Theory of Continental Drift (pg 220-221)

• The Theory of Continental Drift states that all continents on Earth were once joined together as Pangaea, but then drifted apart.

• The theory was proposed by Alfred Wegener.

• Evidence for continental drift includes:– the shape of continents, – similar fossils, – Similar rock layers,– Sea floor spreading

• Continents and oceans are still drifting with the movement of tectonic plates.

Earth’s Layers (pgs. 215-217)• Under the atmosphere, there are 4 main layers of the Earth:

1. Crust 2. Mantle 3. Outer Core 4. Inner Core

• Scientists can study the travel times of energy waves to get clues about the kinds of materials that are inside of the Earth.

• If the energy wave moves slowly through the material, then we know that the material must be more dense.

• If the energy wave moves quickly through the material, what can we say about it’s density?

Earthquakes and Volcanoes (pgs. 228-231)

EARTHQUAKES • Earthquakes occur when pressure

that builds up along a fault is released.

• Earthquakes occur at fracture boundaries (where plates rub together).

VOLCANOES• A volcano is an opening in the surface of

one of Earth’s plates through which magma rises.

• Volcanoes occur at colliding boundaries and spreading boundaries. Some occur in the middle of the plate. That’s known as a hotspot. The Hawaiian Islands are hotspot volcanoes.

• The Earth’s lithosphere is broken into tectonic plates which can consist of both continental and oceanic crust.

• Earthquakes and volcanoes usually take place at plate boundaries (where those tectonic plates meet)

Earthquakes and Volcanoes (pgs. 228-231)• Earthquakes and volcanoes usually take place at plate boundaries (where

those tectonic plates meet).

• A volcano is an opening in the surface of one of Earth’s plates through which magma rises.

• Volcanoes occur at colliding boundaries and spreading boundaries.

• Some volcanoes occur in the middle of plates (called hotspots). Example: the Hawaiian Islands.

• The “Ring of Fire” is located along the plate boundary of the Pacific Plate. It is an area where most of the Earth’s volcanoes and earthquakes occur.

• Earthquakes occur at fracture boundaries (where plates rub together).

POD-Earthquakes and Volcanoes (pgs. 228-231)

• At what type of plate boundary do earthquakes occur? Explain the movement of the plates at that type of boundary.

• At which type of plate boundaries do volcanoes typically occur? Explain the movement of the plates at those types of plate boundaries.

Earthquakes occur at fracture boundaries. At this type of boundary plates rub against each other.

Volcanoes typically occur at spreading and colliding boundaries. At a spreading boundary plates move apart and at a colliding boundary plates move together.

Layer Name Definition Important Facts

atmosphere

crust

lithosphere

mantle

outer corethe liquid layer of Earth that surrounds the solid

inner core.

inner core

the innermost, solid layer of Earth.

-Made up of gases: nitrogen, oxygen, carbon dioxide, and water that cycle through the environment.(N2, O2, CO2, H20)

-solid-mostly oxygen-thinnest layer

-upper portion is solid -inner portion is liquid-mostly oxygen-thickest layer

--liquid -made mostly of iron

-solid -made mostly of iron-hottest layer

-rotates at a faster speed and in the opposite direction of the Earth creating a magnetic field

The blanket of gases that surround the Earth.

The outermost solid layer of the Earth.

The Earth’s crust and the solid portion of the mantle.

A thick layer of Earth just between the crust and the core that contains most of Earth’s

mass.

-broken into about 20 tectonic plates-float on top of the lower mantle because of convection

Lab ConversionsLayer Thickness (km) Thickness (hm)

Atmosphere 500 km

Continental Crust 38 km

Oceanic Crust 9 km

Mantle 2900 km

Outer Core 2221 km

Inner Core 1255 km

50 hm

3.8 hm

.9 hm

290 hm

222.1 hm

125.5 hm

Atmosphere Oceanic Crust ContinentalCrust

Mantle Outer Core Inner Core0

102030405060708090

100110120130140150160170180190200210220230240250260270280290300

Thic

knes

s (hm

)

Lithosphere (pgs. 218-219)

• The crust and the solid, upper portion of the mantle is known as the lithosphere.

• The lithosphere is broken into pieces called tectonic plates•Most plates contain both continental and oceanic crust.

• Tectonic Plates float on top of the mantle.

• The Theory of Plate Tectonics states that the lithosphere is broken into about 20 moving plates.

• Convection currents in the mantle cause tectonic plates to move.

• Plate movement creates landforms, causes earthquakes and volcanoes, and moves continents. These movements occur at plate boundaries (the edges of the plates).

• Convection currents and the spinning inner core create Earth’s magnetic field.

Lithosphere and Plate Tectonics (pgs. 218-225)

Plate Boundaries (pgs. 226-227)

• At a colliding boundary, plates come together and create• mountains, • trenches, • Volcanoes

• At a spreading boundary, plates move apart and create• rift valleys, • mid-ocean ridges (underwater volcano range), • Volcanoes

• At a fracture boundary, plates slide past each other and cause: • earthquakes

Theory of Plate Tectonics (pgs. 224-225)

•Convection currents in the mantle cause tectonic plates to move.

•Plate movement creates landforms, causes earthquakes and volcanoes, and moves continents.

•Convection currents and the spinning inner core create Earth’s magnetic field.