Plate TectonicsChapter 4 Lesson 1 pg194

What are Earth’s layers? BrainPop- Earth’s Structure

Core- central part of the Earth Inner Core- made of solid metals Outer Core- made of liquid metals

Mantel- thick layers of solid and molten rock that lies around the core Upper Mantel- the top of the upper

mantel (solid rock) joins with the crust to form the lithosphere -the rest of the upper mantel (melted rock) is the asthenosphere

Lower Mantel- solid rock

What are Earth’s layers? Crust- the thin layer of solid rock that makes up the

outermost the Earth

All of the Earth’s liquid and solid water- including oceans, lakes, rivers, glaciers, and the water located underground- makes up the hydrosphere.

The Earth’s crust makes up the surface of the Earth. What does the surface include?

the continents and oceans

Geological features are also found on the surface. These are physical structures

such as rivers, lakes, and desserts.

Review What are the different layers of the Earth?

Earth’s Layers- Labeling Game

From which layer of Earth do people get most of their resources?

the crust

Which layer of the Earth is made up of all of the Earth’s solid and liquid water?

Hydrosphere

What is the lithosphere and what does the lithosphere rest on?

It is the crust and the top part of the upper mantel. It rests partly on melted rock that makes up the upper mantel called the asthenosphere.

Are the continents moving? About 100 years ago a German geologist, Alfred

Wegener noticed that the continents looked like pieces of a jigsaw puzzle.

His theory that at one time all of the continents were connected and then moved apart by some force became known as the Theory of Continental Drift.

Evidence-Mountains on the east coast of South America and the

west coast of Africa had the same types of rocks and the rocks were the same age

Plant and animal fossils were also found like this. The animals would not have been able to swim the span of the ocean. What would you have concluded?

Scientists have concluded that all of the continents were once a part of a a supercontinent called Pangaea.

More evidence supported this theory in the 1950s when scientists were mapping the floor of the Atlantic Ocean and found that there was an underwater mountain chain. On both sides of the mountain chain, the ocean floor was moving.

Review Continental Drift

Continental Drift2- (Click on the animated gifs)

What caused the scientists to conclude that Earth’s continents were once joined?

evidence from fossils and rocks

How might large pieces of land be able to move?

They would need to be on top of something that could move.

What would happen to the plants and animals on that large landmass?

Some would be on one part and the rest would be on the other.

What causes the ocean floor to

move? BrainPop- Plate Tectonics

Explain the theory that scientists call plate tectonics.

It is the theory that explains how forces deep within Earth can cause ocean floors to spread and continents to move.

This theory describes the lithosphere being made of huge plates of solid rock. The continents rest on these plates.

The almost-melted rock of the asthenosphere acts as a slippery surface on which the plates can move.

In the middle of the ocean when the plates move apart what is pushed up from the mantle towards the surface?

Magma- It is hot, melted rock.

The magma causes tension, or a stretch or push on the plates. What do you think the push does to the ocean floor?

This means that the ocean floor moves apart and separates the plates that the continents rest on. This process is called spreading.

What happens to the hot magma when it reaches the surface?

It cools and forms the mid-ocean ridge. These ridges are underwater mountain ranges.

As the ocean floor grows wider, the continents grow farther apart.

At the Mid-Atlantic Ridge Ocean, new seafloor crust is formed at the rate of about 1.5 inches per year. (Turn to pg 201 to see the image of the ocean floor spreading.)

Review Where is the newest ocean floor?

The part of the crust that makes up the mid-ocean ridges.

Review What do you notice about the plates?

Some of the plates are pushing against each other. Some of the plates are moving away from each other. Many of the locations where the plates push against each other are sites of mountain ranges.

What forces change Earth’s

crust? A transform boundary is when plates slide past each other.

A force called shearing causes rocks to break as plates rub past each other. When the rocks pile up, they form narrow ridges and valleys.

What do you think occurs when the plates rub against each other?

Earthquakes

Most transform boundaries are located on the ocean floor. The most noticeable one on land is the San Andreas Fault between the North American plate and the Pacific Plate.

Convergent boundaries are locations where plates collide.

Divergent boundaries are locations where plates move apart.

Boundaries Animated

A fault is a break or crack in the rock of the lithosphere along which movements take place. Faults are located along the boundaries between the tectonic plates.

Three kinds of faults

Three Faults- Animated

San Andreas Fault

What are the different types of

mountains? Folded Mountains are mostly made of rock layers that are folded together by compression. (Great Smoky Mountains and the Himalayas in Asia)

Fault-Block Mountains are made of huge tilted blocks of rock separated from the surrounding rock by faults. (Sierra Nevada and the Teton Range)

Folded Mountains Fault-Block Mountains

Review

Review Site- Click on Each Topic from Intro. to Slip, Slide, and Collide

National Geographic- Plate Tectonics

Ology- Plates on the move

Plate Boundary map

Earth Floor- Pate Tectonics