A 3D gravity data interpretation of the Matagami mining camp, Abitibi Subprovince, Superior Province, Québec, Canada. Application to VMS deposit exploration

Pierre Boszczuk (1) , Li Zhen Cheng (2) , Hanafi Hammouche (3) , Patrice Roy , Sylvain Lacroix (3) , Alain Cheilletz (1)

1 CRPG - Centre de Recherches Pétrographiques et Géochimiques
2 UQAT - Université du Québec en Abitibi-Témiscamingue
3 Bureau d'Exploration Géologique du Québec

Two inversions, unconstrained and constrained, of a gravity survey of the Matagami mining camp (Abitibi Archaean Subprovince, Canada) have been performed in order to identify the downward extension of a rhyolitic horizon hosting VMS-type base metals deposit and the morphologies of the major felsic plutons. A comparative study exhibits the similarities between measured and calculated densities from chemical compositions of the Matagami lithologies. This allows building an initial 3D geodensity model which integrates densities and available structural and geological surface mapping data. This model is integrated during the iteration process of the constrained inversion in the objective function. The resulting true density model and two derived cross-sections upgrade the 3D imaging of this area. Also, the model gives new insight for regional geological interpretation exposing possible shapes of the main geological units at depth and suggests the potential existence of deep fertile geological bodies.

Domaines: Planète et Univers [physics]

Pierre Boszczuk, Li Zhen Cheng, Hanafi Hammouche, Patrice Roy, Sylvain Lacroix, et al.. A 3D gravity data interpretation of the Matagami mining camp, Abitibi Subprovince, Superior Province, Québec, Canada. Application to VMS deposit exploration. Journal of Applied Geophysics, 2011, 75, pp.77-86. ⟨10.1016/j.jappgeo.2011.06.031⟩. ⟨insu-03619290⟩