When Plates Collide

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When Plates Collide!
Plate Boundaries

• Divergent
• Convergent
• Strike Slip

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Divergent Boundaries

• -Plates moving apart
• Ex. Mid-Atlantic ridge

Great rift Valley
Fault block Mts.
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Convergent Boundaries

• -Plates are moving together

WHEN PLATES COLLIDE!
Ex. S. America, Andes Mts.
3 Types
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Convergent Boundaries

• 1. 2 Oceanic Plates

Older more dense plate gets subducted
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Convergent Boundaries

• 2. 2 Continental Plates

Large Mt. ranges.

• little to no subduction
• No volcanos

Ex. Himalayans
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Convergent Boundaries

• 3. Oceanic vs. Continental

More dense
less dense
SUBDUCTION ZONE Volcanos
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Transform Boundaries

• -Plates slide past each other

Strike slip OR
In opposite directions
In the same direction But at different rates
Ex. San Andres Fault
EARTHQUAKES!!!
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Causes of Plate Tectonics

• Convection Inside the Earth

Like a Lava Lamp
- Thought to be the force behind the plate
movement
Convection Current- Current in the Earths mantle
that transfers heat in Earths interior
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Convection Currents

• Moving Mantle Material

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Features Caused by Plate Tectonics

• Mountains

Volcanoes
Ocean Basins
Changed Landscapes due to earthquakes Volcanoes.
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Normal Faults and Rift Valleys
Tension Forces

• Divergent Boundary

Forms Fault block Mts. Mid-Ocean Ridges Rift
Valleys
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Mountains Volcanoes

• Compression Forces

Convergent Boundary
Forms Mts. Volcanoes Island Arcs
Folding and Faulting
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Mountains Volcanoes

• Faulting and Folding

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Strike Slip Faults

• Shearing Forces

Transform Boundary
San Andres Fault
Stick / slide
EARTHQUAKES
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Testing for Plate Tectonics

• (Until recently evidence was Indirect)

- Use of satellites and lasers
Plates move from 1-12 cm per year
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Tension
Divergent
Convergent
Compression
Strike/Slip
Shearing