Official Meteoritical Bulletin entry for Northwest Africa 4472:
Northwest Africa 4472 Algeria Find: July 2006 Achondrite (lunar, KREEP-rich breccia)
History: G. Hupé purchased the sample July 2006 from a dealer in Tagounite, Morocco. Physical characteristics: A single 64.3 g stone with visible pale gray to whitish clasts in a dark gray matrix. Fusion crust is not evident, but the exterior has fractures and thin coatings of desert varnish on exposed surfaces. Petrography: (A. Irving and S. Kuehner, UWS) Lithic clasts (up to 0.65 cm) are predominantly various types of ophitic to quench-textured basalts (composed of pyroxene(s), plagioclase, olivine, ilmenite, and rare baddeleyite). Granophyre clasts (consisting of “ribbon-like” subparallel intergrowths of silica and K-feldspar with accessory baddeleyite and rare tranquillityite) are present as a minor component, as well as clasts composed mainly of fayalite (with associated glass, silica, K-feldspar, and merrillite) and spherical to ellipsoidal glass objects (up to 60 µm across). Mineral clasts include pyroxenes, olivine, plagioclase, silica, zircon, baddeleyite, merrillite, Ti-chromite, fayalite, ilmenite (with baddeleyite inclusions), metal (both kamacite and taenite), troilite, and schreibersite (Kuehner et al. 2007). Mineral compositions and geochemistry: Olivine (Fa56.6–64.6; FeO/MnO = 91–101), plagioclase (An86.9–97.5 Or0.2–0.6), orthopyroxene (Fs26.9–29.3Wo3.8–4.1; FeO/MnO = 51–62), subcalcic augite (Fs52.6Wo30.5; FeO/MnO = 72), Al-Cr-rich pigeonite (Fs27.0Wo17.1; FeO/MnO = 51.1, Al = 3.10 wt%, Cr = 1.01 wt%), fayalite (Fa90.3; FeO/MnO = 92), barian K-feldspar intergrown with silica (Or80.9–55.6Ab15.3–30.2 Cn0.6–6.3). Bulk composition: (R. Korotev, WUSL) INAA on nine ~30 mg subsamples gave a mean composition of: Na = 0.448, Fe = 7.14 (both wt%), Sc = 20.9, La = 44.7, Sm = 19.51, Eu = 1.50, Yb = 13.4, Zr = 438, Hf = 11.1, Ba = 601, Th = 7.49 (all ppm). Although it is possible that there is a minor mare basalt component, this specimen is dominated by materials with KREEP-like compositions and is essentially identical in bulk composition and petrologic characteristics to Northwest Africa 4472. Classification: Achondrite (lunar, KREEP-rich breccia). Type specimen: A total of 12.87 g and 3 polished thick slices are on deposit at UWS. G. Hupé holds the main mass.
Scientific abstracts and news regarding NWA 4472:
Joy K.H., Burgess R., Hinton R.,Fernandes V.A. , Crawford I.A., Kearsley A.T.,and Irving A.J.
(2011) Petrogenesis and chronology of lunar meteorite Northwest Africa 4472:
A KREEPy regolith breccia from the Moon. Geochimica et Cosmochimica Acta75, 2420-2452.
Arai T., Yoshitake M., Tomiyama T., Niihara T., Yokoyama T., Kaiden H., Misawa K., and Irving A. J.
(2010) Support for a prolonged KREEP magmatism: U-Pb age dating of zircon and baddeleyite in lunar meteorite NWA 4485 meteorites (abstract). In Lunar and Planetary Science XLI, abstract no. 2379,
41st Lunar and Planetary Science Conference, Houston. http://www.lpi.usra.edu/meetings/lpsc2010/pdf/2379.pdf
Arai T. Misawa K. Tomiyama T. Yoshitake M. Irving A. J.
(2009) Constraints on lunar KREEP magmatism: A variety of KREEP basalt derivatives in lunar meteorite NWA 4485 (abstract).
In Lunar and Planetary Science XL, abstract no. 2292,
40th Lunar and Planetary Science Conference, Houston. http://www.lpi.usra.edu/meetings/lpsc2009/pdf/2292.pdf
Joy K. H., Burgess R., Hinton R., Fernandes V. A., Crawford I. A., Kearsley A. T., Irving A. J., and EIMF Team
(2009) U-Pb and Ar-Ar chronology of lunar meteorite Northwest Africa 4472 (abstract).
In Lunar and Planetary Science XL, abstract no. 1708,
40th Lunar and Planetary Science Conference, Houston. http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1708.pdf
Joy K. H., Crawford I. A., Kearsley A. T., Fernandes V. A., Burgess R., and Irving A. J.
(2008) The petrography and composition of lunar meteorite Northwest Africa 4472 (abstract).
In Lunar and Planetary Science XXXIX, abstract no. 1132,
39th Lunar and Planetary Science Conference, Houston. http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1132.pdf
Joy K. H., Fernandes V. A., Burgess R., Crawford I. A., Irving A. J., Kearsley A.T.
(2007) The clast inventory of KREEPy lunar meteorite North West Africa 4472 (abstract).
70th Annual Meeting of the Meteoritical Society, abstract no. 5223.
Lunar and Planetary Institute, Houston. http://www.lpi.usra.edu/meetings/metsoc2007/pdf/5223.pdf
Kuehner S. M., Irving A. J., Korotev R. L., Hupé G. M., and Ralew S.
(2007) Zircon-baddeleyite-bearing silica+K-feldspar granophyric clasts in
KREEPrich lunar breccias Northwest Africa 4472 and 4485 (abstract).
In Lunar and Planetary Science XXXVIII, abstract no. 1516,
38th Lunar and Planetary Science Conference, Houston. http://www.lpi.usra.edu/meetings/lpsc2007/pdf/1516.pdf
Complete polished slice of NWA 4472.
35.3g main mass of NWA 4472.
“Granophyric” clast composed of ribbon-like intergrowth of silica (blue) and K-feldspar (green).
“Granophyric” intergrowth clasts (blue and green), pyroxene (red) and troilite+metal (white).
“Granophyric” intergrowth clast (blue and green).
Fayalite-rich clast (yellow) associated with silica+K-feldspar intergrowth, troilite, merrillite, pigeonite and glass.
Small glass sphere, probably impact melt droplet (diagonal line are polishing scratches).
Glassy clast with fine quench crystals.
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