¹Haijun Cao,^1,2Zongcheng Ling,¹Jian Chen,^1,2,3Xiaohui Fu,⁴Yongliao Zou
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13741]
¹Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai, Shandong, 264209 China
²CAS Center for Excellence in Comparative Planetology, Chinese Academy of Sciences, Hefei, China
³State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Taipa, Macau, China
⁴State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, 100190 China
Published by arrangement with John Wiley & Sons

Lunar meteorite Northwest Africa (NWA) 11460 has been classified as a polymict breccia, composed of feldspathic clasts, mafic-rich clasts (gabbroic and troctolitic fragments), granulites, and a wide range of impact melt breccias and dimict breccias. The non-mare clasts have chemical affinities in major element composition to the Apollo ferroan anorthosites (FAN) and magnesian-suite plutonic rocks. In contrast, incompatible trace element (ITE) compositions of the Mg-richer clasts are more consistent with those of FANs rather than magnesian-suite rocks. NWA 11460 has a Mg-rich feldspathic bulk composition (FeO = 4.53 wt%, Al2O3 = 25.87 wt%, and Mg# = 73.8) and relatively ITE-poor (i.e., Th = 0.31 ppm and Sm = 0.65 ppm) characteristics. Feldspathic impact melt materials are approximately similar in composition to the estimated composition for the upper feldspathic lunar crust (as defined by Korotev et al., 2003). The ITE-poor and Mg-rich characteristics different from Apollo 16 feldspathic impact melts indicate that this meteorite has been possibly derived from a region distal to the nearside lunar highlands. Our analysis further suggests that NWA 11460 most likely originated from the farside of the Moon. Compositionally, Mg-rich ITE-poor clasts within NWA 11460 as well as those observed in other feldspathic lunar meteorites (which probably came from many different lunar regions) reveal that Mg-rich rocks with low-ITE components represent an important constituent of lunar crustal rocks. The diversities of highly magnesian non-mare clasts and the low-ITE chemistry provide geochemical clues for the genetic relationship between KREEP components and magnesian plutonic magmatism on the lunar farside.