Unit 2: The formation of the Earth's relief

1. Unit 2: The formation of the Earth’s
Relief
In this unit we are going to study the formation
of the relief of the Earth.

2. The Earth’s
Relief
Process of
Formation
Process of
Erosion
Internal Forces External Forces
• Continental Drift
• Tectonic Plates
• Orogeny
• Volcanoes
• Earthquakes
• Erosion, transport and
deposition
• Water (rainfall, rivers,
seas…)
• Wind
• Plants
• Human Beings
Landforms

3. 1. What is the Continental Drift?
• Continental drift (deriva continental) is a
theory that says that the continents have been
moving (or drifting) all along the geological
eras.
Click on the image
Extra information: this theory
was developed by Alfred
Wegener in 1912.

5. 2. What are the tectonic plates?
• Tectonic plates are the different blocks in
which the lithosphere is divided.
• They can move apart or collide, creating or
destroying relief.
• They are responsible of the creation of
mountains (orogeny), volcanoes and
earthquakes.
Extra information: lithosphere is a layer of the
Earth that is made up of the crust and the upper
part of the mantle.

6. Extra information: Why do the Tectonic
plates move?
There are many theories but they are not totally clear
and confirmed yet.
One says that it happens because of the convective
movement of the mantle (which is hot and liquid).
Other theory says that it happens because of the
attraction forces (tidal forces) of the Sun and the Moon.
And we can not forget that the Earth is spinning at a
speed of 220 km/sec approx., that the lithosphere is
divided in many parts called tectonic plates and that
this tectonic plates are floating on the mantle.

7. Tectonic Plates

9. Oceanic Ridge
(Dorsal oceánica)

11. 3. Cross-section of the Earth’s relief

12. Rift of Iceland

13. Mariana Trench (11.034 m of depth)

14. What are the parts of a volcano?
1. Gases
2. Rocks
3. Lava
4. Crater
5. Molten magma
6. Side Vent
3. Cone

15. Mount Etna

16. El Volcán de Sta Margarita es uno de los más importantes del
sector, de 682 metros de altitud y su boca tiene un perímetro
de 2.000 metros. En el centro del llano formado por el cráter
se encuentra la Iglesia de Santa Margarita, de origen
románico. Su última erupción data de hace 11.000 años

17. Richter Scale
Seismograph

18. 4. Landforms
• Study the
landforms of your
textbook

19. External Forces
5. What are the external forces?
The external forces are the external agents that
modify the relief of the Earth through the
process of erosion, transport and deposition.
(Erosión, transporte y sedimentación).

20. What would you write in each box?
Erosion
Transport
Deposition

21. 6. What external forces modify the relief?
The external forces or erosive agents are:
• Temperature
• Wind
• Rainfall
• Rivers
• Sea
• Glaciers
• Groundwater (aguas subterráneas)
• Living things (plants, animals and human beings)

22. What external force eroded this rock?
Salar de Uyuni, Bolivia

23. Balanced Rock,
Garden of the Gods
Colorado, USA

24. Boulders - South Island - New Zealand

25. Bryce Canyon National Park - Utah, USA

26. White Cliffs of Dover

27. THE CATHEDRALS´ BEACH (Lugo)

29. The Giant's Causeway - Northern Ireland, UK

34. Glacier of Alaska

35. Bear Glacier, Alaska

36. Parque Nacional de Ordesa, Aragón

37. Las Médulas