Geology, geochemistry, and genesis of the Proterozoic MacLellan gold-silver Deposit, Lynn Lake Greenstone Belt, Manitoba.

Five, post-peak metamorphic hydrothermal events have been identified. Three events resulted in texturally and mineralogically distinct veins and associated alteration haloes. A fourth event, associated with late faults, resulted in quartz veins with no obvious associated wall-rock alteration. A fifth event, which occurred subsequent to the first stage of veining, contemporaneously with intense, heterogeneous, predominantly ductile deformation, resulted in shear zones comprising well-foliated greenschist facies mineral assemblages. Contrary to previous models, high-grade gold-silver mineralization within the deposit is epigenetic and occurs principally within Stage 3 arsenopyrite. Anomalous, sub-economic gold-silver concentrations are associated with Stage 1 pyrite and Stage 2 pyrrhotite. Stage 4 veins are generally barren of sulphide and gold mineralization but may be mineralized where they cut earlier veins. Precipitation of gold from hydrothermal fluids resulted from reaction of the fluids with iron contained in wall-rock oxide and silicate minerals. (Abstract shortened by UMI.)Dept. of Geology and Geological Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1991 .G345. Source: Masters Abstracts International, Volume: 30-04, page: 1246. Thesis (M.Sc.)--University of Windsor (Canada), 1991.