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Magnetite grains from the Izok Lake (Nunavut, Canada) and the Halfmile Lake (New Brunswick, Canada) volcanogenic massive sulfide deposits, and from till covering the nearby areas were investigated using the scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and optical microscopy. The method of robust estimation for compositional data (rob-composition) was applied to censored geochemical data, and the results were analyzed by principal component analysis (PCA). Textural relationships and mineral association of magnetite reveal the history of formation, and contribute to the explanation of characteristic compositional differences of magnetite from different geological settings. The integration of petrography and mineral chemistry allows discriminating magmatic, metamorphic and hydrothermal magnetite …