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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 22 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 Meteoritical Bulletin, no. 110, in preparation (2021)
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 1140 approved meteorites from Algeria (plus 27 unapproved names) (plus 4 impact craters)

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