An Archean sequence of rocks is exposed along Highway 527, approximately 90 kilometers north of Thunder Bay. This sequence consists of metasedimentary and metavolcanic rocks which have been affected by lower greenschist facies metamorphism.
Structural elements in the area are S-surface and folds. S-surface are designated S0, S1, S2, and S3, while folds are designated F1, F2, and F3.
Cleavage-bedding relationships delineate the hinge lines of F2 folds. Younging information projected onto the axial planar cleavage (S2) of F2 folds, results in reversals in the structural facing directions. These reversals indicate that the cleavage developed in previously deformed rocks.
The overprinting of structural elements indicates that three deformational events (D1, D2, D3) can be defined.
D1 produced nearly vertical and, in part, inverted F1 folds. D2 produced a set of F2 folds which resulted in refolding of the F1 structures. D3 produced kink bands and crenulations that resulted in folding of the F1 and F2 structures.