EARTH STRUCTURE

• Earth's structure


  The Earth is made up of 3 main layers: Crust, Mantle, Core
• Crust


  • Thin and solid outermost layer of earth, located above the mantle
  • 5 - 100 km thick
  • Thinnest layer of the Earth
  • Less than 1% of Earth's mass
• Types of crust


  • Continental crust
  • Oceanic crust
• Continental crust


  • Thicker than oceanic crust
  • Composed of oxygen, silicon, aluminum, iron, calcium, and magnesium
  • Mostly composed of different types of granites
  • Geologists refer to it as "sial"
• Oceanic crust


  • Thinner but denser than continental crust
  • Almost twice as much iron, calcium, and magnesium
  • Mostly composed of different types of basalts
  • Geologists refer to it as "sima"
• Mantle


  • Layer of rock between the crust and the core
  • Much thicker and contains most of the Earth's mass (roughly 2/3 or 67%)
  • Has more magnesium and less aluminum and silicon than the crust
  • More dense than the crust
• Core


  • Central part of the Earth below the mantle
  • Mostly made of iron and nickel, with almost no oxygen, silicon, aluminum, or magnesium
  • Makes up roughly 1/3 (33%) of the Earth's mass
  • More dense than the crust
• Lithosphere


  The outermost, solid/rigid layer made up of the crust and the rigid upper part of the mantle, divided into tectonic plates
• Asthenosphere


  The soft layer of the mantle on which the tectonic plates move, solid rock that flows very slowly
• Mesosphere


  Comprising the inner part of the mantle, a region of very hot solid rock
• Outer core


  Liquid layer of the Earth's core, between the mantle and inner core
• Inner core


  Solid, dense center of the Earth
• Continental drift


  Large-scale horizontal movements of continents relative to one another and to the ocean basins during one or more episodes of geologic time
• Plate tectonics


  Pieces of the lithosphere that move around on top of the asthenosphere, causing the Earth's crust to be divided into major plates that collide, pull apart, or scrape against each other
• Plate tectonics


  • Each type of plate interaction causes a characteristic set of Earth structures or "tectonic" features
• How scientists know the Earth's structure


  1. Seismic waves traveling through the Earth

  2. Waves travel at different speeds due to density in the layers

  3. Waves travel faster through solids than liquids

  4. Seismographs measure the waves

  5. This information can track thickness and density of each physical layer
• Compound

  • composed of two or more elements
• Sial

  • silicate and aluminum
  • abundant minerals in continental crust
• Sima

  • silicate and magnesium
  • most abundant in oceanic crust
• Basalts

  • sima rocks
• Lithosphere

  • the outermost, solid/rigid layer
• Lithosphere

  • includes the brittle upper portion of the mantle and the crust
• Asthenosphere

  • temperature and pressure of the asthenosphere are so high that rocks soften and partly melt, becoming semi-molten
• Mesosphere

  • hotter than asthenosphere
• Mesosphere

  • pressure is too high for liquid rock to form
• Continental Drift

  • precursor to the development of the theory of plate tectonics
• Continental Drift

  • Alfred Wegener introduced the theory that all continents were once united in supercontinent, Pangaea, then drifted apart to form different continents
• Divergent Plate Boundary

  • two plates move away from each other
• Convergent Plate Boundary

  • plates move towards each other and collide
• Transform Plate Boundary

  • two tectonic plates slide past each other
  • San Andreas Fault
• Tectonic

  • deformation of the crust as a consequence of plate interaction
• Major Plates:

  • African Plate
  • Antarctic Plate
  • Eurasian Plate
  • Indo-Australian Plate
  • North American Plate
  • Pacific Plate
  • South American Plate
• Minor Plates:

  • Indian Plate
  • Nazca Plate
  • Juan de Fuca Plate
• Plate Tectonics

  • theory that explains how Earth's outer layer, or lithosphere, is made up of several large pieces called plates.
• Name the plates:

  
• Give the 7 continents

  1. Africa
  2. Antarctica
  3. Asia
  4. Europe
  5. North America
  6. South America
  7. Australia