How much oxygen is the earth made of?
1 Answer
Apr 3, 2016
The crust and mantle are made up of silicate rock with varying composition (47% oxygen in the crust and probably a similar amount in the mantle), and beneath that is an iron-nickel core.
Explanation:
See here for more details.
http://www.space.com/17777-what-is-earth-made-of.html
(Note: this is different from the original answer, which describes the Earth's atmosphere rather than the Earth proper.)
