Lunar Meteorite: Sayh al Uhaymir 169

Sayh al Uhaymir 169 (206 g) in the desert. Photo credit: Beda Hofmann
Inside of SaU 169 with 5-cm scale bar. Photo credit: Natural History Museum Bern/Peter Vollenweider
Another slice of SaU 169, with regolith breccia (top) and impact-melt breccia (bottom). Photo credit: Natural History Museum Bern/Peter Vollenweider
Close-up of regolith breccia lithology. Photo credit: Natural History Museum Bern/Peter Vollenweider
Another slice of SaU 169, with a centimeter-sized norite (?) clast. Photo credit: Natural History Museum Bern/Peter Vollenweider
Lab sample of SaU 169 showing the sharp boundary between the impact-melt breccia (left) and the regolith breccia (right). Photo credit: Randy Korotev

from The Meteoritical Bulletin, No. 87

Sayh al Uhaymir 169 (SaU 169)

Oman
Found: 2002 January 16
Mass: 206.45 g  (1 piece)

Lunar meteorite (KREEP-rich mafic impact melt breccia and adhering regolith) 

History: A complete, light grey-greenish rounded stone (70 x 43 x 40 mm) weighing 206.45 g was found in the Sayh al Uhaymir region of Oman.

Finders, mineralogy and classification: E. Gnos, B. A. Hofmann and A. Al-Kathiri (UniBern): Dark brown fusion crust is only locally preserved. The impact melt breccia (87 vol% of the stone, based on 8 X-ray tomographic sections) contains 25-40 vol% of strongly shocked magmatic rocks and crystal clasts (up to 17 mm) derived from norites, evolved magmatites, and granulites set in a fine-grained (<0.1 mm) crystalline matrix. Most crystal fragments are shocked plagioclases, locally associated with enstatite. In addition to plagioclase metallic iron, spinel, olivine, and orthopyroxene clasts are present. The fine-grained impact melt matrix consists mainly of short prismatic low-Ca pyroxene (En61-64,Wo2-4), interstitial plagioclase (An75-81) intergrown with potassium feldspar. The remaining minerals are poikilitic ilmenite, whitlockite, olivine (Fo58- 59), zircon, and traces of troilite, kamacite and tridymite. The regolith (13 vol.%) present one one side of the meteorite comprises crystalline and glassy volcanic rocks, magmatic lithic fragments, breccia fragments, fragments of mafic granulites, and crystal fragments. The impact melt breccia contains 32 ppm Th and 8.5 ppm U, 0.47% K (K/U= 553), indicating a lunar origin. This is further confirmed by fusion-crust Fe/Mn of 75.1 (microprobe, n=14) and impact melt bulk Fe/Mn of 79. Oxygen isotope composition (I. A. Franchi, OU) are also consistent with a lunar origin (∆17O = 0.001 ± 0.032‰). This impact melt breccia is the most strongly KREEP enriched lithology among all known lunar rocks. Weathering: W1 (Fe metal shows only little oxidation).

Specimens: All in NMB.

Randy Says…

SaU 169 unique.

The impact-melt lithology has the greatest concentrations of geochemically incompatible elements (K, P, Zr, REE, Th, U, etc.) of any lunar meteorite or any other kind of meteorite. Concentrations of incompatible elements are very high even compared to most Apollo samples. It is, however, compositionally indistinguishable from one type of impact-melt breccia from Apollo 12.

The meteorite is the first for which the concentrations of naturally occurring thorium and uranium are so high that the radioactivity of the rock can be detected on a laboratory radiation survey meter (“Geiger counter”). [So as not to be too sensational, the radioactivity of most terrestrial granites and some other kinds of Earth rocks can also be detected with a radiation survey meter. Meteorites in general have less radioactivity than most Earth rocks.]

It is an unusual dilithologic meteorite (two main rock types in one rock).

It is the first lunar meteorite that must originate from the nearside feature known as the Procellarum KREEP Terrane.

More Information

Meteoritical Bulletin Database

Sayh al Uhaymir 169

Map

Schematic Map of  Find Locations of  Lunar Meteorite from Oman

References

Al-Kathiri A., Hofmann B. A., Jull A. J. T., and Gnos E. (2005) Weathering of meteorites from Oman: Correlation of chemical and mineralogical weathering proxies with 14C terrestrial ages and the influence of soil chemistryMeteoritics & Planetary Science 40, 1215-1239.

