NWA 11253 (Anomalous Vesicular L-melt Rock)

One stone weighing 40g was purchased from a Moroccan dealer in 2017. A sample of this stone was sent to Dr. Anthony Irving who initially determined the stone to be a vesicular melt-textured metal poor ungrouped achondrite. The stone was recently presented and discussed at the 2017 Meteoritical Society Conference. The abstract can be downloaded in PDF format here: NWA11253abstract.  This stone will likely stand up to being one of the most vesicular stones ever found thus far, and among the most interesting theorize on its formation. Was it a product of impact melting or magmatism on the L-chondrite parent body? Or, is there a different explanation? NWA 11253 was approved after the conference as an L-melt rock with anomalous features, making it one of only one of several known to exist.

Only several slices are available as this was a small stone to begin with. Each slice was expertly prepared by Bob Falls and will come in a quality labeled meteorite display box.  EACH AND EVERY SLICE is LOADED with vesicles (see slanted view).

Petrography as follows:

Annealed microgabbroic texture (grainsize 0.1-0.4 mm) with vesicles. Some prismatic pyroxene grains are present, but grain boundaries between other grains exhibit triple junctions. Minerals are olivine, very finely exsolved pyroxenes (both low-Ca and high-Ca), oligoclase, chromite, merrillite, chlorapatite, troilite, very sparse but irregularly distributed kamacite (overall <0.2 vol.%, some as partly altered subspherical grains) and minor barite. Classification: L-melt rock (vesicular). This specimen apparently has affinities with L chondrites, but the paucity of metal and the presence of exsolution lamellae in pyroxenes are anomalous features.

Meteoritical Bulletin entry can be found here.

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