QUEST FOR HIDDEN MINERAL RESOURCES: A GEOCHEMICAL APPROACH

The quest for new mineral resources is taking explorationists to areas covered by deep overburden, such as Tully Township in the southwestern Abitibi Greenstone Belt in northeastern Ontario. This 100 km² area lies just north of the world famous Porcupine Gold Camp and is covered by deep Pleistocene overburden (>30m) deposited by glacial Lake Barlow-Ojibway. Extensive exploration has located six gold-bearing prospects despite there being only one outcrop in the township. The success of future exploration efforts could be greatly improved if a geochemical vector toward gold mineralization can be identified.

Lithogeochemical analyses will be performed on 185 wallrock samples collected from drill core preserved in the Ministry of Northern Development and Mines core library. The analyses will include major and minor elements by Induced Coupled Plasma Optical Emmission Spectrometer, as well as loss on ignition (LOI) and CO₂ analysis. Additionally, carbonate from 212 vein samples will be analyzed to determine their d¹⁸O and d¹²C contents.

There are two distinct areas with high LOI values located in the southeast and upper midwest areas of the township. There are also CO₂ values in these areas. The percent of total CO₂ that is attributable to LOI can be calculated using the formula ((CO₂/LOI)*100). This calculation indicates that there are high concentrations of wallrock-hosted carbonates in the upper midwest area of the township. The close association of CO₂-rich fluids with gold mineralization in the Porcupine Gold Camp bodes well for this area. Interpretation of wholerock lithogeochemistry and stable isotope data that is being gathered will be presented.