Potential-field modelling of the prospective Chibougamau area (NE Abitibi subprovince, Quebec), using geological, geophysical and petrophysical constraints

This contribution focusses on obtaining a better understanding of the subsurface geology of the Chibougamau area, in the NE of the Abitibi greenstone belt (Superior craton), using geophysical data collected along a 128 km long traverse with a rough SW-NE orientation. We have constructed two-dimensional (2D) models of the study area that are consistent with newly collected gravity data and high-resolution magnetic datasets. The initial models were constrained at depth by an interpretation of a new seismic section and at surface by the bedrock geology and known geometry of lithological units. The attributes of the model were constrained using petrophysical measurements so that the final model is compatible with all available geological and geophysical data. The potential-field data modelling resolved the geometry of plutons and magnetic bodies which are transparent on seismic sections. The new model is consistent with the known structural geology, such as open folding, and provides an improvement in estimating the size, shape, and depth of the Barlow and Chibougamau plutons. The Chibougamau pluton is known to be associated with Cu-Au magmatic-hydrothermal mineralisation and, as the volume and geometry of intrusive bodies is paramount to the exploration of such mineralisation, the modelling presented here provides a scientific foundation to exploration models focused on such mineralisation