Miyake-jima Anorthite: A Lunar Crustal Material Analog (Supplementary)

High calcic (~95% anorthite) plagioclase is the key mineral comprising the primary lunar crustal suites which covers over 60% of the Moon’s surface. Pristine crystals of similar high calcic plagioclase are rare occurrences on Earth, which creates a roadblock to using terrestrial material as lunar crustal analog. We discuss the potential of a particular megacrystic anorthite (An95.51 ± 0.31) occurring in the basaltic lava flows of island arc volcano in Miyake-jima, Japan to be treated as an analog material. A comprehensive analytical routine for the Miyake-jima anorthites has been performed to explore intra- and inter-crystalline heterogeneities in terms of major, minor and trace elements. These anorthites show flat concentration gradients across core to rim profiles for all major elements (Si, Al, Ca, Na) minor elements (Mg, Fe) and most trace elements (La, Ce, Pm, Nd, Eu). Comparing the chemical composition of the samples with that of different lunar crustal suites like ferroan anorthosites, high-magnesium suites and high alkali suites show that the Miyake-jima anorthites are overlapping or depleted in most minor and trace elements except for slight enrichment in Li, Ti, Fe, Sr, Eu, Ba, and Pb. The low abundance of most trace elements provide the opportunity to dope the anorthites with the elements of interest and explore their interaction with the An95 matrix. The lack of typical magmatic zoning and overlapping elemental compositions across the different megacrysts make the Miyake-jima anorthites very well-suited for studying lunar crustal spectra, mineralogy and petrology. Near and thermal infrared spectral measurements of the anorthites highlight the importance of developing chemically and mineralogically consistent terrestrial analogs for remote sensing studies.Supplementary Figures: S1 - S6 (Supplementary Figure S1. Reflected light images of Miyake-jima anorthite crystals; Supplementary Figure S2. Relative error of analyzed external reference material BCR-2G and BHVO-2G; Supplementary Figure S3. Concentration of copper (in ppm) measured using 63Cu and 65Cu isotopes for individual analyses; Supplementary Figure S4. Chondrite-normalized individual LREEs across profiles of crystals; Supplementary Figure S5. Measured Th concentrations (with 2-sigma standard errors) and all limits of detection (LOD) for analyses of Miyake-jima crystals; Supplementary Figure S6. Comparison between analytical techniques between electron microprobe, SIMS and LA-ICPMSfor (a)