Processes of Lithosphere
Lithosphere
• Rigid outermost shell of a rocky planet
– On earth, comprises the crust and the upper
mantle
The Rock Cycle
Thinking about relationships among
the major rock groups
Major Rock Groups
• Igneous
– Formed from a melt (molten rock)
– Plutonic (intrusive):slow cooling and crystallization
– Volcanic (extrusion): quick cooling at the surface
• Sedimentary
– Formed at the Earth’s surface
• Metamorphic
– Changed by pressure, temperature and fluids.
5
Fig. 2.9
MAGMA
IGNEOUS
Crystallization
MAGMA
7
IGNEOUS
Plutonic
Crystallization
MAGMA
8
Volcanic
IGNEOUS
Plutonic
Crystallization
MAGMA
9
Weathering
Volcanic
IGNEOUS
Plutonic
Crystallization
Uplift
MAGMA
10
Weathering
• Chemical – changing composition
(acid rain)
• Physical – Breaking apart rocks,
moving soils, etc
• Soil is result of weathering of rocks
and includes weathered particles
Weathering
SEDIMENT
Volcanic
IGNEOUS
Plutonic
Crystallization
Uplift
MAGMA
12
Weathering
SEDIMENT
Erosion
Transport
Deposition
Volcanic
IGNEOUS
SEDIMENTARY
Plutonic
Crystallization
Uplift
MAGMA
13
Weathering
SEDIMENT
Erosion
Transport
Deposition
Volcanic
IGNEOUS
SEDIMENTARY
Plutonic
Crystallization
Uplift
MAGMA
14
Weathering
SEDIMENT
Erosion
Transport
Deposition
Volcanic
IGNEOUS
SEDIMENTARY
Plutonic
Increased P&T
METAMORPHIC
Crystallization
Burial
Uplift
MAGMA
15
SEDIMENT
Weathering
Erosion
Transport
Volcanic
Can you see
IGNEOUS
any shortcuts?
Deposition
SEDIMENTARY
Plutonic
Increased P&T
METAMORPHIC
Crystallization
Melting
Uplift
Burial
MAGMA
16
Weathering
SEDIMENT
Erosion
Transport
Deposition
Volcanic
IGNEOUS
SEDIMENTARY
Plutonic
Increased P&T
METAMORPHIC
Crystallization
Melting
Uplift
Burial
MAGMA
17
In Conclusion…
• The rock cycle
demonstrates the
relationships among the
three major rock groups
• It is powered by the
interior heat of the Earth
• The energy from the sun
• It involves processes on
the Earth’s surface as
well as the Earth’s
interior.
The Structure of the Earth and Plate
Tectonics
Structure of the Earth
• The Earth is made
up of 3 main
layers:
– Core
– Mantle
– Crust
Crust
Mantle
Outer core
Inner core
The Crust
• This is where we live!
• The Earth’s crust is made of:
Continental Crust
- buoyant (less dense
than oceanic crust)
Oceanic Crust
- dense (sinks under
continental crust)
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.
Plate 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.
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.
Plate Movement
• “Plates” of lithosphere are moved around by the
underlying hot mantle convection cells
Three types of plate boundary
• Divergent
• Convergent
• Transform
Divergent Boundaries
• Spreading ridges
– As plates move apart new material is erupted to fill
the gap
Iceland: An example of continental rifting
• Iceland has a divergent plate
boundary running through its
middle
Convergent Boundaries
• There are three styles of convergent plate
boundaries
– Continent-continent collision
– Continent-oceanic crust collision
– Ocean-ocean collision
Continent-Continent Collision
• Forms mountains, e.g. European Alps, Himalayas
Himalayas
Continent-Oceanic Crust Collision
• Called SUBDUCTION
• Area is called the subduction zone
Transform Boundaries
• Where plates slide past each other
Above: View of the San Andreas
transform fault
Volcanoes and Plate Tectonics…
…what’s the connection?
Pacific Ring of Fire
Volcanism is
mostly focused at
plate margins
Volcanoes are formed by:
- Subduction - Rifting - Hotspots
Subduction
• Form new melt that will rise through the crust
to be erupted at the surface
Rifting
• Form new melt that will rise through the crust
to be erupted at the surface
Hot Spots
• Does not occur along a plate boundary.
• Form in the middle of tectonic plates
Volcanic Eruptions
• Pyroclastic Flow – cloud of ash and debris
– Travel at hundreds of mph
– Hundreds of degrees
Volcanic Eruptions
• Lahar – mud flows which are very destructive to
landscape
Volcanic Eruptions
•
•
•
•
•
“Ash” emitted includes small stones
Very dense
Chokes life
Blots out sunlight
Causes wide range temperature drops
http://www.youtube.c
om/watch?v=UK-hvgP2uY
Earthquakes and Plate Tectonics…
…what’s the connection?
• As with volcanoes, earthquakes are not
randomly distributed over the globe
Figure showing the
distribution of
earthquakes
around the globe
• At the boundaries between plates, friction
causes them to stick together. When built up
energy causes them to break, earthquakes occur.
Where do earthquakes form?
Figure showing the tectonic setting of earthquakes
Fault Lines
• Strike – slip
• Reverse
• Normal
Earthquake Anatomy
• Focal point – where the actual earth quake
originated underground
• Epicenter – location of earth quake on earth’s
surface
– Above the focal point
Earthquake Anatomy
• P Waves (primary) – waves which travel
fastest, first, and moves through any material
– Reach seismographs
– Moves land back and forth
• S Waves (secondary) – actual surface waves
which travel slower and only moves through
solids
– Moves land up and down
http://www.teara.govt.nz/en/interactive/4403
/primary-and-secondary-waves
Results..
•
•
•
•
Land destruction/alteration
Fire (breaking of gas and power lines)
Buildings destroyed
Tsunami’s
Tsunami
• “Harbor Wave”