The geology and metamorphism of the Nairne pyritic formation, a sedimentary sulfide deposit in South Australia

The Nairne pyritic formation at the base of the regionally metamorphosed Kanmantoo group (considered Cambrian in age) in the eastern Mount Lofty ranges, South Australia, consists of two main sulfide-bearing members composed of thin- bedded quartz-rich sediments in which pyrite predominates in coarsergrained rocks and pyrrhotite in finer-grained more micaceous rocks, separated by 1,500 feet of sulfide-free graywackes and quartzites. Graded bedding and other features of the pyritic rocks suggest an origin involving chemical precipitation of hydrous iron sulfides in a shallow-water environment followed by redeposition in deep waters by turbidity currents.

This record provided courtesy of AGI/GeoRef.