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Published byMerryl Ami McCoy Modified over 9 years ago
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Our Amazing Planet
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Engage Assignment Make a 3 slide power point on each of the three types of plate boundaries – Convergent boundaries – Divergent boundaries – Transform boundaries Include the following explanation of the type of boundary Picture of each type of boundary Crustal features that form at each type of boundary
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Planet Earth Earth’s Layers
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Crust Earth’s thin outermost layer. – Continental Crust (land) - thick low density rock (granite). – Oceanic Crust (sea floor) - thin dense rock (basalt)
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Mantle Earth’s thickest layer made of dense iron-rich super heated soft rock. Convection currents occur in the Mantle.
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Convection Currents in the Mantle Main cause of plate tectonics Hot magma rises and cooler magma sinks (Just like boiling water)
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Core Earth’s innermost layer made of hot, dense iron and nickel. – Outer core - Liquid – Inner core - Solid
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Lithosphere Earth’s outermost layer Includes the crust and solid upper part of the mantle. Divided into huge pieces called “Tectonic Plates”. Moves around on top of the asthenosphere - very hot, soft layer of the mantel.
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Earth’s Tectonic Plates
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Continental Drift Theory – Theory that the Earth’s continents move over time – Proposed by Alfred Wegener in the early 1900’s – Evidence of Continental Drift: Continents fit together Similar fossils records Similar rocks and minerals Similar rock formations (mountains) Similar climatic conditions – Glaciations
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Continents Fit Together
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South America and Africa
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Similar Fossil Records
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Other Evidence - Glaciations Evidence of the movement of massive ice sheets (glaciers).
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Sea Floor Spreading Occurs where tectonic plates spread apart at Mid Ocean Ridges Magma rises from inside the Earth creating new sea floor. New sea floor pushes the existing sea floor out explaining why continents move. – Evidence that supports the theory of Continental Drift.
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Sea Floor Spreading
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Mid-Atlantic Ridge
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Convection Currents in the Mantle
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Tectonic Plate Boundaries
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Convergent Boundaries Tectonic plates collide - Forms trenches, mountains, and subduction zones CTMS – Convergent – trenches – mountains - subduction
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Convergent Boundaries Subduction Zones Creates trenches in the ocean and mountains and volcanoes on land
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Divergent Boundaries Tectonic plates move apart Causes earthquakes Forms Mid Ocean Ridges and Rift Valleys East African Rift Mid-Atlantic Ridge
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Transform Boundaries Tectonic plates slide past each Forms Fault lines and causes earthquakes San Andreas Fault in California
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Volcanoes and Earthquakes Most Occur at Tectonic Plate Boundaries
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Hot Spots Areas in the middle of tectonic plates where magma inside the Earth rises through the crust and forms volcanoes.
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Hawaii Islands
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Super Volcanoes Yellowstone National park 3 overlapping calderas underground is believed to have formed from a hot spot creating Yellowstone’s “Super Volcano”
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Yellowstone
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