L4-6 chondrite. 0.176g fragment. Sold in a collection box with label/certificate of authenticity.
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.