Possible Tectonic a.nd Metallogenic Relationships Between Porphyry Copper and Massive Sulphide Deposits
Pyritic massive sulphide deposits lie conformably above submarine volcanic rocks, and beneath siliceous and manganiferous iron formations. The massive bodies are often zoned, with a barren pyritic top grading downward into pyrite with sphalerite, and occasionally galena, and a chalcopyrite-rich base. They are frequently brecciated, like the lavas beneath them, which contain pyrite and chalcopyrite as coatings on joints and fractures and as dispersed grains. The lavas also exhibit propylitic, argillic a-qd silicic alteration. These sulphide deposits appear to have formed on sea bottom from fluids escaping through the lavas during periods of exhalative and sometimes explosive volcanism. The process may be comparable to the present deposition of base metals from hot brines in the Red Sea.
brine, chalcopyrite, porphyry copper, Red Sea, University of Western Ontario, Deposits, Porphyry copper deposit, Porphyry copper deposits, pyrite, sulphide, Sulphides