Copper occurrences in the Heathcote Greenstone belt

Abstract

"Copper has been known in the Heathcote Greenstone Belt since the 1880s when fencing contractors discovered the Mount Camel Copper Show. The Copper Show had native copper, cuprite and copper carbonates that were exposed in costeans in 1906. The first systematic exploration occurred when Western Mining Corporation Ltd explored for copper between 1967 and 1972, conducting extensive soil and induced polarization surveying. The Western Mining Corporation Ltd soil grid shows anomalous copper values along the entire northern segment of the Heathcote Greenstone Belt, but the mineralisation was regarded as essentially pyrite and pyrrhotite with minor chalcopyrite. The Toolleen Group explored the Mount Camel Copper Show area as an aside from their exploration for gold in the greenstone belt between 1984 and 1990, after discovering numerous gossans. Gossans have also been discovered near Mount Ida and near Cornella. Geological understanding of the Heathcote Greenstone Belt has progressed since the last exploration for copper. The belt is thought to consist of two genetically different parts, in three segments. The northern and southern segments are ophiolite sequences with a simple structural style. In the aeromagnetic data these are seen as extensive (tens of kilometres) linear magnetic and nonmagnetic bands due to banded iron formation, cherts and jasper. The central segment, host to the Mount Camel Copper Show and a small copper occurrence west of Mount Ida, is thought to be of island-arc origin, and has a complicated structure, with faulted slices of Ordovician sediments within the Cambrian volcanics. Induced polarization anomalies are attributed to these Ordovician graphitic shales. The central segment has discrete, high magnetic responses, inferring that the magnetic units have short strike length, unlike the magnetic units in the northern segment. The geophysical surveys to date do not appear to have detected any mineralisation. Induced polarization and spontaneous potential anomalies are probably due to Ordovician graphitic shales approximately 20 m west of the Mount Camel Copper Show."