Experimental Model of the Formation of Nanophase Metallic Iron in the Lunar Regolith

Abstract One of the signs of “space weathering” on the Moon, including the effect of the solar wind and micrometeorite bombardment, is the formation of nanophase metallic iron (np-Fe0) in the lunar regolith, which is observed in condensate films on the surface of regolith mineral grains and in agglutinate glasses. The results of pulsed laser experiments simulating a micrometeorite “impact” on a basalt target are reported. Iron nanoglobules structured into chains and most likely marking the front of the shock wave were discovered in its melt products. The experiments clearly showed that np-Fe0 may be formed without participation of a reducing agent, such as implanted hydrogen ions of the solar wind, as well as bypassing the process of iron condensation from shock-generated vapor. The similar np-Fe0 chain structures were detected in the impact glass of the lunar regolith.