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Podiform Magmatic Deposit

Chemical Process (Liquid-phase Growth) - Closed system under ground (Melt precipitation)


Podiform chromitite, Podiform chromite deposit, Alpine chromite deposit

Required Geological Setting

Accretionary complexes


Chromite and spinel deposits accumulated from melt in magma chambers of island arcs or middle ocean ridges. Deposits are observed in cumulate rocks at the bottom of ophiolites and in blocks of ultramafic rocks associated with accretinary complexes. Hosts of the deposit are dunites or serpentinites. Deposits are composed of podiform massive ores and are discontineous with irregular pinch-and -swell structures. Boundaries between deposits and hosts are gradual. Harzburgite reacts with basaltic melt in fissures of Harzburgite masses to produce silica-rich melt and dunite as a residue around fissures. The reaction of this silica-rich melt with basaltic melt is considered to deposit chromite in fissures.

Podiform Magmatic Deposit

Distribution of podiform magmatic deposits described in this site. Yellow zones are metamorphic belts.

Mineral Assemblages

Chromite, Magnesiochromite, Spinel, Forsterite

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