| MetSoc Home Publications Contacts |
|
||
|
||
| Northwest Africa 4937 | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Basic information | Name: Northwest Africa 4937 This is an OFFICIAL meteorite name. Abbreviation: NWA 4937 Observed fall: No Year found: 2007 Country: Morocco Mass:  212 g | ||||||||||||||||||||||||||
| Classification history: |
This is 1 of 87 approved meteorites classified as Winonaite. [show all] Search for other: Primitive achondrites, Winonaites | ||||||||||||||||||||||||||
| Comments: | Approved 17 Apr 2008 | ||||||||||||||||||||||||||
| Writeup |
Writeup from MB 94:
Northwest Africa 4937 Morocco Find: May 2007 Achondrite (winonaite) History: Purchased by an anonymous Moroccan dealer in Bir Elmalh Mahbas, Morocco, in May 2007. Physical characteristics: A brown, somewhat weathered stone (212 g, broken into several fragments) with visible metal and patches of brown fusion crust. Interior silicates are fresh, but metal is partly altered to reddish-brown iron hydroxides. Petrography: (A. Irving and S. Kuehner, UWS) Coarse grained (0.6–1.5 mm) protogranular aggregate of silicate phases (mostly sodic plagioclase, orthopyroxene and clinopyroxene) with abundant rounded to cuspate grains of metal (kamacite) and accessory olivine, schreibersite and troilite. No chromite was found. The estimated mineral mode is metal (+ altered metal) 40, plagioclase 28, orthopyroxene 20, clinopyroxene 10, others 2 (see image). Olivine is very rare, and occurs only as small round inclusions (up to 100 μm) within clinopyroxene. Geochemistry: Orthopyroxene (Fs7.4–7.9Wo2.4–2.7, FeO/MnO = 8.2–9.8, 0.52 wt% Cr2O3), clinopyroxene (Fs3.7–4.1 Wo40.6– 42.5, FeO/MnO = 6.3–8.1, 1.2 wt% Cr2O3), plagioclase (An14.9–18.6Or2.3–2.1), olivine (Fa7.0, FeO/MnO = 12.8). Oxygen isotopes (D. Rumble, CIW): δ18O = 4.370, 4.206; δ17O = 1.763, 1.738; Δ17O = -0.535, -0.474 (all‰). Classification: Achondrite (winonaite). This specimen is a metal-rich gabbro-norite that contains less than 0.1 vol% olivine, and is much coarser grained than typical winonaites, yet it has oxygen isotope affinities to the latter group. Specimens: A total of 20.1 g of sample and one polished mount are on deposit at UWS. The main mass is held by an anonymous collector. | ||||||||||||||||||||||||||
| Data from: MB94 Table 2 Line 91: |
|
||||||||||||||||||||||||||
| Plots: | O isotopes: | ||||||||||||||||||||||||||
| Institutions and collections |
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012) CIW: Carnegie Insitution Washington, Geophysical Laboratory, 5251 Broad Branch Rd., NW, Washington DC 20015, United States (institutional address) |
||||||||||||||||||||||||||
| Catalogs: |
| ||||||||||||||||||||||||||
| References: | Published in Meteoritical Bulletin, no. 94, MAPS 43, 1551-1588 (2008)
| ||||||||||||||||||||||||||
Geography:
|
Statistics: This is 1 of 2082 approved meteorites from Morocco (plus 31 unapproved names) (plus 1 impact crater) | ||||||||||||||||||||||||||
| Crosslinks: |
This lists all records that are linked to this record and to each other.
| ||||||||||||||||||||||||||
| Also see: |
This lists the most popular meteorites among people who looked up this meteorite.
| ||||||||||||||||||||||||||
| Revision history: |
This lists important revisions made to data for this record.
| ||||||||||||||||||||||||||