Abstract
The Lamprecht and Felder deposits are roll-type deposits hosted by the Miocene Oakville Sandstone. Four distinct stages of FeS 2 mineral formation are recognized: (1) a generation of isotopically light (delta 34 S < -20 per mil) preore pyrite, (2) a generation of isotopically light (delta 34 S < -20 per mil) marcasite that formed mostly before, but also during ore deposition, (3) a postore generation of isotopically heavy pyrite (delta 34 S > 0 per mil), and (4) a yet later generation of marcasite with isotopically light sulfur close to the values of stages 1 and 2. Complex zone of mixing between saline brines migrating up the fault from depth and oxygenated meteoric water recharging at the outcrop. Bacterial activity.--Modified journal abstract.