EVSC 2800 Study Guide - Midterm Guide: Batholith, Porphyritic, Copper Sulfide
12 May 2016
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Consumption in the us is about 1. 7 million tons of metal per year. We produce about 1. 2 million tons per year. Most consumption of copper is related to its electrical conductivity. The average content of copper in the continental crust is 0. 0058% by weight. An ore is a concentrated occurrence of a desirable element, present at concentrations high enough to be exploitable economically: malachite is hydrated copper carbonate, chalcopyrite is a mixed copper and iron sulfide, chalcocite is copper sulfide. Hydrothermal fluids: much cooler than magma, typically around 300 degrees c, circulating through the country rock, they fluids can dissolve and carry metals. Country rock is what encloses an ore deposit: chalcopyrite and azurite are localized along a fracture in the country rock. Disseminated copper deposits are associated with felsic to intermediate intrusive igneous rocks with a porphyritic texture: usually have large mineral grains in a relatively finer-grained matrix.
