First discovery of impact-induced vapor deposition of native copper, FeCo alloy and digenite from Chang'e-5 lunar soil

Meteorite impact and solar wind irradiation are two major processes of space weathering on the Moon, but their effects on lunar soils remain poorly understood. We report the first discovery of native copper and FeCo alloy from a Chang'e-5 lunar basaltic clast. The native copper grains (~0.1–2 μm) coexist unexceptionally with thin Cu-sulfide (digenite) layers (~50–100 nm) that cover troilite, the associated iron whiskers and adjacent pyroxene and ilmenite. The FeCo alloy (~100–200 nm) was associated with the iron metal on troilite. Both Cu and Co are probably exogenous since they are not detected in the troilite. These observations suggest that the digenite layer, native copper and FeCo alloy condensed from an impact-induced vapor with a high Cu/S ratio and Co-bearing composition. Our discoveries shed light on complicated space weathering processes on the Moon.