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| Northwest Africa 2994 | |||||||||||||
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| Basic information | Name: Northwest Africa 2994 This is an OFFICIAL meteorite name. Abbreviation: NWA 2994 Observed fall: No Year found: 2007 Country: (Northwest Africa) Mass:  4.76 kg | ||||||||||||
| Classification history: |
This is 1 of 21 approved meteorites classified as Chondrite-ung. [show all] Search for other: Ungrouped chondrites | ||||||||||||
| Comments: |
Approved 14 Jan 2008 Revised 4 Aug 2008: final writeup | ||||||||||||
| Writeup |
Writeup from MB 93:
Northwest Africa 2994 Northwest Africa Find: 2007 Chondrite (ungrouped) History and physical characteristics: A 4756 g unbrecciated, complete stone was purchased in Morocco in July 2007. This greenish stone is desert-polished to a high degree with only patches of semi-polished black fusion crust. Large, dark green olivine and orthopyroxene porphyroblasts on the surface range in size from a few to 38 mm. One centimeter-sized metal blob, together with minor metal enclaves of several millimeters, is also a prominent surface characteristic. Only minor iron oxide staining is present as a chemical weathering signature, and alteration veining is not evident. Petrography (T. Bunch and J. Wittke, NAU; A. Irving, UWS): A remarkable, recrystallized stone with textures that range from porphyroblastic to poikiloblastic. Grain boundaries are irregular with few 120º triple junctions. Both olivine poikiloblasts (with orthopyroxene and opaque inclusions) and orthopyroxene poikiloblasts (with olivine inclusions) are common. Grain size, exclusive of porphyroblasts, is 0.1 to 1.6 mm in largest dimension. Scarce, highly modified relict chondrule fragments (2 per 1.6 mm2) are present and are evident only as patches of recrystallized barred olivine and felsic mesostasis (one example has an annular olivine ring). SEM-BSE integrated gray-scale modal analyses, in vol%: olivine = 45; orthopyroxene = 42; augite = 3; plagioclase = 3; FeS = 3; chromite = 2 and metal = 2 with a trace amount of merrillite. Mineral compositions: Olivine (Fa37.3; FeO/MnO = 81-88), orthopyroxene (Fs29.5Wo3.1; FeO/MnO = 53-58), augite (Fs12.1Wo45.7), plagioclase (An53.3Or0.8; FeO = 0.38 wt%); chromite (cr# = 71; TiO2 = 1.91, MgO = [both 2.66 wt%]), kamacite (Ni = 6.0 wt%) and taenite (Ni = 25.6 wt%). Oxygen isotopes: (D. Rumble, CIW) Replicate analyses of acid-washed material by laser fluorination gave, respectively: d17O= -0.007 ; +0.078; d18O = 3.331 ; 3.355, D17O = -1.6769 ; -1.687 (all ‰). Classification: Chondrite (Ungrouped); S1, minor weathering. Type specimen: A total of 23 g is on deposit at NAU. The main mass holder is anonymous.
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| Data from: MB93 Table 2 Line 11: |
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| Plots: | O isotopes: | ||||||||||||
| Institutions and collections |
NAU: Geology, Bldg 12
Knoles Dr
Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012) 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) |
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| Catalogs: |
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| References: | Published in Meteoritical Bulletin, no. 93, MAPS 43, 571-632 (2008)
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| Geography: |
Statistics: This is 1 of 9305 approved meteorites from (Northwest Africa) (plus 1873 unapproved names) | ||||||||||||