1. Introduction to Earth’s Systems and Earth Science
Plate Tectonics Review
Introduction to Earth’s Systems and Earth Science
Textbook pages

2. Earth and our Solar System
_________ planet from the Sun
3rd
*only planet that can support _______________
life
*orbits the Sun in an ____________ pattern/shape
elliptical
*takes ________ days to complete one orbit
365
*takes _____ hours to complete one rotation 24
*was formed _______ billion years ago
4.6

3. 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

4. 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)

5. 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

6. 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

7. 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 ° C

9. 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

10. 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.

11. 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.

12. Plate tectonics are responsible for Major Features of the Earth’s Crust and Upper Mantle

13. World Plates This diagram shows the major Tectonic Plates.
Presenter: Point out the UK, sitting on the Eurasian Plate. Also the plate boundary between Africa and South America (note that it has the same shape as the coastlines in these countries).

14. 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.
Plates are made of rigid lithosphere – formed of the crust and the extreme upper mantle (point out these layers on the figure).

15. What lies beneath the tectonic plates?
Below the lithosphere (which makes up the tectonic plates) is the asthenosphere.
The asthenosphere, beneath the lithosphere, is part of the upper mantle and is so hot that it is 1 – 5% liquid (I.e. 95 – 99% solid). This liquid, usually at the junctions of the crystals, allow it to flow – which is why ‘astheno’ means weak.’ Beneath the asthenosphere is the rest of the mantle, which is completely solid – but can also flow (on geological time scales) because of the intense temperatures and pressures involved.
The base of the lithosphere-asthenosphere boundary corresponds approximately to the depth of the melting temperature in the mantle.
The plastic layer below the lithosphere
The plates of the lithosphere float on the asthenosphere

16. 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

17. Plate tectonics = movement of lithospheric plates
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)

18. The Earth’s Crust Is Made Up of a Mosaic of Huge Rigid Plates: Tectonic Plates

20. 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

21. 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

22. Creation of a Volcano

23. 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)

24. Island Arc Formation & The “Ring of Fire”
(The whole video won’t play, it’ll get cut-off with a “subscription,” but the beginning is great!)

25. 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.

27. 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
Minor: 4.0–4.9
Damaging: 5.0–5.9
Destructive: 6.0–6.9
Major: 7.0–7.9
Great: >8.0
Foreshocks and aftershocks
Primary effects of earthquakes: shaking, permanent vertical or horizontal displacement of the ground

28. Major Features and Effects of an Earthquake

29. Areas of Greatest Earthquake Risk in the United States

30. Areas of Greatest Earthquake Risk in the World

31. 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