because they ride on hotter mantle. These plates make up the surface of the Earth.
• The lithosphere is made up of the crust and small layer of the upper mantle that together form large chunks or plates that move gradually because they ride on hotter mantle. These plates make up the surface of the Earth.
Warm UpWarm Up
• 1. Take out a piece of paper and put your name on it.
• 2. BE QUIET!
• 1. Take out a piece of paper and put your name on it.
• 2. BE QUIET!
The CrustThe Crust• This is where we live!
• The Earth’s crust is made of:
• This is where we live!
• The Earth’s crust is made of:
Continental Crust
- thick (10-70km)- buoyant (less dense than oceanic crust) - mostly old
Oceanic Crust
- thin (~7 km)- dense (sinks under continental crust)- young
How do we know what the Earth is made of?
How do we know what the Earth is made of?
• Geophysical surveys: seismic, gravity, magnetic, electrical, geodesy– Acquisition: land, air, sea and satellite
– Geological surveys: fieldwork, boreholes, mines
• Geophysical surveys: seismic, gravity, magnetic, electrical, geodesy– Acquisition: land, air, sea and satellite
– Geological surveys: fieldwork, boreholes, mines
• http://video.google.com/videoplay?docid=4835712194315869074#
• http://video.google.com/videoplay?docid=4835712194315869074#
What are Plate Tectonics?What are 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.
• 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.
Plate TectonicsPlate Tectonics
• The Earth’s crust is divided into 12 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.
• The Earth’s crust is divided into 12 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.
World PlatesWorld Plates
What are tectonic plates made of?
What are tectonic plates made of?
• Plates are made of rigid lithosphere.
• 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?
What lies beneath the tectonic plates?
• Below the lithosphere (which makes up the tectonic plates) is the asthenosphere.
• Below the lithosphere (which makes up the tectonic plates) is the asthenosphere.
Continents of the PastContinents of the Past• “Pangaea” : exists ~ 225 million years
ago– Supercontinent: the only continent on Earth
• Division of Pangaea ~ 135 million years ago– Into “Laurasia” (N. Hem)
• Included modern North America & Eurasia
– And “Gondwana” (S. Hem)• Included modern South America, Africa,
Antarctica, Australia, Madagascar, India and New Zealand
• “Pangaea” : exists ~ 225 million years ago– Supercontinent: the only continent on Earth
• Division of Pangaea ~ 135 million years ago– Into “Laurasia” (N. Hem)
• Included modern North America & Eurasia
– And “Gondwana” (S. Hem)• Included modern South America, Africa,
Antarctica, Australia, Madagascar, India and New Zealand
250 Million Years Ago250 Million Years Ago
200 Million Years Ago200 Million Years Ago
135 Million Years AgoJurassic Period
135 Million Years AgoJurassic Period
65 Million Years Ago65 Million Years Ago
Present DayPresent Day
In 250 Million YearsIn 250 Million Years
What is a convection current?
What is a convection current?
• A convection current is a circular flow due to molecules heating, moving faster, and becoming less dense-so they weigh less and rise.
• When they cool, they move slower and closer together-so they weigh more per space and sink.
• A convection current is a circular flow due to molecules heating, moving faster, and becoming less dense-so they weigh less and rise.
• When they cool, they move slower and closer together-so they weigh more per space and sink.
Plate MovementPlate Movement
• “Plates” of lithosphere are moved around by the underlying hot mantle convection cells
• “Plates” of lithosphere are moved around by the underlying hot mantle convection cells
e
Warm UpWarm Up
• 1. What is the lithosphere?• 2. List the EM spectrum in order
from lowest frequency to highest.• 3. How do we hear?• 4. What is refraction?• 5. How do plates move?
• 1. What is the lithosphere?• 2. List the EM spectrum in order
from lowest frequency to highest.• 3. How do we hear?• 4. What is refraction?• 5. How do plates move?
What happens at tectonic plate boundaries?
What happens at tectonic plate boundaries?
