Exploration for IOCG deposits in Central Ontario

Mining Rocks! CIM Toronto 2005
Delio Tortosa,
Abstract Exploration by Nikos Explorations Ltd. in Central Ontario has focused on two properties north of Sault Ste. Marie. These properties, while exhibiting different styles of mineralization, share many characteristics of the IOCG class of deposits.

Copper-rich breccia style mineralization at the Island Copper property has been identified intermittently over an area of approximately 450 metres by 300 metres and occurs within a 1,000 metre by 400 metre envelope of hematite mineralization. The mineralization is hosted by a strongly albitized granitic breccia that occurs within brecciated gneiss of Archean age. Mineralization is structurally controlled, and the highest copper values occur at the intersection of fractures. A regional scale fault separating Archean gneiss from the Proterozoic Huronian Group occurs immediately south of the occurrence.

Mineralization at the Coppercorp property, mainly chalcocite with minor chalcopyrite, malachite, bornite and rare native copper, is predominantly hosted by Keewenawan age basalt. Vein and breccia-related mineralization with associated hematite, in the vicinity of the past-producing Coppercorp mine, exhibits strong structural control with subordinate lithological control. Calcite and epidote are the dominant alteration minerals with local K-feldspar enrichment. Elsewhere on the property, at deeper stratigraphic levels, copper mineralization is associated with a magnetite-actinolite-epidote assemblage.
Keywords: IOCG, Ontario, Alteration, Gold, Structure, Copper
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