Using mineral chemistry to detect the location of concealed porphyry deposits - an example from Resolution, Arizona

Porphyry-related mineral districts can host many major ore deposits of diverse styles and metal associations, including porphyry, epithermal and skarn deposits. In these deposits, hydrothermal alteration is typically zoned, and alteration zoning has long been an important tool used in their exploration (Fig. 1). However, the various mineral assemblages and textures that characterize each alteration zone are also present within barren hydrothermal systems, and in some cases may also be produced by non-mineralizing processes such as regional metamorphism. Discriminating mineralized and barren systems, being able to locate well-mineralized hydrothermal centers, and recognizing the distal footprints of mineralization continue to be great challenges to explorers. In this abstract, we demonstrate how the combination of epidote and chlorite chemistry can be used to successfully detect the location of a porphyry deposit, using the Resolution porphyry Cu-Mo deposit as a case study. The results presented in this paper are derived from a blind site test submitted to AMIRA International project P765A by Rio Tinto Exploration (RTX).