Sayh al Uhaymir 169

Lunar Meteorite: Sayh al Uhaymir* 169

Oman

* "slightly reddish plain" (Thanks for the better translation, Ali.)

Sayh al Uhaymir 169 in the desert. (Photo courtesy of Beda Hofmann)

Sawn face of Sayh al Uhaymir 169. The lighter, bottom portion is the impact-melt lithology,
the top is the regolith breccia lithology. (Photo courtesy of Natural History Museum Bern/Beda Hofmann)

Close-up of regolith breccia lithology on another sawn face.
(Photo courtesy of Natural History Museum Bern/Peter Vollenweider)

Interface of impact-melt-breccia lithology (left) and regolith-breccia lithology (right).
(Millimeter ticks in background at bottom. Photo by Randy Korotev)

from The Meteoritical Bulletin, no. 87, Meteoritics & Planetary Science 38, A189-A248 (2003)

Oman
Found 2002 January 16

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

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 ortopyroxene clasts are present. The fine-grained impact melt matrix consists mainly of short prismatic low-Ca pyroxene (En_61-64,Wo_2-4), interstitial plagioclase (An_75-81) intergrown with potassium feldspar. The remaining minerals are poicilitic ilmenite, whitlockite, olivine (Fo_{58- 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 KREEPeriched lithology among all known lunar rocks. Weathering: W1 (Fe metal shows only little oxidation). Specimens: All in NMB.

More Information

Meteoritical Bulletin Database

SaU 169

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 chemistry. Meteoritics & 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 169 (abstract). 69th Annual Meeting of the Meteoritical Society, abstract no. 5098. Lunar and Planetary Institute, Houston.

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

Cohen B. A. (2005) More impact-melt clasts in feldspathic lunar meteorites (abstract). 68th Annual Meeting of the Meteoritical Society, number 5314.

Cohen B. A. (2008) Lunar meteorite impact melt clasts and lessons learned for lunar surface sampling (abstract). In Lunar and Planetary Science XXXIX, abstract no. 2532, 39th Lunar and Planetary Science Conference, Houston.

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, no. 5066 (abstr.).

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 Moon. Science 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 (abstract). 69th Annual Meeting of the Meteoritical Society, abstract no. 5111. Lunar and Planetary Institute, Houston.

Korotev R. L. (2004) A unique chunk of the Moon. Science 305, 622–623.

Korotev R. L. (2005) Lunar geochemistry as told by lunar meteorites. Chemie der Erde 65, 297–346.

Korotev R. L. and Zeigler R. A. (2007) Keeping up with the lunar meteorites (abstract). In Lunar and Planetary Science XXXVIII, abstract no. 1340, Lunar and Planetary Institute, Houston.

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.

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, no. 5037 (abstr.).

Lorenzetti S., Busemann H., and Eugster O. (2005) Regolith history of lunar meteorites. Meteor. Planet. Sci. 40, 315-327.

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 (abstract). 69th Annual Meeting of the Meteoritical Society, abstract no. 5036. Lunar and Planetary Institute, Houston.

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 169 (abstract). Lunar and Planetary Science XXVII, abstract no. 2366, Lunar and Planetray Institute, Houston.

Chemical Classification

Overview | SaU 169

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Prepared by:

Randy L. Korotev

Department of Earth and Planetary Sciences
Washington University in St. Louis

Please don't contact me about the meteorite you think you’ve found until you read this and this.

e-mail: korotev@wustl.edu

Last revised: 07-Apr-2008