1. Structure and Composition of the Geosphere

8 The Earth’s internal dynamics

Worksheet – Student B 1. Structure and composition of the geosphere

1. Classify the features in the cloud. Methods for studying the geosphere Direct Indirect

2. Work with your partner to fill in the missing information.

8 The Earth’s internal dynamics

3. Identify and correct the false statements.

Geochemical or static model It explains the Earth’s structure by splitting it into concentric layers according to their density. __ The core is the deepest layer which is made up of iron and nickel and is where the Earth’s magnetic force is created. __

The outer core is in a solid state whereas the inner core is liquid. __ The Earth’s magnetic field is due to the outer core’s convection currents. __ The mantle is the rocky, thin, solid outer layer which is divided into the upper and the lower mantle. __ The lower mantle, denser than the upper one, is highly compacted due to the high pressure exerted by the layers above it. __

The continental crust consists mainly of olivine and peridotite, and its thickness is constant. __

The oceanic crust, made of basalt and gabbro, forms the ocean floors. __

4. Put the blocks of text in the correct order. Seismic discontinuity The transition zones – are known as - with different properties – between two layers - seismic discontinuities ______They are called seismic discontinuities – they change velocity and direction - cross them to pass through matter - with different properties, - because when seismic waves ______This phenomenon, - is called refraction - which all waves undergo, ______

8 The Earth’s internal dynamics

5. Fill in the gaps in the text using the terms below it. ______refers to the fact that the Earth ______like a perfect spherical ______, although it is fact an ______. This property determines the ______that make up geological processes such as ______arcs produced by the ______of tectonic plates, or the constant ______of Earth’s ______.

Movement - Sphericity - Island - Ellipsoid - Behaves - Trajectory - Dynamics - Shape - Orbit ______is the state of ______in the Earth’s surface produced by variations in ______at different points. Based on Archimedes’ ______, it causes vertical, or ______, movements because the ______parts of the crust tend to ______and the ______parts tend to ______. Isostasy is a key factor in creating the ______of the Earth’s surface. This elevation process is followed by a process of ______and wearing down, resulting in the isostatic ______that maintains the planet’s sphericity.

equilibrium - epirogenic - balance - sink - contours - isostasy - denser - lighter - principle - rise - density - erosion

6. Circle the correct option.

The Earth acts as a giant/small magnet. This force comes from conduction/convection currents in the inner/outer core. Earth’s magnetic field extends beyond the exosphere/mesosphere and attracts charged particles in the solar wind which do not enter Earth’s magnetosphere/ionosphere. This helps allow the development of life in our planet.

Earth’s gravitational/electric field is produced by the planet’s charge/mass, according to Newton’s/Archimedes’ law of universal gravitation. It attracts all nearby masses towards its crust/centre and its internal structure is organised into layers, according to their relative chemical composition/density. It also governs geological processes, the atmosphere and biosphere/hydrosphere and the development of life.

7. Correct the 7 spelling mistakes.

The geodinamic modell divides the insid of the Earth into seberal zones, on the bases of two criteria: their phisycal estate and their behaviour or dynamic.

8 The Earth’s internal dynamics

8. Complete the diagram.

9. Answer the multiple choice questions.

Geothermal gradient Geothermal gradient is the continuous increase in temperature in the Earth in relation to… a) Decreasing depth. b) Varying layers’ composition. c) Increasing depth. Dynamics in the different layers of the Earth result from… a) The movement of the tectonic plates. b) The heat flowing from the centre of the planet to the surface. c) The Earth’s magnetic field. The heat transported from the outer core comprises… a) Residual heat from the planet’s formation. b) Heat as a result of thermonuclear reactions in its radioactive components. c) a) and b).

8 The Earth’s internal dynamics

2. Internal geodynamics

10. Listen and fill in the gaps in the text.

Internal geodynamics is the study of the Earth’s internal ______, their behaviour and their ______for geological phenomena and ______, including mountain formation, ______and volcanicity.

______theories explain the formation of orogens and the ______of the land.

______theories were formulated during the 19th and early 20th centuries. They base their explanation of the ______of mountains and geological ______on the assumption that the ______have always been in the ______position that they are ______in.

Fixist theories propose that Earth’s continents have ______the same geographical ______throughout history.

These theories were ______by the arguments of ______theories. Information ______in the 1960s from ocean ______and using the seismic ______supported mobilist theory, as explained in the ______model of the Earth’s internal structure.

11. Identify the false statements and correct them.

Mobilist theories propose that the continents have always been in the same position that they are currently in. __

Alfred Wegener was an early proponent of the idea that the geosphere is a dynamic system. __

Convection currents do not take part in the movement of the continents. __

According to the continental drift theory, the lithosphere is divided into several plates which __ are in constant movement in relation to one another. The discovery of ocean ridges and seafloor spreading confirmed the hypothesis of convection currents as responsible for the continents’ movement. __ Pangaea was a supercontinent formed by today’s continents. __

8 The Earth’s internal dynamics

12. Solve the cryptogram. Then work with your partner to fill in the missing information in the figure.

Continental drift theory

Evidence

Assumptions

8 The Earth’s internal dynamics

3. Seafloor spreading

13. Fill in the gaps in the text using the terms below it.

In 1960, geologist Harry Hess proposed that matter ______up from the ______along oceanic ______creates new crust.

______spreading theory states that new ______is formed at the oceanic ridges when new material rises and is ______to the sides of the ridge, thus increasing the ______of the ocean floor.

