What process produces Native copper ores in the earths crust, magmatic hydrothermal etc?
Native copper is a relatively rare mineral. It is almost always formed by secondary processes. The most common copper mineral is chalcopyrite (CuFeS2) though there are many other copper minerals. Native copper is often found in the oxide zone above or at the water table where chalcopyrite or some other copper sulphide becomes partially or fully oxidised. At depth, native copper can occur where there is chemical interaction between the reducing properties of graphite & chalcopyrite.
Copper is not created nor destroyed, so all of the copper that is in the Earth has been here for 4.5 billion years. All of the copper was formed during the Big Bang, and it is merely redistributed in the Earth by various processes related to plate tectonics including hydrothermal activity, plutonism, volcanism, and erosion. As Tashkent has correctly indicated, native copper is a rare mineral. Most copper occurs in various oxide and sulfide minerals including chalcopyrite, bornite, chalcocite, enargite etc. The only three native copper occurrences that come to mind are Keweenaw, Michigan; Corocoro, Bolivia; and White River, Yukon.
