Supergene Oxidation of Copper Deposits: Zoning and Distribution of Copper Oxide Minerals

Abstract

ABSTRACT Copper oxides represent an attractive exploration target because even low-grade prospects have the potential to produce low-cost copper in an environmentally friendly fashion. Derived from liypogene and/or supergene sulfides, copper oxides comprise a series of distinct assemblages that characterize a variable pH. oxidizing geochemical environment known as “the oxide zone.” Development of oxide copper minerals is a function of source-rock and host-rock mineralogy, pyrite and other (copper) sulfide abundance and distribution, fracture density and distribution, phreatic and/or vadose zone occurrence and stability, and maturity of the weathering profile The paragenesis оf copper oxide mineral formation reflects local, dynamic changes in supergene solution composition attributable to reaction between host-rock mineral components and dissolved species Especially important are the concentrations of because mineral assemblages, even those that are metastable. represent the geochemical environment in which they formed, identification and mapping of copper oxides is useful in interpreting the geochemical history of an oxide zone. Furthermore, practical application of oxide zone geochemistry is significant in the recognition and solution of problems associated with weathering-engendered metals oxidation and transport from mine wastes.