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Northwest Africa 13969
Basic information Name: Northwest Africa 13969
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13969
Observed fall: No
Year found: 2017
Country: (Northwest Africa)
Mass:help 102 g
Classification
  history:
Recommended:  C2-ung    [explanation]

This is 1 of 25 approved meteorites classified as C2-ung.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 2), and Ungrouped chondrites
Comments: Approved 17 Jul 2021
Writeuphelp
Writeup from MB 110:

Northwest Africa 13969 (NWA 13969)

(Northwest Africa)

Find: 2017

Classification: Carbonaceous chondrite (C2, ungrouped)

History: Several partially fusion-crusted stones weighing 102 g acquired by Ruben Garcia and Bob Cuchiara from Adam Aaronson at the 2017 Tucson Gem and Mineral show. 42 g was acquired by the Center for Meteorite Studies at ASU.

Physical characteristics: (L. Garvie, L. McCann, J. Miech, ASU) The largest fragment (27.3 g) is partly covered with ~0.3-1.0 mm in thick ropy fusion crust. The stones were noteworthy for being exceptionally light when picked up. The density of the 27.3 g stone is 1.56 g/cm3 (determined using glass bead methods with 100-µm sized beads). Microporosity estimated at 32% from BSE images. Total porosity estimated 46-51%, based on bulk grain densities of Murray and Murchison. The interior of the stones is dark gray-green with an abundance of small (<1 mm) chondrules and mineral fragments. Under the binocular microscope, the broken surfaces appear highly vesicular.

Petrography: (L. McCann, J. Miech, M. Hernandez, L. Garvie, ASU) A powder XRD pattern shows intense reflections for serpentine, tochilinite, olivine, magnetite/maghemite, calcite, and pentlandite. Low-magnification BSE images of the polished mount show abundant chondrules and chondrule fragments with fine-grained rims loosely packed together. The high porosity is evident as dark (BSE images) areas between the chondrules. Abundant porphyritic chondrules and rarer barred olivine chondrules, set within a serpentine-tochilinite dominated matrix. Chondrules have mean diameter of 268 µm (range=69-1277 µm, n=103). Chondrules primarily Type I (Mg # >90). Rare CAIs contain spinel, Al-rich pyroxene, hibonite, melilite, and perovskite and average ~135 µm (range 86-200 µm, n = 8). CAIs are mantled by thick fine-grained rims. Rare Mg-rich carbonates (average 126 µm in diameter, n = 9) are present. Rare metallic phases include a 10 µm kamacite grain within an olivine chondrule. Sparsely distributed 40-50 µm sulfides present in the form of pentlandite, pyrrhotite, and troilite. BSE images show euhedral fibrous tochilinite (to ~5 µm in length) within the pore spaces.

Geochemistry: Oxygen isotopes (K. Ziegler, UNM): 3 fragments analyzed by laser fluorination gave δ18O= -0.682, -3.272, -3.395; δ17O= -5.761, -7.509, -8.149; Δ17O=-5.400, -5.781, -6.357 (linearized, all per mil, TFL slope=0.528). Microprobe (L. McCann, J. Miech, M. Hernandez, A. Wittman, ASU):Two distinct populations of olivine, one with Fa2±1, n=58, Range: 0.5-6.4 and one with Fa34±11 n=19, Range: 17.2-57.7. Minor element phases in olivine CaO up to 1.8 wt%, Cr2O3 up to 0.6 wt%, NiO up to 0.1 wt%, Al2O3 up to 0.2 wt%. Pyroxene composition is En65-98, Fs1-34, Wo1-4 (n = 12).

Classification: C2 ungrouped. The stone has a type 2 petrographic type as evidenced by the serpentine dominated matrix . It contains abundant and relatively small chondrules and CAI. While mineralogically similar to CM chondrites, the oxygen isotopic compositions fall below CCAM at the lower end of the CV-CK field.

Specimens: 42 g at ASU.

Data from:
  MB110
  Table 0
  Line 0:
Place of purchase:Tucson
Date:2017
Mass (g):102
Pieces:23
Class:C2-ung
Weathering grade:low
Classifier:L. McCann, J. Miech, M. Hernandez, L. Garvie, K. Ziegler, A. Wittman
Type spec mass (g):42
Type spec location:ASU
Main mass:Ruben Garcia and Bob Cuchiara
Comments:ASU#2050; submitted by L. Garvie
Plots: O isotopes:  
Institutions
   and collections
ASU: Center for Meteorite Studies, Arizona State University, Tempe, Arizona 85287-1404, United States; Website (institutional address; updated 14 Jan 2012)
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010)
Catalogs:
References: Published in Gattacceca J., McCubbin F.M., Grossman J., Bouvier A., Chabot N.L., D'Orazio M., Goodrich C., Greshake A., Gross J., Komatsu M., Miao B., and Schrader D. (2022) The Meteoritical Bulletin, No. 110. Meteorit. Planet. Sci. 1-4
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Public domain photographs:
Laurence Garvie   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 8777 approved meteorites from (Northwest Africa) (plus 1879 unapproved names)

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