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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 billion 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".〔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 (abstract )〕 ==See also== * Glossary of meteoritics * List of lunar meteorites 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sayh al Uhaymir 169」の詳細全文を読む スポンサード リンク
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