Chapter 5, Lesson 1 Continents A Drift
Continental Drift - Alfred Wegner proposed all continents were joined together called Pangaea.
- Evidence from continents fitting together like a puzzle.
- Evidence from fossils found on different continents - example plant called Glossopteris or animal called
Mesosaurus
- Evidence from climate continents moved away from the equator example: Antarctica was warm at one time.
All evidence was rejected.
Chapter 5, Lesson 2 Sea-Floor Spreading
Mid-Ocean Ridges
Sea-Floor Spreading
Deep-Ocean
Trenches
Subduction
-Form long chains of mountains on the ocean floor.
-Sonar is a sound wave that was used to map the ocean floor.
-Form the longest mountain ranges on Earth.
- Mid-Atlantic Ridge and East Pacific Rise.
-New crust is added, it is hotter and less dense.
- New material erupts from inside Earth, cools and hardens.
- Mirror image on both sides of the spreading.
- Evidence: pillow lava, magnetic striping, and drilling samples.
-Where part of the ocean floor sinks back into the mantle.
-Where the crust is older, colder and denser.
- Oceanic crust sinks down beneath the trench into the mantle.
-Takes about 200 million years for the ocean floor to be renewed.
-The Atlantic Ocean is expanding and the Pacific Ocean is getting smaller.

Chapter 5, Lesson 3 The Theory of Plate Tectonics
Stress
Faults
Folding
Uplifting
Summary:
Plate Tectonics
Boundaries
- Plates move in three ways: divergent boundary (away), convergent boundary (together) and transform boundary
(slip past each other in opposite directions).
-Driven by convection currents in the mantle.
-Faults are breaks in Earth’s crust are formed along plate boundaries.
- Oceanic crust is more dense (heavier) than continental crust (lighter)
Divergent boundary (draw and label picture pg. 177) and give an example.
Convergent boundary (draw and label picture pg. 178) and give an example.
Transform boundary (draw and label picture pg. 179) and give an example.
Chapter 5, Lesson 4 Forces in Earth’s Crust
-
Tension is where Earth’s crust is pulled apart
Compression two of Earth’s plates come together causing folding or breaks.
- Shearing is where two of Earth’s plates move in opposite directions.
-Normal fault is where rock is pulled apart by tension in Earth’s crust.
-Reverse fault is where compression pushes the rock of the crust together.
-Strike-Slip fault is where the rocks on either side of the fault slip past each other in opposite directions.
- Forms when compression shortens and thickens
Earth’s crust (smashes together with a lot of force)
-Anticline is the top of the fold (mountains)
-Sincline is the bottom of the fold (valley)
-Forces that raise mountains also uplift, or, create a plateau.
-Plateau is a large area of flat land elevated high above sea level.
Divergent boundary-tension stress-normal fault
Convergent boundary-compression stress-reverse fault.
Transform boundary-shearing stress-strike-slip fault.

Chapter 5, Lesson 5 Volcanoes and Plate Tectonics
Volcanoes -Form along plate boundaries where they converge or diverge.
-Ring of Fire is a major belt of volcanoes.
-Hot spots form islands where volcanoes forms above it.
Chapter 5, Lesson 6 Volcanoes Eruptions
Volcano
Two types of
Eruption
Hazards
Stages
- A system of passageways through which magma moves.
- Parts: magma chamber, pipe, vent, lava flow, crater
- Erupts with a great force of expanding gases that pushes magma to either flow or explode out of the vent.
- Quiet eruptions are hot and/or low in silica, thin and runny, and flows easily. Has two types of lava.
* Pahoehoe forms from fast-moving hot lava that is thin and runny and looks like a solid mass of ropelike coils.
* Aa forms from lava that is cooler and thicker and slow moving. Its surface is rough consisting of jagged lava chunks.
- Explosive eruptions are high in silica, thick and sticky. Explodes violently. Small pieces are called ash and large pieces called bombs.
-Can cause damage far fr om the crater’s rim (fire), hot ash and rocks.
-Pyroclastic flow is a mixture of hot gases, cinders, ash and bombs that form a fast moving flow down the volcano.
-Active or live, means it is erupting or shows signs that it may erupt in the near future.
- Dormant or sleeping, means that it could be awaken in the future or become active.
-Extinct or dead, means the volcano is unlikely to erupt again.