• Divergent
• Convergent
• Transform
• Divergent
• Convergent
• Transform
Three types of plate boundary
• Spreading ridges– As plates move apart new material is
erupted to fill the gap
• Spreading ridges– As plates move apart new material is
erupted to fill the gap
Divergent Boundaries
What happens when plates move toward each other?
What happens when plates move toward each other?
• This is called a Convergent boundary– The continental plates push up and
make mountains OR….
• This is called a Convergent boundary– The continental plates push up and
make mountains OR….
DRAW
Plate BoundariesPlate Boundaries
• It’s called Subduction– When one plate dives under the
other.
• It’s called Subduction– When one plate dives under the
other.
SubductionSubduction
Plate BoundariesPlate Boundaries
• Transform boundary– Happens when 2 plates beside each
other move in opposite directions
• Transform boundary– Happens when 2 plates beside each
other move in opposite directions
• http://science.discovery.com/tv-shows/greatest-discoveries/videos/100-greatest-discoveries-plate-tectonics.htm
• http://www.youtube.com/watch?v=KCSJNBMOjJs&safe=active (15 mins)
• http://science.discovery.com/tv-shows/greatest-discoveries/videos/100-greatest-discoveries-plate-tectonics.htm
• http://www.youtube.com/watch?v=KCSJNBMOjJs&safe=active (15 mins)
Age of Oceanic Crust
Courtesy of www.ngdc.noaa.gov
• Iceland has a divergent plate boundary running through its middle
• Iceland has a divergent plate boundary running through its middle
Iceland: An example of continental rifting
• There are three styles of convergent plate boundaries– Continent-continent collision– Continent-oceanic crust collision– Ocean-ocean collision
• There are three styles of convergent plate boundaries– Continent-continent collision– Continent-oceanic crust collision– Ocean-ocean collision
Convergent Boundaries
• Forms mountains, e.g. European Alps, Himalayas
• Forms mountains, e.g. European Alps, Himalayas
Continent-Continent Collision
Himalayas
• Called SUBDUCTION• Called SUBDUCTION
Continent-Oceanic Crust Collision
• Oceanic lithosphere subducts underneath the continental lithosphere
• Oceanic lithosphere heats and dehydrates as it subsides
• The melt rises forming volcanism
• E.g. The Andes
• Oceanic lithosphere subducts underneath the continental lithosphere
• Oceanic lithosphere heats and dehydrates as it subsides
• The melt rises forming volcanism
• E.g. The Andes
Subduction
• When two oceanic plates collide, one runs over the other which causes it to sink into the mantle forming a subduction zone.
• The subducting plate is bent downward to form a very deep depression in the ocean floor called a trench.
• The worlds deepest parts of the ocean are found along trenches. – E.g. The Mariana Trench is 11 km(6.8 miles)
deep!
• When two oceanic plates collide, one runs over the other which causes it to sink into the mantle forming a subduction zone.
• The subducting plate is bent downward to form a very deep depression in the ocean floor called a trench.
• The worlds deepest parts of the ocean are found along trenches. – E.g. The Mariana Trench is 11 km(6.8 miles)
deep!
Ocean-Ocean Plate Collision
• Where plates slide past each other• Where plates slide past each other
Transform Boundaries
Above: View of the San Andreas transform fault
Plate Tectonics SummaryPlate Tectonics Summary• The Earth is made up of 3 main layers
(core, mantle, crust)• On the surface of the Earth are tectonic
plates that slowly move around the globe• Plates are made of crust and upper mantle
(lithosphere)• There are 2 types of plate• There are 3 types of plate boundaries• Volcanoes and Earthquakes are closely
linked to the margins of the tectonic plates
• The Earth is made up of 3 main layers (core, mantle, crust)
• On the surface of the Earth are tectonic plates that slowly move around the globe
• Plates are made of crust and upper mantle (lithosphere)
• There are 2 types of plate• There are 3 types of plate boundaries• Volcanoes and Earthquakes are closely
linked to the margins of the tectonic plates