Geology

Lake Cowal is located on the Lachlan Fold belt which has historically been the source of many mineral discoveries of local, regional and national importance. The Cowal ore body is hosted in an Ordovician-aged volcanoclastic sequence informally referred to as the Lake Cowal volcanic complex. The volcanic sequence is overlain by alluvial sediments of the Jemalong Plains, depending on the underlying paleaeo topography. Gold mineralisation primarily occurs in dilational quartz-carbonate-sulfide and carbonate+/-quartz-sulfide veins. The highest gold grades have been recorded in a series of pods that are vertically elongated and trending north south. These pods are disrupted by west-northwest trending faults near the centre of the mineralisation zone. Sulfide mineralisation in the veins consists of pyrite, sphalerite, chalcopyrite, pyrrhotite and galena. Adularia is a common mineral.