Earth Structure + Composition

    Cards (32)

    • Earth's Structure
      • Core
      • Mantle
      • Lithosphere
      • Crust
    • The Geologic Cycle

      Rock Cycle—Igneous, Sedimentary, Metamorphic
    • Plate Tectonics
      • Sea-Floor Spreading
      • Subduction
      • Plate Boundaries
    • Earth congealed from a nebula, ~4.6 billion yrs
    • Gravity sorted the dust, gas, (icy) comets into concentric circles with the core being the heaviest and the crust being the lightest
    • Core
      • 1⁄6 of volume, of mass
      • Inner core is solid iron
      • Outer core is molten iron
      • Generates magnetic field that protects from solar wind/cosmic radiation
    • Lower & Upper Mantle

      • 80% earth's volume
      • Probably contain lots of water (in the crystalline structure)
      • Contains "hot spots" like Hawaii & other volcanic chains
    • Lithosphere
      Uppermost mantle + crust
    • Crust
      • Oceanic = 5 km
      • Continental = 20–60 km
    • Continental Crust
      • Granite
      • Crystalline
      • Low density (2.7 g/cm3)
    • Oceanic Crust
      • Basalt
      • Granular
      • High density (3.0 g/cm3)
    • Crust "floats" on denser layers below
    • Geologic Cycle
      1. Being formed by endogenic (internal) processes
      2. Worn down by exogenic (external) processes
    • Mineral
      Inorganic, non-living, natural compound with chemical formula & crystalline structure
    • Rock
      Assemblage of minerals, mass of a single mineral, or solid organic material
    • The Rock Cycle
      1. Igneous
      2. Sedimentary
      3. Metamorphic
    • Igneous Rocks

      • Solidify from cooling magma or lava
      • Magma is molten rock beneath the surface (intrusive)
      • Lava is molten rock at the surface (extrusive)
    • Intrusive Igneous Rocks

      • Slower cooling leads to larger crystals
    • Extrusive Igneous Rocks

      • Faster cooling leads to smaller crystals
    • Sedimentary Rocks

      Formed from the cementation, compaction, and hardening of sediments
    • Sedimentary Rocks

      • Sandstone
      • Shale
      • Limestone
      • Coal
    • Metamorphic Rocks

      Formed from the physical and chemical transformation of igneous or sedimentary rocks due to extreme pressure and heat
    • Metamorphic Rocks
      • Gneiss
      • Slate
      • Marble
      • Quartzite
    • Plate Tectonics
      • Changes in the configuration of the earth's crust due to internal forces
      • Upwelling of magma
      • Sea-floor spreading and subduction
      • Plate movements
    • Continental Drift Theory

      • Proposed by Alfred Wegener in the early 1900s
      • Suggested there was once a single "super continent" called Pangaea that floated on the oceanic crust
    • Evidence of Continental Drift
      • Continents fit together like a jigsaw puzzle
      • Fossils match across oceans
      • Rock types and mountain ranges match across oceans
      • Climate Evidence (Glacial Deposits)
    • Plate Boundaries
      • Spreading boundary - crust is being pulled apart
      • Converging boundary - one plate is subducted beneath another
      • Transform boundary - two plates glide adjacent to each other
    • Divergent Plate Boundary

      New crust being created, most associated with mid-ocean ridges
    • Convergent Plate Boundary

      Continental and oceanic crust collides, produces subduction zones, trenches, volcanoes (mountains), zones of compression and crustal loss
    • Transform Plate Boundary

      Plates slide past one another, rock of different types and ages may be found on opposite sides of the boundary
    • Hot Spots
      Areas on Earth that exist over a mantle plume, upwelling material from the mantle, occur beneath both continental and oceanic crust, some are fixed, others move
    • Plates move 1-10 centimeters per year (≈ rate of fingernail growth)