processes of lithosphere
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Processes of Lithosphere
Lithosphere
• Rigid outermost shell of a rocky planet– On earth, comprises the crust and the upper
mantle
The Rock CycleThinking about relationships among
the major rock groups
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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.
Fig. 2.9
MAGMA
7
MAGMA
Crystallization
IGNEOUS
8
MAGMA
IGNEOUS
Plutonic
Crystallization
9
MAGMA
Volcanic
IGNEOUS
Plutonic
Crystallization
10
MAGMA
Volcanic
IGNEOUS
Plutonic
Uplift
Crystallization
Weathering
Weathering• Chemical – changing composition
(acid rain)
• Physical – Breaking apart rocks, moving soils, etc
• Soil is result of weathering of rocks and includes weathered particles
12
MAGMA
Volcanic
IGNEOUS
Plutonic
SEDIMENT
Uplift
Crystallization
Weathering SEDIMENT
13
MAGMA
Volcanic
IGNEOUS
Plutonic
SEDIMENT
SEDIMENTARY
Uplift
Crystallization
Weathering Erosion
Transport
Deposition
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MAGMA
Volcanic
IGNEOUS
Plutonic
SEDIMENT
SEDIMENTARY
Uplift
Crystallization
Weathering Erosion
Transport
Deposition
15
MAGMA
Volcanic
IGNEOUS
Plutonic
SEDIMENT
SEDIMENTARY
METAMORPHIC
UpliftBurial
Increased P&T
Crystallization
Weathering Erosion
Transport
Deposition
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MAGMA
Volcanic
IGNEOUS
Plutonic
SEDIMENT
SEDIMENTARY
METAMORPHIC
UpliftBurial
Increased P&T
MeltingCrystallization
Weathering Erosion
Transport
DepositionCan you see
any shortcuts?
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MAGMA
Volcanic
IGNEOUS
Plutonic
SEDIMENT
SEDIMENTARY
METAMORPHIC
UpliftBurial
Increased P&T
MeltingCrystallization
Weathering Erosion
Transport
Deposition
• 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.
In Conclusion…
The Structure of the Earth and Plate Tectonics
Structure of the Earth
• The Earth is made up of 3 main layers:– Core– Mantle– Crust
Inner core
Outer core
Mantle
Crust
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
• Divergent
• Convergent
• Transform
Three types of plate boundary
• Spreading ridges– As plates move apart new material is erupted
to fill the gap
Divergent Boundaries
• 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
Convergent Boundaries
• Forms mountains, e.g. European Alps, Himalayas
Continent-Continent Collision
Himalayas
• Called SUBDUCTION• Area is called the subduction zone
Continent-Oceanic Crust Collision
• Where plates slide past each other
Transform Boundaries
Above: View of the San Andreas transform fault
…what’s the connection?
Volcanoes and Plate Tectonics…
Volcanism is mostly focused at plate margins
Pacific Ring of Fire
- Subduction - Rifting - Hotspots
Volcanoes are formed by:
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.com/watch?v=UK--hvgP2uY
…what’s the connection?
Earthquakes and Plate Tectonics…
• As with volcanoes, earthquakes are not randomly distributed over the globe
• At the boundaries between plates, friction causes them to stick together. When built up energy causes them to break, earthquakes occur.
Figure showing the distribution of earthquakes around the globe
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 downhttp://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”
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