Economic Geology

Economic Geology

1. Making Money from Geology

   • Metals (ores)
   • Water Supplies
   • Waste Disposal
   • Excavation work
   • Volcano Tourism
   • Earthquake Prediction
   • Minerals
   • Coal

2. Finding Subterranean Resources

   • Geochemical Analysis
     • To find an economic deposit of a mineral
     • Collect water from a range of sites on a stream network
       • Analyse samples
         • If there is a deposit, water that has 'permeated' through it will have picked up parts of it (dissolved)
           • Plot results
             • Higher concentration will be downstream of the ore body
     • If a high concentration meets a low concentration stream, the concentration will be in between the two
     • Background levels of minerals in nature are approx. 10-20ppm
     • If water goes through a mineral vein, concentration will rise to over 500ppmn places
       • ppm=parts per million
   • Borehole Drilling
     • Expensive
     • Gives best evidence of a resource being present
     • Confirms what a seismic survey will suggest is there
     • Must analyse the core the borehole produces
   • Seismic Survey
     • Exploration for oil
     • Ship tows a source of seismic waves (air gun)
       • Travels along a transect (line)
         • At certain times it generates a shock wave (seismic wave)
           • They travel through the floor and rocks and get reflected when there is a change of rock type (/density)
             • Travel back to receivers (towed by boat)
               • Generates an image of rock structure below
                 • Image analysed by a geophysicist
                   • Decides whether to recommend a borehole
   • Magnetic Survey
     • Helicopters fly over an area
       • With equipment that detects anomalies in the earths magnetism
     • Processing software highlights areas with unusual magnetic fields
       • e.g metallic minerals, igneous bodies etc

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