Plate Tectonics. Brief Structure of the Earth Divided into layers: –Core, mantle, crust.
PLATE TECTONICS: PLATE BOUNDARIES. LAYERS OF THE EARTH 1.Crust (brown/tan) 2.Mantle (light & dark...
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Transcript of PLATE TECTONICS: PLATE BOUNDARIES. LAYERS OF THE EARTH 1.Crust (brown/tan) 2.Mantle (light & dark...
PLATE TECTONICS:PLATE BOUNDARIES
LAYERS OF THE EARTHLAYERS OF THE EARTH
1. Crust (brown/tan)
2. Mantle (light & dark orange)
3. Core (yellow & white)
1. Crust (brown/tan)
2. Mantle (light & dark orange)
3. Core (yellow & white)
LAYERS OF THE EARTHLAYERS OF THE EARTH
Crust and upper mantle make up the LITHOSPHERE
rigid plates (OCEANIC & CONTINENTAL plates)
low temperature & pressure
Crust and upper mantle make up the LITHOSPHERE
rigid plates (OCEANIC & CONTINENTAL plates)
low temperature & pressure
Lithosphere {
Beneath the lithosphere is the ASTHENOSPHERE
plastic” mantle (flows, moves the plates)
higher temperature & pressure
Beneath the lithosphere is the ASTHENOSPHERE
plastic” mantle (flows, moves the plates)
higher temperature & pressure
PLATE TECTONICS PLATE TECTONICSthe surface of the Earth is made of rigid platesthe surface of the Earth is made of rigid plates
Size and position of plates can change over time
PLATE BOUNDARIES Edges of plates, where two plates “float” side-by-side, is where geologic activity takes place
Plates movement is from convection currents deep in the mantle
Size and position of plates can change over time
PLATE BOUNDARIES Edges of plates, where two plates “float” side-by-side, is where geologic activity takes place
Plates movement is from convection currents deep in the mantle
EARTH’S MAJOR PLATES:EARTH’S MAJOR PLATES:Pacific, N. American, S. American, African, Eurasian, Indian, AntarcticPacific, N. American, S. American, African, Eurasian, Indian, Antarctic
CONVECTION CURRENTS MOVE THE PLATES
CONVECTION CURRENTS MOVE THE PLATES
CONVECTION CURRENTS MOVE THE PLATES
CONVECTION CURRENTS MOVE THE PLATES
This continual movement (called convection currents) causes the crust to move in plate tectonics.
CONVECTION CURRENTS MOVE THE PLATES
CONVECTION CURRENTS MOVE THE PLATES
Material in the mantle is heated by the radioactive core
it floats to the surface next to the crust
as it cools, it moves back down towards the core
Material in the mantle is heated by the radioactive core
it floats to the surface next to the crust
as it cools, it moves back down towards the core
7c Movement of matter among reservoirs is driven by Earth’s internal and external sources of energy
PLATE BOUNDARIESPLATE BOUNDARIES
Divergent boundaries plates move apart
Convergent boundaries plates move together
Transform boundaries plates slide past
DIVERGENT BOUNDARIESMake new crust
DIVERGENT BOUNDARIESMake new crust
When two plates move apart and magma surfaces forming NEW crust (usually oceanic)When two plates move apart and magma surfaces forming NEW crust (usually oceanic)
• continental rift zones (landmass splits into two or more segments)
• mid-ocean ridges (sea-floor is elevated)
DIVERGENT BOUNDARIESMake new crust
DIVERGENT BOUNDARIESMake new crust
Rift valley continent-continent
DIVERGENT BOUNDARIESMake new crust: Sea Floor Spreading
Youngest rocks form at ridge
Older rocks are further from ridge
Oldest rocks are located at subduction zones
DIVERGENT BOUNDARIESMake new crust: Sea Floor SpreadingDIVERGENT BOUNDARIESMake new crust: Sea Floor Spreading
As magma rises and cools, iron and magnesium minerals align themselves to the Earth’s magnetic field
“Magnetic Stripes” are formed
The Earth’s magnetic field reverses polarity
Magnetic stripes are mirrored on each side of the mid-ocean ridge
As magma rises and cools, iron and magnesium minerals align themselves to the Earth’s magnetic field
“Magnetic Stripes” are formed
The Earth’s magnetic field reverses polarity
Magnetic stripes are mirrored on each side of the mid-ocean ridge
Every ~20,000 years the polarity of the Earth changes. This is change is reflected in the rocks, whose polarity is fixed once the magma is cooled.
CONVERGENT BOUNDARIESplates colliding
CONVERGENT BOUNDARIESplates colliding
Destroys old crust and forms new mountains
Three types of convergent boundaries
Destroys old crust and forms new mountains
Three types of convergent boundaries
CONVERGENT BOUNDARIESplates colliding
CONVERGENT BOUNDARIESplates colliding
Continent-continent convergence: Folded mountainsContinent-continent convergence: Folded mountains
Ex HimalayasEurasian/Indian plates
CONVERGENT BOUNDARIESplates colliding: Subduction ZonesCONVERGENT BOUNDARIESplates colliding: Subduction Zones
Subduction Zones: where ocean plates slide under another plate
Creates magma which moves upward, pushing up the land above it.
Magma/lava solidifies into intrusive/extrusive igneous rock
Heat from the magma can change the rock around it. Rock that recrystallizes without melting becomes metamorphic rock..
Denser oceanic plates always subduct beneath less dense continental plates
CONVERGENT BOUNDARIESplates colliding
CONVERGENT BOUNDARIESplates colliding
Ocean-continent convergence:
Trench & Coastal Volcanoes
Ocean-continent convergence:
Trench & Coastal Volcanoes
Andes MountainsNazca & S.American plates
CONVERGENT BOUNDARIESplates colliding
CONVERGENT BOUNDARIESplates colliding
Ocean-ocean convergence:
Trench & Island arc
Ocean-ocean convergence:
Trench & Island arc
TRANSFORM BOUNDARIESTRANSFORM BOUNDARIESWhen two plates slide past each otherWhen two plates slide past each other
no tearing or crushing - no damage occurs to the lithosphere
Faults –San Andreas Fault
Cause most earthquake damage
no tearing or crushing - no damage occurs to the lithosphere
Faults –San Andreas Fault
Cause most earthquake damage
Summary of Plate Movements
Convection currents
