Jesse Koroscil's Honours Thesis Abstract

New exposure of the Paleoproterozoic Animikie Group at the Terry Fox Monument northeast of Thunder Bay reveals several thrust faults that cut through the Gunflint Formation, Sudbury Impact layer and the overlying Rove Formation.  This discover has implications for the timing of thrust-fault deformation in the area north of Lake Superior.  Previously, thrust-fault deformation in the Gunflint Formation was interpreted to be associated with the Penokean orogeny.  New evidence collected at the Terry Fox Monument suggests thrust faulting may be related to late Penokean deformation or possibly a younger orogeny.  Thrust faulting at this location is observed cutting the impact layer and overlying Rove Formation meaning that this deformation may be too young to be attributed to the Penokean orogeny.

The thrust faults at the Terry Fox Monument rock cut are mainly expressed as small discrete bedding plane faults with few kinematic indicators or piercing points to quantify the displacement.  The faults are most easily identified where they cut through stratigraphy, once identified faults can be traced laterally along the outcrop.  Similar to other units present, thrust faults within the impact layer are identified by slickenlines or slickenfibres on fault plane surfaces.  The faults can be traced along strike until they are either covered by overburden or cut by a prominent normal fault which displaces all units in the hangingwall down to the south several meters.