Into the Moving Earth (Quiz 1.1)

• Layers of the Earth: Crust > Mantle > Outer Core > Inner Core
• Lithosphere - crust and upper mantle that make up the tectonic plates
• Asthenosphere -consists of lower mantle and outer core which is responsible for convection.
• 2 types of crust

  • Continental
  • Oceanic
• • Continental - light granitic rock and aluminum silicates
  • Thicker 
  • Rarely destroyed 
  • 29% of earth’s surface
• Oceanic - dense basaltic rock and magnesium silicates

  • Denser
  • Constantly destroyed
  • 71% of earth’s surface
• Mantle

  • Semisolid, rocky, thick, and very hot layer of the earth made up of ferro-magnesium silicate rocks
• Upper Mantle - part of lithosphere
• Lower Mantle - part of asthenosphere
• Core

  • Innermost layer of the earth, beneath the mantle and made up of molten iron and nickel
• Outer Core

  • The only liquid layer
  • Responsible for the magnetic field
• Inner Core 

  • Innermost layer of mostly solid iron
  • Responsible for gravity
• Conrad - continental and oceanic crust
• Mohorovicic - crust and upper mantle
• Repiti - upper and lower mantle
• Gutenburg - lower mantle and outer core
• Lehmann - outer and inner core
• Kola Superdeep Borehole - 11 kms deep
• Earthquakes 

  • Scientists analyze the seismic waves created by earthquakes, volcanic eruptions, etc.
  • uses seismographs and seismometers to detect and record.
• • Body Waves - travels through the inner layers of the earth
  • P waves and S waves
• Surface Waves - travels only through the surface of the earth

  • Rayleigh and Love waves
• Types of Seismic waves

  • Body
  • Surface
• Types of Body waves

  • P waves
  • S waves
• Types of surface waves

  • Rayleigh
  • Love
• P waves (Primary) first to be felt on the earth’s surface
• Compressional waves - waves that travel back and forth
• S waves (Secondary) - 60-70% slower than P waves
• Transverse waves - waves that travel in an up and down motion
• Rayleigh waves - move in elliptical motion (like actual ocean waves)
• Love waves - move parallel to the earth’s surface and perpendicular to the direction of propagation
• Fastest seismic wave - P wave

  Slowest seismic wave - Love wave

  Most destructive wave - Love wave
• Pangaea - a single supercontinent
• Pan meaning all

  Gaia meaning Earth
• Pangaea is surrounded by vast ocean “Panthalassa”
• Continental Drift

  • Proposed by Alfred Wegener
  • Pangaea broke to 2 super subcontinents:
  • Laurasia and Gondwana
  • It was proposed in 1912
• Evidences of Continental Drift

  • Fit coastline of Africa and South America
  • Similarities of plant and animal fossils in South America, African, and Antarctica
  • Sequences of rock layers on opposite sides of atlantic ocean.
• Seafloor Spreading

  • Proposed by Harry Hess in 1960’s
  • Coined that the seafloor - not the continents are moving
  • Continents are only carried by the seafloor
• Plate Tectonics Theory

  • Incorporation of Continental Drift and Seafloor Spreading
  • Lithosphere is composed of slab and solid rocks known as plates
  • Movement produced by Convection Current
• 7 Main Plates of the World

  • Eurasian
  • Australian
  • Pacific
  • North American
  • South American
  • African
  • Antarctic
• 7 Continents

  • Asia
  • Africa
  • North America
  • South America
  • Europe
  • Australia
  • Antarctica