Chemostratigraphy and origin of the late Archean siderite–pyrite-rich Helen Iron Formation, Michipicoten belt, Canada

@inproceedings{Goodwin1985ChemostratigraphyAO,
  title={Chemostratigraphy and origin of the late Archean siderite–pyrite-rich Helen Iron Formation, Michipicoten belt, Canada},
  author={Anne M. Goodwin and Henry George Thode and C.-L. Chou and S. N. Karkhansis},
  year={1985}
}
The 2.7 Ga old Helen Iron Formation (HIF) with its uniquely large siderite–Pyrite orebody conformably overlies chemically altered rhyolite–dacite pyroclastic rocks, including an ottrelite-bearing alteration pipe, the product of exhalative venting in freshly accumulated pyroclastics. HIF, in turn, is conformably overlain by pillowed mafic lava flows.HIF internal stratigraphy is conformable from lower massive siderite–sulfide through middle sulfidic, carbonaceous chert, to upper magnetitic chert… CONTINUE READING