Earth Science

• Perovskite


  A silicate rock
• Mesosphere


  • Much stronger than the asthenosphere
  • Flows with more resistance
  • Strength increases with depth due to immense pressure from overlying layers
• Outer core


  The only mechanical layer made of liquid - melted Fe-Ni alloy
• The liquid nature of the outer core is due to extremely high temperatures (more than 3000°C) that melt Fe, Ni, and all other elements
• The flow of liquid metals in the outer core is responsible for the Earth's magnetic field
• Lehmann discontinuity


  The outer-inner core boundary
• Inner core


  A solid ball of mostly Fe despite the extreme temperature, due to the overwhelming pressure
• Temperatures in the inner core are similar to the temperatures of the surface of the Sun - around more than 5400°C
• Mineral


  • Naturally-occurring
  • Inorganic
  • Homogeneous solid
  • Has definite chemical composition
  • Has ordered crystalline structure
• Properties of minerals

  • Color
  • Luster
  • Crystal habit or shape
  • Streak
  • Hardness
  • Cleavage or fracture
  • Density or specific gravity
  • Tenacity
  • Diaphaneity
  • Magnetism
  • Effervescence
  • Odor and taste
• Thousands of different minerals have been identified and named, but only a few are abundant on the Earth's crust (rock-forming minerals)
• Out of all the elements, only 8 make up most rock-forming minerals
• Silicates


  The most common mineral group, using oxygen and silicon as their "building blocks"
• Non-silicate mineral groups


  • Native elements
  • Carbonates
  • Oxides
  • Sulfates
  • Phosphates
• Igneous rocks


  Formed when molten material cools and solidifies
• Intrusive igneous rocks


  Form below the Earth's surface
• Extrusive igneous rocks


  Form on the Earth's surface
• Intrusive vs extrusive igneous rocks

  Intrusive have bigger/coarser mineral grains, extrusive have smaller/finer grains
• Komatiite


  A very rare type of extrusive igneous rock that forms when extremely hot lava cools rapidly, common during the Archean eon
• Other extrusive igneous rocks

  • Obsidian
  • Bombs
  • Blocks
  • Volcanic ash
• Sedimentary rocks


  Formed from loose sediments that have been eroded, buried and compacted
• Types of sedimentary rocks

  • Clastic sedimentary rocks
  • Chemical sedimentary rocks
  • Biochemical or organic sedimentary rocks
• Metamorphic rocks


  Formed when a rock is subjected to chemical or physical processes that alter its composition, mineralogy, and/or texture
• Foliated metamorphic rocks


  Have a planar arrangement of mineral grains, result of deformation
• Non-foliated metamorphic rocks


  Develop in environments with minimal deformation, other factors like chemically-active fluids play a larger role
• Rocks continually undergo changes that alter their characteristics, ultimately changing them into different rocks (rock cycle)
• Erosion


  A geological process where earth materials are weathered and transported
• Deposition


  The process of adding eroded earth materials to an environment or landform
• Types of depositional environments

  • Terrestrial environments
  • Transitional environments
  • Marine environments
• Terrestrial depositional environments

  • Fluvial
  • Eolian
  • Alluvial
  • Glacial
  • Lacustrine
• Terrestrial landforms and waterforms

  • Mountains
  • Hills
  • Plains
  • Valleys
  • Plateaus
  • Deserts
  • Glacial environments
  • Rivers
• Transitional depositional environments

  • Beach
  • Deltaic
  • Tidal flat
  • Lagoonal
• Transitional landforms and waterforms

  • Deltas
  • Wetlands
  • Swamps
  • Marshes
• Marine depositional environments


  • Shallow marine/reefal
  • Continental shelf
  • Continental slope
  • Deep marine
• Tidal flat


  Low-lying areas affected by tides
• Lagoonal


  A small body of water closed off from a larger body of water (the ocean)
• Associated landforms and waterforms

  • Deltas
  • Wetlands
  • Swamps
  • Marshes
• Deltas


  Areas at the end of the mouth of a river where freshwater mixes with seawater
• Wetlands


  Areas near rivers or coastlines where soils are saturated or submerged in water
• Swamps


  Wetlands where trees dominate plant life