Abstract

Zones of Fe-Zn-Pb-Cu sulfide mineralization exposed in the Strickland area of southwestern Newfoundland are interpreted to represent diverse portions of one or more volcanogenic massive sulfide deposits which have been subjected to cataclastic deformation and greenschist facies metamorphism. We suggest that both alteration and mineralization are related to fluid convection driven by the subvolcanic Baggs Hill Granite. A total of 294 surface and 292 drill core samples were analyzed for major elements and a range of trace elements, and the data assessed by discriminant function and regression analysis. Residual values were calculated from the regression equations and are plotted on maps and dip surface plots to illustrate the discontinuous and sporadic distribution of anomalies on a local scale. The most outstanding are marked by depletion of Na 2 O, CaO, and Al 2 O 3 and addition of K 2 O and SiO 2 . Local zones of carbonate-tremolite alteration associated with Ag mineralization, marked by Mg enrichment, are interpreted to represent metamorphosed chemical sediments. On a regional scale, the felsic volcanic rocks of the Strickland area are anomalously low in Na 2 O compared to equivalent lithologies outside the area (1.14 vs. 4.17% average Na 2 O). This constitutes a significant regional exploration guide, although lithogeochemical anomalies are more complex on a local scale.

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