Iron valences of plagioclase in lunar samples by synchrotron XANES

Abstract

We measured Fe valence in plagioclase from 13 lunar rocks (9 Apollo, 1 Luna and 3 lunar meteorites) by synchrotron Fe-XANES to see the relationship between redox states and water contents. Plagioclase in HT and KREEP basalts shows lower Fe³⁺ ratios compared to LT and VLT basalts, which is related to the water content. On the other hand, plagioclase in highland rocks (FAN and MAN) have high Fe³⁺ ratios despite small water contents, suggesting the presence of oxidant other than water.