The Brunswick No.6 volcanogenic massive sulphide (VMS) Cu-ZONE, Bathurst Camp, New Brunswick, Canada: Petrology, geochemical composition, and petrogenesis

dc.contributor.advisorLentz, Dave
dc.contributor.authorMaclellan, Kirk L.
dc.description.abstractCu-rich massive sulphides envelope the north-end and base of the Brunswick No. 6 Pb-Zn massive-sulphide lens. Preliminary ore reserve calculations indicate 1.7 Mt grading 0.9% Cu. Mineralogically, the principle minerals identified are: pyrite, pyrrhotite, chalcopyrite, sphalerite, galena, magnetite, trace arsenopyrite, cobaltite, and cassiterite. Generally, chalcopyrite and pyrite are fine grained, although cataclastically deformed pyrite porphyroblasts (porphyroclasts) and pyritic massive sulphide boudins are hosted in a remobilized and recrystallized pyrrhotite-rich matrix. In this study, 11 sample intervals 5 feet long (1.62 m) from 1 O diamond drill holes (DOH) into the Cu zone were re-assayed yielding an average of 0.90% Cu, 1.28% Zn, 0.42% Pb, 28.6 g/t Ag, 0.046% Bi and 0.225 g/t Au, as well as 0.131 % As, 0.030% Sb, 0.069% Co and Sn values below the detection limit of 0.005%. Intervals in diamond Drill hole B-259 into the Pb-Zn (exhalative) zone were re-assayed (n = 6) and yielded an average of 0.78% Cu, 1.08% Pb, 3.46% Zn, 0.051% Bi, 0.311 % As, 0.063% Sb, 0.07% Co, 58.62 g/t Ag and 0.495 g/t Au. A similar trend occurs at the Brunswick No. 12 deposit. There is a notable decrease in Zn, Cu, Pb, Ag, As, and Sb concentrations with increased depth into the sheath-shaped basal Cu zone. Bi and Au concentrations exhibit a "U" shaped trend with the lowest concentrations occurring at approximately the centre of the Cu zone. Bulk sulphur analyses (n = 11) conducted on 1 O drill holes within the Cu zone yielded an average o 34S value of 14.6 per mil. Additionally, Hole B-259 sampled (n = 6) from the Pb-Zn (exhalative) zone averaged o 34S=14 per mil creating an increasing trend of of 34S values entering the Cu zone. The high Cu and low base-metals within the basal massive-sulphide zone compared to the Zn-Pb-Ag exhalative massive sulphides in both the No. 6 and No. 12 deposits is common in proximal VMS deposits. It is usually interpreted as a hydrothermal zone- refining feature located above the stockwork feeder zone, which is consistent with; 1) the relatively high pyrrhotite to pyrite abundance and higher abundance of chalcopyrite, arsenopyrite, bismuthinite, and cassiterite that have higher temperature-sensitive solubilities than the base metals that form the exhalative part of the deposit, 2) lower sphalerite, galena, tetrahedrite/tennantite, and argentite concentrations, and 3) it's occurrence above the stockwork feeder zone represents the main hydrothermal fluid discharge conduit that formed the deposit.
dc.description.copyrightNot available for use outside of the University of New Brunswick
dc.description.noteUniversity of New Brunswick. Department of Geology.
dc.format.extentix, 116 pages
dc.publisherUniversity of New Brunswick
dc.subject.disciplineEarth Sciences
dc.titleThe Brunswick No.6 volcanogenic massive sulphide (VMS) Cu-ZONE, Bathurst Camp, New Brunswick, Canada: Petrology, geochemical composition, and petrogenesis
dc.typesenior report Sciences of Science of New Brunswick