CRUST
• THICKNESS: VARIES BETWEEN OCEAN & CONTINENTS 5-40 KM
• STATE: SOLID
• ELEMENTS: SILICON, ALUMINUM, CALCIUM, SODIUM, POTASSIUM
• LOCATION OF THE EARTH’S “PLATES”
• FLOATS ON THE LAYER BENEATH
• LEAST DENSE LAYER
• CONTINENTAL AND OCEANIC CRUSTS
• LITHOSPHERE= CRUSTS + UPPER MOST PART OF MANTLE
Layers of the Earth
MANTLE
• THICKNESS: 2,750 KM
• STATE: PLASTIC- ABILITY OF A SOLID TO FLOW
• ELEMENTS: SILICON, OXYGEN, MAGNESIUM, IRON, ALUMINUM, CALCIUM
• CONVECTION CURRENTS
• DUE TO UNEVEN HEATING IN THIS LAYER
• CAUSE THE EARTH’S PLATES TO MOVE
• ASTHENOSPHERE AND MESOSPHERE
Layers of the Earth
OUTER CORE
• THICKNESS: 2,260 KM
• STATE: LIQUID
• ELEMENTS: IRON AND NICKEL
• EXTREMELY HOT
• RESPONSIBLE FOR OUR MAGNETIC FIELD
Layers of the Earth
INNER CORE
• THICKNESS: 1,228 KM
• STATE: SOLID
• TEMPERATURE AND PRESSURE IS SO GREAT, THAT THE METALS ARE
SQUEEZED TOGETHER AND CANNOT MOVE.
• ELEMENTS: IRON AND NICKEL
Layers of the Earth
PLATE TECTONICS
• ALFRED WEGENER
• KNOWN FOR HIS THEORY ON
CONTINENTAL DRIFT
• 1915- PUBLISHED THE ORIGINS OF
CONTINENTS AND OCEANS
• CONTINENTAL DRIFT
• SUPERCONTINENT- PANGEA
Plate Tectonics
PLATE TECTONICS
• CONTINENTAL DRIFT SUPPORTED BY:
• IDENTICAL FOSSILS FOUND ON DIFFERENT CONTINENTS
• CONTINENTS “FIT” TOGETHER LIKE PUZZLE PIECES
• GEOLOGICAL FEATURES MATCH TOGETHER
• COAL DEPOSITS IN EUROPE AND N. AMERICA
• MOUNTAIN RANGES IN AFRICA AND S. AMERICA
Plate Tectonics
PLATE TECTONICS
• SO WHAT CAUSED THE PLATES
TO MOVE APART?
• THE CRUST IS MADE UP OF
SEVERAL DIFFERENT PLATES THAT
CAN MOVE INDEPENDENTLY OF
ONE ANOTHER
• CONVECTION CURRENTS IN THE
MANTLE PUSH/PULL THE PLATES
Plate Tectonics
DIVERGENT BOUNDARIES
• OCEAN- (SEA-FLOOR SPREADING)
• TWO PLATES MOVE AWAY FROM EACH OTHER
• MAGMA MOVES UP TO FILL THE SPACE
CREATING NEW ROCK
• FORMS OCEAN RIDGES
• CONTINENTAL-
• FORMS RIFT VALLEYS
Plate Tectonics
CONVERGENT BOUNDARIES
• PLATES MOVE TOWARDS EACH OTHER
• AKA: SUBDUCTION ZONES- AREAS OF
PLATE DESTRUCTION
• 3 TYPES:
• OCEANIC- OCEANIC
• OCEANIC- CONTINENTAL
• CONTINENTAL- CONTINENTAL
Plate Tectonics
CONVERGENT: OCEANIC- OCEANIC
• FORMS:
• TRENCHES
• ISLAND ARCS
Plate Tectonics
CONVERGENT: CONTINENTAL- CONTINENTAL
• FORMS:
• MOUNTAINS
Plate Tectonics
TRANSFORM BOUNDARIES
• OCCURS AS TWO PLATES SLIDE
PAST EACH OTHER
• NO PLATE DESTRUCTION
• EARTHQUAKES ARE COMMON
DUE TO FRICTION
• OFFSETS GEOLOGIC FEATURES
Plate Tectonics
OTHER CIRCUMSTANCES
• SOME AREAS HAVE PLUMES OF
MAGMA CLOSE TO THE SURFACE
• AKA: HOT-SPOTS
• RESPONSIBLE FOR SEVERAL ISLAND
CHAINS INCLUDING HAWAII
• MAGMA RISES TO THE SURFACE AT
VOLCANOES CREATING NEW
ISLANDS
Plate Tectonics