Description
Mercantour has been abolished as a meteorite name due to significant doubt about the location and date of the find. As reported in Rochette et al. (2017), trace elements measurements (M. D’Orazio, UPisa) reveal a signature similar to that observed in meteorites found in hot deserts, with significant Ba and Sr enrichment. This meteorite is now called Nova 054. (information submitted by L. Ferrière).
The name Nova 054 replaces the discredited name Mercantour.
Mercantour 44.145°N, 7.311°E
Provence-Alpes-Cote d’Azur, France
Find: 2014 Sept 25
Classification: Ordinary chondrite (L4-6)
History: A systematic search of moraines and rocky surfaces by Eric Paillery led to this single discovery in the Southern Alps granitic massif, within Mercantour National Park, near 2900 m elevation.
Physical characteristics: A single angular fragment, covered ~30% by a relatively fresh fusion crust. Gray color with minor rust spots. Inner surface sometimes covered by a carbonate rind. Little patina visible. A few small rounded quartz grains inserted in cracks, with a light-orange soil matrix.
Petrography: Breccia with type 4 to 6 clasts (major class 4 to 5). Distinguishing type 4, 5 and 6 was done based on polished section observation of the morphology and overall texture of chondrules and metal grains. Mean chondrule diameter 707±39 μm. One fine-grained clast with low metal and troilite content was observed. Weathering at microscopic scale is hardly detectable but macroscopic rust spots indicate W1.
Geochemistry: Type 6 lithology: olivine Fa27.7 (n=1), orthopyroxene Fs21.2Wo0.7 (n=1). Type 4 lithology: olivine Fa24.7 (n=1), orthopyroxene Fs20.2Wo2.1 (n=1).
Classification: in the L group is based on magnetic susceptibility and chondrule size. Petrography (SEM and reflected optical microscopy) indicates a L4-6 breccia.
Specimens: 22.6 g at CEREGE.
