A surface related component of iron metal in lunar samples?

Abstract

SOLAR wind elements implanted into lunar soil grains come to rest within a few hundred angstroms, consequently high concentrations should build up in near surface locations. It has become common practice to ‘identify’ surface correlated species by investigating sieved soil fractions; the increased concentrations in fine grain sizes being attributed to the greater surface area. The approach used^1–4, infers a surface location for finely divided iron metal (Fe(0)) and associated hydrolysable carbon (C_hyd) in lunar samples. These studies, together with other evidence⁵, imply solar wind induced reduction processes were involved in producing metal from ferrous iron (Fe(II)) in silicates. The experiments described here performed with a reagent (CuCl₂/2KCl), which should only attack exposed metal, have failed to recognise a genuine exposed surface component. We believe that some effect associated with solar wind sputtering is responsible for iron formation and we must therefore question the validity of the model on which the initial conclusions in favour of surface located metal were based.