In situ laser ablation quadrupole inductively coupled plasma mass spectrometry was used to measure Pb isotopes in galena. Data acquisition was optimized by adjusting spot size, energy density, and ablation time to obtain near steady-state low relative standard deviation (%RSD) signals. Standard-sample bracketing using in-house Broken Hill galena as external reference standard was used and offline data reduction was carried out using VizualAge for Iolite3. Using this methodology, galena grain in polished thin sections from selected massive sulphide deposits of the Bathurst Mining Camp, Canada, were tested and compared to previously published data. Absolute values and errors on the weighted mean of ~20 individual analyses from each sample compared favourably with whole-rock Pb-Pb isotope data. This approach provides a mean to obtain rapid, accurate, and moderately (0.1% 2σ) precise Pb isotope measurements in galena and is particularly well suited for exploratory or reconnaissance studies. Further refinement of this approach may be useful in exploration for volcanogenic massive sulphides deposits and might be a useful vectoring tool when complemented with other conventional exploration techniques.

The compositions of phyllosilicates, with a focus on fluid-mobile elements, were evaluated as a means to fingerprint the Middle Ordovician metamorphosed (greenschist facies) volcanogenic massive sulfide deposits of the Bathurst Mining Camp (BMC), Canada. Ninety-five drill-core samples from six of the major deposits of the Bathurst Mining Camp (Brunswick No. 12, Heath Steele B zone, Halfmile Lake Deep zone, Key Anacon East zone, Louvicourt, and Restigouche) were analyzed using electron microprobe and laser ablation inductively coupled plasma-mass spectrometry. Typically, phyllosilicates (chlorite, white mica, and to a lesser extent biotite) are ubiquitous phases in the host rocks of the massive sulfide deposits of the BMC. Electron microprobe analysis results show a wide compositional variation in chlorite and white mica. Laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis was performed to measure fluid-mobile elements, showing that Tl is distinctly enriched in all white mica (up to 719 ppm) relative to chlorite (up to 50.1 ppm). Chlorite hosts Sn (up to 4600 ppm), Hg (up to 7.3 ppm), Sb (up to 35.4 ppm), As (up to 1320 ppm), In (up to 307 ppm), Cd (up to 83.2 ppm), and Se (up to 606 ppm). White mica hosts Sn (up to 1316 ppm), Hg (up to 93 ppm), Sb (up to 1630 ppm), As (up to 14,800 ppm), In (up to 1186 ppm), Cd (up to 98 ppm), and Se (up to 38.8 ppm). Limited LA-ICP-MS analysis on biotite indicates a higher overall concentration of Tl (mean = 14.6 ppm) relative to co-existing white mica (mean = 2.18 ppm). On average, biotite is also more enriched in Hg, Sn, and Ba relative to chlorite and white mica. Laser Ablation ICP-MS profiles of chlorite, white mica, and biotite demonstrate smooth time-dependent variations diagnostic of structural substitution of these elements. Compositional variation of chlorite-white mica pairs presented in the current study shows systematic variations as a function of distance from the mineralized horizons. This highlights the potential to use trace-element signatures in these phyllosilicate pairs to identify proximal (chlorite) and distal (white mica) footprints for volcanogenic massive sulfides exploration.

Several of the Middle Ordovician polymetallic Zn-Pb-Cu-Ag volcanogenic massive sulfide deposits of the Bathurst Mining Camp (BMC), northern New Brunswick, Canada, were investigated using laser ablation inductively coupled plasma-mass spectrometry. Quantitative and semi-quantitative analysis of a suite of fluid-mobile elements (As, Bi, Cd, Hg, In, Ga, Ge, Sb, Se, Sn, Te, and Tl) was conducted for pyrite, chalcopyrite, pyrrhotite, sphalerite, galena, arsenopyrite, and tetrahedrite–tennantite. The occurrence of fluid-mobile elements within different sulfide assemblages shows mineral-specific characteristics and genetically controlled features. Our results show that subsequent metamorphism and deformation modified and redistributed the fluid-mobile elements at the mineral scale, which is texturally controlled. In addition, the fluid-mobile elements within sphalerite and chalcopyrite distinctly differentiate the hydrothermal facies.