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Northwest Africa 13671
Basic information Name: Northwest Africa 13671
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13671
Observed fall: No
Year found: 2020
Country: Algeria
Mass:help 35 g
Classification
  history:
Recommended:  C3-ung    [explanation]

This is 1 of 26 approved meteorites classified as C3-ung.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), and Ungrouped chondrites
Comments: Approved 8 Apr 2021
Writeuphelp
Writeup from MB 110:

Northwest Africa 13671 (NWA 13671)

Algeria

Purchased: 2020 Jul

Classification: Carbonaceous chondrite (C3, ungrouped)

History: Purportedly found near Umm al-Asal, Algeria. Purchased by Didi Baidari in July 2020 and subsequently sold to Ziyao Wang.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL; L. Garvie, ASU) Small Mg-rich chondrules (apparent diameter 140 ± 80 µm, N = 25) and zoned olivine fragments are set in a finer grained matrix (~60 vol.%, black in thin section) containing olivine and pyroxene which are much more Fe-rich. Accessory phases identified by EPMA include calcic plagioclase, Fe sulfide, taenite, pentlandite and calcite. No phyllosilicates were detected by X-ray powder diffraction, but prominent reflections were observed for olivine (predominantly Fe rich and fine-grained), clinoenstatite, calcite, pyrrhotite, pentlandite and minor Fe3O4.

Geochemistry: Olivine in chondrules (Fa2.2±2.0, range Fa0.9-4.9, N = 6), olivine single crystal (core Fa32.1, rim Fa45.8), olivine in matrix (Fa35.2±15.7, range Fa15.8-59.5, N = 5), low-Ca pyroxene in chondrules (Fs0.9Wo3.9; Fs0.9Wo6.0; N = 2), diopside in chondrules (Fs1.0Wo37.4; Fs0.9Wo42.6; N = 2), more ferroan low-Ca pyroxene in matrix (Fs6.8Wo2.1). Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively, δ17O -6.803, -7.345. -6.024; δ18O -1.855, -2.334, -1.505; Δ17O -5.824, -6.113, -5.229 per mil (all data linearized).

Classification: Carbonaceous chondrite (C3 ungrouped). Chondrule sizes are much too small for this to be a CV or CK chondrite. Oxygen isotopes plot below the CCAM line and do not fall on the trend for CO chondrites. Any affinity of this specimen to CM chondrites (including anhydrous CM-an specimens NWA 11024, NWA 11086, NWA 11254 and NWA 11346) is ruled out by its much lower δ18O values.

Specimens: 7.6 g including one polished mount at UWB; remainder with WangZ.

Data from:
  MB110
  Table 0
  Line 0:
Place of purchase:Tindouf, Algeria
Date:P 2020 Jul
Mass (g):35
Pieces:2
Class:C3-ung
Shock stage:S2
Weathering grade:low
Fayalite (mol%):2.2±2.0; 35.2±15.7
Ferrosilite (mol%):0.9; 0.9; 6.8
Wollastonite (mol%):3.9; 6.0; 2.1
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):7.6
Type spec location:UWB
Main mass:WangZ
Comments:Work name DB-2; submitted by A. Irving
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)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
WangZ: Ziyao Wang, Hebei GEO University North Campus, Huai An dong road 127, Shijiazhuang, Hebei Province , China (private address; updated 25 Jun 2021)
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
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Ziyao Wang               
Public domain photographs:
A. Irving   
Geography:

Algeria
Coordinates:Unknown.

Statistics:
     This is 1 of 1236 approved meteorites from Algeria (plus 29 unapproved names) (plus 4 impact craters)

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