Sayh al Uhaymir 169 (SaU 169) is a 206 gram lunar meteorite found in the Sayh al Uhaymir region of the Sultanate of Oman in January 2002.

Sayh al Uhaymir 169
Complete stone of SaU169 showing the fusion crust and also a large clast
ClassLunar meteorite
GroupImpact breccia
Composition45.15% SiO2, 15.88% Al2O3, 11.09% MgO, 10.67% FeO, 10.16% CaO, 2.21% TiO2, 1.14% P2O5, 0.98% Na2O, 0.54% K2O, 0.33% S, 0.14% MnO
RegionSayh al Uhaymir
Coordinates20°34′24″N 57°19′24″E / 20.5733°N 57.3234°E / 20.5733; 57.3234
Observed fallNo
Fall date< 9700 years ago
Found date16 January 2002
TKW206.45 grams (7.282 oz)
Alternative namesSaU 169
Sayh al Uhaymir 169 as found in the Oman desert

This stone is an impact-melt breccia with exceedingly high concentrations of thorium and other incompatible elements; phosphorus, rare-earth elements, and the three most important naturally occurring radioactive elements, potassium, thorium, and uranium, have been segregated in the liquid phase when the lunar minerals crystallized. The impact that eventually sent this stone to the Earth is dated at 3.9 billion years and could be the Imbrium impact. It collided with the Earth less than 9,700 years ago.

It is complete, a light gray-greenish rounded stone, dimensions 70 mm × 43 mm × 40 mm (2.8 in × 1.7 in × 1.6 in) and mass 206 grams (7.3 oz), found on January 16, 2002, in the central desert of Oman at 20° 34.391' N and 57° 19.400' E.

According to geologist Edwin Gnos and coworkers, the meteorite's origin can be pinpointed to the vicinity of the Lalande impact crater; isotopic analysis shows a complex history of four distinct lunar impacts: "Crystallization of the impact melt occurred at 3909 ± 13 Ma, followed by exhumation by a second impact at 2800 Ma, which raised the sample to a regolith position at unconstrained depth. A third impact at 200 Ma moved the material closer to the lunar surface, where it mixed with solar-wind–containing regolith. It was launched into space by a fourth impact at <0.34 Ma".[1]

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  1. ^ Gnos, Edwin, et al., 2004, Pinpointing the Source of a Lunar Meteorite: Implications for the Evolution of the Moon, Science 30 July 2004: Vol. 305 no. 5684 pp. 657–659. doi:10.1126/science.1099397.