Zinc,lead, chlorine and FeOOH-bearing assemblages in the Apollo 16 sample 66095: Origin by impact of a comet or a carbonaceous chondrite?

Sample 66095, 89 collected from station 6 from the lunar Highlands in the Descartes Site shows evidence of mild to severe shock. These shock features are accompanied by an unusual enrichment in the volatile elements Cl, Zn and Pb and by the presence of FeOOH.FeOOH occurs in two distinct assemblages: (1) with metallic FeNi, (2) with troilite, sphalerite and two Cl bearing Zn, Fe sulfates. Lead is present exclusively in the second assemblage at the boundaries between troilite and goethite. Lead concentrations up to 0.4% were found. However, the nature of lead-bearing phase is unknown. X-ray fluorescence analyses of a 10 × 6 mm area of the thin section also yielded enhanced chlorine, sulfur and zinc contents.The formation of this unique assemblage and the introduction of the material rich in volatile elements is very probably genetically connected with an impact of a carbonaceous chondrite or a comet. The small range of the reaction between the volatile rich gases and metallic FeNi and troilite indicate a short-live-phenomenon and thus fumarolic activity is a very unlikely process.