Determining the composition of the Earth
Abstract
A long-standing question in the planetary sciences asks what the Earth is made of. For historical reasons, volatile-depleted primitive materials similar to current chondritic meteorites were long considered to provide the `building blocks' of the terrestrial planets. But material from the Earth, Mars, comets and various meteorites have Mg/Si and Al/Si ratios, oxygen-isotope ratios, osmium-isotope ratios and D/H, Ar/H2O and Kr/Xe ratios such that no primitive material similar to the Earth's mantle is currently represented in our meteorite collections. The `building blocks' of the Earth must instead be composed of unsampled `Earth chondrite' or `Earth achondrite'.
- Publication:
-
Nature
- Pub Date:
- March 2002
- DOI:
- 10.1038/416039a
- Bibcode:
- 2002Natur.416...39D