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Northwest Africa 4864 | |||||||||||||||||||||||
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Basic information | Name: Northwest Africa 4864 This is an OFFICIAL meteorite name. Abbreviation: NWA 4864 Observed fall: No Year found: 2007 Country: (Northwest Africa) Mass: 94 g | ||||||||||||||||||||||
Classification history: |
This is 1 of 329 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite). [show all] Search for other: Martian meteorites | ||||||||||||||||||||||
Comments: |
Approved 16 Dec 2008 Revised 23 Feb 2012: Erratum on O isotopes | ||||||||||||||||||||||
Writeup |
Writeup from MB 94:
Northwest Africa 4864 Northwest Africa Find: 2007 Achondrite (Martian, basaltic shergottite) History: On July 16, 2007, a person brought 10 pieces totaling 94 g to the Institut für Planetologie (Münster) for classification. Physical characteristics and petrography: (A. Bischoff, Mun) The rock is slightly weathered and relatively coarse-grained. The main constituents, pyroxene and maskelynite, have sizes up to 2 mm (Fig. 1). Near equal abundances of these phases are estimated. In some pyroxenes, glassy melt veins and pockets are visible. Minor phases include ilmenite, Fe-sulfide, and phosphate. Mineral compositions and geochemistry: The mean composition of pyroxene is Fs50 ± 5; Wo13 ± 2. Maskelynite An51 ± 3. Oxygen isotopes (A. Pack and A. Suessenberger, University of Göttingen) revealed: 1st analysis: δ18O = + 5.3 ± .25‰, δ17O = +3.5 ± 0.15‰, Δ17O = +0.31 ± 0.03‰, 2nd analysis: δ18O = +5.1 ± 0.25‰, δ17O = +3.4 ± 0.15‰, Δ17O = +0.33 ± 0.03‰. Classification: Achondrite (Martian, basaltic shergottite) Type specimens: 19 g and one polished thin section is on deposit at Mun. An anonymous collector holds the main mass. Writeup from MB 100: Northwest Africa 4864, Correction The values for δ17O shown in Meteoritical Bulletin 94 were reported incorrectly. The correct oxygen isotopic composition is: δ18O = + 5.3 ± .25‰, δ17O = +3.1 ± 0.15‰, Δ17O = +0.31 ± 0.03‰, 2nd analysis: δ18O = +5.1 ± 0.25‰, δ17O = +3.0 ± 0.15‰, Δ17O = +0.33 ± 0.03‰. | ||||||||||||||||||||||
Data from: MB94 Table 2 Line 75: |
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Plots: | O isotopes: | ||||||||||||||||||||||
Institutions and collections |
Mun: Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany (institutional address; updated 23 Jan 2012) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 94, MAPS 43, 1551-1588 (2008) Published in Meteoritical Bulletin, no. 100, MAPS 49, E1-E101 (2014)
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Geography: |
Statistics: This is 1 of 9914 approved meteorites from (Northwest Africa) (plus 1841 unapproved names) |