Chemical mineralogy of supergene copper deposits of the Cloncurry district, north west Queensland

Abstract

The research described in this thesis has led to an understanding of the geochemical conditions controlling the formation, paragenesis and distribution of oxide zoner copper species in the Eastern Fold Belt of the Mt. Isa Inlier. This area is also known as the Cloncurry Complex. The regional geology and genesis of the copper deposits is reviewed and the deposits of particular interest to the study are described. Oxidation of pyrite and chalcopyrite by oxygen-bearing groundwater and the sources and mechanisms by which anions are carried by groundwater to reaction sites to form secondary copper species are discussed. Physical and chemical conditions control the development of particular species. Equilibrium phase diagrams have been constructed to represent stability fields. An explanation for the relative abundance and spatial distribution of the basic copper phosphates is provided. Stability field data supported by observations made on deposits in the Cloncurry district and elsewhere provides a basis for assessing the paragenesis and distribution of secondary copper species in this and similar environments. This is discussed and illustrated using the Great Australia mine as a model.

Date of Award	1998
Original language	English