Structural interpretation of the Timmins Mining area, Ontario

Abstract

A reappraisal of Timmins structure indicates two periods of deformation, one involving N–S compression and a second characterized by a SW–NE couple that reoriented first-period folds and formed the Porcupine Syncline. Major faulting also resulted from this couple. Structure sections reveal that ultramafic rocks and felsic schists are stratigraphically distributed, suggesting that they are volcanic rather than intrusive. Problems concerning the origin, timing, and emplacement of gold and copper mineralization are considered in the context of the present structural interpretation.