Porphyry Cu-Au-Mo systems, especially those formed along continental active margins, are generally considered to have formed in contractional tectonic environments of crustal thickening, surface uplift and rapid exhumation (e.g., Sillitoe, 2010). The tectonic environment of porphyry systems formed in island arcs, such as those located within the Stikine terrane of northwestern BC, are not as well understood.