* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Plate Tectonics and Associated Hazards
Geomorphology wikipedia , lookup
Provenance (geology) wikipedia , lookup
Post-glacial rebound wikipedia , lookup
Age of the Earth wikipedia , lookup
History of geology wikipedia , lookup
Composition of Mars wikipedia , lookup
History of Earth wikipedia , lookup
Algoman orogeny wikipedia , lookup
Geochemistry wikipedia , lookup
Future of Earth wikipedia , lookup
Mantle plume wikipedia , lookup
Plate Tectonics and Associated Hazards Unit 3 Section 1 : Plate Movement Structure of the Earth Tectonic Theory Plate Margins Hot Spots Section 2: Vulcanicity Volcanic Activity Major forms of Extrusive activity Minor forms of Extrusive activity Case study MEDC Case study LEDC Section 3 : Seismicity Earthquake Activity Tsunamis Case study MEDC Case study LEDC Brainstorm! What do you already know about Tectonics? Use the overview sheet as a starting point. Tectonics Section 1 : Plate Movement Structure of the Earth Key Questions: What is the structure of the Earth? What are the properties of the different layers? High temperatures near the core are believed to be responsible for the generation of convection currents. Approximately the size of Mars. Thinnest, coolest and least dense layer. Varies in thickness from 5 to 70 km. Most of the mantle (asthenosphere) acts like it is semimolten. Separated from the mantle by the Mohorovijic (Moho) discontinuity. Surrounded by semi-molten outer core. Temperature over 6000˚C. The most dense part of the planet. Made up of rocks rich in iron and nickel. The inner core is solid. Separated from the core by the Gutenburg discontinuity. Starts about 2900km down. Rocks are rich in silicon, oxygen, aluminium, potassium and sodium Temperatures near the core reach 5000˚C. Centre is 6350km down. Largely composed of silicate rocks rich in iron and magnesium. Upper mantle (close to the crust) is rigid and together with the crust forms the LITHOSPHERE. The Core • Approximately the size of Mars • Starts about 2900km down • Centre is 6350 km down • The most dense part of the planet • Made up of rocks rich in iron and nickel • Core temperature over 6000oC • Outer core is semi-molten/liquid (only part of the planet which is!) • Inner core is solid The Mantle • Separated from the core by the Gutenburg discontinuity • Largely composed of silicate rocks rich in iron and magnesium • Upper mantle (close to the crust) is rigid and together with the crust forms the lithosphere • Most of the mantle (asthenosphere) acts like it is semi-motlen. • Temperatures near the core reach 5000oC • High temperatures near the core are believed to be responsible for the generation of convection currents. The Crust • Thinnest, coolest and least dense layer. • Rocks are rich in silicon, oxygen, aluminium, potassium and sodium • Separated from the mantle by the Mohorovijic (Moho) discontinuity. • Varies in thickness from 5 to 70 km Some very important terms: Lithosphere: consists of the crust and the rigid upper section of the mantle, approximately 80-90km thick. Divided into seven large plates and a number of smaller ones. Asthenosphere: the semi-molten mass below the lithosphere on which the plates float and move. Beneath the asthenosphere is the rest of the mantle, which is completely solid. • What are the names for the two types of crust that form the lithosphere? • Use the text book to complete your own table like this one: Thickness Age Density Composition Continental crust Oceanic crust Think about a Ferrero Rocher This outer layer hold the liquid chocolate in, it’s the C. . . . . These nutty flakes float on the C. . . . Like P. . . . . . This liquid chocolate centre is like the M . . . . . Solid on the outside the central nut is just like the C . . . Evidence can be found lying on the Earth's surface. Occasionally rocks from deep inside the Earth's core are brought to the surface where they are collected and studied. How do we know all of this? Measurements of energy waves that pass through the Earth can be measured very accurately and at huge distances. They travel at different speeds through different materials. Scientists can translate this information into an accurate picture of the Earth's structure. Homework Start creating an electronic glossary for this unit – useful for revision. Key terms from today: Inner core Outer core Mantle Crust Lithosphere Asthenosphere Oceanic crust Continental crust Plenary squares. • Current seismic activity • http://www.iris.washington.edu/seismon/