KINEMATIC FABRICS NEAR MINE CENTRE, ONTARIO: EVIDENCE FOR A MODIFIED TRANSPRESSION MODEL.
Czeck, D. M. and Hudleston, P. J., Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Dr. SE, Minneapolis, MN 55455
The boundary between the Quetico and Wabigoon subprovinces within the Archean Superior Province is characterized by ductily deformed metamorphic rocks from Greenschist- Amphibolite facies which have been amalgamated through continental accretion processes. The working kinematic model to describe this area is transpression (Hudleston et. al, 1988) which explains the dominant flattening fabric in the vertical plane and the noncoaxial strain observations in the horizontal plane. Theoretical work on transpression has shown that the long axis of the strain ellipsoid, and thus the mineral lineation measurements, are necessarily either vertical or horizontal. Structural field work in this study has shown that the lineations along the Wabigoon-Quetico boundary vary between 0-90° within the foliation plane. Therefore, a modification to the three-dimensional transpression model is necessary to adequately describe the deformation process.
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