Exploration guidelines for stratiform zinc deposits in the Grenville Supergroup of the Mont-Laurier Basin, Quebec

CIM Bulletin, Vol. 73, No. 819, 1980

M. GAUTHIER and A.C. BROWN, Ecole Polytechnique, University de Montreal, Montreal, Quebec

Monometallic zinc mineralization associated with marbles of the Grenville Supergroup in the Mont-Laurier Basin of Quebec is found to be stratiform and to occur (1) within limited zones ofdolomitic marble and (2) more precisely along contacts between these marbles and adjacent metaclastic units. Massive sphalerite with accompanying pyrrhotite and pyrite is the prime exploration target, and commonly gives rise to good geochemical anomalies, but generally weak and ambiguous geophysical responses. Disseminated sphalerite in dolomitic marbles may signal proximity to interesting massive mineralization, although, due to weathering, this broadly disseminated mineralization may not be detected easily on outcrops. It is concluded that the western and possibly the eastern margin of the Mont-Laurier Basin constitute favourable areas for continued exploration.
Keywords: Stratiform deposits, Zinc, Grenville, Marble, Dolomite, Exploration, Geochemistry, Geophysics, Mont-Laurier Basin.