There are several major copper-bearing deposit styles, including various porphyry, iron-ore copper gold (IOCG), Sedimentary exhalative (SedEx) and volcanogenic massive sulphide (VMS) deposits. Each of these copper deposit styles are characterised by distinct mineral alteration zones, which can be detected by the high resolution HyMap spectrometer.
For most of these deposits, copper is mineralisation is sourced from either the magmatic intrusions and/or remobilised from surrounding country rock via large sub-surface hydrothermal convection systems. Generally, sub-surface magmatic intrusions are characterised by acidic and oxidised fluids whilst regional hydrothermal systems are generally characterised by alkaline and reduced fluids. If these hydrothermal fluids are subjected to a change in either temperature, pressure or redox then the copper will be deposited, along with much larger associated alteration mineralogy haloes.
HyMap data is well suited to rapidly mapping many important propylitic-potassic minerals including chlorite, epidote, actinolite, biotite and carbonates that are associated with various copper deposits. Accurate and precise mapping of surface mineralogy provides an indirect measure of paleo redox and temperature at time of mineral crystallisation.