The Geosphere

What is the GEOSPHERE? All solid parts of Earth – Rocks, soils, minerals, sediments, magma The Grand Canyon, AZ

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Layers of the Earth 1.Crust- O, Si, Al 2.Mantle- O, Si, Mg, Fe 3.Core- Fe, Ni Geologists classify Earth’s layers two ways: chemically and physically Chemical – by composition Physical- by structure Chemical Layers of the Earth

Physical Layers of the Earth Lithosphere – Crust and upper mantle combined – Broken in chunks called tectonic plates – Oceanic plates are thinner and denser than continental plates Asthenosphere -Layer of Jello-like magma in the mantle -Tectonic plates move due to convection currents in the asthenosphere

Physical Layers, cont. Mesosphere – The rest of the mantle; molten rock Outer Core – Liquid metal – Surrounds inner core Inner Core – Densest layer – Solid metal

Remember… LAMOI, The physical trainer

YzY YzY earth layer song

Theory of Plate Tectonics Lithosphere (upper mantle and crust) is divided into pieces called tectonic plates. These plates glide across the underlying asthenosphere like ice drifts across a pond. Continents are located on tectonic plates and move around with them

Plate Boundaries The area where two plates meet is called a plate boundary. Most earthquakes and volcanoes occur at or near plate boundaries Three main types of plate boundaries: 1.Divergent- separating 2.Convergent- colliding 3.Transform- scraping past

Earthquakes Worldwide Tectonic Plates Active Volcanoes

Transform Boundaries 2 plates slide past each other This sliding is not smooth. Plates lock and build up tension. After too much tension builds, the plates “snap” and move against each. Causes earthquakes

Divergent Boundaries When two plates separate Most common on ocean floor Creates Mid-Atlantic Ridge which is visible on land in Iceland

Divergence Forms New Ocean Floor

Convergent Boundaries Three Main Types: 1.Continental & Oceanic- causes deep ocean trench and land volcanoes Ex: Andes Mountains 2. Oceanic & Oceanic- causes deep ocean trench and island arc (chain of volcanic mountains) Ex: Mariana islands and Mariana trench 3. Continental & Continental- causes large land mountain ranges Ex: Himalayan Mountains

Subduction Zone Continental + Oceanic Crust

Subduction Zone Oceanic + Oceanic Crust

Subduction Zone Oceanic + Oceanic Crust (another view)

Continental + Continental Crust

Some videos for your viewing pleasure… Plate Movement: dmE&feature=endscreen&NR=1 dmE&feature=endscreen&NR=1 San Andreas Fault: PTLmg0ZCw&feature=endscreen PTLmg0ZCw&feature=endscreen