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Tectonostratigraphic controls on the localisation of Archaean komatiite-hosted nickel-sulfide deposits and camps in the Yilgarn Craton

Yilgarn Craton, Australia

This is one of the largest nickel project initiatives ever undertaken in Australia. The project looks into the lithospheric framework in which komatiites were emplaced after forming at depth in the mantle. Therefore, the study investigates how to predict the localisation of mineralised komatiite clusters or camps in different terranes. 

Since the rock record of the Early Earth is fragmental, preserved Archaean nickel, gold and iron mineral systems represent unique windows into the primordial stages of our planet. The shape and evolution of Archaean lithospheric blocks are reflected in the spatial distribution of high-temperature komatiite lavas and associated nickel-sulphide mineralisation. These formed in geodynamic settings where mantle-derived magmas were emplaced without significant differentiation and heat loss, most likely along major lithospheric discontinuities such as craton margins. The processes responsible for crustal amalgamation and widespread intra-cratonic deformation are reflected in the nature and distribution of major gold-bearing lithospheric structures. Conversely, the evolution of near-surface paleo-environments is reflected in the distribution of iron-formations with variable sedimentary facies and iron content. Archaean mineral systems provide snapshots of the rapidly changing geodynamic and ecological evolution of the Early Earth.