Minerals and Rocks

Rocks §

• A rock is a naturally formed consolidated material composed of grains of one or more minerals
• Earth’s surface is extremely diverse in terms of rock makeup and types etc
• Made up of one or more minerals/pieces of other rocks
• They form through different geologic processes
• Three types of rocks, Igneous, Sedimentary, Metamorphic, all defined by the process that creates them
• The rock cycle shows how rocks are created and destroyed
  • Plate tectonics play an important role in the rock cycle
  • Sediments are transported, buried and lithified, forming sedimentary rocks
  • Sedimentary and igneous rocks are altered forming metamorphic rocks
  • Earth’s internal heat and pressure melts material, producing igneous rocks
  • 
  • Plate Tectonics and the rock cycle
  • Uplift (surface exposure) happens due to tectonics. Mostly happens at convergent boundaries
  • Space for sediments is often created by tectonic motions, at divergent boundaries
  • Metamorphism often occurs at convergent boundaries. It can alter any type of rock

Igneous Rocks §

Sedimentary Rocks §

Metamorphic Rocks §

Minerals §

• minerals are naturally occurring, inorganic, crystalline solids
  • they have specific chemical composition and distinctive physical properties
• Rocks are composed of one or more minerals
• Minerals have 5 characteristics
  • Solid
  • Naturally ocurring
  • Inorganic
  • Ordered internal structure (crystalline)
    • Orderly arrangement of atoms in a repeating pattern
    • The internal structure influences the external form
  • Specific chemical composition
• About 4,000 minerals have been found so far
• Major mineral groups
  • Silicates (SiO)
    • Make up most of our crust so very important
    • These minerals are made up of Silica Tetrahedra. A silica atom surrounded by four Oxygen atoms
  • Carbonates (CaCO)
  • Halides (F, Br, Cl, I)
  • Oxides (O + metal)
  • Sulfides (S + metal)
  • Sulfates (S + O)
  • Native minerals (single elements)
• Key Minerals are Quartz and Feldspar (both abundant at the surface) and Olivine and Pyroxene (both abundant in mantle)

Atoms, Elements, and Isotopes §

• Chemical elements make up matter
  • Atoms: nucleus (protons and neutrons) and electrons
• Atomic Number
  • Number of protons (= # of electrons)
    • Determines the element
• Atomic mass number
  • Number of protons + neutrons
• Isotopes
  • Same element, different numbers of neutrons
  • Some isotopes are stable, some are unstable
    • Some unstable ones decay to a more stable one
• Making a mineral involves the bonding of atoms
• The type of bonding can affect a minerals strength and qualities (e.g. covalent vs ionic bonds)