Name______________________________________________________________Per________Date________________
C O N T I N E N T A L D R I F T
ALFRED WEGENER- German scientist who thought of the idea of continental drift.
Had some clues, but could not prove why or how the continents drifted.
His hypothesis was rejected- people thought he was a “crazy, little man!”
PANGAEA- supercontinent, means “all land”
Land features
Fossils
Climate
EVIDENCE of CONTINENTAL DRIFT continents fit together like a puzzle, rock layers match up fossils of freshwater reptiles were found on different continents (ex. Mesosaurus) warm-weather plant fossils were found in cold climates (ex. Glossopteris)
SEAFLOOR SPREADING
SEAFLOOR SPREADING- occurs when the seafloor spreads apart along both sides of a mid-ocean ridge and magma
comes up and hardens creating new crust. The ocean floors move like conveyor belts carrying the continents long with them.
EVIDENCE of SEAFLOOR SPREADING
Molten Material
Magnetic Stripes
-new material is erupting along the mid-ocean ridges
-magma comes up and hardens to form new crust
-new crust pushes old crust further apart
-rock patterns on the ocean floor
-magnetized stripes
-iron in rocks lined up in the direction of Earth’s magnetic poles
-some point north, some point south
Drilling Samples -youngest rocks are found at mid-ocean ridges
-oldest rocks are farther away toward the continents
DEEP-OCEAN TRENCH- formed when the ocean floor plunges into deep underwater canyons
the ocean floor sinks back into the mantle at deep-ocean trenches (subduction)
this process takes tens of millions of years
SUBDUCTION- process by which the ocean floor sinks beneath another ocean plate or a continental plate and gets
recycled back into the mantle
MID-OCEAN RIDGE- forms at a divergent plate boundary where two oceanic plates are moving apart
looks like a giant scar or the seam of a baseball


Name______________________________________________________________Per________Date________________
Convergent Boundary ocean floor dives under continental plate forming
Divergent Boundary forms a deep-sea trench mid-ocean ridge magma comes up through the spaces and forms new crust subduction zone- ocean plate is being recycled into the mantle