The Silidor Deposit, Rouyn-Noranda District, Abitibi Belt; geology, structural evolution, and paleostress modeling of an Au quartz vein-type deposit in an Archean trondhjemite

The Silidor deposit is a representative example of a pluton-hosted lode gold deposit; the Silidor mine contains 2.95 Mt, grading 5.1 g/t Au. The mineralized zone is 900 m long, with a vertical extent of 900 m and an average thickness of 3.5 m. Its alteration envelope is a red hematite-altered trondhjemite. The mineralized zone comprises vein quartz (white, grey and smoky), beige mineralized trondhjemite, and green carbonate-sericite-fuchsite breccia, which resulted from shearing and metasomatism of an early diorite dyke. A quantitative microtectonic study on a tonalite sill in the mine area was carried out to reconstruct the deformation before, during and after the mineralizing events. The Silidor deposit is the result of several vein-filling events which occurred during evolution from strike-slip faulting to reverse faulting regimes.