Lunar Meteorite: Larkman Nunatak 06638

Larkman Nunatak 06638 in the field (5 g). Photo credit: NASA/JSC
LAR 06638 in the NASA-JSC curatorial lab. Photo credit: NASA/JSC. 1-cm cube.
Small samples of LAR 06638. Millimeter ticks for scale. Photo credit: Randy Korotev
Back-scattered electron image (gray-scale) and a red-green-blue elemental x-ray map of a thin section of LAR 06638. In BSE images, brightness increases with mean atomic mass. The darkest areas are rich in plagioclase (Al) and the lightest areas are rich in mafic (Fe-bearing) minerals. In the X-ray map, areas rich in Al (e.g., plagioclase) are bright red, areas rich in Mg are bright green (e.g., olivine), and areas rich in Fe (e.g., pyroxene or FeNi metal) are bright blue. Notice that there are three different layers of glass coating, not all of which may be fusion crust in that the two inner ones have different compositions. The scale bar applies to the BSE image. Image credit: Ryan Zeigler
Listed in The Meteoritical Bulletin, No. 94

Classification from Antarctic Meteorite Newsletter, Vol. 30, No. 2, 2007

Larkman Nunatak 06638 (LAR 06638)

Location: Larkman Nunatak, Transantarctic Mountains, Antarctica
Field No.: 19362
Dimensions (cm): 2.5 x 2.0 x 0.75
Mass: 5.293 g

Classification: Lunar-Anorthositic Breccia

Macroscopic Description: Kathleen McBride The bottom exterior surface has black fusion crust, while the top has a lighter brown crust. Polygonal fractures are present. The gray and white matrix has a sharp line where matrix becomes black with white inclusions.

Thin Section (,2) Description: Tim McCoy, Lauren LaCroix and Linda Welzenbach. The section shows a groundmass of comminuted pyroxene, olivine and plagioclase with grain sizes up to 1 mm. Clasts up to 2 mm include basalts, granulites and anorthosites. One-half of the section exhibits a darkened matrix. Olivine is Fa28-33, pyroxene ranges from Fs27-39Wo3-12 (Fe/Mn ~ 60), and plagioclase An93-98. The meteorite is lunar, probably an anorthositic regolith breccia.

Randy Says…

Compositionally, LAR 06638 is a typical feldspathic lunar meteorite.

More Information

Meteoritical Bulletin Database

LAR 06638


ANSMET Location Map


Korotev R. L. and Zeigler R. A. (2014) Chapter 6. ANSMET Meteorites from the Moon, Thirty-five Seasons of U.S. Antarctic Meteorites (1976–2010): A Pictorial Guide to the Collection (editors K. Righter, R. P. Harvey, C. M. Corrigan, and T. J. McCoy), 101–130, Special Publications 68, American Geophysical Union, Washington, D. C., 296 pages, ISBN: 978-1-118-79832-4.

Korotev R. L., Irving A. J., and Bunch T. E. (2008) Keeping up with the lunar meteorites – 2008Lunar and Planetary Science XXXIX, abstract no. 1209.

Korotev R. L., Jolliff B. L., and Zeigler R. A. (2010) On the origin of the moon’s feldspathic highlands, pure anorthosite, and the feldspathic lunar meteorites41st Lunar and Planetary Science Conference, abstract no. 1440.

Zeigler R. A. and Korotev R. L. (2013) Petrography and geochemistry of feldspathic lunar meteorite Larkman Nunatak 0663844th Lunar and Planetary Science Conference, abstract no. 1767.