¹Heng-Ci Tian,¹Wei Yang,¹Di Zhang,^1,3Huijuan Zhang,²Lihui Jia,²Shitou Wu,¹Yangting Lin,²Xianhua Li,²Fuyuan Wu
American Mineralogist 108, 1669-1677 Link to Article [http://www.minsocam.org/msa/ammin/toc/2023/Abstracts/AM108P1669.pdf]
¹Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
²State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
³School of Earth Sciences, East China University of Technology, Nanchang 330013, Jiangxi, China
Copyright: The Mineralogical Society of America

This study focuses on using the chemical compositions of plagioclase to further investigate the
petrogenesis of Chang’E-5 young mare basalts and constrain its parental melt composition. Together
with previously published data, our results show that the plagioclase in mare basalts overall displays
large variations in major and trace element concentrations. Inversion of the plagioclase data indicates
that the melt compositions parental to Chang’E-5 basalts have high rare earth elements (REE) concentrations similar to the high-K KREEP rocks (potassium, rare earth elements, and phosphorus). Such a signature is unlikely to result from the assimilation of KREEP components, because the estimated
melt Sr shows positive correlations with other trace elements (e.g., Ba, La), which are far from the
KREEP end-member. Instead, the nearly parallel REE distributions and a high degree of trace element
enrichment in plagioclase indicate an extensive fractional crystallization process. Furthermore, the
estimated melt REE concentrations from plagioclase are slightly higher than those from clinopyroxene,
consistent with its relatively later crystallization. Using the Ti partition coefficient between plagioclase
and melt, we estimated the parental melt TiO2 content from the earliest crystallized plagioclase to be
~3.3 ± 0.4 wt%, thus providing robust evidence for a low-Ti and non-KREEP origin for the Chang’E-5
young basalts in the Procellarum KREEP terrane.