Abstract
The Colomac mine has produced >15,000kg of gold from Archaean subvolcanic rocks of the Slave Province of the Canadian Shield. Two deposit types with distinct styles of gold ore mineralisation exist: (1) shallow, low-grade, high-tonnage deposits with primarily sulphide-hosted gold; and (2) deeper, localised, high-grade deposits comprising native gold–quartz veins. Both deposit types formed from H2O–CO2–NaCl fluids at temperatures of 250–375°C and pressures of 1–2kbar and appear to be a part of a single mineralising system in which the mechanism of gold deposition dictated the style of mineralisation. Colomac provides an opportunity to address the basic causes of gold accumulation in the earth's crust by documenting processes leading to the formation of large, low-grade deposits (fluid–wall rock reaction) versus localised, high-grade deposits (fluid unmixing) in greenstone belts.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
