| MetSoc Home Publications Contacts |
|
||
|
||
| Northwest Africa 7988 | |||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Basic information | Name: Northwest Africa 7988 This is an OFFICIAL meteorite name. Abbreviation: NWA 7988 Observed fall: No Year found: 2013 Country: (Northwest Africa) Mass:  116 g | ||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 2954 approved meteorites (plus 2 unapproved names) classified as LL6. [show all] Search for other: LL chondrites, LL chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7) | ||||||||||||||||||||||||||||||
| Comments: | Approved 23 Jun 2014 | ||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 103:
Northwest Africa 7988 (NWA 7988) (Northwest Africa) Purchased: 2013 Jul Classification: Ordinary chondrite (LL6) History: Purchased by M. Ouzillou in July 2013 from a dealer in Zagora, Morocco. Physical characteristics: Very fresh specimen (116 g) with partial black fusion crust composed of darker gray clasts (up to 1.1 cm across) in a lighter gray matrix. Minor terrestrial staining of sulfides locally present. Petrography: (A. Irving and S. Kuehner, UWS; M. Zolensky, JSC) Fresh, highly recrystallized breccia. A single identifiable chondrule was found within the thin section. Composed of olivine, clinopyroxene, orthopyroxene, sodic plagioclase, troilite, unaltered Ni-rich metal (taenite) and Ti-bearing chromite (rimmed by ilmenite). Troilite and Ni-rich metal commonly form composite grains, but no kamacite is present. Geochemistry: Olivine (Fa32.0-32.1; FeO/MnO = 60-61), orthopyroxene (Fs24.1-25.5Wo1.7-1.9), clinopyroxene (Fs10.4Wo43.2), metal (Ni 61.0 wt.%, Fe 37.1 wt.%, Co 1.0 wt.%). Oxygen isotopes (K. Ziegler, UNM) Analyses of acid-washed subsamples by laser fluorination gave, respectively (all in per mil) δ17O = 3.765, 3.873; δ18O = 4.914, 5.155; Δ17O = 1.170, 1.151 (for a TFL slope of 0.528). Classification: Ordinary chondrite (LL6). The major mineral compositions and oxygen isotopes are consistent with an LL chondrite affinity, but the complete lack of kamacite, abundance of troilite, very Ni-rich taenite, and the Ti-rich chromite + ilmenite assemblage are rare features in comparison with typical LL chondrites. Specimens: 21 g and one polished thin section are at UWB. The remainder is held by Mr. M. Ouzillou. | ||||||||||||||||||||||||||||||
| Data from: MB103 Table 0 Line 0: |
|
||||||||||||||||||||||||||||||
| Plots: | O isotopes: | ||||||||||||||||||||||||||||||
| Institutions and collections |
JSC: Mailcode XI, 2101 NASA Parkway, NASA Johnson Space Center, Houston, TX 77058, United States; Website (institutional address; updated 28 Jul 2022) 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) UWB: University of Washington, Burke Museum of Natural History and Culture, Box 353010 Seattle, WA 98195, United States (institutional address; updated 9 Oct 2023) |
||||||||||||||||||||||||||||||
| Catalogs: |
| ||||||||||||||||||||||||||||||
| References: | Published in Meteoritical Bulletin, no. 103, MAPS 52, 1014, May 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12888/full
| ||||||||||||||||||||||||||||||
| Geography: |
Statistics: This is 1 of 9914 approved meteorites from (Northwest Africa) (plus 1841 unapproved names) | ||||||||||||||||||||||||||||||