Geologic overview of the Carlin Trend gold deposits and descriptions of recent deep discoveries.

More than 40 deposits have been delineated and over 25 000 000 oz Au mined since disseminated gold was first discovered in carbonate rocks in Nevada in 1961. Gold is hosted by rocks varying from Ordovician to Lower Mississippian in age, comprising a shelf carbonate and siliciclastic sequence, a mainly eugeosynclinal siliciclastic sequence and an overlap sequence; in addition, up to 15% of mineralisation is in Cretaceous and Tertiary dykes and a granodiorite stock. The NNW alignment of the deposits results from a combination of features in a zone of crustal weakness and sustained high heat flow. Characteristic alteration features are carbonate dissolution, argillic alteration of silicates, silicification and Au-enriched sulphidisation of reactive Fe. Deep deposits found in the last ten years include Storm (Rossi), Goldbug-Rodeo, Screamer, Deep Star, Turf, West Leeville, Hardie Footwall, Mike and Rain Underground.
More than 40 deposits have been delineated and over 25 000 000 oz Au mined since disseminated gold was first discovered in carbonate rocks in Nevada in 1961. Gold is hosted by rocks varying from Ordovician to Lower Mississippian in age, comprising a shelf carbonate and siliciclastic sequence, a mainly eugeosynclinal siliciclastic sequence and an overlap sequence; in addition, up to 15% of mineralisation is in Cretaceous and Tertiary dykes and a granodiorite stock. The NNW alignment of the deposits results from a combination of features in a zone of crustal weakness and sustained high heat flow. Characteristic alteration features are carbonate dissolution, argillic alteration of silicates, silicification and Au-enriched sulphidisation of reactive Fe. Deep deposits found in the last ten years include Storm (Rossi), Goldbug-Rodeo, Screamer, Deep Star, Turf, West Leeville, Hardie Footwall, Mike and Rain Underground.