SÃO JOÃO NEPOMUCENO

Iron

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ACHONDRITE

FINE OCTAHEDRITE

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IVA

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BRAZIL - MG

1960

Iron Meteorite - IVA Fine Octahedrite.

PETROGRAPHY:

The São João Nepomuceno meteorite after being attacked with Nital solution exhibits a well-defined Widmanstätten pattern (width 0.35 +/- 0.1 m), being, therefore, a fine octahedrite. It belongs to the IVA - anomalous group, containing numerous inclusions of silicates, polycrystalline. Description obtained from the documents of National Museum.

GEOCHEMISTRY:

(Silveira, M. R. V.) Fe 91.60%; Ni 7.92%; Co 0.4%; Po 0.54%; S 0.008%; Si 0.018%; Cu <0.01%; As <0.001%. Values obtained from the documents of National Museum. Values provided by the Meteoritical Bulletin Database: 8.0% Ni, 2.16 ppm Ga, 0.118 ppm Ge, 2.6 ppm Ir.

CLASSIFICATION:

The São João Nepomuceno meteorite is a fine octahedrite of the IVA group, showing a well-developed fine Widmanstätten structure.

CLASSIFIERS:

J.T. Wasson, dezembro de 1979 and A. Kracher et al. (1980).

HISTORY:

A siderite weighing about 15 kg and measuring 54 x 20 x 11 cm was found near São João Nepomuceno and donated to the National Museum by Dr. Sylvio Froes de Abreu, then director of the National Institute of Technology. Subsequent inquiries in that city came to question the correct origin. Description obtained from the documents of National Museum.

All information that does not have a specific source was extracted from the Meteoritical Bulletin Database.

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