Temporal constraints on gold mineralisation at the world-class Jundee deposit: Insights into the episodic nature of orogenic gold mineralisation in the Neoarchean Yilgarn Craton

Abstract

The proposed genetic model for orogenic gold deposits hosted in Archean cratons worldwide has long assumed a single, late-orogenic mineralisation event. Recent geochronological developments and their application to gold deposits, however, have challenged this conventional view and indicate that gold endowment in several world-class Archean systems developed over distinct mineralisation stages. Here, we present U-Pb geochronological data from igneous zircons extracted from pre-, syn-, and post-mineralisation intrusions from the world-class Jundee gold deposit in the Yilgarn Craton of Western Australia. The crystallisation age obtained for a syn-mineralisation lamprophyre indicates that gold mineralisation occurred at ca. 2670 Ma, which is ca. 30 Ma older than the previously proposed gold episode (ca. 2640 – 2630 Ma) for the region. When integrated with fast-emerging, high-quality geochronological data from other major gold deposits across the Yilgarn Craton, our results highlight the occurrence of an early, syn-orogenic mineralisation event between ca. 2675 – 2655 Ma, which pre-dated the ca. 2640 – 2630 Ma late-orogenic gold event identified across the Kalgoorlie Terrane. This older gold mineralisation event was concurrent with the onset of the Neoarchean Kalgoorlie Orogeny in the Yilgarn Craton, which also coincided with a peak in mantle-derived magmatism (e.g., lamprophyres and sanukitoids). The younger gold event was coeval with intra-crustal granite plutonism and peak metamorphic conditions that occurred during the late- to post-collisional evolution of the Yilgarn Craton at ca. 2640 – 2630 Ma. Comparison between the Yilgarn Craton in Western Australia and the Superior Craton in Canada demonstrates that both record multiple gold events that occurred during protracted orogenesis. This study underscores the importance of tectonic processes in shaping the episodic nature of gold mineralisation in these ancient cratons.