Mineral-Fluid Equilibria in Iron-Formation in the Aureole of the Duluth Gabbro

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9627829 Frost This pilot study will concentrate on the relations of the LTV mine in the Biwabik iron formation. With increasing grade, individual siderite layers in the aureole become oxidized to magnetite. The PIs will attempt to determine the process by which this oxidation occurred. Carbon and oxygen isotopes will be used to determine whether the formation of the magnetite was preceded by simple oxidation or by formation of metastable methane. Each process should produce a distinctive isotopic signature. Ion microprobe analyses of the silicates and carbonates will be performed o determined the temperature and fluid compositions that were present at the time of oxidation. The magnetite-hematite relations in low grade rocks will also be investigated.