The McEwan Lake fault: gravity evidence for a new structural element of the Kapuskasing zone
The Chapleau block, the largest uplifted crustal block within the Kapuskasing zone, continues, after sinistral offset of about 20 km, for a further 60 km to the southwest of Chapleau. This newly discovered extension, referred to as the Pineal Lake block, terminates to the west in a north-south-trending, west-verging thrust, named the McEwan Lake fault. New gravity data suggest that the fault has a vertical displacement of at least 5 km, a dip of about 25°E, and a length of at least 30 km. It is not known whether the fault crosscuts the Kapuskasing structure, in which case it may represent a younger thrusting event, or represents a southerly extension of the Saganash Lake fault that bounds the northwestern side of the Kapuskasing zone in the Chapleau area.