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

Abstract

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.

Analysis and Interpretation of Regional Gravity Data in the Swayze greenstone belt of the Superior Province, Canada

“…"'"'' were considered relative to an average upper crustal density in the Superior Province of 2.72 g/cm 3 , based on previous studies (e.g. Nitescu et al, 2006;Maleki et al, 2021). Three gravity models were obtained with the Oasis montaj GM-SYS tool along the profiles shown in Figures 2 and 3.…”

“…Peschler et al (2004) presented different models of the Abitibi greenstone belt where the plutons have depth extents between 1 to 4 km and tabular shapes, whereas the greenstones bodies form keels with depths extents up to 8 to 10 km. Maleki et al (2021) presented various detailed models of the Chibougamau area in the Abitibi greenstone belt, based on gravity, magnetic and seismic data, where the mafic metavolcanic rocks have a vertical extent of 3 to 7 km and the plutons have depth extents to 9 km. In general terms, the vertical extents of the geological units observed in the models of this project fit the range found for the Archean greenstone belts in the Superior Province.…”