Abstract

Meguma Group lode gold deposits represent concentrations of a variety of auriferous quartz veins in lower Paleozoic metaturbidites of the Meguma terrane of southern Nova Scotia. Our studies, incorporating extensive field (regional and detailed mapping) and laboratory (petrography, fluid inclusions, geochemistry, isotopes) studies of 30 of these deposits in the eastern Meguma terrane, suggest that mineralization occurred at ca. 370 Ma (40Ar/39Ar dating of hydrothermal vein minerals) during widespread incursion of mafic and felsic magmatism into the crust concurrent with subvertical shear-zone development, thus postdating regional Acadian deformation by some 30-40 m.y. Isotopic data (S, C, O, Sr) indicate that vein-forming fluids were not solely magmatic and were in part exotic to the Meguma Group. Thus, earlier magmatic and metamorphogenic-lateral-secretion models that considered either late-stage magmatic fluids or the enveloping Meguma Group metasedimentary rocks as the sole source of vein components are invalidated.

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