Structural relations between the polydeformed Flin Flon arc assemblage andMissi Group sedimentary rocks, Flin Flon area, Manitoba and Saskatchewan

The structure of the Flin Flon area (Manitoba and Saskatchewan) has been ex amined through mapping of mesoscopic and macroscopic structures in both the ca. 1900 Ma Flin Flon arc assemblage volcanic basement and the unconformab ly overlying (or fault juxtaposed) ca. 1845 Ma Missi Group continental sedi mentary cover sequence. The Flin Flon and Callinan volcanogenic massive sul phide orebodies occur within the basalt-dominated basement. The contact bet ween the basement and the cover rocks was investigated in detail during thi s study. The cover sequence records three principal fold- and foliation-for ming events. All deformation observed within the cover sequence is correlat ive with deformation observed within the volcanic basement. Significant low -angle overlap of basement on cover is attributed to development of a D-1 n orth-verging nappe and subsequent thrust displacement on the overturned bas ement-cover contact. North-verging D-1 structures provide evidence for a di stinct post-Missi Group deformation event that preceded regional, southwest ward D-2 thrusting at peak metamorphic conditions across the southeastern T rans-Hudson Orogen. D-2 deformation produced closed to tight, west-verging overturned folds with a well-developed axial planar cleavage and a pervasiv e extension lineation. D-3 deformation generated open folds of the S-2 and a weakly to moderately developed spaced axial planar S-3 cleavage. D-3 and D-4 deformations produced sinistral-oblique, brittle-ductile reverse faults that offset all older features.