Transcript Plate Tectonics [ LPI USRA PPT ]

http://www.geophysics.rice.edu/plateboundary/
Where are the Earth’s tectonic plates and
their boundaries?
What happens at plate boundaries?
How do Earth scientists classify plate
boundaries?
Discovering Plate Boundaries
Classification
Discovery based
Emphasizes observation
Data rich
Cooperative learning
Geography
Random group interaction
Writing descriptions
Presentation skills
Map reading
Earth Observation Activity - 1
4 teams: Volcanologists, Seismologists,
Geochronologists, Geographers
What does your map show?
What patterns do you observe on your maps at
/ near plate boundaries? (symmetric, broad,
diffuse, shallow, active, narrow, curved, ridge)
-10 points for each INTERPRETATION!
Classify the boundaries (5 or fewer)
1 map/person!
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Boundary types are to be called Type 1, Type 2, and etc.
Write a description of each boundary type
Assign a color to each boundary type and color it
If the boundary is not symmetric, invent a way to show it
Earth Observation Activity - 2
7 Plate teams (one specialist per): North
American, South American, Indian, Pacific,
African, Australian, Antarctic
Each specialist - share what you know
As a team, classify your PLATE boundaries
• No more than 5; each includes all data types
• Type A, B, C, D ….
• Describe / Color
2-3 minute presentation / plate tomorrow
Earth Observation Activity
2-3 minute overview!
Describe the plate
boundaries
Characteristics and
location?
Comparison to other
groups?
Plate Tectonics
• The upper mechanical layer of Earth (lithosphere) is divided into
rigid plates that move away, toward, and along each other
• Most (!) geologic “action” occurs at plate boundaries
• DISTINCT PATTERNS
Relative Movements of Plates
2 Types of Crust – Oceanic and Continental
Divergent Plate Boundary – Plates pull apart
New ocean crust being made
Divergent Plate Boundary – Plates Pull Apart
Mountain chain / ridge (underwater!) at boundary
Volcanos / fissures (dataset shows only rare volcanos)
Shallow earthquakes
Regular pattern of crust age – young at boundary,
symmetrical around boundary – older away
Volcanic rock types?
Divergent Plate Boundary – Plates Pull Apart
Mountain chain / ridge (underwater!) at boundary
Volcanos / fissures (dataset shows only rare volcanos)
Shallow earthquakes
Regular pattern of crust age – young at boundary,
symmetrical around boundary – older away
Volcanic rock types?
Convergent Plate Boundary – Plates come together
Lithosphere being consumed
3 types
Convergent Plate Boundary – Type 1
Ocean-Continental Crust
Volcanic mountain chain and trench
Volcanos are in a tight line, parallel to boundary
Shallow to deep earthquakes
Irregular pattern of crust age
Volcanic rock types?
Andes Mountains
Nazca Plate
South American Plate
Antarctic Plate
Convergent Plate Boundary – Type 1
Ocean-Continental Crust
Volcanic mountain chain and trench
Volcanos are in a tight line, parallel to boundary
Shallow to deep earthquakes
Irregular pattern of crust age
Volcanic rock types?
Convergent Plate Boundary – Type 2
Ocean-Ocean Crust
Volcanic ISLAND chain and trench … rock types?
Arcuate shape, tightly spaced volcanos
Shallow to deep earthquakes
Irregular pattern of crust age
Convergent Plate Boundary – Type 2
Ocean-Ocean Crust
Volcanic ISLAND chain and trench … rock types?
Arcuate shape, tightly spaced volcanos
Shallow to deep earthquakes
Irregular pattern of crust age
Convergent Plate
Boundary – Type 3
ContinentContinent
MOUNTAINS!
Little volcanic
activity
Shallow to
intermediate
earthquakes
No ocean crust
Tibetan Plateau
Himalayan Mtns.
Mt. Everest
Eurasian Plate
Indian Plate
Himalaya Mountains
Convergent Plate
Boundary – Type 3
ContinentContinent
MOUNTAINS!
Little volcanic
activity
Shallow to
intermediate
earthquakes
No ocean crust
Transform
• Complex topography
• Shallow earthquakes in
broad band
• Broad volcanic bands
• Irregular age patterns
What’s Driving Plate Tectonics
on Earth?
It’s all about convection and heat (loss)!
Vigorous convection drives plate tectonics
Where Does the Heat Come From?
Plate Tectonics
• The upper mechanical layer of Earth (lithosphere) is divided into
rigid plates that move away, toward, and along each other
• Most (!) geologic “action” occurs at plate boundaries
• DISTINCT PATTERNS
Evidence of Heat Loss
Or Plate Tectonics
On Other Planets?