header
  MetSoc Home            Publications            Contacts  
Search the Meteoritical Bulletin Database
Last update: 19 Sep 2020
Search for: Search type: Search limits: Display: Publication:
Names
Text help
Places
Classes
Years
Contains
Starts with
Exact
Sounds like
NonAntarctic
Falls  Non-NWAs
What's new
  in the last:
Include past classifications in search
Limit to approved meteorite names
Search text:  
Northwest Africa 11889
Basic information Name: Northwest Africa 11889
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 11889
Observed fall: No
Year found: 2017
Country: (Northwest Africa)
Mass:help 75 g
Classification
  history:
Meteoritical Bulletin:  MB 107  (2018)  CM2
Recommended:  CO3.1-an    [explanation]

This is the only approved meteorite classified as CO3.1-an.
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), CM-CO clan chondrites, and CO chondrites
Comments: Approved 3 Aug 2018
Revised 28 Mar 2020: reclassified
Writeuphelp
Writeup from MB 107:

Northwest Africa 11889 (NWA 11889)

(Northwest Africa)

Purchased: 2018

Classification: Carbonaceous chondrite (CM2)

Physical characteristics: Dark stone. Cut surface reveals homogeneous dark interior.

Petrography: (J. Gattacceca, CEREGE) Chondrules, some with fine grained dust rim, with average size 180±70 μm (N=20) set in a abundant fine grained iron rich matrix (61 vol% by point counting). Opaques are magnetite and troilite. No metal was observed. Low microprobe analyses totals in the matrix indicate the presence of phyllosilicates.

Geochemistry: Olivine Fa1.0-46.6, Cr2O3 0.25±0.14 wt% (n=10). Defocalized (10 µm) electron microprobe analyses in the matrix yield totals of 75 wt%.

Classification: CM2

Specimens: 23.5 g and a polished section at CEREGE. Main mass with R. Lenssen.


Writeup from MB 109:

Northwest Africa 11889 (NWA 11889), revised text and classification

Classification: CO3.1-anom

Physical characteristics: Dark stone. Cut surface reveals homogeneous brownish interior with small chondrules.

Petrography: (J. Gattacceca, CEREGE) Chondrules, some with fine-grained dust rims, with average size 180±70 μm (N=20,) set in a abundant, fine grained, iron-rich matrix (61 vol% by point counting). Opaques are magnetite and troilite. Magnetite is found as large spherical grains within chondrules. No metal was observed, except as rare µm-sized grains enclosed in silicates. XRD over a ~1 cm2 area on a polished section (D. Borschnek, CEREGE) does not reveal the presence of hydrous phases (serpentine, tochilinite) typically observed in type 2 chondrites.

Geochemistry: Olivine Fa11.1±15.8, Fa PMD 115%, range Fa0.6-53.3 (n=35), Cr2O3 in ferroan olivine 0.332±0.179 wt% (n=27). Low Ca pyroxene Fs4.3±2.2Wo2.1±1.1 (n=4), Ca pyroxene Fs1.2Wo36.1 (n=1). Matrix microprobe over areas of 20 × 20 µm2: total 80.1%, FeO 33.7 wt% (n=3). Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, CEREGE) from analysis of one acid-washed 1.5 mg aliquot of a powdered 144 mg bulk sample is δ17O=-5.33‰, δ18O=-1.20‰ , Δ17O=-4.71‰ (linearized, slope 0.5247, analytical uncertainties 0.08‰, 0.12‰, 0.03‰ respectively).

Classification: Carbonaceous chondrite (CO3.1-anomalous). The anomalous designation is from the high abundance of matrix, absence of metal and presence of magnetite as the main opaque phase. Subtype from the Cr2O3 content of ferroan olivine (similar to Colony CO3.1).

Specimens: 23.5 g and a polished section at CEREGE. Main mass with R. Lenssen.

Data from:
  MB107
  Table 0
  Line 0:
Place of purchase:Morocco/Western Sahara
Date:P 2018
Mass (g):75
Pieces:1
Class:CM2
Fayalite (mol%):6.7±13.4 (N=10)
Ferrosilite (mol%):1.3 (N=1)
Wollastonite (mol%):0.9
Magnetic suscept.:4.97
Classifier:J. Gattacceca, CEREGE
Type spec mass (g):23.5
Type spec location:CEREGE
Main mass:R. Lenssen
Comments:work name RL04; submitted by Jérôme Gattacceca
Plots: O isotopes:  
Institutions
   and collections
CEREGE: CEREGE BP 80 Avenue Philibert, Technopole de l'Arbois 13545 Aix-en-Provence Cedex 4 France, France (institutional address; updated 29 Oct 2018)
Catalogs:
References: Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
Published in Meteoritical Bulletin, no. 109, in preparation (2020)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7374 approved meteorites from (Northwest Africa) (plus 1957 unapproved names)

Direct link to this page