Abstract:

The Schist Lake and Mandy volcanogenic massive sulphide (VMS) deposits are located 5 km east of the town of Flin Flon in Northern Manitoba. The main goals of this thesis are to: 1) to characterise and describe the host rocks to the Schist Lake and Mandy volcanogenic massive sulphide deposits and their associated hydrothermal alteration zones; 2) to compare the host rocks and the volcanic environment of these VMS deposits to those of the main Flin Flon camp; and 3) to determine if the Schist Lake and Mandy VMS deposits are time stratigraphic equivalent to VMS deposits in the main Flin Flon camp, or to the rocks of the Hook Lake Block? These questions were tested using detailed geological mapping, logging of drill core, petrography, and lithogeochemistry.<br/>Strata of the Schist Lake and Mandy mines area are divisible into four informal units which, from oldest to youngest include: 1) the Lower Mafic volcaniclastic unit; 2) the Middle Mafic volcaniclastic unit; 3) the Bedded Tuff unit; and 4) the Upper Mafic volcaniclastic unit. The Schist Lake and Mandy VMS deposits are hosted by a quartz porphyry with localised sericite schist within a thicker succession of mafic volcaniclastic of the Lower Mafic volcaniclastic unit. The Schist Lake deposit has an alteration zone consistent with that of typical bimodal mafic VMS deposits consisting of an inner chlorite core and an outer sericite zone with pervasive silica alteration throughout. The deposit and alteration halo have been transposed during regional deformation by deformation associated with the Mandy Road fault; the latter bisects the map area. Geochemical comparison of the Middle and Lower Mafic volcaniclastic units on either side of the Mandy Road fault indicate that there is no significant geochemical difference between the units. Therefore, the Mandy Road fault is not interpreted as a significant block bounding structure and mafic volcaniclastic units on either side of the fault are compositionally and physically similar. This, along with the physical and compositional similarity between the Upper Mafic volcaniclastic unit and the Hidden formation, the Bedded Tuff unit with the Millrock member and the Middle and Lower Mafic volcaniclastic units with the Millrock<br/>member mafic flows and volcaniclastic rocks are consistent with the interpretation that they maybe stratigraphically equivalent to strata of the Flin Flon Block. Thus, the Schist Lake and Mandy VMS deposits are interpreted to be the stratigraphic equivalent of the Flin Flon, Callinan and 777 VMS deposits that make up the main Flin Flon VMS district.