Plate
Tectonics

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-Provides the mechanisms for the next segment of class
- Earthquakes
- Volcanoes
- Earth is a dynamic system not only as climate, but in solids as well
- Rock solids move and interact
- Source of energy is from within the Earth
- Residual heat from Earth’s formation
- Very term and concept heavy. Get these things down…

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Components of Earth
Crust (two types)Oceanic Crust- Thin, dense crust formed at mid-ocean ridges
(basaltic).
Continental CrustThick, less dense continental material (silicic).
Mantle- Solid but acts plastic (moves over geologic time)
Outer Core- Liquid iron and nickel
Inner Core- Solid iron and nickel

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Components of Earth
LithosphereConsists of crust and upper part of upper mantle
AsthenosphereConsists of highly viscous portion of the upper mantle

These terms are described by their mechanical qualities, not chemical/mineral!

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- Crust is broken into pieces
- Called Tectonic Plates
- These plates move atop the mantle due to underlying forces (and others).
We call this processPlate Tectonics- The big picture that describes movement of crustal plates.

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Driving forces

Convection drives plate tectonics. Tectonic plates in turn move on atop the currents and interact with each other
- Smashing into each other - Pulling away from each other - Rubbing against each other GSC 350
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Boundaries

3 types
Divergent- Where plates pull apart

Convergent- Where plates smash together

Transform- Where plates pass one another

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Boundaries

Divergent Boundary- Rising magma creates pull apart conditions and crust rips apart. New crust forms at boundary.

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Boundaries

Divergence of rock (think of this as stretching) can occur on a continent. Leads to a thinning of the continent and ‘Basin and Range’ (Nevada)

Nevada is America’s stretch mark

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Boundaries

Convergent
Boundary- Two plates smash into each other.
These are subduction zones and collision zones
(mountain
building areas).

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Boundaries

Hand sample rock densities- Oceanic Crust
(basalt) is