The term late veneer refers to the late accretion of asteroidal or cometary material to terrestrial planets. Iron and nickel segregation during core formation leaves the mantle of the planets depleted in siderophile elements, notably platinum-group elements. The modern abundances of these elements in the terrestrial mantle greatly exceed the level expected from such a wholesale removal of metal. It is therefore surmised that 0.5–1.5 % of chondritic or cometary material was brought to the planet by the late veneer after core formation (Dauphas and Marty 2002; Maier et al. 2009). This hypothesis is germane to the issue of water delivery to the Earth.
Ringwood (1966) pointed out that the abundances of siderophile elements such as Ni, Co, Pt, and Os in the upper mantle are remarkably higher than the values indicated by low-pressure partitioning experiments of these elements between metal and silicate phases. Chou (1978) suggested that about one percent of material...
KeywordsSolar System Giant Planet Carbonaceous Chondrite Core Formation Outer Solar System
References and Further Reading
- Dauphas N, Marty B (2002) Inference on the nature and the mass of Earth’s late veneer from noble metals and gases. J Geophys Res-Planets 107:doi:10.1029/2001JE001617Google Scholar
- Ringwood AE (1966) The chemical composition and origin of the earth. In: Hurley PM (ed) Advances in earth sciences. The M.I.T. Press, Cambridge, pp 287–356Google Scholar