Polyorogenic reworking of ore-controlling shear zones at the South Range of the Sudbury impact structure: a telltale story from in situ U-Pb titanite geochronology

The post-impact orogenic evolution of the world-class Ni-Cu-PGE Sudbury mining camp in Ontario remains poorly understood. New temporal constraints from ore-controlling, epidote-amphibolite facies shear zones in the heavily mineralised Creighton Mine (Sudbury, South Range) illuminate the complex orogenic history of the Sudbury structure. In situ U-Pb dating of shear-hosted titanite grains by LA-ICP-MS reveals new evidence for crustal-scale reworking during the Yavapai (ca. 1.77 – 1.7 Ga), Mazatzalian - Labradorian (1.7 – 1.6 Ga), and Chieflakian - Pinwarian (1.5 – 1.4 Ga) accretionary events. The new age data show that the effects of the Penokean orogeny (1.9 – 1.8 Ga) on the structural architecture of the Sudbury structure have been overestimated. At a regional scale, the new titanite age populations corroborate that the Southern Province of the Canadian Shield document the same tectonothermal episodes that are recorded along orogenic strike within the accretionary provinces of the southwestern United States.