CATHODOLUMINESCENCE CHARACTERISTICS OF QUARTZ AND CARBONATE FROM THE ARCHEAN KIDD CREEK VMS DEPOSIT, ABITIBI SUBPROVICE, CANADA

The cathodoluminescence (CL) of quartz in ore, stockwork and crosscutting (younger) veins from the 2.72 Ga Kidd Creek volcanogenic massive sulfide (VMS) deposit, Abitibi Greenstone Belt, has been investigated using the “hot cathode” technique (HC1-LM system) to assess the potential of these various sample types to host hydrothermal fluid inclusions. The CL responses indicate that the various quartz types are of hydrothermal origin, and are therefore a potential host for primary hydrothermal fluid inclusions. Most notable is a transient (t < 120 s) blue CL, characteristic of hydrothermal quartz, observed in all samples. Furthermore, quartz CL in late (2.64 Ga) quartz-carbonate veins, which crosscut mine stratigraphy throughout the deposit and are similar in character to ‘flat’ veins associated with mesothermal gold mineralization in the Timmins district, reveals localized marginal zoning in quartz not apparent in transmitted light. Thus supporting a hydrothermal depositional origin of this quartz. Hydrothermal quartz occurs intimately intergrown with zinc-rich massive sulfides. This quartz locally shows zones of non-transient brown CL indicative of deformation. Quartz grain coarsening within these localized zones is consistent with deformational development. In one sample of massive sulfide ore, quartz CL reveals bright pinkish-white spots, tentatively interpreted as radiation haloes associated with radioactive microinclusions of monazite, xenotime, rutile and/or titanite within the quartz; these haloes are not apparent in transmitted light. Carbonate CL is characterized by intense orange to red emissions. In footwall stockwork ore CL reveals multiple carbonate-rich fluid pulses along microveinlets – these multiple pulses are not apparent in transmitted light. Carbonate CL in quartz-carbonate veins associated with post-ore (2.62 Ga) shearing clearly reveals multiple fluid pulses and the deformed nature of the veins. Widespread stable brown quartz CL mottling on a 10-50+ µm scale throughout these quartz-carbonate veins is consistent with deformation in a shear zone environment.