Timing of gold mineralisation in the Pine Creek orogen, Northern Territory, Australia: its significance to the thermal-aureole gold model

摘要

For much of the last two decades, gold occurrences in the Pine Creek orogen frequently have been cited as type-examples of high-temperature contact-metamorphic or thermal-aureole deposits associated with granitoid mag-matism. Recent fieldwork, coupled with radioisotopic dating of hydrothermal phosphates using SHRIMP, indicates that the age of gold mineralisation is typically younger than the youngest phase of granitoid intrusion, and certainly postdates the effects of contact metamorphism. This evidence suggests that these deposits are late-stage orogenic gold deposits, formed in the contact-aureole of HHP granitoids, but after peak contact-metamorphism.