The geochemistry and petrogenesis of the Ni-Cu-PGE Shakespeare deposit, Ontario, Canada

Abstract

The Shakespeare intrusion, which hosts the Shakespeare Ni-Cu-PGE sulfide deposit, is part of the 2.2 Ga Nipissing Gabbro magmatic event, a large mafic-ultramafic suite located in the southern Superior and Southern Province. The Shakespeare intrusion intrudes the 2.2-2.45 Ga Huronian Supergroup and is located in the northern part of the Southern Province, only a few km from the Archean – Proterozoic unconformity which separates the Superior Province from the Southern Province and is adjacent to the ~ 2450 Ma East Bull Lake and Agnew Lake intrusions. The Shakespeare deposit is the largest Ni-Cu-PGE deposit in the Nipissing Large Igneous Province (LIP). Field mapping and drilling have provided a detailed stratigraphic understanding of the deposit and provide the framework for geochemical models of sulfide segregation related to assimilation. The U-enriched rocks that interacted with the intrusion during ascent through the crust provide an excellent opportunity to gauge the role of assimilation during the formation of the Shakespeare deposit while providing further evidence that crustal sulfur is necessary in order to generate economic concentrations of magmatic sulfides.