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From core to ore: emplacement dynamics of nickel sulphide systems

Ivrea Zone, Italy

Unlike most mineral resources, which are generally concentrated in a wide range of crustal reservoirs, nickel and platinum are concentrated either in the core or in the mantle of our planet. In punctuated events throughout Earth history, large cataclysmic magmatic events have had the capacity to transport and concentrate these metals from their deep source to upper crustal levels. With this Fellowship, I will unravel the complex emplacement mechanism of these magmas and constrain the role that volatiles such as water and carbon dioxide played in the emplacement and metal endowment of these systems.  

I will build new understanding on the emplacement dynamics of mantle-derived Ni-Cu-PGE sulphide systems through investigation of key natural examples in the Ivrea-Verbano Zone (IVZ) of northwest Italy. This domain of deeply exhumed lower crust and mantle rocks hosts the most comprehensive and coherent suite known of deep-level Ni-Cu-PGE sulphide bearing mafic/ultramafic intrusions, providing a unique opportunity to resolve the dynamic emplacement and evolution of such magmatic ore bodies.

This research has three principle aims:

1. Documenting the relationship between size and geometry of the intrusions and structural architecture of the host rocks into which they were emplaced;
2. Establishing the role that volatiles (e.g. H2O, CO2, etc.) played in the emplacement of the intrusions and the attainment of sulphide saturation - a key process in the formation of Ni-Cu-PGE sulphide deposits, and;
3. Constraining the physical mechanisms and controls on emplacement and localisation of the intrusion-hosted ore systems.

I will undertake a multi-faceted research strategy comprising three principle modules addressing the respective core aims of the project:

1. A field component combining detailed mapping, structural analysis and selected sampling of the IVZ intrusions and their host rocks;
2. A focused laboratory study of the stable isotope geochemistry of hydromagmatic phases (i.e. H, B, Li, O, Ne, Ar) and sulphides (i.e. S, Fe, Ni, and Cu) within the ore systems; and
3. An integrated program of numerical simulation and analogue modelling to evaluate physical models of emplacement processes and fluid dynamics, complimented by geophysical ground truthing.