NWA 13274 ( 11,681 g )

Northwest Africa 13274 (NWA 13274)
(Northwest Africa)
Purchased: 2019
Classification: Ungrouped achondrite
History: Purchased by Mark Lyon in December 2019 and January 2020 from two separate Moroccan dealers.
Physical characteristics: A total of eight similar-appearing brown stones (combined weight 255.5 g).
Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Analysis of two different stones shows this material to be composed predominantly of larger grains (mean size ~0.6 mm) of finely-exsolved low-Ca and high-Ca pyroxenes plus polygranular calcic plagioclase, together with accessory silica polymoprh, ferroan olivine, merrillite, chromite, ilmenite, Cr ulvöspinel, troilite and pentlandite (stained).
Geochemistry: Low-Ca pyroxene (Fs62.2-63.6Wo6.3-6.8, FeO/MnO = 60-65, N = 6), high-Ca pyroxene (Fs34.8-35.9Wo38.1-39.1, FeO/MnO = 60-69, N = 5), olivine (Fa72.1-82.0, FeO/MnO = 90-100, N = 4), plagioclase (An84.8-88.2Or0.3, N = 3).
Classification: Achondrite (ungrouped). Paired with NWA 011, NWA 2400, NWA 2976, NWA 4587, NWA 4901 and NWA 8545.
Specimens: 20.7 g including one polished thin section at UWB; remainder with Mr. M. Lyon.
 
Place of purchase:
Agadir; Tucson
Date:
P 2019
Mass (g):
255.5
Pieces:
8
Class:
Achondrite-ung
Shock stage:
low
Weathering grade:
low
Fayalite (mol%):
72.1-82.0
Ferrosilite (mol%):
62.2-63.6; 34.8-35.9
Wollastonite (mol%):
6.3-6.8; 38.1-39.1
Classifier:
A. Irving, UWS, and P. Carpenter, WUSTL
Type spec mass (g):
20.7
Type spec location:
UWB
Main mass:
M. Lyon
Comments:
Work name Lyon19-4; submitted by A. Irving