Unit 2

The Earth’s relief

Teacher Rocío González

1- The Earth’s crust

Magma

Oceans andcontinents

Activities

Exercises 2 on page 24, 3 and 5 on page 25 in your notebooks.

2- What is the Earth’s relief?

Ocean relief

Ocean relief

ActivitiesExercises 1 to 4 on page 27.

3- Internal forces of reliefContinental drift theoryContinental drift was a theory proposed in 1912 by Alfred Wegener which postulated the movement of continents. This theory is a part of the concept of plate tectonics. Continents have been drifting for hundreds of millions of years.Nowadays there exists lots of evidence for continental drift. The most obvious is the way in which the continents seem to fit jigsaw-like (for example Africa and South America) together when looked at on a map. More scientific evidence comes in the form of plant and animal fossils of the same age found around different continent shores, suggesting that they were once joined.

Pangaea

Pangaea (/pænˈdʒiːə/) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras, forming about 300 million years ago. It began to break apart around 200 million years ago. The single global ocean which surrounded Pangaea is accordingly named Panthalassa.

Tectonic platesA theory that explains the global distribution of geological phenomena such as seismicity, volcanism, continental drift, and mountain building in terms of the formation, destruction, movement, and interaction of the earth's lithospheric plates.

Faults and folds

What are volcanoes and earthquakes?

Geyser and hot springs

Earthquakes

***Go to page 33 for a little advice!

ActivitiesExercise 1 on page 28.Exercises 2, 3 and 4 on page 29.And finally, investigate! Exercise 5 on page 29, and 11 on page 33.

4- How does relief change?CHANGES IN RELIEFRelief is also shaped by external forces: temperature, water, wind and human action. There are 3 processes: EROSION: the wearing away of rocks and other deposits on the earth's surface by the action of water, ice, wind, etc.TRANSPORTATION: the eroded material is transported by water or wind.DEPOSITION: the material is deposited in areas where sediments accumulate.

CAUSES OF EROSION

The course of a river

Canyons

SEDIMENTATION

Deltas

Cliffs

Sand dunes - wind effect

Temperature

Human action. Reservoirs

Think about it. Terraces. Inca terraces.

Think about it. Ski stations.

Think about it. Tunnels.

Think about it. Highways.

ActivitiesExercises 1 to 4 on page 31.Exercises 1, 4, 8, and 9 on pages 32-33.

Topographic profileA topographic profile is a cross sectional view along a line drawn through a portion of a topographic map. In other words, if you could slice through a portion of the earth, pull away one portion, and look at it from the side, the surface would be a topographic profile.

Practice with topographic profiles

Exercises 1 and 2 on page 34.

Work with maps. Activities. Exercises 1 to 5 on page 35.