Minerals and earths crust

• The lithosphere is made up of the crust and upper mantle layer

  5-100km thick
• The lithosphere provides

  • physical resources like fossil, fuels and ores
  • biochemical cycles by recycling C, N and P
  • soil which sustains plant life
• A mineral is a chemical compound with a specific chemical formula, crystal structure and properties
• A rock is a mixture of naturally occurring aggregate and minerals
• An ore is a rock with enough of a mineral deposit to make it economically worth extracting
• Over exploitation of resources can cause

  • exhaustion of reserves
  • increased production of harmful waste
  • land degradation
  • lower quality of life for later generations
• Metamorphic rock is metamorphic, igneous or sedimentary rock that has undergone pressure and temperature to change its composition
• Igneous rock is formed from cooled lava and magma
• Sedimentary rock is formed by the cement action of sediment and minerals
• Intrusive igneous rock cools and solidifies slowly under the earths surface allowing for large crystals to form.

  Example is granite
• Extrusive igneous rocks cools and solidifies quicker and above ground resulting in small crystals.

  example is pumice
• A batholith is a large underground mass of solidified molten magma
• Types of sedimentation

  • Proterozoic marine sediments
  • alluvial deposits
  • evaporates
  • secondary enrichment
  • biological sediments
• Proterozoic marine sediments are formed dissolved iron compounds become oxidised by the oxygen release by photosynthesis producing insoluble iron deposits. Occurred 2.5-1.8 billion years ago.
• Alluvial deposits are formed by materials that where carried and separated by water. This included gold, diamonds and clay
• Evaporites form when a bay of ancient sea becomes isolated and the water evaporates leaving crystal minerals behind.
• Secondary enrichment is when economically important metals form minerals that are carried in solution and are deposited as the oxidation state changes.
• Biological sediments are created when organisms use materials dissolved in the air and water to build up their tissue and when they die there build up of organic matters form minerals and rocks.
• Stock includes all the materials in the lithosphere. It includes the materials that which can be exploited and will never be exploited.
• A resource is a material that can be exploited technically and economically now or in the future.
• A reserve is a portion of a resource that is accessible to be exploited because of current technology
• Ore purity is the % of an ore found in a material. The purer the ore is the cheaper it is to extract a particular quantity.
• Cut off ore grade is the lowest purity of ore that can be mined economically at current market prices.
• Environmental impacts of mineral extraction

  • landtake
  • land clearance
  • habitat loss
  • loss aesthetics
  • pollution (noise, dust)
  • decreased biodiversity
  • soil stability
  • traffic congestion
  • toxic leachate
• viability of a deposit depends on

  • close to transport roads
  • protect site
  • market value
  • shape of deposit
• future ore extraction techniques

  • Phyto mining
  • bio leaching
  • polymer absorption
  • Deepsea sediments
• satellite surveys detects infrared reemitted from earths surface as different types of rocks reemit different levels of infrared
• magnetometry detects the different magnetism of rocks. more magnetic rocks usually contain metals like iron
• gravimetry uses grace satellites which detects different densities and mass of deposits. difference in distance of grace satellites correlates to different densities of deposits.
• seismic surveys uses sound waves by controlled explosions or seismic vibrations. echo's gives information of density depth and shape