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Chapter 1, Pgs. 50-55

Most of this is NOT in your book!

May the force be

within the Earth!

Q: What is geology?

A: The study of the earth’s physical structure and history.

What does the inside of the earth look like?

1.Core: Consists of very hot metal, mainly iron mixed with some nickel. Inner

core is thought to be dense and solid. Outer core is

molten or liquid.

2. Mantle: A thick layer of rock. About 1800 miles thick.

Contains pockets of magma or melted rock.

3.Crust: Rocky surface layer. Like frosting on a cake. 5 to 22

miles thick. Natural forces interact with and affect the

earth’s crust, creating landforms.

Q: How much of the earth is water?

A: 70% of earth is covered with water.

Four Major Types of Landforms:

Mountains

Hills

Plateaus

Plains

Landforms are shaped by the internal forces that originate in the earth’s interior:

1.Volcanism

2. Earthquakes

Volcanism – movement of magma inside the earth, when molten rock (lava) inside the earth breaks through the earth’s crust it forms a volcano

Earthquake – movement of rock layers that bend or break the earth’s crust. Folds and faults occur.

Q: How do we explain these folds/faults?

A: The Plate Tectonics THEORY:

The earth’s outer shell (mantle and crust) is composed of large plates whose slow and steady

movement explains earthquakes and volcanic activity.

The Plate Tectonics Theory is based in two other theories…

Continental Drift Theory and the Seafloor Spreading Theory.

Continental Drift Theory: Theory proposed by Alfred Wegener in 1912, where he suggested the idea that over- - - - - - - - - - - >

Pacific Ocean – Ring of Fire• Humans encounter tectonic

forces most directly as earthquakes and volcanoes

• Volcanoes and earthquakes are particularly common around the edges of the Pacific Ocean

• Area is known as the Ring of Fire

Four Major Types of Plate Movement

1. Subduction: Oceanic plate goes under a continental plate.

2. Converging: Two continental plates meet each other creating mountains.

3. Faulting: Plates moving past each other creating earthquakes.

4. Seafloor Spreading: The ocean floor is not flat. Molten rock (magma) from the mantle rises up to the underwater ridges and breaks through a split at the top of the ridge - called a rift valley. Example: Mid-Atlantic Ridge

Sea-Floor Spreading

http://www.worldatlas.com/aatlas/infopage/tectonic.htm

Plate Tectonics MapAssignment