lithospheric plate boundaries plate tectonics part 2
DESCRIPTION
Type of Boundary DescriptionSpecial FeatureExample DIVERGENT2 plates separate from each other Move in opposite drx Rift valley Mid Ocean Ridge Sea floor spreading Mid Atlantic Ridge Iceland Red Sea Gulf of Aden CONVERGENT TRANSFORM HOT SPOTTRANSCRIPT
Lithospheric Plate Boundaries
Plate Tectonics Part 2
Type of Boundary
Description Special Feature Example
DIVERGENT
CONVERGENT
TRANSFORM
HOT SPOT
Type of Boundary
Description Special Feature Example
DIVERGENT 2 plates separate from each other
Move in opposite drx
Rift valley
Mid Ocean Ridge
Sea floor spreading
Mid Atlantic RidgeIcelandRed SeaGulf of Aden
CONVERGENT
TRANSFORM
HOT SPOT
Type of Boundary
Description Special Feature Example
DIVERGENT 2 plates separate from each other
Move in opposite drx
Rift valley
Mid Ocean Ridge
Sea floor spreading
Mid Atlantic RidgeIcelandRed SeaGulf of Aden
CONVERGENT 2 plates move toward each other
collide
Subduction zoneMountain chainVolcanoes/EQDeep sea trenches
Mt. St. HelensAndes Mtns.Japan/PhilippinesMarianas Trench
TRANSFORM
HOT SPOT
Type of Boundary
Description Special Feature Example
DIVERGENT 2 plates separate from each other
Move in opposite drx
Rift valley
Mid Ocean Ridge
Sea floor spreading
Mid Atlantic RidgeIcelandRed SeaGulf of Aden
CONVERGENT 2 plates move toward each other
collide
Subduction zoneMountain chainVolcanoes/EQDeep sea trenches
Mt. St. HelensAndes Mtns.Japan/PhilippinesMarianas Trench
TRANSFORM Plates slide past each other
Stressearthquakes
San Andreas Fault
HOT SPOT
Type of Boundary
Description Special Feature Example
DIVERGENT 2 plates separate from each other
Move in opposite drx
Rift valley
Mid Ocean Ridge
Sea floor spreading
Mid Atlantic RidgeIcelandRed SeaGulf of Aden
CONVERGENT 2 plates move toward each other
collide
Subduction zoneMountain chainVolcanoes/EQDeep sea trenches
Mt. St. HelensAndes Mtns.Japan/PhilippinesMarianas Trench
TRANSFORM Plates slide past each other
Stressearthquakes
San Andreas Fault
HOT SPOT Magma rises and punches through the middle of a plate
Island chains form as the plate moves ORGeysers erupt
HawaiiYellowstone NP
WHAT CAUSES TECTONIC ACTIVITY ?1. CONVECTION –
internal heat of the Earth rises
2. RADIOACTIVE DECAY – of Uranium (Ur), Thorium (Th) or Potassium (K)
3. VULCANISM4. CONDUCTIONOther planets have no tectonic
activity because they have already cooled
Movements of Plates
Make a pattern of colored stripes with markers
TYPES OF PLATE BOUNDARIES
• Divergent Margins
• Convergent Margins
• Transform Margins
• Hot Spots
DIVERGENT BOUNDARIES
• Places where 2 (or more) plates are moving apart
• Most found on ocean floor
• As plates separate, narrow “rift” valley forms
• Ex.- Mid Atlantic Ridge, Red Sea, p 249
CONVERGENT BOUNDARIES
• Place where 2 (or more) plates move toward each other, collide
• Types 1 Oceanic-Continental crusts 2 Continental-Continental Crusts 3 Oceanic- Oceanic Crust
1. Oceanic-Continental Crust
• Oceanic crust is more dense (basalt)• It is forced under the continental crust (granite)• Forms deep ocean trench, volcanic
mountains• Ex.- Peru Trench, Andes Mountains, Cascade Mtns
2. Continental-Continental Crust
• Since both plates are of equal density, neither goes under (gets subducted)
• Plates crumple
• Form uplifted mountains• Ex.- Himalayan Mtns.
3. Oceanic-Oceanic Crust
• Bigger plate forces other under• Deep ocean trenches form and volcanic
island arcs
• Ex.- Marianas Trench, Aleutian Islands
TRANSFORM BOUNDARIES
• 2 or more plates slide past each other
• Plates do not slide smoothly-earthquakes
• Scrape and move in spurts
• Ex.- San Andreas Fault
HOT SPOTS
• Small, long lasting, extremely hot area in the middle of a plate
• Provides local source of energy for volcanism
• Plate continues to move, creating new island or feature above hot spot, geysers
• Ex.- Hawaii, Emperor Sea Mounts, Yellowstone N.P.
Geysers
Illustration of Main Boundaries
Why do plate move?
• Convection Currents
Natural Hazards
• Earthquakes
• Volcanoes
• Tsunamis
Natural Resources
• Fertile Soil
• Ore Deposits
• Fossil Fuels
• Geothermal Energy