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Northwest Africa 10769
Basic information Name: Northwest Africa 10769
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 10769
Observed fall: No
Year found: 2015
Country: Western Sahara
Mass:help 149 g
Classification
  history:
Meteoritical Bulletin:  MB 105  (2016)  Chondrite-ung
Recommended:  Chondrite-ung    [explanation]

This is 1 of 25 approved meteorites classified as Chondrite-ung.   [show all]
Search for other: Ungrouped chondrites
Comments: Approved 23 Aug 2016
Writeuphelp
Writeup from MB 105:

Northwest Africa 10769 (NWA 10769)

Western Sahara

Purchased: Mar 2015

Classification: Ungrouped chondrite

History: Collected by nomads in Western Sahara and purchased by Nicola Castellano at the Bologna Mineral Fair in March 2015 from a Moroccan dealer.

Physical characteristics: A single piece weighing 149 g partially covered by fusion crust. The sawn surface displays chondrules set in a red-brown matrix with no metal spots.

Petrography: (V. Moggi Cecchi, G. Pratesi, S. Caporali, UniFi): The thin section displays a chondritic texture, with several chondrules set in a fine-grained matrix, mainly consisting of olivine and pyroxene. Chondrules range from 0.2 to 0.7 mm in diameter and are mainly PP type, with minor RP and C. Pyroxene crystals in PP chondrules are often rimmed by pigeonite. Chondrules account for about 70% of the total surface of the section. Opaque phases account for about 5% of the total area and are mainly pentlandite and Ni-rich pyrrhotite, partially weathered to iron oxides, while kamacite is very rare.

Geochemistry: (V. Moggi Cecchi, G. Pratesi, S. Caporali, UniFi) Matrix: olivine (Fa24.7±3.5, Fe/Mn=55±4, n=8, MD=1.76, PMD=7.76); low-Ca pyroxene (Fs14.6±5.0En84.4±5.2Wo0.9±0.2, 0.2 TiO2, 0.2 Al2O3, 0.2 Cr2O3, all wt. %; Fe/Mn=21±5, n=6 MD=2.47, PMD=25.48); Chondrules: olivine (Fa23.4±3.6, Fe/Mn=58±4, n=6, MD=2.38, PMD=11.06); low-Ca pyroxene (Fs14.4±5.1En84.6±4.9Wo0.9±0.2, 0.2 TiO2, 0.2 Al2O3, 0.2 Cr2O3, all wt. %; Fe/Mn=21±5, n=8 MD=2.49, PMD=25.52); pigeonite (Fs23.1±2.7En72.8±5.1Wo4.1±2.4, 0.2 TiO2, 0.8 Al2O3, 0.9 Cr2O3, all wt. %); Oxygen isotopes: (I. Franchi, R. Greenwood, OU) δ17O = 3.65 ‰, δ18O = 5.95 ‰, Δ17O = 0.55 ‰ (mean of two runs, bulk rock, 1 chip weighing 0.5 g); oxygen isotopes plot in a region above the TFL distinct from ordinary chondrites and at relatively high δ18O values.

Classification: The chondritic texture together with the presence of pentlandite and pyrrhotite and the absence of troilite point to a classification as an ungrouped chondrite; isotopic data and the compositional variability of Fa and Fs contents point to petrologic type 3.8; S1; W3

Specimens: A total of 20.8 g specimen is on deposit at MSN-Fi. Castellano holds two thin sections and the main mass.

Data from:
  MB105
  Table 0
  Line 0:
Place of purchase:Bologna
Date:P Mar 2015
Mass (g):149
Pieces:1
Class:Chondrite-ung
Shock stage:S1
Weathering grade:W3
Fayalite (mol%):24.7±3.5 (N=8)
Ferrosilite (mol%):14.4±5.1 (N=7)
Wollastonite (mol%):0.9±0.3
Classifier:V. Moggi Cecchi, S. Caporali, G. Pratesi, Uni-Fi
Type spec mass (g):20.8
Type spec location:MSN-FI
Main mass:Castellano
Comments:Submitted by Vanni Moggi Cecchi
Plots: O isotopes:  
Institutions
   and collections
OU: Planetary and Space Sciences Department of Physical Sciences The Open University Walton Hall Milton Keynes MK7 6AA United Kingdom, United Kingdom (institutional address; updated 8 Dec 2011)
MSN-FI: MUSEO DI STORIA NATURALE DELL'UNIVERSITA' DEGLI STUDI DI FIRENZE Via Giorgio La Pira, 4 – 50121 FIRENZE, Italy; Website (institutional address; updated 14 Jan 2015)
UniFi: Università degli Studi di Firenze, P.zza S. Marco, 4 - 50121 Firenze, Italy (institutional address; updated 14 Sep 2013)
Catalogs:
References: Published in Meteoritical Bulletin, no. 105, MAPS 52, 2411, September 2017. http://onlinelibrary.wiley.com/doi/10.1111/maps.12944/full
Find references in NASA ADS:
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Geography:

Western Sahara
Coordinates:Unknown.

Statistics:
     This is 1 of 207 approved meteorites from Western Sahara (plus 20 unapproved names)

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