Entrèves meteorite, Entrèves, Courmayeur, Aosta Valley, Italyi

Regional Level Types
Entrèves meteorite	Meteorite Fall Location
Entrèves	Village
Courmayeur	Commune
Aosta Valley	Autonomous Region
Italy	- not defined -

Official name: Entrèves
Observed fall: no
Found: 1987, May
Coordinates (Catalogue of Meteorites): 45°49.14’N, 6°54.82’E
Approx. recovered weight: 17.3 kg
Iron, IAB-MG
Type spec. mass: a polished chip weighing 28 g is on deposit at MSN-FI ("La Specola" Museum of Natural History, Florence, Italy). Main mass with Giorgio Tomelleri.
Classifier: V. Moggi Cecchi, G. Pratesi and S. Caporali, UniFi (University of Florence, Florence, Italy)



A single 20x17x18 cm mass was found in 1987 by an anonymous bomb-slivers hunter near a moraine at the border of the Brenva glacier, west of Entrèves. The sample was subsequently sold to Claude Scavone, a French mineral collector who sold it to Giorgio Tomelleri, an Italian meteorite collector.

The main mass displays several small fusion pits and is apparently well preserved from rust. A distinct coarse grained Widmanstätten pattern is visible on sawn and etched surfaces. The 2x2 cm cut and etched chip examined by Moggi Cecchi et al. contains no silicates. Coarse-grained (~5 mm width) equigranular kamacite grains with 120° grain boundaries can be distinguished, with rare taenite. No Neumann lines are visible. Schreibersite is present as rare laths, up to 150 μm in width and to 1 mm in length, within some kamacite grains and at grain boundaries. Schreibersite is frequently surrounded by iron oxides.

SEM-EDX spot analyses, all in wt% (V. Moggi Cecchi, G. Pratesi and S. Caporali, UniFi): schreibersite Fe44.6±0.6Ni35.6±0.8P19.9±0.2 (N=6); taenite Fe70.5±0.5Ni29.5±0.2 (N=6); kamacite Fe92.6±0.6Ni7.4±0.2 (N=5). Bulk composition (C. Herd and G. Chen, University of Alberta, Edmonton, Canada): Ni=69.0, Co=4.5 (both mg/g); Cu=124, Ga=91, As=11.2, W=1.8, Ir=3.9, Pt=9.9, Pd=3.4, Ru=7.4, Re=0.4, Os=5.2, (all µg/g). Obtained by ICP-MS using North Chile meteorite as standard.

Classification: IAB-MG, coarse octahedrite. Composition is consistent with IAB Complex, Main Group (MG). The composition of this meteorite is extremely similar to that of Campo del Cielo. However Neumann bands are absent whereas they are abundant in Campo del Cielo.

References

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