Sayh al Uhaymir 169
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Sayh al Uhaymir 169 (SaU 169) is a 206g lunar meteorite found in the Sayh al Uhaymir region of the Sultanate of Oman in January 2002.
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 million years and could be the Imbrium impact. It collided with the Earth 9.7 ± 1.3 kya.
It is complete, a light gray-greenish rounded stone, dimensions 70x43x40mm and mass 206 grams, 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" (Science 2004, vol 305, pp657-9, July 2004).
