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NWA 16493: Achondrite Ungrouped

Class:Achondrite-ung

Shock stage:low

Weathering grade:low

Fayalite (mol%):40.1±0.4

Ferrosilite (mol%):38.9; 11.4±0.7

Wollastonite (mol%):3.6; 48.6±0.7

Magnetic suscept.:3.48

Classifier:A. Irving, UWS, P. Carpenter, WUSL, and J. Boesenberg, BrownU

Type spec mass (g):26.1

Type spec location:UWB

Main mass:F. Kuntz

This meteorite is metamorphosed chondrite, a type 7
This meteorite is a Carbonaceous
This meteorite is Ungrouped, unrelated to any other CC groups
It was proposed as a C7-ungrouped
It was accepted as a Achondrite Ungrouped

Classification: Achondrite (ungrouped, metamorphic, with oxygen isotope affinities to ungrouped carbonaceous chondrites). Although the olivine compositions in this meteorite could be consistent with an affinity to equilibrated R chondrites, the magnetic susceptibility and oxygen isotopic composition rule out such an affinity. Magnetic susceptibility is, however, within the range for CM chondrites, including specimens such as Mighei, Murchison and Murray (see Macke et al., 2011). The mean olivine composition is not inconsistent with the median olivine composition in unequilibrated CM2 and ungrouped C2 chondrites coupled with a contribution from regenerated olivine produced by dehydration of original cronstedtite in such thermally metamorphosed specimens (as described in PCA 91018, PCA 02010 and PCA 02012 by King et al. (2021). The prevalence of Ni-bearing sulfides and paucity of metal are also consistent with an affinity to CM or similar carbonaceous chondrites. However, the oxygen isotopic composition plots significantly below the CCAM trend and the field for CM chondrites to more negative Δ17O values, and lies on the same trend as values for ungrouped carbonaceous chondrites such as Telakoast 001 and similar specimens Irving et al. (2022). The prevalence of Fe oxides, augite and intermediate plagioclase would be consistent with CK chondrites; however, the oxygen isotopes do not support an affinity with those meteorites.

NWA 14693 - Ox.png
NWA 14693 - BSE.bmp

Oxygen isotopes and BackScattered Electrons (BSE) microscopy image for NWA 16493

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Slice  - 0.75g- 112$ - SOLD

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Slice  - 1.08g- 162$

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Slice  - 0.69g- 103$ - SOLD

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Slice  - 1.40g- 210$ - SOLD

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NWA 16493 - 09.JPG

Slice  - 4.58g- 687$

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Slice  - 4.49g- 673$ - SOLD

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NWA 16493 - 14.JPG

Slice  - 7.06g- 1059$

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NWA 16493 - 15.JPG

Slice  - 12.00g- 1620$

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