Lunar hematite holds clues

Abstract

Planetary Science The poles of the Moon may contain a record of billions of years of oxygen isotopes of Earth's atmosphere. The lunar surface is highly reducing, yet a recent study using data collected by the Moon Mineralogy Mapper provides strong evidence for the presence of hematite, a common iron oxidation product on Earth, at high lunar latitudes. Li et al. mapped the hematite deposits, noting that they are mostly found in association with east equator–facing sides of topographic highs on the lunar nearside of the Moon. They propose that oxygen, delivered from Earth's upper atmosphere, could produce a locally oxidizing environment, allowing hematite to form. Sci. Adv. 10.1126/sciadv.aba1940 (2020).