Figure 2
Distribution of δ18O and δ13C values and numerical models for carbonates from Bergslagen. The analysed carbonates associated with magnetite-REE mineralisation in Bastnäs-type deposits (blue diamonds; this study) and complementary data (blue triangles) from Holtstam et al.31 are shown. Also shown are literature data for carbonates from the Bergslagen province (red dots)34, encompassing non-mineralised, Palaeoproterozoic marine carbonate rocks (blue field), carbonates from stratiform iron oxide deposits (purple field), carbonates from iron oxide skarn deposits (grey field), and carbonates from granite-related tungsten-molybdenum (W-Mo) skarn deposits (red field). Reference fields for Proterozoic marine calcite and dolomite (brown field)56 and primary magmatic waters (yellow field)35,37,38,39,40,41 are also included. Trajectories A-C represent Rayleigh-type de-volatilisation of local, non-mineralised marine carbonate rocks of average composition, using the indicated fractionation factors35. Lines 1–3 are binary mixing trajectories at 5% intervals between local marine carbonate rocks and a typical magmatic aqueous fluid composition. The calculated magmatic fluid-carbonate mixing trajectories envelop essentially all of the analysed carbonates from the Bastnäs-type deposits. See text for detailed explanation.
