PLATE TECTONICS 1 Tectonic Plates

TECTONIC PLATES REVIEW Tectonic Plates: a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle What type of crust… Continental Crust Oceanic Crust Both 2

MAJOR TECTONIC PLATES REVIEW 1.Pacific plate 2.North American plate 3.Cocos plate 4.Nazca plate 5.South American plate 6.African plate 7.Eurasian plate 8.Indian plate 9.Australian plate 10.Antarctic plate 3

TECTONIC PLATE CLOSE-UP REVIEW Consist of upper part of mantle Oceanic Crust (thinnest) Continental crust (thickest) 4

THE THEORY OF PLATE TECTONICS Plate tectonics: theory that the Earth’s lithosphere is divided into tectonic plates that move around on top of the asthenosphere. 5

TECTONIC PLATE BOUNDARIES Boundary: a place where tectonic plates touch Convergent Divergent Transform 6

CONVERGENT BOUNDARIES Convergent boundary: the boundary formed by the collision of two lithospheric plates Continental-Continental Continental-Oceanic Oceanic-Oceanic 7

DIVERGENT BOUNDARIES Divergent boundary: the boundary between two tectonic plates that are moving away from each other Forms mid ocean rigids 8

TRANSFORM BOUNDARIES Transform boundary: the boundary between tectonic plates that are sliding past each other horizontally Faults 9

POSSIBLE CAUSES OF MOTION Remember that the asthenosphere flows very slowly… Changes in density within the asthenosphere Caused by the outward flow of thermal energy from deep within the Earth When rock is heated, it expands, becomes less dense, and tends to rise to the surface. When rock gets near the surface, the rock cools, becomes more dense, and tends to sink 10

THREE POSSIBLE DRIVING FORCES OF PLATE TECTONICS Ridge Push: at mid-ocean ridges, the oceanic lithosphere is higher than it is where it sinks into the asthenosphere. Because of ridge push, the oceanic lithosphere slides downhill under the force of gravity. 11

THREE POSSIBLE DRIVING FORCES OF PLATE TECTONICS Convection: hot rock from deep within the Earth rises, but cooler rock near the surface sinks. Convection causes the oceanic lithosphere to move sideways and away from the mid ocean ridge. 12

Slab Pull: because oceanic lithosphere is denser than the asthenosphere, the edge of the tectonic plate that contains oceanic lithosphere sinks and pulls the rest of the tectonic plate with it in a process call slab pull. THREE POSSIBLE DRIVING FORCES OF PLATE TECTONICS 13