^1,2Andrew Glikson, ³Arthur Hickman, ⁴Noreen J. Evans, ^4,5Christopher L. Kirkland, ^7,8Jung-Woo Park, ⁷Robert Rapp, ^3,6Sandra Romano
¹Geoscience Australia, P.O. Box 378, Canberra, A.C.T. 2601, Australia
²Planetary Science Institute, Australian National University, Acton, Australian Capital Territory, Australia
³Geological Survey of Western Australia, 100 Plain Street, East Perth, W.A. 6004, Australia
⁴Applied Geology, John de Laeter Centre, TIGeR, Curtin University, Bentley, WA 6102, Australia
⁵Centre for Exploration Targeting, Curtin Node, Department of Applied Geology, Western Australian School of Mines, Curtin University, WA 6102, Australia
⁶Centre for Exploration Targeting, School of Earth and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, W.A. 6004, Australia
⁷Research School of Earth Sciences, Australian National University, Acton, Canberra 2601, Australia
⁸School of Earth and Environmental Sciences & Research Institute of Oceanography, Seoul National University, Seoul 151-747, South Korea

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Reference
Glikson A, Hickman A,Evans NJ, Kirkland CL, Park J-W, Rapp R, Romano S (2016) A new ∼3.46 Ga asteroid impact ejecta unit at Marble Bar, Pilbara Craton, Western Australia: A petrological, microprobe and laser ablation ICPMS study. Precambrian Research 279, 103–122
Link to Article [doi:10.1016/j.precamres.2016.04.003]

¹Shaolin Li, ^1,2Weibiao Hsu, ³Yunbin Guan, ⁴Linyan Wang, ¹Ying Wang
¹Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, China
²Institute of Space Sciences, Macau University of Science and Technology, Macau, China
³Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
⁴Faculty of Earth Sciences, China University of Geosciences, Wuhan, China

Northwest Africa (NWA) 4898 is the only low-Ti, high-Al basaltic lunar meteorite yet recognized. It predominantly consists of pyroxene (53.8 vol%) and plagioclase (38.6 vol%). Pyroxene has a wide range of compositions (En12–62Fs25–62Wo11–36), which display a continuous trend from Mg-rich cores toward Ca-rich mantles and then to Fe-rich rims. Plagioclase has relatively restricted compositions (An87–96Or0–1Ab4–13), and was transformed to maskelynite. The REE zoning of all silicate minerals was not significantly modified by shock metamorphism and weathering. Relatively large (up to 1 mm) olivine phenocrysts have homogenous inner parts with Fo ~74 and sharply decrease to 64 within the thin out rims (~30 μm in width). Four types of inclusions with a variety of textures and modal mineralogy were identified in olivine phenocrysts. The contrasting morphologies of these inclusions and the chemical zoning of olivine phenocrysts suggest NWA 4898 underwent at least two stages of crystallization. The aluminous chromite in NWA 4898 reveals that its high alumina character was inherited from the parental magma, rather than by fractional crystallization. The mineral chemistry and major element compositions of NWA 4898 are different from those of 12038 and Luna 16 basalts, but resemble those of Apollo 14 high-Al basalts. However, the trace element compositions demonstrate that NWA 4898 and Apollo 14 high-Al basalts could not have been derived from the same mantle source. REE compositions of its parental magma indicate that NWA 4898 probably originated from a unique depleted mantle source that has not been sampled yet. Unlike Apollo 14 high-Al basalts, which assimilated KREEPy materials during their formation, NWA 4898 could have formed by closed-system fractional crystallization.

Reference
Li S, Hsu W, Guan Y, Wang L, Wang Y (2016) Petrogenesis of the Northwest Africa 4898 high-Al mare basalt. Meteoritics & Planetary Science (in Press)
Link to Article [DOI: 10.1111/maps.12663]
Published by arrangement with John Wiley and Sons