formation processes

• Hydrothermal Deposition

  • the accumulation of minerals in fractures and cavities resulting from the circulation of hot waters in the Earth's crust
  • a batholith is formed when the minerals seperate and deposited making later exploitation
  • ores deposited are tin, copper, lead, sliver, gold, arsenic
• many geological processes make exploitation of minerals possible

  • normally involves the separation of mixtures of mineral to produce localised concentrations of mineral that are suffiently pure for economic extraction
• metamorphic processes-

  • igneous processes and tectonic movement of crust plates can change rock with the high temp and pressure
  • ie high temps change limestone to marble
  • extrame pressure changes mudstone to slate
• igneous processes

  • rocks and minerals created by the cooling and hardening of magma
• sedimentary processes

  • causes minerals to settle and build up to produce layers of deposited sediment
• Proterozoic marine sediments-

  • They were formed when dissolved iron compounds became oxidised by the oxygen released by photosynthesis, producing insoluble iron oxide deposits.
  • oldest deposits
• Alluvial deposits

  • Alluvial processes involve materials that were carried and separated by flowing water.
  • includes- gold, diamonds, tin ore, gravel, sand, clay,
• Evaporites

  • If a bay of an ancient sea became isolated, then the water may have evaporated leaving crystallised minerals such as halite
• Biological sediments

  • Biological processes are those where living organisms form mineral deposits. These processes often concentrate minerals that can be deposited in sedimentary rocks.