Stratiform platinum-group element mineralization in the layered Northern Ultramafic Center of the Lac des Iles Intrusive Complex, Ontario, Canada

Detailed stratigraphic variation of modal rock type, modal minerals, selected PGE, base metals and trace elements throughout the CUA-6 which hosts the Lower Middle Interval from selected drill holes NL12-100. The rapid increase of Pd, Pt and Au abundance halfway through the cycle, accompanied with the increase of S and Cu abundances (which reflect sulfide mineralization) and the decrease of enstatite content clinopyroxene suggests that the mechanism of initial sulfur saturation and, by inference, the collection of precious and base metals is related with fractional crystallization. The abrupt increase of sulfide mineralization in the hybrid unit, just below the level at which CUB magma was emplaced, coinciding with the reversal (decrease) in enstatite content of clinopyroxene implies that the introduction of CUB magma also prompted the formation of an immiscible sulfide liquid and the collection of precious and base metals.226