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Transcript
Earth’s Structure Earth’s Structure Structure of the Earth Chemical Composition The chemical makeup of Earth's materials Crust – average depth 30 km outermost layer Low density rock Silicate minerals (silicate and oxygen) Mantle – largest volume 30 m -2900 km high density Iron and magnesium silicate Core – 2900 km – 6370 km large mass, higher density metal, iron and nickel Physical Composition How rocks respond to increased temperature and pressure at depth Based on physical properties, Earth is composed of five layers Inner Core Outer Core Mesosphere Asthenosphere Lithosphere Lithosphere Earth’s cool, rigid, outermost layer Extends from surface to 100 km Includes the crust plus the topmost portion of the mantle Brittle – it will fracture when force is applied to it SUBDIVIDED oceanic crust continental crust Oceanic Crust Composed of Igneous rock basalt Dark colored Relatively high density ~3.0 g/cm3 Average thickness ~ 8 km (5 miles) Originates as molten magma beneath the Earth’s crust Continental Crust Composed of lower density, lighter colored igneous rock granite Density ~ 2.7 g/cm3 Originates beneath the surface as molten magma. Average thickness is about 35 km (22 miles) May reach a maximum of 60 km (37 miles) Highest mountain ranges Asthenosphere Weak ball Plastic - will flow when a gradual force is applied From 100 km to 700 km Base of upper mantle Hot enough to partially melt portions of most rocks Mesosphere Middle ball Extends to 2885 km Middle to lower mantle Deforms plastically Rigid due to increased pressure Outer Core Liquid Capable of flowing Inner Core Rigid Does not flow due to increased pressure Composition of the Earth Video The compostion of the Earth