REGOLITH–LANDFORM MAPPING AS A VECTOR TO GOLD MINERALISATION UNDERCOVER: INSIGHTS FROM BALLARAT,

Staff from the Geological Survey of Victoria have recently completed a regolith mapping project in the Ballarat–Creswick area. The project was aimed to map and characterise the bedrock geochemistry of the major regolith–landform units and to determine if a major orogenic gold deposit, such as the Ballarat East goldfield, has a distinctive expression in the regolith. The mapping centred on a 10 × 28 km zone extending from the Ballarat East Goldfield in the south, north to Spring Hill, east of Creswick. This area was selected as a representative cross-section of the central Victorian goldfields, as it contains many elements of the landscape, a variety of differing surface and bedrock geological units and a centre of significant gold production. The results of the project are available as a report (Radojkovic & Bibby 2002), accompanying 1:50,000 scale map (Bibby & Radojkovic 2002) and fully attributed digital data. BALLARAT EAST GOLDFIELD About 47,000 kg of primary or orogenic gold was won from the Ballarat East goldfield, which extends from Black Hill south to near Buninyong. It came from a north-striking zone over 10 km long but only about 500 m wide that was worked down to less than 550 m. The goldfield is located along the subvertical eastern limb of the First Chance Anticline (Figure 1). Mineralisation is concentrated along stacked, moderately west