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. © McGraw-Hill Education Biology and Geology 4. Unit 8. The Earth’s internal dynamics 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, _____________________________________________________________________________ © McGraw-Hill Education Biology and Geology 4. Unit 8. The Earth’s internal dynamics 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. © McGraw-Hill Education Biology and Geology 4. Unit 8. The Earth’s internal dynamics 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). © McGraw-Hill Education Biology and Geology 4. Unit 8. The Earth’s internal dynamics 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. __ © McGraw-Hill Education Biology and Geology 4. Unit 8. The Earth’s internal dynamics 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 © McGraw-Hill Education Biology and Geology 4. Unit 8. The Earth’s internal dynamics 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. © McGraw-Hill Education Biology and Geology 4. Unit 8. The Earth’s internal dynamics 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. © McGraw-Hill Education Biology and Geology 4. Unit 8. The Earth’s internal dynamics 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 © McGraw-Hill Education Biology and Geology 4. Unit 8. The Earth’s internal dynamics 8 The Earth’s internal dynamics 5.