Inside EarthChapter One

Section 1 Plate Tectonics

1.1 Earth’s InteriorKey Concepts

How have geologists learned about Earth’s inner structure?Geologists use two main types of evidence:a.Direct evidence – Look at rocksb.Indirect evidence – Seismic waves

1.1 Earth’s InteriorKey Concepts

What are the characteristics of Earth’s

Crust – The layer of rock that forms Earth’s outer surface.

Mantle – The layer of hot, solid material between earth’s crust and core.

Core – The center of the planet Earth.

1.1 Earth’s Interior Key Terms

• Basalt – A dark, dense, igneous rock with fine texture, found in ocean crust.

• Granite – A usually light-colored igneous rock that is found in continent crust.

• Lithosphere – A ridged layer made up of the uppermost part of the mantle and the crust.

• Asthenosphere – The soft layer of the mantle on which the lithosphere floats.

1.1 Earth’s InteriorKey Terms

• Outer core – A layer of molten iron and nickel that surrounds the inner core of Earth.

• Inner core – A dense sphere of solid iron and nickel at the center of the Earth.

1.1 Earth’s Interior Key Terms

• Seismic waves – Vibrations that travel through Earth carrying the energy released during an earthquake.

• Pressure – The force exerted on a surface divided by the area over which the force is exerted.

1.1 Earth’s InteriorA Journey to the Center of Earth

• Three main layers are the crust, the mantle, and the core

• Temperature – At the start the temperature is cool until approximately 20 meters. Then it begins to grow warmer. For each 40 meters the temperature rises 1* Celsius.

• Pressure - Because of the weight of the rock above the pressure increases the deeper you go.

1.1 Earth’s Interior

The CRUST – This is the Earth’s outer skin.The ocean crust is thinner, denser, dark

Mostly Basalt

The continent crust is thicker, lighter, less denseMostly Granite

1.1 Earth’s InteriorThe MANTLE – About 40 Kilometers beneath the

surface. Approximately 3,000 kilometers thickThis layers is very hot and solidThe mantle had TWO (2) main layers1-Lithosphere = upper mantle, similar to the crust.2-Asthenosphere = hotter increase pressure less

rigid, like road tar can bend like plastic.3-Lower mantle = solid all the way to the core,

1.1 Earth’s Interior

The CORE Is mostly iron and nickelIt has two layersOuter core – a layer of molten liquid rock (the movement of this liquid outer core layer is what gives earth

a magnetic field)Inner core – a dense ball of solid metal

Inside EarthChapter One

Section 2 Convection & the Mantle

1.2 Convection and the MantleKey Concepts

• How is heat transferred?• What causes convection currents?• What causes convection currents in Earth’s

mantle?

1.2 Convection and the MantleKey Terms

• Radiation• Conduction• Convection• Density• Convection currents

1.2 Convection and the MantleTypes of Heat Transfer

• Radiation

• Conduction

• Convection

Inside EarthChapter One

Section 3 Drifting Continents

1.3 Drifting ContinentsKey Concepts

• What was Alfred Wegener’s hypothesis about the continents?

• What evidence supported Wegener’s hypothesis?

• Why was Wegener’s hypothesis rejected by most scientists of his day?

1.3 Drifting ContinentsKey Terms

• Continental drift• Pangaea• fossil

1.3 Drifting ContinentsContinental Drift

• Wegener’s hypothesis:• All the continents were once joined together

in a single landmass and have since drifted apart.

• Landmass called Pangaea.

1.3 Drifting ContinentsEvidence

• Evidence from land features• Evidence from fossils• Evidence from climate

1.3 Drifting ContinentsRejected

• Wegener was not able to explain what force could possibly cause the continents to move.

Inside EarthChapter One

Section 4 Sea-floor Spreading

1.4 Sea-floor spreadingKey Concepts

• What is the process of sea-floor spreading>• What is the evidence for sea-floor spreading?• What happens at deep-ocean trenches?

1.4 Sea-floor spreadingKey Terms

• Mid-ocean ridge• Sea-floor spreading• Deep-ocean trench• Subduction• sonar

1.4 Sea-floor spreadingMid-ocean ridge

1.4 Sea-floor spreadingSea-floor spreading

The sea floor spreads apart along both sides of the mid-ocean ridge.

1.4 Sea-floor spreadingEvidence for Sea-floor spreading

• Evidence from molten materials• Evidence from magnetic stripes• Evidence from drilling samples

1.4 Sea-floor spreadingSubduction at Trenches

• Process where ocean floor sinks beneath a deep ocean trench.

Inside EarthChapter One

Section 5 Theory of Plate Tectonics

1.5 Theory of Plate TectonicsKey Concepts

• What is the theory of plate tectonics?• What are the three types of plate boundaries?

1.5 Theory of Plate TectonicsKey Terms

• Plate –A section of the lithosphere that slowly moves over the asthenpsphere. Carrying pieces of continental and

oceanic crust.• Scientific theory- A well-tested concept that explains a

wide range of observations.• Plate tectonics- The theory that pieces of Earth’s

lithosphere are in constant motion driven by convection

currents in the mantle.

1.5 Theory of Plate TectonicsKey Terms

• Fault – A break in Earth’s crust where masses of rock slip past each other.

• Rift valley – A deep valley that forms where two plates move apart.

1.5 Theory of Plate TectonicsKey Terms

• Divergent boundary

• Convergent boundary

• Transform boundary

1.5 Theory of Plate TectonicsDivergent Boundaries

• Divergent boundaries Two plates move apart.

1.5 Theory of Plate TectonicsConvergent Boundaries

• Convergent boundary – plates move into each other. There are two possible outcomes.

They rise up into mountains when both plates are equal in density. Himalayan mountains.

Or the heavier denser plate (ocean) slides under the lighter (continent) less dense plate

1.5 Theory of Plate TectonicsTransform Boundaries

• Transform boundary – slide past each other in opposite directions. They stay on the same level. No rise or sinking.