Al-Kathiri A., Gnos E. and Hofmann B. A. (2006) The regolith portion of the lunar meteorite Sayh al Uhaymir 16969th Annual Meeting of the Meteoritical Society, abstract no. 5098.

Al-Kathiri A., Gnos E. and Hofmann B. A. (2007) The regolith portion of the lunar meteorite Sayh al Uhaymir 169Meteoritics & Planetary Science 42, 2137-2152.

Cohen B. A. (2005) More impact-melt clasts in feldspathic lunar meteorites. 68th Annual Meeting of the Meteoritical Society, abstract no. 5314.

Cohen B. A. (2008) Lunar meteorite impact melt clasts and lessons learned for lunar surface samplingLunar and Planetary Science XXXIX, abstract no. 2532.

Day J. M. D, Elishevah M ., van Kooten M. E. , Hofmann B. A, and F. Moynier (2020) Mare basalt meteorites, magnesian-suite rocks and KREEP reveal loss of zinc during and after lunar formation. Earth and Planetary Science Letters, 531, Article 115998.

Fritz J. (2012) Impact ejection of lunar meteorites and the age of Giordano BrunoIcarus 221, 1183-1186.

Gnos E., Hofmann B. A., Al-Kathiri A., Lorenzetti S., Villa I., Eugster O., Jull A. J. T., Eikenberg J., Spettel B., Krähenbühl U., Franchi I. A., and Greenwood G. C. (2003) Lunar meteorite SaU 169; An extremely KREEP-rich rock. 66th Annual Meteoritical Society Meeting, abstract no. 5066.

Gnos E., Hofmann B. A., Al-Kathiri A., Lorenzetti S., Eugster O., Whitehouse M. J., Villa I., Jull A. J. T., Eikenberg J., Spettel B., Krähenbühl U., Franchi I. A., and Greenwood G. C. (2004) Pinpointing the source of a lunar meteorite: Implications for the evolution of the MoonScience 305, 657-659.

Gnos E., Hofmann B. A., Al-Kathiri A., and Whitehouse M. J. (2006) The KREEP-rich Imbrium impact melt breccia of the lunar meteorite Sayh al Uhaymir 169. 69th Annual Meeting of the Meteoritical Society, abstract no. 5111.

Korotev R. L. (2004) A unique chunk of the MoonScience 305, 622-623.

Korotev R. L. (2005) Lunar geochemistry as told by lunar meteoritesChemie der Erde 65, 297-346.

Korotev R. L. (2011) Lunar meteorites from Antarctica and Oman. 74th Annual Meeting of the Meteoritical Society, abstract no. 5073.

Korotev R. L. (2012) Lunar meteorites from OmanMeteoritics & Planetary Science 47, 1365-1402.

Korotev R. L. (2017) Update (2012–2017) on lunar meteorites from OmanMeteoritics & Planetary Science 52, 1251-1256.

All Korotev data on Omani lunar meteorites.

Korotev R. L. and Zeigler R. A. (2007) Keeping up with the lunar meteoritesLunar and Planetary Science XXXVIII, abstract no. 1340.

Korotev R. L, Zeigler R. A., Jolliff B. L., Irving A. J., and Bunch T. E. (2009) Compositional and lithological diversity among brecciated lunar meteorites of intermediate iron compositionMeteoritics & Planetary Science 44, 1287-1322.

Kramers J. D., Gnos E., Hofmann B. A., and al-Kathiri A. (2007) A ~4.3 Ga U-Pb age from lunar meteorite SaU169 and the chondritic Sm/Nd of the Moon. Goldschmidt Conference Abstracts 2007, A520.

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 KREEP-rich lunar breccias Northwest Africa 4472 and 4485Lunar and Planetary Science XXXVIII, abstract no. 1516.

Lin Y., Shen W., Liu Y., Xu L., Hofmann B. A., Mao Q., Tang G., Wu F., and Li X. (2010) Very high-K KREEP-rich clasts in the impact melt breccia of the lunar meteorite SaU 169 — Possible pristine urKREEP sample. 73rd Annual Meeting of the Meteoritical Society, abstract no. 5114.

