Implications of new geological mapping, geochemistry and Sm-Nd isotope data, Flin Flon area, Manitoba (part of NTS 63K12) by R-L. Simard and R.A. Creaser 1 GS-1

Summary Over the last two years, the rocks of the Flin Flon area have been the focus of a new 1:5000 scale bedrock mapping campaign aiming at the production of a new 1:10 000 scale stratigraphically coherent cross-border geological map, as part of the federal Targeted Geoscience Initiative (TGI-3). Using a combination of detailed volcanic facies analysis, structural mapping and thorough geochemical characterization of each unit in the area, this mapping campaign has allowed the recently established Flin Flon–Callinan–Triple 7 mine stratigraphy to be extended away from the main mines area south to Schist Lake. Rocks west of the Mandy Road Fault in the Schist Lake–Mandy mines area, approximately 5 km south of Flin Flon, are mainly juvenile tholeiitic, aphyric and pyroxene-plagioclase–phyric basaltic flows with a lesser amount of plagioclase-crystal–rich heterolithic mafic breccia. These rocks are most similar to those in the Hidden and Louis formation rocks, the hangingwall rocks of the Flin Flon–Callinan–Triple 7 mine. Rocks east of the Mandy Road fault, however, are heterolithic mafic breccia (not plagioclase-crystal rich) with minor aphyric basaltic flows and host the Schist Lake and Mandy volcanogenic massive sulphide (VMS) deposits. These rocks appear to be different from both the footwall and the hangingwall rocks of the Flin Flon–Callinan–Triple 7 mines. Mapping of the main structural elements in the Hidden Lake area, just south of the CN Rail line in the main Flin Flon–Callinan–Triple 7 mine stratigraphy, has highlighted a need for further work in that domain. Although individual structures such as the Hidden Lake syncline, the Railway Faults, the Missi wedge structure and the Ross Lake Fault can be readily documented, their relative timing is not satisfactorily resolved.