Plate Tectonics

accepted by the vast majority of scientists accepted by the vast majority of scientists Earth’s interior is made up of two layers: the lithosphere comprising the crust and the solidified uppermost part of the mantle. Earth’s interior is made up of two layers: the lithosphere comprising the crust and the solidified uppermost part of the mantle. Mantle is on top of the asthenosphere, a very thick viscous fluid layer Mantle is on top of the asthenosphere, a very thick viscous fluid layer Lithosphere “floats” on asthenosphere. Lithosphere “floats” on asthenosphere.

Plate Tectonics Lithosphere broken into tectonic plates Lithosphere broken into tectonic plates 10 major and many minor plates 10 major and many minor plates

How Plates Move. Convection currents: heating causes a material to expand and rise, then cooling causes the material to contract and fall. Convection currents: heating causes a material to expand and rise, then cooling causes the material to contract and fall. Lithosphere on a metaphorical treadmill. Lithosphere on a metaphorical treadmill.

3 Types of Plate Boundaries 1. Transform Boundaries 1. Transform Boundaries 2. Convergent Boundaries 2. Convergent Boundaries 3. Divergent Boundaries 3. Divergent Boundaries

Convergent Boundary 2 plates moving toward each other 2 plates moving toward each other Subduction Zone: one plate slides under another. Correlated with volcanoes. Subduction Zone: one plate slides under another. Correlated with volcanoes. Continental Collision: if two continental plates collide. EX: Himalayan mountains Continental Collision: if two continental plates collide. EX: Himalayan mountains

Transform Boundaries Plates grind past each other. Plates grind past each other. Fault line Fault line San Andreas San Andreas Earthquakes Earthquakes

Divergent Boundary 2 plates slide away from each other 2 plates slide away from each other Mid-ocean trenches Mid-ocean trenches Key concept supporting plate tectonics Key concept supporting plate tectonics

Pangaea Super continent believed to exist during prehistoric times. Super continent believed to exist during prehistoric times.

Breaking up of Pangaea First major break up of Pangaea occurred during the Triassic period. First major break up of Pangaea occurred during the Triassic period. Formation of Atlantic Ocean and Mississippi river occurred. Formation of Atlantic Ocean and Mississippi river occurred.

Breaking up of Pangaea 150 million years ago 150 million years ago South America break away from super continent South America break away from super continent India and Africa begin to move north India and Africa begin to move north

Breaking up of Pangaea million years ago million years ago North America and Greenland break away North America and Greenland break away India collides with Asia India collides with Asia Australia breaks away from Antarctica Australia breaks away from Antarctica