Investigation 4: Plate Tectonics Earth systems Investigation 4: Plate Tectonics

Lesson Essential Question Notes Lesson Essential Question What processes cause the Earth’s plates to shift?

Explain the evidence used to support the Theory of Plate Tectonics. Notes Lesson Objective Explain the evidence used to support the Theory of Plate Tectonics.

The Theory of Continental Drift Notes The Theory of Continental Drift - First Proposed by scientist, Alfred Wegener - The evidence that Wegener proposed to support the idea that the continents move is also evidence that there are plates on Earth that are in motion

The Theory of Continental Drift Notes The Theory of Continental Drift EVIDENCE PIECE 1: Continental Shapes The continents look as though they could fit together like pieces of a jigsaw puzzle

The Theory of Continental Drift Notes The Theory of Continental Drift EVIDENCE PIECE 2: Fossil and Rock Patterns Fossils and rocks found on continents that are oceans apart but match up perfectly

The Theory of Continental Drift Notes The Theory of Continental Drift EVIDENCE PIECE 3: Glacial Deposits A. When the continents are put together they show a streamlined motion of the glacier from southern Africa and Northern Australia outward. B. With the continents in their present positions, the deposits indicate erratic glacier motion. 

New evidence in support of plate tectonics Notes New evidence in support of plate tectonics

New evidence in support of plate tectonics Notes New evidence in support of plate tectonics EVIDENCE PIECE 4: Sea Floor Age Maps Scientists have discovered a distinct pattern in the age of oceanic crust

New evidence in support of plate tectonics Notes New evidence in support of plate tectonics The newest oceanic crust is in the center and gets progressively older as you move towards the continents in a distinct pattern, indicating that there is definite movement of the ocean floor.

Atlantic Ocean Sea Floor Spreading Map

Pacific Ocean

Indian Ocean

The Process of Seafloor Spreading Notes The Process of Seafloor Spreading Creation of New Oceanic Crust - Occurs at Mid-Ocean Ridges - Underwater chains of mountains found in the oceans - Youngest rocks on the ocean floor are found here

The Process of Seafloor Spreading Notes The Process of Seafloor Spreading Destruction of Old Oceanic Crust - Occurs in a process called Subduction - Old oceanic plates sink back into the mantle - Creates a Trench - a deep depression in the ocean floor

Plate Boundaries Notes Divergent Boundary Plates are moving away from each other Convergent Boundary Plates come together and collide Transform Boundary Plates slide past each other in opposite directions

New evidence in support of plate tectonics Notes New evidence in support of plate tectonics EVIDENCE PIECE 5: GPS and Satellites GPS stations set up all across the globe are moving toward or away from each other

What Causes Plate Tectonics? Notes What Causes Plate Tectonics? Convection Currents - Form in the Earth’s Mantle - Caused by the heat generated from radioactive decay of elements in the mantle and core