1.1 Earth's Interior

  • Define: 

    • Examines the materials composing earth and the processes that operate beneath and on the surface 

  • Understanding earth's history 

    • Fossils and rocks give us information about the earth's past conditions 

    • Modern processes help us understand ancient environments 

  • Early earth 

    • Dense elements (Fe, Ni) to center, less dense elements to surface (differentiation) 

    • Establishes discrete layers 

  • Earth's interior 

    • Three concentric layers 

      • Outer most layer: crust 

        • Crust: solid, protective outer layer 

          • Continental crust: thicl (25-40 miles), contains less dense elements (Si, O, Al, K), Granite 

          • Oceanic crust: thin (5 miles), contains dense elements (Fe, Mg), basalt 

            • Continental vs. Oceanic 

              • Oceanic is more dense 

              • Continental is older and thicker 

          • Rocks within the crust are hotter and weaker with depth 

      • Middle layer: mantle 

        • Mantle:  

          • Lower mantle: solid and strong 

            • Called Asthenosphere: soft and weak layer 

              • Temp/pressures near top cause some melting = magma 

          • Upper mantle: solid 

            • Called lithosphere: when combined with crust 

              • Lithosphere is detached from the asthenosphere; it floats 

      • Inner layer: core 

        • Core: very hot despite the continuous heat loss for 4.5 billion years ago 

          • Inner core is solid. Outer core is liquid 

          • Movement of iron creates Earth's magnetic field 

            • Both inner and outer core are made of nickel and iron (very dense) 

        • Temperature, pressure and density increase with depth 

  • Evidence 

    • Earth's radius 

      • 4,000 miles; 4,000 miles to the center of the earth 

      • Deepest mines: 2.5 miles 

      • Deepest drilled holes: 8 miles (this is 0.2% of the distance) 

    • KEY: behavior of energy waves that are released from earthquakes/explosions as they passthrough the Earth 

      • Refraction: when earthquake energy waves change based off of the earth's layers 

  • Laws in science 

    • Mathematical ties to science that can explain science 

      • Newton's law of motion, gravity