Indicator mineral and till geochemical signatures of the Mount Pleasant W-Mo-Bi and Sn-Zn-In deposits, New Brunswick, Canada

Abstract

A study of the till indicator mineral and matrix geochemical signature of the Mount Pleasant W-Mo-Bi and Sn-Zn-In deposits in New Brunswick, Canada was undertaken using commercially available methods. Indicator minerals of the deposits include: cassiterite, wolframite, and molybdenite, as well as gangue minerals topaz, chalcopyrite, galena, sphalerite, arsenopyrite, pyrite, and loellingite and secondary Pb minerals beudantite, anglesite, plumboferrite, and plumbogummite in the 0.25–0.5mm heavy mineral (>3.2 specific gravity) fraction, and fluorite in the 0.25–0.5mm mid-density (3.0–3.2 specific gravity) fraction. The presence of coarse (0.5–2.0mm) indicator minerals in till close (<1km) to the deposits marks the close proximity to mineralization. Indicator elements in the <0.063mm fraction of till overlying and down ice of the deposits include Sn, W, Mo, Bi, Zn, and In. Pathfinder elements in till include Ag, As, Cd, Cu, Pb, Re, Te, and Tl. This study reports In values of <0.02 to 13ppm in the matrix of till overlying the deposit; values >5ppm are some of the highest ever reported for till.