Two phases of ductile deformation, followed by thrusting and extension, affected the Ketza River Mine area. D1 produced large scale E-W trending folds (F1) with upright axial planes, and a pronounced axial planar foliation (S1). Large scale F2 folds have E-W axial trends coincident with those of F1, and moderately NNE-dipping axial planes and axial planar foliation (S2). D2 also produced small-scale, SSW-verging folding of S1 along E-W to NW trending axes.
Shallowly SSW-dipping thrust fault surfaces, and regional analogies suggest NE-directed thrusting (D3). An extensional event (D4) coincided with the timing of mineralization. Normal displacement along the S-dipping Peel Fault resulted in the separation of the map area into two stratigraphic domains:: predominantly unit 1a argillites exposed in the northern domain, and predominantly unit 1d limestones exposed on the southern domain. Subsequent to the development of the Peel Fault, a series of NNW trending listric and planar normal faults separated the map area into four structural domains:: 1) western half-graben; 2) central horst; 3) eastern graben; and 4) eastern planar high-angle fault blocks. Axial-planar extensional veins developed along drag folds associated with graben-forming faults are intimately associated with manto-style orebodies. Several orebodies extend from listric normal faults in the preferentially mineralized limestone facies, suggesting that D4 faults were primary conduits for mineralizing fluids. There is no regional equivalent of D4. D4 may represent brittle response to the emplacement of a pluton.
The last deformation event (D5) produced a reverse fault that conceals the eastern portion of the Peel Fault (D4). D5 was a local, post-mineralization event that produced little dismemberment of the orebodies.
