Article ID Journal Published Year Pages File Type
9529273 Chemical Geology 2005 19 Pages PDF
Abstract
The new properties are used to calculate chalcopyrite solubilities under similar conditions of two magmatic-hydrothermal copper deposits for which copper concentrations have been measured in individual fluid inclusions: the Starra iron oxide-Au-Cu deposit, Australia; and the Bajo de la Alumbrera porphyry copper deposit, Argentina. In both cases our calculated copper concentrations are consistent with the measured values in inclusions that trapped pre-mineralising and mineralising fluids. More generally, calculated chalcopyrite solubility at different temperature, pressure, pH, chloride concentrations and oxidation states indicates that hypersaline, neutral-weak acidic, and intermediate-reduced brines can transport thousands of ppm copper at 400 °C and above, raising interesting questions about the interpretation and importance of liquid-vapour partitioning of copper. Although cooling is probably the major factor responsible for copper deposition in magmatic-hydrothermal environments, fluid mixing, boiling and fluid-water interaction may be more important in other geological environments, e.g., iron-oxide-copper-gold and epithermal ore deposits.
Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Geochemistry and Petrology
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