At an oceanic ridge, ______pushes ______to either side, separating it and raising the ______of the ridge. Rock on either ______of a ridge has the same ______orientation and forms ______parallel bands.

level - crust - pressure - symmetrical - rising -pushed - mantle - magnetic - magma - ridges - area - side - seafloor

14. Circle the correct option.

Evidence for seafloor spreading

1) Age of gabbro/basalt rocks 2) Palaeomagnetism 3) Presence of sediment on ocean floors The older/younger the rocks of The Earth’s magnetic the ocean ridges/floors are, the field is stable/unstable, Sediment is not distributed closer/further they lie from and its polarity has evenly on the ocean floor: oceanic ridges and the inverted from time to there is no sediment/ closer/further they lie to the time in the course of sediment along ocean ridges. continents. history. These changes in The amount and density/size polarity are of sediment increases away recorded/collected in from the ridges/continents rocks that contain the and towards the mineral ridges/continents. This olivine/magnetite, shows that the ocean floor which, as it solidifies, moves and slowly accumulates orients itself according to sediment over time. the Earth’s magnetic field.

8 The Earth’s internal dynamics

4. Plate tectonics

15. Listen and fill in the gaps in the text.

Plate tectonics theory ______the lithosphere into lithospheric ______which are in ______movement.

It is based on the following ______principles:

 Lithospheric plates move because of ______in the Earth’s ______.

 The lithosphere is made up of the ______and the ______mantle, which form a dynamic ______, broken up into lithospheric or tectonic plates.

 Convection affects the whole mantle, so its movement ______with it the part of the lithosphere ______on it.

The ______that supports plate tectonics is:

1. ______of seismically active ______: These are areas with ______levels of geological ______, including volcanoes and ______. The Circum-Pacific Belt and the Eurasian- Melanesian Belt both measure ______of kilometres and are marked by ______and faults.

2. ______of oceanic ______: They coincide with areas of high geological activity. This activity maintains the ______of the Earth’s crust by ______it at convergent boundaries and creating it at ______boundaries.

16. Complete the diagram.

8 The Earth’s internal dynamics

17. Complete the table.

Types of plate boundaries Plate Characteristic Associated Diagram Examples boundaries relief phenomena

Divergent or

constructive

Convergent or

destructive

Transform or

conservative

8 The Earth’s internal dynamics

5. Consequences of the Earth’s internal dynamics

18. Solve the cryptogram.

19. Solve the crossword. Across 2. They are formed when continental plates separate, resulting in the crust sinking. 4. The underground point where the earthquake's focus lies. 6. Waves that occur on the surface, causing horizontal movements from one side to the other. 8. It occurs when continental plates collide, creating folds and deposits. 9. The spread of vibrations through matter which are emitted by a seismic movement. Seismic movements are the result of elastic energy accumulated in the Earth's crust being released. 10. The point on the ground directly above the earthquake's focus. 11. Body waves that pass through all matter, solid or liquid.

Down 1. Surface waves whose movement is elliptical. 3. Body waves that pass through solid matter. 5. They form when oceanic plates separate and break the ocean floor. 7. Sudden movements of the Earth's surface. They occur in unstable parts of the crust and, in particular, at plate boundaries.

8 The Earth’s internal dynamics

20. Listen and fill in the gaps in the text.

Measurements of earthquakes ______measures the elastic ______released in an earthquake. It is calculated by measuring the ______registered by a ______located at least 100 km from the ______. It is measured using the ______scale, which assigns a ______from 2 to 10 according to the ______of energy released. ______measures the ______of land movement and the ______of vibration recorded in a particular ______. It is measured using the ______intensity scale, which has 12 ______, from I to XII. A ______is an instrument used to record ______movement, and its results are displayed on a ______. P waves arrive ______as they spread ______, followed by the S waves. They are both ______waves. The ______waves arrive last: they come from the ______, and they are the most ______, because they cause ______to the Earth’s surface.

21. Circle the correct option.

Seismic waves: a way of studying the Earth’s interior The seismic method means studying the outside/inside of the Earth by applying our knowledge of the properties of seismic waves. P and S waves vary in velocity/intensity and direction when they go through layers with different properties or chemical/physical states, giving rise to shadow/dark zones. These changes help us work out the location/depth at which the Earth’s properties change, as sharp/smooth changes coincide with seismic continuities/discontinuities. We can also use this method to work out the general properties of the lithosphere’s/geosphere’s internal layers.

22. Fill in the gaps in the text using the terms below it.

Volcanism and volcanoes

A ______is a geological ______on the Earth’s surface. It is a ______through which matter from inside the Earth, known as ______, rises and is released.

Volcanoes are located in ______active parts of the planet, such as new ______ranges, oceanic ______, ______zones and so-called ‘______spots’. In other words, they are ______to lithospheric plate ______. They release matter to the Earth’s surface during volcanic ______.

eruptions - seismically - magma - mountain - subduction - volcano - boundaries - linked - fissure - hot - structure - ridges

8 The Earth’s internal dynamics

23. Match the information and label the picture.

Structure of a volcano  Crater  Channel through which magma rises during an  Seismic zone eruption  Cone  Large underground pool of molten rock and gases  Bedrock called magma  Magma chamber  It is caused by the eruption  Ash cloud  It is built up in layers  Solidified lava  Secondary cone-shaped formation around the  Secondary cone crater  Vent  Exit point  Truncated cone-shaped formation around the crater, built up by the accumulation of lava from previous eruptions  It is made up of particles that fall around the volcano.  Layer of solid rock beneath the surface of the Earth

8 The Earth’s internal dynamics

24. Complete the flow chart.

6. The Wilson cycle

25. Work with your partner to fill in the missing information.