Lin Y., Shen W., Liu Y., Xu L., Hofmann B. A., Mao Q., Tang G. Q., Wu F., and Li X. H. (2012) Very high-K KREEP-rich clasts in the impact melt breccia of the lunar meteorite SaU 169: New constraints on the last residue of the Lunar Magma OceanGeochimica et Cosmochimica Acta 85, 19-40.

Liu D., Wan Y., Zhang Y., Dong C., Jolliff B. L., Zeigler R. A., and Korotev R. L. (2009) Age of zircons in the impact-melt breccia in SaU 169 lunar meteorite: Beijing SHRIMP II study40th Lunar and Planetary Science Conference, abstract no. 2499.

Liu D., Jolliff B. L., Zeigler R. A., Wan Y., Zhang Y., Dong C., and Korotev R. L. (2010) A 3.91 billion year age for Apollo 12 high-thorium impact-melt breccias: Products of Imbrium, or an older impact basin in the Procellarum KREEP terrane? 41st Lunar and Planetary Science Conference, abstract no. 2477.

Liu D., Jolliff B. L., Zeigler R. A., Korotev R. L., Wan Y., Xie H., Zhang Y., Dong C., and Wang W. (2012) Comparative zircon U-Pb geochronology of impact melt breccias from Apollo 12 and lunar meteorite SaU 169, and implications for the age of the Imbrium impactEarth and Planetary Science Letters, 319-320, 277-286.

Lorenzetti S., Eugster O., Gnos E., Hofmann B. A., Al-Kathiri A., Villa I. and Jull A. J. T. (2003) Cosmic ray exposure history of the new Omani lunar meteorite Sayh al Uhaymir. 66th Annual Meteoritical Society Meeting, abstract no. 5037.

Lorenzetti S., Busemann H., and Eugster O. (2005) Regolith history of lunar meteoritesMeteoritics & Planetary Science 40, 315-327.

Nemchin, A. A., Long, T., Jolliff B. L., Wan Y., Snape J. F., Zeigler R., Grange M. L., Liu D., Whitehouse M. J., Timms N. E., and Jourdan F. (2021) Ages of lunar impact breccias: Limits for timing of the Imbrium impactGeochemistry 81, 125683.

Rankenburg K., Brandon A. D., and Neal C. R. (2006) Formation interval of the lunar mantle from high-precision Nd-isotope measurements of six lunar basalts. 69th Annual Meeting of the Meteoritical Society, abstract no. 5036.

Rankenburg K., Brandon A. D., and Neal C. R. (2006) Neodymium isotope evidence for a chondritic composition of the MoonScience 312, 1369-1372.

Tartese R., Anand M., Joy K. H., Franchi I. A. (2014) H and Cl isotope characteristics of apatite in brecciated lunar meteorites NWA 4472, NWA 773, SaU 169 and Kalahari 009. 77th Annual Meeting of the Meteoritical Society, abstract no. 5085.

Xing W. F., Hu S., Yang W., Zhang J. C., Hao J. L., Xiao L., and Lin Y. T. (2017) Microstructures and U-Pb chronology of zircons in the regolithic breccia of the lunar meteorite Sayh al Uhaymir 16980th Annual Meeting of the Meteoritical Society, abstract no. 6377.

Xu L., Lin Y. T., Hofmann B. A., Gnos E., and Ouyang Z. Y. (2012) The origin of metal particles in lunar meteorites75th Annual Meeting of the Meteoritical Society, abstract no. 5247.

Zeigler R. A., Korotev R. L., and Jolliff B. L. (2006) Geochemistry and petrography of high-Th, mafic impact-melt breccia from Apollo 12 and Sayh al Uhaymir 169Lunar and Planetary Science XXVII, abstract no. 2366.

Zeigler R. A., Jolliff B. L., Korotev R. L., and Carpenter P. K. (2008) Determination of Sr concentrations in lunar plagioclase by electron microprobe analysis. Goldschmidt Conference Abstracts 2008, Geochimica et Cosmochimica Acta 72, 12S, 1072.

Zhou Q., Zeigler R. A., Yin Q.-Z., Korotev R. L., Jolliff B. L., Amelin Y., Marti K., Wu F. Y., Li X. H., Li Q. L., Lin Y. T., Liu Y., and Tang G. Q. (2012) U-Pb dating of zircons and phosphates in lunar meteorites, acapulcoites and angrites43rd Lunar and Planetary Science Conference, abstract no. 1554..