doi:

DOI: 10.3724/SP.J.1084.2013.00315

Chinese Journal of Polar Research (极地研究) 2013/25:4 PP.315-328

LUNAR METEORITES: WITNESSES TO THE MOON'S COMPOSITION AND EVOLUTION


Abstract:
Lunar meteorites are rock samples from the Moon that have experienced a shock event resulting from impact by an asteroid that results in the ejection of the rock from the Moon's surface and its landing on Earth. Since the first lunar meteorite (ALHA 81005) was discovered and identified in 1979, a total of 165 lunar meteorites have been found. Additionally, the Apollo and Luna projects returned 382 kg of lunar samples; however, according to the collection sites are limited, lunar meteorites still provide important supplementary information on the composition and evolutionary history of the Moon. Except for a small amount of unbrecciated crystalline rocks, the majority of lunar meteorites are breccias that consist mainly of highland anorthositic breccias, mare basaltic breccias and mingled breccias. Petrographic analyses of clasts within lunar meteorites show that they contain a wide variety of rocks including anorthosites, basalts, gabbros, troctolites, norites and KREEP rocks. More and more KREEP components are found in lunar meteorites. For example, the VHK KREEP clasts in meteorite SaU 169 may represent the urKREEP magma; such KREEP components provide important information on the origin of the KREEP. Research has identified six launching pairs and nine possible launching sites on the Moon. The discovery of the lunar symplectites also provides evidence for shock metamorphism on the lunar surface. Furthermore, the isotopic ages and the composition of noble gases not only provide important information on the process of crystallization of lunar rocks and the formation of lunar crust, but also give insight into the history of shock events on the lunar surface.

Key words:Lunar meteorites, KREEP rocks, KREEP, launching pair, launching sites

ReleaseDate:2014-07-21 16:59:36



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