Examination Of Glacial Dispersal And Use Of Cold Vapor Atomic Fluorescence Spectrometry At Mount Fronsac North New Brunswick

"The mobility of mercury in both bedrock and surficial environments has made it an ideal geochemical pathfinder element in detecting buried ore deposits for over 80 years. Recent advances in analytical techniques, specifically cold vapor atomic fluorescence spectrometry have made it possible to determine minute (0.05 ppb) concentrations of mercury in geological materials. This analytical method was successfully used to determine mercury concentrations in 236 C-horizon (till) samples overlying the Mount Fronsac North volcanogenic sediment hosted massive sulfide (VSHMS) deposit in the BMC, northern New Brunswick. Concentrations for 53 elements were determined using ICP-MS/ES analysis. Mercury concentrations analyzed by ICP-MS show high correlation with concentrations found by cold vapor atomic fluorescence spectrometry. From mapping till geochemical data, three dispersal patterns were observed in glacial till: 1) palimpsest (Pb, Ag, Cu, As, Sb, Au, Mo), related to pre-glacial colluvial distribution of mineralized gossan, 2) ribbon (Ni, Co, Cr), related to the occurrence of a gabbro and Mnrich shales in rocks surrounding the mineralized zone and 3) an arcuate pattern (Hg, Cd,) related to bedrock alteration and possible post-glacial ionic mobility. Concentration gains of Mo, As, Sb, Cu V and Hg in gossan and gains of Zn, Au, Cd, V, Ba, Co, Se, Sr and Hg in till were calculated using tin (Sn) as a conservative element. Concentration gains and losses of elements in till indicate the main processes responsible for element signatures in till over the Mount Fronsac North deposit are complex and can be attributed to five processes: 1) formation of element halos from ore deposition, 2) preglacial weathering of primary sulfides resulting in gossan formation, 3) pre-glacial colluvial and hydromorphic redistribution of gossanous material, 4) west to east and southwest to northeast mechanical transport of mineralized bedrock by glaciers and 5) ionic migration of cations and anions due to electrochemical reactions between wall rock and sulfides."--Pages iii-iv.