Magnetite, magnetite with associated hematite, and magnetite skarns form grossly conformable tabular deposits that have the forms of deformed sedimentary deposits. The host rocks, however, include gneisses of diverse composition and amphibolite. The iron oxides now present are late minerals that have replaced their host rocks. If the iron is primarily of sedimentary origin, the original rocks must have had compositions significantly different from those of known sedimentary iron deposits, even with allowance for significant later modification by hypogene solutions. 'An origin by direct contributions and emplacement by magmatic emanations has most support.'

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