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.

First Page Preview

First page PDF preview
You do not currently have access to this article.