creating boundaries at which the plates converge‚ diverge or move past each other. These plates are either continental or oceanic and are powered by convection currents‚ which is the circular movement of magma that comes from within the mantle. These currents are powered by the core‚ which heats the magma‚ causing it to rise‚ cool and fall back down. This circular motion causes the plates‚ which float on the mantle‚ to move. In 1912‚ Alfred Wegener‚ a German meteorologist‚ was the first man to state
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igneous rocks‚ sedimentary rocks and metamorphic rocks. I. The first type is igneous rocks (from the Greek word for fire) which are formed from molten rock (magma) and lava. A. Formation 1.coming up of magma through cracks 2. forming a layer on surface or filling other cracks 3. cooling forming a very hard igneous rock 4. magma on the surface of the earth‚ lava _ basalt B. Importance 1. geologically important - showing characteristics of a specific tectonic environment 2
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by color‚ streak‚ luster‚ hardness‚ cleavage‚ and fracture. Minerals form by magma erupting and forming lava then cooling. They can also form by evaporation of water containing dissolved ions. Silicates are the most common group of minerals found in the earth’s crust. The structure of minerals are orderly. They form crystalline. A crystalline has flat faces and smooth surfaces. Igneous rocks are formed from magma. If they are intrusive (plutonic)‚ they have large crystals and cooled slowly
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FULL SET OF NOTES ON TECHTONICS 2012 AQA GEOGRAPHY FULL SET OF NOTES ON TECHTONICS 2012 AQA GEOGRAPHY TECHTONICS | TOPICS | UNDERSTOOD/COVERED? | PLATE MOVEMENT | | SEISMICITY | | VULCANICITY | | These notes were copied from an AQA textbook. They contain EVERYTHING you need to know for the exam for the tectonics section. You WILL however‚ need to use your own case studies as these are not included. You will need 2 case studies for volcanoes‚ and 2 case studies for earthquakes
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causing vulcanicity. In the destructive plate boundary‚ magma currents beneath earth crust converge‚ dragging two plates together while the heavier plate sinks and being subducted under another plate‚ the subducted zone will then be melt back to magma again. Pressure accumulates while the subduction of the heavier plate is occurring‚ crack will develop on both plates near the boundary allowing magma to seep through them onto the earth surface. Magma that rose through the cracks may soon be cooled down
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A Divergent plate boundary is a tectonic boundary where two plates are moving away from each other and new crust is forming from magma that rises to the Earth’s surface between the two plates. The middle of the Red Sea and the mid-ocean ridge (running the length of the Atlantic Ocean) are divergent plate boundaries. Divergent boundaries are characterized by a rift in the surface of the earth along the midocean ridges that exist in all of the major ocean basins. The ridges are composed of volcanic
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1. Wegner’s hypothesis of continental drift using the observation that the earth’s surfaces are continually changing and other evidence was that the continents had once been joined‚ and over time had drifted apart but he couldn’t explain the mechanism behind it. 2. Evidence gathered by Ewing‚ Tharp and Hess that lead to the theory of plate tectonics was: ⦁ In the early 1950s Ewing‚ with the help of Marie Tharp‚ a cartographer‚ mapped the seafloor using available echo profiles‚ the resulting mapped
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Plate Tectonics Designed to meet South Carolina Department of Education 2005 Science Academic Standards Table of Contents Plate Tectonics: The Beginning (slides 3 and 4) Layers of the Earth (slides 5 and 6) Standard 8-3.1 What are Tectonic Plates- movement? (slides 7 and 8) Standard 8-3.6 Tectonic Plate boundaries (slides 9-21) 1. Convergent boundary Ocean-continent (slide 10) Continent-continent (slide 11) Oceanic-oceanic (slide 12) Volcanism (slide 13) 2. Divergent boundary Sea-floor
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Earthquake‚ shaking of the Earth’s surface caused by rapid movement of the Earth’s rocky outer layer. Earthquakes occur when energy stored within the Earth‚ usually in the form of strain in rocks‚ suddenly releases. This energy is transmitted to the surface of the Earth by earthquake waves. The destruction an earthquake causes depends on its magnitude and duration‚ or the amount of shaking that occurs. A structure’s design and the materials used in its construction also affect the amount of damage
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two crusts are moving towards each other‚ the denser crust(eg. the oceanic crust)is subducted under the less dense one (eg. the continental crust). The oceanic crust is heated by friction and contact with the upper mantel‚ which melts it into magma. As magma is less dense than the continental crust above‚ thus it will rise to the surface to form volcanoes. For example‚ the Pacific plat is subducting beneath the Eurasian plate at the Japan Trench. The long arc of islands that make up
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