Experimental Data on the Formation of Nanophase Iron in the Lunar Soil

Abstract

The formation of nanophase metallic iron (npFe⁰) in lunar regoliths, which is observed in the condensate films on the surface of mineral grains and in agglutinate glasses, is one of the signs of “space weathering” on the Moon under the influence of solar wind and micrometeorite bombardment. The paper presents the results of laser experiments simulating micrometeorite “impact” on basalt, olivine, pyroxene and some other types of targets. Numerous iron nanospherules that are often arranged into chains and clusters were found in the molten products of the “impact.” The experiments showed that npFe⁰ can be formed without the participation of implanted solar wind ions (hydrogen ions) as a reducing agent, as well as without iron condensation from shock-formed vapor. Similar clusters of nanophase metallic iron and chain structures are observed in the impact glasses of the lunar regolith and asteroid particles.