EXAM 2 STUDY GUIDE

EXAM 2 STUDY GUIDE - CHAPTER 3: PLATE TECTONICS CONTINENTAL...

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Unformatted text preview: CHAPTER 3: PLATE TECTONICS CONTINENTAL DRIFT o WEGENER o JIGSAW-PUZZLE FIT OF CONTINENTS ON BOTH SIDES OF THE ATLANTIC OCEAN, AS WELL AS ROCK AGES, FOSSIL EVIDENCE AND GLACIAL DEPOSITS, INDICATE THAT THOSE CONTINENTS WERE ONCE PART OF PANGAEA o THOUGHT CONTINENTS FLOATED ACROSS THE SOLID OCEANIC CRUST AND WERE DRAGGED ALONG BY THE TIDAL FORCED OF THE SUN & MOONTOO WEAK TO MOVE CONTINENTSPROBLEM: NO SIGNIFICANT FORCE TO MOVE CONTINENTS o MID ATLANTIC RIDGE= DISCOVERY OF A RIFT(DEEP, CRACKLIKE VALLEY) RUNNING DOWN ITS CENTER (THARP) ALMOST ALL EARTHQUAKES IN ATLANTIC OCEAN OCCUR HERE; SINCE EARTHQUAKES ARE GENERATED BY FAULTING = RIFT WAS TECTONICALLY ACTIVE FEATURE o HESS AND DIETZ EXPLAINED HOW THE CONTINENTS COULD DRIFT APART THROUGH THE CREATION OF NEW LITHOSPHERE AT MID- OCEAN RIDGES o SEAFLOOR/ OCEAN CRUST IS BEING RECYCLED DUE TO INTENSE VOLCANOES AND EARTHQUAKES (RING OF FIRE- MARGINS OF THE PACIFIC OCEAN BASIN) THEORY OF PLATE TECTONICS o RIGID LITHOSPHERE IS BROKEN UP INTO 13 LARGE PLATES THAT MOVE OVER EARTHS SURFACE o EACH PLATE RIDES ATHENOSPHERE AS DISTINCT UNIT o MANTLE CONVECTION= DRIVING FORCE OF PLATES DRIVEN BY HEAT FROM EARTHS DEEP INTERIOR HOT MATTER FROM MANTLE RISES CAUSING PLATES TO FORM AND DIVERGE WHERE PLATES CONVERGE, A COOL PLATE IS DRAGGED(SUBDUCTING PLATE) THE PLATE THEN SINKS, WARMS, AND RISES AGAIN UNDER MID-OCEAN RIDGES THERE IS BROAD, SPREAD OUT RISING MANTLE o ASTHENOSPHERE IS THE HOT, DUCTILE AND WEAK LAYER OF THE UPPER MANTLE WHERE PLATES SLIDE ; LITHOSPHERE IS THE STRONG, RIGID SHELL ABOVE THE ATHENOSPHERE CONVERGENT BOUNDARIES o PLATES COME TOGETHER AND 1 PLATE IS RECYCLED INTO MANTLE (PLATE AREA DECREASES) o OCEAN-OCEAN OCEANIC PLATE THAT IS MOST DESNSE (OLDER &COLDER) DESCENDS BENEATH THE OTHER IN A PROCESS KNOWN AS SUBDUCTION; LITHOSPHERE OF SUBDUCTING PLATE SINKS INTO ATHENOSPHERE AND IS RECYCLED BY MANTLE CONVECTION SYSTEM FORM DEEP-SEA TRENCHES SLAB DESCENDS DEEPER, PRESSURE ON IT INCREASES; WATER TRAPPED IN ROCKS IS RELEASED AND RISES INTO THE ASTHENOSPHERE ABOVE THE SLAB CAUSING MANTLE TO MELT AND FORMING VOLCANOES AND ISLAND ARCS o OCEAN-CONTINENT OCEANIC CRUST IS SUBDUCTEDDS LINE OF VOLCANOES ARE FORMED IN THE MONTAIN BELTS BEHIND THE TRENCH DUE TO AN INCREASE IN PRESSURE THAT RELEASES WATER AND MELTS ROCKS ABOVE IT ANDES ARE FORMED ON CONTINENTAL SIDE OF THIS BOUNDARY o CONTINENT-CONTINENT DOESNT SINK INTO MANTLE IT IS SLIGHTLY SUBDUCTING CAUSING CRUST TO THICKEN AND MOUNTAINS TO FORM SEVERE EARTHQUAKES OCCUR ON SUBDUCTING PLATES; HIMAYALAS ARE AN EXAMPLE DIVERGENT BOUNDARIES o PLATES MOVE APART AND NEW LITHOSPHERE IS CREATED (PLATE AREA INCREASES) o OCEANIC PLATE SEPERATION MARKED BY MID-OCEAN RIDGES THAT EXHIBITS VOLCANISM, EARTHQUAKES AND RIFTING CAUSED BY TENSIONSAL FORCES OF MANTLE CONVECTION PULLING THE 2 PLATES APART SEAFLOOR SPREADS AS MAGMA WELLS UP INTO RIFTS TO FORM NEW OCEANIC CRUST...
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EXAM 2 STUDY GUIDE - CHAPTER 3: PLATE TECTONICS CONTINENTAL...

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