![]() |
||
|
Northwest Africa 7611 | |||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Basic information | Name: Northwest Africa 7611 This is an OFFICIAL meteorite name. Abbreviation: NWA 7611 Observed fall: No Year found: 2012 Country: Morocco Mass: ![]() | ||||||||||||||||||||||||||
Classification history: |
This is 1 of 103 approved meteorites classified as Lunar. [show all] Search for other: Lunar meteorites | ||||||||||||||||||||||||||
Comments: | Approved 1 Jan 2013 | ||||||||||||||||||||||||||
Writeup![]() |
Writeup from MB 102:
Northwest Africa 7611 (NWA 7611) Morocco Found: May 2012 Classification: Lunar meteorite History: Reportedly found near the Moroccan/Algerian border in May 2012. Purchased from a Moroccan meteorite dealer in 2012. Physical characteristics: Single 916 g stone, no fusion crust, smooth exterior with numerous light- and dark-colored clasts, saw cuts reveal brecciated texture with white feldspar and green-brown pyroxene and olivine grains (up to 3 mm) set in a darker gray-green matrix; scattered gabbroic and dark clasts up to 1 cm. Petrography: (C. Agee, UNM; A. Irving, UWS) Microprobe examination of a polished 7 × 2 cm sawn slice and a separate polished mount shows a fragmental breccia of plagioclase, pyroxene, and olivine grains in a wide range of grain sizes. A prominent ~1-cm pyroxene-plagioclase gabbroic clast was observed as well as several smaller gabbroic fragments. One small clast consists of intergrown hedenbergite+fayalite+silica (after pyroxferroite). The groundmass is variable with some domains showing a uniform fine-grained subophitic plagioclase-pyroxene texture, while other domains show densely packed mineral clasts ranging from 10-300 μm. There are several sharp boundaries between the various textural domains, with at least two compositionally distinct olivine populations, and a wide range of pyroxene compositions, indicating multiple lithologies of a mingled fragmental breccia. Accessory ilmenite, silica polymorph, minor zircon, troilite, Ti-bearing chromite, Ni-free iron metal and kamacite are present. Geochemistry: (C. Agee and M. Spilde, UNM; A. Irving and S. Kuehner, UWS). Fayalitic olivine Fa90.6±5.7, Fe/Mn=90±4, n=15; forsteritic olivine Fa31.6±11.1, Fe/Mn=93±9, n=3; pyroxene Fs43.6±13.3Wo20.2±8.5, Fe/Mn=67±8, n=37; pyroxene in gabbroic clast Fs45.3±13.1 Wo15.4±5.3, Fe/Mn=69±7, n=12; plagioclase An93.5±1.5Ab6.0±1.4Or0.5±0.5, n=13. Bulk composition (R. Korotev, WUSL). INAA on 4 subsamples gave the following mean values: Na2O=0.405, CaO=14.8, FeO=11.27 (wt%); Sc=25.1, Cr=1692, Co=37.6, Ni=181, La=6.38, Nd=8.9, Sm=3.07, Eu=0.891, Lu=0.321, Hf=2.12, Ir=0.0044, Au=0.0036, Th=0.97, U=0.36 (ppm). Oxygen Isotopes, laser fluorination (K.Ziegler, UNM), 6 analyses on 3 acid-washed aliquots gave mean values δ17O=3.161±0.080, δ18O=5.931±0.031, Δ17O=0.030±0.075 (linearized, all permil). Classification: Achondrite (lunar, mingled breccia), high bulk FeO and Sc, and fayalitic olivines suggest the presence of a mare basalt component. Specimens: A total of 20 g is on deposit at UNM. The remainder is divided between Jay Piatek, Matt Morgan, Mike Hankey, and Haag; Jay Piatek holds the main mass. | ||||||||||||||||||||||||||
Data from: MB102 Table 0 Line 0: |
|
||||||||||||||||||||||||||
Plots: | O isotopes: | ||||||||||||||||||||||||||
Institutions and collections |
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) Haag: Robert Haag, P.O. Box 27527, Tucson, AZ 85726, United States; Website (private address) |
||||||||||||||||||||||||||
Catalogs: |
| ||||||||||||||||||||||||||
References: | Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015
| ||||||||||||||||||||||||||
Photos: |
| ||||||||||||||||||||||||||
Geography:![]() |
Statistics: This is 1 of 1991 approved meteorites from Morocco (plus 31 unapproved names) (plus 1 impact crater) |