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| Northwest Africa 10769 | |||||||||||||||||||||||||||||||
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| 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:  149 g | ||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 21 approved meteorites classified as Chondrite-ung. [show all] Search for other: Ungrouped chondrites | ||||||||||||||||||||||||||||||
| Comments: | Approved 23 Aug 2016 | ||||||||||||||||||||||||||||||
| Writeup |
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: |
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| 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) |
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| Catalogs: |
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| References: | Published in Meteoritical Bulletin, no. 105, MAPS 52, 2411, September 2017. http://onlinelibrary.wiley.com/doi/10.1111/maps.12944/full
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Geography:
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Statistics: This is 1 of 235 approved meteorites from Western Sahara (plus 19 unapproved names) | ||||||||||||||||||||||||||||||