Application of Petrology & Geology to the Interpretation of Geophysical Data in Defining Economic Porphyry-Related Cu-Au Mineralisation Along the Ekuti Range, Morobe Province, PNG

Abstract

Detailed petrologic and petrophysic data obtained from surface rock chip and diamond core of the Mt Leahy Tenement, Ekuti Range porphyry copper-gold exploration project area, Morobe Province, Papua New Guinea have been applied to interpretations of geologic setting and hydrothermal environment of mineralisation, and interpretations of airborne magnetic field data in defining a causative intrusion framework for mineralisation. Petrologic data confirm and refine a model of magmatic hydrothermal fluid sources for structurally confined mesothermal to epithermal style Cu, Au, Mo, Ag, Pb, Zn and Bi mineralisation within eroded composite granodiorite, quartz monzodiorite and diorite/andesite intrusion centres and hornfelsed metasedimentary rock, with potential for delineation of “disseminated” porphyry and hornfels styles of mineralisation. The application of petrophysic data, derived from petrology, to the interpretation of airborne magnetic field data defines three intrusion centres within the Leahy tenement: a northern and relatively deeply eroded Otibanda-Weke/Waikanda composite intrusion zone, and higher-level Kopekio and Ekoato intrusion domains, the latter with greater potential for discovery of low-grade high-tonnage style copper-gold mineralisation.