Variations in nickel tenor in magmatic sulfides deformed during the 1.7-1.6 Ga Mazatzal/Labradorian Orogeny, Thayer Lindsley mine, Sudbury, Canada (Ontario)

The Thayer Lindsley mine hosts contact- and footwall-style magmatic Fe-Ni-Cu-PGE sulfide ore in the South Range of the 1.85 Ga Sudbury Igneous Complex (SIC). Some ore zones at the mine are overprinted by lower amphibolite facies shear zones that offset the contact between the SIC and underlying footwall rocks of the Paleoproterozoic Southern Province. The main goals of this study are to (1) characterize the geometry and kinematic history of shear zones at Thayer Lindsley mine, (2) present the first U-Pb titanite and 40Ar/39Ar radio-isotopic ages for shear zones cutting through the SIC, and (3) examine the effects of deformation on pre-existing contact-style ore.; The shear zones contain two populations of titanite grains. Older anhedral brown titanite grains yield a mean 207Pb/206Pb Penokean age of 1815 +/- 15 Ma. This first population of titanite grains is mantled by younger, syn-tectonic, colourless titanite, which yield a mean 207Pb/206Pb age of 1658 +/- 68 Ma.; Strongly sheared contact-style sulfide ore at the mine is characterized by low Ni tenor (wt. % Ni in 100% sulfide) and high Pt and Pd tenors relative to undeformed contact-style sulfide ore, and by extensive replacement of pentlandite by pyrrhotite and pyrrhotite by pyrite and marcasite. (Abstract shortened by UMI.)...