Copper Porphyry

There are four major factors that often contribute to the formation of hydrothermal copper porphyry: 1) readily available mineralizing fluid solutions that dissolve and transport metals, 2) openings in rocks which allow permeable flow of hydrothermal fluids and the metals that they transport in solution, 3) available sites within the fractured rocks which allow for deposition of the minerals from solution, and 4) the requisite chemical reactions that contribute to that deposition (Bateman, 1967).
Before any of these factors come into play, however, there are tectonic processes that must happen to set the stage for development of copper porphyry deposits. Subducting tectonic settings are important for porphyry ore formation. While porphyritic deposits are found worldwide, it is important to note that the majority of these deposits are found near or at mantle plumes or subduction zones associated with back-arc volcanos. These areas may no longer be near an active mantle plume or subduction zones, but instead can be used to locate the ancient position of one.
Porphyry deposits are most often established in areas that are zones of low-angle subduction (Crooke and Hollings, 2005). Subduction
Hydrothermal solutions are transported with heat supplied by the magma and slowly lost as the solution moves through rocks (Bateman, 1967). With the proper temperatures (300-500̊) and pressures the copper enriched solution heated by the magma is driven up to shallower depths in the crust. The subducting tectonic activity helps drive this process with ground water acting on the copper solution from convective circulation creating a porphyry deposit. The ore solution must contain metal and sulfur in molecular species in concentrations sufficient enough to form a porphyry copper deposit (Bowen and Gunatilaka,