NWA 12416 – 1.74g

$175.00

1 in stock

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Description

C3-ung

Fragment – 1.74g.
Sold in a membrane box with label/certificate of authenticity.


Northwest Africa 12416 (NWA 12416)
(Northwest Africa)
Purchased: 2018 Jul
Classification: Carbonaceous chondrite (C3, ungrouped)
History: The first batch of this material was purchased by Adam Aaronson in July 2018 in Temara, Morocco; subsequently additional material was purchased from the same Moroccan source by Mark Lyon and others.
Physical characteristics: The material consists of numerous small black, friable stones, some completely fusion crusted (total weight 875 g).
Petrography: (A. Irving and S. Kuehner, UWS; L. Garvie, ASU) Granular chondrules (apparent diameter 350±210 µm, N = 15) together with sparse mineral fragments and AOA (but no identifiable CAI or related mineral grains) are set in very fine grained matrix (~50 vol.%, black in thin section) containing minor kamacite and pentlandite. No phyllosilicates were detectable by X-ray diffraction.
Geochemistry: Olivine (Fa1.0-67.1, N = 3), orthopyroxene (Fs1.7-4.3Wo0.9-3.1, N = 2), clinopyroxene (Fs1.1Wo23.2). Oxygen isotopes (K. Ziegler, UNM) Analyses of acid-washed subsamples by laser fluorination gave, respectively, δ17O -10.290, -0.181, -11.117; δ18O -6.827, 7.352, -7.023; Δ17O -6.685, -4.063, -7.409 per mil.
Classification: Carbonaceous chondrite (ungrouped Type 3). Oxygen isotope compositions plot at more negative Δ17O values than for CV, CK and most CM chondrites, and the absence of phyllosilicates excludes affinity to typical CM2 chondrites.
Specimens: 20.1 g including one polished thin section at UWB; 152 g at ASU; 361 g with Mr. M. Lyon; 137 g with Mr. M. Ouzillou; 205 g with Mr. A. Aaronson.

Mass (g): 875
Pieces: many
Class: C3-ung
Shock stage: low
Weathering grade: low
Fayalite (mol%): 1.0-67.1
Ferrosilite (mol%): 1.7-4.3
Wollastonite (mol%): 0.9-3.1
Classifier: A. Irving and S. Kuehner, UWS
Type spec mass (g): 20.1
Type spec location: UWB
Main mass: A. Aaronson/M. Lyon/M. Ouzillou
Comments: Work name M2151; submitted by A. Irving