Ore genesis with igneous rocks. The world's major copper deposits are formed within the granitic porphyry copper style. Copper is enriched by processes during crystallisation of the granite and forms as chalcopyrite — a sulfide mineral, which is carried up with the granite. Sometimes granites erupt to surface as volcanoes, and copper mineralisation forms during this phase when the granite and volcanic rocks cool via hydrothermal circulation. Sedimentary copper forms within ocean basins in sedimentary rocks. Generally this forms by brine from deeply buried sediments discharging into the deep sea, and precipitating copper and often lead and zinc sulfides directly onto the
Chalcopyrite chalcopyrite has no solid solution series with any other sulfide minerals. There is limited substitution of Zn with Cu despite chalcopyrite having the same crystal structure as sphalerite. Minor amounts of elements such as Ag, Au, Cd, Co, Ni, Pb, Sn, and Zn can be measured (at part per million levels), likely substituting for Cu and Fe. Selenium, Bi, Te, and As may substitute for sulfur in minor amounts. Chalcopyrite is present with many ore-bearing environments via a variety of ore forming processes. Chalcopyrite is present in volcanogenic massive sulfide ore deposits and sedimentary exhalative deposits, formed by deposition of